Completed Projects: TMDL Projects
(jump to non-shellfish projects)
Shellfish TMDL Projects
In Virginia, most inshore tidal waters are identified as potential shellfish growing waters. There are currently about 235 shellfish growing areas that are condemned for shellfish harvesting due to elevated fecal coliform bacterial levels. Water quality monitoring of these waters indicate that levels of fecal coliform are above allowable, “safe” levels. Managers must identify the potential sources of pollution and devise plans to control them. The prescribed method for determining the pollution reductions needed to attain the water quality standard is the calculation of a total maximum daily load (TMDL). The TMDL is the amount of fecal coliform that may be introduced by each potential source without exceeding the water quality standard in shellfish growing waters. Requirements for TMDLs are found in the federal Clean Water Act and administered by EPA.
Development of TMDL models for Virginia Shellfish Growing Waters
PIs: Hershner, Mason, Herman, Kator, Shen
Funding Agency: Department of Environmental Quality
Period: 4/1/03 – 4/30/05
Amount: $294,496
The development of shellfish TMDLs for the condemned areas on the 1998 303d list of impaired water bodies in Virginia is a joint effort between the Virginia Institute of Marine Science, the Division of Shellfish Sanitation, and the Department of Environmental Quality. This project involves development of the databases and report formats for these models, and development of reports for half of the total number of areas.
The process of developing a shellfish water TMDL may be generalized in the following manner:
• Water quality monitoring data are used to determine if the bacterial standard for shellfish have been violated;
• Potential sources within the contributing watershed are identified;
• The necessary reductions in pollutant load to achieve the water quality standard are determined;
• The TMDL study is presented to the public to garner comment;
• An implementation plan is developed and implemented;
• Water quality monitoring data are used to determine if the bacterial standard is being met for shellfish waters.
Watersheds with shellfish TMDLs currently under development include:
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Rappahannock River: Mud and Parrotts Creeks
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Lagrange and Robinson Creeks
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Urbanna Creek
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Whiting and Meachim Creeks
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Broad and Jackson Creeks
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Piankatank River, Lower
See the following DEQ website for other TMDL reports:
http://www.deq.state.va.us/tmdl/
Development of a GIS Database in Support of Virginia's Shellfish Sanitation Program
PIs: Berman
Funding Agency: VA Department of Health, Department of Conservation and Recreation
Period: 2/11/02– 3/31/03
Amount: (F) $100,000 + (M/VDH) $12,489 = $112,489
This project provides technical support in the development of a GIS database for the Division of Shellfish Sanitation at the Virginia Department of Health. This Division collects and maintains a vast amount of water quality data relevant to point and non-point source pollution that will be required for TMDL modeling. This effort converts the DSS hardcopy products to digital formats and provides the division with an extensive archive of existing data. In addition, the project provides technical support in the acquisition and use of GPS equipment for data collection in the field.
Characterization of Shellfish TMDL Sites
PIs: Hershner, Kator
Funding Agency: Department of Environmental Quality
Period: 7/1/02 - 6/30/02
Amount: $320,900
Water quality monitoring of these waters indicate that fecal coliform exceeds the specified total maximum daily load (TMDL) more than 10% of the time. EPA standards require TMDL models for these waters. This project collected available information related to watershed characteristics, such as land use, elevation data, soil permeability, failed septic systems, and potential sources of pollution. The objective was to categorize the growing areas according to the suite of site description parameters amassed in the data base, using cluster analysis. Since the development of TMDLs will be costly and on a very short timeline, the goal was to group similar sites in an effort to reduce model development requirements.
Click here to view the final report.
TMDL Projects - Dissolved Oxygen
Seasonal Monitoring, Fecal Coliform Loads,
Lynnhaven River System
PIs: Hershner
Funding Agency: Virginia Beach
Period: 11/1/05-3/31/07
Amount: $53,259
A collecting and sampling program was
developed for fecal coliform following runoff
events in the Lynnhaven River System. This
information will be used to support water quality
and TMDL modeling.
Completed Projects: Development of DO TMDL for Onancock Creek
PIs: Shen, Herman, Mason
Funding Agency: Department of Environmental Quality
Period: 11/1/03 – 7/1/05
Amount: $62,812
Low dissolved oxygen (DO) is often observed in eutrophic waters that receive excessive nutrients and organic matter. DO levels below state water quality standards require the development of a total maximum daily load (TMDL) to determine the reductions needed to meet the water quality standard. The North Branch of Onancock Creek, located on the Eastern Shore of the Chesapeake Bay, is impaired for DO. This project involves the development of a 3-D
hydrodynamic and water quality model to determine various scenarios for source allocations between point and nonpoint sources.
Link to Final Report
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