Chowan River TMDL Development and Source Assessment Tidewater Area October 20, 2004

Watershed

TMDL Steps – Tidewater Monitoring/Listing - Identification of Water Quality Problem. Source Assessment – Locating potential contributors of pollutant in watershed. Modeling – Examining the movement of sources from the land to the water. Allocation/TMDL – Use the model to determine the load reductions necessary to achieve water quality goals.

Historical Water Quality Data Analysis Fecal Coliform Concentrations ImpairmentStation Sampled Dates Count (#) Minimum (cfu/100ml) Maximum (cfu/100ml) Mean (cfu/100ml) Median (cfu/100ml) Violation (%) 1,000 Violation (%) 400 Milldam Creek5BMLD /95-3/ , Nawney Creek5BNWN /93-3/ , Nawney Creek5BNWN /93-3/ , West Neck Creek5BWNC /85-5/ , West Neck Creek5BWNc /91-5/ , West Neck Creek5BWNC /72-5/ , West Neck Creek5BWNC /95-3/ , London Bridge Creek 7LOB /97-8/ ,6001,1671,

Water Quality Data Analysis During TMDL Development ImpairmentStation Sampled Dates Count (#) Minimum (cfu/100ml) Maximum (cfu/100ml) Mean (cfu/100ml) Median (cfu/100ml) Violation (%) 235 Milldam Creek5BMLD /02- 3/ Nawney Creek5BNWN /02- 3/ Nawney Creek5BNWN /02- 3/ West Neck Creek5BWNC /02- 5/ West Neck Creek5BWNC /02- 5/

Enterococci Data ImpairmentStation Count (#) Minimum (cfu/100ml) Maximum (cfu/100ml) Mean (cfu/100ml) Median (cfu/100ml) Violation 1 (%) Nawney Creek5BNWN , West Neck Creek (Upper)5BWNC , London Bridge Creek 7LOB , Violations based on Enterococci instantaneous standard (i.e., 104 cfu/100 ml)

Source Assessment Livestock Wildlife Pets Permitted discharges Wastewater treatment facilities Human Biosolids

Permitted Discharges Chlorine  fecal coliform translator Historical averages (DMR) for calibration period Design values for allocations Direct application

Permitted Discharges

ImpairmentPermit IDTypeFacilityComment West Neck Creek (Upper)VA IndustrialUS Naval Air Station Oceana West Neck Creek (Upper)VA IndustrialUS Naval Air Station Oceana London Bridge CreekVA IndustrialUS Naval Air Station Oceana West Neck Creek (Upper)VA IndustrialUS Naval Air Station Oceana London Bridge CreekVA IndustrialUS Naval Air Station Oceana London Bridge CreekVA IndustrialUS Naval Air Station Oceana West Neck Creek (Upper)VA NR-012IndustrialUS Naval Air Station OceanaStorm Water Outfall Nawney CreekVPG150001CAFOBarry Knight Hog FarmNow owned by Back Bay NWF West Neck Creek and London Bridge Creek VAR040043MS4 Exact location unknown

Human Source Population, housing units, and onsite treatment system based on U.S. Census Sanitary Sewer Loading rates  Exfiltration  Overflows Land-applied / direct deposition  Loading type  Proximity to stream

Human Source Septic Systems Failure to soil surface throughout year Lateral movement continuously to stream Straight Pipes Direct continuous input into stream Biosolids Land-applied

Human Source

Human Source (2004) ImpairmentPopulation Housing Units (HU) HU with Sewer HU with Septic HU with Other Milldam Creek Nawney Creek West Neck Creek (Upper) 29,5499,7489, West Neck Creek (Middle) 4,4311, London Bridge Creek 42,58515,35815, TOTAL 77,41926,94425,0861,83227

Pet Source Population/household based on literature values, veterinarians, and animal control Translated to housing units based on U.S. Census Land-applied

Pet Source (2004) ImpairmentDogsCats Milldam Creek 3034 Nawney Creek West Neck Creek (Upper) 5,2055,829 West Neck Creek (Middle) London Bridge Creek 8,2019,184 Total 14,38716,112

Livestock Source Distribution of waste Pastured Confined, waste collected, spread Direct deposition to the stream Seasonal varying applications Population Virginia Agricultural Statistics Consultation with SWCD, NRCS, VADCR, and VCE Watershed visits

Livestock Population (2002) Impairment All Cattle BeefDairyHogsHorseSheep Milldam Creek Nawney Creek West Neck Creek (Upper) West Neck Creek (Middle) London Bridge Creek Total

Wildlife Source Population Animal densities from VDGIF biologists Habitat from literature values Distribution of waste based on habitat Land-applied Direct deposition to the stream Seasonal variations based on migration patterns and food sources

Wildlife Population ImpairmentDeerGooseDuckMuskratRaccoonBeaverSeagull Milldam Creek Nawney Creek West Neck Creek (Upper) West Neck Creek (Middle) London Bridge Creek Total ,4271,

Bacterial Source Tracking Antibiotic Resistance Analysis (ARA) Differentiates the sources of bacteria based on bacterial resistance to antibiotics

Bacterial Source Tracking Results WaterbodyStation Human (%) Pet (%) Livestock (%) Wildlife (%) Milldam Creek 5BMLD Nawney Creek 5BNWN West Neck Creek 5BWNC

Modeling

Hydrologic model Runoff model HSPF Water Quality model Tidal/Estuary model CE-QUAL-W2 Model Calibration and Validation Based on data availability, period of interest

Modeling

Pets Biosolids Application VPDES Permit Conceptual Model Mathematical Representation Withdrawal Direct discharges Overland Wildlife on the Land Pastured Livestock Lateral Flow from Septic Systems Parking Lots Wildlife in Stream Livestock in Stream Septic Failures Sewer Overflows Straight Pipes

Hydrologic Modeling Components Climatic data Land use Topography Soils Stream channel characteristics Point source discharge/withdrawal Flow data

Land use

ImpairmentAcres Forest (%) Barren (%) Agricultural (%) Urban (%) Water (%) Milldam Creek 2, Nawney Creek 4, West Neck Creek (Upper) 11, West Neck Creek (Middle) 7, London Bridge Creek 5, TOTAL31,394

Water Quality Modeling Components Sources Fecal production FC densities FC distribution Delivery Mechanisms Direct Land-applied Temporal Variation

Public Meeting 2 (Date?) Public Meeting 3 (Date?) Public Review Submit to EPA State Approval Implementation Plan Development Implementation

Hydrologic Calibration