Least Disturbed StreamsStephen Curtis, TPWD River Studies

Lauren Pulliam, SWQM Central OfficeRob Cook, EPA Region 6

CWA Section 101 - ObjectiveTo restore & maintain the:

● Chemical ● Physical ● Biological integrityof the nation's waters

Comprehensive information about the biological integrity of aquatic environments needed to:

• complement the established perceptions of physical and chemical integrity

• provide a complete picture of the ecological integrity of the nation's waters.

Section 303 (c) 2 (B):…where numeric criteria are not available, States shall adopt criteria based on biological assessment methods…

Ohio comparison of biosurvey with chemical evaluation

6%

36% 58%

Chemical prediction & biosurvey agree

Chemical evaluation indicates no impairment

Biosurvey shows impairment

Biosurvey showsno impairment

Chemical evaluation indicates impairment

Value of biological information

3

4

• What we are measuring is what we are trying to protect

• More precisely define and measure aquatic life goals

• Better assess current and potential conditions

• Quantify progress towards meeting aquatic life goals

• More effectively communicate the health of the waters to the public

Value of biological information

Strengthen Water Management Programs

Demonstrate environmental outcomes

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Why this works – basic concept

Exposure to Stressors

Biol

ogic

al C

ondi

tion

With increased human disturbance, we see the following widespread changes:

Sensitive organisms: Organisms that are sensitive to pollution are likely to die (esp. sessile).

Tolerant organisms: Organisms that are tolerant to pollution become more abundant.

Diversity: A decrease in the number of species.

Dominance: One or few kinds of organisms make up a large portion of the total.

Where to start?

• Stoddard et al. 2006 defines four types of reference conditions:• Minimally disturbed condition – condition of systems in the absence of

significant human disturbance (e.g. low level atmospheric contaminants only)

• Best attainable condition – condition that today’s sites might achieve if they were better managed

• Historical condition – condition at some point in the past (e.g. pre-intensive agriculture, pre-settlement)

• Least disturbed condition – best of today’s existing conditions (based on a set of explicit criteria defining what is “best”, which vary across regions and time)

Stoddard, J.L., Larsen, D.P., Hawkins, C.P., Johnson, R.K. and Norris, R.H., 2006. Setting expectations for the ecological condition of streams: the concept of reference condition. Ecological Applications, 16(4), pp.1267-1276.

Reference Streams

Factors considered - reference sitesUpstream, Upstream, Upstream and Instream, too• Impoundments, NPDES dischargers, spills or pollution incidents,

human density, agriculture activity, road/highway density, minimal non-point source problems, etc. Instream habitat, flow regime, etc.

Classification• To group similar things together to prevent comparison of apples to

oranges• Reduce the complexity of biological information• Improve resolution or sensitivity of biological surveys to detect impairment

(by accounting for variability among sites) ECOREGIONS

History of the Texas LDS Project• 1989 TX Water Commission publication, An

Assessment of Six Least Disturbed Unclassified Texas Streams

• “Minor water bodies have historically been grouped into a single category (unclassified waters) and provided limited protection under the general criteria of the TSWQS.”

• Of the six streams studied: 1 exceptional ALU, 4 high ALU, 1 limited ALU

History of the Texas LDS Project• 1992 TX Water Commission, TPWD, and EPA Region 6

publication, Texas Aquatic Ecoregion Project: An Assessment of Least Disturbed Streams

• Goals of the project:• Determine if significant aquatic life uses existed in small

unclassified streams• Determine if regional patterns in physical, chemical, or biological

attributes exist• Define and verify TX Ecoregions• Develop procedures for assessing aquatic life uses in Texas streams

Current LDS Project Goals• Compile all data on LDS ecoregion reference streams

• Evaluate historical LDS sites to determine if still suitable

• Evaluate candidate LDS sites to determine if they should be added to the LDS database

• Field sampling in 60-75 historical and/or candidate LDS site• Sampling complete at ~50 sites

