habitat suitability for steelhead in the upper sisquoc river watershed

Habitat Suitability for Steelhead (Oncorhynchus mykiss) in the Upper Sisquoc River Watershed,

Santa Barbara County, CA

Technical Memorandum

Prepared for Ocean Protection Council 1330 Broadway, 13th Floor

Oakland, CA 94612-2530 and

California Department of Fish and Game 830 S Street

Sacramento, CA 95811

Prepared by Stillwater Sciences

P.O. Box 904 Santa Barbara, CA 93102

February 2012

Technical Memorandum Aquatic Habitat Suitability for Steelhead (O. mykiss) in the Upper Sisquoc River

February 2012 Stillwater Sciences

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Suggested citation: Stillwater Sciences. 2012. Habitat Suitability for Steelhead in the Upper Sisquoc River Watershed, Santa Barbara County, CA. Prepared by Stillwater Sciences, Santa Barbara, California for California Coastal Conservancy, Oakland, California and California Department of Fish and Game, Sacramento, California.



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Table of Contents

1 INTRODUCTION ..................................................................................................................1

2 HSI MODEL OVERVIEW.................................................................................................... 1

3 STUDY AREA.........................................................................................................................2

4 METHODS ..............................................................................................................................6

4.1 Site Selection ............................................................................................................... 6 4.2 Field Methods ............................................................................................................ 10

4.2.1 Habitat typing...................................................................................................... 11 4.2.2 Habitat variables.................................................................................................. 11

4.3 Analytical Methods.................................................................................................... 13 4.3.1 Habitat variables.................................................................................................. 13 4.3.2 Habitat suitability index curves ........................................................................... 14 4.3.3 Model component and HSI scores....................................................................... 15

5 RESULTS ..............................................................................................................................15

5.1 Study Site Channel Types.......................................................................................... 15 5.2 Study Site Habitat Types ........................................................................................... 15 5.3 Water Temperature .................................................................................................... 16 5.4 Habitat Variables ....................................................................................................... 18 5.5 HSI Scores ................................................................................................................. 20

5.5.1 Individual habitat-variable scores ....................................................................... 20 5.5.2 Study site model component and channel type scores ........................................ 22 5.5.3 Sub-basin and watershed-wide scores ................................................................. 23

5.6 Comparison with Other Watershed HSI Scores......................................................... 23

6 DISCUSSION ........................................................................................................................26

6.1 Habitat Conditions ..................................................................................................... 26 6.1.1 Fire and flood frequency ..................................................................................... 26 6.1.2 Effect of fires and floods on fish habitat ............................................................. 27

6.2 HSI model sensitivity................................................................................................. 28 6.3 Fish Observations ...................................................................................................... 28

7 LITERATURE CITED ........................................................................................................ 29



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Tables Table 1. The total length of channel and percent of total length within each channel type

category. ........................................................................................................................ 8 Table 2. The number of study sites selected and the number of potential sites within each

channel type category. ................................................................................................. 10 Table 3. CDFG Level II and Level IV habitat types. ................................................................ 11 Table 4. O. mykiss habitat variables .......................................................................................... 12 Table 5. Model variable calculation. ......................................................................................... 14 Table 6. Study site channel type designations. .......................................................................... 15 Table 7. Habitat types and percent composition at study sites. ................................................. 16 Table 8. Summer water temperatures at study sites with temperature data loggers. ................. 16 Table 9. Average daily maximum summer water temperatures during July–August at study

sites with temperature data loggers and corresponding HSI sites ............................... 18 Table 10. Habitat variable measurements.................................................................................... 19 Table 11. Study site HSI scores................................................................................................... 21 Table 12. HSI scores for model components at study sites and for channel types. ..................... 22 Table 13. Basin- or reach-scale HSI scores for the upper Sisquoc River and subbasins, and

other central and southern California watersheds reported in TRPA. ......................... 24 Figures Figure 1. Santa Maria River Watershed........................................................................................ 4 Figure 2. Upper Sisquoc River Watershed.................................................................................... 5 Figure 3. Channel types within the upper Sisquoc River watershed............................................. 7 Figure 4. Study sites in the upper Sisquoc River watershed. ........................................................ 9 Figure 5. Daily minimum, maximum, and average water temperatures at study sites with

temperature data loggers during June–August 2011. .................................................. 17 Figure 6. Channel type/reach-scale HSI scores for the upper Sisquoc River and other central

and southern California watersheds............................................................................. 25 Appendices Appendix A. Field Survey Data Appendix B. HSI Curve Coordinates Acknowledgements We sincerely thank Matt Stoecker for his assistance with study site selection and sharing his knowledge of and extensive experience in the upper Sisquoc River watershed with us.



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1 INTRODUCTION

An assessment of habitat suitability for steelhead, the anadromous life history form of Oncorhynchus mykiss, in the upper Sisquoc River watershed was included as a component of the Santa Maria River Instream Flow Study. The Sisquoc River watershed supports a self-sustaining population of resident rainbow trout (the resident life history form of O. mykiss) (Davis and Jackson ca. 1934, Evans 1947, Douglas and Richardson 1959, Edwards et al. 1980, Kautzman and Uyehara 1999, and others, all as cited in Becker and Reining 2008; Shapovalov 1944; Cardenas 1996; Boughton and Fish 2003; Stoecker 2005), and spawning of adult steelhead is observed during some years (Shapovalov 1944, Shapovalov 1945, Titus et al. 2006, Stoecker 2005). The Sisquoc River watershed provides the only available perennial habitat for steelhead to spawn and rear in the Santa Maria River watershed, and is designated critical habitat for the Southern California Steelhead Distinct Population Segment (DPS) (70 CFS 52488). California Department of Fish and Game (CDFG) requested that this habitat assessment utilize the U.S. Fish and Wildlife Service’s (USFWS) Habitat Suitability Index (HSI) model approach (Raleigh et al. 1984) (see Section 3.1). The objectives of the assessment are to: 1) describe the quantity and quality of steelhead spawning and rearing habitat at selected, representative sites in the upper Sisquoc River watershed; and 2) determine whether suitable habitat conditions are available to anadromous adults during years when they are able to access this habitat and to their progeny during subsequent years. The results of the HSI analysis demonstrate the relative value of the Sisquoc River watershed for O. mykiss, provide comparison to other recent HSI studies in nearby watersheds, and assist CDFG in supporting stream flow recommendations for the Santa Maria River.

2 HSI MODEL OVERVIEW

Here we provide a brief overview of the HSI model and approach used for this study. This report is not intended to provide a comprehensive description of the model developed by Raleigh et al. (1984) or summarize other regional HSI studies, but rather to provide a description of the methods and results specific to this study. Please refer to source documents for detailed descriptions of the HSI model and other studies in the region used to inform this study. The USFWS has developed HSI models for a variety of species including birds, mammals, and fish among others to describe habitat quality and to assist with environmental impact assessments. The particular HSI model used for this study was developed for rainbow trout (O. mykiss) and includes adjustments to model parameters for evaluating the anadromous life history form (i.e., steelhead) (Raleigh et al. 1984). This model has been used by CDFG and others as a standardized approach to assess habitat quality for O. mykiss including streams along the southern and south-central California coast where anadromous forms are currently listed (NMFS listings 5 January 2006 [71 FR 834]). We used the model specifically developed for assessing riverine habitat and included habitat variables and model components modified for steelhead where suggested. This HSI model uses 18 habitat variables grouped into five life stage-specific model components (adult, juvenile, fry, embryo, and “other”). Each model variable has a relationship of habitat suitability over a range of potential habitat variable values which is expressed as an index score (i.e., scores range from 0 to 1.0). The model components each comprise a subset of the 18 habitat variables related to the habitat requirements of the particular life stage. The model components



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for adult and juvenile life stages include steelhead-specific sub-models, whereas the model components for fry, embryo, and “other” do not (are the same for resident and anadromous forms of O. mykiss). Field measurements of habitat variables are used to calculate index scores for each variable using the habitat suitability index relationships (HSI curves), and combined using the HSI model described by Raleigh et al. (1984), to determine a HSI score considering all life stages. The model is designed on the premise that extreme variable values limit habitat carrying capacity rather than average values, and thus low individual habitat variable index scores (suitability <0.4) can strongly influence resulting HSI scores. The model is strongest in its inclusion of a wide range of habitat variables that are generally well-accepted as controlling the quality of O. mykiss habitat, and its combination of these habitat variables into a single value, which can be easily compared with results from similar studies. Limitations of the approach, however, include the representation of complex systems with simple index values where important details may be suppressed, or where habitat elements not considered in the model are actually important. As with any model, understanding the underlying assumptions of the model and the sensitivity of the model results to input parameters are important factors for interpreting the results. For this study, we stratified the channel network based on physical attributes, and selected 12 sites (total) within the four resulting channel type categories. HSI scores were calculated for each site, and composite scores for each channel type were calculated using the HSI model. The channel type scores were extrapolated to reaches not sampled to determine basin-wide scores for the upper Sisquoc River watershed and the three sub-basins for comparison with other basins. Raleigh et al. (1984) did not describe site selection procedures or field methods (which are described in Sections 3.2 and 3.3 of this document), limiting their descriptions to the habitat variables and suitability relationships, model components, and HSI score calculations. Additional descriptions of the HSI curves, habitat variables, and model components are provided in Section 3.4 of this document. See Raleigh et al. (1984) for a full description of the HSI model used for this study.

3 STUDY AREA

The Sisquoc River watershed is one of three main sub-watersheds, in addition to the Cuyama and Santa Maria rivers, comprising the Santa Maria River watershed (Figure 1). This study focuses on the portion of the Sisquoc River watershed upstream of and including Horse Creek, which includes the Sisquoc River, Manzana Creek, and Horse Creek (Figure 2) (hereafter referred to as the upper Sisquoc River watershed). This study area boundary corresponds with the large contiguous area of the Sisquoc River watershed within public ownership (USDA Forest Service Los Padres National Forest) and where access for field sampling was feasible. The upper Sisquoc River watershed has a drainage area of approximately 637 km2, which is 52% of the total Sisquoc River watershed. The Sisquoc River upstream of Manzana Creek, Manzana Creek, and Horse Creek sub-watersheds make up approximately 67%, 23%, and 9% of the upper Sisquoc River watershed, respectively. The remaining 1% of the watershed area drains directly into the Sisquoc River between Horse and Manzana creeks. The upper Sisquoc River watershed lies within the Los Padres National Forest and drains the San Rafael mountains and the west slope of the Sierra Madre mountains. Elevations in the upper watershed range from 322 m, where the Sisquoc River crosses the USDA Forest Service property



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boundary in the west, to 2,081 m at Big Pine Mountain, the highest point in the San Rafael mountain range in the southern headwaters of Manzana Creek. Geology is the upper watershed is characterized by old, competent plutonic basement and metasedimentary rock along steep mountain ranges. The Sisquoc River watershed has a typical Mediterranean climate with warm dry summers, moderate winters, and the majority of precipitation occurring during winter and spring. Most precipitation falls as rain, although snow is common in the higher elevations. Average annual precipitation in the upper Sisquoc River watershed ranges from 38–127 cm, which is the highest in the greater Santa Maria River watershed (Figure 2) (PRISM Climate Group 2011, USFWS 2011). Vegetation is predominantly chaparral and oak woodland with occasional stands of pine and fir trees, and a riparian corridor of willow and alder along stream channels.



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Figure 1. Santa Maria River Watershed. The upper Sisquoc River watershed HSI study area is outlined in red and expanded in Figure 2.


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Figure 2. Upper Sisquoc River Watershed.



