Public Meeting February 3, 2010 Total Maximum Daily Loads Development for Sandy Bottom Branch and Unnamed Tributary to Sandy Bottom Branch Public Meeting February 3, 2010

Why We Are Here To learn about the water quality of Sandy Bottom Branch (SBB) and Unnamed Tributary to Sandy Bottom Branch (UTSBB) To discuss the Total Maximum Daily Load (TMDL) development To gather comments and encourage public participation

The TMDL Process DEQ routinely monitors the quality of waters across the state and publishes a list of impaired waters every 2 years (303(d) list) Virginia is required by 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 (WQS) Recreation Aquatic life Fishing Shellfishing Drinking water Wildlife 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

SBB and UTSBB were first listed on 303(d) Water Quality Integrated Report in 2004 and 1998 due to WQS violations for aquatic life use. Landuse: Dominated by forest (50.9%) & agriculture (39.4%)

Stressor Identification To identify what pollutant(s) is(are) causing the benthic community impairment Common stressors: Dissolved Oxygen Nutrients pH Temperature Sediment Toxics

Stressor Identification Data used in Stressor Identification process: Biological monitoring data Habitat assessment data In-stream water quality data Each candidate stressor was evaluated based on available data and consideration of potential sources in the watershed Potential stressors were further classified as non-stressors, possible stressors, or most probable stressors

VADEQ Biological Monitoring Data (1994-2007) Coastal Plain Macroinvertebrate Index (CPMI): collecting, aggregating, and interpreting benthic macroinvertebrate data At 7-XAZ000.30, from 1994 to 2004, 4 out of 22 assessments indicated “severe impairment”. From 2005 on, all the assessments indicated “slight” or “moderate impairment” No severe impairments at 7-SBB000.17

Habitat Assessment Scores 0-very poor; 20-optimal. The scores were compared with a reference site. Total score of the impacted site > reference site, indicating the habitat quality does not play a significant role in the benthic impairment. Definition Impacted Reference Channel Modification Channelization or dredging conditions 10 15 In-stream Habitat Scored based on the value of in-stream habitat to the fish community 14 16 Pools Variety and complexity of slow or still Water habitat present at a site Bank Stability Scored based on the stability of the bank 12 Bank Vegetative Type Types of vegetations on banks 13 Shading Ratio of stream that is shaded Riparian Zone Width Minimum width of vegetated riparian Buffer 18 5 Total 100 90

Ambient Water Quality Monitoring Data

Organic Contaminants No data collected in the water column. Sediment organics data were available at Station 7-SBB000.17: aldrin, chlordane, DDT, DDD, DDE, dicofol, dieldrin, endrin, heptachlor epoxide, heptachlor, PCBs, and toxaphene. All of them were below the detection limits or the standards.

Heavy Metals Measured heavy metals: arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), thallium (Ti), and zinc (Zn) In the sediment, heavy metals were below the standards or the detection limits, or did not have standards, except that one measurement at Station 7-XAZ000.30 in 1990 had spiked Cr concentration. In the water column, all heavy metals complied with WQC or did not have an established WQC, except Cu.

Point Source Data: Tyson Farms Inc. In February 2005, when Tyson Farms adopted a new Cu permit, the water column Cu has been decreasing. The benthic macroinvertebrate conditions have improved and expecting a full recovery in the future. At the time Tyson Farms also adopted a new TP permit, the water column TP concentration was greatly decreased but still higher than the VA screening level for eutrophication. There is no criterion for direct TP toxicity.

Stressor Identification Summary Category Candidate Non-Stressors Low DO, pH, Temperature, Dissolved Heavy Metals in Water Column except Cu, Heavy Metals in Sediment, Organic Contaminants in Sediment Possible Stressors Nutrients, Chloride Dissolved Cu in Water Column More data are needed to confirm the stressors

DEQ Random Water Quality Data (June 2009) Parameters of Concern SBB UTSBB Copper (Dissolved, ug/L) 4.44 4.47 TP (mg/L as P) 1 Hardness (mg/L) 107 106 Water column hardness-adjusted copper criteria : Chronic 9.5, Acute 14.3 ug/L TP screening level for eutrophication: 0.2 mg/L

