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CYPRESS FLOWS PROJECT
ENVIRONMENTAL FLOW
REGIME AND ANALYSIS
RECOMMENDATION REPORT
AUGUST, 2010
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ENVIRONMENTAL FLOWS REGIME AND ANALYSIS RECOMMENDATION REPORT
TABLE OF CONTENTS 1 Introduction ........................................................................................................................................................... 1
1.1 Cypress Flow Project and SB 3 ..................................................................................................................... 1
1.2 Sound Ecological Environment ..................................................................................................................... 6
1.3 Geographic Scope ........................................................................................................................................ 6
2 Development of Scientifically Based Environmental Flow Regime and Analysis .................................................. 9
2.1 Development of Building Blocks (Environmental Flow Regimes) ................................................................ 9
2.1.1 Literature Review and Summary Report (Reasonably Available Science) ............................................... 9 2.1.2 Flows Workshops and Building Blocks (Preliminary Flow Regime Matrices) ......................................... 27
2.2 Environmental Flow Analysis (Overlays) .................................................................................................... 33
2.2.1 Biology ................................................................................................................................................... 34 2.2.2 Geomorphology ..................................................................................................................................... 49 2.2.3 Water Quality ........................................................................................................................................ 50 2.2.4 Connectivity ........................................................................................................................................... 52
2.3 Environmental Flow Regime Recommendation ......................................................................................... 56
3 Conclusions .......................................................................................................................................................... 59
References ................................................................................................................................................................... 60
List of Available Appendices ........................................................................................................................................ 63
TABLES Table 1 Cypress Basin watershed areas. ....................................................................................................................... 9
Table 2 Geomorphic surfaces in the Big Cypress drainage basin (USACOE, 1994). ..................................................... 16
Table 3 Stream power of a 2‐year recurrence interval flow before and after dam construction. ............................. 18
Table 4 Critical shear stresses required to entrain sediments ranging from medium sand to clay. .......................... 19
Table 5 Average depths required to have sufficient shear stresses to entrain sediments ranging from medium
sand to clay. ........................................................................................................................................................... 20
Table 6 Required discharges to entrain sediments ranging from medium sand to clay. ........................................... 21
Table 7 Impairments in the Cypress Basin. ................................................................................................................. 23
Table 8 Indicator species with flow dependencies. .................................................................................................... 35
Table 9 Habitat guilds for Cypress and Twelve‐mile Creek fishes, based on preferred velocities (horizontal axis
and spawning substrate (vertical axis). Evaluation species are indicated in red bold. (USACE 1994). .................. 36
Table 10 Trends in reproductive guilds in terms of relative abundances. (Pelagophils: Obligate riverine species,
broadcast‐pawn buoyant eggs within current, Lithophils: Includes most Centrarchidae, spawn elliptical egg
envelopes over rock or gravel nests.) .................................................................................................................... 38
Table 11 Segment, reach, and transect‐scale geomorphic and stream habitat measures. ........................................ 41
Table 12 Summary of biotic responses to altered flow regimes in relation to flow‐induced changes in habitat
(principle 1). (Bunn and Arthington 2002). ............................................................................................................ 43
Table 13 Summary of life history responses to altered flow regimes (principle 2). (Bunn and Arthington 2002). .... 43
Table 14 Summary of biotic responses to loss of longitudinal or lateral connectivity (principle 3). (Bunn and
Arthington 2002). ................................................................................................................................................... 44
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Table 15 Summary of biotic responses to altered flow regimes in relation to invasion and success of exotic and
introduced species (principle 4) (Bunn and Arthington 2002). .............................................................................. 44
Table 16 Percent of maximum habitat BG 02 produced by building blocks recommended flow. ............................. 48
FIGURES Figure 1 Sustainable Rivers Project process diagram. .................................................................................................. 2
Figure 2 TCEQ segments in the Cypress Basin in Texas. ............................................................................................... 8
Figure 3 Flow data for USGS gage 07346000 Big Cypress Creek near Jefferson (gage was not active from 1960‐
1979). ..................................................................................................................................................................... 10
Figure 4 Flow data for USGS gage 07346070 Little Cypress Creek near Jefferson. .................................................... 11
Figure 5 Flow data for USGS gage 07346045 Black Cypress Creek at Jefferson. ........................................................ 11
Figure 6 1‐day maximum flows for USGS gage 07346000 Big Cypress Creek near Jefferson. .................................... 12
Figure 7 1‐day maximum flows for USGS gage 07346070 Little Cypress Creek near Jefferson. ................................. 12
Figure 8 1‐day maximum flows for USGS gage 07346045 Black Cypress Creek at Jefferson. .................................... 13
Figure 9 Flow recurrence graph for Big Cypress Creek near Jefferson for pre and post‐dam years. ......................... 13
Figure 10 Flow recurrence for Black Cypress Creek and Little Cypress Creek at Jefferson. ....................................... 14
Figure 11 Date of maximum flow for USGS gage 07346000 Big Cypress Creek near Jefferson. ................................ 14
Figure 12 7‐day minimum flows for USGS gage 07346000 Big Cypress Creek near Jefferson ................................... 15
Figure 13 Date of minimum flow for USGS gage 07346000 Big Cypress Creek near Jefferson. ................................. 15
Figure 14 Generalized block diagram of Big Cypress Drainage Basin showing geomorphic features (USACOE,
1994). ..................................................................................................................................................................... 17
Figure 15 Depth‐discharge relationship at cross‐section downstream of Ferrells Bridge Dam. ................................ 20
Figure 16 Initial building blocks for Big Cypress Creek, May 2005. ............................................................................ 29
Figure 17 Initial building blocks for Caddo Lake, May 2005. ...................................................................................... 31
Figure 18 Initial building blocks for Little Cypress Creek, October 2006. ................................................................... 32
Figure 19 Initial building blocks for Black Cypress Creek, October 2006. ................................................................... 33
Figure 20 Chain pickerel (backwater‐dependent species) life cycle relation to seasonal flow (portrayed relative
to pre‐1957 median flows in Big Cypress Creek) (Winemiller and others 2005). .................................................. 35
Figure 21 Habitat suitability criteria. (USACE 1994). .................................................................................................. 37
Figure 22 Map of USGS study sites. ............................................................................................................................ 40
Figure 23 Map of previous Instream flow study sites. ................................................................................................ 41
Figure 24 Comparison of water surface elevations produced by base dry flows to instream structure (snags) at
BC03. ...................................................................................................................................................................... 45
Figure 25 Comparison of water surface elevations produced by base wet flows to instream structure (Cypress
knees) at BC03. ...................................................................................................................................................... 46
Figure 26 Weighted usable area versus discharge at BG 02. ...................................................................................... 47
Figure 27 Bottomland Hardwood and Cypress forests associated with Cypress Creeks. ........................................... 52
Figure 28 Pressure Transducers installed to measure water surface elevations. ...................................................... 53
Figure 29 Flow rate measured at nearby gage during experimental releases from Lake O' the Pines. ..................... 54
Figure 30 Longitudinal profile of water surface elevation in Big Cypress Creek. ....................................................... 55
Figure 31 Area inundated at 3,000 cfs release. .......................................................................................................... 56
Figure 32 Big Cypress Creek Flow Regime Recommendation. .................................................................................... 57
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1 INTRODUCTION This report is the culmination of an effort begun in 2004 to develop recommendations for environmental flows in
the Cypress River Basin and Caddo Lake based on the best available science.
The Cypress Flows Project (CFP) was originally initiated as part of the Sustainable Rivers Project (SRP) partnership
developed by the Nature Conservancy (TNC) and the U.S. Army Corps of Engineers (USACE). The purpose of this
initiative is to restore and preserve rivers across the country (Richter and others 2006). The CFP was expanded in
the initial CFP orientation meeting in December 2004 to reflect the actions and proposals of the Texas Legislature
to evaluate environmental flow needs in all river basins in Texas. It was further expanded in 2006 with its
integration with a new Watershed Protection Planning process that focused on water quality, aquatic invasive
species and related issues in the Cypress basin. The CFP has benefited from the participation of dozens of
scientists and stakeholders.
With the continued assistance from the USACE, U.S. Geological Survey (USGS), the Northeast Texas Municipal
Water District and many others, the scientists and stakeholders who are participating as the "working group" for
the Project are proceeding with implementation using an adaptive management approach.
The documents prepared for and summarizing the results of the major meetings and other work on this project are
available on the website of the Caddo Lake Institute (www.caddolakeinstitute.us). This report includes a number of
appendices some of which contain information that might be considered beyond the scope of what might normally
be expected as part of the development of a purely science based flow regime as defined by Senate Bill 3 (SB 3).
1.1 CYPRESS FLOW PROJECT AND SB 3
In 2007, the 80th Regular Session of the Texas Legislature passed SB 3, a basin‐by‐basin process to develop
environmental flow recommendations throughout the state. At this time, and even earlier in anticipation of the
passage of SB 3, the CFP began adopting the direction and guidance developed for SB 3 and incorporating the
legislation's central elements. Throughout these various initiatives, the CFP has striven for consistency with SB 3
and respectfully submits this report as the culmination of a voluntary consensus‐building process that satisfies the
SB 3 legislative mandate.
The Texas Legislature enacted SB 3 to create a process for reserving water for environmental flows. The law
provides a state policy for protecting environmental flows, including a process for developing flow
recommendations for each river basin and a framework for final decisions by the Texas Commission on
Environmental Quality (TCEQ) for a set aside of unappropriated water. The CFP began prior to the passage of SB 3,
and therefore, was not executed in exactly the same way as the process was defined in SB 3; however, the CFP is
consistent with the goals and outcomes of SB 3.
While the Cypress basin was not included in the schedule of basins to be addressed by SB 3, the law anticipates
that some basins may develop their own processes. It provides:
“...in a river basin and bay system for which the [state environmental flows] advisory group has not yet established a schedule for the development of environmental flow regime recommendations and the adoption of environmental flow standards, an effort to develop information on environmental flow needs and ways in which those needs can be met by a voluntary consensus‐building process.” [§Sec. 11.02362 (e)]
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Participants in the CFP asked that this type of language be added to SB 3 to open the door for the CFP work to
move forward to obtain a set aside if the CFP process was accepted as the functional equivalent of the SB 3
process. When the language was added, scientists and stakeholders proceeded with the CFP under the
assumption that SB 3 provided for this type of alternative approach and that the CFP is using a process and seeking
results consistent with SB 3.
Representatives from TCEQ, the Texas Water Development Board (TWDB) and Texas Parks and Wildlife (TPWD)
attended all of the flows meetings. Throughout the process, these agencies were consulted and a very
conscientious effort was made to ensure that the work of the CFP would be consistent with expectations of the SB
3 process and goals.
The work of the CFP was also presented to the Texas Environmental Flows Scientific Advisory Committee (SAC) on
October 1, 2008, prior to the last stakeholder‐scientist workshop of December 2008. Some work of the CFP was
also presented to the SAC on March 4, 2009. These presentations were mainly intended to advise SAC members
and others of the work of the CFP, but they were also efforts to seek input from the SAC members and others.
Since then, every effort has been made to provide the type of scientific analysis that the SAC recommended for
other basins.
Thus, the work of the CFP by the stakeholders and scientists of the working group was always focused on the same
basic goals and process as SB 3. The similarities and differences between the two approaches will be discussed
briefly. The SAC has outlined the technical activities to be performed by the Bay Basin Expert Science Teams
(BBESTs) (SAC 2010). These steps are closely mirrored by the process created for the SRP and used to guide the
work of the CFP.
Figure 1 Sustainable Rivers Project process diagram.
The process that was developed for the CFP began before anyone knew what process an environmental flows bill
would provide. There was, for example, no formal process available for appointing stakeholders to the CFP. There
was no process for determining which scientists or stakeholder would participate. Instead, the process was
opened to all who wanted to participate. Recruiting the scientists needed for the work was a three‐step process.
The first step was to identify institutions or individuals with a history of working in the watershed, including those
who have studied the ecology of the system and those who have conducted studies related to proposed water
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development projects. Next, other institutions that were likely to have an interest in this process were identified.
This included local, state and federal agencies, university researchers and private consultants. Finally, the experts
identified were then asked to identify others who might be needed or otherwise should be invited to participate.
The Cypress Basin has attracted scientific studies for many years. Given that Caddo Lake is Texas’ only naturally
formed large lake, there have been strong interests in the Cypress Basin. For example, an expert at the National
Wetland Resource Center in Lafayette, Louisiana had worked on regeneration of cypress trees in the basin for a
number of years. There were also a number of studies associated with the water projects in the basin. These
include studies for existing projects such as Lake O’ the Pines and Bob Sandlin Lake and projects that were not
completed, such as the proposal for a reservoir on Little Cypress Creek and one for a barge canal across Caddo
Lake. A few of these studies included instream flow studies. The studies, and importantly, many of the scientists
who participated in them were available to assist with the Project.
Stakeholders were identified in a similar way. The process began with those known to be interested, and with the
obvious governmental and non‐governmental organizations working in the watershed. That was followed up by
requests that stakeholders help identify other potential stakeholder‐participants. A number of stakeholders not
only played their role of helping set goals for the process to add practical limits to the flow regimes, they also
brought their practical experience and observations to help with the technical evaluations and development of the
flow regimes.
Anyone was allowed to participate in the meetings, as they were open and all materials prepared for or
summarizing the work at the meetings were posted on the website for review and comments. In all,
approximately 200 individuals participated in one way or another. The agencies that participated are listed in
Appendix A.
In Step 1 of the SRP process (Figure 1), experts in riverine, wetland and lake science were invited to participate in a
3‐day orientation meeting to discuss using the SRP process to develop environmental flow recommendations for
the streams in the Cypress Basin and Caddo Lake and associated wetlands. In December 2004, 60‐70 scientists and
stakeholders, including representatives from state and federal agencies, university scientists, regional water
suppliers, conservation groups and local stakeholders, attended the initial orientation meeting for the CFP. While
SRP encourages stakeholder participation and sharing local expertise and concerns throughout the process, it was
repeatedly stressed that the process is firmly rooted in the development of the science to meet technical
challenges of developing building blocks for flows based on ecological needs without consideration of the practical
limitations or other needs for the water. Therefore, while limitations on implementation, such as flooding urban
areas were certainly raised, these were set aside in the process until the science‐based recommendations for
environmental flow regimes were developed. The building blocks were not constrained nor did they consider such
physical or legal limitations or broader goals of stakeholders. Similar to the legislation in SB3, which drew a sharp
distinction between the development of the science to determine the flow needs and a recognition that this be
done "without regard to the need for the water for other uses" and the consideration of "other factors, including
the present and future needs for water for other uses related to water supply planning," participants agreed to
table, for consideration after the development of scientifically determined flow from an ecosystem perspective,
issues related to implementation. The existence of dams creating Caddo Lake and Lake O’ the Pines were taken as
basic limitations, but the limitations on current operations or releases were not. The other goals and limitations
were later added to the discussion for the development of the recommended environmental flow standards after
the science‐based regimes had been developed.
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The preliminary orientation meeting included an overview of the SRP process, including a case study from the
Savannah River (Richter and others, 2006). Using that study as a basic framework, it was emphasized early in the
orientation meeting that the purpose of the process is to develop flow recommendations for maintaining or
restoring the health of the whole river–floodplain–lake system. Specifically, this implied the development of a flow
regime "expressed as a range of magnitudes for each flow component at specific locations, at specific times during
the year, and with a specified frequency of occurrence among years." The objectives to achieve these goals were:
1. To engage interdisciplinary scientists in a collaborative process for developing environmental flow
recommendations.
2. To facilitate interaction among a variety of agencies, academic institutions, and organizations to gain a
shared understanding of the water needs of the basin.
3. To identify critical linkages between various components of the flow regime (low flows, high pulse flows,
and over‐bank flows), lake level fluctuations, and plant and animal species.
4. To develop initial environmental flow recommendations to protect the health of Caddo Lake and its
tributaries
5. To identify research and monitoring activities necessary to fill information gaps and address critical
uncertainties in flow‐ecology relationships.
6. To provide scientifically credible information about environmental flow needs to water managers and
thereby promote the adoption of "ecologically sustainable water management.”
7. To demonstrate a process for developing environmental flow recommendations that can be applied in
other aquatic ecosystems.
Participants worked in breakout groups and discussions focused on ensuring common understanding of the
process that was being proposed, including the level of commitment required to effectively participate, a process
for reaching consensus, and recognition of some of the implementation issues that would need to be addressed
after the preliminary flow recommendations were developed. Participants reached consensus on adopting the SRP
process to develop environmental flows for Caddo Lake and Big Cypress Creek. Action items included identification
of personnel and resources (data and analyses) needed to complete the objectives of the study and identification
of components to be included in the literature review and summary report.
Steps 2 and 3 are analogous to key aspects of the SB 3 process of developing preliminary flow matrices and the
initial application of overlays from the various environmental flow disciplines to produce an environmental flow
analysis and ultimately feed back into a refinement of the preliminary matrices based on reasonably available
science. Steps 4 and 5 are an adaptive management process that is primarily analogous to the workplan and
adaptive management provisions of SB 3. However, because this learning process has already been initiated below
LOP, the CFP has also been able to utilize this process to do further overlay analysis and further refine the flow
matrices. The technical components of these steps are described in detail in the remainder of this report.
It is worth noting and clarifying some differences in the terminology used by the SRP and SB 3 processes. For
example, SB 3 defines “environmental flow regimes” in terms similar to what the SRP refers to as “building blocks."
The terms are not however identical. The scientists working on the CFP developed building blocks as the initial
determination of the numerical flow regimes, but they also recommended narrative conditions to convert some of
the building blocks to the final flow regimes.
For SB 3, SAC guidance has adopted the term "overlay" for the application of expertise and analysis from the
multiple disciplines related to riverine science. SB 3 overlays are most synonymous with the work that goes into
producing the Literature Survey and Summary Report (Step 2) and applying this information in the development of
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preliminary flow matrices. Time and resources have allowed the working group to go beyond what is described as
reasonably available data for SB 3 overlays, to collect data and perform analysis that would not typically be
possible under the time and funding constraints on BBESTs for SB 3. This work (Steps 4 and 5) primarily includes
components of what might be included as elements of a SB 3 work plan but also includes part of the overlay
analysis. This work is therefore summarized in the section of this report that addresses overlay tasks that are
undertaken by the BBEST (Section 2.2). Differences in terminology are unfortunate, in some cases unavoidable.
The working group has moved to adopting the conventions of SB 3 and will use that terminology whenever
possible.
While the SRP and SB 3 processes produce the same outcomes or “functional equivalents" there are several other
differences that are also worth noting. One difference is that the CFP included scientists and stakeholders in
combined meetings, while SB 3 provides for separate meetings. One reason for separating these groups in SB 3
may have been to help protect the integrity of the science. Protecting the ability of the participating scientists to
develop flow regimes based on science is also central to the SRP process. It was strictly adhered to throughout the
development of the environmental flow regime and analysis. It should also be noted that, the CFP did benefit from
the input of many of the stakeholders who brought with them real world experience, observations and information
on conditions and functioning of the rivers, streams and lakes that may not have otherwise been available to the
scientists. The stakeholders also received the benefit of getting a better understanding of the inputs, debates and
results of the science process. This interaction is consistent with the BBEST‐BBASC interactions suggested by the
SAC Lessons Learned document (SAC 2010).
This strong science‐based approach with stakeholder participation was explained by Brian Richter of the TNC when
he led the CFP orientation meeting in 2004. He said, in essence, what he had written the year before:
"Initial estimates of ecosystem flow requirements should be defined without regard to the
perceived feasibility of attaining them through near‐term changes in water management. We
reiterate our assertion that ecological sustainability should be presumed to be attainable over
the long run, until conclusive evidence suggests otherwise. We have been involved in numerous
water management conflicts in which initial perceptions of unfeasibility were overcome through
creativity and deeper analysis, or a change in the socioeconomic or political landscapes that
made possible what had seemed impossible a decade or two earlier.
Inviting water managers and other interested parties to observe the process of defining
ecosystem flow requirements can have important benefits. Water managers can help scientists
understand how to prescribe flow targets in a manner that can be implemented. Water
managers can learn a lot about the possible effects of water management on river ecosystems,
thereby increasing their ecological literacy. Perhaps more important, water managers will gain
insight into the nature of the uncertainties in this knowledge, thereby helping them understand
the need for experiments and flexibility in water management. It is important for water
managers, conservationists, and water users to understand that scientists will not be able to
provide comprehensive and exact estimates of the flows required by particular species, aquatic
and riparian communities, or the whole river ecosystem. Rather, scientists should be able to
provide initial estimates of ecosystem flow requirements that need to be subsequently tested
and refined, as described later." (Richter and other 2003)
When SB 3 was passed and the Cypress Basin was not scheduled, the CFP decided to proceed without revising its
historic process to fit all of the specifics of the SB 3, in large part because the work had provided a solid basis to
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develop the flow regimes and recommendations for standards and strategies called for by SB 3. Both processes
focus on the same goals, i.e., a sound scientific basis for the flow recommendations and consensus on the process.
1.2 SOUND ECOLOGICAL ENVIRONMENT
The SAC defines a sound ecological environment as one that:
Sustains the full complement of native species in perpetuity,
Sustains key habitat features required by these species,
Retains key features of the natural flow regime required by these species to complete their life cycles, and
Sustains key ecosystem processes and services, such as elemental cycling and the productivity of
important plant and animal populations.
Consistent with the above definition is the definition from the Texas Instream Flow Program (TIFP) Technical
Overview document that defines a sound ecological environment as
“A resilient, functioning ecosystem characterized by intact, natural processes, and a balanced,
integrated, and adaptive community of organisms comparable to that of the natural habitat of a
region.”
Instream flow regimes should include flows to provide for instream aquatic habitats, transport of sediments and
maintenance of water quality needed to support diverse plant and wildlife assemblages (SAC 2004). The SAC has
adopted a description of a flow regime that is consistent with the majority of the literature on instream flow
science (NAS 1992; NRC 2005; Locke et al. 2008; Annear et al. 2004; TCEQ, TPWD and TWDB 2008) that includes a
range of flows from subsistence, base, high flow pulse and overbank. These flow components are typically defined
in terms of magnitudes, durations, frequencies and timing. The CFP has adopted a similar set of flows with only
slight modifications. The CFP did not specifically define a subsistence flow because the functions associated with
subsistence flows are captured by what is defined as the dry low flow in the CFP. The CFP also chose to employ the
term "low flow" rather than "base flow." While the ecological function to be maintained by these terms is
identical, the term "base flow" sometimes carries with it a connotation of being groundwater derived whereas the
meaning of "low flow" in the CFP environmental flow analysis is intended to be based solely on the ecological
function expected from these flows and does not connote a source of those flows.
1.3 GEOGRAPHIC SCOPE
SB 3 defines geographic scope based on basin areas and states that flow regimes be developed that "typically
would vary geographically, by specific locations in the watershed." SB 3 does not specify the level of resolution
(number of gages or stream segments) for which flow recommendations must be developed. Clearly, resources
and time prohibit the development of site‐specific recommendations for every river segment.
The entire Cypress basin is within the Austroriparian biotic province and the South Central Plains ecoregion. Most
of the land area within the basin drains primarily from the northwest to the southeast and eventually feeds into
Caddo Lake. It extends upstream from Caddo Lake at the Texas‐Louisiana state border, to the westernmost
extreme of the Cypress Creek Basin, near Winnsboro, Texas. This watershed, which includes several reservoirs, is
formed in the southern part of Hopkins and Franklin and northern part of Wood Counties and flows eastwardly
into Camp, Titus, Morris, Upshur Marion, and Harrison Counties. Black Cypress is to the north of Big Cypress and
begins in Morris County. It flows through Cass and joins Big Cypress in Marion County. Little Cypress is to the south
of Big Cypress and begins in Wood County. It flows through Upshur and Gregg and converges with Big Cypress
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along the Marion and Harrison County boundary. Big Cypress Creek, above Lake O’ the Pines, is intermittent in its
headwaters. It forms the boundary line between Camp and Titus, Camp and Morris, and Morris and Upshur
counties. The stream runs through flat, rolling terrain surfaced by sandy and clay loams that support water‐
tolerant hardwoods, conifers and grasses. Big Cypress Creek flows into Caddo Lake through a jungle‐like
bottomland where cypress trees are common.
The navigable waters of Big Cypress Creek contributed to the rise of the City of Jefferson as a commercial center
prior to the railroads. Between 1842 and 1872, the town was a principal port in Texas, serving as a distribution
point for much of North and East Texas. Once the railroads arrived in the early 1870s, river traffic declined. Since
World War II, Big Cypress Creek has been dammed to form a series of reservoirs including Lake Cypress Springs,
Lake Bob Sandlin, Monticello Reservoir and Lake O' the Pines. Caddo Lake has undergone several very large
changes in the last 200 years. It originally was a natural lake formed by the presence of a tremendous and
apparently ancient logjam. In the 1800s, the original natural dam was removed. This caused the original lake to
shrink with typically very shallow water. This condition persisted for more than 100 years, when, in 1917, the
USACE completed the first dam and spillway to raise the water level. That dam was replaced in 1971 with the
current weir. Outflow cannot be manipulated from the Caddo Lake dam. Water leaves the lake when it overtops
the spillway.
Caddo Lake drains roughly 2,800 square miles, the vast majority of it in Texas. Major tributaries into the Lake are
Big Cypress, Little Cypress and Black Cypress Creeks1 (Figure 2). Together these account for about 70% of the total
drainage area of Caddo Lake. Input from the other 30% of the drainage area is not monitored on a routine basis.
It is up to both the scientists and stakeholders to make some basic decisions on the geographic scope. The
scientists should define a sufficient number of points in keeping with the spirit and intent of the legislation. This is
also an area where stakeholder values play a legitimate and valuable role, as stakeholders may wish to focus on
particular segments or issues. The options for the scope should be sufficient to find an approach that satisfies the
scientific and stakeholders’ needs. Thus, for example, one of the CFP Stakeholders’ initial goals was protection of
Caddo Lake.
CFP defined a geographic scope focused initially on flows into and in Caddo Lake. This focus is partially the result
of the initial impetus of the project, namely the application of the SRP on Big Cypress Creek and Caddo Lake. The
SRP program, as it was developed by the USACE and TNC focuses on changes to reservoir operations to restore
ecosystems that have been impacted by dams. Given the high resource value associated with the lake and
surrounding wetlands, this area was identified as a priority. Caddo has been designated as a Wetland of
International Importance under the 1971 International Ramsar Convention, which has now been ratified by 160
countries including the U.S. Specifics on the designation, its role and impact on the Caddo wetlands can be found
at http://www.caddolakeinstitute.us/ramsar.html. As Texas’ only naturally formed large lake, Caddo Lake also has
important environmental, historic and social values, all of which add to the economic base of the area.
After the orientation meeting in 2004, it became clear that maintaining a healthy ecosystem could not be limited
to a consideration of only Big Cypress Creek, which only represents one third of the watershed for Caddo Lake. (Big
Cypress Creek drains approximately 940 square miles out of the 2,800 total drainage area for Caddo Lake).
1 The terms "Creek" and "Bayou" are used somewhat interchangeably in the Cypress Basin. For ease of writing the term "Creek" will be used in this document although it should be noted that the USGS gage on Black Cypress uses the term "Bayou".
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With gages on Black and Little Cypress Creeks, those streams became obvious systems to include. There was, in
fact, an assumption that the Cypress Basin was small enough and its watershed similar enough that other stream
contributions to Caddo Lake, such as James Bayou, and streams that flow into Louisiana outside the Caddo Lake
Watershed could be evaluated initially based on work done in Big, Little and Black Cypress Creeks. This approach is
necessary because none of these other streams are gaged. By the third flows workshop in December 2008, this
approach led to flow regime recommendations for the ungaged streams in the Cypress Basin. Although the
working group did not make specific recommendations at every gage in the basin (notably at a gage near Pittsburg
on Big Cypress Creek between Lake Bob Sandlin and Lake O' the Pines see Figure 2), they did recommend that the
approach used in the CFP could be used at other locations.
Figure 2 TCEQ segments in the Cypress Basin in Texas.
TCEQ has divided the Cypress Creek Basin into 9 classified segments2. There are currently five active USGS flow
gages in the Cypress Basin and, of these, three are part of the core gage network (Big Cypress Creek near Jefferson,
Black Cypress Creek at Jefferson, and Little Cypress Creek near Jefferson). The three USGS core gages were
selected as primarily sites for the development of instream flow recommendations. The USGS gage at Karnak is a
relatively recent gage with very short period of record. The working group also recommended that flow targets be
2 A TCEQ segment is a section of a river, creek, or stream that has relatively similar chemical, physical, and hydrological characteristics.
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developed for major ungaged tributaries to Caddo Lake (James, Kitchen and Harrison) based on the size of their
drainage areas. In addition, although there was only limited discussion, the group also recognized that the
approach used at the three primary gages could be applied at other segments in the basin, such as Black Bayou.
Table 1 Cypress Basin watershed areas.
2 DEVELOPMENT OF SCIENTIFICALLY BASED ENVIRONMENTAL FLOW REGIME
AND ANALYSIS
2.1 DEVELOPMENT OF BUILDING BLOCKS (ENVIRONMENTAL FLOW REGIMES)
"Environmental flow regime" means a schedule of flow quantities that reflects seasonal and yearly fluctuations
that typically would vary geographically, by specific location in a watershed, and that are shown to be adequate to
support a sound ecological environment and to maintain the productivity, extent, and persistence of key aquatic
habitats in and along the affected water bodies. [§Sec. 11.002 (16)]
What were called Building Blocks at the beginning of the CFP is generally synonymous with what SB 3 refers to as
preliminary flow regime matrices. In the CFP, the Building Blocks were developed after compiling all reasonably
available data (SRP Step 2 ‐ Literature Review and Summary Report) and then assembling scientists with expertise
in hydrology and hydraulics, water quality, fluvial geomorphology and aquatic ecology at a series of flows
workshops (SRP Step 3 ‐ Flow Recommendation Workshops). The scientists analyzed available data and developed
preliminary flow matrices based on an application of expert judgment.
2.1.1 LITERATURE REVIEW AND SUMMARY REPORT (REASONABLY AVAILABLE SCIENCE) A team of scientists from Texas A&M University was contracted to conduct literature review and write a summary
report. (Winemiller and others, 2005) Consistent with state (TIFP 2008) and national (Annear and others 2008)
guidelines, this report included sections on the important river and lake components including Hydrology,
Geomorphology, Water Quality and Macrophytes, Floodplain Vegetation, Aquatic Fauna, Terrestrial and Semi‐
Aquatic Wildlife as well as a summary of Environmental Flow Relationships.
The purpose of the literature report was to synthesize available data and literature associated with Caddo Lake,
Lake O’ the Pines and the streams flowing into Caddo Lake. It was prepared after the orientation meeting in order
to arm initial workshop participants with sufficient information to develop ecologically based flow
Watershed Square Miles Percent TCEQ Segment
Big Cypress 937 32%
above LOP 875 30% 0404
below LOP 63 2% 0402
Little Cypress 719 25% 0409
Black Cypress 399 14% 0402A
James Bayou 322 11% 0407
Kitchen Creek 47 2% 0401B
Harrison Bayou 47 2% 0401A
Caddo (Unspecified) 206 7%
Black Bayou 137 5% 0406
Paw Paw 99 3%
Cypress, Texas 2,911
10
recommendations for the Big Cypress Creek below Lake O’ the Pines Dam and Caddo Lake. Supplements to this
initial report were added as the CFP expanded the geographic scope to include the stream s in the Cypress Basin.
It should be pointed out that hydrologic modifications have not been the only negative impact to this system.
Other perturbations, such as nutrient and contaminant loading, altered sediment transport, logging, drainage and
conversion to agriculture or residential development, have altered the system to varying degrees. However, the
consensus is that some restoration of the timing, magnitude, and duration of flows in Big Cypress Creek together
with the protection of some flows in the other rivers and streams that flow to Caddo are critical to the
sustainability of the lotic, lentic, and floodplain habitats as well as beneficial ecosystem functions.
The following sections were largely extracted from the Literature Survey and Summary Report (Winemiller and
others 2005)
2.1.1.1 HYDROLOGY
With the notable exception of Big Cypress Creek, most of the Cypress Basin is largely unaltered by major instream
impoundments. The major disruption of natural flows into Caddo Lake was caused by the closure of Ferrells Bridge
Dam and creation of Lake O' the Pines on Big Cypress Creek, upstream from Caddo Lake. The Lake O’ the Pines
reservoir was completed in late 1959 and has dramatically altered the flow regime of Big Cypress Creek directly
below Lake O' the Pines. The annual hydrograph for post‐dam conditions is very damped in comparison to pre‐dam
conditions with increased summer low flows, reduced high flow pulses and elimination of larger flood flows (Figure
3).
0
10000
20000
30000
40000
50000
60000
1924 1938 1951 1965 1979 1993 2006
Flow (cfs)
Year
Figure 3 Flow data for USGS gage 07346000 Big Cypress Creek near Jefferson (gage was not active from 1960‐1979).
The natural variability of the flow regime of Little and Black Cypress has been largely unaltered. (Figure 4 and
Figure 5)
11
0
5000
10000
15000
20000
25000
30000
35000
1946 1960 1973 1987 2001
Flow (cfs)
Year
Figure 4 Flow data for USGS gage 07346070 Little Cypress Creek near Jefferson.
0
2000
4000
6000
8000
10000
12000
1968 1974 1979 1985 1990 1996 2001 2007
Flow (cfs)
Year
Figure 5 Flow data for USGS gage 07346045 Black Cypress Creek at Jefferson.
The largest change to flows on Big Cypress has been the change in peak or flood flows as highlighted in Figure 6.
Prior to dam construction, the annual peak flow was as high as 57,000 cfs as occurred in 1945. Following dam
construction peak flows remained around 3,000 cfs with very little variation. The median annual peak flow for Big
Cypress prior to the dam was around 15,000 cfs.
12
Figure 6 1‐day maximum flows for USGS gage 07346000 Big Cypress Creek near Jefferson.
Peak flows at Little Cypress are as high as 30,000 cfs and for Black Cypress are as high as 10,000 cfs.
Figure 7 1‐day maximum flows for USGS gage 07346070 Little Cypress Creek near Jefferson.
13
Figure 8 1‐day maximum flows for USGS gage 07346045 Black Cypress Creek at Jefferson.
Recurrence interval calculations demonstrate the dramatic changes in peak flows that have occurred on Big
Cypress (Figure 9). Prior to dam construction, peak flow of at least 6,000 cfs occurred on an interval of every 2
years. A 20,000 cfs flow occurred on average about every 10 years. The two‐year recurrence interval flows for
Little and Black Cypress are 3,000 and 4,000 cfs respectively.
Figure 9 Flow recurrence graph for Big Cypress Creek near Jefferson for pre and post‐dam years.
14
Figure 10 Flow recurrence for Black Cypress Creek and Little Cypress Creek at Jefferson.
Prior to dam construction at the Lake O' the Pines, most peak flows in Big Cypress were concentrated between
April and May. After the dam construction, the timing of peak flows was shifted more towards the beginning of the
year (Figure 11)
Figure 11 Date of maximum flow for USGS gage 07346000 Big Cypress Creek near Jefferson.
Low flow conditions in Big Cypress Creek have also changed since the Lake O’ the Pines reservoir was constructed.
Figure 12 highlights how the 7‐day low flows have increased in the post‐dam years. The median 7‐day low flow
prior to the dam was around 5 cfs. After the dam, it is around 20 cfs. Of equal if not more importance is that the
timing of low flow conditions has changed dramatically as highlighted in Figure 13. Prior to the dam, low flows
15
were consistently around the first part of September (Julian day 250). Following construction of the dam, the date
of low flow conditions became much more variable.
Figure 12 7‐day minimum flows for USGS gage 07346000 Big Cypress Creek near Jefferson
Figure 13 Date of minimum flow for USGS gage 07346000 Big Cypress Creek near Jefferson.
From an annual average inflow perspective, flow in Big Cypress has been reduced by about 5% following dam
construction, probably because of increases in evaporation from the lake surface. The complete results of the IHA
analysis for Big, Little and Black Cypress are available at caddolakeinstitute.us/flows.html.
16
2.1.1.2 GEOMORPHOLOGY
Changes in Geomorphological Processes
The Cypress drainage basin reflects geomorphological processes active during the past 2 million years. The
geomorphology of Big Cypress Creek (reach between Lake of the Pines and Caddo Lake) was mapped by the U.S.
Army Corps of Engineers, Vicksburg District as part of the Red River Waterway Project (USACOE 1994). Three
geomorphic surfaces were identified according to their physical characteristics, apparent age, and types of
processes active on the surfaces: floodplain, terrace, and valley slopes (Table 2).
Table 2 Geomorphic surfaces in the Big Cypress drainage basin (USACOE, 1994).
Whereas valley slopes are Tertiary in age (65 to 2 million years), the terrace and floodplain were formed primarily
in the Quaternary (2 million years to present) and specifically during the Holocene. Terraces are abandoned
floodplains elevated above the present river’s floodplain; they flood on the order of 100 to 500 years. Floodplains
form by deposition of sediments transported by the stream. In the geomorphic analysis conducted by the U.S.
Army Corps of Engineers (1994), floodplains were defined as the area subject to inundation by a flood with a
recurrence interval of 2 years, following Leopold, Wolman and Miller (1964). The floodplain contains point bars
(which range in thickness from 25 to 30 feet and in texture from sand at the base to finer silts and clays toward the
surface), levees (formed by vertical accretion when the stream floods and deposits suspended sediments along the
banks), and numerous abandoned channels and courses as well as oxbow lakes that form when river channels cut
across their point bars (Figure 14). The Big Cypress is therefore characteristic of a lowland meandering river.
17
Figure 14 Generalized block diagram of Big Cypress Drainage Basin showing geomorphic features (USACOE, 1994).
Channel‐Floodplain De‐coupling
The geomorphological features present on the floodplain are evidence of active river migration and a tight
channel‐floodplain coupling under natural conditions. Before closure of Ferrells Bridge Dam in 1960, the floodplain
upstream of Caddo Lake was inundated every 1‐2 years at a discharge of 6,000 cfs (Figure 9). This flow occupied
the bankfull river channel and is the dominant discharge necessary to form and maintain an equilibrium channel
geometry (Knighton 1998). This is also the discharge needed to sustain floodplain development and riparian
ecosystem.
The immediate result of flow regulation by Ferrells Bridge Dam has been the decoupling of the floodplain from
river channel processes. The closure of Ferrells Bridge Dam has changed frequency‐magnitude relations so that at
present, little variation in flow magnitude exists, and maximum flows do not exceed ~3,000 cfs (Figure 6 and Figure
9). Floodplains are therefore not inundated under the present flow regime. (Quantification of bankfull flow was
identified as a priority research issue early in the CFP. Subsequent field observations indicate that riparian and
flood plain inundation begins at significantly lower flows; between 1,800 and 2,500 cfs in the segment of Big
Cypress Creek above the City of Jefferson. This flow validation work is discussed in detail in Section 2.2.4)
Maximum flows of ~3,000 cfs are also below the dominant discharge necessary to maintain an equilibrium channel
geometry.
18
Sediment Trapping by Lake O’ the Pines Reservoir
Construction of Ferrells Bridge Dam has also affected sediment movement and delivery into Caddo Lake. As
expected, sediment trapping by Lake O’ the Pines Reservoir has reduced sediment input into the downstream
channel reach and ultimately into Caddo Lake. The extent of sediment trapping can be estimated by assessing
changes in storage capacity in the reservoir (Phillips et al. 2004). In 1958, the original conservation reservoir
storage capacity of Lake O’ the Pines Reservoir was 254,900 acre‐feet. By 1998, the reservoir capacity as reported
by the USGS was 238,933 acre‐feet (TWDB 2004). This represents a decrease of 6% in reservoir capacity due to
sedimentation, equaling 492,378 cubic meters of trapped sediments per year behind the reservoir. In some cases,
such as the nearby Trinity River (Phillips et al. 2004) and Sabine Rivers (Phillips 2003), this reduction in sediment
supply downstream of reservoirs is partly offset by increased bank and bed erosion. However, insufficient
information is available for Cypress Creek to determine whether similar erosion processes are producing additional
sediments for delivery into Caddo Lake.
Reduced Transport Capacities
The drastic reduction in flood peaks (Figure 6) is also expected to decrease sediment transport capacities
downstream of Ferrells Bridge Dam. Stream power for a cross‐section represents the total transport capacity of
the river at a given cross‐section and can be calculated for the pre‐dam and post‐dam period. These calculations
were performed for the cross‐section immediately downstream of the dam, where USGS gauging station 07346000
is located.
Stream power is = wQS
where = stream power (N/s)
w = specific weight of water = 9807 kgm‐2s‐2
Q = discharge (m3/s)
S = slope
Using a slope of 2.47 feet/mile or 0.000468 (Slack et al. 2001), the stream power for the pre‐dam bankfull
discharge of 6,000 cfs (that occurred every 2 years, and that inundated the floodplain) is ~779 N/s (Table 3).
Table 3 Stream power of a 2‐year recurrence interval flow before and after dam construction.
Now, under the present flow regime, because the maximum discharge has been reduced to 3,000 cfs (Figure 6),
the maximum transport capacity is ~390 N/s. These results show that sediment transport capacity has been
reduced by 50%. Thus, although increased erosion has been demonstrated to occur below some dams due to
clear‐water or “hungry‐water” effects (Kondolf 1997), these effects tend to be limited to the area immediately
below the dam (Phillips 2003), and the overall effect of reduced flood peaks are decreased transport capacities. A
similar decrease in transport capacities in Yegua Creek downstream of Somerville Dam in south‐central Texas has
resulted in reduced channel capacities over time (Chin and Bowman 2005, Chin et al. 2002).
Time Period Q with 2‐yr R.I. cfs (cms) N/s
Pre‐dam (12924‐1959) 6000 (169.8) 779.33
Post‐dam (1980‐present) 3,000 (84.9) 389.66
19
Sediment Entrainment
To answer the question of whether sediments present in the channel downstream of Lake O’ the Pines are being
transported into Caddo Lake, sediment entrainment calculations were performed. Because quantitative particle
size data are unavailable for Cypress Creek, these calculations were performed for a series of particle sizes ranging
from clay to fine sand, which are known to be typical for this channel reach (Barrett, personal communication).
Two sediment samples collected and analyzed in November 2004 by a student at Texas A&M University were also
in the fine sand range (median sizes of 0.165 mm and 0.097); they corroborate qualitative estimates of particle
size. These samples were collected in the channel close to the banks at locations near Jefferson and at Hwy 43
upstream of Caddo Lake.
Critical shear stresses required to entrain clay, silt, very fine sand, and fine sand were therefore calculated
(diameter equal to 0.0015 mm, 0.02 mm, 0.075 mm, and 0.175 mm, respectively). Two equations were used,
which produced similar results.
Shield’s equation is:
c0.045(s1)gD
where c = critical shear stress (N/m2 or Pa)
D = median diameter of sediments (mm)
s = relative density of sediments to water = 2.65
g = specific weight of water = 9807 kg m‐2 s‐2
Church’s equation is (Church 1978):
c 0.89D
where c = critical shear stress (N/m2 or Pa)
D = median diameter of sediments (mm)
Table 4 shows that, for sediments ranging from medium sand to clay, flows with shear stresses ranging from 0.274
N/m2 to 0.001 N/m2 are required to entrain them.