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4 METHODS

4.1 Site Selection

Study sites were selected using a stratified random sampling approach, described below, based on, channel gradient, drainage area (a surrogate for channel size and elevation), and access considerations, and limited to those reaches within potential steelhead distribution. In order to collect the maximum amount of habitat information in two four- to five-day field efforts (a limitation imposed by project scoping and budget), we concentrated data-collection efforts regionally and within individual study sites to limit overall travel distances required. The channel stratification and site selection approach used for this study is consistent with landscape-scale fish habitat assessments. A channel network was developed in GIS as the basis for channel stratification, site selection, and eventual extrapolation of HSI scores from individual study sites to unsurveyed portions of the upper Sisquoc River watershed. Stream reaches downstream of steelhead migration barriers identified by Stoecker and Stoecker (2003) were considered potentially accessible by steelhead and were included in the site selection process and subsequent analyses. In total, 185.6 km of channel were included. These channels were stratified into two channel gradient categories (0–4% and >4%) and three drainage area categories (≤100 km2, 100–250 km2, and >250 km2). Channel gradient thresholds relate to channel morphologies that give rise to different habitat attributes and relate directly to the quality and quantity of habitat used by steelhead. Low to moderate gradient channels (0–4%) generally relate to pool-riffle and plane-bed channel morphology, whereas steeper channels (>4%) generally relate to step-pool and cascade channel morphology (Montgomery and Buffington 1997). Drainage area thresholds relate to spatial patterns of drainage area observed in the upper watershed using GIS to define smaller channels and tributary reaches extending to high elevations, moderately-sized mainstem reaches, and large low-elevation mainstem reaches (Figure 3).


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Figure 3. Channel types within the upper Sisquoc River watershed.



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The total length of channel within each channel type was calculated using GIS and used to assess the relative occurrence in the Upper Sisquoc River Watershed. Four of the six channel type categories had sufficient length for inclusion in the assessment, including the three low-gradient channel types and high-gradient channels with small drainage areas (Table 1).

Table 1. The total length of channel and percent of total length within each channel type category.

Channel gradient 0–4% >4%

Grand total Drainage area (km2) Channel

length (m) % of total

length Channel


length Channel


length <100 38,748 21 90,315 49 129,063 69 100–250 32,319 17 261 0 32,580 18 >250 23,911 13 13 0 23,924 13 Totals 94,978 51 90,589 49 185,567 100

Three primary access points were identified that would allow foot access to a diversity of stream and habitat types in the upper Sisquoc River watershed: (1) the vicinity of Nira and Davy Brown campgrounds on Manzana Creek, (2) Manzana Schoolhouse campground near the confluence of Manzana Creek and the Sisquoc River, and (3) Judell Creek trailhead off Big Pine Road (Figure 4). Portions of the watershed greater than about 3 km from these access points were excluded as part of the site-selection process.



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Figure 4. Study sites in the upper Sisquoc River watershed. Numbers indicate unique study site identification number.



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Additional criteria ensured potential sites had sufficient length and minimized large changes in drainage area within a potential site. Potential study sites included 760 m of contiguous channel length within a single gradient/drainage-area category, and were not intersected by a major tributary. A total of 45 potential study sites meeting all of the channel-type, length, and accessibility criteria were identified (Table 2). Twelve study sites, the number of sites that could be surveyed under the task scope, were selected from this list. The number of randomly selected sites within each channel type category were based on the relative length of channel within each channel type category (Table 2). One or more alternate study sites were also selected in case field conditions warranted reselection. Locations of the final study sites surveyed are presented in Figure 4.

Table 2. The number of study sites selected and the number of potential sites within each channel type category.

Channel gradient 0–4% >4%

Grand total Drainage area (km2) # of sites

selected # of potential

sites # of sites selected

# of potential sites

# of sites selected

# of potential sites

<100 2 9 6 14 8 23 100–250 2 15 0 0 2 15 >250 2 7 0 0 2 7 Totals 6 31 6 14 12 45

4.2 Field Methods

Each study site was surveyed twice, first in June 2011 and again in October 2011, to collect habitat suitability data under a range of seasonal conditions. A different suite of habitat variables was collected during each survey. The first survey was conducted 6–10 June 2011 to collect habitat data during the spring base flow period. The downstream end of each study site was located using a handheld GPS, and the location of the starting point was recorded. The length of each study site was variable and based primarily on the length that could be surveyed within the time available. Field guidelines developed for sampling study sites included: (1) a target length of 300 m (1,000 ft) and at least five pool, riffle, and flatwater units; (2) a minimum length of 150 m (500 ft) and at least three pool, riffle, and flatwater units; and (3) a maximum length of 760 m (2,500 ft) for wide channels. Within each study site, habitat units were identified (see Section 3.2.1) and their length and width were measured with a hip-chain and stadia rod, respectively. A subset of habitat variables representative of base flow conditions were measured at each habitat unit according to Raleigh et al. (1984) (see Section 3.2.2), and one or more habitat units were photographed to document conditions at the study site. Upon reaching the end of the study site, the upstream end of the site was recorded with GPS. Six Onset Tidbit v2 temperature data loggers were also deployed during the June 2011 survey to characterize water temperatures in the three main survey areas. Specifically, a temperature data logger was deployed at the Sisquoc 1.1 and 5.3, Manzana 6.3 and 7.1, Davy Brown 12.1, and Judell 14.2 study sites (see Figure 4).



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The study sites were resurveyed 17–21 October 2011 to collect a different suite of habitat variable data representative of the fall low-water period. The downstream end of each survey site was relocated, and habitat variables were measured at the same habitat units that were surveyed in June. Additional photographs were taken at various habitat units and the temperature data loggers were retrieved.

4.2.1 Habitat typing

During the June 2011 survey effort, discrete habitat units in each study site were identified using CDFG’s Level IV habitat type classifications (Flosi et al. 1998). Each habitat unit was designated as one of seventeen Level IV habitat types (Table 3). Level II habitat types (i.e., riffles, flatwaters, and pools) were eventually used in the HSI model.

Table 3. CDFG Level II and Level IV habitat types.

Level IV Level II

Code Description CAS Cascade HGR High gradient riffle LGR Low gradient riffle

Riffles

BRS Bedrock sheet RUN Run GLD Glide POW Pocketwater

Flatwaters

SRN Step run MCP Mid-channel Pool LSBo Lateral Scour Pool, boulder formed LSBk Lateral Scour Pool, bedrock LSL Lateral Scout Pool, log enhanced LSR Lateral Scour Pool, root-wad enhanced TRP Trench pool DLP Dammed pool CRP Corner pool

Pools

STP Step pool

4.2.2 Habitat variables

Habitat variables, as defined by Raleigh et al. (1984), were measured for each study site. Some habitat variables were measured at each habitat unit (e.g., instream cover, shade), whereas others that are not expected to vary by unit are measured at one location for the site (e.g., pH and dissolved oxygen [DO]). The 18 habitat variables used in the model are listed in Table 4 including those with more than one version, and are discussed in terms of their use in the HSI model in Section 3.3. Certain variables were measured during the spring base flow period, others during the fall low-flow period, some were measured during both periods to determine the habitat conditions for different O. mykiss life stages. Continuous water temperatures were collected at 6 locations during the summer and early fall (June to October 2011). Data from this sampling period were used to assess summer rearing conditions, but these data did not include the egg incubation or adult migration periods. Periodic daytime water temperature data were available at the U.S. Geological Survey (USGS) Sisquoc River near Sisquoc gage (USGS 11138500) (hereafter referred to as the Sisquoc gage) and used for characterizing conditions during periods when site-specific water temperatures were unavailable (November–May). Continuous stage (i.e.,



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flow) data was not collected for this study. The periods under which habitat variables were measured in study site habitat units are summarized in Table 4. For water-temperature variables, only those periods used to calculate the variable measurement used in the analysis are reported.

Table 4. O. mykiss habitat variables (based on Raleigh et al. 1984).

Habitat variable

code Habitat variable description

HSI model component

O. mykiss life stage Measurement period

(in 2011)

V1am Average maximum water

temperature Adult migration July–August

V4 Average thalweg depth Rearing Fall V6a % instream cover Rearing Fall V10 % pools Rearing Spring V15 Pool class rating

Adult

Rearing Fall

V2sm Average maximum water

temperature Smolt migration July–August

V6j % instream cover Rearing Fall V10 % pools Rearing Spring V15 Pool class rating

Juvenile

Rearing Fall V8 % substrate 10–40 cm diam. Overwinter, rearing Spring

V10 % pools Rearing Spring

V16rr % fines in riffle/run and

spawning areas

Fry Food production Spring

V2inc Average maximum water

temperature Incubation July–August

V3inc Average minimum DO Incubation Fall

V5 Average velocity over spawning

areas Incubation Spring

V7 Average substrate size in

spawning areas Incubation Spring

V16sp % fines in riffle/run and

spawning areas

Embryo

Incubation Spring and fall

V1r Average maximum water

temperature Rearing July–August

V3r Average min dissolved oxygen Rearing Fall V9 Dominant substrate in riffle/run Food production Spring

V11 Average % vegetation and

ground cover Food production Spring

V12 Average % rooted vegetation and

stable rocky ground cover All Spring

V13 Annual max/min pH All Spring and fall V14 Average annual base flow Rearing Spring and fall

V16rr % fines in riffle/run and

spawning areas Food production Spring and fall

V17 % overhead shading Rearing, food

production Spring and fall

V18 Average % flow during adult

migration

Other

Adult migration Year-round

Variables related to spawning (e.g., V7 and V16) were measured at gravel patches considered potentially suitable for spawning. Vegetation, shade, and substrate variables (e.g., V8, V11, and



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V17) were estimated visually along with the pool class rating (V15). Water velocities were estimated visually and depths were measured with a stadia rod. Dissolved oxygen and pH were measured using an YSI 85 (YSI Inc.) and a handheld pH meter (EcoTestr pH 2, Oakton Instruments), respectively. Although temperature was collected periodically during the field surveys, the HSI model uses data collected from the temperature data loggers that were deployed from June through October 2011. Mean, minimum, and maximum water temperatures were calculated for the summer period (June–August). The maximum weekly average temperature (MWAT) was also calculated for each site to allow comparisons with other studies. The MWAT is the maximum temperature of the seven-day rolling average of average daily temperatures, and describes ambient water temperature conditions over the previous week. In addition, some variables rely on long-term or continuous water temperature and flow data (e.g., V14). For these, water temperature and flow data from the Sisquoc gage were used.

4.3 Analytical Methods

The HSI model, as described by Raleigh et al. (1984), provides HSI curves for the 18 habitat variables and guidance for calculating model component and HSI scores. HSI curves are relationships (graphs) of habitat suitability expressed as an index value, with 1.0 being fully suitable and 0.0 being unsuitable, over a range of possible habitat variable values. In some cases HSI curves from other studies were used when they were modified to represent conditions for O. mykiss populations in southern California. Field measurements of habitat variables for each study site are used to calculate index scores for each variable using the HSI curves. These habitat variable scores provide input to the HSI model to determine both model component scores and HSI scores. Model component scores were calculated using the riverine model and the equal component value method described by Raleigh et al. (1984) was used to determine HSI scores for all life stages combined.

4.3.1 Habitat variables

The habitat variables measured and used in the HSI model are summarized in Table 4; a detailed description of these variables is provided by Raleigh et al. (1984). For this study, the adult and juvenile migration period was defined as December–May, based on hydrologic analysis of the Santa Maria River generally indicating mid-December through early May (Stillwater Sciences and Kear Groundwater, in preparation). A brief description of how the field measured habitat variables were calculated for inclusion in the model is provided in Table 5. Water temperature was not collected at every study site; therefore, water temperatures measured at nearby sites were used based on proximity and similarity of channel type.



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Table 5. Model variable calculation.

