TMDL Development for the Floyds Fork Watershed

Louisville, KY

August 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 which

takes 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?