Table 4 Critical shear stresses required to entrain sediments ranging from medium sand to clay.
To determine flow depths needed to generate the critical shear stresses required to entrain sediments, the
DuBoy’s equation was used:
Class Name Diameter (mm) Shield's c (N/m2) Church's c (N/m
2)
Medium Sand 0.375 0.274 0.334
Fine Sand 0.175 0.128 0.156
Very Fine Sand 0.075 0.055 0.067
Silt 0.02 0.015 0.018
Clay 0.0015 0.001 0.001
20
o = g ds
where o = shear stress (critical shear stress calculated for various sediment sizes using Shield’s and Church’s equations,
Table 4)
g = specific weight of water d = depth (m)
s = slope
Application of the DuBoys equation indicated that, for sediments ranging from medium sand to clay, flow depths
of 60 m to ~0.3 m would have sufficient shear stresses to entrain these sediments (Table 5).
Table 5 Average depths required to have sufficient shear stresses to entrain sediments ranging from medium sand to clay.
The final step to determine whether sediments are capable of being moved under the present flow regime is to
relate the average depths to discharges. Using data available at the channel cross‐section immediately
downstream of Ferrells Bridge dam, where USGS gauging station 07346000 is located, the relationship between
average depth and discharge was established (Figure 15). This relationship enables discharges corresponding to
the calculated critical depths for sediment entrainment (Table 5) to be determined.
Figure 15 Depth‐discharge relationship at cross‐section downstream of Ferrells Bridge Dam.
Combining Table 5 and Figure 15, results indicate that the present flow regime is capable of entraining only silts
and clays. Clays are mobilized at a discharge of ~25 cfs, whereas silts require a discharge of 1,250 cfs to be
entrained (Table 6). Because sands (very fine, fine, and medium) require flow depths corresponding to discharges
that exceed 3000 cfs, which is the maximum flow under the present regulated regime (Figures 2 and 5), they are
not being mobilized by present flows.
Class NameAvg. Depth based on Shield's
m (ft)
Avg. Depth based on Church's
m (ft)
Medium Sand 59.6 (195.7) 72.7 (238.6)
Fine Sand 27.8 (91.3) 33.9 (111.3)
Very Fine Sand 11.9 (39.1) 14.5 (47.7)
Silt 3.2 (10.4) 3.9 (12.7)
Clay 0.24 (0.78) 0.29 (0.95)
21
Table 6 Required discharges to entrain sediments ranging from medium sand to clay.
Sediment Delivery into Caddo Lake
The last piece of available data to give insight to the issue of sediment delivery into Caddo Lake is analysis of
sedimentation rates within Caddo Lake (Barrett 1995, Lisanti 2001). Modern sedimentation rates (1963 to present)
were measured using gamma ray spectroscopy at seven sites within Caddo Lake (Lisanti 2001), yielding
sedimentation rates ranging from 0.22 cm/year to 0.56 cm/year, with two sites not measurable. Although Caddo
Lake receives sediment input from sources other than Cypress Creek, and thus sedimentation rates within the lake
are not perfect analogs for sediment delivery through Cypress Creek, variations in sedimentation rates
nevertheless give additional information to corroborate previous analyses. It is worthy to note that the two sites
located immediately at the outlet of Cypress Creek (Cypress Bayou delta) have the lowest sedimentation rates
(both 0.22 cm/year). These sedimentation rates are only half of the rate of 0.56 cm/year at the outlet from James
Bayou. Low sedimentation rates at the Cypress Creek outlet support previous conclusions that 1) sediment
supplies are reduced downstream of Lake O’ the Pines; 2) sediment transport capacities are reduced due to a
drastic reduction in flood peaks; 3) only the finest sediments (clays and silts) are being mobilized under the current
flow regime.
In summary, both flow regime and sediment regime have been altered by flow regulation at Ferrells Bridge Dam
since 1960. The overall result is a river floodplain disconnected from the river channel at present.
The high flow regime does not appear to have changed in Black and Little Cypress Creeks and therefore it is
expected that natural sediment transport characteristics remain largely unchanged in these drainages. The caveat
to this is that the sediment load characteristics may have changed because of timber and agricultural activities;
however, these land use alterations have not been investigated as part of this study.
2.1.1.3 WATER QUALITY AND MACROPHYTES
The analysis of the relationship of flows and water quality relied upon several documents and the work of the
Watershed Protection Planning Process. The basic documents included:
Texas A&M Summary Report Supporting the Development of Flow Recommendations, 2005
(http://www.caddolakeinstitute.us/Docs/TAMU_SummaryReport_April2005.pdf)
Cypress Creek Basin Summary and Highlights Reports (http://www.netmwd.com)
Analyses prepared for the Caddo Lake Watershed Protection Plan (http://www.netmwd.com)
Draft Discussion Paper on Flows and Water Quality by Tim Osting, Espey Consultants, Inc. 2008.
(http://www.caddolakeinstitute.us/docs/flows/dec08meeting/draft_discussion_paper_on_flows_and_wa
ter_quality.pdf)
The Cypress Creek Basin appears to be at the transition zone between a mesotrophic and eutrophic system. The
process of eutrophication seems to be accelerated in some of the subbasins due to anthropogenic activities within
Class NameAvg. Depth based on Shield's
m (ft)
USGS x‐sctn
cfs
Medium Sand 59.6 (195.7) >3000
Fine Sand 27.8 (91.3) >3000
Very Fine Sand 11.9 (39.1) >3000
Silt 3.2 (10.4) 1250
Clay 0.24 (0.78) 25
22
the watershed, including nutrient loadings. (NETMWD 2010) Many other water quality parameters, such as
dissolved oxygen, bacteria, mercury and pH have become problematic. According to the state’s 303(d) listings, the
number of impairments in the Cypress Creek Basin continues to increase.
The latest Basin Summary Report for the Cypress Creek watershed, by Water Monitoring Solutions, Inc., in 2009
provides a review of the historical water quality data and trends based on the TCEQ Surface Water Monitoring
Information System database. The Basin Summary states that water quality over the period of record has
remained relatively stable in the Little Cypress Creek and Black Cypress Creek watersheds. However, significant
trends were found in Big Cypress Creek beginning in Lake Cypress Springs and Lake Bob Sandlin and ending in the
upper end of Caddo Lake. The report identifies five statistical trends:
Increasing trends for specific conductance/TDS throughout the Big Cypress Creek watershed,
Increasing trends for pH in Big Cypress Creek and James Bayou,
Increasing trends for phosphorus in Big Cypress Creek below Lake Bob Sandlin and corresponding
increasing chlorophyll a trends in Lake O’ the Pines,
Decreasing DO in the upper portion of Caddo Lake, and
Decreasing DO and pH along with increasing chlorophyll a in Black Bayou.
Fourteen stream segments in the Cypress Creek watershed have been listed as impaired or not supportive of water
quality criteria for one or more parameters. The number of impairments generally continues to increase with
several added by TCEQ in 2010. The most common parameters listed were dissolved oxygen, pH, E. coli, bacteria
and mercury in fish tissue. Nutrients and chlorophyll a were also identified in the 2008 Texas Water Quality
Inventory as water quality concerns in the watershed.
23
Table 7 Impairments in the Cypress Basin.
Located at the bottom of much of the Cypress watershed, Caddo Lake receives contaminants from a wide variety
of activities. In addition to the trends toward eutrophication, a major concern has been the rampant growth of
macrophytes, especially in the upper reaches of Caddo Lake. These have created significant problems for use of
the Lake and, with decay, they increase the accumulated biomass, which adds to the conditions of low dissolved
oxygen and may fuel summer phytoplankton blooms and fish kills. Levels of mercury in bass and some other large
fish has lead to fish consumption advisories, warning of the risks of eating too much of these fish.
High inflows during the summer months when temperatures are highest and dissolved oxygen and pH are lowest
appear to be the most beneficial to water quality problems, including nutrients, in the Lake. It is unclear from
available data whether high flushing during winter and spring months will have a strong impact on summer
months.
High inflow and lake‐level lowering are possible strategies that should be examined to address water quality and
macrophytes. There are not likely to alleviate the problems entirely. Control options involving mechanical removal
and the application of chemicals and biological controls are also likely to be needed.
Lower inflows will not flush nutrients from Caddo Lake as quickly as higher inflows. For the same reasons
mentioned above, intermediate and low flows will be more effective at flushing nutrients from the system during
the summer months. Low inflows would likely have very little impact on alleviating potential problems associated
with low dissolved oxygen and pH. In other words, during conditions of low inflow Caddo Lake will likely continue
Segment Description Parameter
401 Caddo Lake Low DO, Low pH, High Mercury in Tissue
0401A Harrison Bayou Low DO
402 Big Cypress Bayou below Lake O’ the Pines Low pH, High Mercury in Tissue
0402A Black Cypress Bayou Low DO, High Bacteria, High Mercury in Tissue,
High Copper*
404 Big Cypress Creek below Lake Bob Sandlin High Bacteria, Low DO*
High PCBs in Tissue, High Sediment Toxicity
High Copper*
0404B Tankersley Creek High Bacteria
0404C Hart Creek High Bacteria
0404N Lake Daingerfield High Mercury in Tissue
0404O Dragoo Creek High Bacteria*
0404P Unnamed tributary to Tankersley Creek High Bacteria*
0404Q Unnamed tributary to Tankersley Creek High Bacteria*
0404R Unnamed tributary to Dragoo Creek High Bacteria*
405 Lake Cypress Springs Low DO (has been removed)
406 Black Bayou Low DO, Low pH, High Bacteria
407 James’ Bayou Low DO, Low pH, High Bacteria
409 Little Cypress Bayou (Creek) Low DO, High Bacteria, High Copper*
0409B South Lil ly Creek High Bacteria
*Added in 2010.
0404A Ellison Creek Reservoir
24
to be plagued by periodic conditions of poor water quality. It is not clear, however, whether these were
characteristic traits of the system which occurred during historical (i.e. pre‐Lake O’ the Pines Dam) low flow
periods.
Lake drawdown has been an effective tool to help control growth of submerged and floating macrophytes in some
lakes. For Caddo Lake this might not be a viable option in the future, but releases from the current dam only occur
as water flows over the spill way.
2.1.1.4 FLOODPLAIN VEGETATION
In the Cypress Creek Basin and around the greater Caddo Lake area, bottomland hardwood and bald cypress
forests occupy areas of the floodplain ranging from low areas that are permanently inundated to higher areas that
are infrequently inundated, yet may still have saturated soils. It is widely accepted that the structure and function
of these alluvial river swamps is tightly coupled with hydrologic energy. In fact, hydrologic variability may be the
single most important factor affecting the local distribution of bottomland tree species within their natural ranges.
In alluvial settings such as the Big Cypress Creek floodplain, these forested wetlands receive periodic disturbances
in the form of a flood pulse that is important in delivering nutrients and altering soil physico‐chemical properties to
the point that upland species are excluded. The high flows typical of these events are also important in scouring
and dispersing many of the seeds produced in alluvial river swamps.
The key to the establishment and long‐term maintenance of these wetland forests is through seedling recruitment.
Without periodic, successful recruitment of new seedlings, these systems may become more even‐aged and more
susceptible to human perturbations. For most of the species found in these forests, seeds are released in late
summer/early fall—usually between September and October. For the Caddo Lake region, this period historically
was the dry season and corresponded with low flows in the Big Cypress Creek basin. Rapid growth—from seed
germination–seedling stage—up to the next flood pulse (usually in late winter/early spring) is needed for the
successful establishment of a new cohort of saplings in the forest. These hydrologic conditions prevailed up to the
installation of the dam for Lake O’ the Pines in the 1950s. In fact, it has been suggested that seedling recruitment
has been depressed in some areas of the Big Cypress and Caddo Lake region because of these hydrologic
alterations. Still other past impacts such as logging and drainage and fill of adjacent floodplain area and nutrient
enrichment need to be considered in addition to biotic processes such as herbivory and exotic species invasion.
Recommendations are for high flows to occur during the historic early spring flood pulse period. These high flows
will scour and distribute seeds to a large area of the floodplain and should start to decline into late spring,
bottoming out in early summer. Low flows in Big Cypress Creek during the historical dry summer will then be
needed to allow for the establishment (i.e. germination) of seeds and growth to a level at which many will be able
to survive the following year’s spring high water period. Periodic draw down in Caddo Lake will also likely be
important in recruiting a new generation of bald cypress to this perennially lentic environment.
2.1.1.5 AQUATIC FAUNA
Fishes obviously depend on in‐stream flows to provide aquatic habitats in which to live, but there are many other
direct and indirect effects of water availability, flow characteristics, and water quality on fish behavior and ecology.
In lowland floodplain rivers, such as the major tributaries that deliver water to Caddo Lake, the annual hydrological
regime greatly influences the quantity, quality, and connectivity of aquatic habitats that are required by the
various fish species during each stage of their life cycles. The fish fauna of the Cypress Basin can be divided into
four groups: 1) fishes directly dependent on flowing channel habitats, 2) fishes directly dependent on non‐flowing
backwater habitats, 3) fishes not directly dependent on flowing or backwater habitats but which may use either to
varying degrees, and 4) migratory fish.
25
Rather than develop an exhaustive assessment of each fish species, we have developed a list of “indicator” species
under each category that may be useful in establishing targets for restoration. Some of these species are
threatened, in a few instances are now locally extinct, as a result of hydrologic modifications and perhaps other
impacts.
The paddlefish (Polyodon spathula) has been greatly reduced in abundance and distribution throughout its range
due to pollution and especially construction of dams that block migration routes, regulate flow, and alter channel
geomorphology and substrate composition. Paddlefish spawn in the spring when water levels rise rapidly. After
the larvae develop within deep pools of the main channel, the juveniles move into backwater (lentic) habitats.
Spring floods have been greatly curtailed in Big Cypress Creek, and this may have eliminated cues and conditions
needed for spawning. In addition, the lack of floods has likely resulted in the degradation of shoal habitats that are
critical spawning habitat for this species.
The chain pickerel (Esox niger) spawns during late February and early March and requires lentic habitats for all
stages of its life cycle, even during the egg‐laying stage when eggs are typically scattered in littoral vegetation. In
terms of its in‐stream flow requirements, the chain pickerel would benefit from flow regimes that maintain
permanent aquatic habitat in the floodplain. Periodic pulsed flows would be important for dispersal of juvenile and
adult pickerels among lentic (backwater) habitats along the margins of the main channel as well as within the
floodplain.
The largemouth bass (Micropterus salmoides) nests in backwater areas lacking current, either along river or stream
margins or in floodplain habitats such as oxbow lakes. It spawns from April until June, with spawning initiated
when the water temperature rises above 65°F. Caddo Lake provides an outstanding habitat for this species, which
would only be enhanced by maintenance of a flow regime on Big Cypress Creek that maintains oxbows and other
permanent lentic habitats in the floodplains and facilitates dispersal.
The freshwater drum, or gaspergou, (Aplodinotus grunniens) occurs in pools where it feeds on benthic
invertebrates. The drum spawns during April or May near the surface of the water column and buoyant eggs float
with the current before hatching into larvae, that also float. At the post‐larval stage, they move to the bottom
where they begin feeding as juveniles. The freshwater drum has flow requirements for spawning and dispersal of
early life stages that are very similar to those described for paddlefish. It might also benefit from extended periods
of low flow during summer, as this should enhance benthic foraging opportunities.
The bluehead shiner (Pteronotropis hubbsi) is a threatened species that schools in backwaters and marginal areas
away from significant current and seems to spawn from early May to July. It appears that late spring and early
summer low flow conditions may be most conducive to successful spawning and recruitment by this rare species,
but its presence in oxbow lakes reveals a necessity for periodic overbank flows allowing dispersal between channel
and oxbow habitats.
The Bigmouth buffalo (Ictiobus cyprinellus) and smallmouth buffalo (Ictiobus bubalus) do not seem to be strictly
dependent on flow regime, but may show enhanced recruitment under appropriate flow regimes. Both species
initiate spawning around April in shallow, lentic backwaters after spring floods raise water levels. Therefore, pulsed
flows during spring or other periods of the year would allow dispersal of immatures and adults between channel
and floodplain habitats.
The ironcolor shiner (Notropis chalybaeus) spawns from mid April until late September, and eggs are scattered in
stream pools over sand substrate. It seems unlikely that reproduction and recruitment by this small stream‐
26
dwelling minnow are highly dependent on pulse flows during spring. One could even hypothesize that extended
periods of low flow over the summer could enhance recruitment in this spring‐summer spawning species.
Big Cypress Bayou and other associated drainages are home to a very diverse freshwater mussel assemblage with a
least 26 species identified since 1913 (Howells 1996). One species, the Louisiana pigtoe (Pleurobema riddellii),
documented by Mather and Bergmann (1994) is one of the rarest Texas unionids and has a state ranking of S1
(critically imperiled). Another S1 ranked unionid, the sandbank pocketbook (Lampsilis satura), is thought to inhabit
the Cypress Bayou system (Marsha Mays, personal communication), but has never been documented. Howells
(1996) suggested that, while the Cypress Bayou systems still support relatively abundant unionid populations,
habitat alteration and degradation have reduced populations from historic levels. In addition, he states that many
species tolerant of soft bottom habitats and eutrophication were represented by multiyear classes indicating
successful reproduction. In contrast, heavily shelled species were represented by older adults only and no signs
were found of recent reproductive success in these species. Because many mussel species require a host fish for
their parasitic glochidial stage of development, and rely on flow for dispersal of offspring and settlement of
juveniles, environmental flows that favor fishes will also favor mussels.
2.1.1.6 TERRESTRIAL AND SEMI‐AQUATIC WILDLIFE
The streams, wetlands, open water bodies, and bottomland forests of the Cypress Basin support a rich and
abundant herpetofauna, with 45 species documented by a study that surveyed a relatively small area. Many,
perhaps most species, would respond to restoration of aquatic floodplain habitats with enhanced populations. In
some cases, this population enhancement would result from creation of additional breeding and rearing habitats,
and in other cases, it would be a response to additional food availability and foraging opportunities. In addition,
pulse flows provide connectivity of aquatic habitats that permit dispersal by semi‐aquatic species.
Two of the state’s “threatened” reptiles occur within the basin—alligator snapping turtle (Macrochelys timminckii)
and the timber rattlesnake (Crotalus horridus). The bird assemblage of the basin is estimated to contain 313
species. Two of the state’s threatened bird species are likely to use habitats present in the basin—whitefaced ibis
(Plegadis chihi) and woodstork (Mycteria americana). The region is an important migratory corridor for many
species, with several lakes in the basin used by wintering waterfowl for foraging and resting. Degradation and
losses of wetland habitat are considered the major threats to waterfowl. Although many waterfowl now obtain
significant food resources from flooded agricultural fields, forested wetlands are required to meet the full
biological requirements of most species. Little research has been conducted on mammals of the Caddo Lake
region. Historically, the red wolf (Canis rufus) and Louisiana black bear (Ursus americanus luteolus) would have
inhabited the region. A two‐year survey of the Longhorn Army Ammunition Plant recorded 10 species, with
taxonomic diversity greatest in the pure pine areas, and abundance greatest in the mixed pine‐hardwood. Semi‐
aquatic mammals in the basin include the beaver (Castor candadensis) and river otter (Lutra canadensis).
2.1.1.7 SUMMARY OF ENVIRONMENTAL FLOW RELATIONSHIPS
A major alteration of the natural flow regime in the basin occurred when Ferrells Bridge Dam was constructed on
the main stem of the upper Big Cypress Creek in the late 1950s. Flow regulation results in elimination of flood
flows during late winter‐early spring and greatly reduced pulse flows year‐round and increased summer low‐flows.
This in turn results in reduced bed scouring (yielding loss of structural habitat diversity within the channel and
creation of backwater habitats), sediment delivery, sediment deposition on floodplains, and over‐bank flooding. All
of these changes have detrimental effects on aquatic and riparian population dynamics, which ultimately results in
reduced species diversity and smaller populations of species of plants, and animals that depend on the natural
flow regime for creation of essential habitat for foraging and reproduction, maintenance of ecosystem
27
productivity, and/or dispersal. For example, the paddlefish (breeding population was extirpated in the early 1960s)
required flood flows to maintain shoals and to provide cues for spawning. This species also required periodic pulse
flows to allow movement between channel and backwater habitats used by juveniles and adults for foraging.
Similarly, the major bottomland hardwood tree species required high flows for seed dispersal and to limit
encroachment of upland tree species into floodplains. Flow regulation also results in higher daily flow fluctuations
and higher late spring and early summer flows, which result in lower water temperatures. These changes impact
benthic ecosystem productivity in the channel, foraging opportunities for benthivorous organisms, fish growth
rates, and spawning by aquatic species that depend on stable, low flows during summer. These impacts result in
degraded fisheries, decline of sensitive and rare species, alteration of aquatic and riparian communities and
ecosystems. Although it provides about a third of the total inflow to Caddo Lake, flow regulation in Big Cypress
Creek probably has major effects on the lake ecosystem. Sufficiently high inflows would influence nutrient
concentrations and phytoplankton dynamics. During periods of low flow, internal nutrient dynamics (involving
sediments, bacteria, water column, macrophytes and algae) would be prevalent. Prolonged periods of low‐flow,
uninterrupted by pulse flows, during late summer result in acute aquatic hypoxia in the shallow (deltaic) upper
segment of the Lake.
2.1.2 FLOWS WORKSHOPS AND BUILDING BLOCKS (PRELIMINARY FLOW REGIME MATRICES) Flow regime matrices were developed and revised at three multi‐day flow workshops and at numerous subgroup
meetings, which occurred between the full workshops.
First Workshop ‐ May 2005
At the first workshop, three days in early May 2005, the initial work was the development of a first cut at building
blocks for Big Cypress Creek downstream of Lake O’ the Pines and for Caddo Lake. The goal was to develop
proposals that could be tested with releases from Lake O’ the Pines, while the CFP gathered additional
information, including information on whether building blocks for other rivers and streams could be based on the
approach taken with Big Cypress Creek. The building blocks were intended to enhance the ecological structure and
function of Big Cypress Creek, its floodplain, and Caddo Lake, with the ultimate goal of providing benefits to local
flora, fauna, and stakeholders in the region. Document reports on the historical flow conditions (i.e., pre‐dam) in
Big Cypress Creek and their role in shaping the lotic, lentic, and floodplain ecosystems of this region.
Over eighty scientists, water managers, and local community members participated in the first workshop. After
reviewing the data and analysis included in the literature survey and summary report, including presentations on
each of the major disciplines, participants worked together in breakout groups to qualitatively define necessary
dimensions of the flow component patterns including magnitudes frequencies, durations and timing for a full
range of hydrologic conditions and inter and intra‐annual variation. The workgroup also identified knowledge gaps
and prioritized research tasks that would be necessary to validate or, if necessary, refine these preliminary
recommendations.
Second Workshop ‐ October 2006
The second multi‐day workshop was held in October 2006, and the work focused on developing building blocks for
Little and Black Cypress Creeks, after considering possible changes to the building blocks for Big Cypress and Caddo
Lake. Because of drought conditions, the CFP had not had the opportunity to test assumptions and the building
blocks with releases from Lake O’ the Pines. The needed rains came in January 2007. Thus, the building blocks
developed in the May 2005 workshop were not changed.
28
To prepare for the work on Little and Black Cypress Creeks, a supplement to the literature survey was completed,
including IHA and recurrence interval flow statistics for these streams. There was first a discussion of whether the
building blocks for Black and Little Cypress could be developed by using the approach used for the building blocks
for Big Cypress Creek. The consensus was that this approach was appropriate.
Third Workshop ‐ December 2008
A third flows workshop was held in December 2008 at which time the results of targeted research facilitated an
environmental flow regime analyses (application of overlays) leading to several refinements of the preliminary
flow regime matrices. The working group also decided to make a significant adjustment to the form of the flow
recommendations on the unregulated sites on Little and Black Cypress by adopting a narrative approach for Black
Cypress and hybrid (part Building Block, part narrative) approach for Little Cypress. This decision was motivated by
the recognition that the wetlands associated with Caddo Lake have very high resource value and the concern
expressed at the second workshop that the limited high flow events defined by the building blocks might not be
satisfactory to maintain the ecological health of these streams that currently experience largely unaltered flow
regimes. At this third flows workshop, the working group also made recommendations to develop flow regimes at
ungaged sites based on drainage area adjustment. Having reached consensus on the science‐based environmental
flow regime recommendations; the CFP began the process of developing flow standards and strategies. The
results of this process will be presented in a subsequent report.
2.1.2.1 BIG CYPRESS CREEK
The initial building blocks for Big Cypress Creek, developed in May 2005, are presented in Figure 16. (The revised
final flow recommendations are in Figure 32) The flows portrayed in this figure include magnitudes, duration and
seasonal timing as well as a prediction of the ecological outcome that would be expected if the flow condition
were attained.
29
Figure 16 Initial building blocks for Big Cypress Creek, May 2005.
The low‐flow targets are based upon a variety of ecological objectives. The fish habitat objectives are based upon
on overlay of fish habitat simulation modeling performed by the USFWS and USACE (Cloud, 1984, USACE 1994).
Other targets were based upon the fish habitat modeling results as well as a review of the pre‐dam low‐flow
conditions for each month, as derived from the “Indicators of Hydrologic Alteration” (IHA) software. For instance,
the 25th percentiles of the pre‐dam flows were largely used as a basis for the July‐September flows in dry years,
medians were used for setting the October‐February average flows, and the 75th percentiles were used as a
reference in setting wet year flows.
The high‐pulse flows in December‐June were based upon pre‐dam flow records, ecological information provided in
the Summary Report, and professional judgment. Based on analysis of pre‐dam flow data, historical durations and
frequencies of these high flow events were somewhat larger than what is recommended by this matrix, however
biologists participating in these discussions felt that fish and other mobile aquatic and amphibious organisms
would be able to move into or out of secondary channels and oxbow lakes fairly quickly (e.g., during a single day)
during these high‐flow pulses. The duration of these events was set at 2‐3 days to allow for some ramping time on
the rising and falling limbs of these high‐flow pulses. Fluvial geomorphologists similarly felt that necessary
sediment transport could also occur during these short pulses. After some discussion about the fact that the
median duration of high‐flow pulses was 11 days during the pre‐dam period, workshop participants agreed that
the high‐flow pulse duration deserved close attention during the implementation and adaptive management phase
30
of the project. Similarly, because high‐flow pulses occurred with a median frequency of seven times per year in the
pre‐dam period, the number of pulses to be targeted should be closely examined.
The 6,000 cfs target for channel maintenance is based upon the assumption that the pre‐dam 2‐year flood
magnitude approximates the bankfull discharge level. It is well established in the geomorphic literature that the
bankfull discharge is the level at which the majority of sediment transport occurs, and is therefore a primary
determinant of channel geometry (i.e., width and depth of the river channel). An accurate determination of the
bankfull discharge level has been identified as a top‐priority research need (Appendix B). Based upon this research,
the flow magnitude and necessary recurrence interval for this building block was later refined.
Somewhat less frequently (i.e., at 3‐5 year intervals), a flow of 6,000‐10,000 cfs would be needed to provide
additional ecological benefits including riparian seed dispersal, maintenance of aquatic habitats in the floodplain,
and maintenance of riparian vegetation diversity. Even less frequently (10 year intervals), a flood of 20,000 cfs
would be needed to drive channel migration across the floodplain, which is an important mechanism for creating
or maintaining habitat for both aquatic and terrestrial organisms.
2.1.2.2 CADDO LAKE
Caddo Lake received special attention because of its location at the bottom of the Cypress Basin. It also has been
designated as a “Wetland of International Importance” under the Ramsar Convention, now signed by 160 nations.
(see caddolakeinstitute.us/ramsar.html)
One outcome of the first workshop was an initial finding that management of flows in Big Cypress Creek may not
need to be adjusted to benefit Caddo Lake. This was based largely upon the fact that Big Cypress contributes
about one‐third of the total inflow to Caddo Lake. The other two‐thirds entering Caddo Lake comes from other
tributaries that are currently largely unaffected by dams or diversions. These relatively natural inflows from other
tributaries result in a considerable rise in lake levels during floods and can provide flows to Caddo sufficient to
inundate most of the wetlands around the lake.
The dam for Caddo Lake, which is a weir, is fixed with the lowest spillway at an elevation of 168.5 NGVD. Under
present conditions, the lake level will drop below that elevation during low flows, but these reduced levels of the
lake do not often exceed 2 feet.
The workshop participants recommended an evaluation of the option of installing an outlet that would allow
lowering lake levels for a number of purposes, including nutrient management, cypress regeneration, and invasive
species control. (In 2010, the U.S. Army Corps of Engineers announced a plan to begin a study that would include
the feasibility of replacing the weir with a dam that includes an outlet for lowering lake levels.)
The consensus was also that nutrient levels in Caddo Lake are contributing to the undesirable abundance of
aquatic plants, phytoplankton blooms and conditions of low dissolved oxygen. The participants concluded that
lake flushing could more efficiently be accomplished by drawing down the lake and that any such nutrient removal
effort should be carried out adaptively, using monitoring to inform decisions about the necessary design and
duration of the Project.
Another potential benefit of lake lowering could be bald cypress regeneration in areas that presently do not dry
sufficiently to allow seed germination and seedling recruitment. Such a drawdown might need to occur in at least
two consecutive growing seasons for this goal, and, thus, could have significant impacts on use of the lake and the
local economy.
31
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Lake Level Building BlocksCaddo Lake
Low Lake Levels
Normal Lake
Levels
High Lake
Levels
Key
Dry Year
Avg Year
Wet Year
Lake refillingfollowing nutirent and sediment
flushing(requires approx. 15 days?)
Inhibition of upland tree species from encroaching into lake
fringe areas (occurs naturally; requires xx days of
Inundation every xx years)
Lake level lowering fornutrient and sediment flushing
(once every year for up to 10 years)
Lake level lowering forcypress regeneration
(once every 10-20 years, for twoconsecutive growing seasons
Figure 17 Initial building blocks for Caddo Lake, May 2005.
2.1.2.3 LITTLE CYPRESS AND BLACK CYPRESS CREEKS
The second Flows workshop expanded the geographic scope of the CFP to include the other major gaged
tributaries to Caddo Lake. There was a consensus that the building blocks for Black and Little Cypress could be
developed by using the approach used for the building blocks for Big Cypress Creek. The original summary report
included data from the entire basin and was again used to inform workshop participants’ decisions. A
supplemental report was prepared to include a hydrological analysis of the historical data from these tributary
gages using the IHA software. Breakout groups were again relied upon to facilitate discussions.
One breakout group proposed that Black Cypress Creek be designated an “untouchable” stream, essentially setting
a narrative flow regime on top of the building blocks that would assure adequate pulse and flood flows for the
Creek and to help protect Caddo Lake. The group felt that Black Cypress Creek should remain in the as pristine a
state as possible to serve as: (1) a source of unregulated flows to Caddo Lake; (2) a reference state for other
creeks; and (3) a refuge for biota. (In 2010, The North East Texas Regional Water Planning Group recommended
that Black Cypress Creek also be designated an Ecologically Unique Stream Segment.)
This breakout group also proposed that historically large flood events should still occur on Little Cypress, to
maintain the wetlands associated with Caddo Lake, however there was also a consensus that this segment may not
require the same level of protection was recommended for Black Cypress.
There was consensus on the use of the IHA‐EFC 25th, 50th and 75th monthly low flow percentile values as
reasonable starting values for the base flows. There was some discussion of augmenting the IHA‐derived monthly
percentiles with values developed in the Physical HABitat SIMulation (PHABSIM) study conducted by the USFWS
(USFWS 84) and it was suggested that the same could be done for Little Cypress. The recommended flow from
PHABSIM for Black Cypress in September was 75 cfs while the monthly median flow was 3 cfs and for Little Cypress
32
the PHABSIM recommended September flow was 75 cfs while the median was 11 cfs. Stipulating an August and
September low flow of 75 (seven to twenty times greater than the median flow) would change the creeks from
ones that frequently had intermittent flow during the dry season to ones that had consistent elevated base flows.
Therefore, the flows recommended by that study were not adopted in the Building Blocks.
It was recognized that very low flows, specifically the 25th percentile flows for August‐October, might result in a
series of disconnected pools. In order to maintain the connectivity between pools, it was proposed that the
absolute minimum flows for Little and Black Cypress should not be less than 5 and 4 cfs, respectively.
While there was a consensus to follow the Big Cypress approach for the high‐flow pulse target at the 2‐year flood,
there was again considerable discussion about what this flow represents, e.g. whether it reflected the bankfull
flow or the effective discharge. Based on the USGS’s preliminary analysis on Big Cypress, it was felt that the 2‐year
flood may overestimate the physical bankfull flow. Therefore the lower bound on the 95th percentile confidence
interval of the 1.5‐year flood, which in Big Cypress was close to the bankfull observed by the USGS, was selected as
a lower range and an upper range, to ensure that the water will get up steep banks in some areas.
There was also consensus to develop building blocks for large floods in a manner similar to the approach used for
as the building block for Big Cypress. For Big Cypress, a building block for a large flood stipulated that a flood of
20,000 cfs (approximately 10‐year recurrence interval) should occur once every ten years on average. Thus, for
Little and Black Cypress, floods of approximately 13,000 and 8,000 cfs for 2‐3 days every ten years were proposed
for late winter or spring.
Figure 18 Initial building blocks for Little Cypress Creek, October 2006.
33
Figure 19 Initial building blocks for Black Cypress Creek, October 2006.
2.1.2.4 KNOWLEDGE GAPS AND RESEARCH PRIORITIES
At each workshop, after preliminary flow matrices were developed, participants identified knowledge gaps and
prioritized research tasks. These issues were grouped under the various instream flow disciplines and workplans
were developed to address the highest priority issues (Appendix B).
The CFP has been able to initiate work on some of these workplans in order to address high priority research
needs. This has been due to the participation in the CFP of water managers that have been willing to facilitate
some limited implementation experiments that are probably beyond what might be expected in a regular BBEST
process. To the extent possible, the workgroup has used these experiments to inform further environmental flow
analysis and overlays.
2.2 ENVIRONMENTAL FLOW ANALYSIS (OVERLAYS)
"Environmental flow analysis" “means the application of a scientifically‐derived process for predicting the response
of an ecosystem to changes in instream flows or freshwater inflows.” [§Sec. 11.002 (15)] In the CFP, the
environmental flow analysis has included all reasonably available science described in Section 2.1.1 and the
collection and additional data and development of predictive models.
Beginning in 2008, the SAC produced a number of guidance documents describing the application of overlays
relating to biology, geomorphology, and water quality (SAC 2009a‐e). Although some CFP study elements had
already been initiated when this guidance was produced, an effort was made to incorporate and, to the extent
possible, adapt the CFP to follow the direction provided in these documents. The essential direction from SAC
guidance has been to develop a preliminary flow matrix including a full regime of flow components employing
hydrological statistics as a starting point. The SAC then proposes that the BBESTs apply knowledge from other
scientific disciplines to refine this preliminary flow regime matrix by overlaying information from other disciplines.
34
The application of overlays in the CFP is described in the following sections. The section on Biology focuses on the
relationship between base flows and instream aquatic habitat. This relationship was determined based on site‐
specific data collections and instream habitat modeling. The section on Water Quality reviews existing water
quality data and known impairments, describes the relationship between flow and water quality issues of concern
and describes the judgment as to whether the recommended flow would likely cause the stream to fail to maintain
water quality standards. The section on Geomorphology is focused primarily on high flow events and their ability
to transport sediments and maintain the channel and riparian areas. Finally, the Connectivity section relates
primarily to overbank flows needed to inundate riparian and wetland areas associated with the creeks. The
primary tools used to address this issue have been the collection of elevation discharge data, modeling and
analysis using Geographic Information Systems (GIS) tools. The overlay process in the CFP was developed in several
stages. Initial overlay information was compiled in the Texas A&M report and was used to refine a subset of flow
matrix numbers at the 2005 workshop. Subsequently, fieldwork and flow experiments addressing information
needs identified at the 2005 workshop have provided additional information that has been overlain to refine the
initial building blocks. These overlay steps are detailed below.
2.2.1 BIOLOGY The SAC guidance document for conducting biological overlay provides a five‐step process for applying biological
information to refine or validate preliminary environmental flow recommendations.
STEP 1. Establish clear, operational objectives for support of a sound ecological environment and maintenance of
the productivity, extent, and persistence of key aquatic habitats in and along the affected water bodies.
The objective of the environmental flow regime recommendations is defined by the legislation and the CFP
interpretation of that legislation is provided in Section 1.2. With reference specifically to the habitat requirement
of the biological community found in the Cypress basin, the operational objective is to provide instream "habitat
conditions, including variability, to support the natural biological community" and "include ranges of flow
appropriate for wet, average and dry hydrologic conditions." (TIFP 2008) This section, Section 2.2.1, will address
instream aquatic habitat needs that are the primary function of base flows. The section on connectivity addresses
biological issues as related to riparian and watershed communities and the flows needed to maintain their health.
STEP 2. Compile and evaluate readily available biological information and identify a list of focal species.
Compilation and evaluation of readily available biological information occurred in four areas:
1. Literature survey and summary report produced by Texas A&M,
2. Review and analysis of the site specific instream flow studies that have been conducted in the basin
including correspondence and meetings with their principle authors,
3. New basin and reach level biological sampling, and
4. Review of all available historical fish collections to analyze historical trends in the fish community.
In the literature review and summary report section on aquatic fauna (Winemiller and others 2005), indicator
species were identified based on their flow dependency and whether they were of conservation or economic
concern. (Table 8)
35
Table 8 Indicator species with flow dependencies.
Scientific Name Common Name Flow Dependency
Polyodon spathula paddlefish Dependent ‐ T&E
Esox niger chain pickerel Dependent ‐ Sport
Micropterus salmoides largemouth bass Dependent ‐ Sport
Aplodinotus grunniens freshwater drum Dependent ‐ Sport
Pteronotropis hubbsi bluehead shiner Responsive ‐ T&E
Ictiobus bubalus smallmouth buffalo Responsive ‐ non T&E
Ictiobus cyprinellus bigmouth buffalo Responsive ‐ non T&E
Notropis chalybaeus ironcolor shiner Responsive ‐ non T&E
Basic life history information, especially reproduction and spawning, was provided as well as life cycle relationships
to intra‐annual variation in flow magnitude. These relationships were depicted for each of the indicator species in
figures similar to Figure 20. A complete Cypress basin species list including their general flow dependencies was
provided in the appendix to the literature survey. A general conclusion of this survey is that the Cypress basin
contains a very diverse fish community that exploits a wide range of instream habitat conditions.
Figure 20 Chain pickerel (backwater‐dependent species) life cycle relation to seasonal flow (portrayed relative to pre‐1957 median flows in
Big Cypress Creek) (Winemiller and others 2005).
In 1994, the USACE’s Engineer Research and Development Center (ERDC) produced the most comprehensive site‐
specific evaluation of the aquatic community in the Cypress basin to date (USACE 1994). In addition to the
development of one‐dimensional hydrodynamic habitat models, discussed below, habitat specific fish collections
were made at 21 sites in Big Cypress Creek from April to August 1992. Based on these and other historical
collections, fish guilds were derived from categories along two dimensions: preferred velocity (swift water, slack
water, and generalist) and spawning substrate (open water, sand and gravel, vegetation, and crevice). Habitat
suitability criteria for the dominate species within these guilds (bold in red) were developed and used in the
habitat modeling. (Figure 21) These curves allowed the Corps to model habitat responses to flows for species
representative of the various guilds.
36
Table 9 Habitat guilds for Cypress and Twelve‐mile Creek fishes, based on preferred velocities (horizontal axis and spawning substrate
(vertical axis). Evaluation species are indicated in red bold. (USACE 1994).
Lacustrine/Generalist Slack Water Swift Water
Gizzard shad American eel Skipjack herring
Mosqultoflsh Threadfin shad Emerald shiner
Cypress minnow Mimic shiner
Silvery minnow Freshwater drum
Ribbon shiner
Red shiner Redfin shiner Chestnut lamprey
Green sunfish Pallid shiner Blackspot shiner
Orangespotted Bluehead shiner Striped shiner
Bluegill sunfish Pugnose minnow Ironcolor shiner
Redear sunfish River carpsucker Sand shiner
Largemouth bass Creek chubsucker Weed shiner
White Crappie Spotted sucker Yellow bass
Black crappie Blacktail redhorse White Bass
Golden topminnow Scaly sand darter
Flier Harlequin darter
Warmouth Goldatripe darter
Redbreast sunfish Redfin darter
Dollar sunfish River darter
Longear sunfish Blackside darter
Spotted sunfish Dusky darter
Bantam sunfish
Spotted bass
Mud darter
Bowfin Spotted gar Longnose gar
Common carp Shortnose gar Black buffalo
Golden shiner Alligator gar
Brook silverside Grass pickerel
Chain pickerel
Taillight shiner
Lake chubsucker
Smallmouth buffalo
Bigmouth buffalo
Starhead topminnow
Blackstripe topminnow
Blackspotted topminnow
Inland silverside
Banded pygmy sunfish
Bluntnose darter
Swamp darter
Slough darter
Bullhead minnow Blue catfish Blacktail shiner
Black bullhead Tadpole madtom
Yellow bullhead Flathead catfish
Channel catfish Pirate perch
Cypress darter
Prefered Velocities
S
p
a
w
n
i
n
g
S
u
b
s
t
r
a
t
e
O
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e
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S
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37
Figure 21 Habitat suitability criteria. (USACE 1994).
