1. Total Maximum Daily Loads of Fecal Coliform for the Restricted Shellfish Harvesting/Growing Areas of the Pocomoke River in the Lower Pocomoke River Basin and Pocomoke Sound Basin in Somerset and Worcester Counties, Maryland and Accomack County, Virginia
Public Meeting
July 23, 2008

2. Why We Are Here To present water quality status of impairment sites
To explain the process of development of Total Maximum Daily Load (TMDL)
To gather comments and encourage public participation

3. The TMDL Process
DEQ routinely monitors the quality of waters statewide and publishes a list of impaired waters every 2 years
Virginia is required by federal law to establish a TMDL for each pollutant causing an impairment
A TMDL is the amount of a particular pollutant that a stream can receive and still meet Water Quality Standards
Aquatic life
Fishing
Shellfishing
Drinking water
Wildlife
Recreation
Designated Uses
Water Quality Standards
Water Quality Criteria

4. TMDL=WLA+LA+MOS Where TMDL=Total Maximum Daily Load
WLA=Waste Load Allocation (point sources)
LA=Load Allocation (nonpoint sources)
MOS=Margin of Safety

5. Pocomoke River and Sound
Pocomoke Sound

6. Designated Use
Shellfish growing

7. Observation
Observations have been conducted by both MDE and Virginia Department of Health - Division of Shellfish Sanitation for more than 10 years

8. Example of observations

9. Seasonality Analysis

10. Water Quality Standards
Maryland:
Approved classification means that the median fecal coliform MPN of at least 30 water sample results taken over a 3-year period to incorporate inter-annual variability does not exceed 14 per 100 milliliters; and:
The 90th percentile of water sample results does not exceed an MPN of 43 per 100 milliliters for a five tube decimal dilution test or 49 MPN per 100 milliliters for a three tube decimal dilution test
Virginia:
The geometric mean fecal coliform value for a sampling station shall not exceed an MPN (most probable number) of 14 per 100 milliliters. The 90th percentile shall not exceed an MPN of 43 for a 5 tube, 3 dilution test or 49 for a 3 tube, 3 dilution test

11. Water Quality Impairment
Pocomoke River and Pocomoke Sound Fecal Coliform Statistics (MDE )
Pocomoke River Fecal Coliform Statistics (VA-DEQ )
* Stations located downstream of condemnation area

12. Landuse Distribution

13. What Are Fecal Coliform and E. coli Bacteria?
Coliform Bacteria: Common in soil, decaying vegetation, animal feces, and raw surface water
Fecal Coliform: Found in the digestive tract of humans and warm blooded animals; Indicator of the potential presence of pathogens in water bodies
E. coli: Subset of fecal coliform; Correlate better with swimming associated illness

14. Point Sources
Maryland
Virginia

15. Potential Source: Human Contribution
Household waste
Onsite Treatment System
Public Sewer
Straight Pipes
Failing System
Pump out
Treatment Plant
Land Application
Biosolids
Effluent
Runoff
Stream

16. Potential Source: Wildlife Contribution
Pasture
Cropland
Forest
Urban
Built-up area
Runoff
Stream

17. Potential Source: Livestock Contribution
Confinement
Direct Accessing
Manure Storage
Pasture
Manure Spreading
Cropland
Runoff
Stream

18. Potential Source: Pets Contribution
Pasture
Cropland
Forest
Urban
Built-up area
Runoff
Stream

19. Source Assessment Field survey
Bacteria Source Tracking (BST) Data Analysis
BST: Uses Antibiotic Resistance Analysis for source load allocation (4 categories)
Human
Pets
Livestock
Wildlife

20. Virginia Department of Health Field Survey

21. BST Results
Monthly Distribution of BST Data Analysis Results at Maryland Stations
Monthly Distribution of BST Data Analysis Results at Virginia Stations

22. BST Results Source Distribution Based on BST Data Analysis (MDE)
Source Distribution Based on BST Data Analysis (DEQ)
Weighted Average Source Distribution Based on MDE and VA-DEQ BST Data Analysis (Exclude unknown category in MDE’s BST Data)

23. Modeling Approach
Use 3-dimensional model to simulate bacteria transport and fate in estuary
Simulate
Tide
Salinity
Estuarine circulation
Bacteria concentration
Use observation data and model to estimate bacteria loading from sub-watershed
Delineate watershed into sub-watershed
Use inverse method to estimate loadings

24. Model Grid and Sub-watershed Segmentation
Discharge from watershed
(flow/bacteria loading)
Model simulation
Tide
Salinity
Bacteria concentration
Tidal forcing

25. Model Simulation of Tide and Salinity
Comparison of modeled and NOAA predicted mean tidal range

26. Inverse Load Estimation
Freshwater from sub-watersheds
Observations
Tide
Salinity
Model-data comparison
Based on the best fit
Estuary
(Simulated by 3D model)
Loading from sub-watershed …
SWS1
SWS2
SWS19
SWS20
Satisfactory No
Adjust loading for each sub-watershed
Yes
End

27. Model Results

28. Load allocation and reduction by sub-watershed

29. TMDL
Existing Loading
TMDL

30. Load Reductions

31. Questions?