Haw,Deep,etc.TurbidityFecalTMDL

Total Maximum Daily Load for Turbidity and Fecal Coliform for
Haw River, Deep River, Third Fork Creek, and Dan River in North
Carolina

Final Report
















 

 
 

 



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Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
i
SUMMARY SHEET
Total Maximum Daily Load (TMDL)

1. 303(d) Listed Water Body Information
State: North Carolina
Counties: Alamance, Caswell, Durham, Forsyth, Guilford, Randolph, Rockingham,
Stokes, and Surry
Major River Basins: Cape Fear River Basin (03030002 & 03030003) and Roanoke
River Basin (03010103)
Watersheds: Haw River, Deep River, Third Fork Creek, and Dan River

Impaired Water Body (2002 303(d) List):
Water Body Name -
(AU)
Water Quality
Classification
Subbasin
6-digit Code Impairment Length
(mi)
Haw River – 16-(1)d C - Aquatic life and
secondary contact recreation
03-06-02 Turbidity 13
Haw River – 16-(1)d C - Aquatic life and
secondary contact recreation
03-06-02 Fecal Coliform 13
Deep River - 17-(4)b WS-IV – Potable water
supply
03-06-08 Fecal Coliform 6.8
Third Fork Creek
16-41-1-12-(2)
WS-IV - Potable water
supply
03-06-05
Turbidity 3.6
Dan River – 22-(31.5)WS-IV - Potable water
supply
03-02-03 Turbidity 14.2

Constituent(s) of Concern: Fecal Coliform Bacteria and Turbidity
Designated Uses: Biological integrity, water supply, propagation of aquatic life, and recreation.

Applicable Water Quality Standards for Class C and Class WS IV Waters:
• Turbidity: not to exceed 50 NTU
• Fecal coliform shall not exceed a geometric mean of 200/100 mL (membrane filter count)
based upon at least five consecutive samples examined during any 30 day period, nor
exceed 400/100 mL in more than 20 percent of the samples examined during such period.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
ii
2. TMDL Development
Analysis/Modeling:
Load duration curves based on cumulative frequency distribution of flow conditions in the
watershed. Allowable loads are average loads over the recurrence interval between the 95th and
10th
percent flow exceeded (excludes extreme drought (>95th
percentile) and floods (<10th
percentile). Percent reductions expressed as the average value between existing loads (typically
calculated using an equation to fit a curve through actual water quality violations) and the
allowable load at each percent flow exceeded.

Critical Conditions:
Critical conditions are accounted in the load curve analysis by using an extended period of
stream flow and water quality data, and by examining at what flow (percent flow exceeded) the
existing load violations occur.

Seasonal Variation:
Seasonal variation in hydrology, climatic conditions, and watershed activities are represented
through the use of a continuous flow gage and the use of all readily available water quality data
collected in the watershed.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
iii
3. Allocation Watershed/Stream Reach
Pollutants /
Watersheds
Existing
Load
WLA1 LA MOS TMDL Percent
Reduction
I. TSS
(tons/day)
Haw River
Third Fork
Dan River

II. Fecal
Coliform
(#/day)
Haw River
Deep River

183.16
1.58
248.20

1.44E+13
2.47E+12

22.31
0.36
1.21

1.79E+12
5.87E+11

48.95
0.39
100.53

1.56E+12
3.42E+10

Explicit 10 %
Explicit 10 %
Explicit 10 %

Explicit 10 %
Explicit 10 %

71.26
0.75
101.74

3.35E+12
6.22E+11

61
53
59

77
75

Notes:
WLA = wasteload allocation, LA = load allocation, MOS = margin of safety.
1. WLA = TMDL – LA - MOS; where TMDL is the average allowable load between the 95th
and 10th percent flow exceeded.
2. Margin of safety (MOS) equivalent to 10 percent of the target concentration for fecal coliform and turbidity.
3. Turbidity is not a concentration and, as a measure, cannot be directly converted into loadings required for the TMDL. Total
suspended solids (TSS) was therefore selected as the surrogate measure for turbidity and used to develop the TMDL target and
limits (USEPA 1999).