SPOTTED
BASS
SPOTTED
SUCKER
Velocity Depth Instream Cover
BLACKTAIL SHINER
BLACKSIDE DARTER
IRON‐COLO
R SHINER
FLATH
EAD CATFISH
BLU
NTN
OSE DARTER
PICKER
LS
0.0
0.2
0.4
0.6
0.8
1.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Suitability Index
Velocity (ft/s)
0.0
0.2
0.4
0.6
0.8
1.0
0.0 2.0 4.0 6.0 8.0 10.0
Suitability Index
Depth (ft)
0.0
0.2
0.4
0.6
0.8
1.0
0 1
Suitability Index
Instream Cover
0.0
0.2
0.4
0.6
0.8
1.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Suitab
ility Index
Velocity (ft/s)
0.0
0.2
0.4
0.6
0.8
1.0
0.0 2.0 4.0 6.0 8.0 10.0
Suitab
ility Index
Depth (ft)
0.0
0.2
0.4
0.6
0.8
1.0
0 1
Suitab
ility Index
Instream Cover
0.0
0.2
0.4
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0.0 0.2 0.4 0.6 0.8 1.0 1.2
Suitability Index
Velocity (ft/s)
0.0
0.2
0.4
0.6
0.8
1.0
0.0 2.0 4.0 6.0 8.0 10.0
Suitability Index
Depth (ft)
0.0
0.2
0.4
0.6
0.8
1.0
0 1
Suitability Index
Instream Cover
0.0
0.2
0.4
0.6
0.8
1.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Suitability Index
Velocity (ft/s)
0.0
0.2
0.4
0.6
0.8
1.0
0.0 2.0 4.0 6.0 8.0 10.0
Suitability Index
Depth (ft)
0.0
0.2
0.4
0.6
0.8
1.0
0 1
Suitability Index
Instream Cover
0.0
0.2
0.4
0.6
0.8
1.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Suitability Index
Velocity (ft/s)
0.0
0.2
0.4
0.6
0.8
1.0
0.0 2.0 4.0 6.0 8.0 10.0
Suitability Index
Depth (ft)
0.0
0.2
0.4
0.6
0.8
1.0
0 1
Suitability Index
Instream Cover
0.0
0.2
0.4
0.6
0.8
1.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Suitab
ility Index
Velocity (ft/s)
0.0
0.2
0.4
0.6
0.8
1.0
0.0 2.0 4.0 6.0 8.0 10.0
Suitab
ility Index
Depth (ft)
0.0
0.2
0.4
0.6
0.8
1.0
0 1
Suitab
ility Index
Instream Cover
0.0
0.2
0.4
0.6
0.8
1.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Suitability Index
Velocity (ft/s)
0.0
0.2
0.4
0.6
0.8
1.0
0.0 2.0 4.0 6.0 8.0 10.0
Suitability Index
Depth (ft)
0.0
0.2
0.4
0.6
0.8
1.0
0 1
Suitability Index
Instream Cover
0.0
0.2
0.4
0.6
0.8
1.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Suitability Index
Velocity (ft/s)
0.0
0.2
0.4
0.6
0.8
1.0
0.0 2.0 4.0 6.0 8.0 10.0
Suitability Index
Depth (ft)
0.0
0.2
0.4
0.6
0.8
1.0
0 1
Suitability Index
Instream Cover
38
A research priority identified at the first flows workshop was to assess the current biological status of the Cypress
Basin fish assemblage. Synoptic fish surveys as well as reach‐based surveys were conducted throughout the lower
segments of Big Cypress, Little Cypress and Black Cypress Creeks. Synoptic surveys are intended to provide a
complete picture of the existing community and are therefore not limited to a strict protocol designed to produce
a consistent level of sampling effort per site. The reach‐based evaluations are intended to produce comparable
levels of effort per site thus allowing comparisons across time and space between different sampling efforts.
Reach‐based sampling following TCEQ protocols were conducted on Big Cypress Creek by the USGS and recent
comparable sampling efforts were undertaken on Black Cypress (Crowe and Bayer 2005) and Little Cypress (TSU
unpublished data). Species richness, relative abundance, diversity, and a regional index of biotic integrity (IBI) were
determined for the fish assemblages from each reach (Linam and others 2002).
Finally, regional and national museums (including the Smithsonian National Museum of Natural History, Texas
Natural History Collection (University of Texas), Tulane University Museum of Natural History, University of Kansas
Museum of Natural History and the Texas Cooperative Wildlife Collection (Texas A&M) and past monitoring
activities (primarily conducted by universities and state and federal agencies, including the recent sampling efforts
undertaken as part of the current CFP effort (USGS 2006) were surveyed. The Fishes of Texas project at the Texas
Natural History Museum was a particularly rich source of quality‐controlled data. Historical collections throughout
the basin going back to the 1950s were compiled and organized in a geodatabase. Following the approach used in
the TIFP for the SB2 priority basins (Bonner and Runyan. 2007), these data were analyzed to determine fish species
composition and abundances in Big Cypress, Little Cypress and Black Cypress Creeks and to determine if changes
through time have occurred within each. The analysis also looked for these trends based on habitat, reproductive
and trophic guilds. Given the rather patchy nature of this data through time, definitive findings are not possible,
however the preliminary finding from this analysis found that for Big Cypress several species appear to be
increasing or decreasing through time and that as a group, reproductive guilds that include riverine obligate
species appear to be declining while more generalist species appear to be increasing.
Table 10 Trends in reproductive guilds in terms of relative abundances. (Pelagophils: Obligate riverine species, broadcast‐pawn buoyant
eggs within current, Lithophils: Includes most Centrarchidae, spawn elliptical egg envelopes over rock or gravel nests.)
Reproductive Guild 1953‐54 1995 2006
Non guarders
Open Substratum
Pelagophil is 22.49 7.25 0.072
Guarders
Nest Spawners
Lithophils 7.38 42.58 56.15
After conducting this analysis, the preliminary conclusion was confirmed by the discovery of an unpublished
manuscript by Jan Hoover and Jack Kilgore at ERDC. (Kilgore and Hoover have been studying the Cypress Basin
since the 1980s.) Their report concluded that “the ichthyofauna of the Cypress Creek basin appears to have
shifted from assemblages dominated by cyprinids, percids, and cyprinidontids in the 1950s to assemblages
dominated by centrachids, other cyprinids, clupeids, and atherinids in the 1980s.” This shift in the community
from riverine specialists to generalist is a well‐documented response to altered flow regimes.
In summary the general life history information, provided by Texas A&M, for species with different flow
dependencies suggest the value of a varied flow regime with a particular need for high flow pulses and overbank
connectivity to riparian and oxbow areas. The instream flow study produced by ERDC in 1993 suggests the need
39
for habitat diversity to provide for the needs of the whole community and the historical trend analysis suggests
that riverine‐dependent species may be declining relative to a more generalist‐dominated community.
STEP 3. Obtain and evaluate geographically‐oriented biological data in support of a flow regime analysis.
This section in the SAC guidance addresses the task of producing maps that might be used to describe the various
river types that are encountered in the basin. Section 1.3 (Geographic scope) includes much of this information.
This task seems particularly important for larger basins with a wider range of ecoregions and river types. The sites
identified for the development of instream flow recommendations by the CFP all fall within the same ecoregion
and the group concluded that they are sufficiently similar that different sites do not require the development of
analysis that are fundamentally different.
However the CFP is in the enviable position, given the time and resources that have been devoted to this project
and the long history of instream flow evaluation conducted in the Cypress basin, of having site‐specific habitat data
including new data that was collected as part of this study and data collected previously as part of earlier studies in
the basin.
Among the knowledge gaps and research priorities identified during the development of the preliminary flow
recommendations were the need to assess instream habitat availability at different low‐flow levels. Beginning in
2006, the USGS led the field effort to collect data to fill in these knowledge gaps (USGS field work and analysis also
included investigations related to geomorphic characterizations and quantification of riparian connectivity
discussed below).
In October 2005, a site reconnaissance was undertaken to determine the location of adequate points of access to
Big Cypress Creek over this segment, and to complete a rapid evaluation of habitat conditions and geomorphic
features of the channel. The reconnaissance provided critical information in support of the selection of a set of
candidate sites for baseline assessment of reach‐based geomorphic features, fish assemblages, and for the
installation of pressure transducers for monitoring stage and water temperature. Three sites were selected on Big
Cypress upstream of Jefferson. An additional site downstream of Jefferson, as well as a site on Black Cypress, was
added subsequently.
At each site, a channel reach was established based on a multiple of mean wetted channel width (20X) at low flow
(Leopold 1964 and Fitzpatrick and others 1998). The upstream and downstream extents of each reach were
selected to include at least two of each geomorphic channel units (GCUs) such as riffle, runs, or pools. GCUs are
fluvial geomorphic descriptors of channel shape and scour patterns widely used in stream habitat assessments
(Orth 1983; Ohio Environmental Protection Agency 1989). The GCU sequence was duplicated at each reach to
facilitate comparisons between sites.
40
Figure 22 Map of USGS study sites.
Habitat and geomorphic data were collected at the segment, reach and transect scales (Table 11). At the segment
scale (Big Cypress and Black Cypress segments), length and curvilinear length were measured and from these
measures, gradient and sinuosity were determined (Fitzpatrick and others 1998). In addition, side‐slope gradient
was measured at ten regularly spaced intervals to provide an indication of the variability in the valley slope over
the length of the segment. At the four study reaches on Big Cypress (BC00, BC01, BC02, and BC03) and the one on
Black Cypress (BLCK01), water‐surface gradient and the sequence, type and length of GCUs were determined. The
horizontal and vertical extent of physical features such as undercut banks and woody snags were also surveyed.
Within each study reach, eleven cross‐section transects were distributed equidistant from the upstream to the
downstream. Each transect extended from the high‐bank terrace on one bank to an equivalent height on the
opposite bank. For each transect, a number of measurements, including bank slope and bank height, were
recorded. Within the stream and in alignment with each transect, stream depth, velocity, bed substrate
composition, and habitat cover were measured at three points including the channel thalweg, and two additional
points each one one‐half the distance from the thalweg to the water’s edge of each bank.
41
Table 11 Segment, reach, and transect‐scale geomorphic and stream habitat measures.
Segment Reach Transect (n = 11 per reach)
Segment length (m) Reach length Bankfull height
Curvil inear segment length (m) Curvil inear reach length Bank slope
Segment gradient Reach gradient Bankfull width
Side‐slope gradient GCU type and length Bank vegetative coverage
Thalweg profile Wetted channel width
Depth
Velocity
Dominant and sub‐dominant substrate
Habitat cover
Canopy closure
Riparian buffer width and density
A number of site‐specific instream flow studies have been conducted in the Cypress basins since the early 1980s.
These studies generally followed the Instream Flow Incremental Methodology (IFIM), which produces predictive
relationships between flow and an ecological response, namely the amount of habitat available to specific species
generally selected to represent larger habitat guilds. There were two studies undertaken simultaneously on Little
and Black Cypress (Cloud 1984, USACE 1987) in response to reservoir proposals on those tributaries and a more
recent one to evaluate a proposal to extend navigation on Big Cypress (USACE 1994).
Figure 23 Map of previous Instream flow study sites.
The results of these studies were used in an overlay process to inform the development of the preliminary building
blocks (Section 2.1.2.1). However, these studies were not specifically designed to address the same objective as SB
3, and in fact, the methods and findings reached by these studies are not entirely consistent with one another.
The science of instream flows, while rooted in the same basic approaches to instream habitat modeling, has also
evolved in the last two decades. Perhaps just as important as the findings from these studies, is the fact that much
42
of the original data used to conduct these studies including cross‐section surveys, flow versus water surface
elevation rating curves, habitat suitability criteria and the computer input files for the 1‐dimensional Physical
Habitat Simulation Models (PHABSIM) is available and has been reviewed and in some cases reanalyzed as part of
the CFP.
STEP 4. Parameterize the flow regime hydrological analysis using ecological and biological data.
The preliminary hydrologic analysis for Big Cypress was conducted by Texas A&M using the Indicator of Hydrologic
Alteration (IHA) software. IHA is a forerunner to the HEFR, the hydrological statistics tool used in other BBESTs as
part of SB 3. While both of these tools include functions not available in the other, the results produced by IHA
appear to be very similar to what would have been produced had HEFR been available. Texas A&M provided the
workshop participants complete IHA results including statistics for the pre‐Lake O' the Pines period (1924‐1936)
and the more recent period (1980‐2003). A similar analysis was produced based on gage data for Little and Black
Cypress for the second flows workshop. The workshop participants agree to base the preliminary building blocks
on the Pre‐impact period for Big Cypress. This is consistent with TIFP and most of literature related to the science
of instream flows. The technical approach of the TIFP, much of which has since been adopted in the SAC technical
guidance documents, received a favorable external review by the NAS (NRC 2005). The NAS (2005) report noted
that "state‐of‐the‐science programs use natural flow characteristics as a reference for determining flow needs."
Discussions of analysis provided in the summary report (Winemiller and others 2005), focused on the differences
between the pre‐ and post Lake O' the Pines records. Since there have been no major flow quantity alterations on
Little and Black Cypress, the entire period of record was used for each of these gages.
The approach utilized in the CFP follows current worldwide consensus regarding theory and tools for
understanding and managing flow regimes. Over the last 30 years, river scientists have learned quite a bit about
the functioning of rivers and the influence of flow regime on aquatic organisms, geomorphology, and other
characteristics of rivers (NAS 1992; Gordon et al. 2004; Dyson et al. 2003; NRC 2005; Thorp et al. 2006; Locke et al.
2008). Through extensive research, river scientists and biologists have developed a “natural flow regime
paradigm” which states that in general, the ecological integrity of river ecosystems depends on their natural
dynamic character, especially their natural flow variability. River flow regime, which many ecologists consider the
key driver of river ecology and function, influences habitat, biota, water quality and geomorphology of the rivers
(Poff et al. 1997; Bunn and Arthington 2002; Cushing et al. 2006; Poff and Zimmerman 2009). For example, Bunn
and Arthington (2002) conducted a literature review focused around four key principles to highlight the important
mechanisms that link hydrology and aquatic biodiversity and to illustrate the consequent impacts of alterations to
natural flow regimes. Tables 12‐15 summarize their findings.
43
Table 12 Summary of biotic responses to altered flow regimes in relation to flow‐induced changes in habitat (principle 1). (Bunn and
Arthington 2002).
Table 13 Summary of life history responses to altered flow regimes (principle 2). (Bunn and Arthington 2002).
44
Table 14 Summary of biotic responses to loss of longitudinal or lateral connectivity (principle 3). (Bunn and Arthington 2002).
Table 15 Summary of biotic responses to altered flow regimes in relation to invasion and success of exotic and introduced species (principle
4) (Bunn and Arthington 2002).
This extensive body of research has established strong support for the links between biological processes and
aspects of flow variability. The safest and simplest approach to insure that both natural variability and threshold
conditions are restored or conserved is to mimic the natural flow pattern as closely as possible including variability
patterns (wet, dry and average years, seasonal), and associated duration and magnitude of flows. One way of
doing this, which the CFP utilized, is by using software such as IHA and HEFR that provides quantifiable endpoints
that describe this distribution and recommends flow regimes that attempt to duplicate these endpoints as closely
as possible.
These types of desktop hydrologic tools have been widely utilized in this application across the world. In one
review of the use of such tools, Ogden and Poff (2003) reviewed 171 hydrologic indices from 420 sites across the
USA and showed that the IHA method successfully characterizes all the major components of the flow regime. The
results from their study showed that the IHA method adequately represented the majority of the variation
explained by the entire population of 171 indices and thus captured the majority of the information available.
Furthermore, the IHAs represent almost all of the major components of the flow regime, and therefore provide a
good balance between objective selection of high information indices and accessibility in terms of computation.
STEP 5. Evaluate and refine the initial flow matrix.
Flow recommendations were evaluated at a third flows workshop in October 2008, based on analysis of the recent
data collection efforts and of the physical habitat models available from previous studies. Data collected by the
USGS in 2006‐07, indicates that the base flow recommendation provide a range of habitat diversity relative to
available instream structure. The dominant instream structures in the system are snags and cypress knees. During
dry conditions, the lowest flows recommended are 8‐13 cfs (Jul‐Sep). Water surface elevations were surveyed at
45
flow of 16.7 cfs and compared to surveys of instream snags (Figure 24). This comparison indicates that that these
low flows provide good access to this patchy but important instream habitat. In the range of flows from 40‐90 cfs,
the base dry targets for October to February, these snags would begin to be inundated.
Figure 24 Comparison of water surface elevations produced by base dry flows to instream structure (snags) at BC03.
During wetter conditions, the dominant instream structure is cypress knees, which are only slightly inundated at
low flows and progress through a full range of inundation as flows increase to the highest base flow
recommendation of 536 cfs (Figure 25).
46
Figure 25 Comparison of water surface elevations produced by base wet flows to instream structure (Cypress knees) at BC03.
Physical habitat models were used to evaluate the availability of preferred habitat as defined by velocity, depth
and instream cover suitability criteria. The primary output from these model simulations are Weighted Usable
Area (WUA) versus flow curves, which depict availability of preferred habitat conditions for species representative
of the habitat guilds present in the stream. Figure 26 and Table 16 present WUA results for BG 02. At the third flow
workshop in December 2008, the working group reviewed results from habitat models for other sites including two
more on Big Cypress (BG 1 and BG 3) and two on Little (LT 3001 and LT 154) and one on Black (BL). For the sites on
Big Cypress monthly percent of maximum WUA was also calculated for building blocks derived solely from the
hydraulic analysis (IHA) and building blocks that would have resulted from statistics derived from the flow record
after Lake O' the Pines (Post). These results are provided in Appendix C.
47
Figure 26 Weighted usable area versus discharge at BG 02.
Based on the WUA results, the amount of habitat (expressed as a percent of the maximum possible area) produced
by the initial building blocks is presented in Table 16. The table is color coded to provide a quick visual to the
percent of maximum available habitat showing greater than 90% in green, 75‐90% in blue and 50‐75% in red.
Based on these results we see that very little habitat is available for any of the fish guilds at the low summer (Jul‐
Sep) base dry flows. Conversely, good to excellent conditions are produced by the base dry targets for much of the
rest of the year. During average years, there is somewhat more available habitat in the summer and a slight
decrease in the rest of the year as compared to the dry conditions targets. The wet base flow targets produce the
most habitat in the summer but these higher flows tend to decrease available habitat in the rest of the year
(relative to dry and average base flows). Similar results were produced by considering an alternative period of
record, one more reflective of current management of Lake O' the Pines, to develop a flows matrix. It should be
noted that while a great deal of quantitative results from a predictive model was reviewed by the working group,
there is no formula for determining exactly how to select a flow recommendation from these results.
0
10000
20000
30000
40000
50000
60000
70000
0 200 400 600 800 1,000
Habitat (ft2/1000ft)
Discharge (cfs)
SPOTTED SUCKER SPOTTED BASS PICKEREL
BlUNTNOSE DARTER FLATHEAD CATFISH IRONCOLOR SHINER
BLACKSIDE DARTER BLACKTAIL SHINER
48
Table 16 Percent of maximum habitat BG 02 produced by building blocks recommended flow.
At the third flows workshop (October 2008), participants reviewed the information presented in Figure 26 and
Table 16 and addressed the following issues.
Does the change in habitat based on pre vs. post LOP conditions suggest a refinement?
Should the group re‐evaluate modifications to the flow matrix from IHA outputs that were made based on
reference to other studies?
Should there be refinements made to compensate or mediate for habitat for fishes that appear to be
declining?
SLACK WATER SWIFT WATER
SAND AND GRAVEL VEGITATION CREVICE SAND AND GRAVEL CREVICE
Dry
SPOTTED
SUCKER
SPOTTED
BASS PICKEREL
BlUNTNOSE
DARTER
FLATHEAD
CATFISH
IRONCOLOR
SHINER
BLACKSIDE
DARTER
BLACKTAIL
SHINER
Jan 90 99% 98% 100% 100% 85% 100% 100% 86%
Feb 90 99% 98% 100% 100% 85% 100% 100% 86%
Mar 218 92% 98% 90% 94% 75% 83% 79% 100%
Apr 198 94% 99% 92% 94% 76% 86% 83% 100%
May 114 100% 100% 99% 100% 83% 99% 98% 92%
Jun 49 82% 85% 89% 87% 77% 85% 87% 64%
Jul 13 18% 20% 21% 16% 20% 21% 22% 10%
Aug 8 9% 10% 10% 7% 9% 11% 11% 4%
Sep 8 9% 10% 10% 7% 9% 11% 11% 4%
Oct 40 70% 77% 82% 73% 70% 74% 75% 53%
Nov 90 99% 98% 100% 100% 85% 100% 100% 86%
Dec 90 99% 98% 100% 100% 85% 100% 100% 86%
Avg
Jan 268 86% 96% 83% 91% 72% 79% 69% 97%
Feb 347 78% 92% 69% 85% 71% 72% 58% 90%
Mar 390 74% 90% 66% 81% 70% 69% 55% 87%
Apr 330 79% 93% 72% 86% 71% 74% 60% 91%
May 150 99% 100% 97% 98% 79% 95% 93% 98%
Jun 79 97% 97% 100% 99% 85% 99% 99% 82%
Jul 35 59% 68% 72% 61% 64% 65% 64% 45%
Aug 40 70% 77% 82% 73% 70% 74% 75% 53%
Sep 40 70% 77% 82% 73% 70% 74% 75% 53%
Oct 40 70% 77% 82% 73% 70% 74% 75% 53%
Nov 90 99% 98% 100% 100% 85% 100% 100% 86%
Dec 117 100% 100% 99% 99% 82% 99% 98% 93%
Wet
Jan 396 74% 90% 65% 80% 70% 69% 54% 87%
Feb 500 69% 88% 61% 71% 69% 66% 51% 81%
Mar 536 68% 87% 60% 69% 69% 65% 51% 79%
Apr 445 72% 89% 63% 75% 69% 67% 53% 84%
May 264 87% 97% 84% 92% 73% 79% 70% 97%
Jun 140 99% 100% 98% 98% 80% 96% 95% 97%
Jul 70 95% 95% 98% 98% 84% 97% 98% 78%
Aug 41 71% 78% 82% 74% 71% 75% 76% 54%
Sep 40 70% 77% 82% 73% 70% 74% 75% 53%
Oct 49 82% 85% 89% 87% 77% 85% 87% 64%
Nov 94 99% 99% 100% 100% 84% 100% 100% 87%
Dec 275 85% 96% 82% 91% 72% 78% 68% 96%
49
Are all three base flow levels (wet/average/dry) necessary?
Are the base flows needs upstream and downstream of Jefferson the same?
Does the analysis suggest other areas of concern?
The discussion first focused on if and how this analysis could be used to validate or refine the preliminary flow
recommendations. Generally, the analysis showed that the building blocks provide variability in stream habitat
conditions. Although the area of some habitat types would be relatively lower than others, this was assumed to be
reflective of the natural habitat conditions of the stream, which the recommendations are intended to protect.
One clear conclusion from the analysis was that habitat in the lower reach of Big Cypress Creek is less sensitive to
changes in flow than in the upper reach.
The participants agreed that this type of evaluation is useful in providing insight into what the base flow
recommendations would produce in terms of instream habitat. However, given the lack of any outstanding
concerns arising from this analysis, tempered by uncertainty associated with biological data and hydrodynamic
models developed 15‐25 years ago, the workgroup concluded that the results of this evaluation supported the
basic approach taken for low flows in the building blocks for the three rivers and that the results did not suggest
further revisions to the approach or prior recommendations for those flows.
2.2.2 GEOMORPHOLOGY Geomorphic investigations are conducted as part of instream flow studies to evaluate how the movement and
transport of sediments maintain river channels. The most widely referenced, though not universally accepted,
hypothesis that addresses this issue is that river channels are in a state of dynamic equilibrium that is governed by
a number of factors, including flow rate, sediment characteristics and channel morphology that interact and
respond to adjustment from one another (Lane 1955). Many studies suggest that channel instability can result in
significant deleterious impacts including:
Increased erosion,
Undercutting banks,
Less succession riparian vegetation which can lead to reduced loading of course woody debris, an
important component of instream habitat,
Straightening and narrowing of channels,
Removal of hydraulic controls for upstream reaches, inducing scour of upstream riffles,
Typically wider, shallower stream beds, leading to increased temperature,
Modification of pool‐riffle distribution and
Altered flow paths.
Given the multiple interactions that can affect sediment transport, guidance provided by the SAC has been to use
effective discharge as an indicator of sediment transport. The idea being that as long as the effective discharge is
not changed dramatically, then there is reason to suspect that sediment transport processes will continue to
function as they should. The basic framework is to:
1. Describe existing or historical conditions and calculate effective discharge,
2. Develop a reasonable approximation of a future hydrograph resulting from the implementation of the
flow recommendations, and
3. Evaluate potential impacts resulting from the changed flow regime.
50
Information provided in the literature survey addressed the first issue and provided an evaluation of the change in
effective discharge based on the closure of Ferrells Bridge Dam and filling of Lake O' the Pines. Based on this
analysis the working group recommended as part of the initial building blocks, several high flow events at the
effective discharge (6,000 cfs). At the same time, they recognized that these estimates would benefit from
targeted research including:
Collection of baseline geomorphologic data to assess the responses during and following flow releases
(including sediment characteristics, channel cross‐section and general assessment of channel condition),
and
Estimate sediment budget and develop better characterization of sediment composition along entire
creek.
These two tasks address two of the functions that relate geomorphic processes to a sound ecological environment.
The first task directly addresses channel characteristics that are maintained by the current sediment transport.
This task is being addressed as part of a contract with the USGS that is assessing channel morphology in the
regulated segment of Big Cypress Creek and compare these conditions with the channel morphologies observed in
the unregulated Little and Black Cypress Creeks. Some of the data and analysis conducted under this effort is
discussed in Section 2.2.1. The second task evaluates the ability of the stream flow to move sediments through
the system. This ability was quantified by a calculation of stream power and effective discharge based on available
information provided in the summary report. (Bankfull flow is often used as an initial estimate of effective
discharge. Refinements to the bankfull estimates based on field studies are address below under connectivity in
Section 2.2.4.) The SAC provided guidance on an approach to refine these estimates by collecting sediment
samples and undertaking a modeling exercise (SAM). While a scope of work was developed to perform these
tasks, the work has yet to be completed. However, it is expected that a more thorough evaluation of effective
discharge will be completed prior to the next flows workshop.
2.2.3 WATER QUALITY Although the initial building blocks for Big Cypress did not explicitly consider water quality issues, the absolute
minimum flows (summer dry base) were revised to provide a conservative estimate of flows necessary to maintain
water quality standards. The water quality concerns have been the focus of the development of building blocks for
Caddo Lake, with the proposal that lake levels be lowered periodically for management of nutrients and
sediments.
The SAC guidance on the application of water quality overlays to refine preliminary flow matrices includes the
following steps:
Identifying current conditions and trends in water quality, mainly in relation to the state water quality
standards,
Evaluating the relationship between flow and the water quality parameters of concern, and
Determining whether changes are needed to the building blocks to address water quality issues.
The first step was included in the literature survey (Winemiller and others 2005) and in the review of the water
quality impairment list (303d) included in the Cypress Basin Highlights report (NETMWD 2010). (Section 2.1.1.3).
Of these identified water quality issues, dissolved oxygen (DO) has the greatest potential for impact through
prescriptive flow building blocks because increased velocity provides re‐aeration and mixing to increase DO
concentration.
51
The dissolved oxygen concentration of a water body has historically been considered one of the most important
water quality parameters to measure. High dissolved oxygen concentrations have been linked to high aquatic life
use, and low dissolved oxygen concentrations have been linked to low aquatic life use. Dissolved oxygen
concentrations in water can be affected by many factors, especially water temperature and rates of re‐aeration. In
streams, re‐aeration rates are often closely associated with stream flow. TCEQ considers Black Cypress Bayou in
the Big Cypress Watershed as a least‐impacted stream and reference stream within the South Central Plains
ecoregion because of limited human disturbance and minimal point and non‐point pollution sources. A study of
Black Cypress Bayou by TCEQ during 2000 and 2001 was conducted to determine how the flow of the stream
related to the aquatic life of the stream (Crowe and Bayer 2005). During both summers, the flow of the stream was
below 7Q2 and flow intermittently with perennial pools. During August of 2001, 24 hr dissolved oxygen means
were generally below 3 mg/L which is lower than the Texas Surface Water Quality Standard. Despite low dissolved
oxygen concentrations during this critical period, the aquatic life was rated as high to exceptional. A Rapid
Biological Assessment (RBA) of the benthic macroinvertebrate community scored in the intermediate to high
categories, while an Indicators of Biotic Integrity (IBI) of the fish community scored in the high to exceptional
categories. The report concluded that the fish assemblage in the watershed has the ability to withstand periodic
low summertime dissolved oxygen conditions of short durations.
Given the finding that naturally occurring low DO conditions do not appear to have significant detrimental effect
on the biological community, the CFP did not include a category to the building blocks for subsistence flows,
though this issue was discussed at some length. There was considerable discussion that very low flows occur
naturally in the unregulated streams and the general consensus that these conditions are an acceptable
component of the sound environment of this system. Note the workgroup did recommend minimum base flows of
5 and 4 cfs for Little and Black Cypress to ensure that the frequency of occurrence of pools becoming disconnected
is not increased. The workgroup also decided to increase the minimum flow recommendation in Big Cypress Creek
up from 6 cfs to the 7Q2 value of 8.2. This was done to provide a slightly more conservative estimate of the flow
needed to maintain the DO standard in this segment.
Watershed Protection Plan
Concerns raised about the water quality impairments in the CFP led to an agreement with TCEQ for the
development of a Watershed Protection Plan (WPP) in 2006 to address water quality issues in a more
comprehensive process. The Northeast Texas Municipal Water District has served as the watershed coordinator for
the project. The WPP has provided new sources of information. It also helped expand the participation by scientist
and stakeholders in the CFP. There has been a significant effort to coordinate the work of the WPP and CFP. The
CFP, for example, serves as the hydrology work group for the WPP, which has two other work groups.
While there has been important collaboration, the two processes are somewhat different. Both provide for
participation by scientists and stakeholders, but the work of the WPP is guided to a larger degree by the
stakeholder goals and TCEQ’s interests. Thus, at TCEQ’s request, the WPP has not been used to address mercury
impairments. It has instead focused on bacteria and DO impairments. During the first two years of the WPP, work
focused on identifying potential short‐term solutions to the problems of giant salvinia (Salvinia molesta); a floating
invasive aquatic plant, first discovered in Caddo Lake in 2006.
In any case, water quality problems in most of the watershed have appeared to be more dependent upon sources
than on flows. The solutions, therefore, may depend more upon reductions in the loading of pollutants than on
flow regimes. The possible exception is Caddo Lake where flushing flows and lake level adjustments may be
52
needed. The WPP process may provide a basis for refinements, but the preliminary modeling of loadings, flows and
impacts together with proposals for load reductions will not be available until late 2010.
The WPP and CFP have recognized the need to evaluate changes to pulse and flood flows and in levels of Caddo
Lake for water quality and control of aquatic vegetation in the Lake. The evaluation of options for changes to the
dam at Caddo Lake will be part of a new study begun by the U.S. Corps of Engineers in 2010. That work will not be
completed, however, for several years. Changes to the dam and options for significant lake lowering are not likely
to be made for many years.
2.2.4 CONNECTIVITY The issue of riparian and wetland connectivity is of great importance in the Cypress Basin. The creeks in the basin
support valuable bottomland hardwood and Cypress forests (Figure 27). As noted in the biological section, many
of the fish that inhabit this area rely on access to riparian and watershed areas for part of their life cycle.
Figure 27 Bottomland Hardwood and Cypress forests associated with Cypress Creeks.
Estimates of the flows needed to maintain this connectivity formed a critical component of the initial building
blocks and evaluation of these estimates has been the focus of considerable effort over the last several years.
These efforts have included experimental releases from Lake O' the Pines to test whether the flow prescribed in
the initial building blocks achieves desired overbank results, refinements to water surface elevation models (HEC‐
RAS) to produce coarse but larger scale inundation maps, and, most recently and still in process, work analyzing
high resolution satellite imagery to develop relationships between flow and area inundated and thus predict
ecological benefits of higher flows to spatially explicit wetland communities.
53
Collection of high flow and stage data was the primary tool used to evaluate the high flow targets. The first step in
this process was to install pressure transducers, which measure water elevation, at ten locations on Big Cypress
and three each on Little and Black Cypress.
Figure 28 Pressure Transducers installed to measure water surface elevations.
These instruments remained in place for up to a full year on Big Cypress and captured a full range of flows. They
were specifically deployed in advance of experimental releases made from Lake O' The Pines to test the overbank
and connectivity that results from high flow events. From January 25th to February 3rd, 2007 the Corps stepped up
releases from about 100 cfs to 500 cfs to 1800 cfs. (Figure 29)
54
Figure 29 Flow rate measured at nearby gage during experimental releases from Lake O' the Pines.
Releases were held constant for several days to allow for a relatively static flow condition past each of the pressure
transducers allowing the direct observation of water surface stage to flow rate. Throughout the rest of the year,
the PTs recorded flow up to the maximum release from Lake O' the Pines equal to 3,000 cfs. After processing the
raw data and georeferencing their exact positions, a longitudinal profile of water surface elevation for a range of
flows was developed. (Figure 30)
55
Figure 30 Longitudinal profile of water surface elevation in Big Cypress Creek.
This data was then used to produce an inundation map based on an available digital elevation model of the
watershed. (Figure 31) These results were consistent with observations made during the experimental releases.
Namely, that riparian areas in the segment of Big Cypress upstream of Jefferson are inundated at flows well below
the initial overbank estimate of 6,000 cfs. Downstream of Jefferson where the channel is much wider and deeper,
there is no overbank until below the confluence with Little and Black Cypress.
LOP
BC03
COE04
BC02
COE07
COE09
BC01 BCJEFF BC00 COE16COE20
165.00
170.00
175.00
180.00
185.00
190.00
195.00
200.00
5863687378
Water Surface Elevation
River Mile
100.00
500.00
1750.00
3000.00
56
Figure 31 Area inundated at 3,000 cfs release.
Additional work to more precisely quantify riparian connectivity is currently underway on two fronts. First, as part
of the work undertaken by the USGS and the Corps of Engineers, 24 cross‐section s were surveyed in Big Cypress
Creek. These along with the PT data are being used to calibrate a HEC‐RAS model that will be used to make a more
accurate prediction of water surface at flows not observed directly and potentially to facilitate additional analyses
related to sediment transport and water quality. Finally, a study has recently been initiated similar to the work
done by the Sabine Neches BBEST to analyze satellite imagery and more directly relate inundation areas to
wetland plant communities.
2.3 ENVIRONMENTAL FLOW REGIME RECOMMENDATION
The building blocks developed at the first two flow workshops (May 2005, October 2007) were revised at the third
workshop in December 2008 based on additional data that had been collected and the environmental flow
(overlays) analysis that had been conducted. With respect to the recommendations for Big Cypress Creek, the
consensus was to largely adopt the preliminary matrices. It is important to note that these values had already been
modified from a purely hydrologic analysis in considering the other riverine disciplines as part of the literature
survey and summary report. Nonetheless, the subsequent additional environmental flow analysis did result in the
modification of several recommended flows. Values in red are those that were not calculated as part of the
hydrologic analysis using IHA, but are refinements and adjustments to the building blocks based on the application
of overlay analysis. Some these adjustments were made in the development of the preliminary building blocks by
considering the information presented in the literature survey, while others were modified based on the analysis
that has been preformed subsequently.
57
Figure 32 Big Cypress Creek Flow Regime Recommendation.
With respect to base flows, the workgroup agreed that the results of the analyses performed as part of the
biological overlay (Section 2.2.1) confirmed the basic framework of developing a range of base flow
recommendations based primarily on historical pre‐development flow records. Generally, the analysis showed
that the building blocks derived primarily from pre‐impact flow records, provide variability in stream habitat
conditions. Although the area of some habitat types would be relatively lower than others, this was assumed to be
reflective of the natural habitat conditions of the stream, which the recommendations are intended to protect.
One conclusion from the analysis was that habitat in the lower reach of Big Cypress Creek is less sensitive to
changes in flow than in the upper reach. This is due to the fact that Big Cypress Creek has been channelized and
deepened downstream of Jefferson. While flow recommendations derived from a pre‐development period of
record appear to be supportive of ecological functions in river segments that have not experienced significant
structural modifications (e.g. Big Cypress upstream of Jefferson and the unregulated tributaries), these flows may
not be sufficient to restore this variability to a segment that has undergone significant structural modifications.
The workgroup agreed that this type of evaluation is useful in providing insight into what the base flow
recommendations would produce in terms of instream habitat, however there was also some reluctance to make
adjustment to the building blocks based on biological data and habitat models that are 15‐25 years old, without
first providing a more recent validation of these results. A Clean River Program special study has since been
initiated that will include mesohabitat specific sampling to further validate or refine results from these models.
58
Regarding low flows, the workgroup decided to adopt a slightly more conservative approach to ensure that for dry
conditions in Big Cypress Creek during July through September flows are adequate to protect water quality. The
workgroup decided to adopt the 7Q2 flow value developed by the state water quality standards and permitting
system equal to of 8.4 cfs for this segment of Big Cypress Creek until additional data or analysis indicates another
value should be used. This is higher than the low flow proposed in the building block of 6 cfs. For Little and Black
Cypress Creek the absolute minimums were adjusted up from the purely hydrologic (IHA) analysis, to 5 and 4 cfs
respectively.
Field work and other analysis was performed by USGS to evaluate the preliminary high flow recommendations for
Big Cypress Creek. The analysis of observed high flow releases from Lake O' the Pines by the USGS (Section 2.2.4)
resulted in changes to the recommendation for pulse flows for Big Cypress Creek. This analysis indicated that
bankfull flows occur below 3,000 cfs. The flows needed for bankfull conditions also changed from the upper reach
(generally above Jefferson) to the lower reach (below Jefferson). While valuable wetland resources depend on
overbank flows in the lower segment, it seems clear that for the near future these events will be driven by inflows
from the unregulated Black and Little Cypress Creeks. The workgroup decided to change the larger high flow pulse
from 6,000 cfs to 2,500 cfs, which appears to provide a good approximation of bankfull flow in the upper reach.
The lower flood flow was then changed to a range from 3,000 cfs to 10,000 from the prior range of 6,000 to 10,000
to reflect that there was good connectivity occurring at flows as low as 3,000 cfs. It is worth noting that while
these adjustments reflect new understanding related to overbank flows, additional analysis will be necessary to
evaluate their effect on sediment transport.
Concern was also raised about the lack of building blocks for James Creek and a number of small streams in the
basin. Because these streams do not have gages, it was agreed that the IHA approach used for Big, Little and Black
Cypress Creeks could not be applied. Instead, the group agreed that flow regimes for these creeks should be based
on the building blocks for Big Cypress Creek with a proportional adjustment for the different sizes of the
watersheds.
In addition to describing the flow magnitudes necessary to achieve desired ecological outcomes, an SB 3 flow
standard, and ultimately the rule developed by TCEQ, should also include the attainment frequencies at which the
various flow components must be met. Although attainment targets were not explicitly defined by the CFP, the
guiding principal behind the project, as discussed in Section 2.2.1, is the natural flow paradigm, which says that the
best way to maintain a sound ecological environment is to mimic the natural flow pattern as closely as possible
including variability patterns (wet, dry and average years, seasonal), and associated duration and magnitude of
flows. With that concept in mind, historical frequencies of the various recommendations were calculated as well
as the predicted attainments under potential future flow scenarios. A discussion paper describing the process in
determining attainment goals and the issues that need to be considered as part of this process was prepared and
presented at the December 2008 flows workshop and it is included in Appendix D. Appendix E (also presented at
the December 2008 workshop) extends further into the realm of implementation with an example of how the
various flow conditions (dry, average and wet) could be triggered.
The most significant revision to the recommendations relates to the adoption of narrative standards for Black and
Little Cypress Creeks; a concept which had been proposed in the 2006 workshop. The confluences of Little and
Black Cypress Creek with Big Cypress Creek are just upstream of Caddo Lake and high flows in Black and Little
Cypress can provide relatively high flows to the wetlands and lake, even with the reduced flows from Big Cypress
due to the existence of Lake O’ the Pines. These high flows are needed for inundation of wetlands associated with
Caddo Lake. Although no specific numbers or limitations were proposed by the workgroup, a consensus was
reached that a significant proportion the entire population of overbank flows, not just those at the specific
59
magnitudes depicted in the building blocks, should be excluded from future diversions. Consistent with the
resource values of the two tributaries, a greater level of protection was stipulated for the regionally least impacted
stream, Black Cypress, than for the relatively more modified Little Cypress.
While not done before or at the December 2008 flows workshop, several options exist for a quantitative approach
for implementing these narrative standards based on riverine and wetland science. This is an area where the line
between pure science and the value that stakeholders associate with these resources is less sharp. In any case,
after the 2008 meeting, an example of an implementation approach was developed and it is provided in Appendix
F. While developed after the third flows workshop, it has been reviewed by some workgroup members. It is just
one example of how a narrative standard could be implemented.
3 CONCLUSIONS Among the many similarities shared by the SB3 and SPR approaches is the acknowledgement that data limitations
and incomplete understanding of ecological processes leads to the development of imperfect environmental flow
recommendations. In order to address these shortcomings both of these processes have adopted the approach of
employing adaptive management so that new information can be incorporated into subsequent
recommendations. The adaptive management process is developed in several steps including the establishment of
a schedule to review recommendations, the application of targeted research to gain a higher level of certainty in
the recommended flows, and development of ecological indicators to monitor the efficacy of the
recommendations. In the SB 3 legislation these steps are required as part of the development of a workplan.
[§Sec. 11.02362 (p)] The CFP has established a three‐year schedule to review the current recommendations, by
which time they should have additional information from targeted research including:
1. Water quality work from the Watershed Protection Plan,
2. Mesohabitat specific monitoring of recommended base flows via a CRP special study,
3. Application of sediment transport modeling (SAM),
4. Analysis of digital imagery data to relate areas of wetland inundation to flows,
5. Additional experimental releases from Lake O’ the Pines,
6. Application of daily timestep reservoir operations model to evaluate impact of flow targets on
reservoir storage, and
7. New projections on water needs in the region by the Region D Water Planning Group.
Finally, the CRP is in the process of establishing ecological indicators and process for evaluating the efficacy of the
flow recommendations. An early draft of this effort is included in Appendix G.
60
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LIST OF AVAILABLE APPENDICES Appendix A Summary of the Process
Appendix B Data Collection and Research Priorities
Appendix C Habitat Modeling
Appendix D Attainment Targets
Appendix E Implementation Example
Appendix F Narrative Standards
Appendix G Indicators (in progress draft)
DRAFT
1
CYPRESS FLOWS PROJECT ENVIRONMENTAL FLOWS REGIME AND ANALYSIS
APPENDICES
LIST OF AVAILABLE APPENDICES Appendix A Summary of the Process
Appendix B Data Collection and Research Priorities
Appendix C Habitat Modeling
Appendix D Attainment Targets
Appendix E Implementation Example
Appendix F Narrative Standards
Appendix G Indicators (in progress draft)
APPENDIX A SUMMARY OF THE PROCESS {This document is in the format that was used throughout the Cypress Flow Project. Much of the information has been include in the final Environmental Flow Regime and Analysis Recommendations Report.}
REPORT ON THE
ENVIRONMENTAL FLOWS PROJECT FOR THE CYPRESS RIVER BASIN
A Report of the The Flow-Ecology Project
Sponsored by the Nature Conservancy–U.S. Corp of Engineers Sustainable Rivers Program and the Caddo Lake Institute
& The Hydrology Workgroup
of the Watershed Protection Plan for the Caddo Lake Watershed Coordinated by the North East Texas Municipal Water District
Interim Report: November 2008 Draft Final February 2009, updated August 2010
© John Winn
The Sponsors acknowledge and thank all those who have participated in the Project and especially those whose funding has helped pay for the work, including the Coypu Foundation, Magnolia Charitable Trust, the Meadows Foundation, American Electric Power, the North East Texas Municipal Water District, Texas Commission on Environmental Quality, the U.S. Army Corps of Engineers, the U.S. Environmental Protection Agency, the Fish and Wildlife Service Program on Wildlife Without Borders—Mexico, Latin America and the Caribbean, and the U.S. Geological Survey.
