1. 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

2. 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

3. 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

4. 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

5. 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%)

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

7. 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

8. 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

9. 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

10. Ambient Water Quality Monitoring Data

12. 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.

13. 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-XAZ 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.

14. 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.

15. 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

16. 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

17. 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

18. 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

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

20. 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

21. 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 F and listed in 9 VAC
CFa = 0.960; CFc = 0.960

22. 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

23. 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

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

25. 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-SBB 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-XAZ does not have enough data. Therefore it was not included in the calculation

26. 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-SBB 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

27. 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

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

29. 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.

30. Continued Work
Collect comments and suggestions
Finalize TMDL report

31. Questions?