Chowan River TMDL Development Blackwater Area 09/07/04

Impaired Waters in the Blackwater River Drainage Rattlesnake Creek Swamp – Fecal Coliform Mill Swamp – Fecal Coliform Cypress Swamp – Fecal Coliform Spring Branch – General Standard (Benthic)

TMDL Development Historical data analysis Source assessment Physical Source Identification Bacterial source tracking Modeling Allocation

Fecal Coliform Impairments Impaired Stream Segments in the Blackwater River watershed

Water Quality Data Analysis Location of VADEQ water quality monitoring stations used for TMDL assessment in the Blackwater River watershed

Water Quality Data Analysis Fecal Coliform Concentrations

Water Quality Data Analysis Location of BST water quality monitoring stations in the Blackwater River watershed

Water Quality Data Analysis E. coli concentrations

Water Quality Data Analysis Statistical Analysis of Water Quality Measurements versus Precipitation to determine the relationship between rainfall and water quality Analyzed relationships for seasonal trends No seasonal trends found

Source Assessment Identification of Sources DEQ/DCR/Locality records VPDES U.S. Census Ag Census Habitat Analysis Stakeholders, local knowledge – improve estimates BST Delivery Mechanisms Direct Land-applied Exported Out of Watershed Temporal Variation Migration Patterns/Resident Populations Import/Export of agricultural/STP waste?

Permitted Discharges

Human (2004) ImpairmentPopulation Housing Units (HU) HU with Sewer HU with Septic HU with Other Cypress Swamp 1, Mill Swamp Rattlesnake Swamp 843 1,

Human 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

Pets (2004) ImpairmentDogsCats Cypress Swamp Mill Swamp Rattlesnake Swamp

Livestock ImpairmentBeefDairyHorseSheepPoultrySwine Cypress Swamp Mill Swamp Rattlesnake Swamp ,335 4,759 6,908

Wildlife Population ImpairmentDeerTurkeyGooseDuckMuskratRaccoonBeaver Cypress Swamp Mill Swamp Rattlesnake Swamp ,968 9,432 12,007

Bacterial Source Tracking Location of BST stations in the Blackwater River watershed

Modeling Hydrologic model Runoff model HSPF Water Quality model HSPF Model Calibration and Validation Based on data availability, period of interest

Modeling

Determination of Critical Conditions: Observed Fecal Coliform Versus Stream Flow Cypress Swamp: VADEQ Station 5ACPP and USGS Station #

Determination of Critical Conditions: Observed Fecal Coliform Versus Stream Flow, cont. Cypress Swamp: VADEQ Station 5ACPP and USGS Station #

Determination of Critical Conditions: Observed Fecal Coliform Versus Stream Flow, cont. Rattlesnake Creek Swamp: VADEQ Station 5ARKN and USGS Station #

Determination of Critical Conditions: Observed Fecal Coliform Versus Stream Flow, cont. Mill Swamp: VADEQ Station 5AMSW and USGS Station #

Hydrologic Calibration

Modeling Source Loads Source Characterization Fecal production / densities / distribution Delivery Mechanisms Direct Land-applied Exported Out of Watershed Temporal Variation

Load Characteristics

Model Load Characterization “Direct to Stream” Loads Point Sources: Design Flow/Fecal Discharge Overflows: Reported overflow volume Characterize Volume and Duration Animal/Human: direct deposition, straight pipes “Land Applied” Loads Wildlife, Livestock, Pets Transported to stream during runoff producing event Use measured waste characteristics Compute die-off in between events Application timing

Wildlife

Livestock Average percentage of collected livestock waste applied throughout year

Livestock Average time dairy milking cows spend in different areas per day

Livestock Average time dry cows and replacement heifers spend in different areas per day

Livestock Average time beef cows not confined in feedlots spend in areas per day

Allocation Quantify Current Source Conditions Run model with present-day sources 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

Livestock ImpairmentBeefDairyHorseSheepSwine Cypress Swamp ,117 Mill Swamp ,957 Rattlesnake Swamp ,236 * Must get information regarding import/export of poultry litter in watershed.

Allocation