Variable Calculation

V1r Average max temp for July–August from thermographs deployed at Judell 14.2, Manzana 6.4 and 7.1, and Davy Brown 12.1

V1am Mean value of measured temperatures from December–May based on periodic daytime water temperature from the Sisquoc gage (1974, 1977–2011)

V2sm The mean value of measured temperatures from January–April based on periodic daytime water temperature from the Sisquoc gage (1974, 1977–2011)

V2inc The mean value of measured temperatures from January–May based on periodic daytime water temperature from the Sisquoc gage (1974, 1977–2011)

V3r DO reading taken at each site during the fall survey V3inc n/a V4 Thalweg depth averaged over all habitat units V5 Average velocity over spawning areas

V6a, V6j % instream cover averaged over all habitat units, collected in fall, used for both adults and juveniles

V7 Average spawning substrate size V8 % substrate 10-40cm, averaged over all habitat units V9 Predominant substrate type rating V10 Number of pools divided by the total number of habitats V11 Average % ground cover and canopy closure over all habitat units V12 Average % rooted vegetation and stable rocky ground cover over all habitat units V13 Minimum pH reading as recorded once per site, summer and fall V14 Estimated flow in fall divided by the estimated flow in summer as percent V15 Predominant rating over all pool habitat units V16sp Averaged over all spawning areas, data collected in summer V16rr Averaged over all riffle units, data collected in fall V17 Average % stream shading over all habitat units, collected in summer

V18 Ratio of average mean daily flow from November–May (adult migration period) to average annual flow at the Sisquoc gage (1945–1987)

4.3.2 Habitat suitability index curves

Field-measured habitat variables were used to calculate habitat suitability index scores for each model variable using HSI curves reported in Raleigh et al. (1984) or curves modified to account for conditions in central and southern California (TRPA 2004, 2011). The majority of habitat suitability index relationships are continuous (i.e., curves), with the exception of habitat variables V9 (average riffle substrate type) and V15 (pool class rating), which are categorical. The HSI curves from Raleigh et al. (1984) represent general habitat suitability relationships for O. mykiss, and do not necessarily capture adaptations of regional populations, and the authors encourage users to modify relationships when existing regional information indicates a different relationship better represents local conditions. The modifications to HSI curves used in this study are reported by TRPA (2011) in an assessment of O. mykiss habitat suitability in Arroyo Grande Creek, located about 10 mi to the north of the Santa Maria River. Because the TRPA (2011) study was not conducted specifically for anadromous O. mykiss life history forms, the modified HSI curve for steelhead smolt migration temperature (V2sm) used by TRPA (2004) for an assessment of steelhead habitat in Matilija Creek in Ventura County, was included in this study. The complete set of coordinates for HSI curves used in this study is presented in Appendix A.



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4.3.3 Model component and HSI scores

The HSI scores consist of five model component scores described by Raleigh et al. (1984) which are combined into a HSI score. For each study site, HSI scores were calculated using the equal component value method, which assigns equal weighting to each of the five model component scores (Raleigh et al. 1984). Study site scores represent reach-level habitat conditions for a given channel type. For sub-basin and watershed-wide HSI scores, the scores for study sites within similar channel types were averaged for a composite channel type score, and expanded using the weighted average of HSI scores over all channel types based on the percent occurrence by length of each channel type. These scores can be compared with other HSI scores from studies for O. mykiss performed in nearby watersheds.

5 RESULTS

5.1 Study Site Channel Types

Based on the drainage area and gradient criteria used in the site selection process (Section 3.2), each study sites is designated a representative channel type (Table 6).

Table 6. Study site channel type designations.

Study site Channel type and description Sisquoc 1.1 Manzana 3.5

Small, low gradient (SLG): <100 km2, 0–4% slope

Manzana 6.4 Manzana 7.1

Medium, low gradient (MLG): 100–250 km2, 0–4% slope

Sisquoc 5.3 Sisquoc 5.5

Large, low gradient (LLG): >250 km2, 0–4% slope

Sisquoc 10.1 Sisquoc 11.1 Davy Brown 12.1 Munch Creek 13.1 Judell 14.2 Judell 14.4

Small, high gradient (SHG): <100 km2, >4% slope

5.2 Study Site Habitat Types

The percent composition of Level-II habitat types at each study site is shown in Table 7. The total number of habitat units at a study site range from 10–24 units, and study site lengths range from 167–785 m. Riffle habitat is generally the most abundant habitat type at the study sites, with the exception of the small, low-gradient Sisquoc 1.1 and Manzana 3.5 study sites, where flatwater habitat predominates.



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Table 7. Habitat types and percent composition at study sites.

Pools Riffles Flatwater

Study site

Total no. of

habitat units

Total length

(m) Count Length

(m)

% of total

length Count

Length (m)

% of total

length Count

Length (m)

% of total

length

Sisquoc 1.1 20 263 8 89 33.8 6 78 29.7 6 96 36.5 Manzana 3.5 23 412 5 83 20.2 6 81 19.8 12 247 60.0 Manzana 6.4 21 565 6 122 21.5 9 236 41.7 6 208 36.8 Manzana 7.1 13 773 3 80 10.3 6 405 52.4 4 288 37.3 Sisquoc 5.3 10 785 3 150 19.1 4 437 55.7 3 197 25.1 Sisquoc 5.5 10 762 2 121 15.8 5 407 53.4 3 234 30.7 Sisquoc 10.1 17 167 4 32 18.9 8 90 53.6 5 46 27.5 Sisquoc 11.1 16 167 6 68 40.9 5 48 28.8 5 51 30.3 Davy Brown 12.1 22 246 6 48 19.7 10 143 58.0 6 55 22.3 Munch Creek 13.1 21 245 9 57 23.4 6 100 40.9 6 87 35.7 Judell 14.2 20 201 6 36 17.7 8 105 51.9 6 61 30.4 Judell 14.4 24 280 5 42 14.9 9 124 44.2 10 115 40.9

5.3 Water Temperature

Water-temperature data were recovered from four of the six water-temperature data loggers deployed. The data logger deployed at Sisquoc 1.1 was presumably lost as the result of a mud slide. The data logger at Sisquoc 5.3 was recovered, but the data were corrupted and could not be used. Water temperatures for the period from June through August range from 10.8–30.6°C (Table 8). The MWAT for all data loggers occurr in early July (Table 11). Daily minimum, maximum, and average water temperatures at each of the study sites with a temperature data logger are shown in Figure 5.

Table 8. Summer water temperatures (°C) at study sites with temperature data loggers.

Study site Mean Minimum Maximum MWAT MWAT week

(end date) Manzana 6.4 20.0 12.3 28.3 22.2 7/8/2011 Manzana 7.1 20.8 13.2 30.6 23.6 7/8/2011 Davy Brown 12.1 17.2 10.8 25.3 19.5 7/9/2011 Judell 14.2 18.5 12.9 25.7 20.5 7/9/2011



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Davy Brown 12.1

Judell 14.2

Figure 5. Daily minimum (green line), maximum (red line), and average (blue line) water

temperatures at study sites with temperature data loggers during June–August 2011.



18

Water temperature data from the data loggers were used to determine the average maximum water temperature for rearing (V1r) at each site based on proximity and similarity of channel type. Table 9 shows the average maximum water temperature in July–August used for habitat variable V1r, along with the corresponding sites where the temperature data were used. Table 9. Average daily maximum summer water temperatures (°C) during July–August at study

sites with temperature data loggers and corresponding HSI sites

Study site Average daily maximum

water temperature Corresponding HSI sites

Manzana 6.4 26.2 Manzana 3.5 Manzana 7.1 27.9 Sisquoc 5.3 and 5.5 Davy Brown 12.1 21.2 Munch Creek 13.1 Judell 14.2 21.9 Sisquoc 1.1, 10.1, 11.1 and Judell 14.4

Long-term periodic water temperature data from the Sisquoc gage show an average temperature of 14.8°C during the December–May time period used by the model for adult upstream migration (habitat variable V1am), 13.9°C during the January–April smolt migration period (habitat variable V2sm), and 15.2°C during the January–May embryo incubation period (habitat variable V2inc). Water temperature data from the Sisquoc gage used for habitat variables V1am, V2sm, and V2inc may be systematically lower than the “average maximum temperature” based on the variable description in Raleigh et al. (1984). However, temperatures at the study sites are likely to be cooler than those measured at the Sisquoc gage because they occur at higher elevations and generally have greater shading from riparian vegetation compared with conditions near the gage.

5.4 Habitat Variables

Habitat variable values measured during field surveys were compiled and average or representative values determined for each study site (Table 10). Habitat variable values derived from temperature and flow data obtained from the Sisquoc gage (V1am, V2sm, V2inc, V18) were applied equally to all sties. Habitat variable measurements at all study sites are compiled in Appendix B.



19

Table 10. Habitat variable measurements.

Channel type Small, low-

gradient Medium, low-

gradient Large, low-

gradient Small, high-gradient

Habitat variable Variable

code

Sis

qu

oc 1

.1

Man

zan

a 3.

5

Man

zan

a 6.

4

Man

zan

a 7.

1

Sis

qu

oc 5

.3

Sis

qu

oc 5

.5

Sis

qu

oc 1

0.1

Sis

qu

oc 1

1.1

Dav

y B

row

n 12

.1

Mu

nch

C

reek

13.

1

Jud

ell 1

4.2

Jud

ell 1

4.4

Max. rearing temp (°C) V1r 21.9 26.2 26.2 27.9 27.9 27.9 21.9 21.9 21.2 21.2 21.9 21.9 Max. adult migr. temp (°C) V1am 14.8 14.8 14.8 14.8 14.8 14.8 14.8 14.8 14.8 14.8 14.8 14.8 Max. smolt migr. temp (°C) V2sm 13.9 13.9 13.9 13.9 13.9 13.9 13.9 13.9 13.9 13.9 13.9 13.9 Max. Incubation temp (°C) V2inc 15.2 15.2 15.2 15.2 15.2 15.2 15.2 15.2 15.2 15.2 15.2 15.2 Min DO during rearing (mg/L) V3r 9.39 6.28 8.67 9.20 7.75 8.83 10.10 9.83 8.80 8.67 8.73 4.46 Min DO during incubation (mg/L) V3inc -- -- -- -- -- -- -- -- -- -- -- --

Avg. thalweg depth (cm) V4 30 24 26 21 17 15 16 33 15 25 15 10 Avg. spawning area vel. (cm/s) V5 34 38 47 38 56 55 49 25 -- 26 -- 27 Instream cover -juvenile (%) V6j 22.0 13.9 8.1 3.5 5.0 1.7 2.1 14.5 5.2 15.9 2.0 1.2 Instream cover -adult (%) V6a 22.0 13.9 8.1 3.5 5.0 1.7 2.1 14.5 5.2 15.9 2.0 1.2 Spawning substrate size (cm) V7 5.1 7.6 8.1 9.7 10.1 10.1 8.9 5.1 -- 9.3 -- 5.7 Winter substrate (%) V8 70.5 52.0 70.7 48.1 32.0 42.0 57.6 52.2 55.7 43.6 50.0 50.6 Avg. riffle substrate type rating V9 A A A B B B B A B A B B Pools (%) V10 33.8 21.2 21.5 10.3 19.1 15.8 18.9 37.5 19.7 23.4 17.7 14.9 Vegetation ratio V11 104 102 86 100 68 65 108 134 152 112 48 97 Bank cover (%) V12 91.0 87.4 82.6 59.2 22.5 39.0 84.7 93.8 77.1 94.5 59.3 50.8 Annual max/min pH V13 8.6 8.4 8.9 8.7 8.3 8.8 8.7 8.9 8.4 9.3 8.6 8.9 Base flow/avg. flow ratio V14 31.3 33.3 21.4 12.9 2.3 2.0 33.3 50.0 50.0 40.0 26.7 26.7 Pool class rating V15 C B C C C C C C C C C C Fines in spawning areas (%) V16sp 14.2 7.5 7.3 13.7 10.0 15.0 17.8 16.3 16.0 34.4 21.3 19.6 Fines in riffles and flatwaters (%) V16rr 31.7 5.8 8.3 8.7 6.7 20.0 73.7 41.7 19.5 15.0 37.5 63.3 Shade (%) V17 75.0 24.3 30.5 9.0 27.5 1.7 92.3 40.6 66.4 90.9 6.5 79.4 Migration flow/avg. flow ratio V18 165 165 165 165 165 165 165 165 165 165 165 165



20

5.5 HSI Scores

5.5.1 Individual habitat-variable scores

HSI scores were calculated for each habitat variable at each study site (Table 11). Scores ranged from 0.0 to 1.0 with a mean of 0.74, and a median of 0.81. HSI scores were relatively high at all study sties for variables associated with substrate size (V7 and V8) and adult migration flow ratio (V18). Small, low-gradient study sites (i.e., Sisquoc 1.1 and Manzana 3.5) generally scored higher for variables associated with instream and bank cover (V6a, V6j, V12) and percent fines (V16sp, V16rr) when compared with other study sites. Pool class rating (V15) was uniformly low over all study sites. Compiled reach-level and basin scores are discussed in Sections 4.1.4 and 4.2.1, respectively.



