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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?
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