TMDL Development for the Floyds Fork Watershed

Louisville, KYAugust 30, 2011

Presenters

• Paulette Akers KY Division of Water• Chris Thomas Chief -- Pollution Control and

Implementation Branch• Tim Wool National TMDL Expert

Water Quality Modeler, TOM• Brian Watson Director, Water Resources Group

Tetra Tech, Atlanta

Opening Remarks• Background

– Segments of the Floyds Fork Watershed are on Kentucky’s 303(d) list for: Nutrients (organic enrichment), Dissolved Oxygen & Pathogens

– At KY’s Request EPA Started to Develop Nutrient TMDL in 2007

– EPA Receives Notice of Intent in 2011• Contract awarded to Tetra Tech for the development of watershed

and water quality models to be used in a TMDL determination• Period of Performance: May 2011 – November 15, 2012• Cost: $419,050

TMDL Process

Clean Water Act Section 303(d)

Each State shall establish . . . The total maximum daily load. . .at a level necessary to implement the applicable water quality standards with seasonal variations and a margin of safety whichtakes into any lack of knowledge…………

TMDL Process• Problem Statement

– Floyds Fork is listed for: Nutrients and Dissolved Oxygen• Definition of Endpoint

– WQS• Dissolved Oxygen: Daily Average 5 mg/L no Less than 4 mg/L• Nutrients: In lakes and reservoirs and their tributaries, and other

surface waters where eutrophication problems may exist, nitrogen, phosphorus, carbon, and contributing trace element discharges shall be limited in accordance with:

– The scope of the problem;– The geography of the affected area; and– Relative contributions from existing and proposed sources.– Source Identification

TMDL Process– Point Source Dischargers– MS4 Dischargers– Non Point Sources

• Linkage Between Sources and Receiving Water• Allocation

TMDLs

Overall Allocation Formula:

MOSLAWLATMDL

Where:

WLA is the Sum of Waste Loads (Point Source + MS4)

LA is the Sum of Loads (Nonpoint Source)MOS is the Margin of Safety

Stakeholder Process

Stakeholder Process• Lessons Learned• You are a Valuable Resource

– Site Specific Knowledge– Engaged in the Process– Have Individual Concerns

• Regulatory Decision Making Process– Proposal– Final

Working Together

• EPA will use a stakeholder process in the development of the TMDL – Status of the Model Development will be presented at

future meetings– Models will be made available for outside technical

review– We encourage your involvement

Approach

TMDL Approach• TMDL will be developed to meet the designated

uses and applicable water quality standards• TMDL will address

– Current loading conditions– Determine reductions needed to meet TMDL Condition– Allocate to:

• Point Sources• Point Source – MS4• Non Point Sources

Models to be Used

• Watershed Model– Loading Simulation Program C++

• Water Quality Model– Water Quality Analysis Simulation Program (WASP)

• Both Models have been extensively used for TMDL Development

• Both Models have been peer reviewed• Proven track record of linking these models

together

Watershed Model -- Background• Visual C++ programming has seamless integration

with Microsoft Access and Excel• Same algorithms as HSPF• Simulates watershed hydrology and water quality

dynamically• Land use and rainfall based• Outputs flows and concentrations for receiving water

model (WASP)

Water Quality Model -- Background• Water quality model• Dynamic• Full Eutrophication Kinetics• Parameters simulated

– DO– BOD– Ammonia– Nitrate-Nitrite– Organic Nitrogen– Organic Phosphorus– Ortho Phosphorus– Chlorophyll a

Modeling Approach• Calibrate and Validate to current conditions (2000

– 2010)• TMDL Reduction Scenarios

– Determine the load reduction required to meet Water Quality Standards

– Provide initial wasteload & load allocations

• Implementation– Modeling framework can be used to pollutant sharing

and re-allocation

Data Review

Location Map

Elevation (Source: USGS National Elevation Dataset (NED), 1/3 Arc-Second)

Land Use (Source: 2006 National Land Cover Database (NLCD), Pervious)

Land Use (Source: 2006 National Land Cover Database (NLCD), Impervious)

Soils (Source: SSURGO)

Geology (Source: Kentucky Geography Network – kygeonet.ky.gov)

Karst Areas (Source: Kentucky Geography Network – kygeonet.ky.gov)

Point Sources (Source: KDOW and EPAR4)

Sampling Stations (Source: USGS, KDOW, MSD, and WBPs)

Meteorological Stations (Source: National Climatic Data Center (NCDC, USGS)

Septic Systems

Next Steps

• Evaluate any new data• Setup the watershed model• Calibrate/validate the watershed model• Next stakeholder meeting

– November 2011• Present watershed model calibration• Present water quality endpoints

Questions?