TABLE OF CONTENTS
Summary 1 A Science and Stakeholder Based Process 2 The Initial Consensus to Pursue the Project 2 Identifying Scientists and Stakeholders 3 Literature Review and Summary Report 3 First Flow Workshop - May 2005 4 Building Blocks for Big Cypress Creek 5 Building Blocks for Caddo Lake 6 Initial Testing of Recommended Flows & Additional Research 7 Watershed Protection Plan 7 Second Flow Workshop & First Hydrology Workgroup Meeting - October 2006 8 Building Blocks for Little and Black Cypress Creeks 8 Further Testing of Recommended Flows & Additional Research 10 Third Flow Workshop & Second Hydrology Workgroup Meeting and Beyond - 10 December 2008 Role of Senate Bill 3 11 Refinement of Building Blocks and Flow Regimes 12 Development of Recommendations for Environmental Flow Standards and Strategies 15 Planning for Future Work 17 Attachments: 19 1. Map of the Cypress River Basin 2. Map of the Caddo Lake Watershed 3. Map of Caddo Lake Watershed Designated as Ramsar Wetlands of International Importance 4. Lists of Major Participating Organizations and Individual Participants 5. Time Table for Major Activities 6. Lake O’ the Pines and the Changes in Flows with Construction of the Dam 7 Key Provisions of Senate Bill 3 8. Dam and Impoundment Statistics for Caddo Lake 9. Lake O’ the Pines Operating Rule Curve
1
SUMMARY
The Cypress Basin Flows Project was initiated in 2004 after the State made the decision that no new water rights would be granted for the purpose of assuring adequate flows in rivers, lakes and bays. Instead, the state leaders proposed and enacted a 2007 law (now “Senate Bill 3”) to provide a process for setting aside water for environmental flows in Texas.
Goal: The Project seeks to assure adequate environmental flows to sustain the ecological, recreational, and economic values of rivers streams and lakes in the Cypress Basin watershed with special emphasis on Caddo Lake and Big Cypress Creek. During the first phase of the Project, there were four major objectives:
1. An SB 3 Flow Reservation or Set Aside: Develop recommendations for SB 3-type “environmental flow standards” for a state reservation of water in the basin based on a consensus of scientists and stakeholders. 2. A New Release Rule for Lake O' the Pines: Develop recommendations for changes in the operations of the dam at Lake O’ the Pines by the Corps of Engineers and NETMWD to provide a more natural pattern of releases, while assuring flood control, water supply, and the other purposes of the reservoir. 3. Flow Needs for Watershed Protection Plan: Serve as the Hydrology Work Group for the state-sponsored Watershed Protection Plan to evaluate and recommend flows, lake level management, etc. to assist with protection of water quality and management of invasive aquatic species. 4. Long-term Adaptive Management: Establish a long-term effort, with the continuation of field work, other research, and consensus decision-making to refine environmental flow recommendations over time.
The Process: Based on a consensus of scientists and stakeholders who attended the orientation meeting in December 2004, the Project has pursued its objectives based on the methodology developed by the National Academy of Sciences for the State of Texas. The Project has relied heavily upon the approach used by the Nature Conservancy-Corps of Engineers’ Sustainable Rivers Program at other rivers in the U.S. and the experience gained in those efforts. The work of the Project has been adjusted with the assistance of the state agencies to be consistent with the goals and intent of both Senate Bills 2 and 3.
Progress to Date: Based on a series of meetings with natural resource experts from Texas and elsewhere and with stakeholders from the Cypress Basin, the Project established an initial set of "building blocks" and SB 3-type “environmental flow regimes.” An adaptive management approach was then initiated, where some of the flows in the building blocks were tested in the field. As a better understanding of the system developed, some of the initial numbers in the building blocks were then changed. In December 2008, a consensus was reached on recommendations for flow regimes, flow standards, and strategies to present to the Texas Commission on Environmental Quality (TCEQ) for a SB 3-type set aside. The participants also set a 3-year review process for the next meetings of the stakeholders and scientists.
The Details: This report is an effort to provide an overview of the work. The details, including the studies used and work summaries, are available at www.caddolakeinstitute.us.
2
A SCIENCE AND STAKEHOLDER-BASED PROCESS
Orientation Meeting and Initial Consensus to Pursue the Project In December 2004, Caddo Lake Institute (CLI) and the Nature Conservancy (TNC) jointly hosted a two-day meeting to discuss the possibilities of a project to develop and pursue sustainable flows regimes for the Cypress Basin. Approximately 80 scientists and stakeholders participated. Facilitated by Brian Richter of the Nature Conservancy, the participants considered the need and options for the work. A consensus was reached that there were or could be found adequate resources for an approach that relied heavily on volunteers working at meetings to develop recommendations based on existing data. With available resources, the testing of the building blocks and other research would also be pursued. It was also agreed that the process would involve scientists and stakeholders meeting together, but that the process would first develop building blocks or flow regimes based on the ecological needs, without consideration of the practical limitations or other needs for the water. Thus, the building blocks would not be constrained by physical or legal limitations or broader goals of stakeholders. Such limitations, interests of stakeholders, and implementation would then be used with the building blocks and flow regimes to develop recommendations for environmental flows, which are called “environmental flow standards” in SB 3. (A summary of SB 3 definitions, goals, and process is provided in Attachment 7.) Summaries of work at the orientation meeting can be reviewed at www.caddolakeinstitute.us/dec04.html. The basic process for developing building blocks is shown in Figure 1. Figure 1. Process for Developing Building Blocks
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Identifying Scientists and Stakeholders One of the first steps, initiated even before the orientation meeting, was identifying scientists and stakeholders. The areas of desired scientific expertise that were identified included: Hydrology and Hydraulics Biology Water Quality Connectivity Fluvial Geomorphology Recruiting the scientists needed for the work was a three step process. The first step was to identify institutions or individuals with a history of working in the watershed. This included people who have studied the ecology of the system and those who had conducted studies related to proposed water development projects. Next, other institutions that were likely to have an interest in this process were identified. This included local, state and federal agencies, university researchers, and private consultants. Finally, the experts identified were then asked to identify others who might be needed or otherwise should be invited to participate. The Cypress Basin has attracted scientific studies for many years. Given that Caddo Lake is Texas’ only naturally-formed large lake, there have been strong interests in the basin. For example, an expert at the National Wetland Resource Center in Lafayette, Louisiana had worked on regeneration of cypress trees in the basin for a number of years. There were also a number of studies associated with the water projects in the basin. These include studies for existing lakes, such as Lake O’ the Pines and Bob Sandlin Lake, and projects that were not completed, such as the proposal for a reservoir on Little Cypress Creek and one for a barge canal across Caddo Lake. A few of these studies included instream flow studies. The studies, and importantly, many of the scientists who participated in them, were available to assist with the Project. Stakeholders were identified in a similar way. The process began with those known to be interested and with the obvious governmental and non-governmental organizations working in the area. That was followed up by requests that stakeholders identify other potential stakeholder-participants. A number of stakeholders not only helped set goals for the process to add practical limits to the flow regimes, they also brought their practical experience and observations to help with the technical evaluations and development of the flow regimes. Anyone was allowed to participate in the meetings, as they were open and all materials prepared for or summarizing the work at the meetings were posted on the website for review and comments. In all, approximately 200 individuals or representatives of organizations participated in one way or another. See Attachment 4 for the list of participants. Literature Review and Summary Report The second major step required significant funding, in the order of $75,000. A team of professors from Texas A&M University was engaged to prepare a report summarizing existing research and studies and synthesizing the results as a basis for environmental flow recommendations. While the report covered most significant studies in the Cypress Basin, the decision was made, for resource and timing reasons, to focus initial work on the Big Cypress Creek between Lake O’ the Pines and Caddo Lake, a 34-mile segment that could be used to test
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some of the proposed flows in the initial building blocks, with experimental releases from the dam at Lake O’ the Pines. The A&M team was headed by Professor Kirk Winemiller and included Professors Anne Chin, Daniel Roelke, Stephen David, Luz Romero, and Bradford Wilcox. Their report, appendices, and annotated bibliography were made available to the participants prior to the first workshop in May of 2005. The documents can be reviewed at www.caddolakeinstitute.us/background.html. Following the first workshop, a supplemental report was prepared by Joe Trungale to help the project focus on other tributaries in the watershed and to provide summaries of studies that were identified after the Texas A&M report, many of which were identified by participants in the first workshop. See www.caddolakeinstitute.us/Docs/2006_CypressHydrology.pdf. Workshops 2005 – 2008 Because of the Nature Conservancy’s experience at other rivers where it had started to work on developing environmental flow proposals, TNC has taken the lead managing the orientation meeting and all workshops to date. Figure 2. The Nature Conservancy-Corps of Engineers Sustainable Rivers Project
The orientation meeting and workshops were multiday events, which included field trips and several days of large meetings and break-out sessions First Flow Workshop – Mary 2005 Attendance at the first workshop included about 90 scientists and stakeholders. The workshop began with a presentation by staff of TNC and covered the goals and objectives of the workshop and expected products as developed in the orientation meeting. This was followed by five presentations by Texas A&M professors, who highlighted key sections of their Summary Report: hydrology (Brad Wilcox), fluvial geomorphology (Anne Chin), nutrients, productivity & aquatic plants (Dan Roelke), riparian and floodplain vegetation (Steve Davis), and aquatic and terrestrial fauna (Kirk Winemiller).
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Following lunch, the workshop participants were divided into two break-out groups for the purpose of developing “building blocks” based on the expected ecological responses or conditions associated with specific river flows or lake level changes. One break-out group focused on Big Cypress Creek, and the other group discussed Caddo Lake. After reporting their findings, the groups were reassembled into two new break-out groups; one focusing on low flows and the other on high-flow pulses and floods. On the second morning, participants discussed data collection and research needs, resulting in a list of priorities for improving their understanding of the role of flows or lake levels on ecological conditions in Big Cypress Creek and Caddo Lake. Following lunch, the Corps of Engineers provided an overview of the operations of Lake O’ the Pines and its role in flood management and water supply. For the full report on the first workshop, together with a list of participants see www.caddolakeinstitute.us/may05.html. Building Blocks for Big Cypress Creek: The building blocks for Big Cypress Creek are presented in Figure 3. Each of the flows portrayed in this figure include an ecological outcome that would be expected if the flow condition is attained. The majority of flows denoted in Figure 3 would have to be generated by water releases from Lake O’ the Pines. As was noted above, the process did not, at that time, try to adjust for limitations, such as flooding, restrictions on operations of the dam, etc. Thus, while the flood flows suggested in Figure 3 cannot be attained unless structural modifications are made to the dam and to downstream levees, these flows were still included in the building blocks. Figure 3. Proposed Building Blocks for Big Cypress Creek, May 2005
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Instream Flow Building BlocksBig Cypress Creek/ Caddo Lake
Low Flows
High FlowPulses
Floods
6,000-10,000 cfs for 2-3 daysEvery 3-5 years
*Maintain aquatic habitat in floodplain* Riparian seed dispersal
* Inhibition of upland vegetation for both creek & lake*Seed dispersal
* Vegetation removal
6,000 cfs for 2-3 days Every 2 years
•For channel maintenance and floodplain connectivity
Key
Dry Year
Avg Year
Wet Year90 cfs
Fish habitat218 – 49 cfs
Spawning habitat13 - 6 cfs
Maintain aquatic diversity40 - 90 cfsFish habitat
268-347 cfsPre-dam median
390 - 79 cfsBenthic drift & dispersal, fish spawning
35 - 40 cfsFish habitat
40 - 117 cfsPre-dam median
40 – 536 cfsMaintain biodiversity and connectivity (backwater & oxbows)
1,500 cfs for 2-3 days3-5X a year every year
* 1 occurring in March for Paddlefish* Sediment transport, oxbow connectivity
•Waterfowl habitat flushing(Includes December)
20,000 cfs for 2-3 daysEvery 10 years
*For channel migration
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The development of building blocks is just one step in the process. Once they are refined, the limits on implementation and the interests of the stakeholders must be considered. That process occurred in 2008 and resulted in recommendations for environmental flow standards for the rivers, streams, and lakes in the basin. During that process, a determination of whether there is sufficient unappropriated water, i.e. water not already locked up in water rights, for the flows was made and, pursuant to the Senate Bill 3 approach, recommendations were developed for strategies to propose how additional water might be made available over time. The low-flow targets in Figure 3 are based upon a variety of ecological objectives. The fish habitat objectives are based upon habitat simulation modeling performed by the U.S. Fish & Wildlife Service. Other targets were based upon the habitat modeling results, as well as a review of the pre-dam low-flow conditions for each month, as derived from the “Indicators of Hydrologic Alteration” (IHA) software. For instance, the 25th percentiles of the pre-dam flows were used as a basis for the July-September flows in dry years, medians were used for setting the October-February average flows, and the 75th percentiles were used as a reference in setting wet year flows. The high-pulse flows in December-June were based upon pre-dam flow records, ecological information provided in the Summary Report, and professional judgment. One of the flood building blocks calls for a flow of 6,000 cfs for the purpose of channel maintenance. This target level is based upon the assumption that the pre-dam, 2-year flood magnitude approximates the bankfull discharge level. A review of the bankfull discharge was, however, identified as a top-priority research need. (Attachment 6 provides a map of the segment under consideration, with pre-dam and post-dam flows.) Building Blocks for Caddo Lake: Caddo Lake received special attention because of its location at the bottom of the Cypress Basin. It also has been designated as a “Wetland on International Importance” under the Ramsar Convention, now signed by 160 nations. See Attachment 3 and www.caddolakeinstitute.us/ramsar.html. One outcome of the first workshop was an initial conclusion that management of flows in Big Cypress Creek may not need to be adjusted to benefit Caddo Lake. This was based largely upon the fact that Big Cypress contributes about one-third of the total inflow to Caddo Lake. The other two-thirds entering Caddo Lake comes from other tributaries that are currently largely unaffected by dams or diversions. These relatively natural inflows from other tributaries result in a considerable rise in lake levels during floods and can provide flows to Caddo sufficient to inundate many of the wetland areas associated with the lake. The dam for Caddo Lake, which is a weir, is fixed with the lowest spillway at an elevation of 168.5 NGVD. (Attachment 8 provides the basic facts on the lake and dam.) Under present conditions, the lake level will drop below that elevation during low flows, but these reduced levels do not often exceed 2 feet. The workshop participants recommended an evaluation of the option of installing an outlet that would allow lowering lake levels for a number of purposes, including nutrient management, cypress regeneration, and invasive species control. (In 2010, the U.S. Army Corps of Engineers announced a plan to begin a study that would include the feasibility of replacing the wier with a dam that includes an outlet for lowering lake levels.)
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The participants also noted that the nutrient levels in Caddo Lake are likely contributing to the undesirable abundance of aquatic plants, phytoplankton blooms, and conditions of low dissolved oxygen. The participants concluded that lake flushing could more efficiently be accomplished by drawing down the lake and that any such nutrient removal effort should be carried out adaptively, using monitoring to inform decisions about the necessary design and duration of the Project. Another potential benefit of lake lowering could be cypress regeneration in areas that presently do not dry sufficiently to allow seed germination and seedling recruitment. Such a drawdown might need to occur in at least two consecutive growing seasons for this goal, which, it was noted, could have significant impacts on use of the lake and the local economy. Figure 4. Proposed Building Blocks for Caddo Lake - May 2005.
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Lake Level Building BlocksCaddo Lake
Low Lake Levels
Normal Lake
Levels
High Lake
Levels
Key
Dry Year
Avg Year
Wet Year
Lake refillingfollowing nutirent and sediment
flushing(requires approx. 15 days?)
Inhibition of upland tree species from encroaching into lake
fringe areas (occurs naturally; requires xx days of
Inundation every xx years)
Lake level lowering fornutrient and sediment flushing
(once every year for up to 10 years)
Lake level lowering forcypress regeneration
(once every 10-20 years, for twoconsecutive growing seasons
Initial Testing of Recommended Flows & Additional Research: Due to dry conditions, the plan to begin testing some of the flow in the building blocks with releases from Lake O’ the Pines was not initially possible. Cypress Basin experienced only low flows in its rivers until the winter of 2007. A number of steps were, however, taken to add to the understanding of the flows in the basin, including: Completion of a museum study of historical fish data. Work on levels of nutrients in sediments and water in the watershed. Characterizing segment and reach-scale channel geomorphologic features. Baseline collections of the fish assemblage. Establishment of instrumented (pressure transducers) cross-sections at non-gauged
locations. Identifying habitat requirements of target organisms.
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Watershed Protection Plan: While the objectives of the Project always included developing building blocks and other recommendations for all major water bodies, not just Big Cypress Creek and Caddo Lake, the offer by TCEQ to sponsor a process to develop a Watershed Protection Plan (WPP) in late 2005 provided a boost to the effort. It also provided an increased opportunity to focus on water quality issues and expand stakeholder outreach. Moreover, with the discovery of Giant Salvinia in Caddo Lake in the summer of 2006 and the recognition of the risks this new invasive aquatic species could bring to the entire watershed, the WPP process provided a better forum for cooperative efforts on management of invasive aquatic plants. It also highlighted the need for cooperation from both sides of the Texas – Louisiana border to protect the entire Cypress Basin. Funding from TCEQ and EPA made it possible for USGS to purchase a new gage for the Big Cypress, downstream of both the dam at Lake O’ the Pines and the existing gage near the dam. City members of the NETMWD and the City of Marshall agreed to fund maintenance of the gage. The work of the WPP has been divided into three workgroups, one specifically focused on the current impairments to water quality in the basin, mainly problems caused by nutrients and bacteria. The second workgroup focuses on invasive species and problems with many septic systems. The third workgroup focuses on hydrology and was combined with the work of this environmental flows Project. Second Flow Workshop & First Hydrology Workgroup Meeting - October 2006 About 80 scientists and stakeholders participated in this three day meeting, which served not only as the second workshop for the flow work, but also the initial meeting of the Hydrology Workgroup for the WPP. The meeting focused on developing the flow regime building blocks for Black and Little Cypress, as well as refining the building blocks for Big Cypress and Caddo Lake. The meeting also provided an opportunity to compare the work of the Project with the State agencies’ plans for implementation of Senate Bill 2, the law that directed the state to prepare detail studies on environmental flows in Texas river basins and bay systems. As a result of the advice from the staff of the State agencies, adjustments in the Project were made to shift some of the research and analysis. Building Blocks for Little and Black Cypress Creek: There was a consensus that the building blocks for Black and Little Cypress could be developed by using the approach taken for Big Cypress Creek. Breakout groups were again relied upon to facilitate discussions. One breakout group proposed that Black Cypress Creek be designated an “untouchable,” essentially setting a narrative flow regime on top of the building blocks that would assure adequate pulse and flood flows for the Big Cypress and to help protect Caddo Lake. The spirit of the recommendation was that there should be no major water projects on Black Cypress. The group felt that Black Cypress Creek should remain in the most pristine state possible to serve as: (1) a source of unregulated flows to Caddo Lake; (2) a reference state for other creeks; and (3) a refuge for biota. (In 2010, The North East Texas Regional Water Planning Group recommended that Black Cypress Creek also be designated an Ecologically Unique Stream Segment.) This breakout group also proposed that historically large flood events should still be allowed to occur on Little Cypress. The group did not, however, recommend that all large floods be
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maintained. Instead it was agreed that some large floods could be captured, provided that the conditions maintained by large floods were within an appropriate range.
There was consensus on the use of the IHA-EFC 25th, 50th and 75th monthly low flow percentile values as reasonable starting values for the low flows recommendations. There was some discussion and agreement for augmenting the IHA-derived monthly percentiles with values developed in a PHABSIM study for Black Cypress. Use of a similar approach was adopted for Little Cypress. The recommended flow from PHABSIM for Black Cypress in September was 75 cfs, while the monthly median flow was 3 cfs. For Little Cypress the breakout group recommended a September flow of 75 cfs with a median flow of 11 cfs. It was recognized that the very low flows, specifically the 25th percentile flows for August-October, might result in a series of disconnected pools. In order to maintain the connectivity between pools, it was proposed that the absolute minimum flows for Little and Black Cypress should not be less than 5 and 4 cfs, respectively. While there was a consensus to follow the Big Cypress approach for the high-flow pulse target at the 2-year flood, there was again considerable discussion about what this flow represents, e.g. whether it reflected the bankfull flow, the effective discharge, or either. Based on the USGS’s preliminary analysis on Big Cypress, it was felt that the 2-year flood may overestimate the physical bankfull flow. Therefore, based on professional judgment, the lower bound on the 95th percentile confidence interval of the 1.5-year flood was selected as a lower range and an upper range, to ensure that the water will get up steep banks in some areas. There was also consensus to develop building blocks for large floods in a manner similar to the approach used as the building block for Big Cypress. For Big Cypress, a building block for a large flood stipulated that a flood of 20,000 cfs (approximately 10-year recurrence interval) should occur once every ten years on average. Thus, for Little and Black Cypress, floods of approximately 13,000 and 8,000 cfs for 2-3 days every ten years were proposed. Figure 5. Proposed Building Blocks for Little Cypress Creek, October 2006
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Figure 6. Proposed Building Blocks for Black Cypress Creek, October 2006
Further Testing of Recommended Flows & Additional Research: With the large rain event in the winter of 2007, the Corps of Engineers and NETMWD were able to provide controlled high flow releases to Big Cypress. USGS had installed a dozen pressure transducers, and, with the assistance of local residents, monitored and retrieved the data from the them. This flow data was then correlated with releases from Lake O’ the Pines as those releases were increased and decreased over several days. The results provided a basis to reconsider pulse and flood flows in the building blocks, as there appear to be significant differences between the segments of Big Cypress upstream and downstream of Jefferson. In addition, a number of other steps were taken prior to the December 2008 flows meeting, including: Cross section surveys on Big Cypress to support HEC-RAS model development by the
Army Corps of Engineers. A meeting on existing studies of aquatic biology in the basin and potential models for
habitat. Modeling for flow-habitat response curves & habitat time series. Measurements to quantify overbank discharge and locations. Flow-inundation mapping.
The work done since the second flows workshop was summarized for presentation at the third workshop. See www.caddolakeinstitute.us/decflowsmeeting08.html. . Third Flow Workshop & Second Hydrology Workgroup Meeting - December 2008 Over 70 scientists and stakeholders participated in this multiday workshop. The workshop began, as the others had, with field trips to Caddo Lake and Big Cypress Creek. Formal meetings were held on the following two days. The objectives of the meeting included:
1. Refinement of the building blocks and environmental flow regimes.
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2. Recommendations for Environmental Flow Standards and Strategies for the basin. 3. A recommendation on the review period, after which the regimes and strategies would be reevaluated. 4. Identification of data gaps and next steps needed to develop recommendations for changes in the operations of the dam at Lake O’ the Pines. 5. The development of a plan for additional research needed to develop recommendations for lake level management options to assist the implementation of the Watershed Protection Plan. 6. Proposing methods to continue the work for adaptive management.
Role of Senate Bill 3: While the work prior to December 2008 had anticipated the passage of a new law in Texas to protect environmental flows, the details of that process were not known until May 2007. The Texas Legislature enacted Senate Bill 3 to create goals and a process for reserving water for environmental flows similar to the process that was being used by this Project. Thus, some time was spent on discussions of Senate Bill 3 and how the Project could work within the framework of Senate Bill 3. Key provisions of that law are shown in Attachment 7. In brief, the law now provides a state policy of protecting environmental flows, a process for developing flow recommendations for each river basin, and a framework for final decisions by the TCEQ for a set aside of unappropriated water in each basin. While the process for the Cypress Basin Project is not exactly the same as that in SB 3, the Cypress Basin work is consistent with the goals and outcomes of SB 3. For example, SB 3 defines “environmental flow regimes” in terms similar to what this Project refers to as “building blocks.”
“Environmental flow regime” means a schedule of flow quantities that reflects seasonal and yearly fluctuations that typically would vary geographically, by specific location in a watershed, and that are shown to be adequate to support a sound ecological environment and to maintain the productivity, extent, and persistence of key aquatic habitats in and along the affected water bodies. Section 11.002, Texas Water Code (TWC).
One difference in the methodologies of SB 3 and the Project result from the decision to use combined meetings for scientists and stakeholder for the Cypress Basin Project, while SB 3 provides for separate meetings. Thus under SB 3, the environmental flow regimes are set by scientists and cannot be changed by the stakeholders, whereas in the Cypress Basin, the regimes were developed in joint meetings with a consensus of both scientists and stakeholders. The Project regimes are science-based and not limited by existing dams, water rights, or future water demands. They did benefit from the input of stakeholders with real world experience and observations on the functioning of the rivers, streams, and lakes. In fact, it is difficult to see how the SB 3 process will not need to provide some of the integration that the Cypress Basin process involves, even if it is only that stakeholders sit in on the discussions of the scientists to understand that process and that some scientists participate in the SB 3 stakeholder discussions to provide information and address questions.
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The process that was developed for the Cypress Basin Flow Project was not revised to fit all of the specifics of the SB 3 process because it appeared that the Project could develop the flow regimes, standards, and strategies called for by SB 3. Both processes focus on the same goals, i.e., a sound scientific basis for the flow recommendations, due consideration of stakeholder’s concerns, and consensus from the process. Moreover, SB 3 anticipates that some basins may develop their only processes and provides:
“...in a river basin and bay system for which the [state environmental flows] advisory group has not yet established a schedule for the development of environmental flow regime recommendations and the adoption of environmental flow standards, an effort to develop information on environmental flow needs and ways in which those needs can be met by a voluntary consensus-building process.” Sec. 11.02362(e), Tex. Water Code.
As discussed below, a significant part of the time at the December 2008 meetings was spent developing a consensus for the environmental flow regimes, standards, and related recommendations. Refinement of Building Blocks and Flow Regimes: The workshop began with a review of the building blocks and environmental flow regimes, followed by development of the recommendations for environmental flow standards and strategies. For both discussions, the process included a series of presentations on the issues, followed by breakout sessions where the participants developed recommendations for the full meeting of the participants. Scientists and stakeholders participated in all of the breakout sessions. A. Review and Revision of the Building Blocks: The initial discussions focused on whether and how the building blocks, which were developed in prior workshops, should be revised based on field work and other technical work completed since the October 2006 workshop. The discussion was divided into two areas of work, 1.) low flows and 2.) pulse and flood flows, as were the breakout sessions that followed.
1. Low Flows: The work done since the flows meeting in October 2006 included an analysis of historic trends in fish assemblages and development of hydrodynamic-habitat models. Existing synoptic surveys suitable to characterize aquatic communities in the river are sparse; however, findings based on the analysis of the available data are consistent with conclusions of pervious research. Thus surveys showed that in Big Cypress Creek below Lake O’ the Pines (LOP), the community has experienced a shift in relative abundances from obligate riverine species such as darters, minnows that broadcast-spawn, and buoyant eggs within current to more habitat generalist species, including Centrarchidae, which spawn elliptical egg envelopes over rock or gravel nests. To evaluate the hypothesis that this shift is related to changes in instream habitat conditions, one-dimensional hydrodynamic models were created based on historical cross section surveys in the Big Cypress. Habitat suitability criteria, developed from site specific collections for dominant species within habitat-spawning guild matrices, were applied to the hydrodynamic model to predict instream habitat conditions as a function of stream flow. Quantities and distributions of available instream habitat types predicted by the models at the building blocks recommended flows were reviewed.
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The following questions were posed to the breakout session on low flows:
Does the change in habitat based on pre vs. post LOP conditions suggest a refinement?
Re-evaluate adjustments from IHA outputs? Refinements for declining guilds? Do we need all three levels (wet/average/dry)? Are the low flows upstream and downstream of Jefferson the same? Does anything jump out as a concern?
In the breakout session that followed, the discussion first focused on if and how this analysis could be used to validate or refine the preliminary flow recommendations. Generally, the analysis showed that the building blocks provide variability in stream habitat conditions. Although the area of some habitat types would be relatively lower than others, this was assumed to be reflective of the natural habitat conditions of the stream, which the recommendations are intended to protect. One clear conclusion from the analysis was that habitat in the lower reach of Big Cypress Creek is less sensitive to changes in flow than in the upper reach. The participants agreed that this type of evaluation is useful in providing insight into what the low flows recommendations would produce in terms of instream habitat, given the lack of any outstanding concerns arising from this analysis, as well as the uncertainty associated with the scarcity of biological data and the hydrodynamic model itself. Yet, the participants then found that the results of this evaluation supported the basic approach taken for low flows in the building blocks for the three rivers and that the results did not suggest any revisions to the approach or prior recommendations for those flows. The breakout group then focused on an issue raised due to low flows for dry conditions in Big Cypress Creek during July through September to assure adequate flows to protect water quality. The state water quality standards and permitting system use a 7Q2 flow of 8.4 cfs1 for this segment of Big Cypress Creek that is higher than the low flow proposed in the building block of 6 cfs. That discussion resulted in a recommendation from the breakout session to revise the building block accordingly and use the 7Q2 flow as a conservative measure until additional data or analysis indicates another value should be used. 2. Pulse and High Flows: Pulse and high flow conditions were then addressed. Field and other work was done by USGS to evaluate these building blocks for Big Cypress Creek. In late 2006, USGS instrumented a number of sites with pressure transducers from just below Lake O’ the Pines to about 2 miles downstream of the confluence of Big Cypress and Black Cypress Creeks to monitor releases from Lake O’ The Pines. Releases from Lake O’ the Pines were monitored over a range of flows from about 50 to 3,000 cfs. Data recorded by the pressure transducers was converted to actual elevations, and low-flow to over-bank flow prescriptions were evaluated for connectivity of hydromorphic unit such as riffles, runs and pools, inundation of woody structure, bankfull height, and over-bank inundation of floodplain wetlands. Based on this work, USGS recommended changes to pulse flows for Big Cypress Creek. In summary, the field work indicated that bankfull flows occurred below 3,000 cfs. The flows needed for bankfull conditions also changed from the upper reach (generally above Jefferson) to
1 7q2 reference: http://info.sos.state.tx.us/fids/30_0307_0010-7.html
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the lower reach (below Jefferson). The high flow pulse for channel maintenance in the building block for Big Cypress Creek could be lowered. The lower flood flows building block was also discussed given that, at 3,000 cfs, there are significant connections to oxbows and other off-channel wetlands. In the breakout session on high flow, a consensus was reached that the building blocks for Big Cypress should be changed. The exact number to be used for high pulses was left to a discussion with the larger group. No recommendation was made for changes to pulse or high flows for Black and Little Cypress Creeks. 3. Recommendations for Building Blocks: The breakout sessions then reported to the full group to seek consensus on the building blocks and the environmental flow regimes. The recommendations from the first breakout session on low flows for Big Cypress Creek to protect water quality were accepted. The discussion then turned to a change to the 6,000 cfs pulse flow for Big Cypress Creek. The discussion led to a consensus for a 2500 cfs flow, which appeared to provide a good approximation of bankfull flow. The lower flood flow was then changed to a range from 3,000 cfs to 10,000 from the prior range of 6,000 to 10,000 to reflect that there was good connectivity accruing at flows as low as 3,000 cfs. Figure 7. Revised Building Blocks for Big Cypress Creek, Dec. 2008
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Instream Flow Building BlocksBig Cypress Creek
Low Flows
High FlowPulses
Floods
20,000 cfs for 2-3 daysEvery 10 years
*For channel migration
2,500 cfs for 2-3 days Every 2 years
* For channel maintenance
Key
Dry Year
Avg Year
Wet YearFish habitat Spawning habitat Maintain aquatic diversity Fish habitat
Pre-dam median Benthic drift & dispersal, fish spawning Fish habitat Pre-dam median
Maintain biodiversity and connectivity (backwater & oxbows)
1,500 cfs for 2-3 days3-5X a year every year
* 1 occurring in March for Paddlefish* Sediment transport, oxbow connectivity
•Waterfowl habitat flushing(Includes December)
396 500 536 445 264 140 70 41 40 49 94 275
268 347 390 330 150 79 35 40 40 40 90 117
90 90 218 198 114 49 13 8.4 8.4 40 90 90
3000 = flow that connectsto oxbows and other off-channelwetlands upstream of Jefferson.
2,500 = about mean bankfull over thereach studied.
2-3 days = peak period for high-flow and floods.
3,000-10,000 cfs for 2-3 daysEvery 3-5 years
*Maintain aquatic habitat in floodplain* Riparian seed dispersal
* Inhibition of upland vegetation for both creek & lake*Seed dispersal
* Vegetation removal
The workshop then focused on the concerns raised in the prior workshop that the pulse and flood flows in Black and Little Cypress Creeks were needed for Caddo Lake and wetland inundation. The confluences of Little and Black Cypress Creek with Big Cypress Creek are just upstream of Caddo Lake and high flows in Black and Little Cypress can provide relatively high flows to the wetlands and lake, even with the reduced flows from Big Cypress due to the existence of Lake O’ the Pines. Thus, the narrative regime approach for pulse and flood flows in Little and Black Cypress discussed in the second workshop were revisited and adopted.
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During these discussions, concern was also raised about the lack of building blocks for James Bayou and a number of small streams in the basin. Because these streams do not have gages, it was agreed that the IHA approach used for Big, Little and Black Cypress Creeks could not be applied. Instead, the group agreed that the flow regimes should be based on the building blocks for Big Cypress Creek with a proportional adjustment for the different sizes of the watersheds. The participants also agreed the building blocks should be evaluated in three years, by which time they should have the additional information from:
1) water quality work for the Watershed Protection Plan, 2) the additional experimental releases from Lake O’ the Pines, and
3) new projections on water needs in the region by the Region D Water Planning Group. Development of Recommendations for Environmental Flow Standards and Strategies: The second area of work proceeded with presentations for developing recommendations for environmental flow standards based on the building blocks, flow regimes, stakeholders’ issues, physical limitations on flows, and other such issues. One key issue was the extent to which there is unappropriated water and/or unused appropriated water available to satisfy the building blocks and flow regimes. TCEQ’s water availability model predicted sufficient water most of the time to meet the flows proposed for Little and Black Cypress Creeks and other parts of the basin, with the exception of Big Cypress Creek. See www.caddolakeinstitute.us/decflowsmeeting08.html. Representatives of the Corps of Engineers and NETMWD also explained the limitations on flows in Big Cypress Creek downstream of Lake O’ the Pines.2 The current design and operations of the dam limit releases to about 3,000 cfs. Existing water rights in Big Cypress, if fully exercised, would also limit the amount of water available for flows downstream of the Lake O’ the Pines dam. Strategies to overcome the deficiencies in the amount of water needed for flows in Big Cypress Creek were then discussed, including the possibility of increasing storage levels in Lake O’ the Pines during certain times of the year and options for purchase, lease, or use of appropriated but unneeded waters. Issues related to the role of flows in protecting water quality and managing invasive aquatic plants were also discussed. Breakout Sessions: The three breakout sessions were:
1. Practical Considerations & Physical Limits on Flows in the Building Blocks; 2. Legal Limitations, Water Rights & Uses, & Future Water Needs for Flows; and 3. Flows & Lake Level Management for Water Quality and Invasive Aquatic Vegetation.
The consensus was that the flows proposed in the building blocks, with the addition of the narrative flow regime for Black and Little Cypress, should be used for the environmental flow 2 The basic information on the Lake O’ the Pines and the Ferrells Bridge Dam can be found in a presentation by the Corps of Engineers at the May 2005 workshop at www.caddolakeinstitute.us/may05.html.
16
standards. In essence, the participants did not believe they had or could obtain in the near future the information they would need to recommend changes to the building blocks for purposes of protection or restoration of water quality or for management of aquatic vegetation. It was noted that the ongoing WPP would provide additional analysis of the water quality impairments in the basin and potential solutions to address those problems. Changes in flows may be one option.
The Corps of Engineers raised a concern that a release of 3,000 cfs might flood downstream oil and gas development and possibly other properties. It asked that this issue be added to the list of research needs for the next workshop. The Corps of Engineers also indicated a desire to expand its computer model for flows in Big Cypress Creek to cover the flows in Little and Black Cypress Creeks at and just above the confluences of these bayous with Big Cypress Creek. Recommendations for Environmental Flow Standards: The following recommendations were developed for the environmental flow standard (EFS), with the proposed language in italics:
1. EFS for Big Cypress Creek: The revised building blocks as limited by the 3,000 cfs maximum flow rate from Lake O’ the Pines and existing water rights. 2. EFS for Black Cypress Creek: A narrative standard: maintain Black Cypress Creek in as natural a condition as possible, allowing additional appropriations of water only where the impacts on the low flow building blocks are de minimis, and where pulses and flood flows are not significantly reduced in timing, duration, or magnitude. 3. EFS for Little Cypress Creek: A hybrid standard: The building blocks, with the exception for flood flows which would include a narrative standard that flood flows should not be further reduced significantly in timing, duration, or magnitude. 4. EFSs for James Bayou and other streams flowing into to Caddo Lake: The building blocks for low and pulse flows for Big Cypress Creek should be used for each stream by adjusting the building blocks in proportion to the size of the watershed of the stream in question to the size of the watershed for Big Cypress Creek. Flood flows should not be reduced significantly in timing, duration, or flow. 5. EFSs for other streams in the Cypress Basin. The building blocks for low, pulse, and flood flows for Big Cypress Creek should be used for each stream by adjusting the building blocks in proportion to the size of the watershed of the stream to the size of the watershed for Big Cypress Creek.
Recommendations for Strategies: The full group then turned its attention to the issues of where there may not be sufficient unappropriated water available to meet the environmental flow standards most of the time. One segment that did not appear to have sufficient unappropriated water was Big Cypress Creek below Lake O’ the Pines. The participants discussed a range of options. They indicated that several strategies should be included in the recommendations for obtaining sufficient water in the future. Those strategies were:
1. Extension of the dates for maintaining the recreational pool from the current period of May 20 to September 30 to the entire year to provide an additional 1.5 feet of storage of
17
water that could be set aside by TCEQ to be released down stream for environmental flows. (See, Attachment 9.) This option would provide much of the needed water downstream of Lake O’ the Pines, but not at all times. 2. Raising the level of storage pool to reallocate some flood storage and provide additional water that could be set aside by TCEQ to be released down stream for environmental flows. 3, Purchase, lease, or otherwise acquiring access to water currently appropriated but not currently used or projected to be needed in the basin.
There was recognition that some strategies, such as raising the level of the storage pool, would require considerable time and effort, including new environmental, cultural, and other studies to evaluate potential impacts.
Planning for Future Work: The participants then turned their attention to the next steps for the Project. Their recommendations can be divided into future work based on the four main objectives described above:
1. An SB 3 Flow Reservation or Set Aside: Develop recommendations for SB 3-type “environmental flow standards” for a state reservation of water in the watershed with associated “strategies” for assuring adequate water based on a consensus of scientists and stakeholders in the basin.
Workshop recommendation: 1.) Develop language for the narrative and hybrid environmental flow standards to circulate to the participants and others for comments. 2.) If a consensus is reached or there is no objection, present these standards, along with the environmental flow regimes and strategies in a summary report to the Texas Environmental Flow Advisory Group, the Texas Environmental Flow Science Advisory Committee, and the Texas Commission on Environmental Quality to seek a set aside pursuant to Senate Bill 3.
2. A New Release Rule for Lake O' the Pines: Develop recommendations for changes in the operations of the dam at Lake O’ the Pines by the Corps of Engineers and NETMWD to provide a more natural pattern of releases, while assuring flood control, water supply, and the other purposes of the reservoir.
Workshop recommendations: 1) Develop additional technical information on flows in Black and Little Cypress Creeks and assist the Corps of Engineers in developing a better HEC RAS model for Big Cypress Creek from Lake O’ the Pines to Caddo Lake. 2) Pursue new field work on potential flooding of developed properties downstream of Lake O’ the Pines at releases up to 3,000 cfs.
18
3) Continue to pursue proposals for changes to the operations of Lake O’ the Pines with the U.S. Corps of Engineers and Northeast Texas Municipal Water District for release of waters from the lake consistent with the building blocks.
3. Flow Needs for Watershed Protection Plan: Serve as the Hydrology Work Group for the state-sponsored Watershed Protection Plan to evaluate and recommend flows, lake level management, etc. and to assist with protection of water quality and management of invasive aquatic species.
Workshop recommendation: Continue to serve as the Hydrology Work Group for the WPP to coordinate the work on water quality and aquatic vegetation with the work on environmental flows.
4. Long-term Adaptive Management: Establish a long-term effort, with the continuation of field work, other research, and consensus decision-making to refine environmental flow recommendations over time.
Workshop recommendation: Continue to pursue field work and other research to gain a better understanding of the ecological needs and values of the Cypress Basin, with a special focus over the next year or two on geomorphology and better indicators of progress at reaching the overall goal of adequate in-stream flows to sustain the ecological, recreational, and economic values of the Caddo Lake watershed and the Cypress Basin.
In addition, the participants proposed that another workshop be scheduled in 3 years to allow the scientists and stakeholders to review the new information and make appropriate revisions to the recommendations from the December 2008 workshop.
19
Attachments
1. Map of the Cypress River Basin in Texas
2. Map of the Caddo Lake Watershed
3. Map of Caddo Lake Watershed Designated as Ramsar Wetlands of International Importance
4. Lists of Major Participating Organizations and Individual Participants
5. Time Table for Major Activities
6. Lake O’ the Pines and the Changes in Flows with Construction of the Dam
7 Key Provisions of Senate Bill 3
8. Dam and impoundment statistics for Caddo Lake
9. Lake O’ the Pines Operating Rule Curve
Attachment 1. Cypress Basin
Attachment 2.
Attachment 4
Major Participating Organizations There have been approximately 200 individual participants. The major organizations that have sent representatives to the multiday workshops are listed below along with the number of representatives from the organization who have participated. Federal Agencies U.S. Army Corps of Engineers (13) U.S. Fish and Wildlife Service (6) U.S. Geological Survey (12) National Wetland Resource Center (3) State Agencies La Depart. of Environmental Quality (2) La Depart. of Wildlife & Fisheries (1) Tx Comm. on Environmental Quality (10) Tx Parks & Wildlife Dept. (12) Tx State Soil & Water Cons. Board (2) Tx Water Development Board (3) Tx Legislature (3) Regional and Local Governments City of Longview (2) City of Marshall (2) City of Uncertain (1) Cypress Valley Navigation District (2) Harrison County (1) North East Tx Municipal Water Dist. (8)
Universities
East Texas Baptist Univ. (1) Louisiana State Univ. Shreveport (1) Middle Tennessee State Univ. (1) Tx A&M Univ. (6) Tx A&M Water Resources Institute (4) Texas Christian Univ. (1) Texas State Univ. (1) Texas Tech Univ. (1) Univ. of Texas – Tyler (2)
Other Organizations American Ecology, Inc. (2) American Electric Power (2) Caddo Lake Area Chamber of Commerce and Tourism (2) Caddo Lake Institute (2) Ducks Unlimited (1) Environmental Defense Fund (1) Espey Consultants (2) Greater Caddo Lake Assn. of Texas (4) HDR Engineering, Inc. (1) National Wildlife Federation (2) Nature Conservancy (6) Nestle Waters North America (1) Red River Valley Association (1) Texas Conservation Alliance (1) TXU/Luminant (1)
Role* Name Area of Expertise Affiliation Ori
en-
tati
o
2005
2006
2008
2006
2007
2008
2009
2010
Total Participants 196 80 90 79 73 68 38 18 10 19
Technical advisor Bird, Mike Biology American Ecology Incorporation x xTechnical advisor Frentress, Carl Biology American Ecology Incorporation x x x
Technical advisor Carter, Greg W
Environmental
Mngmtn. American Electric Power x x x
Technical advisor Meyer, Jennifer K.