VIMS Random Copper Data in the Sediment (July 2009) Location Average (mg/kg) SBB (Sample 1) 3.93 SBB (Sample 2) 11.90 UTSBB (Sample 1) 6.38 UTSBB (Sample 2) 15.44 Sediment copper criterion : 149 mg/kg

Stressor Identification Summary Category Candidate Non-Stressors Low DO, pH, Temperature, Dissolved Heavy Metals in Water Column except Cu, Heavy Metals in Sediment, Organic Contaminants in Sediment Possible Stressors Nutrients, Chloride Most Probable Stressors Dissolved Cu in Water Column There is no identifiable stressor after 2005

TMDL Develop conventional TMDLs for Cu and total phosphorus based on Tyson permit limits

Conventional Cu TMDL Development Source Assessment Point Source -- Tyson Farms Monthly average 16 ug/L, and maximum 22 ug/L Nonpoint Source -- Background Cu washed off from soils in the watershed

Verification of Complance TMDL Endpoint: Hardness-Dependent Freshwater acute criterion (mg/l) WER [e{0.9422[ln(hardness)]-1.700}] (CFa) Freshwater chronic criterion (mg/l) WER [e{0.8545[ln(hardness)]-1.702}] (CFc) WER = Water Effect Ratio =1 unless shown otherwise under 9 VAC 25-260-140.F and listed in 9 VAC 25-260-310. CFa = 0.960; CFc = 0.960

Distributed-Source Model (2) Modeling Approach: Linking Sources to Water Quality Observed Cu Concentration at Monitoring Station Simulated flow information Stream width, depth, and length Background Cu concentration Point source observations The permitted dissolved Cu concentration of the point source (1) Distributed-Source Model (2) Predict whether Cu concentration at DEQ station meets the WQC Water Column Cu Loss Rate Step (1): Calculate the water column Cu loss rate Step (2): Using the point source permitted Cu, predict whether Cu concentration at DEQ station meets the WQC

Distributed-Source Model: Assumptions: Non-point source loads are discharged laterally into the system Cu is fully mixed laterally and vertically Non-Point Source Point Source S0: nonpoint source load k: Cu first-order loss rate u: water velocity, u =Q/A (in-stream flow/cross-sectional area) x: distance measured from headwater C0: Cu concentration of the point source discharge

Flow Estimation: To estimate the velocity, u, an in-stream flow Q is required. The LSPC model was calibrated against USGS Gage 01484800 in Guy Creek near Nassawadox and used to simulate the daily flow.

The average in-stream dissolved Cu concentration in Eastern Shore was used as the background concentration (0.682±0.295 ug/L) for SBB. The measured Cu at Station 7-SBB000.17 was subtracted by it, thus S0 becomes 0. k=0.18/day q1, q2, and qTyson are the background flows from sub-watersheds 1 and 2, and Tyson Farms Station 7-XAZ000.30 does not have enough data. Therefore it was not included in the calculation

Comparison of C3 and the Criteria Consequently, the permit level of Tyson Farms 16 ug/L total Cu (12.2 ug/L dissolved Cu) is substituted into the equation (as C02). Then C3, the Cu concentration at DEQ station 7-SBB000.17 was calculated for low, median, and high flows, under the average hardness condition of 97 mg/L. Comparison of C3 and the Criteria Average Hardness (mg/L CaCO3) Criteria (ug/L) C3 (ug/L) Chronic Acute High Flow Median Low 97 8.73 13.06 6.76 7.62 8.56

TMDL Summary (g/day) for SBB and UTSBB Flow Region High Median Low WLA 40.51 LA 11.98 5.10 1.82 MOS 5.83 5.07 4.70 TMDL 58.32 50.68 47.03

Phosphorus TMDL Monthly mean 2 mg/L Maximum NA No in-stream water quality criteria for benthic community for total phosphorus WLA = current loading

Recommendations for TMDL Implementation No reduction from either point source or nonpoint source is needed as the WQC are met at the DEQ station and the benthic macroinvertebrates are recovering. Monitoring will continue to assess implementation measures. The TMDL will be re-examined at the conclusion of the 2012 assessment cycle if attainment has not been met.

Continued Work Collect comments and suggestions Finalize TMDL report

Questions?