• Sample a subset of streams more than once to provide data that meets temporal requirements of an Aquatic Life Monitoring event

Least Disturbed Ecoregion Reference Streams…

• Have little or no urban development in the watershed

• Have no major point sources of pollution

• Have no atypical sources of non-point source pollution

• Are not channelized, or have not had major physical habitat modifications

Benthic Macroinvertebrate Collection Methods

• Historical methods:• Riffles with 1 ft2 surber

sampler • Ekman grab samples of

soft bottom substrate at sites with no riffles

• Collected three replicates per site

• Mean Point Score

• Current methods:• 5 minute kicknet - RBP• Snag sampling at sites

with no riffles• Minimum of ~200

individuals collected• Index of Biotic Integrity

ER 33/35 Benthic IBI Calibration Using LDS Data

• Taxa and Composition Measures• Functional Composition• Tolerance Measures

Determine scoring criteria range for each metric using raw data percentiles

ER 33/35 Benthic IBI Calibration Using LDS Data

Physical Habitat Data Collection Methods

• Historical methods:• Watershed area and stream gradient• Flow• Instream and riparian characteristics at 5 transects along 0.5 to 1.0 km reach

• Stream width and depth• Instream cover• Substrate composition• Tree canopy• Stream bank slope, stability, vegetative cover

• Current methods:• Instream and riparian characteristics at 5-6 transects along 150-500 m reach

Fish Collection Methods• SWQM Procedures, Volume II

• Seining: minimum of 6 effective hauls• Electrofishing: minimum of 900 seconds• All available habitat within study reach• Field/lab processed specimens

Fish: Regionalized IBI AssessmentCatfish Creek @ Engling WMA, Anderson Co.Collector: Kleinsasser & Crowe August-88Metric Category Intermediate Totals for Metrics Metric Name Raw Value IBI Score

Drainage Basin Size (km2) 554Number of Fish Species 24 Number of Fish Species 24 5Number of Native Cyprinid Species 5 Number of Native Cyprinid Species 5 5Number of Benthic Invertivore Species 5 Number of Benthic Invertivore Species 5 5Number of Sunfish Species 6 Number of Sunfish Species 6 5Number of Intolerant Species 2 Number of Intolerant Species 2 3Number of Individuals as Tolerantsa 14 % of Individuals as Tolerant Speciesa 7.4 5Number of Individuals as Omnivores 4 % of Individuals as Omnivores 2.1 5Number of Individuals as Invertivores 167 % of Individuals as Invertivores 88.8 5Number of Individuals as Piscivores 17 % of Individuals as Piscivores 9.0 3Number of Individuals (Seine) 128 Number of Individuals in Sample 3Number of Individuals (Shock) 60 Number of Individuals/seine haul 14.2 3Number of Individuals in Sample 188 Number of Individuals/min electrofishing 3.85 3# of Individuals as Non-native species 0 % of Individuals as Non-native Species 0.0 5# of Individuals With Disease/Anomaly 3 % of Individuals With Disease/Anomaly 1.6 1

Index of Biotic Integrity Numeric Score: 50Aquatic Life Use: High

a Excluding Western MosquitofishThis data should be incorporated with water quality, habitat, and other available biological data to assign an overall stream score.

Ecoregions 33 & 35

Species Richness and Composition

Trophic Composition

Fish Abundance and Condition

• Calculated an IBI for each sampling event –> 7 regionalized IBIs• Compare overall IBI scores• Assess and refine individual metrics

Linam et al. 2002

Fish: Status of Reference Streams

IMPROVING

DEGRADING

Supplemental Data Analysis

• GIS Data• Land-Use Land-Cover• Point/NP Sources• Instream Barriers

• Multivariate Analyses• Benthic Macroinvertebrates• Fish Community

• Microplastics

mdpi.com

Future Plans

• A lot left to do…• Supplemental field sampling• Sample processing• Data analysis• Report writing

• Least Disturbed Streams Report• Tentative due date: August 2018• Committee meeting – develop an outline & action items

Thank You!!