Environmental
Mngmtn. American Electric Power x x
Technical advisor Bradbury, Henry Engineering Bradbury Consulting x x x x x
Technical advisor Breeding, Brian Water Quality City of Marshall, Director of Water Supplies x x x
Technical advisor Darville, Roy PhD Water Quality East Texas Baptist University x x x x x x xTechnical advisor Kelly, Mary Law Environmental Defense Fund xTechnical advisor Harkins, David Watershed Mngmnt. Espey Consultants xTechnical advisor Osting, Tim Hydrology Espey Consultants x x x x xTechnical advisor Riebscheager, Kendra Water Quality Espey Consultants xTechnical advisor Guice, W. Lee PhD Engineering Guice Engineering Sciences x xTechnical advisor Price, Paul Water Quality HDR Engineering, Inc. x x xTechnical advisor Boydstun, Jan Water Quality Louisiana Department of Environmental Quality x xTechnical advisor Levy, Linda Water Quality Louisiana Department of Environmental Quality x xTechnical advisor Mouton, Henry Biology Louisiana Department of Wildlife & Fisheries x xTechnical advisor Hanson, Gary PhD Water Quality Lousiana State University - Shreveport x x
Technical advisor Spicer, Gary L.
Environmental
Mngmtn. Luminant/TXU xTechnical advisor Bailey, Frank Biology - Mercury Middle Tennessee State University xTechnical advisor Cordes, Carroll Wetland Science National Wetlands Research Center x xTechnical advisor Keeland, Robert Wetland Science National Wetlands Research Center x x xTechnical advisor Smith, Gregory Wetlands National Wetlands Research Center xTechnical advisor Hess, Myron Law National Wildlife Federation x x x xTechnical advisor Johns, Norman Hydrology National Wildlife Federation x xTechnical advisor Bergan, Jim Biology Nature Conservancy x x x xTechnical advisor Duran, Mike Biology Nature Conservancy xTechnical advisor FitzHugh, Tom Hydrology Nature Conservancy x xTechnical advisor Operman, Jeff Hydrology Nature Conservancy x x x x xTechnical advisor Paterno-Pai, Diedre Hydrology Nature Conservancy x xTechnical advisor Richter, Brian PhD Hydrology Nature Conservancy x x xTechnical advisor Smith, Ryan Hydrology Nature Conservancy x x x x x x xTechnical advisor Warner, Andy Hydrology Nature Conservancy x x xTechnical advisor Wigington, Robert Law Nature Conservancy x xTechnical advisor Blair, Michele Water Quality TCEQ xTechnical advisor Brookins, Linda Water Quality TCEQ xTechnical advisor Chenoweth, Todd Water Rights TCEQ
Technical advisor Cook, Rob Water Quality TCEQ x xTechnical advisor Crowe, Art Water Quality TCEQ x xTechnical advisor Delk, Jennifer Water Quality TCEQ x xTechnical advisor Espino, Frank Water Quality TCEQ xTechnical advisor Gordon, Wendy Hydrology TCEQ x x x xTechnical advisor Rothe, Gail Water Quality TCEQ xTechnical advisor Rubenstein, Carlos Water Rights TCEQ xTechnical advisor Wadick, Ashley Law TCEQ xTechnical advisor Weber, Tom Water Quality TCEQ xTechnical advisor Hansen, Robert Biology TCEQ x xTechnical advisor Fox, Bill Biology Texas A&M Texas Water Resources Institute xTechnical advisor Gregory, Lucas Hydrology Texas A&M Texas Water Resources Institute x xTechnical advisor Harris, BL Water Quality Texas A&M Texas Water Resources Institute xTechnical advisor Jones, C. Allan Water Resources Texas A&M Texas Water Resources Institute x x
Flows
Workshops
Cypress Basin Flows Meetings - Participants 2004-2010
DRAFT August 2010Science Planning
Meetings
Role* Name Area of Expertise Affiliation Ori
en-
tati
o
2005
2006
2008
2006
2007
2008
2009
2010
Flows
Workshops
Cypress Basin Flows Meetings - Participants 2004-2010
DRAFT August 2010Science Planning
Meetings
Technical advisor Chin, Anne Geomorphology Texas A&M University x xTechnical advisor Davis, Stephen Hydrology Texas A&M University x xTechnical advisor Roelke, Dan Hydrology Texas A&M University x x xTechnical advisor Romero, Luz Biology Texas A&M University x xTechnical advisor Wilcox, Brad Hydrology Texas A&M University x x xTechnical advisor Winemiller, Kirk Hydrology Texas A&M University x x xTechnical advisor Duncan, Chris Forestry Texas Forest Service xTechnical advisor Adams, Vanessa Biology Texas Parks & Wildlife Dept. x xTechnical advisor Birdsong, Tim Biology Texas Parks & Wildlife Dept. xTechnical advisor Bister, Tim Biology Texas Parks & Wildlife Dept. x x x xTechnical advisor Brice, Michael Biology Texas Parks & Wildlife Dept. x xTechnical advisor Chilton, Earl Biology Texas Parks & Wildlife Dept. x xTechnical advisor Harriman, Kevin Biology Texas Parks & Wildlife Dept. x xTechnical advisor Kokkanti, Praveen Biology Texas Parks & Wildlife Dept. xTechnical advisor Mason, Corey Biology Texas Parks & Wildlife Dept. x xTechnical advisor Maxey, Ricky Biology Texas Parks & Wildlife Dept. xTechnical advisor Mayes, Kevin Hydrology Texas Parks & Wildlife Dept. x x x x x x xTechnical advisor Mosier, Doyle Biology Texas Parks & Wildlife Dept. x xTechnical advisor Moss, Randy Biology Texas Parks & Wildlife Dept. x xTechnical advisor Ryan, Mike Biology Texas Parks & Wildlife Dept. x x xTechnical advisor Shen, Yi Biology Texas Parks & Wildlife Dept. xTechnical advisor Whisenant, Adam Biology Texas Parks & Wildlife Dept. x x x x xTechnical advisor Berry, Max Water Quality Texas State Soil & Water Conservation Board x xTechnical advisor Wendt, Aaron Water Quality Texas State Soil & Water Conservation Board xTechnical advisor Bonner, Tim Biology Texas State University xTechnical advisor Perkins, Joshuah Biology Texas State University xTechnical advisor Rainwater, Thomas Biology Texas Tech University x x xTechnical advisor Furnans, Jordan Hydrology Texas Water Development Board xTechnical advisor Raphelt, Nolan Hydrology Texas Water Development Board x xTechnical advisor Wentzel, Mark Hydrology Texas Water Development Board x xTechnical advisor Chumchal, Matthew Biology - Mercury Texas Christian University x x xTechnical advisor Trungale, Joe Hydrology Trungale Engineering x x x x x x x x xTechnical advisor Ford, Neil Biology University of Texas - Tyler x xTechnical advisor Bransford, Mike Hydrology US Army Corps of Engineers x xTechnical advisor Griffith, Becky Hydrology US Army Corps of Engineers x x xTechnical advisor Hackett, Marcia Hydrology US Army Corps of Engineers x xTechnical advisor Hedges, Raymon Engineering US Army Corps of Engineers x xTechnical advisor Jones, Tommy Engineering US Army Corps of Engineers x xTechnical advisor Kelly, Charissa Hydrology US Army Corps of Engineers x x x x xTechnical advisor King, Wendell Engineering US Army Corps of Engineers x xTechnical advisor Lauderdale, Paul Hydrology US Army Corps of Engineers x x x x xTechnical advisor Loftin, Craig Hydrology US Army Corps of Engineers x xTechnical advisor Newman, Rob Hydrology US Army Corps of Engineers xTechnical advisor Rodman, Paul Hydrology US Army Corps of Engineers x x x x x x xTechnical advisor Shirley, Edward Hydrology US Army Corps of Engineers xTechnical advisor Stockstill, Wayne Hydrology US Army Corps of Engineers x xTechnical advisor Thrift, Michelle Watershed Mngmnt. US Army Corps of Engineers xTechnical advisor Underwood, Martin Watershed Mngmnt. US Army Corps of Engineers xTechnical advisor Vanderpool, Marie Hydrology US Army Corps of Engineers x xTechnical advisor Wilson, David Hydrology US Army Corps of Engineers x x x xTechnical advisor Owens, Chetta Hydrology US Army Corps of Engineers (LAERF) xTechnical advisor Killgore, Jack Biology US Army Corps of Engineers (WES) x xTechnical advisor Echols, William T. Engineering US Army Corps of Engineers, Retired x x x xTechnical advisor Anderson, Robert Biology US Fish & Wildlife Service x
Role* Name Area of Expertise Affiliation Ori
en-
tati
o
2005
2006
2008
2006
2007
2008
2009
2010
Flows
Workshops
Cypress Basin Flows Meetings - Participants 2004-2010
DRAFT August 2010Science Planning
Meetings
Technical advisor Broska, James Biology US Fish & Wildlife Service x x xTechnical advisor Bruckwicki, Paul Biology US Fish & Wildlife Service x x x xTechnical advisor Cloud, Tom Biology US Fish & Wildlife Service x x x x xTechnical advisor Lewis, Jacob Biology US Fish & Wildlife Service x xTechnical advisor Neal, Jim Biology US Fish & Wildlife Service x x x xTechnical advisor Becher, Kent Hydrology US Geological Survey x xTechnical advisor Brown, David Hydrology US Geological Survey x xTechnical advisor East, Jeffrey Hydrology US Geological Survey x xTechnical advisor Heitmuller, Franklin Hydrology US Geological Survey x x xTechnical advisor Johnston, James Hydrology US Geological Survey xTechnical advisor Joseph, Robert (Bob) Hydrology US Geological Survey xTechnical advisor Konrad, Chris Hydrology US Geological Survey xTechnical advisor Mabe, Jeffrey Hydrology US Geological Survey xTechnical advisor Moring, Bruce Hydrology US Geological Survey x x x x x x x x xTechnical advisor Raines, Tim Hydrology US Geological Survey
Technical advisor Rosendale, John Hydrology US Geological Survey xTechnical advisor Wilson, Jennifer Hydrology US Geological Survey x x xTechnical advisor Njue, Obadiah PhD Biology Wiley College x xTechnical advisor Plata, Ernest PhD Biology Wiley College x xStakeholder Coleman, Terry Caddo Lake Area Chamber of Commerce xStakeholder Webb, Jay & Patty Caddo Lake Area Chamber of Commerce x x xStakeholder Werneke, Jean Caddo Lake Area Chamber of Commerce x xStakeholder Shellman, Dwight JD Caddo Lake Insititute x x xStakeholder Haverlah, Sandra Caddo Lake Institute xStakeholder Lowerre, Richard Caddo Lake Institute x x x x x x x x xStakeholder Stephens, V.A. Caddo Lake Institute x x xStakeholder Bonds, Keith City of Longview xStakeholder House, Ben City of Longview xStakeholder Powers, William "Buddy" City of Marshall, Chairman of City Commission xStakeholder Rasor, Anthony City of Mt. Pleasant xStakeholder Canup, Sam & Randi City of Uncertain, Mayor x x x xStakeholder Sanders, Bob Cypress River Ranch xStakeholder Shaw, Ken Cypress Valley Navigation District, Board Chairman x x x x xStakeholder Walker, Tom Cypress Valley Navigation District, Board Member x x x xStakeholder McKnight, Keith Ducks Unlimited xStakeholder Canson, Jack Greater Caddo Lake Assn. x x x x xStakeholder Munden, Ron Greater Caddo Lake Assn. x xStakeholder Speight, Robert Greater Caddo Lake Assn. x x x x x x
Stakeholder Parker, Doug Greater Caddo Lake Assn., President x x xStakeholder Anderson, Richard Harrison County, County Judge x xStakeholder Alexander, Corby Jeffersonian Institute x xStakeholder DeWare, Jesse, 3rd, LLB Jeffersonian Institute x x xStakeholder Endsley, Gary Jeffersonian Institute x x x x xStakeholder Haden, Bryon Jeffersonian Institute x xStakeholder Harrell, Carol Ed.D Jeffersonian Institute x x xStakeholder Keasler, Mary Jeffersonian Institute x xStakeholder Weber, Dan Nature Conservancy, Louisiana x x x x xStakeholder Bartlett, Richard Nature Conservancy, Texas
Stakeholder Bezanson, David Nature Conservancy, Texas x x xStakeholder Bristol, Valarie Nature Conservancy, Texas x x xStakeholder Feckley, Dave Nestle Waters North America xStakeholder Allen, Beverly Northeast Texas Municipal Water District x xStakeholder Blevins, Ric Northeast Texas Municipal Water District x
Role* Name Area of Expertise Affiliation Ori
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tati
o
2005
2006
2008
2006
2007
2008
2009
2010
Flows
Workshops
Cypress Basin Flows Meetings - Participants 2004-2010
DRAFT August 2010Science Planning
Meetings
Stakeholder Muse, Marty Northeast Texas Municipal Water District xStakeholder Pafford, Howard Northeast Texas Municipal Water District x xStakeholder Thomas, Lee Northeast Texas Municipal Water District x xStakeholder Brown, William Northeast Texas Municipal Water District, Board Member x x x xStakeholder Salmon, Jack Northeast Texas Municipal Water District, Board Member x xStakeholder Sears, Walt Northeast Texas Municipal Water District, General Manager x x x x x x x xStakeholder Brontoli, Richard Red River Valley Association x xStakeholder LeTourneau, Richard Region D Water Planning Group (TX) x x x xStakeholder Johnson, Judith Resident x xStakeholder Turner, Michael Resident x xStakeholder Weaver, Pamela Resident x xStakeholder Cullum, Brandon Resident x xStakeholder Hamblin, Russell Resident x xStakeholder Barrow, Ted Resident, City of Jefferson xStakeholder Cary, Richard Resident, City of Jefferson x xStakeholder DePrez, Francene Resident, City of Jefferson xStakeholder Lang, Frank Resident, City of Jefferson xStakeholder Pate, Eddie Resident, City of Jefferson xStakeholder Weber, Michael Resident, City of Jefferson xStakeholder Bailey, Phyllis Resident, City of Marshall x xStakeholder Byassee, Peggy Resident, City of Marshall x xStakeholder Dixon, Charles Resident, City of Marshall xStakeholder Fitch, Kyle Resident, City of Marshall x xStakeholder Gordon, John Resident, City of Marshall x xStakeholder Harris, Jim Resident, City of Marshall xStakeholder McMurry, Mike Resident, City of Marshall x xStakeholder Purvis, Marcia Resident, City of Marshall x xStakeholder Sanders, Jack Resident, City of Marshall x x xStakeholder Sanders, MaryJane Resident, City of Marshall x xStakeholder Gray, Vickie Resident, Jonesboro, LA xStakeholder Fortune, Paul Resident, Karnack x x x xStakeholder Fyffe, Mike Resident, Karnack x xStakeholder Parsons, David Sabine River Authority (TX) x xStakeholder Stripling, Kelly Senator Todd Staples' Office x xStakeholder Broad, Tyson Sierra Club
Stakeholder McReynolds, Allen Sierra Club
Stakeholder Martin, Marie State Rep. Stephen Frost's Office x xStakeholder Flynn, Dan State Representative xStakeholder Collins, Chris TCEQ x
Stakeholder Biggers, Leroy TCEQ, Tyler Regional Office, Director x x x xStakeholder Bezanson, Janice Texas Conservation Alliance xStakeholder Bonds, Craig Texas Parks & Wildlife Dept., Regional Director x xStakeholder Dickinson, Todd Texas Parks & Wildlife Dept., Caddo Lake State Park xStakeholder Farmer, Dee State Senator Kevin Eltife's Office xStakeholder Williams, Mark US Fish & Wildlife Service, Caddo Lake Refuge Mgr. x x x x x
*The designation of who is a techical advisor and who is a stakeholder was sometimes very arbitrary. Many of those listed as stakeholders brought valuable
expertise to the process, and some of those listed as technical advisors may have seen their role more as a stakeholder. We apologize if we have
mischaracterized anyone's role.
Attachment 5 Time Table for Major Activities
December 2004: Orientation Meeting. (~60 Scientists and Stakeholders) April 2005: Texas A&M Summary Report - on Past Scientific Studies. May 2005: First Project Workshop. (~90 Scientists and Stakeholders) Fall 2005 – Fall 2008: Research & Filling Data Gaps: Field Work and Other Research. April & May 2006: Science Planning Meetings – Two (at Caddo and Austin) to Guide
Research. September 2006: Hydrology Update. Expansion & Update of Texas A&M Summary Report. October 2006: Historic Trends in Fish Community, Cypress Basin. Texas State University. October 2006: Second Project Workshop. (~80 Scientists and Stakeholders) Also Served as
the First Hydrology Workgroup Meeting for the Parallel State Sponsored Caddo Lake Watershed Protection Planning Process.
May & June 2007: Science Planning Meetings – Two (at Caddo and Austin) to Guide
Research. July 2008: Science Planning Meeting – In Austin to Guide Research. December 2008: Third Project Workshop. (~ 75 Scientist and Stakeholders) Also Served as
the Second Hydrology Workgroup Meeting for the Parallel State Sponsored Caddo Lake Watershed Protection Planning Process.
January 2009: Science Planning Meeting – In Austin to Guide Research for Fourth Project
Workshop and Adaptive Management. January & May 2010: Science Planning Meetings – In Austin to Guide Research on
Indicators of Success and for Fourth Project Workshop and Adaptive Management. Fall 2011: Proposed date for Fourth Project Workshop.
Attachment 6: Lake O’ the Pines and the Changes in Flows with Construction of the Dam
The range of flows changed significantly with the construction of the dam. Before the dam was built in 1959, flow in Big Cypress Creek above Caddo Lake ranged as high as 57,000 cfs. The maximum release now from the dam to Big Cypress is 3000 cfs. Thus, the variation of flows and the inundation of wetlands along Big Cypress and in Caddo Lake are limited by the construction of the dam. Current law requires only a 5 cfs release from the dam, although NETMWD has generally provided greater releases. There was no gaged information for 1960 to 1980.
Daily Average Streamflow in Big Cypress Creek at USGS Gage 07346000
0
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Dis
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e (cfs
)
Attachment 7 KEY PROVISIONS OF SB 3 Definitions (15) Environmental flow analysis means the application of a scientifically derived process for predicting the response of an ecosystem to changes in instream flows or freshwater inflows. (16) Environmental flow regime means a schedule of flow quantities that reflects seasonal and yearly fluctuations that typically would vary geographically, by specific location in a watershed, and that are shown to be adequate to support a sound ecological environment and to maintain the productivity, extent, and persistence of key aquatic habitats in and along the affected water bodies. (17) Environmental flow standards must consist of a schedule of flow quantities, reflecting seasonal and yearly fluctuations that may vary geographically by specific location…. Goals: The [TCEQ] by rule shall:
1) adopt appropriate environmental flow standards for each river basin … that are adequate to support a sound ecological environment, to the maximum extent reasonable considering other public interests and other relevant factors; (2) establish an amount of unappropriated water, if available, to be set aside to satisfy the environmental flow standards to the maximum extent reasonable when considering human water needs….
An environmental flow set-aside... must be assigned a priority date corresponding to the date the [TCEQ] receives environmental flow regime recommendations … and be included in the appropriate water availability models in connection with an application for a permit for a new appropriation... Methodology: Each … expert science team shall develop environmental flow analyses and a recommended environmental flow regime for the river basin … through a collaborative process designed to achieve a consensus. In developing the analyses and recommendations, the science team must consider all reasonably available science, without regard to the need for the water for other uses… Each … stakeholders committee shall review the environmental flow analyses and environmental flow regime recommendations submitted by the … expert science team and shall consider them in conjunction with other factors, including the present and future needs for water for other uses … The … stakeholders committee and the advisory group may not change the environmental flow analyses or environmental flow regime recommendations of the … expert science team. The … stakeholders committee shall develop recommendations regarding environmental flow standards and strategies to meet the environmental flow standards and submit those recommendations to [TCEQ.] ...in a river basin and bay system for which the [state environmental flows] advisory group has not yet established a schedule for the development of environmental flow regime recommendations and the adoption of environmental flow standards, an effort to develop information on environmental flow needs and ways in which those needs can be met by a voluntary consensus-building process (as this Project is doing for the Cypress watershed).
Attachment 8
DAM AND IMPOUNDMENT STATISTICS FOR CADDO LAKE*
– LOCATION – On Cypress Bayou in Caddo Parish, Louisiana 19 Miles Northwest of Shreveport, Louisiana. The Lake Extends into Harrison and Marion Counties, Texas.
– DRAINAGE AREA – 2,700 Square Miles (Includes Drainage Area of Lake O’ The Pines).
– DAM –
Type ........................................................................................................... Earthfill and Concrete Spillway Maximum Height .................................................................................................................. 36 Ft. Top Width ..............................................................................................................................30 Ft.
– SPILLWAY – Type.................................................................................................... Floodwall (Broad-Crested Wier) Control ................................................................................................................................ None.
– AUTHORIZATION – Federal ............................................................................................. Flood Control Act of October 27, 1965
– RESERVOIR DATA –
(Data From U. S. Army Corps of Engineers, New Orleans District)
Feature Feet Above M.S.L.
Acre Feet Acres
Top of Dam 176.0 391,400 43,000
Spillway High Section 170.5 186,600 31,000
Spillway Low Section 168.5 129,000 26,800
Dead Storage 168.0 69,200 20,700
Usable Storage – 59,800 –
– GENERAL –
Construction Started .......................................................................................................... August 7, 1968 Dam Completed .................................................................................................................. June 18, 1971 Impoundment of Water Began ............................................................................................1914 __________________ *Source: Caddo Lake Contoured Depth Topo Map, A.I.D., Associates, Inc./Publishers, 1993
Attachment 9
DRAFT
Appendix B 1
APPENDIX B DATA COLLECTION AND RESEARCH NEEDS {This list of research priorities was originally developed at the firs flows workshop in May 2005 and has been
updated subsequently as new priorities have arisen. These items have been reorganized according to the
categories fitting with the State Instream Flows Program and our most current process. Items in bold are in‐
progress or completed.}
River System
Hydrology and Hydraulics:
Develop correlation between old and new Jefferson flow gauging sites, or re‐establish gage.
What was the pre‐dam (LOP) duration of small floods?
How much gain/loss (ground water, ET, and diversions) of water between LOP and Caddo Lake?
Establish new USGS gage 07346080 Big Cypress Creek above SH 43 near Karnack, TX.
Establish instrumented cross‐sections at non‐gaged locations for continuous monitoring of stage, temperature, and discharge.
Evaluate limitations of flow in Big Cypress downstream of LOP to determine maximum flood flow augmentation possible from LOP.
Evaluate historic USACE models and reports, identify historic high water marks (tree pegs.)
Water flow patterns associated with inflows in upper lake areas.
Biology:
Paddlefish and bluehead shiner ecology (including, is enough spawning area left in Big Cypress Creek to support viable populations of each?)
Conduct baseline, reach‐based biological assessments of benthic macro‐invertebrate assemblages and riparian vegetation.
Comparison of floodplain vegetation communities in Big Cypress with other tributaries.
Historical analysis of vegetation change (including use of GLO survey data.)
Assessment of instream habitat availability at different low‐flow levels.
Survey of non‐game fishes (including 14 spp. of fish not documented recently) and benthic invertebrates (especially mussels) throughout basin.
Conduct baseline, reach‐based and synoptic biological status assessments of fish assemblages.
Analysis of historical trends in Cypress Basin fish assemblages.
Monitoring Cypress regeneration.
Water Quality:
Clean Rivers Program and TCEQ continuous monitoring.
Nutrient balance.
Monitoring of contamination of fish and wildlife.
Flow needed in tributaries to flush sediment and contaminants from upper end of Lake.
Geomorphology:
Estimate sediment budget and develop better characterization of sediment composition along entire creek.
Collect baseline geomorphological data to assess the responses during and following flow releases (include sediment characteristics, channel cross section and general assessment of channel condition.)
DRAFT
Appendix B 2
Connectivity:
Assess floodwater accumulation (flood magnitude‐frequency relationships) and backwater hydraulics below confluence of Little Cypress and Black Cypress.
How much of floodplain is inundated and how much fish access is available at various flow levels (>2000 cfs?) in various reaches of the creek? (including bankfull discharge level)
Flood inundation‐vegetation relationships.
Floodplain mapping and tie to geomorphic features and development.
Flood release options for LOP: Baseline, reach‐based biological assessments of riparian vegetation in association with monumented reaches and cross‐sections.
Duration of off‐channel connectivity and persistence of water in floodplain required for aquatic organisms.
Implementation Concerns:
Public participation in flow restoration program and input to goal‐setting for adaptive management.
Articulation of expected ecological and ecosystem service benefits associated with flow restoration (for communication with stakeholders and water managers.)
Potential flood impacts on communities downstream of Lake o’ the Pines.
Impacts of human developments on flooding and water quality (including impediments to flood implementation.)
Implications of flow restoration on other water uses and needs (including Lake o’ the Pines.)
Improvements in ability to forecast climate and water availability.
Caddo Lake System
Hydrology and Hydraulics:
Summation of cumulative inflows (daily) into Caddo Lake and assessment of relative impact of Lake o’ the Pines on these cumulative inflows.
Lake level variation associated with inflow variation (and relationship to water diversions or intakes.)
Flow needed in tributaries to flush sediment from upper end of lake.
Water flow patterns associated with inflows in upper lake areas.
Evaluate outlet controls for dam on Caddo Lake.
Lake conditions, bottom profiles, shoreline positions and upland exposures with different inflows.
Biology:
Amphibian and mammal data gaps throughout basin.
Avian faunal (including waterfowl) data gaps throughout basin.
Lake fringe (area) exposed at different lake levels (for cypress regeneration.)
Targeted relative abundance or area for different bottomland‐hardwood communities.
Evaluate control strategies for invasive aquatic species
Lake levels (and duration) needed for cypress regeneration.
Water Quality:
Conduct nutrient and sediment budgets for Caddo lake.
Aquatic vegetation control and nutrient reduction.
How much flow is needed in Big Cypress to flush nutrients and pollutants in lake when other tributaries are simultaneously contributing water?
DRAFT
Appendix B 3
Control strategies for invasive shrubs and other plants that could invade during lake drawdowns (e.g., hydrilla, Chinese tallow, buttonbush, water elm.)
How do we use lake level to knock back hydrilla without losing diversity of other plant species?
Phytoplankton: what’s here, conduct survey in late summer.
Investigate results of drawdowns in other lakes to control hydrilla and nutrients. Time required to refill lake after drawdowns.
Extent (depth) of drawdown necessary to gain desired nutrient reduction effect.
Rate of drawdown needs to be evaluated.
Geomorphology:
Bathymetry of lake (and relationship to drawdowns.)
Connectivity:
Lake levels (and duration) needed to knock back bottomland hardwood tree species around lake fringe.
Flows needed to inundate wetlands.
Implementation concerns:
Effects of lake drawdown on sport fishery and economy of Caddo Lake area.
Public participation in flow restoration program and input to goal‐setting for adaptive management.
Articulation of expected ecological and ecosystem service benefits associated with flow restoration (for communication with stakeholders and water managers.)
Potential flood impacts on communities around and downstream of Caddo Lake.
Impacts of human developments on flooding and water quality (including impediments to flood implementation.)
DRAFT
Appendix C 1
APPENDIX C HABITAT MODELING {The figures on the following pages were distributed to the Cypress Flow Project workgroup at the third flows
workshop in December 2008.}
EFC Monthly Low Flows
TAMU Summary Report07346000 Big Cypress Ck nr Jefferson_IHA_TAMU_2005
25% 50% 75%January 116 268 396February 195 347 500March 218 389 536April 198 333 444May 114 150 264June 49 81 140July 13 39 70August 6 12 41September 6 12 32October 6 26 49November 26 56 94December 61 117 275
Workshop RefinementsJanuary 90 268 396February 90 347 500March 218 390 536April 198 330 445May 114 150 264June 49 79 140July 13 35 70August 6 40 41September 6 40 40October 40 40 49November 90 90 94December 90 117 275
Appendix C 2
0
50
100
150
200
250
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Post_DryPre-Dry
Appendix C 3
Table 6-1
Habitat guilds for Cypress and Twelvemile Bayou fishes, based on preferredvelocities (horizontal axis! and spawning substrate (vertical axis). Evaluation species for reservoirs (*) and streams (**) are indicated.
LACUSTRINE/GENERALISTS SLACK WATER SWIFT WATER
0PEN
SAND
AND
GRAVELS
VEGETATI0N
CREVICE
Gizzard shadMosqultoflsh
Red shinerGreen sunfishOrangespottedBluegill
*
sunfish
Redear sunfishLsrgemouth bass White Crappie **Black crappie
Bowfin *Common carpGolden shinerBrook silverside **
**
Bullhead minnowBlack bullheadYellow bullhead **Channel catfish
American eelThreadfin shadCypress minnowSilvery minnowRibbon shiner
Skipjack herringEmerald shinerMimic shinerFreshwater drum
Redfin shinerPallid shinerBluehead shinerPugnose minnow **River carpsuckerCreek chubsuckerSpotted suckerBlacktail redhorseGolden topminnowFlierWarmouthRedbreast sunfishDollar sunfishLongear sunfish **Spotted sunfishBantam sunfishSpotted bassMud darter
Chestnut lampreyBlackspot shinerStriped shinerIroncolor shinerSand shinerWeed shinerYellow bassWhite BassScaly sand darterHarlequin darterGoldatripe darterRedfin darterRiver darterBlackside darterDusky darter
Spotted garShortnose garAlligator garGrass pickerelChain pickerelTaillight shinerLake chubsuckerSmallmouth buffaloBigmouth buffaloStarhead topminnowBlackstripe topminnow
Longnose garBlack buffalo
Blackspotted topminnowInland silversideBanded pygmy sunfishBluntnose darterSwamp darterSlough darter
Blue catfishTadpole madtomFlathead catfishPirate perchCypress darter
** Blacktail shiner
6-2
Appendix C 4
53BG 59BG 92BG 92BG 92BG 92BG 98BG 99BG 99BG 06BG 06BG 06BG 06BG 07BGBig Cypress 53 59 92 92 92 92 98 99 99 06 06 06 06 07Order Guild BG001 BG002 BG003 BG004 BG005 BG006 BG007 BG008 BG009 BG010 BG011 BG012 BG013 BG014 Slope Rank
6 Slack Water-Sand and Gravel Spotted Sucker, Spotted Bass 8 27 2 8 5 2 14 54 78 34 38 30 27 39 124 12 Lacustrine/Generalist-Sand and Gravel Largemouth Bass, White & Black Crappie (USFWS) 4 11 0 0 0 0 0 0 0 18 12 23 29 12 51 37 Slack Water-Vegitation Pickerel, Bluntnose Darter 6 1 79 9 0 3 66 46 3 18 9 6 4 6 51 28 Slack Water-Cervice Flathead Catfish 0 0 0 5 0 0 2 0 7 0 2 0 1 2 9 44 Lacustrine/Generalist-Cervice Channel Catfish (USFWS) 0 0 0 0 0 0 0 0 0 2 2 1 4 0 9 5
12 Swift Water-Cervice Blacktail Shinner 19 1 0 3 0 14 0 0 0 4 6 10 15 31 2 71 Lacustrine/Generalist-Open Gizzard Shad (USFWS) 2 6 0 0 0 0 0 0 0 3 6 4 3 4 -4 93 Lacustrine/Generalist-Vegitation Brook Silverside (WES84) 8 7 0 0 2 0 0 0 12 13 12 8 7 2 2 8
11 Swift Water-Vegitation None 0 0 0 0 0 2 9 0 0 0 1 0 0 1 4 69 Swift Water-Open Freshwater Drum (USFWS) 3 0 0 0 0 0 0 0 0 0 1 0 1 0 -5 105 Slack Water-Open None 7 1 2 4 2 21 0 0 0 3 1 0 0 0 -23 11
10 Swift Water-Sand and Gravel Iron Color Shinner, Blackside Darter 43 46 17 71 91 59 10 0 0 5 11 18 7 2 -221 12
Big Cypress
0
5
10
15
20
25
30
35
40
45
50
1950
1960
1970
1980
1990
2000
Date
Rel
ativ
e A
bund
ance
Slack Water-Sand and Gravel
Lacustrine/Generalist-Sand and Gravel
Slack Water-Vegitation
Slack Water-Cervice
Lacustrine/Generalist-Cervice
Swift Water-Cervice
Lacustrine/Generalist-Open
Lacustrine/Generalist-Vegitation
Swift Water-Vegitation
Swift Water-Open
Slack Water-Open
Swift Water-Sand and Gravel
Linear (Slack Water-Sand and Gravel)
Linear (Lacustrine/Generalist-Sand and Gravel)
Linear (Slack Water-Vegitation)
Linear (Slack Water-Cervice)
Linear (Lacustrine/Generalist-Cervice)
Linear (Swift Water-Cervice)
Linear (Lacustrine/Generalist-Open)
Linear (Lacustrine/Generalist-Vegitation)
Linear (Swift Water-Vegitation)
Linear (Swift Water-Open)
Linear (Slack Water-Open)
Linear (Swift Water-Sand and Gravel)
0%
20%
40%
60%
80%
100%
53B
G
59B
G
92B
G
92B
G
92B
G
92B
G
98B
G
99B
G
99B
G
06B
G
06B
G
06B
G
06B
G
07B
G
Swift Water-Sand and Gravel
Slack Water-Open
Swift Water-Open
Swift Water-Vegitation
Lacustrine/Generalist-Vegitation
Lacustrine/Generalist-Open
Swift Water-Cervice
Lacustrine/Generalist-Cervice
Slack Water-Cervice
Slack Water-Vegitation
Lacustrine/Generalist-Sand and Gravel
Slack Water-Sand and Gravel
Appendix C 5