21

Table 11. Study site HSI scores

Channel type Small, low-

gradient Medium, low-

gradient Large, low-

gradient Small, high-gradient

HSI variable HSI

name

Sis

qu

oc 1

.1

Man

zan

a 3.

5

Man

zan

a 6.

4

Man

zan

a 7.

1

Sis

qu

oc 5

.3

Sis

qu

oc 5

.5

Sis

qu

oc 1

0.1

Sis

qu

oc 1

1.1

Dav

y B

row

n 12

.1

Mu

nch

Cre

ek

13.1

Jud

ell 1

4.2

Jud

ell 1

4.4

Max. rearing temp (°C) V1r 0.51 0.20 0.20 0.14 0.14 0.14 0.51 0.51 0.60 0.60 0.51 0.51 Max. adult migr. Temp (°C) V1am 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 Max. smolt migr. Temp (°C) V2sm 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 0.84 Max. incubation temp (°C) V2inc 0.72 0.72 0.72 0.72 0.72 0.72 0.72 0.72 0.72 0.72 0.72 0.72 Min. DO during rearing (mg/L) V3r 1.00 0.50 0.98 1.00 0.86 0.99 1.00 1.00 0.99 0.98 0.98 0.00 Min. DO during incubation (mg/L)

V3inc -- -- -- -- -- -- -- -- -- -- -- --

Avg. thalweg depth (cm) V4 1.00 0.94 0.97 0.81 0.62 0.48 0.57 1.00 0.52 0.95 0.52 0.18 Avg. spawning area vel. (cm/s) V5 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 -- 1.00 -- 1.00 Instream cover for juveniles (%) V6j 1.00 1.00 0.83 0.55 0.67 0.37 0.41 1.00 0.68 1.00 0.40 0.33 Instream cover for adults (%) V6a 0.98 0.81 0.60 0.40 0.47 0.30 0.33 0.82 0.48 0.86 0.33 0.28 Spawning substrate size (cm) V7 1.00 1.00 1.00 1.00 0.10 0.10 1.00 1.00 -- 1.00 -- 1.00 Winter substrate (%) V8 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 Avg. riffle substrate type V9 1.00 1.00 1.00 0.60 0.60 0.60 0.60 1.00 0.60 1.00 0.60 0.60 Pools (%) V10 1.00 0.74 0.77 0.52 0.71 0.64 0.71 1.00 0.73 0.81 0.68 0.62 Vegetation ratio V11 0.79 0.78 0.62 0.76 0.44 0.41 0.82 0.96 1.00 0.85 0.24 0.73 Bank cover (%) V12 1.00 1.00 1.00 0.86 0.33 0.54 1.00 1.00 1.00 1.00 0.86 0.73 Annual max./min. pH V13 0.58 0.80 0.14 0.44 0.88 0.29 0.44 0.14 0.80 0.00 0.58 0.14 Base flow/avg. flow ratio V14 0.63 0.67 0.43 0.26 0.05 0.04 0.67 1.00 1.00 0.80 0.53 0.53 Pool class rating V15 0.30 0.60 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 Fines in spawning areas (%) V16sp 0.78 0.98 0.98 0.80 0.95 0.74 0.61 0.68 0.69 0.18 0.44 0.52 Fines in riffles and flatwaters (%) V16rr 0.71 1.00 1.00 1.00 1.00 0.92 0.20 0.47 0.93 0.97 0.56 0.20 Shade (%) V17 1.00 0.64 0.73 0.43 0.69 0.32 1.00 0.87 1.00 1.00 0.39 1.00 Migration flow/avg. flow ratio V18 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00



22

5.5.2 Study site model component and channel type scores

Composite HSI scores for study sites ranged from 0.0 to 0.80, with a median of 0.62 (Table 12). A consistent juvenile component score of 0.50 was seen at all study sites except Manzana 3.5 (with a score of 0.81), and had the largest impact on both the site-level and overall channel type HSI scores. The low juvenile score is primarily influenced by the low pool class rating (C) found throughout the upper watershed, with pools generally less than 1 m deep. Three sites received HSI scores below 0.40, of which two were 0.0, and all three resulted from the “Other” model component score. These relatively low site scores strongly affect composite channel type scores, and the extrapolated sub-basin and basin-wide scores.

Table 12. HSI scores for model components at study sites and for channel types.

Study site Adult Juvenile Fry Embryo Other Study

site HSI

Channel type

Channel type HSI

Sisquoc 1.1 0.90 0.50 0.92 0.72 0.74 0.74

Manzana 3.5 0.90 0.81 0.86 0.72 0.71 0.80

Small, low

gradient 0.77

Manzana 6.4 0.84 0.50 0.88 0.72 0.59 0.69

Manzana 7.1 0.65 0.50 0.72 0.72 0.56 0.62

Medium, low

gradient 0.66

Sisquoc 5.3 0.78 0.50 0.85 0.46 0.44 0.58

Sisquoc 5.5 0.75 0.50 0.79 0.42 0.39 0.39

Large, low

gradient 0.49

Sisquoc 10.1 0.78 0.50 0.56 0.72 0.61 0.63 Sisquoc 11.1 0.89 0.50 0.83 0.72 0.68 0.71 Davy Brown 12.1 0.76 0.50 0.84 0.69 0.81 0.71 Munch Creek 13.1 0.88 0.50 0.89 0.56 0.00 0.00 Judell 14.2 0.76 0.50 0.72 0.44 0.48 0.56 Judell 14.4 0.55 0.50 0.53 0.72 0.00 0.00

Small, high

gradient 0.44

Small low-gradient channels (e.g., Sisquoc 1.1and Manzana 3.5) scored highest among all channel types (≥0.74). Study sites in this channel type had the highest HSI scores for all O. mykiss life stage components, and the highest overall site score of 0.80 at Manzana 3.5. The medium, low-gradient channel types (e.g., Manzana 6.4 and Manzana 7.1) had an overall channel HSI score of 0.66, and had lower scores for both the adult and “Other” components when compared with the small, low-gradient channels. The large, low-gradient channel HSI score was the second lowest, at 0.49, and had the lowest non-zero reach score of 0.39 at Sisquoc 5.5. It should be noted, however, that the Sisquoc 5.5 site score is influenced by a condition in the scoring methods: that the site score is equal to the lowest component score if any component score is ≤0.40. The small high-gradient channel HSI score is the lowest channel type score, at 0.44, and contains the lowest site scores of 0.00 at the Munch Creek 13.1 and Judell 14.4 sites. As described in the large, low-gradient channel scores, the zero scores at these sites are the result of constraints in the equation used to calculate a site score when any given component score is ≤0.40. Both these sites have a 0.00 component score for the “Other” component based on water quality measurements (see Table 12). The Judell 14.4 site score is the result of a low dissolved oxygen reading in



23

October that resulted in a suitability of 0.0. The Munch Creek 13.1 site score is the result of a maximum pH reading taken in June which also resulted in a suitability of 0.00. The anomalous DO reading at Judell 14.4 was carefully reviewed, ultimately considered valid, and therefore included in calculating the HSI score. The cause of the low DO reading is uncertain but believed to be the result of high nutrient load as evidenced by abundant algae growth; the source of which is assumed to be natural since little development or agricultural activity exists in the watershed. The pH reading at Munch Creek 13.1 is also considered a valid measurement based on readings collected at other sites. These two site scores have a substantial effect on the overall HSI score for this channel type, which is the most abundant channel type within the upper Sisquoc basin, and each of the three sub-basins.

5.5.3 Sub-basin and watershed-wide scores

Extrapolation of the channel type HSI scores to the length of channel within each type resulted in an upper watershed-wide HSI score of 0.55. HSI scores for Horse Creek, Manzana Creek, and upper Sisquoc sub-basins were 0.59, 0.59, and 0.53, respectively. As discussed above in Section 4.5 these scores are strongly influenced by the “Other” model component score, especially for Munch Creek 13.1 and Judell 14.4 sites in the SHG channel type. These HSI scores are discussed in more detail in Section 4.7.

5.6 Comparison with Other Watershed HSI Scores

The HSI scores for the three sub-basins in the upper Sisquoc River watershed were compared with HSI scores from nearby watersheds, building on the comparison reported in TRPA (2011) (Table 13 and Figure 6). The median reach-scale HSI score of these central and southern California watersheds is 0.71. The upper Sisquoc River Water and sub-basins all had scores below this median value. Only the small, low-gradient channel type in the upper Sisqouc River watershed scored above this regional average.



24

Table 13. Basin- or reach-scale HSI scores for the upper Sisquoc River and sub-basins, and other central and southern California watersheds reported in TRPA (2011).

Watershed Basin/reach name Basin ID1 HSI

score Model 2 Year

Upper Sisquoc River Upper Sisquoc River

(combined) - 0.55 STH 2011

Upper Sisquoc River Horse Creek - 0.59 STH 2011 Upper Sisquoc River Manzana Creek - 0.59 STH 2011 Upper Sisquoc River Sisquoc River - 0.53 STH 2011 Arroyo Grande Creek Lower Arroyo Grande Low Arroyo 0.71 RBT 2010 Arroyo Grande Creek Upper Arroyo Grande Up Arroyo 0.56 RBT 2010 Arroyo Grande Creek Lower Lopez Canyon Low Lopez 0.81 RBT 2010 Arroyo Grande Creek Middle Lopez Canyon Mid Lopez 0.79 RBT 2010 Arroyo Grande Creek Upper Lopez Canyon Up Lopez 0.81 RBT 2010 Arroyo Grande Creek Whittenberg Whittenberg 0.90 RBT 2010 Chorro Creek San Luisito San Luisito 0.82 STH 2006 Coon Creek Coon Coon 0.94 STH 2000 San Luis Obispo Creek Lower SLO Low SLO 0.34 STH 2000 Santa Clara River Pole Pole 0.68 STH 2010 Ventura River Lower NF Matilija Low LNF Low 0.73 STH 2003 Ventura River Lower NF Matilija Mid LNF Mid 0.74 STH 2007 Ventura River Lower NF Matilija New LNF New 0.76 STH 2007 Ventura River Lower NF Matilija Up LNF Up 0.78 RBT 2003 Ventura River Matilija 3 Mat 3 0.68 RBT 2007 Ventura River Matilija 5 Mat 5 0.69 RBT 2007 Ventura River Matilija 6 Mat 6 0.63 RBT 2003 Ventura River Matilija 7 Mat 7 0.71 RBT 2007 Ventura River Murrietta Murrietta 0.69 RBT 2003 Ventura River Old Man Old Man 0.64 RBT 2003 Ventura River San Antonio San Antonio 0.69 STH 2010 Ventura River Upper NF Matilija 2 UNF 2 0.74 RBT 2003 Ventura River Upper NF Matilija Low UNF Low 0.73 RBT 2003 Ventura River Upper NF Matilija New UNF New 0.82 RBT 2007 Ventura River Upper NF Matilija Up UNF Up 0.83 RBT 2003 Ventura River Ventura 1 Ven 1 0.63 STH 2007 Ventura River Ventura 2 Ven 2 0.69 STH 2007 Ventura River Ventura 3 Ven 3 0.67 STH 2007 Ventura River Ventura 5 Ven 5 0.65 STH 2007 Ventura River Ventura 6 Ven 6 0.51 STH 2003

1 From Table 6 in TRPA (2011). 2 STH indicates habitat variables and HSI curves for anadromous life history forms of O. mykiss were used where

available in the model, and RBT indicates that the habitat variables and HSI curves for resident forms of O. mykiss were used.



