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