53BG 59BG 92BG 92BG 92BG 92BG 98BG 99BG 99BG 06BG 06BG 06BG 06BG 07BGs 53 59 92 92 92 92 98 99 99 06 06 06 06 07Guild BG001 BG002 BG003 BG004 BG005 BG006 BG007 BG008 BG009 BG010 BG011 BG012 BG013 BG014 Slope Rank MaxLepomis megalotis Slack Water-Sand and Gravel 0 3 0 0 0 0 0 0 0 16 18 17 17 10 68 1 18Lepomis macrochirus Lacustrine/Generalist-Sand and Gravel 1 2 0 0 0 0 0 0 0 13 9 14 18 3 46 2 18Lepomis miniatus Slack Water-Sand and Gravel 1 2 0 0 0 0 0 0 1 14 16 6 1 10 37 3 16Fundulus notatus Slack Water-Vegitation 4 1 60 0 0 0 66 4 0 13 5 5 1 5 33 4 66Centrarchus macropterus Slack Water-Sand and Gravel 1 0 0 0 0 0 0 0 64 0 0 0 0 6 28 5 64Fundulus chrysotus Slack Water-Sand and Gravel 0 0 0 0 0 0 7 42 3 1 1 2 0 2 25 6 42Labidesthes sicculus Lacustrine/Generalist-Vegitation 7 1 0 0 0 0 0 0 12 10 11 8 4 2 14 7 12Fundulus dispar Slack Water-Vegitation 0 0 0 0 0 0 0 33 0 0 0 0 0 0 13 8 33Lepomis microlophus Lacustrine/Generalist-Sand and Gravel 1 0 0 0 0 0 0 0 0 3 2 6 4 0 13 9 6Lepomis marginatus Slack Water-Sand and Gravel 0 0 0 0 0 0 0 0 0 0 0 0 0 11 11 10 11Micropterus punctulatus Swift Water-Sand and Gravel 1 2 0 0 0 0 0 0 0 4 8 3 4 1 10 11 8Ictalurus punctatus Lacustrine/Generalist-Cervice 0 0 0 0 0 0 0 0 0 2 2 1 4 0 8 12 4Lepisosteus oculatus Slack Water-Vegitation 0 0 0 0 0 0 0 0 0 4 2 0 1 0 7 13 4Lepomis symmetricus Slack Water-Sand and Gravel 0 0 0 0 0 0 0 13 5 0 0 0 0 0 7 14 13Pomoxis nigromaculatus Lacustrine/Generalist-Sand and Gravel 1 0 0 0 0 0 0 0 0 0 0 0 0 8 7 15 8Cyprinus carpio Lacustrine/Generalist-Vegitation 0 0 0 0 0 0 0 0 0 3 1 0 2 0 6 16 3Lepomis gulosus Slack Water-Sand and Gravel 0 0 0 0 0 0 0 0 0 1 2 2 2 0 5 17 2Percina sciera Swift Water-Sand and Gravel 0 0 2 2 0 0 0 0 0 0 3 4 0 0 5 18 4Aphredoderus sayanus Slack Water-Cervice 0 0 0 0 0 0 0 0 0 0 2 0 0 2 4 19 2Percina caprodes Swift Water-Sand and Gravel 0 1 11 11 0 17 0 0 0 0 0 8 2 0 4 20 17Cyprinella venusta Swift Water-Cervice 19 1 0 3 0 14 0 0 0 4 6 10 15 31 4 21 31Dorosoma petenense Slack Water-Open 0 0 0 0 0 0 0 0 0 3 1 0 0 0 4 22 3Percina macrolepida Swift Water-Vegitation 0 0 0 0 0 0 9 0 0 0 0 0 0 1 4 23 9Opsopoeodus emiliae Slack Water-Sand and Gravel 0 0 0 0 4 0 0 0 1 0 0 1 2 0 3 24 4Elassoma zonatum Slack Water-Vegitation 0 0 0 0 0 0 0 8 0 0 0 0 0 0 3 25 8Minytrema melanops Slack Water-Sand and Gravel 1 0 0 0 0 2 2 0 0 1 1 1 3 0 3 26 3Aplodinotus grunniens Swift Water-Open 0 0 0 0 0 0 0 0 0 0 1 0 1 0 3 27 1Etheostoma proeliare Slack Water-Cervice 0 0 0 5 0 0 0 0 7 0 0 0 0 0 2 28 7Pylodictis olivaris Slack Water-Cervice 0 0 0 0 0 0 0 0 0 0 1 0 1 0 2 29 1Pomoxis annularis Lacustrine/Generalist-Sand and Gravel 0 0 0 0 0 0 0 0 0 1 0 0 1 0 2 30 1Ammocrypta vivax Swift Water-Sand and Gravel 0 0 2 1 6 21 9 0 0 0 0 1 0 0 1 31 21Micropterus salmoides Lacustrine/Generalist-Sand and Gravel 0 3 0 0 0 0 0 0 0 1 1 2 5 0 1 32 5Pimephales vigilax Lacustrine/Generalist-Cervice 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 33 0Dorosoma cepedianum Lacustrine/Generalist-Open 0 1 0 0 0 0 0 0 0 1 1 0 3 0 1 34 3Etheostoma asprigene Slack Water-Sand and Gravel 0 0 0 8 1 0 5 0 0 0 0 0 0 0 1 35 8Etheostoma gracile Slack Water-Vegitation 0 0 0 0 0 0 0 0 1 0 0 0 0 1 1 36 1Ictiobus bubalus Slack Water-Vegitation 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 37 1Noturus nocturnus Swift Water-Sand and Gravel 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 38 1Notropis maculatus Slack Water-Vegitation 0 0 0 0 0 0 0 0 2 0 0 0 0 0 1 39 2Noturus gyrinus Slack Water-Cervice 0 0 0 0 0 0 2 0 0 0 0 0 0 0 1 40 2Ictiobus cyprinellus Slack Water-Vegitation 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 41 1Ictiobus niger Swift Water-Vegitation 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 41 1Amia calva Lacustrine/Generalist-Vegitation 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 43 0Pimephales promelas Slack Water-Sand and Gravel 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 44 0Pteronotropis hubbsi Slack Water-Sand and Gravel 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 45 2Lepomis cyanellus Lacustrine/Generalist-Sand and Gravel 1 0 0 0 0 0 0 0 0 0 0 1 0 1 0 46 1Lepisosteus osseus Swift Water-Vegitation 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 68 2Fundulus blairae Slack Water-Vegitation 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 69 1Semotilus atromaculatus Swift Water-Sand and Gravel 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 69 1Lythrurus umbratilis Slack Water-Sand and Gravel 1 0 0 0 0 0 0 0 4 0 0 0 0 0 0 71 4Lepomis Auritus Slack Water-Sand and Gravel 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 72 1Etheostoma histrio Swift Water-Sand and Gravel 0 0 0 14 0 5 0 0 0 0 0 0 0 2 0 73 14Percina maculata Swift Water-Sand and Gravel 0 0 0 14 0 0 2 0 0 0 0 0 0 0 -1 74 14Esox niger Slack Water-Vegitation 0 0 9 3 0 0 0 0 0 0 1 0 0 0 -1 75 9Hybognathus hayi Slack Water-Open 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1 76 0Hybognathus placitus Slack Water-Sand and Gravel 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1 76 0Percina shumardi Swift Water-Sand and Gravel 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1 76 0Esox americanus Slack Water-Vegitation 0 0 9 5 0 0 0 0 0 0 1 0 0 0 -1 79 9Etheostoma chlorosoma Slack Water-Vegitation 1 0 0 0 0 3 0 0 0 0 0 0 0 0 -1 80 3Notropis atrocaudalis Swift Water-Sand and Gravel 1 0 0 0 0 0 0 0 0 0 0 0 0 0 -4 81 1Etheostoma fusiforme Slack Water-Vegitation 2 0 0 0 0 0 0 0 0 0 0 0 0 0 -4 82 2Gambusia affinis Lacustrine/Generalist-Open 2 5 0 0 0 0 0 0 0 2 5 4 0 4 -5 83 5Lythrurus fumeus Slack Water-Open 0 1 2 4 2 21 0 0 0 0 0 0 0 0 -5 84 21Notropis atherinoides Swift Water-Open 3 0 0 0 0 0 0 0 0 0 0 0 0 0 -7 85 3Notropis chalybaeus Swift Water-Sand and Gravel 1 0 0 6 52 0 0 0 0 0 0 0 0 0 -9 86 52Notemigonus crysoleucas Lacustrine/Generalist-Vegitation 1 6 0 0 2 0 0 0 0 0 0 0 0 0 -17 87 6Cyprinella lutrensis Lacustrine/Generalist-Sand and Gravel 1 6 0 0 0 0 0 0 0 0 1 0 0 0 -18 88 6Hybognathus nuchalis Slack Water-Open 6 0 0 0 0 0 0 0 0 0 0 0 0 0 -20 89 6Hybopsis amnis Slack Water-Sand and Gravel 3 22 0 0 1 0 0 0 0 0 0 0 0 0 -63 90 22Notropis texanus Swift Water-Sand and Gravel 35 0 2 23 33 16 0 0 0 1 1 1 0 0 -108 91 35Notropis stramineus Swift Water-Sand and Gravel 2 44 0 0 0 0 0 0 0 0 0 0 0 0 -115 92 44
Appendix C 6
Existing PHABSIM data
+U
+U
+U
+U
[_
[_
[_
[_ [_ [_
Lake O' the PinesCadddo Lake
BL
LT 154
LT 3001
BG 3BG 2BG 1
Appendix C 7
BG01_BB
SLACK WATER SWIFT WATERSAND AND GRAVEL VEGITATION CERVICE SAND AND GRAVEL CERVICE
BB_DrySPOTTED SUCKER
SPOTTED BASS PICKEREL
BlUNTNOSE DARTER
FLATHEAD CATFISH
IRONCOLOR SHINER
BLACKSIDE DARTER
BLACKTAIL SHINER
Jan 90 82% 79% 93% 82% 53% 79% 94% 81%Feb 90 82% 79% 93% 82% 53% 79% 94% 81%Mar 218 96% 98% 89% 98% 69% 91% 84% 99%Apr 198 98% 99% 92% 100% 68% 94% 89% 100%May 114 88% 88% 97% 88% 61% 87% 98% 87%Jun 49 70% 65% 83% 69% 46% 66% 85% 66%Jul 13 57% 53% 66% 58% 37% 60% 77% 47%Aug 6 52% 49% 61% 50% 36% 56% 71% 41%Sep 6 52% 49% 61% 50% 36% 56% 71% 41%Oct 40 68% 62% 79% 66% 43% 66% 84% 62%Nov 90 82% 79% 93% 82% 53% 79% 94% 81%Dec 90 82% 79% 93% 82% 53% 79% 94% 81%
BB_AvgJan 268 91% 97% 77% 94% 68% 84% 72% 98%Feb 347 82% 93% 53% 86% 66% 73% 56% 91%Mar 390 77% 90% 42% 81% 65% 66% 49% 85%Apr 330 84% 94% 58% 88% 66% 76% 59% 93%May 150 97% 98% 99% 98% 69% 98% 100% 95%Jun 79 80% 77% 92% 78% 52% 79% 94% 78%Jul 35 66% 61% 77% 65% 42% 65% 84% 60%Aug 40 68% 62% 79% 66% 43% 66% 84% 62%Sep 40 68% 62% 79% 66% 43% 66% 84% 62%Oct 40 68% 62% 79% 66% 43% 66% 84% 62%Nov 90 82% 79% 93% 82% 53% 79% 94% 81%Dec 117 89% 89% 98% 89% 62% 89% 98% 88%
BB_WetJan 396 76% 89% 41% 80% 65% 65% 48% 84%Feb 500 65% 82% 28% 73% 67% 55% 38% 73%Mar 536 64% 79% 28% 73% 69% 52% 37% 73%Apr 445 71% 86% 35% 77% 65% 60% 43% 78%May 264 91% 97% 79% 94% 69% 84% 73% 98%Jun 140 95% 96% 99% 95% 68% 96% 100% 93%Jul 70 78% 74% 90% 75% 51% 76% 92% 75%Aug 41 68% 63% 80% 67% 44% 66% 85% 63%Sep 40 68% 62% 79% 66% 43% 66% 84% 62%Oct 49 70% 65% 83% 69% 46% 66% 85% 66%Nov 94 82% 80% 93% 84% 53% 80% 95% 82%Dec 275 90% 97% 75% 93% 68% 83% 70% 98%
BG01.xlsAppendix C 8
BG01_IHA
SLACK WATER SWIFT WATERSAND AND GRAVEL VEGITATION CERVICE SAND AND GRAVEL CERVICE
IHA_DrySPOTTED SUCKER
SPOTTED BASS PICKEREL
BlUNTNOSE DARTER
FLATHEAD CATFISH
IRONCOLOR SHINER
BLACKSIDE DARTER
BLACKTAIL SHINER
Jan 116 89% 89% 98% 89% 62% 89% 98% 87%Feb 195 98% 99% 93% 100% 68% 95% 90% 100%Mar 218 96% 98% 89% 98% 69% 90% 84% 99%Apr 198 98% 99% 93% 100% 68% 94% 89% 100%May 114 88% 88% 97% 88% 60% 87% 98% 87%Jun 49 70% 65% 83% 69% 46% 66% 85% 66%Jul 13 57% 53% 65% 58% 37% 60% 76% 47%Aug 6 52% 49% 60% 50% 36% 55% 71% 41%Sep 6 52% 49% 60% 49% 36% 55% 71% 40%Oct 6 52% 49% 61% 50% 36% 56% 71% 41%Nov 26 64% 58% 74% 63% 39% 64% 83% 56%Dec 61 75% 70% 87% 72% 49% 72% 89% 71%
IHA_AvgJan 268 91% 97% 77% 94% 68% 84% 72% 98%Feb 347 82% 93% 54% 86% 66% 73% 56% 91%Mar 389 77% 90% 42% 81% 65% 66% 49% 85%Apr 333 84% 93% 57% 87% 66% 75% 59% 93%May 150 97% 98% 99% 98% 69% 98% 100% 95%Jun 81 81% 78% 92% 79% 52% 79% 94% 79%Jul 39 67% 62% 79% 66% 43% 66% 84% 62%Aug 12 56% 52% 65% 57% 37% 60% 76% 46%Sep 12 57% 53% 65% 58% 37% 60% 76% 47%Oct 26 64% 58% 74% 63% 39% 64% 83% 56%Nov 56 73% 68% 85% 71% 48% 69% 87% 69%Dec 117 89% 89% 98% 89% 62% 89% 98% 88%
IHA_WetJan 396 76% 89% 41% 80% 65% 65% 48% 84%Feb 500 65% 82% 28% 73% 67% 55% 38% 73%Mar 536 64% 79% 28% 73% 69% 52% 37% 73%Apr 444 71% 86% 35% 77% 65% 60% 43% 78%May 264 91% 97% 79% 94% 69% 84% 73% 98%Jun 140 95% 96% 99% 95% 68% 96% 100% 93%Jul 70 78% 74% 89% 75% 51% 76% 92% 75%Aug 41 68% 63% 80% 67% 44% 66% 85% 63%Sep 32 65% 60% 76% 64% 41% 65% 84% 59%Oct 49 70% 65% 83% 69% 46% 66% 85% 66%Nov 94 82% 80% 93% 83% 53% 80% 95% 82%Dec 275 90% 97% 75% 93% 68% 83% 70% 98%
BG01.xlsAppendix C 9
BG01_POST
SLACK WATER SWIFT WATERSAND AND GRAVEL VEGITATION CERVICE SAND AND GRAVEL CERVICE
Post_DrySPOTTED SUCKER
SPOTTED BASS PICKEREL
BlUNTNOSE DARTER
FLATHEAD CATFISH
IRONCOLOR SHINER
BLACKSIDE DARTER
BLACKTAIL SHINER
Jan 33 66% 60% 77% 65% 41% 65% 84% 59%Feb 45 69% 64% 81% 68% 45% 66% 85% 64%Mar 41 68% 62% 79% 66% 44% 66% 84% 62%Apr 51 71% 66% 84% 69% 47% 67% 86% 67%May 41 68% 62% 79% 66% 44% 66% 84% 62%Jun 37 67% 61% 78% 65% 42% 65% 84% 61%Jul 29 65% 59% 75% 64% 40% 65% 84% 58%Aug 26 63% 58% 74% 63% 39% 64% 83% 56%Sep 26 64% 58% 74% 63% 39% 64% 83% 56%Oct 25 63% 58% 73% 63% 39% 64% 83% 56%Nov 24 63% 57% 73% 62% 39% 64% 83% 55%Dec 29 65% 59% 75% 64% 40% 65% 84% 58%
Post_AvgJan 105 85% 83% 95% 87% 56% 83% 96% 85%Feb 321 85% 94% 60% 89% 66% 77% 61% 94%Mar 165 99% 99% 98% 99% 69% 99% 99% 98%Apr 152 97% 99% 99% 98% 69% 98% 100% 96%May 56 73% 68% 85% 71% 48% 69% 87% 69%Jun 60 74% 70% 86% 72% 49% 71% 89% 70%Jul 65 76% 72% 88% 74% 50% 74% 91% 73%Aug 39 67% 62% 79% 66% 43% 66% 84% 62%Sep 41 68% 63% 80% 67% 44% 66% 85% 63%Oct 40 68% 62% 79% 66% 43% 66% 84% 62%Nov 40 68% 62% 79% 66% 43% 66% 84% 62%Dec 59 74% 69% 86% 72% 48% 71% 88% 70%
Post_WetJan 276 90% 97% 74% 93% 68% 83% 70% 98%Feb 481 67% 84% 31% 75% 66% 56% 40% 75%Mar 400 75% 89% 40% 80% 64% 64% 47% 83%Apr 293 88% 96% 68% 92% 67% 81% 66% 98%May 148 97% 98% 99% 97% 69% 98% 100% 95%Jun 197 98% 99% 93% 100% 68% 94% 89% 100%Jul 92 82% 79% 93% 83% 53% 79% 94% 82%Aug 60 74% 70% 86% 72% 49% 71% 89% 70%Sep 55 72% 67% 85% 70% 48% 69% 87% 68%Oct 63 75% 71% 87% 73% 49% 72% 90% 72%Nov 109 86% 85% 96% 87% 58% 85% 97% 86%Dec 341 83% 93% 55% 86% 66% 74% 57% 91%
BG01.xlsAppendix C 10
BG02_BB
SLACK WATER SWIFT WATERSAND AND GRAVEL VEGITATION CERVICE SAND AND GRAVEL CERVICE
BB_DrySPOTTED SUCKER
SPOTTED BASS PICKEREL
BlUNTNOSE DARTER
FLATHEAD CATFISH
IRONCOLOR SHINER
BLACKSIDE DARTER
BLACKTAIL SHINER
Jan 90 95% 98% 91% 98% 84% 90% 73% 99%Feb 90 95% 98% 91% 98% 84% 90% 73% 99%Mar 218 68% 88% 63% 68% 84% 68% 30% 89%Apr 198 74% 89% 67% 69% 84% 70% 33% 92%May 114 90% 95% 86% 90% 84% 84% 59% 99%Jun 49 98% 99% 100% 90% 82% 99% 99% 87%Jul 13 67% 67% 83% 70% 57% 74% 82% 61%Aug 6 55% 55% 69% 56% 47% 63% 74% 47%Sep 6 55% 55% 69% 56% 47% 63% 74% 47%Oct 40 90% 92% 97% 85% 76% 93% 95% 82%Nov 90 95% 98% 91% 98% 84% 90% 73% 99%Dec 90 95% 98% 91% 98% 84% 90% 73% 99%
BB_AvgJan 268 53% 86% 46% 65% 82% 62% 24% 80%Feb 347 37% 79% 29% 59% 81% 53% 20% 65%Mar 390 32% 76% 29% 56% 81% 48% 20% 60%Apr 330 39% 81% 29% 60% 81% 55% 20% 67%May 150 83% 93% 71% 79% 83% 78% 44% 98%Jun 79 99% 100% 92% 99% 83% 93% 81% 98%Jul 35 86% 87% 95% 82% 73% 89% 92% 79%Aug 40 90% 92% 97% 85% 76% 93% 95% 82%Sep 40 90% 92% 97% 85% 76% 93% 95% 82%Oct 40 90% 92% 97% 85% 76% 93% 95% 82%Nov 90 95% 98% 91% 98% 84% 90% 73% 99%Dec 117 89% 95% 86% 88% 84% 83% 57% 99%
BB_WetJan 396 31% 75% 29% 56% 81% 48% 20% 59%Feb 500 28% 70% 28% 59% 82% 43% 20% 53%Mar 536 28% 68% 29% 60% 84% 42% 19% 53%Apr 445 29% 73% 29% 57% 82% 45% 20% 56%May 264 54% 86% 48% 66% 82% 63% 24% 81%Jun 140 85% 93% 76% 81% 83% 79% 47% 98%Jul 70 100% 100% 94% 98% 83% 95% 87% 95%Aug 41 91% 92% 97% 85% 77% 94% 95% 83%Sep 40 90% 92% 97% 85% 76% 93% 95% 82%Oct 49 98% 99% 100% 90% 82% 99% 99% 87%Nov 94 94% 98% 90% 97% 84% 89% 70% 99%Dec 275 51% 85% 42% 65% 82% 61% 23% 78%
BG02.xlsAppendix C 11
BG02_IHA
SLACK WATER SWIFT WATERSAND AND GRAVEL VEGITATION CERVICE SAND AND GRAVEL CERVICE
IHA_DrySPOTTED SUCKER
SPOTTED BASS PICKEREL
BlUNTNOSE DARTER
FLATHEAD CATFISH
IRONCOLOR SHINER
BLACKSIDE DARTER
BLACKTAIL SHINER
Jan 116 89% 95% 86% 89% 84% 84% 58% 99%Feb 195 74% 89% 68% 70% 84% 71% 34% 92%Mar 218 68% 88% 63% 68% 84% 68% 30% 89%Apr 198 74% 89% 68% 69% 84% 70% 33% 92%May 114 90% 96% 86% 90% 84% 84% 59% 99%Jun 49 98% 99% 100% 90% 82% 99% 99% 87%Jul 13 67% 67% 82% 70% 57% 74% 82% 61%Aug 6 55% 54% 69% 56% 47% 63% 74% 46%Sep 6 54% 54% 68% 55% 47% 62% 73% 46%Oct 6 55% 55% 69% 56% 47% 63% 74% 47%Nov 26 78% 80% 92% 76% 67% 83% 88% 74%Dec 61 100% 100% 97% 95% 83% 97% 93% 92%
IHA_AvgJan 268 53% 86% 46% 65% 82% 62% 24% 80%Feb 347 37% 79% 29% 59% 81% 53% 20% 65%Mar 389 32% 76% 29% 56% 81% 48% 20% 60%Apr 333 39% 81% 29% 60% 81% 54% 20% 67%May 150 83% 93% 71% 79% 83% 78% 44% 98%Jun 81 98% 99% 92% 99% 83% 92% 80% 98%Jul 39 90% 91% 97% 84% 76% 92% 94% 81%Aug 12 66% 66% 81% 69% 56% 73% 82% 60%Sep 12 66% 67% 82% 70% 57% 74% 82% 60%Oct 26 78% 80% 92% 76% 67% 83% 88% 74%Nov 56 99% 100% 98% 93% 83% 99% 96% 90%Dec 117 89% 95% 86% 88% 84% 83% 57% 99%
IHA_WetJan 396 31% 75% 29% 56% 81% 48% 20% 59%Feb 500 28% 70% 28% 59% 82% 43% 20% 53%Mar 536 28% 68% 29% 60% 84% 42% 19% 53%Apr 444 29% 73% 29% 57% 82% 45% 20% 56%May 264 54% 86% 49% 66% 82% 63% 24% 81%Jun 140 85% 93% 77% 81% 83% 79% 48% 98%Jul 70 100% 100% 94% 98% 83% 95% 88% 95%Aug 41 91% 92% 97% 85% 77% 94% 95% 83%Sep 32 83% 85% 94% 79% 71% 87% 91% 77%Oct 49 98% 99% 100% 90% 82% 99% 99% 87%Nov 94 94% 98% 90% 97% 84% 89% 71% 99%Dec 275 51% 85% 43% 65% 82% 61% 23% 78%
BG02.xlsAppendix C 12
BG02_POST
SLACK WATER SWIFT WATERSAND AND GRAVEL VEGITATION CERVICE SAND AND GRAVEL CERVICE
Post_DrySPOTTED SUCKER
SPOTTED BASS PICKEREL
BlUNTNOSE DARTER
FLATHEAD CATFISH
IRONCOLOR SHINER
BLACKSIDE DARTER
BLACKTAIL SHINER
Jan 33 85% 86% 95% 81% 72% 88% 91% 78%Feb 45 94% 95% 98% 88% 79% 96% 97% 85%Mar 41 91% 92% 97% 85% 77% 93% 95% 82%Apr 51 99% 100% 100% 91% 83% 100% 99% 88%May 41 91% 92% 97% 85% 77% 93% 95% 82%Jun 37 87% 89% 96% 83% 74% 90% 93% 80%Jul 29 81% 83% 93% 78% 69% 85% 89% 75%Aug 26 78% 80% 92% 76% 67% 83% 87% 73%Sep 26 78% 80% 92% 76% 67% 83% 88% 74%Oct 25 77% 79% 92% 75% 66% 82% 87% 73%Nov 24 76% 78% 91% 75% 65% 81% 87% 72%Dec 29 81% 83% 93% 78% 69% 85% 89% 75%
Post_AvgJan 105 91% 97% 88% 94% 84% 87% 63% 100%Feb 321 41% 82% 29% 60% 81% 56% 20% 68%Mar 165 80% 91% 71% 75% 83% 75% 42% 96%Apr 152 82% 92% 71% 78% 83% 77% 43% 98%May 56 99% 100% 98% 93% 83% 99% 96% 90%Jun 60 99% 100% 97% 94% 83% 98% 94% 92%Jul 65 100% 100% 96% 96% 83% 96% 91% 94%Aug 39 90% 91% 97% 84% 76% 92% 94% 81%Sep 41 92% 93% 97% 86% 77% 94% 96% 83%Oct 40 90% 91% 97% 84% 76% 93% 95% 82%Nov 40 90% 91% 97% 84% 76% 93% 95% 82%Dec 59 99% 100% 98% 94% 83% 98% 95% 91%
Post_WetJan 276 51% 85% 42% 64% 82% 61% 23% 77%Feb 481 28% 71% 28% 59% 82% 44% 20% 54%Mar 400 31% 75% 29% 56% 81% 47% 20% 58%Apr 293 46% 84% 33% 62% 82% 59% 20% 73%May 148 83% 93% 73% 79% 83% 78% 45% 98%Jun 197 74% 89% 68% 69% 84% 70% 33% 92%Jul 92 95% 98% 91% 97% 84% 90% 72% 99%Aug 60 99% 100% 97% 94% 83% 98% 94% 92%Sep 55 99% 100% 99% 93% 83% 99% 97% 90%Oct 63 100% 100% 96% 96% 83% 97% 92% 93%Nov 109 91% 96% 87% 92% 84% 85% 61% 100%Dec 341 38% 80% 29% 59% 81% 53% 20% 66%
BG02.xlsAppendix C 13
BG03_IHA
SLACK WATER SWIFT WATERSAND AND GRAVEL VEGITATION CERVICE SAND AND GRAVEL CERVICE
IHA_DrySPOTTED SUCKER
SPOTTED BASS PICKEREL
BlUNTNOSE DARTER
FLATHEAD CATFISH
IRONCOLOR SHINER
BLACKSIDE DARTER
BLACKTAIL SHINER
Jan 116 98% 99% 88% 95% 90% 96% 97% 97%Feb 195 95% 100% 94% 97% 91% 100% 99% 97%Mar 218 93% 100% 94% 96% 91% 100% 98% 96%Apr 198 95% 100% 94% 97% 91% 100% 99% 97%May 114 98% 99% 88% 95% 90% 97% 97% 97%Jun 49 100% 97% 97% 90% 89% 95% 100% 96%Jul 13 99% 93% 92% 89% 85% 86% 96% 95%Aug 6 100% 92% 86% 89% 84% 84% 94% 95%Sep 6 100% 92% 85% 89% 84% 84% 94% 95%Oct 6 100% 92% 86% 89% 84% 85% 94% 95%Nov 26 100% 95% 94% 90% 87% 91% 99% 95%Dec 61 99% 98% 98% 91% 89% 95% 100% 96%
IHA_AvgJan 268 90% 99% 93% 95% 91% 98% 96% 95%Feb 347 91% 99% 90% 95% 92% 96% 96% 95%Mar 389 92% 99% 88% 95% 93% 96% 96% 96%Apr 333 91% 99% 91% 95% 92% 96% 95% 95%May 150 97% 99% 91% 96% 90% 98% 98% 97%Jun 81 98% 99% 96% 93% 90% 96% 100% 96%Jul 39 100% 96% 96% 90% 88% 93% 99% 96%Aug 12 99% 93% 92% 89% 85% 86% 96% 94%Sep 12 99% 93% 92% 89% 85% 86% 96% 95%Oct 26 100% 95% 94% 90% 87% 91% 99% 95%Nov 56 99% 98% 97% 90% 89% 95% 100% 96%Dec 117 97% 99% 88% 95% 90% 96% 97% 97%
IHA_WetJan 396 92% 99% 88% 95% 93% 95% 96% 97%Feb 500 91% 99% 93% 97% 95% 96% 90% 98%Mar 536 90% 99% 95% 98% 95% 95% 89% 99%Apr 444 91% 99% 90% 96% 94% 96% 93% 97%May 264 90% 99% 93% 95% 91% 98% 96% 95%Jun 140 97% 99% 89% 95% 90% 97% 97% 96%Jul 70 99% 98% 98% 91% 90% 95% 100% 96%Aug 41 100% 97% 96% 90% 88% 93% 99% 96%Sep 32 100% 96% 95% 90% 87% 92% 99% 95%Oct 49 100% 97% 97% 90% 89% 95% 100% 96%Nov 94 99% 99% 92% 94% 90% 97% 99% 97%Dec 275 90% 99% 93% 95% 91% 98% 96% 95%
BG03.xlsAppendix C 14
BG03_BB
SLACK WATER SWIFT WATERSAND AND GRAVEL VEGITATION CERVICE SAND AND GRAVEL CERVICE
BB_DrySPOTTED SUCKER
SPOTTED BASS PICKEREL
BlUNTNOSE DARTER
FLATHEAD CATFISH
IRONCOLOR SHINER
BLACKSIDE DARTER
BLACKTAIL SHINER
Jan 90 99% 99% 93% 94% 90% 97% 99% 97%Feb 90 99% 99% 93% 94% 90% 97% 99% 97%Mar 218 93% 100% 94% 96% 91% 100% 98% 96%Apr 198 95% 100% 94% 97% 91% 100% 99% 97%May 114 98% 99% 88% 95% 90% 97% 97% 97%Jun 49 100% 97% 97% 90% 89% 95% 100% 96%Jul 13 99% 93% 92% 89% 85% 87% 96% 95%Aug 6 100% 92% 86% 89% 84% 84% 94% 95%Sep 6 100% 92% 86% 89% 84% 84% 94% 95%Oct 40 100% 96% 96% 90% 88% 93% 99% 96%Nov 90 99% 99% 93% 94% 90% 97% 99% 97%Dec 90 99% 99% 93% 94% 90% 97% 99% 97%
BB_AvgJan 268 90% 99% 93% 95% 91% 98% 96% 95%Feb 347 91% 99% 90% 95% 92% 96% 96% 95%Mar 390 92% 99% 88% 95% 93% 96% 96% 96%Apr 330 91% 99% 91% 95% 92% 96% 95% 95%May 150 97% 99% 91% 96% 90% 98% 98% 97%Jun 79 98% 99% 97% 92% 90% 96% 100% 96%Jul 35 100% 96% 95% 90% 88% 92% 99% 95%Aug 40 100% 96% 96% 90% 88% 93% 99% 96%Sep 40 100% 96% 96% 90% 88% 93% 99% 96%Oct 40 100% 96% 96% 90% 88% 93% 99% 96%Nov 90 99% 99% 93% 94% 90% 97% 99% 97%Dec 117 97% 99% 88% 95% 90% 96% 97% 97%
BB_WetJan 396 92% 99% 88% 95% 93% 95% 96% 97%Feb 500 91% 99% 93% 97% 95% 96% 90% 98%Mar 536 90% 99% 95% 98% 95% 95% 89% 99%Apr 445 91% 99% 90% 96% 94% 96% 93% 97%May 264 90% 99% 93% 95% 91% 98% 96% 95%Jun 140 97% 99% 90% 95% 90% 97% 97% 96%Jul 70 99% 98% 98% 91% 90% 95% 100% 96%Aug 41 100% 97% 96% 90% 88% 93% 99% 96%Sep 40 100% 96% 96% 90% 88% 93% 99% 96%Oct 49 100% 97% 97% 90% 89% 95% 100% 96%Nov 94 99% 99% 91% 94% 90% 97% 99% 97%Dec 275 90% 99% 93% 95% 91% 98% 96% 95%
BG03.xlsAppendix C 15
BG03_POST
SLACK WATER SWIFT WATERSAND AND GRAVEL VEGITATION CERVICE SAND AND GRAVEL CERVICE
Post_DrySPOTTED SUCKER
SPOTTED BASS PICKEREL
BlUNTNOSE DARTER
FLATHEAD CATFISH
IRONCOLOR SHINER
BLACKSIDE DARTER
BLACKTAIL SHINER
Jan 33 100% 96% 95% 90% 87% 92% 99% 95%Feb 45 100% 97% 96% 90% 88% 94% 100% 96%Mar 41 100% 96% 96% 90% 88% 93% 99% 96%Apr 51 100% 97% 97% 90% 89% 95% 100% 96%May 41 100% 96% 96% 90% 88% 93% 99% 96%Jun 37 100% 96% 95% 90% 88% 93% 99% 96%Jul 29 100% 95% 94% 90% 87% 91% 99% 95%Aug 26 100% 95% 94% 90% 87% 91% 99% 95%Sep 26 100% 95% 94% 90% 87% 91% 99% 95%Oct 25 100% 95% 94% 90% 87% 91% 99% 95%Nov 24 100% 95% 93% 89% 87% 90% 98% 95%Dec 29 100% 95% 94% 90% 87% 91% 99% 95%
Post_AvgJan 105 99% 99% 89% 95% 90% 98% 98% 97%Feb 321 90% 99% 91% 95% 92% 96% 95% 95%Mar 165 96% 100% 92% 97% 91% 99% 98% 97%Apr 152 96% 99% 91% 96% 90% 98% 98% 97%May 56 99% 98% 97% 90% 89% 95% 100% 96%Jun 60 99% 98% 98% 91% 89% 95% 100% 96%Jul 65 99% 98% 98% 91% 89% 95% 100% 96%Aug 39 100% 96% 96% 90% 88% 93% 99% 96%Sep 41 100% 97% 96% 90% 88% 93% 99% 96%Oct 40 100% 96% 96% 90% 88% 93% 99% 96%Nov 40 100% 96% 96% 90% 88% 93% 99% 96%Dec 59 99% 98% 97% 90% 89% 95% 100% 96%
Post_WetJan 276 90% 99% 93% 95% 91% 98% 96% 95%Feb 481 91% 99% 92% 97% 94% 96% 91% 98%Mar 400 92% 99% 88% 95% 93% 95% 96% 97%Apr 293 90% 99% 93% 95% 91% 97% 95% 94%May 148 97% 99% 90% 96% 90% 98% 98% 97%Jun 197 95% 100% 94% 97% 91% 100% 99% 97%Jul 92 99% 99% 92% 94% 90% 97% 99% 97%Aug 60 99% 98% 98% 91% 89% 95% 100% 96%Sep 55 99% 98% 97% 90% 89% 95% 100% 96%Oct 63 99% 98% 98% 91% 89% 95% 100% 96%Nov 109 98% 99% 89% 95% 90% 97% 98% 97%Dec 341 91% 99% 90% 95% 92% 96% 95% 95%
BG03.xlsAppendix C 16
LT154
SLACK WATER SWIFT WATERSAND AND GRAVEL VEGITATION CERVICE SAND AND GRAVEL CERVICE
BB_DrySPOTTED SUCKER
SPOTTED BASS PICKEREL
BlUNTNOSE DARTER
FLATHEAD CATFISH
IRONCOLOR SHINER
BLACKSIDE DARTER
BLACKTAIL SHINER
Jan 112 76% 83% 36% 62% 63% 65% 66% 53%Feb 186 96% 97% 72% 95% 97% 93% 96% 81%Mar 219 99% 99% 72% 99% 95% 96% 99% 92%Apr 158 92% 94% 64% 89% 91% 86% 89% 69%May 86 72% 82% 26% 54% 52% 62% 61% 52%Jun 38 72% 87% 52% 69% 68% 85% 77% 71%Jul 12 65% 77% 99% 86% 95% 97% 94% 70%Aug 5 54% 63% 85% 74% 87% 81% 79% 47%Sep 5 54% 63% 85% 74% 87% 81% 79% 47%Oct 5 54% 63% 85% 74% 87% 81% 79% 47%Nov 18 69% 81% 90% 83% 89% 98% 93% 76%Dec 68 71% 84% 27% 56% 52% 67% 64% 57%
BB_AvgJan 242 100% 100% 67% 100% 90% 96% 98% 98%Feb 417 95% 96% 34% 85% 76% 61% 67% 83%Mar 415 95% 96% 34% 85% 76% 61% 67% 83%Apr 287 98% 99% 49% 90% 79% 82% 82% 98%May 155 92% 94% 63% 89% 90% 85% 88% 68%Jun 96 72% 80% 28% 54% 53% 60% 60% 49%Jul 26 70% 84% 73% 75% 78% 93% 86% 76%Aug 10 63% 74% 100% 85% 95% 95% 93% 66%Sep 10 63% 74% 100% 85% 95% 95% 93% 66%Oct 19 69% 81% 87% 82% 88% 97% 92% 77%Nov 65 72% 84% 28% 57% 53% 68% 65% 58%Dec 144 89% 92% 58% 83% 85% 81% 83% 64%
BB_WetJan 462 91% 91% 31% 80% 73% 55% 62% 81%Feb 570 83% 78% 24% 67% 64% 42% 50% 76%Mar 548 85% 81% 26% 70% 66% 45% 52% 77%Apr 466 91% 90% 31% 79% 72% 55% 61% 81%May 320 97% 98% 42% 86% 76% 74% 75% 95%Jun 179 95% 96% 70% 94% 95% 91% 94% 78%Jul 80 71% 82% 24% 54% 51% 63% 62% 53%Aug 30 71% 85% 65% 72% 74% 90% 82% 74%Sep 33 71% 86% 60% 70% 72% 88% 80% 73%Oct 53 72% 86% 36% 62% 58% 74% 69% 63%Nov 133 84% 89% 50% 76% 77% 76% 77% 60%Dec 250 100% 100% 65% 100% 88% 96% 98% 100%
LT154.xlsAppendix C 17
LT3001
SLACK WATER SWIFT WATERSAND AND GRAVEL VEGITATION CERVICE SAND AND GRAVEL CERVICE
BB_DrySPOTTED SUCKER
SPOTTED BASS PICKEREL
BlUNTNOSE DARTER
FLATHEAD CATFISH
IRONCOLOR SHINER
BLACKSIDE DARTER
BLACKTAIL SHINER
Jan 112 85% 90% 89% 86% 87% 89% 87% 77%Feb 186 99% 99% 100% 99% 99% 100% 99% 97%Mar 219 98% 98% 89% 93% 93% 95% 94% 98%Apr 158 97% 98% 100% 100% 100% 100% 98% 91%May 86 74% 79% 75% 75% 72% 78% 76% 71%Jun 38 57% 58% 66% 63% 53% 64% 62% 66%Jul 12 43% 43% 54% 55% 41% 56% 56% 45%Aug 5 33% 34% 41% 40% 34% 45% 46% 28%Sep 5 33% 34% 41% 40% 34% 45% 46% 28%Oct 5 33% 34% 41% 40% 34% 45% 46% 28%Nov 18 46% 46% 57% 56% 43% 57% 57% 52%Dec 68 66% 69% 65% 68% 61% 70% 67% 69%
BB_AvgJan 242 96% 96% 77% 86% 87% 89% 86% 95%Feb 417 82% 79% 25% 62% 63% 53% 54% 70%Mar 415 82% 79% 25% 62% 63% 53% 55% 70%Apr 287 95% 94% 54% 79% 78% 81% 77% 89%May 155 97% 98% 100% 100% 100% 100% 98% 90%Jun 96 79% 85% 82% 80% 80% 83% 81% 72%Jul 26 52% 52% 63% 60% 48% 61% 61% 60%Aug 10 43% 42% 53% 54% 41% 56% 56% 42%Sep 10 43% 42% 53% 54% 41% 56% 56% 42%Oct 19 47% 47% 57% 56% 43% 57% 57% 53%Nov 65 65% 68% 64% 67% 60% 68% 66% 69%Dec 144 94% 97% 98% 98% 98% 98% 96% 87%
BB_WetJan 462 77% 72% 20% 57% 59% 46% 48% 65%Feb 570 63% 57% 7% 45% 50% 29% 34% 55%Mar 548 66% 60% 10% 48% 52% 32% 37% 57%Apr 466 76% 72% 19% 57% 59% 45% 48% 65%May 320 93% 91% 44% 74% 74% 74% 71% 84%Jun 179 98% 99% 100% 99% 99% 100% 99% 95%Jul 80 72% 76% 70% 72% 68% 75% 73% 70%Aug 30 53% 53% 63% 60% 48% 61% 60% 62%Sep 33 55% 55% 65% 61% 50% 62% 61% 63%Oct 53 61% 62% 62% 65% 55% 64% 62% 68%Nov 133 91% 94% 95% 94% 94% 95% 93% 83%Dec 250 96% 95% 72% 84% 85% 87% 84% 94%
LT3001.xlsAppendix C 18
BL
SLACK WATER SWIFT WATERSAND AND GRAVEL VEGITATION CERVICE SAND AND GRAVEL CERVICE
BB_DrySPOTTED SUCKER
SPOTTED BASS PICKEREL
BlUNTNOSE DARTER
FLATHEAD CATFISH
IRONCOLOR SHINER
BLACKSIDE DARTER
BLACKTAIL SHINER
Jan 125 95% 99% 62% 89% 87% 71% 67% 76%Feb 201 97% 96% 60% 94% 91% 69% 65% 80%Mar 242 97% 97% 65% 92% 96% 68% 65% 82%Apr 140 97% 100% 62% 93% 88% 72% 68% 77%May 80 89% 93% 54% 81% 77% 67% 62% 74%Jun 42 91% 95% 66% 90% 79% 78% 75% 83%Jul 11 85% 87% 95% 94% 86% 94% 90% 85%Aug 4 81% 84% 100% 98% 93% 100% 100% 75%Sep 4 81% 84% 100% 98% 93% 100% 100% 75%Oct 4 81% 84% 100% 98% 93% 100% 100% 75%Nov 19 89% 92% 80% 94% 86% 88% 85% 86%Dec 91 91% 96% 58% 81% 82% 68% 64% 74%
BB_AvgJan 222 97% 96% 63% 93% 93% 69% 65% 81%Feb 300 99% 98% 68% 96% 100% 70% 68% 87%Mar 306 100% 98% 68% 96% 100% 70% 68% 87%Apr 205 97% 96% 61% 94% 91% 69% 65% 80%May 156 98% 100% 62% 96% 89% 73% 68% 78%Jun 95 92% 97% 60% 81% 84% 68% 65% 74%Jul 32 91% 94% 70% 91% 82% 81% 78% 84%Aug 5 82% 84% 99% 97% 92% 99% 98% 76%Sep 4 81% 84% 100% 98% 93% 100% 100% 75%Oct 13 87% 89% 92% 94% 87% 92% 89% 86%Nov 74 88% 92% 52% 81% 75% 67% 62% 74%Dec 209 97% 96% 61% 94% 92% 69% 65% 80%
BB_WetJan 322 100% 98% 68% 97% 99% 70% 68% 88%Feb 366 100% 96% 69% 99% 98% 71% 67% 92%Mar 382 100% 96% 69% 99% 98% 71% 66% 93%Apr 327 100% 97% 68% 97% 99% 70% 67% 89%May 210 97% 96% 61% 94% 92% 69% 65% 80%Jun 191 97% 97% 60% 94% 90% 70% 66% 79%Jul 63 91% 95% 58% 86% 78% 73% 68% 78%Aug 14 87% 89% 91% 93% 87% 91% 88% 86%Sep 19 89% 92% 80% 94% 86% 88% 85% 86%Oct 45 92% 95% 65% 89% 78% 77% 74% 82%Nov 158 97% 99% 62% 96% 89% 73% 68% 78%Dec 294 99% 98% 68% 96% 99% 70% 68% 86%
BL.xlsAppendix C 19
DRAFT
Appendix D 1
APPENDIX D ATTAINMENT TARGETS {A draft of this document entitled Draft Discussion Paper on Water Availability was provided at the Third flows
workshop in December 2008}
The policy approach to evaluating compliance with instream flow requirements is currently undergoing transition
in Texas. Traditionally instream flow requirements have been included in water rights permits as special conditions
that limited diversions subject to the maintenance of these “minimum” flows. With the passage of SB3, the TCEQ
was directed to determine a flow reservation through rule making.
On the scientific side, a general understanding has developed that the concept of a minimum flow is not sufficient
to protect the ecological health of a river. This view, supported by the recent National Academy of Sciences review
of the Texas Instream Flow Program recognizes that healthy rivers require a full range of flows, including natural
variability.
The Cypress Flows Project (CFP) recognizes these current science and policy perspectives and has developed the
first steps for an SB 3 type of flow reservation. Water availability analysis tools and implementation options
needed to convert the flow components of the regime into a reservation or set aside have not yet been fully
developed by TCEQ. Thus, the CFP has begun developing some options and tools to investigate these issues in the
Cypress basin.
Monthly Water Availability Analysis
One important disconnect between the traditional analysis of availability in Texas and current understanding of
instream flow requirements is the use of a monthly Water Availability Model (WAM). The WAM is a FORTRAN
based computer model that implements the prior appropriation doctrine for the Cypress basin. Calculations are
performed by overlaying current water rights on historical hydrology to predict available diversions and resulting
river flows on a monthly time step. A monthly timestep is not suitable for determining impacts on environmental
flows; the ecosystem responds to instream flows on much shorter time step. This is particularly true for short
duration high flow pulse and flood flows. For example a 6,000 cubic feet per second (cfs) pulse event is
indistinguishable in the WAM from a constant average flow of 200 cfs for 30 days, however these regimes result in
very different biological responses. An analogous situation occurs at the low flow end where a month of extremely
low flows can be masked by short duration high flow events.
One option for addressing this problem is to develop a daily time step WAM. Some effort has been made towards
this objective; however, the daily datasets necessary to drive a daily model have not yet been developed. A second
option is to scale the daily targets up to monthly, while recognizing the inherent problem described above, in order
to make a gross evaluation of how well the system meets the instream flow needs and conversely what impact
meeting these instream targets would have on future water rights. A third option is to convert monthly outputs
into a daily time series based on a daily distribution pattern from a suitable reference gage.
Applying this second option to the current flow regimes for the Cypress Basin, the first step is to convert the
instantaneous flow rates in cfs into a monthly volume of acre‐feet (ACFT). Recall that the building blocks developed
by the CFP included targets for dry, average and wet conditions, thus three sets of monthly volumes were
developed for each creek. The WAM includes the years 1948‐1998 (51 years or 612 months).
Table 1 shows the frequency of meeting the flows proposed in the building blocks on a monthly volumetric, basis.
This table and subsequent tables display results for three scenarios. The first column “Naturalized” represents the
DRAFT
Appendix D 2
flows that would have occurred in the absence of man’s activities. Typically, naturalized flows are developed from
USGS gages by making adjustments based on upstream diversions and returns. The “Current Conditions”
simulation, as the name implies, is intended to represent the flow that would occur assuming current levels of
withdrawals and returns. This alternative could be useful in helping to identify water that has been permitted but
is not currently being fully utilized. The “Full Authorization” simulation includes maximum permitted withdrawals
and assumes 100% reuse; no return flows. This very conservative approach ensures that TCEQ does not grant
permits that would overappropriate the basin, but does not represent a very realistic portrayal of current or even
future conditions. TCEQ uses the fully appropriated simulation to consider water availability for new water
applications.
Table 1 Annual frequency of meeting initial building blocks targets for base flows
These results show that for Black and Little Cypress the dry condition targets are met or exceeded about 80% of
the time, the average targets about 70% of the time and wet targets about 50% of the time under natural and
regulated conditions. Given the relatively small quantity of water diversions from these two creeks, this is not
surprising. The difference between 83% and 81% for Little Cypress means that there were just 12 months out of
612 during which natural monthly flows would have met the base dry target while flows resulting from the full
authorization simulation would not. The shortfalls during these months ranged from 51 ACFT/Month (about 0.8
cfs) to 1,720 ACFT/Month (about 30 cfs). Ten of the 12 months had shortfalls less than 1,000 ACFT/Month (about
15 cfs).
The analysis of flows for Big Cypress shows the impact of Lake O’ the Pines (LOP). While naturalized flows show a
pattern similar to the other two tributaries, regulated flows, assuming full authorization and zero return flows,
indicate a substantial decrease, over 50%, in the frequency of meeting the targets under the full authorization
simulation. Since the WAM is based on the prior appropriation doctrine, whenever LOP (priority date 1959) is not
full or spilling, no water is released except for water rights with a senior date. Zero flow months predicted by the
WAM are not that uncommon ‐ about 11% of the months – and there are many months (~75%) in which flows are
predicted to average less than 6 cfs (the lowest value in the initial recommendations). There are a number of
reasons for these results including
1. the rather conservative assumptions used in water rights permitting, e.g. full authorization and zero
return flows,
2. the fact that the model does not show releases for downstream contracts; therefore the entire LOP
permitted withdrawals are assumed to occur lake side (Currently NETMWD has a contract for 9,000 ACFT
to supply water to Marshall which diverts from Big Cypress below LOP however since this is a contract,
this diversion is assumed to occur lakeside and thus is not reflected in the WAM at the Big Cypress gage
location), and
3. the WAM does not include any conditions not explicitly included in state water rights permits thus does
not include the minimum 5 cfs flow release required for LOP (This 5 cfs flow requirement is mandated by
federal law and could not be violated even if the Cypress Flows Project were to recommend lower flows).
Dry Average Wet
Site NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
AuthorizationBig Cypress Creek 78% 50% 23% 67% 41% 19% 60% 37% 17%Little Cypress Creek 82% 83% 81% 71% 71% 69% 53% 53% 52%Black Cypress Bayou 79% 79% 79% 66% 66% 66% 52% 52% 52%
DRAFT
Appendix D 3
While the initial building blocks were derived from low flow percentiles, the frequency at which these targets
should be achieved was not explicitly defined. There are a number of reasonable options that could be proposed.
For example, every period could be designated as either dry, average or wet; dry implying the driest third of the
time, average the middle third and wet the wettest third, which translates to dry should be met 100% of the time,
average at least 66% of the time, and wet at least 33% of the time. A second option could be that the targets
should be met at their natural frequency (or perhaps some acceptable level below that frequency in
acknowledgement of the impact of development). From Table 1 that would mean that dry should be met or
exceeded about 80% of the time, average about 70% of the time, and wet about 50% of the time. (Note that these
percentiles differ from the 75th, 50th and 25th low flow statistics used in the building blocks. The discrepancies are
due to two factors. First, the percentiles were based on flow separated, low flow conditions and thus do not
include the percent of the time when the flows were high. (See IHA flow separation algorithm, TNC 2007) Second,
the results in Table 1 represent frequencies based on the WAM simulated flows for the period from 1948‐1998
while the base flow recommendations were derived for gaged pre‐LOP flows from 1924‐1959.) One should also
note that this second option for desired frequencies would imply that there would be times that flows would fall
below the dry target levels, as they have naturally. That might suggest the need for subsistence targets or an
absolute minimum that flows should never violate. Finally, these issues might be viewed differently for regulated
versus unregulated systems. For example while it is possible to ensure an absolute minimum flow (base‐dry or
subsistence) on Big Cypress via reservoir releases, that option is not available on the unregulated streams.
A more sophisticated analysis (presented in Table 2 – Big Cypress only, statistics for Little and Black are included in
the appendices) evaluates the frequency of meeting the various targets for each month.
Table 2 Monthly frequency of meeting initial building blocks targets for base flows in Big Cypress
It is notable that some of the lowest frequencies occur in months for which initial building blocks were adjusted
upward based on professional judgment and review of existing instream flow studies. Nonetheless, this analysis
supports the conclusion that based on existing water availability modeling, the building blocks targets would not
be met at the desired frequencies under either of the options described above. The results also suggest that there
is substantial unperfected water. This water, which has been permitted but currently is not being diverted or is
not being reused, is reflected in the current conditions simulation. Significant increases in the frequencies of
meeting the initial recommendations could be achieved by dedicating some of this water to meet instream flow
needs.