25

.34

.51.53

.56

.59 .59

.63 .63 .64 .65.67 .68 .68 .69 .69 .69 .69

.71 .71.73 .73 .74 .74

.76.78 .79

.81 .81 .82 .82 .83

.90

.94

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Low S

LOVen

6

Upper

Sisq

uoc

Up Arro

yo

Horse

Cre

ekM

anza

naM

at 6

Ven 1

Old M

anVen

5Ven

3PoleM

at 3

Mat

5M

urrie

ttaSan

Ant

onio

Ven 2

Low A

rroyo

Mat

7LN

F Low

UNF Low

LNF M

idUNF 2

LNF N

ewLN

F Up

Mid

Lope

zLo

w Lop

ezUp

Lope

zSan

Luis

itoUNF N

ewUNF U

pW

hitte

nber

gCoo

n

Figure 6. Channel type/reach-scale HSI scores for the upper Sisquoc River and other central and southern California watersheds (see Table 13

above for watershed reach descriptions).



26

6 DISCUSSION

6.1 Habitat Conditions

Results from this study should be considered a snapshot of aquatic habitat conditions for O. mykiss in the upper Sisquoc River watershed, and not necessarily representative of conditions over time. In fact, there is substantial evidence indicating that conditions within the upper Sisquoc River watershed are highly variable over time and substantially influenced by fires and floods. The Sisquoc River watershed lies in a fire-prone region of California. Fires, like floods, are stochastic events that significantly influence the quality and quantity of habitat available to O. mykiss life stages within the upper Sisquoc River watershed. The fire-flood cycle is likely the strongest determinant of habitat conditions for O. mykiss in this region. In the years immediately following fires, habitat conditions can degrade locally, primarily as a result of increased sediment supply, and floods can exacerbate the impacts. As vegetation recovers on hillslopes and within riparian corridors, sediment supply to stream channels is reduced, terrestrial cover and shade increase, and aquatic habitat conditions improve. During periods of recovery, moderate to high flows also function to remove coarse and fine sediment, scour pools, and maintain channel form and function. Fires are also spatially variable, such that different areas within a watershed are in different stages of impact and recovery at any one time. Therefore, some reaches can serve as refuge to O. mykiss while other heavily impacted reaches may take years or possibly even decades to fully recover. O. mykiss populations also show elasticity within these dynamic systems by straying into reaches that are degraded and/or in recovery, thereby expanding into available habitat as it becomes suitable, and building resiliency against future disturbance in the watershed.

6.1.1 Fire and flood frequency

Based on the historic record, four large fires (those burning over about 25% of the Sisquoc River watershed) occurred in the last 90 years, with the two most recent of these fires occurring in 2007 and 2009. Prior to 2007 it had been about 40 years since the last large fire, the Wellman fire, which occurred in 1966, and prior to that was the 1922 LaBrea fire. A moderately-large fire burned about 12.5% of the basin in 1955, and smaller fires (those burning <5% of the watershed) occured in about two out of every five years since 1940. Approximately nine large floods with peak discharge over 10,000 cfs occurred in the Sisquoc River basin since 1940, an average of about 1 every 7.5 years. Smaller floods on the order of 5,000–10,000 cfs occur more frequently, an average of about 1 every 5 years. An intense fire-flood sequence occurred in the upper Sisquoc River watershed over the past five years. In 2007, the Zaca fire occurred, burning much of Manzana Creek and upper portions of the Sisquoc River watershed. This fire was followed by a large flood in 2008, with a peak flow of 12,800 cfs at the USGS Sisquoc River near Garey gage (USGS 11140000). Another large fire occurred in 2009, primarily downstream of the Manzana Creek confluence in the Horse and LaBrea creek basins. This fire was followed by a flood in 2010 with a peak flow of about 9,440 cfs at the USGS Garey gage.



27

6.1.2 Effect of fires and floods on fish habitat

Fires in this dry chaparral-dominant region tend to be intense, consuming much of the available fuel and result in substantial loss of vegetative cover (intercepting precipitation) and root structure. This in-turn reduces soil strength and retention capacity on hillslopes. Once a fire has occurred, the hydrology in the burned area can be strongly affected for up to a decade, with a higher fraction of rainfall moving directly into stream channels as overland flow instead of being slowed by vegetation and infiltrated into the ground or evapotranspirated back into the atmosphere (Rulli and Rosso 2007, Cannon et al. 2008). In the years immediately following fires, sharp increases to the delivery of coarse and fine sediment to channels can result in the loss (burial) of pools and filling of interstitial spaces in coarse bed substrate. Fine sediment and ash from fires can embed spawning substrates and smother incubating eggs. Both of these effects are temporary, but for a period of a few years they can degrade the quality and decrease the extent of suitable spawning habitat until riparian vegetation re-establishes and/or fine sediment is flushed from the system. Surveys of the Sisquoc River watershed have documented impacts to O. mykiss spawning and incubation habitat as a result of fires (e.g., Shapovalov 1944, Titus et al. 2006, Love and Stoecker 2009, Stillwater Sciences 2012), but they have also documented subsequent recovery (Richardson 1959, Stoecker 2005). Surveys of available habitat and observations of multiple age classes of O. mykiss have concluded that suitable spawning habitat is abundant in the Sisquoc River watershed, including within the upper mainstem Sisquoc and South Fork Sisquoc rivers, and Manzana and Davey Brown creeks (Davis and Jackson ca 1934, Evans 1947, Douglas and Richardson 1959, Edwards et al. 1980, Kautzman and Uyehara 1999, and others, all as cited in Becker and Reining 2008; Shapovalov 1944; Cardenas 1996; Boughton and Fish 2003; Stoecker 2005). Results from this study indicate that spawning habitat has remained abundant. Stoecker (2005) reports pool depths frequently greater than 1 m, and commonly in the 1.5–2 m range, including reaches surveyed for this study. Observations by USDA Forest Service personnel indicate that deep pool habitat in portions of the upper Sisquoc River watershed present prior to 2007 was filled in 2010 (K. Cooper, USDA Forest Service, pers. comm., 2011). Pool-filling with fine sediment was also observed during the June and October 2011 surveys, in addition to mudslides near several of the study sites. Although this study recorded maximum pool depths generally less than 1 m, and resulted in low pool class ratings (C rating) at all sites, results did suggest that fine sediment was being flushed from some locations. Presuming no large fires occur in the next decade, hillslope and riparian conditions are expected to recover in those areas recently burned, and the quality and quantity of pool habitat in the upper Sisquoc River watershed is expected to improve as fine sediment is flushed from the system. O. mykiss are also expected to expand into impacted reaches as available habitat becomes suitable and improves over time. This is supported by observations of O. mykiss during the June and October 2011 surveys in fire-impacted reaches. Like any ecological study, the results should be considered within a relevant spatial and temporal context. For this study, the HSI model results appear to provide a reasonable relative measure of habitat conditions in the study area at the time of the surveys. However, considering available information, the upper Sisquoc River watershed is a dynamic system and aquatic habitat



28

conditions fluctuate widely, and the results of this study likely reflect the low-end of their range over time as a result of recent fires and floods in the basin.

6.2 HSI model sensitivity

The sensitivity of the HSI model results on the input parameters was briefly explored. In general, no one model parameter was found to have an overwhelming effect on model results. There were a few cases in this study, however, where changes in habitat variable measurements (some relatively minor) could have a meaningful affect on HSI scores. The pool class rating was found to have a relatively large impact on both the site-level and overall channel type HSI scores. Much of the sensitivity of this habitat variable is the result it having a categorical relationship. In this study, if sites had scored a higher pool class rating of B, indicating maximum pool depths of >1m on average, the resulting juvenile component score would increase from 0.50 to 0.81. The “Other” model component includes constraints in the equation used to calculate a site score when any given component score is ≤0.40. In some cases, particularly when a measured variable values is near this threshold, the constraint may have a meaningful effect. In this study, the “Other” component score at Sisquoc 5.5 was 0.39, just under the threshold. In this case, if the “Other” component score had been 0.41, then the site score would have increased form 0.39 to 0.55 and become more similar to the other large, low-gradient channel study site, Sisquoc 5.3. The resulting score for the overall channel type would have also increased from 0.49 to 0.57. HSI site scores for the Munch Creek 13.1 and Judell 14.4 sites, were strongly influenced by one water quality measurement resulting in the “Other” component score of 0.0. Omitting these study sites to test their effect on the results indicates the upper watershed-wide score would increase from 0.55 to 0.66. The effect of dry channels or intermittent channels on the upper watershed-wide score was also explored. Intermittent channels were observed at two of the study sites in the fall (Sisquoc 5.3 and Manzana 7.1). Omitting these study sites to test their effect on the results did not show a substantial effect (0.61 vs. 0.60). HSI scores reported for central and southern California watersheds in recent studies range from 0.34 to 0.94, with a median of 0.71 (Table 13, Figure 6). The upper Sisquoc River watershed and sub-basins all have scores below this median value. Only the small, low-gradient channel type in the upper Sisqouc River watershed scored above this regional average. Little information was identified on the precision of these scores, or the ability of this methodology to distinguish small differences between scores. Work conducted by TRPA (2008) found a statistically significant relationship with between reach level HSI scores and fish densities (r2=0.6–0.7).

6.3 Fish Observations

Trout (presumably O. mykiss) were observed during the June survey at most of the study sites, with the exception of those in the Sisquoc River near the Manzana Creek confluence (Sisquoc 5.3 and 5.5) and in Judell Creek (Judell 14.2 and 14.4). Observed trout ranged in size from 10–30 cm. No trout greater than 30 cm or obvious adult steelhead were observed. During the October survey, trout were observed at all sites previously observed during the June survey with the exception of Manzana 7.1 and the addition of Judell 14.2. Most trout were 15–30 cm, and no trout greater than 30 cm were observed. The trout observed in Manzana Creek



29

below Davy Brown Creek were found in isolated pools and appeared somewhat lethargic. Trout were observed at Judell 14.2 and Munch Creek 13.1, despite these sites having HSI scores of 0.0. These zero scores were both due to water quality measurements that resulted in a 0.0 score for the “Other” component used to calculate the site HSI. Additionally, in the intermittent pools of Manzana Creek and upper Sisquoc River, large numbers of small cyprinids, possibly speckled dace (Rhinichthys osculus), were observed.

7 LITERATURE CITED

Becker, G. S. and I. J. Reining. 2008. Steelhead/rainbow trout (Oncorhynchus mykiss) resources south of the Golden Gate, California. Cartography by D. A. Asbury. Prepared by the Center for Ecosystem Management and Restoration, Oakland, California for the California State Coastal Conservancy, Oakland, California and The Resources Legacy Fund Foundation. Boughton, D. A., and H. Fish. 2003. New data on steelhead distribution in southern and south-central California. National Marine Fisheries Service, Santa Cruz, California. Cannon, S. H., J. E. Gartner, R. C Wilson, J. C. Bowers, and J. L. Laber. 2008. Storm rainfall conditions for floods and debris flows from recently burned areas in southwestern Colorado and southern California. Geomorphology 96: 250–269. Cardenas, M. 1996. Upper Sisquoc River survey. California Department of Fish and Game. Davis, A. E. and H. C. Jackson. ca 1934. Sunset Valley Creek stream survey. Bureau of Fish Conservation, California Division of Fish and Game. Douglas, P. A. and W. M. Richardson. 1959. Survey of Sisquoc River. California Department of Fish and Game. Edwards, D., B. Philsinger, and K. Stater. 1980. South fork Sisquoc River stream survey, September 17. USDA Forest Service. Evans, W. A. 1947. Field notes, Alamo Creek. Bureau of Fish Conservation, California Division of Fish and Game. Flosi, G., S. Downie, J. Hopelain, M. Bird, R. Coey, and B. Collins. 1998. California salmonid stream habitat restoration manual. Third edition. California Department of Fish and Game, Sacramento. Kautzman, N. and J. C. Uyehara. 1999. Impact assessment and numbers of Oncorhynchus mykiss in streams of the Los Padres National Forest. USDA Forest Service. Love, M., and M. W. Stoecker. 2009. Fish passage assessment and recommended treatment options for Los Padres National Forest stream crossings on Davey Brown and Munch creeks. Prepared by Michael Love and Associates and Stoecker Ecological for South Coast Habitat Restoration, Earth Island Institute, and Los Padres National Forest. Montgomery, D. R., and J. M. Buffington. 1997. Channel-reach morphology in mountain drainage basins. Geological Society of America Bulletin 109: 596-611.



