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

Tel. 512/239-4585

Pedernales River

Image by: Texas Water Development Board

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

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

• Comments from EPA 12/2/2010 letter

Lake Bridgeport

Image by: TRWD

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

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

Streams & Rivers: Challenges

Limited data for TN and relative abundance ofattached 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

Tx Streams: Instream Dilution

For 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%)

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

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)

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 tool

Left: Water Jets

Image by: CSTARS

Right: A Texas Estuary

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

EPA Framework for State Nutrient

Reductions: Eight Key Elements

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

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

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)

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?