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Developing Nutrient Criteria for Reservoirs: How it May Impact You J. Warren Schlechte and John B. Taylor - Inland Fisheries Patricia L. Radloff – Coastal.

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Presentation on theme: "Developing Nutrient Criteria for Reservoirs: How it May Impact You J. Warren Schlechte and John B. Taylor - Inland Fisheries Patricia L. Radloff – Coastal."— Presentation transcript:

1 Developing Nutrient Criteria for Reservoirs: How it May Impact You J. Warren Schlechte and John B. Taylor - Inland Fisheries Patricia L. Radloff – Coastal Fisheries Texas Parks and Wildlife Department

2 Outline Background/History Current Approaches in TX Current Approaches across the South Future

3 Background Ecology of Cultural Eutrophication Nutrients Introduced into System Point source and Non-point source Flow important Source: http://www.unep.or.jp/ietc/publications/short_series/lakereservoirs-3

4 Background Ecology of Cultural Eutrophication Results Increased productivity Shifts in species composition Low DO and death www.saltonsea.ca.gov/ltnav/current.html

5 Background Clean Water Act (1972) Cornerstone of surface water quality/integrity Aims to reduce pollutants into our waterways State must catalog waters and designate uses Establish WQ standards If states fail to do so EPA steps in

6 Background Current Parties Involved Drinking water purveyors (surface water) Wastewater dischargers Lakeside homeowners, recreationalists, environmentalists Fish and aquatic inhabitants Why Should You Care? If you don’t participate, your views ignored

7 Background EPA Requirements Nutrient over-enrichment Nitrogen and Phosphorous are causal agents Chlorophyll-a is measurable response variable Divide US in 14 ecoregions

8 Background EPA Approach 75 th percentile of pristine waters 25 th percentile of all waters

9 Current - TX Three approaches Use-based Anti-degradation Approach Parametric, based on all historic data Nonparametric, based on recent historic data

10 Current - TX Use-based Proposal Visit reservoirs in summer Survey users (min. 7) Collect WQ data concurrently Correlate user survey with WQ

11 Current - TX Use-based Pros Familiar Specifically addresses the recreational uses for the water and seeks to protect those uses Cons Typically, data vague or non-existent Metrics coarse Weight uses (recreational, drinking, aquatic)

12 Current - TX Anti-degradation Approach Parametric Proposal Look at Chlorophyll-a Uses all historic data, outliers eliminated Focuses on “reference reservoirs” Uses 99 th percentile of CI of mean

13 Current - TX Parametric Pros Numerical data exist and criteria measurable Cons Assumed distribution may not fit Only looking at chlorophyll-a Only focusing on subset of reservoirs No plan for reservoirs without data

14 Current - TX Anti-degradation Approach Nonparametric Proposal Look at Ortho-P, Nitrite/Nitrate and Chlorophyll-a, Uses last 10 years historic data for non-degraded reservoirs Uses 90 th percentile of raw data For degraded reservoirs Similar reservoirs Historic record when not degraded Statewide 85 th percentile

15 Current - TX Nonparametric Pros Uses actual data Criteria definable and measurable Deals with lack of data and degraded issues Causal and Response Variables Cons Single threshold, and in tail region Tends to pick up acute changes in nutrients

16 Current – Other States Tennessee Site specific, Nitrate/Nitrite and Total Phosphorous Arkansas ??, Chlorophyll-a, possibly others Alabama Site specific, Chlorophyll-a Mississippi Reference condition, chlorophyll-a

17 Current – Other States Florida Regional, Combination causal and response Georgia Site specific, Combination causal and response New Mexico Ecoregions, systems, TN, TP, Chlorophyll-a Oklahoma Site specific, Chlorophyll-a, P and/or N

18 Ramifications for Fisheries Excessive Nutrients Excessive Macrophytes Golden and Blue-green Algae Anoxia and pH Shifts Stress and Disease Invasive Species Limited ability to fertilize Anglers are not only user group

19 Next Steps Rivers and Streams in ???? Estuaries in ???? Get Involved

20 Acknowledgments Texas Parks and Wildlife – Inland Fisheries Sportfish Restoration


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