30

PRISM Climate Group. 2011. 103-year high-resolution temperature climate data set for the conterminous United States and United States average monthly or annual precipitation, 1971–2000. PRISM Climate Group, Oregon State University, Corvallis, Oregon. Raleigh, R. F., T. Hickman, R. C. Solomon, and P. C. Nelson. 1984. Habitat suitability information: Rainbow trout. FWS/OBS-82/10.60. U.S. Fish and Wildlife Service. Richardson, W. M. 1959. Survey of Sisquoc River, Santa Barbara County. Intraoffice correspondence. California Department of Fish and Game. Rulli, M. C., and R. Rosso. 2007. Hydrologic response of upland catchments to wildfires. Advances in Water Resources 30: 2,072–2,086. Shapovalov, L. 1944. Preliminary report on the fisheries of the Santa Maria River system, Santa Barbara, San Luis Obispo, and Ventura Counties, California. Bureau of Fish Conservation, California Division of Fish and Game. Shapovalov, L. 1945. Report on relation to maintenance of fish resources of proposed dams and diversions in Santa Barbara County, California. Bureau of Fish Conservation, California Division of Fish and Game. Stillwater Sciences. 2012 (in preparation). HSI study report. Technical memorandum. Prepared for the California Ocean Protection Council by Stillwater Sciences, Santa Barbara, California. Stillwater Sciences and Kear Groundwater. In preparation. Santa Maria River Instream Flow Study: flow recommendations for steelhead passage. Prepared by Stillwater Sciences and Kear Groundwater, Santa Barbara, California for California Ocean Protection Council, Oakland, California and California Department of Fish and Game, Sacramento, California. Stoecker, M. 2005. Sisquoc River steelhead trout population survey: fall 2005. Prepared by Stoecker Ecological, Santa Barbara, California for Community Environmental Council, Santa Barbara, California. Stoecker, M., J. Stoecker, and Community Environmental Council. 2003. Steelhead migration barrier assessment and recovery opportunities for the Sisquoc River, California. Prepared by M. Stoecker, J. Stoecker, and Community Environmental Council, Santa Barbara, California for California Coastal Conservancy, Oakland, California. Titus, R. G., D. C. Erman, and W. M. Snider. 2006. History and status of steelhead in California coastal drainages south of San Francisco Bay. In draft for publication as a Department of Fish and Game, Fish Bulletin. TRPA (Thomas R. Payne & Associates). 2004. Assessment of steelhead habitat quality in the Matilija Creek Basin. Stage two: quantitative stream survey. Report prepared for Public Works Agency and Ventura County Flood Control District, Ventura, California. TRPA (Thomas R. Payne & Associates). 2008. Steelhead population and habitat assessment in the Ventura River/Matilija Creek basin. Final Report. Report prepared for Public Works Agency and Ventura County Flood Control District, Ventura, California.



31

TRPA (Thomas R. Payne & Associates). 2011. Aquatic habitat suitability for Oncorhynchus mykiss in the upper Arroyo Grande basin, San Luis Obispo County, California. Prepared for Public Works Department, San Luis Obispo, California. USFWS (U.S. Fish and Wildlife Service). 2011. National Wild and Scenic Rivers: Sisquoc River. Website. http://www.rivers.gov/wsr-sisquoc.html [Accessed 30 November 2011]. Prepared by USFWS, Burbank, Washington.

Appendices

Appendix A

HSI Coordinates



A-1

Table A-1. Habitat suitability index curve coordinates used for habitat variables.

V1r HSI V1am HSI V2sm HSI V2inc HSI V3inc HSI V3r HSI 0 0.000 0 0.00 0 0.00 0 0.00 3 0.00 3 0.00 2 0.250 5 0.00 1 0.05 1 0.05 3.5 0.21 5 0.00 4 0.475 6 0.30 2 0.15 2 0.15 4 0.40 5.5 0.21 6 0.700 8 0.70 3 0.30 3 0.30 4.5 0.57 6 0.40 8 0.850 10 0.90 5 0.75 5 0.75 5 0.70 6.5 0.57 10 0.950 11 0.98 7 1.00 7 1.00 5.5 0.81 7 0.70 12 1.000 13 1.00 12 1.00 12 1.00 6 0.90 7.5 0.81 18 1.000 15 0.90 24 0.00 13 0.95 6.5 0.97 8 0.90 22 0.500 16 0.70 22 0.00 7 1.00 8.5 0.97 23.5 0.300 18 0.00 9 1.00 32 0.000 25 0.00 V4 HSI V5 HSI V6j HSI V6a HSI V7 HSI V8 HSI 8 0.00 0 0 0 0.20 0 0.200 0.00 0.00 0 0 10 0.15 10 0 2 0.40 2 0.325 0.25 0.22 10 1 12 0.30 20 1 4 0.60 4 0.425 0.50 0.43 80 1 14 0.44 60 1 6 0.73 6 0.510 0.75 0.64 16 0.56 100 0 8 0.83 8 0.600 1.00 0.80 18 0.68 10 0.90 10 0.680 1.25 0.95 20 0.78 12 0.96 12 0.750 1.50 1.00 22 0.86 14 1.00 14 0.810 10.00 1.00 24 0.93 16 0.860 10.10 0.10 26 0.97 18 0.910 28 0.99 20 0.950 30 1.00 22 0.980 24 1.000 V9 HSI V10 HSI V11 HSI V12 HSI V13 HSI V14 HSI A 1.0 0 0.30 0.0 0.05 0 0.20 5.0 0.00 0 0 B 0.6 30 0.95 25.0 0.10 10 0.24 5.5 0.00 50 1 C 0.3 32 0.98 50.0 0.25 20 0.30 6.0 0.65 100 1 34 1.00 75.0 0.51 30 0.40 6.3 0.96 64 1.00 87.5 0.64 40 0.55 6.4 1.00 68 0.98 100.0 0.76 50 0.72 8.1 1.00 100 0.50 112.5 0.85 60 0.87 8.2 0.96 125.0 0.92 70 0.98 8.4 0.80 137.5 0.98 75 1.00 8.6 0.58 150.0 1.00 9.0 0.00



A-2

V15 HSI V16sp HSI V16rr HSI V17 HSI V18 HSI A 1.0 0 1.00 0 1.00 0 0.3 0 0 B 0.6 5 1.00 12 1.00 50 1.0 25 0 C 0.3 8 0.98 20 0.92 110 1 10 0.95 30 0.75 12 0.88 40 0.50 20 0.50 50 0.30 25 0.25 60 0.20 30 0.20 60 0.06

Source Habitat variable Raleigh et al. 1984 V1am, V3r, V3inc, V4, V6j, V6a, V7, V9, V10, V11, V12, V13, V14, V15, V16sp, V16rr, V18 TRPA 2004 V2sm TRPA 2011 V1r, V2inc, V5, V8, V17

Appendix B

Habitat Variable Data



B-1

Table B-1. Habitat variable measurements at study sites. R

each

/Sit

e n

ame

Hab

itat

nu

mb

er

Hab

itat

typ

e—us

ed

to c

alcu

late

Poo

ls

(%)

Len

gth

(m

)

Wid

th (

m)

Sp

awn

pat

ch

nu

mb

er

Sp

awn

are

a (m

2)

Ave

rage

sp

awn

ing

area

vel

ocit

y (c

m/s

)

Sp

awn

ing

sub

stra

te

size

(cm

)

% s

ub

stra

te 1

0-40

cm

dia

met

er

Dom

inan

t su

bst

rate

ty

pe

in r

iffl

e/ru

n a

Veg

etat

ion

rat

io—

tree

s

Veg

etat

ion

rat

io—

shru

bs

Veg

etat

ion

rat

io—

gras

ses

Ban

k co

ver

(%)

Fin

es in

sp

awn

ing

area

s (%

)

Sh

ade

(%)

sum

mer

Fin

es in

rif

fles

an

d

flat

wat

ers

(%)

Sh

ade

(%)

fall

Ave

rage

th

alw

eg

dep

th (

cm)

Inst

ream

cov

er (

%)

Max

imu

m p

ool

dep

th (

m)

Poo

l cla

ss r

atin

g

(A, B

, C)

b

HSI Habitat variable

-- V10 -- -- -- -- V5 V7 V8 V9 V11 V11 V11 V12 V16 V17 V16 V17 V4 V6 -- V15

1 LSBK 16.8 4.9 30 90 10 0 100 100 70 76 50 1.5 B

2 HGR 18.9 4.0 90 A 70 20 0 90 10 80 50 80 24 10

3 PLP 11.6 5.2 60 100 0 0 100 100 70 37 15 0.6 C

4 POW 8.2 3.7 80 A 90 10 0 90 100 80 24 15

5 MCP 6.7 4.6 90 90 5 0 90 90 90 34 20 0.5 C

6 LGR 12.8 3.7 80 A 95 0 5 80 10 100 30 90 15 15

7 LSBO 7.6 3.7 60 90 0 5 90 80 70 37 30 0.5 C

8 HGR 13.7 3.0 90 A 90 0 0 100 5 90 30 80 18 30

9 DPL 12.5 4.6 20 100 0 0 70 100 70 43 35 0.8 B

10 CRP 7.0 4.3 30 90 0 0 100 70 80 30 20 0.5 C

11 PLP 11.6 4.0 40 90 0 0 100 80 90 46 30 0.7 B

12 STP 15.2 3.7 80 90 0 10 100 90 80 30 40 0.6 C

13 RUN 6.4 3.7 70 A 80 0 5 80 85 60 30 10

14 LGR 6.7 2.4 90 A 80 0 5 70 15 80 20 60 21 0

15 RUN 10.7 4.3 80 A 50 30 5 100 60 60 27 40

16 SRN 20.1 3.0 90 A 100 0 0 100 100 80 30 30

17 HGR 9.8 4.3 90 A 100 0 0 100 100 20 80 21 15

18 RUN 19.8 4.3 80 A 50 40 5 90 80 60 27 20

19 LGR 16.2 3.7 80 B 50 30 20 90 20 70 40 70 12 5

Sisquoc 1.1

20 RUN 30.8 4.6 1 1.1 34 5 80 B 90 10 0 80 25 75 80 18 10



B-2

Rea

ch/S

ite

nam

e

Hab

itat

nu

mb

er

Hab

itat

typ

e—us

ed

to c

alcu

late

Poo

ls

(%)

Len

gth

(m

)

Wid

th (

m)

Sp

awn

pat

ch

nu

mb

er

Sp

awn

are

a (m

2)

Ave

rage

sp

awn

ing

area

vel

ocit

y (c

m/s

)

Sp

awn

ing

sub

stra

te

size

(cm

)

% s

ub

stra

te 1

0-40

cm

dia

met

er

Dom

inan

t su

bst

rate

ty

pe

in r

iffl

e/ru

n a

Veg

etat

ion

rat

io—

tree

s

Veg

etat

ion

rat

io—

shru

bs

Veg

etat

ion

rat

io—

gras

ses

Ban

k co

ver

(%)

Fin

es in

sp

awn

ing

area

s (%

)

Sh

ade

(%)

sum

mer

Fin

es in

rif

fles

an

d

flat

wat

ers

(%)

Sh

ade

(%)

fall

Ave

rage

th

alw

eg

dep

th (

cm)

Inst

ream

cov

er (

%)

Max

imu

m p

ool

dep

th (

m)

