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

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

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

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

Pocomoke River and Sound Pocomoke Sound

Designated Use Shellfish growing

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

Example of observations

Seasonality Analysis

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

Water Quality Impairment Pocomoke River and Pocomoke Sound Fecal Coliform Statistics (MDE 2002-2005) Pocomoke River Fecal Coliform Statistics (VA-DEQ 2002-2005) * Stations located downstream of condemnation area

Landuse Distribution

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

Point Sources Maryland Virginia

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

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

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

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

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

Virginia Department of Health Field Survey

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

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)

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

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

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

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

Model Results

Load allocation and reduction by sub-watershed

TMDL Existing Loading TMDL

Load Reductions

Questions?