Developing Developing Nutrient Criteria Nutrient Criteria for Reservoirs: for Reservoirs:
How it May Impact How it May Impact You You
J. Warren Schlechte and John B. Taylor - Inland Fisheries
Patricia L. Radloff – Coastal FisheriesTexas Parks and Wildlife Department
OutlineOutline
Background/History Current Approaches
in TX Current Approaches
across the South Future
BackgroundBackground
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
BackgroundBackground
Ecology of Cultural Eutrophication Results
Increased productivity Shifts in species composition Low DO and death
www.saltonsea.ca.gov/ltnav/current.html
BackgroundBackground
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 soEPA steps in
BackgroundBackground
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
BackgroundBackground
EPA Requirements Nutrient over-enrichment
Nitrogen and Phosphorous are causal agents Chlorophyll-a is measurable response
variable
Divide US in 14 ecoregions
BackgroundBackground EPA Approach
75th percentile of pristine waters 25th percentile of all waters
E P A S u g g e s t e d M e t r i c s
2 3 .5
4 3 .5
0
0 .0 1
0 .0 2
0 .0 3
0 .0 4
0 .0 5
0 .0 6
0 .0 7
0 .0 8
0 .0 9
0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0
T o t a l P h o s p h o r o u s ( u g / L )
Lik
eli
ho
od
Current - TXCurrent - TX
Three approaches Use-based Anti-degradation Approach
Parametric, based on all historic data Nonparametric, based on recent historic
data
Current - TXCurrent - TX
Use-based Proposal
Visit reservoirs in summer Survey users (min. 7) Collect WQ data concurrently Correlate user survey with WQ
Current - TXCurrent - 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)
Current - TXCurrent - TX
Anti-degradation Approach Parametric
Proposal Look at Chlorophyll-a Uses all historic data, outliers eliminated Focuses on “reference reservoirs” Uses 99th percentile of CI of mean
Current - TXCurrent - 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
Current - TXCurrent - 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 90th percentile of raw data For degraded reservoirs
Similar reservoirs Historic record when not degraded Statewide 85th percentile
Current - TXCurrent - 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
Current – Other StatesCurrent – 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
Current – Other StatesCurrent – 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
Ramifications for Ramifications for FisheriesFisheries
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
Next StepsNext Steps
Rivers and Streams in ???? Estuaries in ????
Get Involved
AcknowledgmentsAcknowledgments
Texas Parks and Wildlife – Inland Fisheries
Sportfish Restoration