1. Total Maximum Daily Loads Development for Holdens Creek and Tributaries, and Pettit Branch
Public Meeting
March 26, 2008

2. Why Are We Here Learn about water quality of these streams
Discuss the Total Maximum Daily Load (TMDL) development
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
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
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. Pettit Branch Watershed
Fecal Bacteria TMDLs for Holdens Creek and Tributaries, and Pettit Branch
Holdens Creek Watershed
Virginia
Eastern Shore
7-PET000.80
Pettit Branch Watershed

6. What Are Fecal Coliform, E. coli, and Enterococci?
Coliform Bacteria: Common in soil, decaying vegetation, animal feces, and raw surface water
Fecal Coliform: Found in the digestive tract of humans and warm blooded animals; Indicator of the potential presence of pathogens in water bodies
Enterococci: a type of fecal streptococci; provide a higher correlation than fecal coliform with human pathogens
E. coli: Subset of fecal coliform; Correlate better with swimming associated illness

7. Water Quality Criteria
Name
Water Type
Designated
Use
Criteria (per 100 ml)
Listing
Year
Holdens Creek
(Upper)
Class II
Transition
Recreation
Enterococci maximum<104
2006
(Upper+Lower)
+Tidal
Shellfishing
Fecal Coliform 30-month
geo. mean<14;
90th percentile<49
1998
Sandy Bottom Br.
Class III
Nontidal
E. Coli maximum<235
Un. Trib. to Sandy Bottom Br.
2004
Pettit Br.

8. Fecal Coliform Exceedances in Holdens Creek
Last 30 Months
Criteria
Observed
Geo. Mean 14
193
90th Percentile 49
435
Station 7-HLD002.67
49/100ml
14/100ml

9. Enterococci Exceedances in Holdens Creek
Criterion
Exceedance
Maximum<104
76%
Station 7-HLD002.67
104/100ml

10. E. Coli Exceedances in Sandy Bottom Branch
Criterion
Exceedance
Maximum < 235
43%
Station 7-SBB000.17
235/100ml

11. E. Coli Exceedances in Unnamed Tributary to Sandy Bottom Branch
Criterion
Exceedance
Maximum < 235
27%
Station 7-XAZ000.30
235/100ml

12. E. Coli Exceedances in Pettit Branch
Criterion
Exceedance
Maximum < 235
59%
Station 7-PET000.80
235 / 100ml

13. Creek Watershed Land Use
Holdens
Creek Watershed Land Use

14. Pettit Branch Watershed Land Use

15. Potential Bacteria Sources
Humans
Pets
Livestock
Wildlife

16. Potential Source: Human Contribution

17. Failing Septic Tanks Permitted Source Watershed City Name
# of
Tanks
Person
/Tank FC
Producing Rate
(cfu/d/person)
Tank
Failing
Rate
Loads
(cfu/d)
Holdens Creek
626
2.7
1.95×109
12%
3.96×1011
Pettit Branch
126
7.96×1010
Permitted Source
Watershed
City
Name
Permitted Type
Holdens Creek
Temperanceville
Tyson Farms, Inc
VPDES

18. Potential Sources: Wildlife, Livestock, and Pet
Pettit Branch
Holdens Creek
Dogs 29
287
Livestock
Cattle 3 17
Swine 6 44
Chickens
24,926
176,680
Horses 1 4
Sheep
Wildlife
Ducks 39
340
Geese
253
Deer 32
309
Raccoons 37
385

22. Bacteria Source Tracking (BST) Data Will Be Available by the End of March
Uses Antibiotic Resistance Analysis for source load allocation into 4 categories
Human
Pets
Livestock
Wildlife

23. Un. Trib. to Sandy Bottom Br.
TMDL End Point
Name
Water Type
Designated
Use
Criteria (per 100 ml)
Holdens Creek
(Upper)
Class II
Transition
Recreation
Enterococci maximum<104
(Upper+Lower)
+Tidal
Shellfishing
Fecal Coliform 30-month
geo. mean<14;
90th percentile<49
Sandy Bottom Br.
Class III
Nontidal
E. Coli maximum<235
Un. Trib. to Sandy Bottom Br.
Pettit Br.

24. Holdens Creek Enterococci TMDL: Recreational Use
DEQ translator: convert the enterococci criterion of
104 counts/100 ml to fecal coliform equivalent criterion
Fecal coliform = 551 counts/100 ml
One order of magnitude higher than the shellfish criterion
The former will be met simultaneously as the latter is attained

25. Modeling Approach Reduction (%) Flow Observations (concentration)
Temperature
(decay)
Model prediction
Model
Compare to observations
(calibration)
Adjust Loading
Results are good
(statistics)
Loading
Existing Loads
Reduction (%)
TMDL
Compare to Criteria
Results are good
Adjust Loading
Loading
Water Quality Criteria
Model prediction
Model
Temperature
(decay)
Flow

26. Modeling Approach: Linking Sources to Water Quality
Sandy Bottom Branch, Unnamed Tributary to Sandy Bottom Branch, and Pettit Branch
Input
Observed bacteria concentration or water quality criterion
Bacteria decay rate
Simulated flow information
Stream cross-sectional area
Distributed-Source Model
No tidal influence
The watershed associated with the head water is small
Assume the bacteria are discharged laterally into the stream and fully mixed laterally and vertically
Using Bayesian method to handle uncertainties
Output
Existing bacteria load and loading capacity (TMDL) under different flow regimes

27. Tidally Averaged Transport Model
Holdens Creek
Input
Observed bacteria concentration or water quality criterion
Bacteria decay rate
Simulated flow information
Stream cross-sectional area
Tidally Averaged Transport Model
Tidal influence
Applies to long and narrow estuaries
Assume the bacteria are discharged laterally into the stream and fully mixed laterally and vertically
Using Bayesian method to handle uncertainties
Output
Existing bacteria load and loading capacity (TMDL)

28. Model results of Holdens Creek

29. Reduction Simulation (Sandy Bottom Branch and Unnamed Tributary)

30. Loading Allocations Non-point Source: To be determined using BST data
Point Source (if present in watershed):
Based on permit limits and discharge monitoring reports
Use existing maximum loading discharged to the stream

31. Summary of the TMDLs
Sandy Bottom Branch and Unnamed Tributary to Sandy Bottom Branch E. Coli TMDL Recreational Use
Flow Interval I
Flow >70% II
70% <Flow <30%
III
Flow<30%
Flow (cfs)
0.46
1.77
5.62
TMDL (Count/Day)
3.46E+09
1.23E+10
3.84E+10
WLA (Count/Day)
1.65E+09
LA (Count/Day)
1.81E+09
1.06E+10
3.67E+10
MOS
Implicit

32. Holdens Creek Fecal Coliform TMDL: Shellfish Growing Water Use
Category
Criterion
(MPN/100ml)
Existing Load
(Counts/day)
Allowable Load
Required
Reduction
Geometric Mean 14
1.58E+12
3.34E+12
78.85%
90th Percentile 49
7.59E+13
7.09E+12
90.66%
Category
TMDL
(Counts/day)
WLA LA
MOS
Geometric
Mean
3.34E+12 na
Implicit
90th
Percentile
7.09E+12

33. Pettit Branch

34. Pettit Branch TMDL

35. Continue Work Conduct load allocations using BST data
Respond to comments
Finalize TMDL reports

36. Questions?