Base Flow Targets Percent ExcedenceDry Average Wet
NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
AuthorizationJan 92% 65% 29% 75% 49% 29% 61% 41% 27%Feb 98% 75% 37% 80% 63% 33% 75% 57% 31%Mar 94% 75% 45% 80% 67% 43% 73% 63% 31%Apr 88% 71% 35% 76% 63% 33% 71% 57% 25%May 86% 71% 33% 78% 71% 33% 75% 65% 29%Jun 80% 51% 24% 78% 47% 22% 71% 45% 20%Jul 73% 22% 8% 59% 16% 4% 45% 10% 4%
Aug 57% 31% 16% 31% 6% 0% 31% 6% 0%Sep 61% 37% 20% 39% 12% 6% 39% 12% 6%Oct 55% 18% 2% 55% 18% 2% 51% 16% 0%Nov 71% 31% 10% 71% 31% 10% 71% 31% 10%Dec 82% 49% 16% 75% 49% 16% 57% 47% 14%
All Months 78% 50% 23% 67% 41% 19% 60% 37% 17%
DRAFT
Appendix D 4
Daily Water Availability Analysis
Although daily time step WAMs have not yet been developed for the Cypress basin, it is possible to convert the
monthly outputs from the WAM into daily flow estimates. This is accomplished by applying a flow distribution
pattern to the monthly values to distribute these monthly volumes to daily flow rates. For Little and Black Cypress,
which have only been moderately altered, this is a straightforward exercise commonly applied in water planning.
Daily gage records for a given month are used to pro‐rate the monthly flows from the WAM.
In the case of Big Cypress, where flow has been substantially altered, the issue is slightly more complicated. When
distributing monthly‐naturalized flows to daily, it does not make sense to use the pattern produced at a regulated
flow gage. Likewise, for regulated flows, it does not make sense to apply a natural flow pattern to produce
regulated daily flows. For this analysis, if the appropriate distribution pattern was not available, flows were
distributed based on a pattern derived from another time period but for which the total monthly flows were
roughly the same.
Once daily flows are produced for natural and regulated simulations, the frequencies and durations of meeting
each of the flow components defined in the building blocks can be assessed including the sub‐monthly high flow
targets. Table 3 presents the results of this daily analysis.
Table 3 frequency of meeting initial building blocks targets for base, pulse and flood flows in Big Cypress.
For the base flow targets, these results suggest that the monthly analysis presented above slightly over estimate
the frequency of meeting the targets. The monthly analysis over predicts the frequency of meeting the targets by
about 5 %, for example the June base average target is met 80% of the time according to the monthly analysis but
only 75% of the time in the daily analysis. Figure 1 provides and illustrative example to explain this difference.
Base Flow Targets Percent ExcedenceDry Average Wet
NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
AuthorizationJan 90% 57% 24% 66% 42% 19% 56% 38% 16%Feb 98% 63% 29% 77% 54% 21% 68% 49% 16%Mar 88% 61% 30% 76% 55% 22% 68% 51% 18%Apr 79% 57% 24% 69% 53% 20% 62% 49% 16%May 77% 59% 27% 72% 57% 24% 64% 54% 23%Jun 75% 47% 15% 68% 37% 14% 56% 31% 11%Jul 67% 22% 8% 50% 15% 7% 38% 10% 5%
Aug 49% 21% 15% 27% 4% 6% 27% 4% 6%Sep 50% 29% 17% 27% 11% 8% 27% 11% 8%Oct 44% 14% 6% 44% 14% 6% 41% 14% 5%Nov 62% 25% 7% 62% 25% 7% 61% 25% 7%Dec 76% 42% 13% 72% 42% 12% 56% 36% 9%
All Months 71% 41% 18% 59% 34% 14% 52% 31% 12%
High Pulse Small Flood Large Flood
NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
Authorization33% 37% 14% 33% 2% 0% 22% 0% 0%
DRAFT
Appendix D 5
Figure 1 Simulated daily and monthly flows as compared to initial building blocks base flow – average target.
In this example, the WAM predicts a regulated monthly volume of 22,404 ACFT or approximately 377 cfs daily
average flow. The base average target for August is 330 cfs, so according to the monthly WAM analysis this target
would be met, however when an appropriate daily distribution is applied to this monthly flow (as described above)
half of the days fail to meet the target flow.
Unlike the monthly WAM analysis, the daily analysis allows for some interpretation of the effect of the regulated
flow on satisfying short duration high flow events. The results presented at the bottom of Table 3 represent the
annual frequency of meeting the high flow components defined in the building blocks. Thus, for instance, the 33%
for the high flow pulse target under naturalized flows means that in 33% of the years there were at least four
events for which flows exceeded 1,500 cfs for at least 2 days. The regulated simulation predicts that the high flow
pulse targets are only met in 14% of the years under the fully authorized simulation.
Conclusions
This analysis suggests three principle findings. First, the options for desired frequencies at which flow conditions
(dry, average and wet) are applicable will need to be considered if not defined. Second, in general, it appears that
base flow targets could be met at a reasonable frequency at Little and Black Cypress even assuming the fully
permitted conditions. Therefore, a reservation, which limits future diversions to protect flows in the building
blocks (assuming an appropriate trigger method to determine dry, average and wet conditions can be developed),
might be adequate to meet the objectives of this project. Finally, in Big Cypress it appears that existing permits, as
they are analyzed in the WAM, could result in lower frequencies of meeting the target conditions than might be
desired. A more detailed daily reservoir operations model will likely be necessary to evaluate the potential of
various alternatives that could be used to increase the frequency of meeting these targets.
Simulated Daily Flows for Big Cypress in August 1948
0
100
200
300
400
500
600
700
800
900
1000
4/1/1948 4/6/1948 4/11/1948 4/16/1948 4/21/1948 4/26/1948
Date
Flo
w (
cfs) Daily
Monthly Average
Target
DRAFT
Appendix D 6
Appendix D1
Monthly analysis for Naturalized Flows, Current Conditions (TCEQ‐Run8), and Full Authorization (TCEQ‐Run3) for
Little and Black Cypress Creeks.
Table 4 Monthly frequency of meeting initial building blocks target flows in Little Cypress.
Table 5 Monthly frequency of meeting initial building blocks target flows in Black Cypress.
Base Flow Targets Percent ExcedenceDry Average Wet
NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
AuthorizationJan 88% 88% 86% 75% 75% 71% 51% 51% 47%Feb 86% 86% 86% 82% 82% 76% 67% 67% 65%Mar 88% 88% 88% 75% 75% 75% 75% 75% 75%Apr 90% 90% 90% 84% 84% 82% 63% 63% 63%May 90% 90% 90% 86% 86% 84% 75% 75% 75%Jun 86% 86% 84% 73% 71% 71% 51% 51% 51%Jul 80% 80% 76% 69% 71% 67% 39% 37% 37%
Aug 65% 67% 59% 55% 57% 55% 41% 41% 41%Sep 65% 67% 63% 57% 57% 57% 39% 39% 37%Oct 75% 76% 75% 57% 57% 57% 43% 41% 41%Nov 86% 86% 86% 65% 65% 65% 43% 41% 39%Dec 88% 84% 84% 73% 73% 73% 55% 55% 53%
All Months 82% 83% 81% 71% 71% 69% 53% 53% 52%
Base Flow Targets Percent ExcedenceDry Average Wet
NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
AuthorizationJan 84% 84% 84% 69% 69% 69% 57% 57% 57%Feb 84% 84% 84% 78% 78% 78% 75% 75% 75%Mar 76% 76% 76% 75% 75% 75% 71% 71% 71%Apr 90% 90% 90% 78% 78% 78% 59% 59% 59%May 90% 90% 90% 76% 76% 76% 76% 76% 76%Jun 82% 82% 82% 63% 63% 63% 49% 49% 49%Jul 75% 75% 75% 55% 55% 55% 37% 37% 37%
Aug 61% 61% 61% 59% 59% 59% 45% 45% 45%Sep 67% 67% 67% 67% 67% 67% 35% 35% 35%Oct 75% 75% 75% 59% 59% 59% 37% 37% 37%Nov 82% 82% 82% 55% 55% 55% 35% 35% 35%Dec 76% 76% 76% 57% 57% 57% 43% 43% 43%
All Months 79% 79% 79% 66% 66% 66% 52% 52% 52%
DRAFT
Appendix D 7
Appendix D2
Daily analysis for Naturalized Flows, Current Conditions (TCEQ‐Run8), and Full Authorization (TCEQ‐Run3) for Little
and Black Cypress Creeks.
Table 6 Daily frequency of meeting initial building blocks target flows in Little Cypress.
Table 7 Daily frequency of meeting initial building blocks target flows in Black Cypress.
Base Flow Targets Percent ExcedenceDry Average Wet
NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
AuthorizationJan 84% 83% 83% 68% 68% 66% 49% 48% 47%Feb 87% 86% 85% 73% 73% 71% 60% 60% 57%Mar 88% 87% 86% 73% 73% 72% 64% 64% 63%Apr 86% 85% 85% 70% 70% 69% 57% 57% 56%May 87% 87% 86% 75% 75% 74% 61% 61% 60%Jun 78% 77% 76% 60% 59% 58% 45% 44% 43%Jul 69% 70% 68% 54% 54% 52% 34% 34% 33%
Aug 57% 61% 56% 48% 50% 47% 27% 27% 26%Sep 56% 58% 56% 49% 50% 48% 29% 28% 28%Oct 65% 67% 65% 48% 48% 46% 32% 32% 31%Nov 79% 79% 78% 58% 58% 56% 41% 40% 39%Dec 82% 81% 80% 68% 68% 66% 52% 52% 51%
All Months 76% 77% 75% 62% 62% 60% 46% 45% 44%
High Pulse Sm Flood Lg Flood
NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
Authorization39% 39% 37% 35% 35% 35% 16% 16% 16%
Base Flow Targets Percent ExcedenceDry Average Wet
NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
AuthorizationJan 79% 79% 79% 60% 60% 60% 51% 51% 51%Feb 81% 81% 81% 69% 69% 69% 61% 61% 61%Mar 76% 76% 76% 68% 68% 68% 57% 57% 57%Apr 82% 82% 82% 71% 71% 71% 51% 51% 51%May 82% 82% 82% 69% 69% 69% 60% 60% 60%Jun 70% 70% 70% 53% 53% 53% 35% 35% 35%Jul 65% 65% 64% 44% 44% 44% 30% 30% 30%
Aug 56% 56% 55% 52% 52% 52% 36% 36% 36%Sep 52% 52% 52% 52% 52% 52% 30% 30% 30%Oct 62% 62% 62% 49% 49% 49% 30% 30% 30%Nov 73% 73% 73% 49% 49% 49% 34% 34% 34%Dec 75% 75% 75% 51% 51% 51% 41% 41% 41%
All Months 71% 71% 71% 57% 57% 57% 43% 43% 43%
High Pulse Sm Flood Lg Flood
NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
Authorization NaturalizedCurrent
ConditionsFull
Authorization39% 39% 39% 35% 35% 35% 8% 8% 8%
DRAFT
Appendix D 8
Appendix D3
Analysis of gage flows for Big Cypress
Although gage records are not directly used for water availability analysis, since they do not necessarily include
existing water rights commitments, a review of pre‐ and post LOP gage records and their comparison to the initial
building blocks may be insightful. Pre‐LOP has a period of record from 1924‐1959 and post‐LOP is from 1980‐2005.
Table 8 Monthly frequency of meeting initial building blocks target flows on Big Cypress based on gage data.
Table 9 Daily frequency of meeting initial building blocks target flows on Big Cypress based on gage data.
Base Flow Targets Percent ExcedenceDry Average Wet
Pre Post Pre Post Pre PostJan 91% 78% 60% 59% 40% 37%Feb 97% 81% 51% 59% 40% 52%Mar 80% 78% 69% 59% 46% 52%Apr 83% 59% 69% 44% 43% 37%May 89% 52% 86% 52% 69% 44%Jun 66% 63% 66% 56% 51% 44%Jul 74% 89% 60% 52% 40% 37%
Aug 64% 100% 22% 8% 19% 8%Sep 61% 96% 17% 27% 17% 27%Oct 25% 52% 25% 52% 25% 52%Nov 33% 48% 33% 48% 33% 48%Dec 64% 67% 58% 67% 33% 56%
All Months 69% 79% 51% 61% 38% 56%
Base Flow Targets Percent ExcedenceDry Average Wet
Pre Post Pre Post Pre PostJan 93% 69% 71% 62% 60% 55%Feb 99% 85% 77% 76% 62% 66%Mar 86% 79% 75% 73% 65% 65%Apr 85% 68% 76% 60% 69% 53%May 91% 57% 84% 52% 69% 44%Jun 82% 81% 67% 64% 50% 54%Jul 80% 97% 55% 64% 41% 46%
Aug 70% 100% 28% 54% 28% 52%Sep 53% 89% 24% 57% 23% 53%Oct 28% 56% 28% 56% 25% 46%Nov 44% 49% 43% 48% 35% 41%Dec 74% 66% 60% 61% 44% 57%
All Months 74% 75% 57% 60% 47% 53%
High Pulse Small Flood Large FloodPre Post Pre Post Pre Post44% 35% 44% 0% 31% 0%
DRAFT
Appendix E 1
APPENDIX E IMPLEMENTATION EXAMPLE {A draft of this document entitled Draft Discussion Paper on Triggers for Flows was provided at the third flows
workshop in December 2008}
The CFP has developed the first steps for an SB3 type of flow reservation. These recommendations provide the
critical flow components for the flow regime including natural variation. This variation is captured by including the
full flow regime with associated seasonal variability and by recognizing the need for intra‐annual variability to
account for dry, average or wet water conditions. One of the challenges to the implementation of these
recommendations is the need to identify the current water condition (i.e. dry, average or wet) and develop triggers
to ensure that flow recommendations associated with the water conditions are met at desired frequencies. The
question of desired frequency was introduced and briefly discussed in Appendix D, which addressed the issue of
determining attainment frequency of the various flow recommendations. Assuming that desired frequency can be
determined, this appendix presents some first steps and ideas that will need to be considered in order to
implement a management approach on a regulated system to achieve the goals of the recommendations.
Accompanying this paper is a spreadsheet model that will be used to explain and examine some of the issues
discussed below. Please note that this is a highly idealized exercise, intended to stimulate discussion and is not
meant to serve as the basis for a final recommendation or as a replacement for a more detailed and thorough
analysis.
What parameter will be used to determine whether the conditions are Dry, Average or Wet?
One of the first issues that will need to be address is the selection of an appropriate parameter or parameters that
could be used to define dry, average or wet conditions. At least three candidates seem worth consideration.
These are meteorology (temperature, precipitation or some combination), flow and reservoir storage. From an
ecological perspective, natural inflow to Lake O’ the Pines would be an ideal choice, however since there are
reservoirs and diversions upstream, estimating naturalized inflows may prove difficult. Theoretically, inflows could
be adjusted to account for diversions and evaporations and removal of upstream return flows; other alternatives
might include rainfall or a rainfall‐runoff model. From a reservoir operations perspective the simplest trigger
would be to use reservoir levels, though these have problems; if for instance reservoirs are lowered in the future
to supply demands out of basin but in reality flow conditions in the basin are about average, we might end up
managing for dry conditions when we are actually in an average period. Ultimately the choice of an indicator is
perhaps less important than that the indicator can be used to set triggers which maintain the ecological objectives
defined in the building blocks. (‐ the important thing is that if we decide we need dry conditions exceeded 80 % of
the time then a trigger level that occurs about 80 percent of the time should be selected. This could be
accomplished with reservoir levels or flows. To the extent that this trigger is an actual indicator of dry, average
and wet would be best because it would keep flow more in synch with the natural system i.e. long term cycles etc.)
It is likely that a balance between both reservoir elevations and inflows will guide this decision. For the purposes of
developing a simple example, we chose the flow at the nearby, less impacted gage on Black Cypress as a surrogate
for water conditions in Big Cypress.
What time frame will be used to determine the current water conditions?
The next important question that needs to be addressed is the temporal window that will be used to define the
conditions. Again, there are three main possibilities. These are past, current or future (forecasted) conditions.
With perfect knowledge forecasted approach would be ideal though in the real world may not be feasible. Current
conditions may also be difficult to implement in that it might result in constantly switching from dry, average and
DRAFT
Appendix E 2
wet on a daily basis. We used the cumulative inflow for the previous three months to determine whether we are
in a dry, average or wet period. The previous three‐month inflow for each month was calculated for the Black
Cypress gage for the period of record. This data is used to select trigger flows corresponding to the frequency at
which the various water conditions should be met.
At what frequencies should the various water conditions targets be met?
As discussed in the Water Availability paper, selection of these frequencies requires some additional consideration.
For this example, the hydrograph was divided into three equal parts, with wet being those times when upstream
inflows were greater than the 33rd percentile flow, average when greater than the 66th percentile flows and dry the
rest of the time. Since flows show a strong seasonal component, these percentiles where calculated on a monthly
basis. Table 10 shows the 33rd and 66th percentile three‐month antecedent flows for Black Cypress Bayou at
Jefferson gage records.
Table 10 Black Cypress Bayou at Jefferson 33rd and 66th percentile three month antecedent flows (ACFT/3 Months).
The approach proposed in this example is that on the first day of each month the cumulative inflow for the
previous three months is calculated. If the value is less than the 33rd percentile flow, the dry targets should be in
force for the month. If the value is between the 33rd and 66th percentile flows, the average should be in force.
When the flows are greater than the 66th percentile flows, the wet targets should be in force.
How does this help to develop an implementation strategy?
Evaluation of this approach will require analysis of impacts on reservoir storage of meeting constant base flow
targets and on the potential to utilize flood storage to capture and redistribute high flows as prescribed in the flow
recommendations. This detailed analysis has not yet been performed; however, as a preliminary analysis, historic
flow records were reviewed. The example considers potential releases from Lake O’ the Pines (LOP) for 1996‐1998.
Based on annual flows 1996 was a dry year, 1997 was wet and 1998 was average. Figure 2 shows flows at Big and
Black Cypress gages.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0.33 23,063 47,528 73,835 84,525 80,629 69,311 46,943 34,319 10,609 4,067 1,792 5,4740.66 57,828 89,388 124,636 133,535 117,334 114,681 92,753 63,791 31,518 12,307 10,748 27,168
DRAFT
Appendix E 3
Figure 2 Daily flows at Big and Black Cypress gages 1996‐1998
Based on the 3 month antecedent flow the water conditions for each month is designated. Figure 3 shows the
gage flows (now just Black Cypress) on the left side y‐axis and a code for water condition (dry, average and wet) on
the right side axis.
0100020003000400050006000700080009000
10000
Jan
-96
Ap
r-9
6
Jul-
96
Oct
-96
Jan
-97
Ap
r-9
7
Jul-
97
Oct
-97
Jan
-98
Ap
r-9
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Jul-
98
Oct
-98
Flo
w (c
fs)
Date
Big
Black
DRAFT
Appendix E 4
Figure 3 Daily flows at Black Cypress gage and designated water condition.
Conditions were dry for most of 1996, wet for 1997 and variable in 1998. Based on the water conditions the
desired base flow targets can be set for Big Cypress. Figure 4 shows the base flow targets as well as the Big Cypress
historical gage flows (what was actually released from LOP)
-1
0
1
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-3000
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7000
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11000
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ter
Co
nd
ito
n
Flo
w (c
fs)
Black
Condition
Wet
Avg
Dry
DRAFT
Appendix E 5
Figure 4 Daily flows at Big Cypress gage, designated water condition, recommended release.
Figure 5 shows the same information as Figure 3 but focuses on the low flow (<500 cfs) part of the hydrograph.
-1
0
1
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4000
Jan
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ter
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nd
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Date
Big
EcoQ
Condition
Wet
Avg
Dry
DRAFT
Appendix E 6
Figure 5 Daily flows at Big Cypress gage, designated water condition, recommended release (flows < 500 cfs only)
From Figure 5 we see that during the dry 1996 year, the base flow prescriptions recommend flows that are higher
than what was historically released. During the wet 1997 year, even the wet period targets were generally
exceeded. Finally, in 1998 targets flows are reasonable close to what was released.
The next step is to include some of the high flow recommendations. Since current constraints on releases limit the
maximum flow to 3,000 cfs, we modified, for this exercise only, the building blocks recommendations. For this
exercise, average conditions will include four high flow pulses of 1,500 cfs and wet conditions will include three
high flow pulses of 1,500 cfs and one of 3,000 cfs. We also include the concept of an amount of storage that could
be used to satisfy the flow prescriptions. We have assumed that 40,000 ACFT could be available for meet the
targets on the first day of the exercise (January 1, 1996). This value will go up or down based on the difference
between the prescribed release and the actual historical release but will never exceed 40,000 ACFT.
Based on the designated water condition and the seasonal timing for high flows the first time that a high flow
release would be required would be in December 1997. December is designated wet based on antecedent flow so
on a 3,000 cfs release would be initiated. In a similar manor, three additional high flow pulses would be made in
the spring of 1997 based on water condition and the availability of storage. In December 1997, water conditions
are designated as average therefore only the 1,500 cfs release is prescribed. By February 1998, conditions are wet
and a 3,000 cfs is made. Figure 6 show the results of this exercise in terms of a prescribed release pattern (EcoQ).
050
100150200250300350400450500
Jan
-96
Ap
r-96
Jul-
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Big
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DRAFT
Appendix E 7
Figure 6 Daily flows at Big Cypress gage, designated water condition, and recommended release including pulse releases.
At the completion of this exercise, the simulated 40,000 of storage would have fallen to its minimum of 9,350 ACFT
on May 31, 1996, suggesting storage of closer to 30,000 ACFT would satisfy most of the prescribed release
requirements during low flow periods. For most of the time, less water would have been prescribed than was
historically released. Clearly, the flood events in the spring 1997 would need to be evacuated from the flood pool
and maintenance of the recommended environmental flows would be a secondary concern during this period.
Storage of 30,000‐40,000 that may be necessary to maintain flows during dry periods represents about two feet at
LOP at top of conservation pool.
-1
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EcoQ
Condition
PulseConditionWet
Avg
Dry
DRAFT
Appendix F 1
APPENDIX F NARRATIVE STANDARDS {This document was produced after the third flows workshop in December 2008. While it has been review by
several workgroup members, it has not been approved by the full Cypress Flow Workgroup. As such it is only
intended as an example that may be useful in investigating how narrative standards developed for Black and Little
Cypress may be implemented in the state's water availability and permitting framework.}
This appendix introduces an approach for the transition from an environmental flow regime (Building Blocks) to
environmental standards for the unregulated streams in the Cypress basin. The consensus at the third Cypress
Flow Project meeting (December 2008) was that the regimes developed for Black and Little Cypress did not fully
capture the goals of protecting the ecological health of Caddo Lake and its associated wetlands. Furthermore, the
transition from a regime to a standard in the Big Cypress required the recognition that, at least for the near future,
high flow flooding events could not be provided from Big Cypress given the practical limitations on releases from
Lake O’ the Pines. The workgroup did not explicitly define how the narrative standards might be implemented,
however the goal of the standards for the tributaries was to maintain the natural high flow events from this
system. Furthermore, given that Black Cypress represents a least impacted stream for the region, a rather
conservative, “hands off” approach to development in this drainage should be pursued. This paper proposes some
options for turning these concepts into a practical implementation.
Much of what follows builds on ideas presented in appendix E on the development of triggers for determining
what are wet, average and dry conditions and will not be repeated here. For the regulated Big Cypress system,
one of the important questions was how releases can be modified to meet the standards and specifically how
much water might be needed to meet these goals. For the unregulated tributaries, the question becomes how to
regulate future diversions to maintain these relatively more natural flow regimes into the future. There are several
options that might be considered including the idea of limiting diversions to a percentage of streamflow (this is
similar to the approach used in Florida), however for the purposes of these examples we have chosen to employ a
maximum diversion rate as simpler option and one that is already commonly employed in Texas water rights. The
challenge is to select a value for this maximum diversion rate. As there are still some knowledge gaps on these
tributaries, the options proposed below present a range of values to evaluate the tradeoffs between maintaining
ecological health versus the need for out of stream water supply. This discussion is intended to address the flow
standards and as such is not strictly limited to the science to determine ecological health. Finally, as there was
clearly a difference in the level of protection of instream flows that is desired for Black and Little Cypress, the
options for meeting the goals of each of these systems is presented separately. Options for the other ungaged
inflow to Caddo Lake are not specifically discussed but it is assumed that some combination of the approaches for
Black and Little Cypress Creeks, after appropriate scaling, could be developed for those tributaries.
Black Cypress
After some discussion of the high stakeholder value assigned to this system, which will not be repeated here, the
consensus of the group was that a conservative, “hands off” approach should be taken to protect flows in Black
Cypress. Generally, the group wanted to allow for very limited alteration to this regionally least disturbed stream.
A simple approach to meeting these goals would be to limit diversions to some maximum amount. While a percent
of streamflow approach, similar to the approach used in Florida, could be used to meet this objective, this
approach has not been routinely used in Texas. A more common option, which is easily implemented in the states
water availability model (WAM), is to set a maximum diversion rate. To ensure that diversions do not dewater the
stream, we also propose that the building blocks be used as a floor below which no water would be available for
diversion. The challenge is to select the actual rate to be used. It is perhaps instructive to consider some bounds.
DRAFT
Appendix F 2
If the maximum diversion rate is set equal to zero then the resulting flows for Black Cypress are identical to their
historic condition and there is no water available for future diversions. If the maximum diversion rate is set at a
very high level, say 2,000 cfs the resulting flows in Black Cypress would essentially equal the minimum of the
building blocks recommendations or the historic flow. Figure 7 and Table 11 depict the streamflow and water
availability1 for the 2,000 cfs maximum diversion scenario. (Setting a rate higher than about 2,000 cfs would have
very little impact on either streamflow or water availability, as these events are infrequent. It is unlikely that
projects for water supply would be sized for these types of events.)
Figure 7 Hydrograph for maximum diversion equal to 2,000 cfs
The 2,000 cfs scenario depicted above represents the fairly strict interpretation of the building blocks which the
group felt was not sufficiently protective of this system. The goal of the analysis presented in this document is to
determine a maximum diversion rate that balances protection of the flow regime with the ability to supply some
out of stream water demands. Clearly, this determination will require exchange between objective analysis and
subjective values.
1 These and following simulations are based on outputs from the TCEQ WAM Run 3, which includes full utilization of existing permits.
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DRAFT
Appendix F 3
Table 11 Water Availability for maximum diversion equal to 2,000 cfs
1 2 3 4 5 6 7 8 9 10 11 12 Annual1948 23,247 54,248 43,408 3,404 40,599 109 339 0 0 0 1,281 0 166,6361949 10,089 19,501 16,540 23,911 19,948 1 9,775 6,099 4,213 30,959 23,139 218 164,3931950 48,500 52,620 4,973 1,567 70,021 11,152 2,175 5,710 29,650 3,523 0 0 229,8921951 7,080 29,694 14,887 11,469 14,907 563 31 14 4,582 27 91 4 83,3511952 3,575 4,836 8,341 40,575 16,359 13,599 0 54 0 0 259 3,076 90,6741953 10,964 9,610 28,116 11,571 78,620 920 4,709 3,175 2,239 0 1,114 10,164 161,2021954 15,981 8,023 288 4,649 23,504 10,027 0 0 0 0 2,645 806 65,9231955 2,086 14,378 36,452 35,876 1,362 58 854 5,347 2,783 1,278 0 0 100,4731956 146 15,558 0 10 18,697 0 0 0 0 0 0 0 34,4121957 0 0 2,200 37,719 64,828 59,779 1,912 138 345 22,092 70,040 15,723 274,7761958 41,126 7,586 10,810 29,621 52,380 9,086 17,482 1,627 5,334 4,711 0 0 179,7631959 933 19,437 20,234 52,593 28,047 15,167 3,520 2,772 50 501 89 13,599 156,9421960 38,996 14,730 35,479 0 59 585 1,504 31 812 4,039 4,384 61,829 162,4491961 34,917 29,293 35,839 33,376 59 5,701 22,867 1,617 2,761 2,143 8,238 43,894 220,7061962 22,956 20,640 31,536 8,878 19,262 850 1,190 212 1,348 2,585 1,270 14 110,7421963 1,716 0 0 5,395 31,921 88 0 0 0 0 0 0 39,1201964 0 0 0 1,509 3,117 0 0 387 686 829 0 2,222 8,7501965 5,904 23,764 9,767 8,177 19,021 19,398 637 0 58 0 0 0 86,7271966 0 0 0 27,810 44,736 0 0 73 965 430 0 87 74,1011967 117 0 0 3,407 15,596 37,648 651 0 0 0 2 1,097 58,5151968 18,376 4,831 15,580 24,539 74,607 3,461 4,312 660 4,144 599 4,000 16,611 171,7211969 2,573 30,119 48,062 55,428 22,714 1,301 0 0 0 0 7,194 3,959 171,3511970 23,322 8,255 35,117 16,135 14,999 10,055 618 207 77 663 3,361 0 112,8081971 72 633 871 780 2,474 0 40 4,415 253 84 294 11,244 21,1601972 24,768 2,228 39 1,521 2,853 0 59 2 444 1,953 14,541 19,057 67,4641973 14,466 16,523 53,427 67,713 13,383 26,548 1,648 313 8,828 22,801 29,800 52,928 308,3781974 29,515 13,011 926 26,963 5,973 39,325 0 973 33,450 12,799 61,246 32,369 256,5501975 14,141 46,514 34,200 7,549 58,373 12,035 2,839 998 482 83 20 740 177,9741976 12,290 6,433 33,262 3,588 7,708 3,456 7,839 103 878 294 0 11,342 87,1931977 7,382 36,857 30,852 49,990 967 168 0 249 188 0 4,830 7,014 138,4981978 16,021 14,455 21,323 2,423 22,146 839 0 0 0 0 744 3,045 80,9961979 40,431 10,854 33,251 54,192 30,993 21,846 3,964 34,336 7,882 1,863 7,702 11,769 259,0831980 35,708 21,939 10,748 36,323 22,832 487 0 0 11 715 3,268 1,187 133,2201981 129 0 1,842 1,724 35,374 38,884 1,006 13 2 10,238 915 0 90,1271982 1,510 12,140 1,968 7,349 15,154 14,940 4,031 1,351 0 0 1,993 56,340 116,7751983 8,914 38,839 11,858 7,717 13,982 2,050 6,863 684 0 0 311 5,402 96,6201984 1,826 11,800 16,145 9,314 350 0 0 43 0 11,273 9,895 9,331 69,9771985 6,311 7,524 17,684 22,244 26,690 1,546 317 112 0 916 8,547 33,159 125,0501986 0 17,347 0 11,338 20,386 28,413 12,867 0 0 610 10,910 42,784 144,6561987 9,616 19,451 39,341 93 70 785 2,296 100 109 459 24,908 67,468 164,6941988 23,948 17,928 18,338 14,920 0 0 637 4 0 338 7,616 17,721 101,4501989 15,007 29,052 24,538 23,699 42,308 24,079 15,722 3,915 173 0 0 617 179,1111990 23,332 24,390 51,088 41,320 21,363 7,242 0 996 1,130 5,228 19,450 15,828 211,3661991 58,304 29,688 16,571 42,025 71,283 14,635 362 2,182 9,112 507 28,820 43,751 317,2401992 11,138 44,295 39,228 666 4,421 13,876 28,726 8,469 8,852 730 14,993 41,107 216,5021993 46,454 6,869 29,494 7,299 4,281 12,666 1,484 1,477 346 18,118 6,075 1,331 135,8941994 5,897 15,403 28,317 5,171 15,855 21,053 21,458 968 68 23,258 33,907 44,547 215,9021995 63,341 14,819 11,362 27,113 30,844 258 1,252 0 336 4 19 304 149,6511996 90 0 0 2,509 930 5,285 884 4,933 11,287 18,642 15,099 22,393 82,0511997 14,925 36,730 46,353 15,017 27,791 22,990 4,647 565 0 1,232 3,530 8,800 182,5811998 31,934 31,175 33,066 11,063 455 0 0 0 11,398 21,833 9,524 22,506 172,956
Min 0 0 0 0 0 0 0 0 0 0 0 0 8,750Ave 16,276 17,530 19,681 18,416 23,031 10,058 3,755 1,869 3,045 4,478 8,746 14,851 141,736Max 63,341 54,248 53,427 67,713 78,620 59,779 28,726 34,336 33,450 30,959 70,040 67,468 317,24075/75 115,947
DRAFT
Appendix F 4
The objective part of this analysis will proceed in three steps.
Propose metrics that will be used to evaluate impacts
Calculate metrics for a range of options including the current default methodology used in Texas water
rights permitting
Determine an alternative to the default method, as proposed herein a maximum diversion rate that
meets the objective of balancing instream flow protections and desired supply for out of stream uses.
First step is to propose the metrics, or measures of performance, to assess alternatives. The proposed metrics fall
into two categories; water availability and instream flow alteration. Within the Texas regulatory system, there are
two common measure of water availability. One is the firm yield of the system, which is how much water may be
diverted with 100% percent reliability. This value is defined by the drought of record. Firm yield is often calculated
for projects for which there is associated storage however, this analysis requires specifics related to pumping rates
and reservoir capacities. The TCEQ also sometimes determines availability based on the so‐called 75/75 rule,
which is the amount of water 75% of which is available 75% of the time. This less restrictive standard is used in
cases in which water might be used on an interruptible basis or when alternative sources such as groundwater or
storage surface water may be available for backup. The second type of metric has to do with the remaining
instream flows. Development of this metric is more subjective and illustrates the difficulty of attempting to define
a narrative standard within the inherently quantitative setting of water rights permitting. Part of the evaluation
will be accomplished based on a visual inspection of the hydrographs predicted based on the range of maximum
diversions applied. To make this analysis quantitative, the frequencies of exceeding a range of flows will also be
calculated and compared relative the frequencies expected under the WAM fully permitted scenario.
Water availability results are presented in Table 12 suggest that maximum diversion rate has little effect on firm
yield until the rate drops below about 250 cfs. Clearly the sensitivity to changes in the maximum diversion rate are
greater for the 75/75 yield, exactly what this means in terms of water supply would require more specific
information and a more detailed analysis.
Table 12 Water Availability Summary for maximum diversion equal to 50 to 2,000 cfs
Figure 8 ‐ Figure 11 present predicted hydrographs for maximum diversion rates of 50, 100, 250 and 500 cfs
simulated for 1996‐1998 (selected simply because these years include dry, wet and average conditions). While the
impact on streamflow might be evaluated more quantifiably by the statistics presented in Table 13, visual
interpretation of Figure 8 ‐ Figure 11 may be just as informative. For instance, while it may be difficult to precisely
quantify the ecological value of providing the approximately 800 cfs in channel pulses in winter 1996‐97 under the
100 cfs option versus not providing them under the 500 cfs maximum diversion option, this is the type of natural
variability that the group wishes to maintain which would not be maintained were we to implement a more strict
interpretation of the building blocks. What the graphs and tables show is that higher maximum diversion rates
mean more water availability while lower maximum diversion rates provide flows more similar to their natural
pattern.
Yield Max50 Max100 Max250 Max500 Max2000Min 4,034 5,974 8,689 8,750 8,750Avg 17,458 31,445 62,554 93,842 141,736Max 28,051 53,282 115,839 182,314 317,24075/75 20,059 35,408 67,754 92,398 115,947
DRAFT
Appendix F 5
Figure 8 Hydrograph for maximum diversion equal to 50 cfs
Figure 9 Hydrograph for maximum diversion equal to 100 cfs
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Appendix F 6
Figure 10 Hydrograph for maximum diversion equal to 250 cfs
Figure 11 Hydrograph for maximum diversion equal to 500 cfs
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Appendix F 7
Table 13 and Table 14 summarize historical frequencies of meeting a range of flows.
Table 13 Frequency of meeting or exceeding a range of low rates under alternative scenarios
Table 14 Percent decrease, relative to WAM Run3, of meeting or exceeding a range of low rates under alternative scenarios
Table 14 shows that a maximum diversion rate of 50 cfs would result in about a 10% decrease in meeting mid
range flows (250‐1,000 cfs) and about a 5% decrease in meeting higher flows (1,000‐6,000 cfs). These percentages
about double when the maximum diversion rate is increased to 100 cfs and double again at a maximum diversion
of 250 cfs. When the maximum diversion rate is greater than 500 cfs the mid range flows are meet only about half
as often as the fully permitted WAM scenario and the higher flows 20‐30% less often.
The second step in this evaluation is to determine the yield that would be available under the current default
methodology used by TCEQ in evaluating the water rights permits. This method, called the Lyons method, sets
minimum flow targets based on a percent of the historical monthly medians (60% in the summer and 40 % in the
winter months). Table 15 shows the Lyons target alongside the building blocks (low flow targets) for Black Cypress.
The Lyons method does not afford and protection other portions of the hydrograph beyond low flows.
Flow WAM (Run3) Max50 Max100 Max250 Max500 Max2000250 7,017 6,427 5,967 4,869 3,905 3,208500 3,939 3,535 3,074 2,203 1,397 641600 3,074 2,739 2,474 1,786 1,214 572700 2,474 2,203 1,949 1,511 1,041 492800 1,949 1,786 1,652 1,300 874 434900 1,652 1,511 1,397 1,115 749 3881000 1,397 1,300 1,214 966 641 3512000 351 338 320 285 246 1923000 160 153 148 129 111 934000 93 92 88 83 76 615000 61 60 60 56 50 446000 44 42 41 39 35 287000 28 28 26 26 21 218000 21 21 21 21 17 119000 11 11 11 11 11 1110000 11 11 11 11 10 6
Flow WAM (Run3) Max50 Max100 Max250 Max500 Max2000250 - 8% 15% 31% 44% 54%500 - 10% 22% 44% 65% 84%600 - 11% 20% 42% 61% 81%700 - 11% 21% 39% 58% 80%800 - 8% 15% 33% 55% 78%900 - 9% 15% 33% 55% 77%1000 - 7% 13% 31% 54% 75%2000 - 4% 9% 19% 30% 45%3000 - 4% 8% 19% 31% 42%4000 - 1% 5% 11% 18% 34%5000 - 2% 2% 8% 18% 28%6000 - 5% 7% 11% 20% 36%7000 - 0% 7% 7% 25% 25%8000 - 0% 0% 0% 19% 48%9000 - 0% 0% 0% 0% 0%10000 0% 0% 0% 9% 45%
DRAFT
Appendix F 8
Table 15 Low flow targets (Lyons and Building Blocks)
Using the same approach applied above, the firm yield that would be expected assuming the TCEQ’s default
methodology would be 6,898 ACFT per year. Through trial and error iteration it was determined that this same
firm yield would be expected based on application of the building blocks targets with a maximum diversion rate of
129 cfs.
Table 16 ‐ Table 18 below repeat the results provided above but include the simulations for Lyons and the
maximum diversion rate of 129 cfs.
Table 16 Water Availability Summary for maximum diversion equal to 50 to 2,000 cfs and Lyons
Table 17 Frequency of meeting or exceeding a range of low rates under alternative scenarios including Lyons
Month Lyons Dry Avg WetJan 142 125 222 322Feb 190 201 300 366Mar 296 242 306 382Apr 188 140 205 327May 134 80 156 210Jun 78 42 95 191Jul 17 11 32 63Aug 3 4 5 14Sep 2 4 4 19Oct 4 4 13 45Nov 43 19 74 158Dec 114 91 209 294
Building Blocks Low Flow Targets
Yield Max50 Max100 Max129 Max250 Max500 Max2000 LyonsMin 4,034 5,974 6,816 8,689 8,750 8,750 6,898Avg 17,458 31,445 38,540 62,554 93,842 141,736 184,627Max 28,051 53,282 67,117 115,839 182,314 317,240 436,90575/75 20,059 35,408 41,493 67,754 92,398 115,947 125,773
Flow WAM (Run3) Max50 Max100 Max129 Max250 Max500 Max2000 Lyons250 7,017 6,427 5,967 5,712 4,869 3,905 3,208 1,192500 3,939 3,535 3,074 2,888 2,203 1,397 641 0600 3,074 2,739 2,474 2,314 1,786 1,214 572 0700 2,474 2,203 1,949 1,842 1,511 1,041 492 0800 1,949 1,786 1,652 1,567 1,300 874 434 0900 1,652 1,511 1,397 1,340 1,115 749 388 01000 1,397 1,300 1,214 1,168 966 641 351 02000 351 338 320 318 285 246 192 03000 160 153 148 146 129 111 93 04000 93 92 88 88 83 76 61 05000 61 60 60 59 56 50 44 06000 44 42 41 40 39 35 28 07000 28 28 26 26 26 21 21 08000 21 21 21 21 21 17 11 09000 11 11 11 11 11 11 11 010000 11 11 11 11 11 10 6 0
DRAFT
Appendix F 9
Table 18 Percent decrease, relative to WAM Run3, of meeting or exceeding a range of low rates under alternative scenarios including Lyons
Flow WAM (Run3) Max50 Max100 Max129 Max250 Max500 Max2000 Lyons250 - 8% 15% 19% 31% 44% 54% 83%500 - 10% 22% 27% 44% 65% 84% 100%600 - 11% 20% 25% 42% 61% 81% 100%700 - 11% 21% 26% 39% 58% 80% 100%800 - 8% 15% 20% 33% 55% 78% 100%900 - 9% 15% 19% 33% 55% 77% 100%1000 - 7% 13% 16% 31% 54% 75% 100%2000 - 4% 9% 9% 19% 30% 45% 100%3000 - 4% 8% 9% 19% 31% 42% 100%4000 - 1% 5% 5% 11% 18% 34% 100%5000 - 2% 2% 3% 8% 18% 28% 100%6000 - 5% 7% 9% 11% 20% 36% 100%7000 - 0% 7% 7% 7% 25% 25% 100%8000 - 0% 0% 0% 0% 19% 48% 100%9000 - 0% 0% 0% 0% 0% 0% 100%10000 0% 0% 0% 0% 9% 45% 100%
DRAFT
Appendix F 10
Little Cypress
In discussing Little Cypress, the stakeholder group recognized that this stream has experienced moderate
alterations and is being considered for future water development; however the group also recognized that
protection of high flows in this stream would be desirable given that the high flow events from Big Cypress will be
limited by releases from Lake O’ the Pines. As a result, the group felt that a hybrid approach between a strict
interpretation of the building block approach being applied to Big Cypress and the more conservative hands off
approach being proposed for Black Cypress. While the group was not specific on exactly what this means, we
interpreted the goal as meaning water below bankfull would be available for diversion subject to the constraints of
the numerical building blocks targets but flows above bankfull would be subject to greater protection via the
application of a maximum diversion rate similar to the approach described above. To state this operationally if
flows are greater than bank full water can be diverted to just above bankfull subject to limits of a maximum
diversion rate. If the flow is below bankfull, then water can be diverted down to the building block level but is not
subject to a maximum diversion rate, put another way in channel pulses that are not explicitly defined in the
building blocks can be diverted. The methodology will likely need refinements, one potential issue that might
cause concern is that fact the diversions can be greater for flow just below bankfull than higher flows just above
bankfull. The following pages present results identical to those presented above for Black Cypress.
