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Chowan River TMDL Development Tidewater Area 08/26/04

Chowan River TMDL Development Tidewater Area 08/26/04. Historical data analysis Source assessment Bacterial source tracking Modeling Allocation. TMDL Development. Fecal Coliform Impairments. Impaired Stream Segments in the Back Bay and North Landing River watersheds.

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Chowan River TMDL Development Tidewater Area 08/26/04

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  1. Chowan River TMDL Development Tidewater Area 08/26/04

  2. Historical data analysis Source assessment Bacterial source tracking Modeling Allocation TMDL Development

  3. Fecal Coliform Impairments Impaired Stream Segments in the Back Bay and North Landing River watersheds

  4. Water Quality Data Analysis Location of VADEQ water quality monitoring stations in the Back Bay and North Landing River watersheds

  5. Water Quality Data Analysis Fecal Coliform Concentrations

  6. Water Quality Data Analysis E. coli concentrations for period July 2002 through March 2004

  7. Water Quality Data Analysis • Statistical Analysis of Water Quality Measurements versus Precipitation to determine the relationship between rainfall and water quality • Summary of the Mood Median Test on mean monthly precipitation at station 444101 (p=0.013).

  8. Source Assessment • Identification of Sources • DEQ/DCR/Locality records • Ag Census • Habitat Analysis • Stakeholders, local knowledge • BST • Source Characterization • Fecal production / densities / distribution • Delivery Mechanisms • Direct • Land-applied • Exported Out of Watershed • Temporal Variation

  9. Two permitted dischargers – one in West Neck, one in Nawney Creek. Only one is currently active. Permitted Discharges * Farm no longer active

  10. Human (2004)

  11. Sanitary sewer Overflows - reported to DEQ Exfiltration – rate from literature Failing septic systems Rate based on age of house Straight pipes U.S. Census and VDH consultation Human

  12. Reported Sewer Overflows • Frequent overflows in West Neck Creek Drainage. • 55 events reported between July 1999 and May 2004. • Uncertainty as to whether all overflows are reported/observed. • Mean overflow volume of 109 gallons.

  13. Pets (2004)

  14. Estimated Livestock - 1997

  15. Estimated Livestock - 2002

  16. Livestock Average percentage of collected livestock waste applied throughout year

  17. Wildlife Population

  18. Wildlife

  19. Source Assessment

  20. Bacterial Source Tracking Location of BST stations in the Back Bay and North Landing River watersheds

  21. 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

  22. Modeling

  23. Modeling

  24. Modeling VADEQ Station 5BWNC010.02 and USGS Station #02043200

  25. Modeling VADEQ Station 5BMLD001.92 and USGS Station #02043200

  26. Modeling VADEQ Station 5BNWN001.84 and USGS Station #02043200

  27. Modeling VADEQ Station 5BNWN000.00 and USGS Station #02043200

  28. Hydrologic CalibrationSample

  29. Hydrologic CalibrationSample

  30. Develop reduction scenarios that will meet water quality standards 100% reduction in straight pipes, 25% reduction in failed septic systems 100% reduction in straight pipes, 50% reduction in livestock direct deposition Allocate loads to each source Allocation

  31. Allocation

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