Poo

l cla

ss r

atin

g

(A, B

, C)

b

1 LSBK 19.2 4.3 1 6.7 40 10 35 90 0 0 100 5 100 80 40 20 0.6 C

2 RUN 13.1 4.6 2 2.2 46 8 60 B 80 10 10 30 10 80 70 21 10

3 POW 13.4 4.6 75 A 80 5 10 100 90 70 21 10

4 LSBK 30.8 5.5 5 50 30 5 100 10 50 58 60 1.4 B

5 CAS 4.9 1.5 0 C 50 0 0 100 0 50 0 20 6 0

6 TRP 5.2 2.1 5 C 50 25 10 100 5 10 27 0 0.4 C

7 RUN 12.5 3.0 10 C 5 25 5 100 20 15 21 10

8 POW 50.6 3.7 80 A 30 20 10 90 20 25 18 15

9 RUN 14.3 4.6 70 B 60 20 0 80 25 15 18 5

10 LGR 16.8 4.6 80 A 70 20 10 100 30 10 20 15 5

11 LSBO 12.2 4.6 60 50 25 5 80 50 20 27 25 0.4 C

12 SRN 39.9 4.6 80 A 10 50 15 70 20 20 21 10

13 POW 22.6 4.6 90 A 10 30 5 80 15 20 15 5

14 RUN 9.8 3.7 50 B 15 20 5 80 10 20 24 20

15 LGR 9.4 4.3 90 A 5 40 5 90 5 20 10 20 18 5

16 GLD 21.9 4.0 3 1.9 37 5 15 B 20 20 10 80 15 35 15 27 15

17 LSBK 15.8 4.9 4 1.9 30 8 25 5 30 5 100 15 10 76 60 1.4 B

18 HGR 14.0 3.7 90 A 50 30 0 100 5 30 5 15 18 20

19 RUN 12.5 4.3 40 B 15 35 5 90 30 10 21 10

20 LGR 7.0 4.0 90 A 10 50 5 90 30 5 10 15 5

21 RUN 12.2 4.6 5 C 20 60 10 70 25 5 12 0

22 LGR 29.3 4.6 80 A 20 70 0 100 10 30 5 5 15 5

Manzana 3.5

23 RUN 24.4 4.3 5 2.2 37 8 60 B 50 40 0 80 10 60 15 18 5



B-3

Rea

ch/S

ite

nam

e

Hab

itat

nu

mb

er

Hab

itat

typ

e—us

ed

to c

alcu

late

Poo

ls

(%)

Len

gth

(m

)

Wid

th (

m)

Sp

awn

pat

ch

nu

mb

er

Sp

awn

are

a (m

2)

Ave

rage

sp

awn

ing

area

vel

ocit

y (c

m/s

)

Sp

awn

ing

sub

stra

te

size

(cm

)

% s

ub

stra

te 1

0-40

cm

dia

met

er

Dom

inan

t su

bst

rate

ty

pe

in r

iffl

e/ru

n a

Veg

etat

ion

rat

io—

tree

s

Veg

etat

ion

rat

io—

shru

bs

Veg

etat

ion

rat

io—

gras

ses

Ban

k co

ver

(%)

Fin

es in

sp

awn

ing

area

s (%

)

Sh

ade

(%)

sum

mer

Fin

es in

rif

fles

an

d

flat

wat

ers

(%)

Sh

ade

(%)

fall

Ave

rage

th

alw

eg

dep

th (

cm)

Inst

ream

cov

er (

%)

Max

imu

m p

ool

dep

th (

m)

Poo

l cla

ss r

atin

g

(A, B

, C)

b

1 LSR 14.9 4.3 95 100 0 0 100 100 80 40 40 0.7 B

2 LGR 9.1 3.7 100 A 95 0 0 100 0 100 10 80 18 5

3 RUN 19.5 4.3 95 A 100 0 0 100 100 70 21 10

4 HGR 14.9 3.7 95 A 95 5 0 100 5 100 5 70 15 0

5 LSBK 19.2 4.9 30 30 20 5 50 20 35 40 61 10 0.8 C

6 LGR 37.5 3.0 1 5.6 46 6 90 A 50 20 10 100 0 20 5 30 15 5

7 RUN 52.7 5.2 40 B 60 20 5 90 20 40 30 24 10

8 MCP 25.0 4.9 2 27.9 37 8 50 25 30 10 100 30 30 34 10 0.5 C

9 HGR 23.2 6.1 95 A 40 15 10 95 0 40 10 30 12 5

10 LSBK 21.6 5.5 40 30 20 10 60 10 35 20 46 5 0.9 C

11 LGR 31.4 4.9 3 7.4 49 9 95 A 5 60 0 70 0 15 10 10 12 0

12 RUN 37.2 4.6 50 B 20 20 5 70 20 10 24 10

13 LGR 45.4 4.3 95 A 15 30 0 100 0 15 10 15 9 0

14 LSBK 18.9 3.7 30 20 10 0 50 30 20 61 20 0.9 C

15 LGR 13.7 4.6 90 A 40 30 0 80 0 30 10 20 12 0

16 RUN 29.0 4.3 95 A 10 20 0 100 0 10 10 21 5

17 HGR 29.3 3.0 90 A 5 15 0 100 0 15 10 10 12 0

18 RUN 58.8 4.6 70 A 20 50 0 80 20 30 20 24 10

19 LGR 31.1 4.9 4 3.7 55 8 60 A 50 30 0 70 20 70 5 20 12 0

20 LSBK 21.9 3.7 5 5.6 49 10 20 5 30 0 80 15 50 15 49 20 0.8 C

Manzana 6.4

21 RUN 11.0 4.3 60 B 20 5 15 40 30 10 24 5



B-4

Rea

ch/S

ite

nam

e

Hab

itat

nu

mb

er

Hab

itat

typ

e—us

ed

to c

alcu

late

Poo

ls

(%)

Len

gth

(m

)

Wid

th (

m)

Sp

awn

pat

ch

nu

mb

er

Sp

awn

are

a (m

2)

Ave

rage

sp

awn

ing

area

vel

ocit

y (c

m/s

)

Sp

awn

ing

sub

stra

te

size

(cm

)

% s

ub

stra

te 1

0-40

cm

dia

met

er

Dom

inan

t su

bst

rate

ty

pe

in r

iffl

e/ru

n a

Veg

etat

ion

rat

io—

tree

s

Veg

etat

ion

rat

io—

shru

bs

Veg

etat

ion

rat

io—

gras

ses

Ban

k co

ver

(%)

Fin

es in

sp

awn

ing

area

s (%

)

Sh

ade

(%)

sum

mer

Fin

es in

rif

fles

an

d

flat

wat

ers

(%)

Sh

ade

(%)

fall

Ave

rage

th

alw

eg

dep

th (

cm)

Inst

ream

cov

er (

%)

Max

imu

m p

ool

dep

th (

m)

Poo

l cla

ss r

atin

g

(A, B

, C)

b

1 LGR 112.2 3.7 85 A 20 50 10 95 5 20

2 RUN 73.8 4.6 1 27.9 43 10 35 B 0 50 10 50 30 15 10 12 0

3 GLD 51.8 4.0 2 22.3 40 9 10 B 30 30 10 50 10 25 10 9 0

4 LSBK 27.4 4.3 5 15 10 0 60 10 5 49 5 0.7 C

5 HGR 29.6 6.1 95 A 0 60 10 70 0 20 10 10 9 0

6 LGR 39.9 9.1 30 B 0 50 0 30 20 5 15 5 6 0

7 GLD 85.0 8.2 3 55.7 30 10 0 B 40 30 10 5 30 40 10 21 5

8 LGR 77.7 6.1 80 B 20 40 5 50 5 15 5 5 9 0

9 LSBK 31.1 6.1 20 30 30 10 70 40 10 43 5 0.8 C

10 LGR 23.5 5.5 80 B 0 40 0 90 10 20 5 15 9 0

11 LSBO 21.3 4.9 50 5 20 5 100 15 10 40 20 0.9 C

12 LGR 122.2 3.0 75 A 5 70 5 60 40

Manzana 7.1

13 RUN 77.7 4.6 60 B 0 30 0 40 5

1 RUN 97.8 9.1 10 B 5 40 10 10 10

2 LSBK 54.3 6.1 5 5 40 0 50 15 30 10 0.5 C

3 LGR 76.5 7.6 80 B 20 5 0 0 5 15 5

4 RUN 60.0 6.1 60 B 0 20 0 0 0

5 LGR 86.9 7.6 50 B 5 5 0 5 10 5 10

6 RUN 39.3 6.1 30 B 0 5 0 0 5 10 6 0

7 LSR 17.1 5.5 5 60 10 0 20 50 30 21 5 0.4 C

8 LGR 71.9 9.1 1 13.9 61 10 60 B 10 70 0 40 5 20 5

9 LGR 202.1 7.6 10 C 70 10 10 50 30 20 9 0

Sisquoc 5.3

10 LSR 78.6 6.1 2 27.9 52 10 10 70 0 0 50 20 80 50 18 10 0.2 C



B-5

Rea

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Hab

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Hab

itat

typ

e—us

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to c

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Poo

ls

(%)

Len

gth

(m

)

Wid

th (

m)

Sp

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Sp

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Ave

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sp

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area

vel

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Sp

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size

(cm

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Dom

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Ban

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Fin

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sp

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area

s (%

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Sh

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(%)

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Fin

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d

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wat

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(%)

Sh

ade

(%)

fall

Ave

rage

th

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dep

th (

cm)

Inst

ream

cov

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%)

Max

imu

m p

ool

dep

th (

m)

Poo

l cla

ss r

atin

g

(A, B

, C)

b

1 MCP 82.0 9.1 5 0 5 5 35 0

2 LGR 73.2 10.7 40 B 0 30 10 10 10 0

3 RUN 93.6 7.6 1 18.6 55 10 15 B 0 50 10 50 10 5

4 LGR 54.6 12.2 20 B 30 40 10 70 25 20

5 RUN 86.6 9.1 15 B 0 50 5 50 5 0 9 0

6 HGR 42.4 6.1 90 A 0 5 0 50 0 0 20 0 6 0

7 RUN 54.3 7.6 60 A 0 10 0 25 0 0 12 0

8 LGR 53.3 9.1 60 B 0 5 0 40 20 0 20 0 9 0

9 LSBO 38.7 7.6 30 0 30 5 40 5 5 43 10 0.6 C

Sisquoc 5.5

10 LGR 183.8 9.1 85 A 0 50 5 20 25 5 20 5 9 0

1 RUN 8.2 2.4 80 A 90 10 0 90 100 100 21 5

2 LGR 8.5 2.1 90 A 100 0 0 70 15 100 90 100 12 0

3 LSBO 8.8 2.7 60 80 10 0 40 80 90 21 5 0.2 C

4 LGR 7.0 2.4 90 A 40 30 5 90 20 100 90 90 15 0

5 RUN 4.6 3.0 60 B 80 20 0 80 80 90 9 0

6 PLP 9.8 4.3 1 3.7 61 10 10 70 10 0 90 10 70 80 12 5 0.3 C

7 LGR 9.8 2.7 70 B 90 10 0 90 20 90 70 80 9 0

8 LSR 7.9 3.0 2 1.1 37 8 40 90 5 0 90 30 80 90 15 5 0.7 C

9 RUN 8.2 1.8 50 B 80 10 0 90 70 90 12 0

10 HGR 13.1 1.8 90 A 70 20 0 90 25 80 80 80 12 0

11 LGR 11.6 2.1 30 B 50 40 0 80 25 90 70 90 9 0

12 RUN 13.4 2.1 70 B 60 30 0 100 100 100 9 0

13 LGR 15.8 2.4 40 B 70 20 0 70 90 80 90 12 0

14 LSBO 5.2 3.0 70 80 20 0 90 100 100 46 5 0.6 C

15 HGR 20.4 1.8 60 B 90 10 0 100 5 100 70 100 18 0

16 RUN 11.6 3.0 20 C 100 0 0 80 100 100 24 10

Sisquoc 10.1

17 HGR 3.4 3.0 50 A 100 0 0 100 10 100 40 100 15 0



B-6

Rea

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Hab

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Len

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(m

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Wid

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(cm

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Max

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dep

th (

m)

