Nutrient Criteria for Streams and Rivers


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Nutrient Criteria for Streams and Rivers EPA Framework for Nutrient Reduction

Texas Water Conservation Association
Water Quality Subcommittee
October 13, 2011

Jim Davenport
WQ Monitoring & Assessment Section
WQ Planning Division Office of Water, TCEQ

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Nutrient Criteria for Streams and Rivers

  1. 1. Nutrient Criteria for Streams and Rivers EPA Framework for Nutrient ReductionTexas Water Conservation AssociationWater Quality SubcommitteeOctober 13, 2011Jim DavenportWQ Monitoring & Assessment SectionWQ Planning DivisionOffice of Water, TCEQ Pedernales River Image by: Texas Water Development BoardTel. 512/239-4585
  2. 2. TCEQ Nutrient Criteria: Development Submitted plans to EPA in 2001, 2006 Reservoirs, then streams & estuaries Convened advisory workgroup Based on data for each reservoir Proposed for 93 reservoirs - Stand-alone Chl a criteria - Chl a criteria, + screening levels: TP, transparency Adopted for Chl a for 75 reservoirs, 6/30/10
  3. 3. EPA Review WQ Standards • Adopted by TCEQ - 6/30/2010 • Additional documentation to EPA - 8/4/2011 • EPA request for more information regarding nutrient criteria - 5/17/2011 Standards Implementation Procedures • Approved by TCEQ 6/30/2010 Lake Bridgeport Image by: TRWD • Comments from EPA 12/2/2010 letter
  4. 4. Summary of Current Plans Develop criteria option for selected rivers and estuaries based on historical conditions - Individual water bodies - Reference groupings Develop criteria option for streams and rivers based on stressor/response analyses Initiate additional options for estuaries based on ongoing efforts (e.g., stressor/response) Revisit reservoir criteria Consider ways to incorporate weight-of-evidence Develop implementation options
  5. 5. Why Are Nutrient Criteria Difficult? Lack of clear “use-based” thresholds for uses such as recreation & aesthetics, aquatic life propagation, drinking water sources Responses to nutrients are highly variable – e.g., effect of TN and TP on Chl a No consensus on how to derive criteria Independent criteria or “weight-of evidence”? Insufficiencies in historical monitoring data Initial EPA guidance criteria were problematic High concern about regulatory impacts
  6. 6. Streams & Rivers: Challenges Limited data for TN and relative abundance of attached algae Regional, hydrologic, chemical variability Grouping streams and rivers Parameters? TP, TN, Chl a, % cover … Weight-of-evidence – Development, Assessment Effluent-dominated streams / attainability Reasonable implementation
  7. 7. Tx Streams: Instream DilutionFor 358 major domestic discharges:% effluent instream at 7Q2 No. of discharges 0 - 25% 57 (16%) 26 - 50% 32 ( 9%) 51 - 75% 47 (13%) 76 - 99% 122 (34%) 100% 100 (28%)
  8. 8. Available Data – Streams and Rivers 30-40 years of data at 100’s of stations, for TP, ~TN, Chl a, Transparency, D.O., etc. plus frequent fish, invertebrate sampling Data and Research Needs • Algae Sampling – attached periphyton sampling • Representative Stations • More TN data • Lower TP and TN detection limits Recent Stream and River Projects • Regional nutrient sampling studies of streams • Statistical responses to N & P – historical data • Peer review of other states, prognosis for Texas • Additional studies
  9. 9. The Road Ahead: Streams & Rivers Categorize and group based on  Geography?  Hydrology?  Chemical similarities? Option 1: Base criteria on historical levels in reference streams and rivers Option 2: Stressor/response analyses, relating TN,TP to biological indices, D.O., Chl a (in rivers), attached algae (smaller streams)
  10. 10. EPA Framework for State Nutrient Reductions  EPA Memo from Nancy Stoner, 3/16/2011  Summarizes 8 key elements needed for state programs to reduce nutrient loadings  Intended as a flexible planning toolLeft: Water JetsImage by: CSTARSRight: A Texas Estuary
  11. 11. EPA Framework for State Nutrient Reductions: Eight Key Elements Prioritize watersheds on a statewide basis Set watershed load reduction goals Ensure effectiveness of point source permits Agricultural areas Storm water and septic systems Accountability and verification measures Annual public reporting of implementation activities & biannual reporting of load reductions Develop work plan, schedule for numeric criteria
  12. 12. Recent Activities 3/10/11 EPA (Jackson) addresses U.S. House Committee on Ag, re: nutrient criteria 3/16/11 EPA memo on nutrient framework 5/24/11 EPA VI requests responses to memo 6/23/11 ASIWPCA letter, urging flexibility for framework, “weight-of-evidence” for criteria 8/23/11 TCEQ provides initial response to memo 10/4/11 U.S. Senate subcommittee on nutrients 10/5/11 States meet with EPA on flexibility & weight of evidence for nutrient criteria
  13. 13. EPA Nutrient Framework Initial TCEQ Response (8/23/11) TCEQ is already implementing many elements: - Reservoir nutrient criteria, continuing efforts - New standards implementation procedures - Watershed efforts by TCEQ and TSSWCB - Increased studies, monitoring efforts Resource/regulatory impact concerns - Texas has ~ 210 8-digit HUC watersheds TCEQ amenable to discussion with EPA
  14. 14. 2010 Nutrient Implementation Procedures In 2010 Standards Implementation Procedures Applied to increases in domestic discharges Sets framework for nutrient (TP) effluent limits Reservoirs – predict effects on “main pool” Reservoirs – assess local impacts - Apply site-specific screening factors - Level of concern – low, moderate, or high - Assess “weight-of-evidence” Streams – assess local impacts (as for reservoirs)
  15. 15. Nutrient Criteria & Management Concluding Notes• EPA review of 2010 nutrient criteria continues• Focus of options for stream nutrient criteria: - Historical reference conditions - Observed responses to N & P (existing data) - Incorporating “weight of evidence” - Flexibility for implementation• Discussions on EPA framework are pending• Questions / Comments?