What is particularly notable from the following figures and tables is how much less sensitive both the changes in
stream flow and changes in water availability are to changes in the maximum diversion rate. What is likely a far
more critical parameter is the estimate of bankfull flow. The bankfull estimate included in the building blocks is
represented by the 2‐year recurrence interval estimate which for Little Cypress is 2,700 cfs. The figures below
show that flows greater than bankfull are relatively unaltered regardless of maximum diversion rate. However, if
as was the case in Big Cypress, field work (planned for this year) were to conclude that bankfull is actually
considerably lower, say 1,500 cfs then many of the smaller, yet assumed to be in channel, peaks that would be
diverted if bankfull were 2,700 cfs would be protected from diversion if bankfull is actually 1,500 cfs.
DRAFT
Appendix F 11
0 cfs
Little Cypress
0
1000
2000
3000
4000
5000
6000
7000
8000
Jan
-96
Feb
-96
Mar
-96
Ap
r-96
Ma
y-9
6Ju
n-9
6J
ul-
96
Au
g-9
6S
ep
-96
Oct
-96
No
v-9
6D
ec-
96
Jan
-97
Feb
-97
Mar
-97
Ap
r-97
Ma
y-9
7Ju
n-9
7J
ul-
97
Au
g-9
7S
ep
-97
Oct
-97
No
v-9
7D
ec-
97
Jan
-98
Feb
-98
Mar
-98
Ap
r-98
Ma
y-9
8Ju
n-9
8J
ul-
98
Au
g-9
8S
ep
-98
Oct
-98
No
v-9
8D
ec-
98
Date
Flo
w (
cfs
)
0
1
2
Wat
er C
on
dit
ion
LittleRegulatedTargetBase
Little Cypress
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Jan
-96
Feb
-96
Mar
-96
Ap
r-96
Ma
y-9
6Ju
n-9
6J
ul-
96
Au
g-9
6S
ep
-96
Oct
-96
No
v-9
6D
ec-
96
Jan
-97
Feb
-97
Mar
-97
Ap
r-97
Ma
y-9
7Ju
n-9
7J
ul-
97
Au
g-9
7S
ep
-97
Oct
-97
No
v-9
7D
ec-
97
Jan
-98
Feb
-98
Mar
-98
Ap
r-98
Ma
y-9
8Ju
n-9
8J
ul-
98
Au
g-9
8S
ep
-98
Oct
-98
No
v-9
8D
ec-
98
Date
Flo
w (
cfs
)
0
1
2
Wat
er C
on
dit
ion
LittleRegulatedTargetBase
DRAFT
Appendix F 12
Max Diversion = 01 2 3 4 5 6 7 8 9 10 11 12 Annual
1969 8,781 41,933 45,392 68,384 41,500 2,067 0 0 0 0 7,206 13,916 229,1781970 31,287 7,131 52,582 20,709 24,305 1,450 2,071 121 0 1,322 5,641 506 147,1251971 296 1,168 662 561 198 0 0 2,938 231 0 538 16,253 22,8451972 48,978 4,782 4,536 468 2,015 2,515 1,353 0 159 4,282 21,900 42,579 133,5671973 23,913 35,306 42,456 29,094 22,739 49,289 1,767 389 31,980 44,087 40,885 47,514 369,4181974 65,520 27,973 12,651 29,324 17,524 26,588 127 446 50,813 18,268 77,377 78,067 404,6781975 31,099 24,968 37,196 27,598 71,952 24,409 6,175 990 397 137 290 1,470 226,6791976 15,072 9,255 42,200 6,250 17,341 4,552 36,833 1,708 1,801 1,327 369 21,064 157,7731977 19,525 38,208 65,298 52,618 9,287 460 0 7,280 6,359 801 3,249 6,780 209,8641978 14,811 19,380 32,965 6,242 13,819 220 0 26 0 0 169 1,355 88,9871979 62,154 29,131 62,267 38,701 23,383 27,503 7,012 39,148 18,436 12,619 17,314 28,330 365,9981980 36,805 55,771 10,449 57,540 52,667 1,490 0 0 0 260 1,482 403 216,8671981 0 0 879 1,442 39,665 51,300 2,440 54 442 3,898 486 3,146 103,7521982 930 14,009 8,567 4,865 16,516 3,511 2,214 20 0 0 962 53,895 105,4891983 8,303 56,761 37,367 15,384 16,600 6,252 3,368 0 0 0 254 18,609 162,8971984 1,749 24,242 24,462 12,490 549 180 99 0 0 6,231 4,086 3,606 77,6951985 4,457 4,074 29,816 34,897 45,794 7,521 107 14 0 1,633 17,439 55,303 201,0561986 621 36,633 0 15,884 19,577 26,150 2,110 0 0 60 4,885 40,677 146,5961987 2,604 23,038 63,372 2,233 803 13,208 4,407 34 0 104 14,110 55,620 179,5351988 30,980 28,901 35,457 20,777 0 0 811 5 0 276 5,657 2,749 125,6121989 12,986 47,881 14,680 24,307 32,579 33,130 17,593 3,122 63 0 175 141 186,6571990 30,938 58,443 50,983 59,338 31,617 33,295 85 1,595 3,894 6,849 44,817 50,624 372,4761991 53,153 32,549 31,186 42,847 36,000 20,057 4,475 3,150 1,866 432 14,099 66,236 306,0501992 34,723 69,733 49,176 3,455 46 14,214 40,794 2,858 4,415 1,107 25,450 35,224 281,1951993 56,793 27,372 62,543 18,010 19,337 33,346 9,142 3,396 4 14,469 13,803 900 259,1161994 3,132 14,622 36,008 15,667 32,624 4,709 28,780 670 0 37,531 39,259 32,783 245,7861995 63,741 22,068 13,757 47,141 46,568 3,215 1,732 0 379 81 666 613 199,9621996 167 0 0 720 1,139 7,531 861 5,137 19,791 18,805 11,710 38,864 104,7251997 20,007 8,463 74,822 16,078 22,064 21,126 23,673 2,743 0 3,564 3,602 23,841 219,9851998 45,896 50,582 35,937 3,572 95 180 0 56 12,194 42,938 31,650 55,654 278,7551999 26,690 15,759 22,151 24,962 25,716 27,765 13,135 10 0 0 0 1,859 158,0452000 367 1,091 8,533 47,004 66,635 7,718 20,208 0 0 0 22,096 27,019 200,6702001 42,367 31,236 25,730 22,483 8,212 29,092 2,537 303 11,905 31,932 7,133 48,129 261,0572002 9,037 11,881 10,546 38,424 1,898 0 825 1,025 2,227 2,049 1,039 24,831 103,7832003 26,914 19,000 35,459 4,840 7,160 20,928 3,941 2,521 739 74 454 192 122,2222004 4,737 36,298 49,827 7,882 39,164 73,468 23,060 472 0 1,071 14,344 19,597 269,9192005 19,561 25,775 8,910 7,341 0 0 0 0 53 0 0 0 61,6402006 40 226 34,062 4,257 885 0 0 0 0 0 0 766 40,2352007 28,629 5,064 464 4,187 17,851 23,683 54,026 27,604 1,037 0 46 5,633 168,2242008 4,860 32,400 56,253 47,706 28,009 1,392 1,652 4,863 9,832 5,441 6,976 3,719 203,103
Min 0 0 0 468 0 0 0 0 0 0 0 0 22,845Ave 22,315 24,828 30,740 22,142 21,346 15,088 7,935 2,817 4,475 6,541 11,540 23,212 192,980Max 65,520 69,733 74,822 68,384 71,952 73,468 54,026 39,148 50,813 44,087 77,377 78,067 404,678
DRAFT
Appendix F 13
500 cfs
Little Cypress
0
1000
2000
3000
4000
5000
6000
7000
8000
Jan
-96
Feb
-96
Mar
-96
Ap
r-96
Ma
y-9
6Ju
n-9
6J
ul-
96
Au
g-9
6S
ep
-96
Oct
-96
No
v-9
6D
ec-
96
Jan
-97
Feb
-97
Mar
-97
Ap
r-97
Ma
y-9
7Ju
n-9
7J
ul-
97
Au
g-9
7S
ep
-97
Oct
-97
No
v-9
7D
ec-
97
Jan
-98
Feb
-98
Mar
-98
Ap
r-98
Ma
y-9
8Ju
n-9
8J
ul-
98
Au
g-9
8S
ep
-98
Oct
-98
No
v-9
8D
ec-
98
Date
Flo
w (
cfs
)
0
1
2
Wat
er C
on
dit
ion
LittleRegulatedTargetCondition
Little Cypress
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Jan
-96
Feb
-96
Mar
-96
Ap
r-96
Ma
y-9
6Ju
n-9
6J
ul-
96
Au
g-9
6S
ep
-96
Oct
-96
No
v-9
6D
ec-
96
Jan
-97
Feb
-97
Mar
-97
Ap
r-97
Ma
y-9
7Ju
n-9
7J
ul-
97
Au
g-9
7S
ep
-97
Oct
-97
No
v-9
7D
ec-
97
Jan
-98
Feb
-98
Mar
-98
Ap
r-98
Ma
y-9
8Ju
n-9
8J
ul-
98
Au
g-9
8S
ep
-98
Oct
-98
No
v-9
8D
ec-
98
Date
Flo
w (
cfs
)
0
1
2
Wat
er C
on
dit
ion
LittleRegulatedTargetCondition
DRAFT
Appendix F 14
Max Diversion = 5001 2 3 4 5 6 7 8 9 10 11 12 Annual
1969 8,781 38,515 43,706 51,265 41,500 2,067 0 0 0 0 7,206 13,916 206,9551970 31,287 7,131 52,582 20,709 21,519 1,450 2,071 121 0 1,322 5,641 506 144,3381971 296 1,168 662 561 198 0 0 2,938 231 0 538 16,253 22,8451972 45,788 4,782 4,536 468 2,015 2,515 1,353 0 159 4,282 21,900 42,579 130,3771973 23,913 35,306 38,261 39,181 21,846 35,276 1,767 389 31,980 36,918 40,594 56,440 361,8701974 41,298 27,973 12,651 26,184 17,524 31,043 127 446 50,813 18,268 74,156 68,170 368,6521975 31,099 27,586 31,853 27,598 63,761 24,409 6,175 990 397 137 290 1,470 215,7621976 15,072 9,255 42,200 6,250 17,341 4,552 36,833 1,708 1,801 1,327 369 21,064 157,7731977 19,525 38,390 56,957 47,720 9,287 460 0 7,280 6,359 801 3,249 6,780 196,8091978 14,811 19,380 32,965 6,242 13,819 220 0 26 0 0 169 1,355 88,9871979 48,048 29,131 62,267 41,911 30,325 27,503 7,012 39,148 18,502 12,619 17,314 28,330 362,1081980 34,810 39,427 10,449 57,540 52,667 1,490 0 0 0 260 1,482 403 198,5281981 0 0 879 1,442 32,945 51,300 2,440 54 442 3,898 486 3,146 97,0321982 930 14,009 8,567 4,865 16,516 3,511 2,214 20 0 0 962 53,895 105,4891983 8,303 56,761 31,805 15,384 16,600 6,252 3,368 0 0 0 254 18,609 157,3351984 1,749 24,242 24,462 12,490 549 180 99 0 0 6,231 4,086 3,606 77,6951985 4,457 4,074 27,207 34,897 45,794 7,521 107 14 0 1,633 17,439 52,614 195,7581986 621 30,413 0 15,884 19,577 26,150 2,110 0 0 60 4,885 40,677 140,3761987 2,604 20,559 48,714 2,233 803 13,208 4,407 34 0 104 14,110 61,571 168,3481988 30,805 24,300 35,457 20,777 0 0 811 5 0 276 5,657 2,749 120,8361989 12,986 45,455 17,655 22,566 38,013 33,130 17,593 3,122 63 0 175 141 190,8991990 26,503 58,443 46,933 55,870 27,074 33,295 85 1,595 3,894 6,849 36,902 41,024 338,4671991 43,065 21,084 24,728 42,772 42,407 18,448 4,475 3,150 1,866 432 14,099 39,420 255,9451992 34,723 48,173 27,874 3,455 46 14,214 29,326 2,858 4,415 1,107 25,450 35,125 226,7641993 51,965 27,372 62,543 18,010 19,337 29,581 9,142 3,396 4 14,469 13,803 900 250,5231994 3,132 13,287 35,115 15,667 32,624 4,709 28,780 670 0 37,531 36,627 37,166 245,3101995 46,826 16,395 13,757 33,059 39,467 3,215 1,732 0 379 81 666 613 156,1901996 167 0 0 720 1,139 7,531 861 5,137 19,791 18,805 11,710 38,864 104,7251997 20,007 24,331 44,666 18,359 23,730 21,126 23,673 2,743 0 3,564 3,602 23,841 209,6431998 52,802 36,173 35,937 3,572 95 180 0 56 12,194 42,938 31,650 55,654 271,2521999 24,670 17,762 22,151 24,962 25,716 27,765 13,135 10 0 0 0 1,859 158,0292000 367 1,091 8,533 47,004 66,635 7,718 20,208 0 0 0 22,096 30,450 204,1012001 45,513 33,398 42,664 22,483 8,212 26,471 2,537 303 11,905 31,932 7,133 44,321 276,8712002 9,037 11,881 14,057 37,139 1,898 0 825 1,025 2,227 2,049 1,039 24,831 106,0092003 26,914 21,372 30,024 4,840 7,160 20,928 3,941 2,521 739 74 454 192 119,1592004 4,737 36,298 49,827 7,882 39,164 56,846 23,060 472 0 1,071 14,344 19,597 253,2972005 19,561 25,775 8,910 7,341 0 0 0 0 53 0 0 0 61,6402006 40 226 24,357 4,257 885 0 0 0 0 0 0 766 30,5302007 34,802 5,064 464 4,187 17,851 21,572 45,457 27,604 1,037 0 46 5,633 163,7182008 4,860 32,400 56,253 46,393 27,572 1,392 1,652 4,863 9,832 5,441 6,976 3,719 201,354
Min 0 0 0 468 0 0 0 0 0 0 0 0 22,845Ave 20,672 23,210 28,316 21,354 21,090 14,181 7,434 2,817 4,477 6,362 11,189 22,456 183,558Max 52,802 58,443 62,543 57,540 66,635 56,846 45,457 39,148 50,813 42,938 74,156 68,170 368,652
DRAFT
Appendix F 15
250 cfs
Little Cypress
0
1000
2000
3000
4000
5000
6000
7000
8000
Jan
-96
Feb
-96
Mar
-96
Ap
r-96
Ma
y-9
6Ju
n-9
6J
ul-
96
Au
g-9
6S
ep
-96
Oct
-96
No
v-9
6D
ec-
96
Jan
-97
Feb
-97
Mar
-97
Ap
r-97
Ma
y-9
7Ju
n-9
7J
ul-
97
Au
g-9
7S
ep
-97
Oct
-97
No
v-9
7D
ec-
97
Jan
-98
Feb
-98
Mar
-98
Ap
r-98
Ma
y-9
8Ju
n-9
8J
ul-
98
Au
g-9
8S
ep
-98
Oct
-98
No
v-9
8D
ec-
98
Date
Flo
w (
cfs
)
0
1
2
Wat
er C
on
dit
ion
LittleRegulatedTargetCondition
Little Cypress
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Jan
-96
Feb
-96
Mar
-96
Ap
r-96
Ma
y-9
6Ju
n-9
6J
ul-
96
Au
g-9
6S
ep
-96
Oct
-96
No
v-9
6D
ec-
96
Jan
-97
Feb
-97
Mar
-97
Ap
r-97
Ma
y-9
7Ju
n-9
7J
ul-
97
Au
g-9
7S
ep
-97
Oct
-97
No
v-9
7D
ec-
97
Jan
-98
Feb
-98
Mar
-98
Ap
r-98
Ma
y-9
8Ju
n-9
8J
ul-
98
Au
g-9
8S
ep
-98
Oct
-98
No
v-9
8D
ec-
98
Date
Flo
w (
cfs
)
0
1
2
Wat
er C
on
dit
ion
LittleRegulatedTargetCondition
DRAFT
Appendix F 16
Max Diversion = 2501 2 3 4 5 6 7 8 9 10 11 12 Annual
1969 8,781 38,019 40,026 59,659 41,500 2,067 0 0 0 0 7,206 13,916 211,1741970 31,287 7,131 52,582 20,709 21,003 1,450 2,071 121 0 1,322 5,641 506 143,8231971 296 1,168 662 561 198 0 0 2,938 231 0 538 16,253 22,8451972 48,978 4,782 4,536 468 2,015 2,515 1,353 0 159 4,282 21,900 42,579 133,5671973 23,913 35,306 38,410 35,540 23,730 38,533 1,767 389 31,980 35,431 42,373 51,977 359,3471974 58,427 27,973 12,651 29,324 17,524 30,555 127 446 50,813 18,268 74,924 74,021 395,0521975 31,099 28,935 33,860 27,598 72,508 24,409 6,175 990 397 137 290 1,470 227,8651976 15,072 9,255 42,200 6,250 17,341 4,552 36,833 1,708 1,801 1,327 369 21,064 157,7731977 19,525 41,679 65,298 51,362 9,287 460 0 7,280 6,359 801 3,249 6,780 212,0791978 14,811 19,380 32,965 6,242 13,819 220 0 26 0 0 169 1,355 88,9871979 57,953 29,131 62,267 41,074 26,854 27,503 7,012 39,148 16,022 12,619 17,314 28,330 365,2261980 31,339 48,928 10,449 57,540 52,667 1,490 0 0 0 260 1,482 403 204,5571981 0 0 879 1,442 39,665 51,300 2,440 54 442 3,898 486 3,146 103,7521982 930 14,009 8,567 4,865 16,516 3,511 2,214 20 0 0 962 53,895 105,4891983 8,303 56,761 30,813 15,384 16,600 6,252 3,368 0 0 0 254 18,609 156,3431984 1,749 24,242 24,462 12,490 549 180 99 0 0 6,231 4,086 3,606 77,6951985 4,457 4,074 29,816 34,897 45,794 7,521 107 14 0 1,633 17,439 51,999 197,7511986 621 32,898 0 15,884 19,577 26,150 2,110 0 0 60 4,885 40,677 142,8611987 2,604 23,038 50,221 2,233 803 13,208 4,407 34 0 104 14,110 58,596 169,3601988 28,822 28,901 35,457 20,777 0 0 811 5 0 276 5,657 2,749 123,4541989 12,986 44,840 16,167 22,673 33,055 33,130 17,593 3,122 63 0 175 141 183,9451990 28,046 58,443 48,264 53,550 28,740 33,295 85 1,595 3,894 6,849 35,911 46,677 345,3481991 40,618 22,116 25,486 42,184 40,899 16,961 4,475 3,150 1,866 432 14,099 46,461 258,7461992 34,723 55,987 42,004 3,455 46 14,214 31,912 2,858 4,415 1,107 25,450 30,662 246,8331993 55,250 27,372 62,543 18,010 19,337 30,680 9,142 3,396 4 14,469 13,803 900 254,9071994 3,132 11,899 34,709 15,667 32,624 4,709 28,780 670 0 37,531 35,635 32,842 238,1991995 56,886 15,404 13,757 30,083 38,475 3,215 1,732 0 379 81 666 613 161,2921996 167 0 0 720 1,139 7,531 861 5,137 19,791 18,805 11,710 38,864 104,7251997 20,007 16,397 58,637 17,367 20,755 21,126 23,673 2,743 0 3,564 3,602 23,841 211,7141998 50,854 46,689 35,937 3,572 95 180 0 56 12,194 42,938 31,650 55,654 279,8201999 23,679 14,787 22,151 24,962 25,716 27,765 13,135 10 0 0 0 1,859 154,0622000 367 1,091 8,533 47,004 66,635 7,718 20,208 0 0 0 22,096 28,963 202,6142001 41,264 28,439 32,251 22,483 8,212 29,587 2,537 303 11,905 31,932 7,133 48,744 264,7892002 9,037 11,881 12,530 33,667 1,898 0 825 1,025 2,227 2,049 1,039 24,831 101,0102003 26,914 17,901 35,459 4,840 7,160 20,928 3,941 2,521 739 74 454 192 121,1232004 4,737 36,298 49,827 7,882 39,164 60,920 23,060 472 0 1,071 14,344 19,597 257,3712005 19,561 25,775 8,910 7,341 0 0 0 0 53 0 0 0 61,6402006 40 226 34,062 4,257 885 0 0 0 0 0 0 766 40,2352007 29,347 5,064 464 4,187 17,851 17,605 45,667 27,604 1,037 0 46 5,633 154,5062008 4,860 32,400 56,253 48,698 27,324 1,392 1,652 4,863 9,832 5,441 6,976 3,719 203,411
Min 0 0 0 468 0 0 0 0 0 0 0 0 22,845Ave 21,286 23,715 29,352 21,423 21,199 14,321 7,504 2,817 4,415 6,325 11,203 22,572 186,132Max 58,427 58,443 65,298 59,659 72,508 60,920 45,667 39,148 50,813 42,938 74,924 74,021 395,052
DRAFT
Appendix F 17
100 cfs
Little Cypress
0
1000
2000
3000
4000
5000
6000
7000
8000
Jan
-96
Feb
-96
Mar
-96
Ap
r-96
Ma
y-9
6Ju
n-9
6J
ul-
96
Au
g-9
6S
ep
-96
Oct
-96
No
v-9
6D
ec-
96
Jan
-97
Feb
-97
Mar
-97
Ap
r-97
Ma
y-9
7Ju
n-9
7J
ul-
97
Au
g-9
7S
ep
-97
Oct
-97
No
v-9
7D
ec-
97
Jan
-98
Feb
-98
Mar
-98
Ap
r-98
Ma
y-9
8Ju
n-9
8J
ul-
98
Au
g-9
8S
ep
-98
Oct
-98
No
v-9
8D
ec-
98
Date
Flo
w (
cfs
)
0
1
2
Wat
er C
on
dit
ion
LittleRegulatedTargetCondition
Little Cypress
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Jan
-96
Feb
-96
Mar
-96
Ap
r-96
Ma
y-9
6Ju
n-9
6J
ul-
96
Au
g-9
6S
ep
-96
Oct
-96
No
v-9
6D
ec-
96
Jan
-97
Feb
-97
Mar
-97
Ap
r-97
Ma
y-9
7Ju
n-9
7J
ul-
97
Au
g-9
7S
ep
-97
Oct
-97
No
v-9
7D
ec-
97
Jan
-98
Feb
-98
Mar
-98
Ap
r-98
Ma
y-9
8Ju
n-9
8J
ul-
98
Au
g-9
8S
ep
-98
Oct
-98
No
v-9
8D
ec-
98
Date
Flo
w (
cfs
)
0
1
2
Wat
er C
on
dit
ion
LittleRegulatedTargetCondition
DRAFT
Appendix F 18
Max Diversion = 1001 2 3 4 5 6 7 8 9 10 11 12 Annual
1969 8,781 37,722 47,772 65,304 41,500 2,067 0 0 0 0 7,206 13,916 224,2671970 31,287 7,131 52,582 20,709 24,702 1,450 2,071 121 0 1,322 5,641 506 147,5221971 296 1,168 662 561 198 0 0 2,938 231 0 538 16,253 22,8451972 48,978 4,782 4,536 468 2,015 2,515 1,353 0 159 4,282 21,900 42,579 133,5671973 23,913 35,306 39,788 31,672 23,135 40,776 1,767 389 31,980 39,332 41,480 49,299 358,8381974 65,520 27,973 12,651 29,324 17,524 28,175 127 446 50,813 18,268 73,436 78,067 402,3231975 31,099 26,555 37,196 27,598 72,468 24,409 6,175 990 397 137 290 1,470 228,7811976 15,072 9,255 42,200 6,250 17,341 4,552 36,833 1,708 1,801 1,327 369 21,064 157,7731977 19,525 39,596 65,298 49,418 9,287 460 0 7,280 6,359 801 3,249 6,780 208,0531978 14,811 19,380 32,965 6,242 13,819 220 0 26 0 0 169 1,355 88,9871979 62,154 29,131 62,267 37,206 24,772 27,503 7,012 39,148 19,230 12,619 17,314 28,330 366,6841980 37,995 51,903 10,449 57,540 52,667 1,490 0 0 0 260 1,482 403 214,1891981 0 0 879 1,442 39,665 51,300 2,440 54 442 3,898 486 3,146 103,7521982 930 14,009 8,567 4,865 16,516 3,511 2,214 20 0 0 962 53,895 105,4891983 8,303 56,761 37,545 15,384 16,600 6,252 3,368 0 0 0 254 18,609 163,0751984 1,749 24,242 24,462 12,490 549 180 99 0 0 6,231 4,086 3,606 77,6951985 4,457 4,074 29,816 34,897 45,794 7,521 107 14 0 1,633 17,439 55,700 201,4521986 621 36,633 0 15,884 19,577 26,150 2,110 0 0 60 4,885 40,677 146,5961987 2,604 23,038 60,010 2,233 803 13,208 4,407 34 0 104 14,110 56,811 177,3631988 31,575 28,901 35,457 20,777 0 0 811 5 0 276 5,657 2,749 126,2071989 12,986 48,079 15,275 25,101 34,364 33,130 17,593 3,122 63 0 175 141 190,0281990 31,533 58,443 51,578 55,898 32,013 33,295 85 1,595 3,894 6,849 39,927 50,624 365,7341991 55,513 28,681 27,830 44,037 37,983 20,454 4,475 3,150 1,866 432 14,099 61,912 300,4321992 34,723 65,885 46,911 3,455 46 14,214 40,794 2,858 4,415 1,107 25,450 36,732 276,5891993 57,586 27,372 62,543 18,010 19,337 29,193 9,142 3,396 4 14,469 13,803 900 255,7561994 3,132 15,019 37,000 15,667 32,624 4,709 28,780 670 0 37,531 39,457 34,370 248,9591995 55,934 22,108 13,757 43,384 42,115 3,215 1,732 0 379 81 666 613 183,9851996 167 0 0 720 1,139 7,531 861 5,137 19,791 18,805 11,710 38,864 104,7251997 20,007 11,637 67,337 16,673 23,056 21,126 23,673 2,743 0 3,564 3,602 23,841 217,2601998 47,879 46,391 35,937 3,572 95 180 0 56 12,194 42,938 31,650 55,654 276,5471999 26,888 16,750 22,151 24,962 25,716 27,765 13,135 10 0 0 0 1,859 159,2352000 367 1,091 8,533 47,004 66,635 7,718 20,208 0 0 0 22,096 27,812 201,4632001 44,747 29,153 29,697 22,483 8,212 29,290 2,537 303 11,905 31,932 7,133 50,112 267,5032002 9,037 11,881 11,340 35,381 1,898 0 825 1,025 2,227 2,049 1,039 24,831 101,5342003 26,914 20,190 35,459 4,840 7,160 20,928 3,941 2,521 739 74 454 192 123,4122004 4,737 36,298 49,827 7,882 39,164 59,135 23,060 472 0 1,071 14,344 19,597 255,5862005 19,561 25,775 8,910 7,341 0 0 0 0 53 0 0 0 61,6402006 40 226 34,062 4,257 885 0 0 0 0 0 0 766 40,2352007 30,613 5,064 464 4,187 17,851 24,873 51,114 27,604 1,037 0 46 5,633 168,4862008 4,860 32,400 56,253 48,103 24,904 1,392 1,652 4,863 9,832 5,441 6,976 3,719 200,396
Min 0 0 0 468 0 0 0 0 0 0 0 0 22,845Ave 22,422 24,500 30,499 21,831 21,353 14,497 7,862 2,817 4,495 6,422 11,339 23,335 191,374Max 65,520 65,885 67,337 65,304 72,468 59,135 51,114 39,148 50,813 42,938 73,436 78,067 402,323
DRAFT
Appendix F 19
Conclusions
The purpose of this exercise has been to demonstrate how the narrative standards developed for Black and Little
Cypress could be implemented and evaluated. Refinements to this approach that this exercise might suggest could
include a move towards more of a percent of maximum approach, for instance the maximum diversion rate could
be set at one value for mid range flows from 250‐1000 cfs and a higher at higher flows, thus allowing additional
scalping of flood flows while still preserving much of the natural function. Selecting the appropriate diversion rate
remains an issue that will require additional discussion and while additional scientific understanding may be
brought to bear, this decision will likely include a negotiated balance between the desire to maintain a more
pristine state, particularly for Black Cypress, and the needs for out of stream water supply. Finally, for the
approach used for Little Cypress, the quantification and ecological value of overbank flows is critical as is the value
of in channel pulses, to providing a sound basis on which to make these decisions.
DRAFT
Appendix G 1
APPENDIX G INDICATORS {The ideas included in this draft document are only intended as a starting point for the development of a workplan
to begin the process of adaptive a management.}
As the Cypress‐Flows Project (CFP) proceeds, it will need to evaluate how well implementation of the flow regimes,
flow standard and set aside accomplish the goal of protecting the ecological health of lakes, rivers and streams of
the Cypress Basin. Although a general objective for such protection was clearly articulated at the beginning of the
Project, , and research goals set, in part, for base line data for such evaluations, a clear set of specific measures to
assess ecological health were not defined. Development of indicators and an analysis of the data available or that
should be collected for an appropriate set of indicator was begun in 2009.
The goal of this work is to identify specific quantifiable indicators so that the efficacy of the proposed flow regime
can be evaluated through adaptive management. A sound ecological environment is one that maintains the
integrity and function of the natural system. It has the things that it should have, richness and diversity of plants
and animals, and it does the things it should do, maintain water quality, move sediments, and connect the riverine
and riparian area and flood plains.
Review of historical data suggests that the plant and animal communities have changed partially in response to
human alterations. The fish community appears to have shifted from assemblages dominated by cyprinids,
percids, cyprinodontids in the 1950's to assemblages dominated by centrachids, other cyprinids, clupeids, and
artherinids by the 1980's. The plant community of this wetland of international importance has developed a more
homogeneous age structure likely due to the stabilization of flows by upstream impoundment. Water quality
concerns related to dissolved oxygen, nutrients, bacteria and mercury have been identified. Although sediment
loadings have not been measured, it is reasonable to assume that major impoundments have captured a high
proportion of sediment and this may have implications for channel morphology.
The best available science on environmental flows predicts that maintaining key components of the natural flow
regime is the safest and surest way to maintain and restore ecological health. Preliminary flow recommendations
have identified the key components of that regime. These will be implemented via an adaptive management
approach. The success of this approach will be evaluated based on the resource response. Specifically the resource
should show maintenance of species richness and diversity, support of a heterogeneous age class of wetland
plants, reduction of human induced water quality concerns and maintenance of in channel habitat conditions.
Indicators
There are multiple aspects of the structure and function of a “sound ecological environment” or a river’s ecological
integrity. Measurement of an ecosystem’s condition and monitoring of restoration or management objectives
should consider these aspects. In addition, due to limited resources and time, monitoring programs must be as
efficient and focused as possible.
The Texas Instream Flows Program (TIFP) has proposed a system for developing objectives for meeting goals for
each priority study segment and developing indicators to monitor progress. The framework is also very similar to
and highly compatible with the way that The Nature Conservancy sets conservation objectives and monitors
success (TNC 2001). Thus, CFP can utilize an approach based on the TIFP framework to monitor implementation of
flow building blocks and to guide adaptive management.
DRAFT
Appendix G 2
Flow recommendations were developed based on review of existing data and in some cases model simulations of
instream habitat, water quality, sediment transport, and watershed connectivity. The goal of the flow
recommendations is to protect a sound ecological environment, which is defined as a condition that maintains the
integrity and function of the riverine system. Although some site‐specific data and analysis was available to link
flows to a ecological resource response, via the intermediate steps of analysis of water quality, habitat, sediment
transport and connectivity, the recommendations were in good part based on an application of the natural flow
paradigm which states that a sound ecological environment is maintained by maintaining critical component of the
natural flow regime. The recommendations are now being evaluated and refined within an adaptive management
context and the effectiveness of the recommendation on meeting the goal will be evaluated on several levels.
Relationship to ecological health and timeframe of ecological response
A critical piece of the process of adaptive management is the monitoring of specific and quantifiable measures of
the ecosystem response. As outlined in the TIFP, useful ecological indicators share a number of important
characteristics. They may have "intrinsic importance (measure a species or process directly)," perhaps serve as an
early warning or sensitive indicator or they may serve to stand in for a process (TIFP 2008). Other important
considerations are cost and ease of monitoring and the availability of historical or baseline data against which
comparisons can be made. Each of these issues should be considered when selecting among the many choices of
available indicators. Unfortunately, the most comprehensive measures of ecosystem health are the ones that
typically take the longest to see a response to changes in water management and are the most difficult to
measure. Changes in species richness and diversity fall in this category. Deviation from flow recommendations are
relatively easy to monitor, however the prediction of ecological response to these deviations carries more
uncertainty.
A simplistic model of a general approach used to develop an instream flow recommendation is illustrated in Figure
12.
ResourcesConditionsManagment/
Implementaiton
Flows
Water Quality
Sediment Transport
WatershedConnectivity
Habitat
SoundEnvironment
(function and integrity)
Figure 12 Multilevel indicators of ecological health.
DRAFT
Appendix G 3
Resource level measures of ecosystem integrity and function apply to the riverine "resources" including biological
measures such as species richness and diversity, and riverine functions such as the ability to assimilate wastewater
and to maintain river channels. While these measures are desirable, detecting a response in these resources to a
change in water management is often difficult and it may be years before this response is detected. These delayed
responses can be counteracted somewhat by the selection of relatively more sensitive attributes such as early life
stage responses or recruitment success, but there is no getting around the fact that detection of community level
effects will require a significant level of time and resources. With the next level of indicator, mid‐term/ conditions,
rather than directly evaluate the "resource" response, indicators measure the response of the "conditions" that
are necessary to maintain those resources (i.e. measurement of habitat, water quality, sediment transport and
connectivity). These indicators might also be viewed as analysis or model verification. If a habitat model predicts
that a certain flow rate will provide a specific amount of available riffle habitat these indicators can be used to
verify this prediction and if necessary refine or recalibrate the model to improve these predictions. The final
indicator level, short‐term/management might be viewed as an indicator of the implementation success. These
indicators address the question of whether the water management plan produces the prescribed flow
recommendations. These include not only the various magnitudes, frequencies, durations and timing prescribed in
the building blocks but also the desired attainment frequencies at which these recommendations should be
achieved. As such, development of these indicators is integrated with the development of various triggers that will
be necessary to allow operators to implement these recommendations and a consideration of other factors related
to water supply, operational constraints and values associated with other water uses. These indicators may also
take different forms when considering real time operations and long term planning or water rights permitting.
While monitoring of these various types of indicators can take place concurrently, there is a logical progression
from the short‐term/management to the mid‐term/conditions and finally the long‐term/resource level measures.
If the water management implementation plan is not achieving the desired flow conditions, it is impossible to
evaluate the resource response to the flow recommendations. The process of adaptive management addresses
this issue by providing for evaluation of response to specific flow conditions. However, even these evaluations will
likely be limited to mid‐tem intermediate indicators.
Thresholds
Before discussing the specifics of each indicator, an issue that requires some attention is a discussion of how
achievement of these indicators is assessed. This leads directly to a discussion of thresholds. The natural flow
paradigm suggests that healthy aquatic systems do not require strict adherence to precise flow targets but rather
that the natural range of variation in flow levels and events will maintain a broad suite of ecosystem resources.
While it is not necessary to conserve the entire range of variation, it is necessary to conserve the ecosystem so that
it remains within some appropriate limits to this variation. Identifying such thresholds provides a scientific,
objective basis for saying whether a sound ecological environment is intact. The minimal conservation goal for an
ecosystem should be to ensure that all of its ecological indicators are within the bounds of their critical ecological
thresholds or “minimum integrity thresholds” (TNC 2001; Parrish et al. 2003). This provides an explicit definition of
what acceptable conservation means, and hence an explicit basis for rating the ecosystem’s status.
The Minimum Integrity Threshold for an ecological indicator is the outer limit of its acceptable range of variation.
Once this threshold has been crossed, the overall integrity of the river cannot be restored so long as the altered
indicator is outside of its range of acceptable variation. The composition, structure, and function of a river may not
begin to degrade immediately when one of its indicators moves outside of its acceptable range of variation.
However, we can expect this shift to set in motion chains of events, that will (if unchecked) result in additional
alterations to other indicators and leave them vulnerable to significant disruptions from additional disturbances,
DRAFT
Appendix G 4
that in turn will push them still further outside of their acceptable ranges of variation. Defining the Minimum
Integrity Threshold for individual indicators is the mechanism by which scientific knowledge of the river influences
the Ecological Integrity rating. This threshold becomes the fixed dividing line between ratings of Good (or better)
and Fair (or worse) for each indicator. Therefore, this is the principle threshold that will help define a consistent,
scientifically defensible means of rating the integrity of the river.
The idea of “minimum integrity thresholds” comes from the concept of “natural range of variation”:
Each key ecological factor for a target will have a natural range of variation. Key ecological factors such as species
population sizes; river flows; water quality, sediment transport, frequency and area of riparian inundation all
naturally vary within certain ranges.
There are recognizable patterns to this variation, which can be described in terms of frequency, timing, duration,
and limits of variation. This pattern includes both “normal” variation and extreme disturbances.
Natural communities and ecological systems recover from extreme disturbances ‐‐ although this may take a long
time.
A naturally functioning target can generally only be driven beyond its natural range of variation and ability to
recover (breakdown of resistance and resilience) by disturbances foreign to the system.
“Minimum integrity thresholds” are those boundaries beyond which the target loses its natural ability to recover.
Planning teams can use key factors as tools to define a desired future status for each conservation target by setting
thresholds that define the preferred status for each key factor. These conservation area‐defined Optimal Integrity
Thresholds are the means to measure the improvement of a target’s key factors beyond their minimum integrity
DRAFT
Appendix G 5
thresholds and toward the more ecologically desirable status at the conservation area. To receive a “Very Good”
rating, a key factor must:
Be less vulnerable to being pushed outside its acceptable range of variation by chance events or human
caused disturbances perturbations, and therefore is perceived with greater confidence to be “secure”,
and/or,
Require little to no human intervention to be maintained within its acceptable range of variation, and/or,
More closely approximate what is best known as its “natural state” or functions within its “natural range
of variation.”
Conservation targets with one or more key ecological factors outside their minimum integrity thresholds cannot be
considered “conserved”, and should be rated as “Fair” or “Poor” in this framework. Planning teams again can use
key factors as tools to distinguish between these two rating levels, by defining Imminent Loss Thresholds for each
target’s key factors. These conservation area‐defined thresholds are means to measure the improvement of a
target’s key factors toward their minimum integrity thresholds, when they are severely altered. To receive a
“Poor” rating, a key factor must be so severely altered from its minimum integrity threshold, that allowing it to
remain in this condition or trajectory for another 10‐25 years will make restoration of the target or prevention of
its extirpation practically impossible. The rating thus takes into account the magnitude of alteration, the possible
reversibility of this alteration, and the ecological consequences of allowing the alteration to persist.
DRAFT
Appendix G 6
Figure 13 Key Factor Thresholds and Status Assessment
Indicators specific to riverine components
Key factors for indicators for the main riverine categories (hydrology and hydraulics, biology, water quality,
geomorphology and connectivity) will be described, including the quantifiable metric that will be used, threshold
targets, and a workplan proposed to evaluate their status. There is an order in which the indicators should be
evaluated. Although it is necessary to monitor baseline conditions before implementing a flow recommendation,
there is no point in evaluating the species richness response to a flow recommendation (a biological long
term/resource level indicator of ecosystem health) unless it has first been determined that the recommended
flows are actually being provided to the river (a hydrologic short‐term/management indicator). While this
chronological or bottom up approach to discussing indicators has some appeal the overall goal is to protect a
sound ecological environment and a long term/resource indicators thus indicators will be discussed from this top
down perspective. Starting from the end goal and working backward to the intermediate indicators that are
necessary precursors to these goals.
DRAFT
Appendix G 7
Long‐term/Resource Indicators
The overall objective of the Cypress Caddo SRP is to maintain a sound ecological environment, which includes
maintaining the plant and animal that comprise the aquatic community. The success in restoring or maintaining
these resources is measured in terms of native richness and diversity of plants and animals. This may require
special emphasis on the protection of species of concern (including threatened and endangered).
Indicators of Biological Integrity (IBI) are used to dictate the level of protection streams receive in accordance with
surface water quality standards. They are used in conjunction with water quality, benthic macroinvertebrate and
habitat data to set aquatic life use in wadeable streams (exceptional, high, intermediate, or limited). Using the IBI's
as a starting point the CFP will determine if the regional is IBI, or components of that index are well suited to be
used as indicators of the ecological health of the aquatic community that is responsive to flow alterations. It is
possible that the metrics and rating thresholds will need to be modified to provide accurate and meaningful
assessment of Cypress basin fish communities.
Specific Indicators, thresholds and a workplan to assess these criteria will be developed.
Mid‐term/Conditions Indicators
These are indicators of the conditions that are believed to be necessary in order to have a sound ecological
environment. They include flow dependent habitat suitable for the species or guilds identified above, channel
maintenance (cleaning riffles scouring pools etc.), suitable water quality conditions and periodic inundation of
identified wetland areas. These intermediate indicators bridge the gap between the flows or hydrology produce
by the implementation of a water management plan the ecological response of the system. Predictions of these
conditions (i.e. available habitat or area of inundation at a given flow rate) have been made based on models or
other types of analysis. These indicators can be used to verify and if necessary modify these predictions.
Indicators in this groups will include those that evaluate Instream Habitat (Biology/Hydraulics), Riparian/Wetland
Connectivity (Biology/Hydraulics), Water Quality and Channel Maintenance (Geomorphology)
Short‐term/Management indicators
Before any resource measures of ecosystem response to recommended flows can be evaluated, it will be
necessary to implement the flow recommendations and evaluate whether the prescribe flows are indeed observed
at their prescribed magnitudes, frequencies, durations, and timing. Although this is in many ways the most
straightforward of all of the indicators, it presents a number of challenges that need to be addressed, including
translating the building blocks recommendations into target hydrographs, addressing implementation and water
supply constraints, and practical management issues like the development of triggers to identify hydrologic
conditions and the time frame over which to specify these conditions (e.g. is the hydraulic condition reevaluated
every day, month, season, or year?). Finally, there needs to be some discussion the period of time needed to make
an assessment. If the recommendations call for base dry conditions 30 percent of the time does that mean 30
percent of the time over the next year or next ten years? With hydrologic indicators, unlike many of the other
indicators, models exist to forecast future flow conditions. In Texas the model that is used is call a WAM (Water
Availability Model) which overlays current and future water demand projections on historical flows in order to
estimate future flows. The WAM is not without its shortcomings an important one being that it runs on a monthly
time step whereas most analysis of environmental flows requires a finer time step, probably daily. Accepting the
WAM limitations and employing techniques to address them, allows for an assessment of hydrologic indicators
over a time frame that is comparable to the time frame of the basic data that was used to develop the preliminary
DRAFT
Appendix G 8
recommendations (approximately 40 years). While this time frame may not be suitable for a real time assessment
(we can't wait 40 years to know if the flow recommendations have been adequately implemented) they can
provide some direction as to what appropriate expectation should be on short timeframes.
REFERENCES
Parrish, J.D., D.P. Braun, and R.S. Unnasch. 2003. Are we conserving what we say we are? Measuring ecological
integrity within protected areas. BioScience 53: 851‐860.
The Nature Conservancy. 2001. Assessing the ecological integrity of conservation targets in site conservation
planning and measures of success.