Poo

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g

(A, B

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b

1 RUN 3.0 3.0 1 1.7 27 5 80 B 50 50 0 80 30 80 40 27 10

2 MCP 28.0 3.0 2 0.9 24 5 90 80 20 0 100 25 90 50 46 30 0.7 C

3 LGR 7.9 3.0 40 B 10 30 5 90 5 60 40 30 18 0

4 RUN 15.8 3.7 20 C 30 50 10 90 30 30 30 10

5 STP 10.4 4.3 10 C 50 30 0 100 60 20 43 15 0.6 C

6 RUN 13.1 3.7 80 A 10 60 0 100 50 30 24 10

7 HGR 3.4 2.4 80 A 5 70 0 100 5 70 20 50 18 0

8 RUN 10.4 4.0 60 B 30 40 10 80 70 50 37 10

9 LGR 20.1 3.0 85 A 60 30 0 80 20 50 70 40 21 10

10 HGR 11.0 4.3 20 C 60 30 0 100 5 30 50 40 21 0

11 MCP 6.1 4.6 20 40 50 0 90 30 30 37 15 0.6 C

12 POW 8.2 4.3 70 B 20 60 50 90 25 40 30 46 12

13 LSBO 5.2 3.7 40 20 30 0 100 15 30 61 40 1.0 B

14 LSBO 8.2 4.3 50 50 50 0 100 80 60 46 30 0.7 C

15 HGR 5.8 1.8 60 A 20 60 0 100 0 70 30 70 21 0

Sisquoc 11.1

16 PLP 10.4 4.6 3 1.9 24 5 30 30 70 0 100 40 60 50 37 40 0.7 C



B-7

Rea

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Hab

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Hab

itat

typ

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Poo

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(%)

Len

gth

(m

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Wid

th (

m)

Sp

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th (

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%)

Max

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m p

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dep

th (

m)

Poo

l cla

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g

(A, B

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b

1 LGR 7.3 2.1 25 C 50 40 10 80 30 90 30 80 9 0

2 MCP 4.0 1.8 50 40 60 0 75 80 90 21 5 0.3 C

3 HGR 9.4 1.5 80 A 60 30 10 60 20 80 10 70 9 0

4 MCP 6.1 1.8 50 50 40 10 60 80 80 21 5 0.4 C

5 RUN 10.7 2.1 60 B 30 70 0 60 70 60 18 5

6 HGR 6.7 3.0 20 C 10 60 30 100 10 30 10 30 9 0

7 LGR 22.9 1.5 60 A 40 50 10 70 20 40 20 70 9 0

8 RUN 11.0 2.1 25 B 30 50 20 20 30 30 12 5

9 LSBK 11.0 1.5 20 10 80 10 60 80 70 21 15 0.5 C

10 RUN 5.2 1.5 50 B 0 100 0 100 100 80 21 5

11 LGR 4.9 1.2 70 A 0 90 10 90 10 100 30 90 9 0

12 STP 12.8 1.8 10 20 70 10 100 90 90 21 5 0.3 C

13 LGR 11.3 2.1 80 A 60 30 10 100 10 60 20 80 9 0

14 RUN 5.8 2.7 60 B 60 20 20 60 80 60 18 0

15 LGR 19.2 1.8 70 B 80 20 0 90 20 80 30 60 9 0

16 RUN 13.7 2.1 80 B 60 20 20 50 40 50 18 5

17 LGR 9.8 1.8 90 B 40 40 20 100 10 20 20 40 12 0

18 TRP 7.6 1.8 75 20 60 20 60 15 40 30 30 0.5 C

19 LGR 20.7 1.8 70 B 20 70 10 90 20 40 10 60 12 5

20 RUN 8.5 1.8 60 B 80 10 10 90 100 70 15 0

21 LGR 30.5 1.5 70 A 80 10 10 80 10 100 15 70 9 10

Davy Brown 12.1

22 PLP 7.0 2.4 50 B 90 5 5 100 100 90 21 20 0.3 C



B-8

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Hab

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Hab

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Poo

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(%)

Len

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(m

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Wid

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m)

Sp

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(%)

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Ave

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dep

th (

cm)

Inst

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cov

er (

%)

Max

imu

m p

ool

dep

th (

m)

Poo

l cla

ss r

atin

g

(A, B

, C)

b

1 PLP 4.3 2.1 10 95 5 0 100 100 90 37 60 0.5 C

2 HGR 11.6 1.2 15 B 95 5 0 90 40 100 20 90 12 10

3 GLD 5.5 1.8 0 C 95 5 0 100 100 100 9 0

4 LSR 6.1 2.1 20 90 10 0 100 100 90 21 20 0.6 C

5 LSBo 4.9 1.8 35 70 30 0 100 100 100 34 30 0.7 C

6 PLP 3.7 1.5 70 85 10 5 100 100 90 30 20 0.4 C

7 RUN 3.7 1.8 85 A 90 10 0 100 100 90 18 0

8 PLP 5.2 1.5 90 95 5 0 100 100 90 21 5 0.4 C

9 SRN 14.3 1.8 75 A 90 10 0 100 100 90 18 5

10 LSBo 8.5 1.8 30 85 10 5 100 100 100 37 30 0.5 B

11 HGR 14.0 1.8 10 C 90 10 0 100 10 100 10 90 9 0

12 SRN 22.9 2.4 1 0.6 24 10 20 B 95 0 5 90 50 100 90 24 10

13 LGR 12.8 2.4 25 B 90 0 10 75 30 100 15 90 18 5

14 CRP 11.0 1.8 80 80 10 10 90 60 100 90 37 40 0.5 B

15 SRN 32.6 2.4 3 7.4 24 8 50 B 80 15 5 80 100 90 40 15

16 HGR 13.4 3.0 70 A 90 10 0 100 20 100 20 90 21 20

17 RUN 8.5 2.4 10 C 80 20 0 80 70 100 90 24 10

18 LSBO 9.1 2.4 30 B 70 15 15 100 100 90 43 30 0.6 C

19 HGR 16.8 2.1 70 A 70 15 15 100 10 100 10 90 18 10

20 LSBO 7.6 4.3 5 5 20 0 100 10 10 37 10 0.6 C

20 PLP 4.6 2.4 50 90 5 5 100 100 80 37 15 0.4 C

Munch Creek 13.1

21 LGR 31.7 2.4 70 A 80 5 15 80 20 100 15 90 12 0



B-9

Rea

ch/S

ite

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e

Hab

itat

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Hab

itat

typ

e—us

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to c

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Poo

ls

(%)

Len

gth

(m

)

Wid

th (

m)

Sp

awn

pat

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mb

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Sp

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2)

Ave

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Sp

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(cm

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stra

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Dom

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Veg

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Ban

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sp

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area

s (%

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(%)

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d

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wat

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(%)

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(%)

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Ave

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th

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eg

dep

th (

cm)

Inst

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cov

er (

%)

Max

imu

m p

ool

dep

th (

m)

Poo

l cla

ss r

atin

g

(A, B

, C)

b

1 RUN 6.1 1.8 20 B 0 10 0 70 0 0 18 5

2 PLP 4.3 2.1 70 0 5 0 80 0 0 15 5

3 HGR 10.1 1.5 80 B 0 10 0 70 20 0 30 0 9 0

4 LSBO 6.4 2.7 25 0 15 0 60 10 5 21 5 0.3 C

5 HGR 5.5 2.1 80 B 0 20 0 80 10 0 20 0 9 0

6 RUN 10.4 1.8 50 B 0 20 0 60 5 5 18 0

7 LGR 15.5 1.8 70 B 0 30 0 40 15 5 20 5 9 0

8 PLP 2.7 3.0 60 0 20 0 80 0 0 21 5 0.3 C

9 HGR 14.0 3.0 70 B 0 40 0 60 40 40 30 25 12 0

10 LSBO 6.4 6.1 20 0 50 0 80 50 30 24 5 0.5 C

11 LGR 13.7 1.8 80 B 0 10 0 50 20 5 20 5 9 0

12 RUN 12.8 2.1 50 B 0 50 0 25 10 10 15 0

13 LSBO 8.2 2.1 30 0 20 0 50 10 5 18 5 0.3 C

14 HGR 13.7 2.1 70 A 0 10 5 80 15 0 20 5 12 0

15 RUN 9.4 1.5 80 B 0 15 5 40 15 5 15 0

16 RUN 5.5 2.7 20 C 0 15 5 30 0 0 9 0

17 LGR 21.0 1.5 40 B 0 30 5 60 30 5 80 0 9 0

18 RUN 17.1 2.4 20 B 10 40 5 30 30 10 15 0

Judell 14.2

19 LGR 11.0 1.5 60 B 10 20 0 40 20 15 80 10 9 0



B-10

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Hab

itat

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Hab

itat

typ

e—us

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to c

alcu

late

Poo

ls

(%)

Len

gth

(m

)

Wid

th (

m)

Sp

awn

pat

ch

nu

mb

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Sp

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are

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Ave

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sp

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area

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)

Sp

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sub

stra

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size

(cm

)

% s

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stra

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dia

met

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Dom

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Veg

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Ban

k co

ver

(%)

Fin

es in

sp

awn

ing

area

s (%

)

Sh

ade

(%)

sum

mer

Fin

es in

rif

fles

an

d

flat

wat

ers

(%)

Sh

ade

(%)

fall

Ave

rage

th

alw

eg

dep

th (

cm)

Inst

ream

cov

er (

%)

Max

imu

m p

ool

dep

th (

m)

Poo

l cla

ss r

atin

g

(A, B

, C)

b

1 RUN 9.1 3.0 1 0.9 30 5 30 B 60 30 0 25 15 60 90 9 0

2 LGR 18.6 2.1 70 B 90 5 0 50 20 90 70 90 9 0

3 RUN 12.8 2.4 60 B 80 10 0 40 75 90 12 0

4 LGR 25.9 2.4 60 B 70 30 0 80 25 70 80 90 6 0

5 LSBK 11.0 1.8 70 90 10 0 85 80 80 9 0 0.2 C

6 RUN 12.8 13.7 2 0.5 27 8 50 B 90 10 0 70 25 90 80 9 0

7 PLP 7.3 3.0 3 3.9 24 5 20 90 5 0 80 25 90 90 15 5 0.3 C

8 LGR 7.6 1.5 40 B 70 10 0 40 15 80 70 80 9 0

9 RUN 11.0 2.1 30 B 80 0 0 20 70 80 12 0

10 LGR 6.1 2.1 50 B 30 20 0 90 20 50 70 70 9 0

11 RUN 12.2 2.1 40 B 50 40 0 30 70 90 6 0

12 RUN 22.6 1.8 40 B 80 5 0 70 90 90 15 10

13 HGR 7.6 2.7 70 B 60 20 0 40 20 80 60 90 9 0

14 RUN 9.1 2.4 30 B 60 25 0 20 70 90 9 0

15 LGR 19.5 3.0 30 B 90 5 0 60 15 90 70 100 6 0

16 RUN 7.9 1.8 20 B 90 0 0 20 90 80 9 0

17 LGR 22.9 2.4 60 B 100 0 0 25 20 100 60 90 9 0

18 RUN 5.2 1.8 50 B 100 0 0 30 100 90 6 0

19 PLP 5.2 2.1 60 70 20 0 25 100 70 15 5 0.3 C

20 LGR 10.7 1.8 40 B 5 40 0 10 20 5 60 15 9 0

21 LSBO 10.1 2.4 4 0.6 27 5 70 40 10 0 70 15 60 70 18 5 0.3 C

22 RUN 11.9 2.1 70 A 80 10 0 70 70 70 12 0

23 HGR 4.9 3.7 85 A 40 10 0 90 20 30 30 50 9 0

Judell 14.4

24 LSBK 8.2 3.0 70 50 20 0 80 60 70 15 5 0.3 C a Dominant substrate type in riffles: A= rubble and small boulders dominant; B=even mixture of rubble gravel, boulders, and fines, or gravel dominant; C= fines bedrock

or large boulder dominant. b Pool class rating: A= ≥30% of area is comprised of first-class pools (large and deep); B= 10–30% of area is comprised of first-class pools or ≥50% is comprised of

second-class pools (moderate size and depth); C= <10% of area is comprised of first-class pools or <50% is comprised of second-class pools (small or shallow or both).

habitat suitability for steelhead in the upper sisquoc river watershed

Documents