4. Public Notice Date: September 16, 2004
5. Submittal Date: November 3, 2004
6. Establishment Date:
7. EPA Lead on TMDL (EPA or blank): No
8. TMDL Considers Point Source, Nonpoint Source, or both: Both

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
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Table of Contents
1. Introduction...............................................................................................................................................3
1.1. Watershed Description......................................................................................................................6
1.2. Water Quality Target: North Carolina Water Quality Standard.....................................................14
1.2.1. Water Quality Standard for Turbidity ......................................................................................14
1.2.2. Water Quality Standard for Fecal Coliform.............................................................................14
1.3. Water Quality Monitoring...............................................................................................................14
1.3.1. Turbidity...................................................................................................................................15
1.3.2. Fecal Coliform..........................................................................................................................16
2. General Source Assessment ....................................................................................................................18
2.1. General Sources of Turbidity..........................................................................................................18
2.1.1. Non-point Sources of Turbidity ...............................................................................................18
2.1.2. Point Sources of Turbidity .......................................................................................................19
2.2. General Sources of Fecal Coliform.................................................................................................20
2.2.1. Non-point Sources of Fecal Coliform......................................................................................20
2.2.2. Point Sources of Fecal Coliform..............................................................................................22
3. Haw River Impairment............................................................................................................................24
3.1. Source Assessment......................................................................................................................24
3.1.1. NPDES Wastewater Permits....................................................................................................24
3.1.2. NPDES General Permits ..........................................................................................................25
3.1.3. NPDES Stormwater MS4s .......................................................................................................26
3.1.4. Livestock Populations ..............................................................................................................26
3.1.5. Septic Tanks.............................................................................................................................27
3.2. Technical Approach ........................................................................................................................28
3.2.1. Endpoint for Turbidity..............................................................................................................28
3.2.2. Endpoint for Fecal Coliform ....................................................................................................29
3.2.3. Flow Duration Curve................................................................................................................29
3.2.4. Load Duration Curve................................................................................................................30
3.3. Total Maximum Daily Loads (TMDL)...........................................................................................33
3.3.1. Margin of Safety (MOS) ...........................................................................................................34
3.3.2. Target Reduction.......................................................................................................................34
3.3.3. TMDL Allocation.....................................................................................................................37
3.3.4. Critical Condition and Seasonal Variation...............................................................................39
4. Deep River Impairment...........................................................................................................................40
4.1. Source Assessment......................................................................................................................40
4.1.1. NPDES Wastewater Permits....................................................................................................40
4.1.2. NPDES General Permits ..........................................................................................................40
4.1.3. NPDES Stormwater MS4s .......................................................................................................40
4.1.4. Livestock Populations ..............................................................................................................41
4.1.5. Septic Tanks.............................................................................................................................41
4.2. Technical Approach ........................................................................................................................42
4.2.1. Endpoint for Fecal Coliform ....................................................................................................42
4.2.2. Flow Duration Curve................................................................................................................43
4.2.3. Load Duration Curve................................................................................................................44
4.3. Total Maximum Daily Loads (TMDL)...........................................................................................45
4.3.1. Margin of Safety (MOS) ...........................................................................................................45
4.3.2. Target Reduction.......................................................................................................................45
4.3.3. TMDL Allocation.....................................................................................................................47
4.3.4. Critical Condition and Seasonal Variation...............................................................................48
5. Third Fork Creek Impairment .................................................................................................................49
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
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5.1. Source Assessment..........................................................................................................................49
5.1.1. NPDES Wastewater Permits....................................................................................................49
5.1.2. NPDES General Permits ..........................................................................................................49
5.1.3. NPDES Stormwater MS4s .......................................................................................................49
5.2. Technical Approach ........................................................................................................................50
5.2.1. Endpoint for Turbidity..............................................................................................................50
5.2.2. Flow Duration Curve................................................................................................................50
5.2.3. Load Duration Curve................................................................................................................51
5.3. Total Maximum Daily Loads (TMDL)...........................................................................................53
5.3.1. Margin of Safety (MOS) ...........................................................................................................53
5.3.2. Target Reduction.......................................................................................................................53
5.3.3. TMDL Allocation.....................................................................................................................55
5.3.4. Critical Condition and Seasonal Variation...............................................................................56
6. Dan River Impairment.............................................................................................................................57
6.1. Source Assessment..........................................................................................................................57
6.1.1. NPDES Wastewater Permits....................................................................................................57
6.1.2. NPDES General Permits ..........................................................................................................58
6.1.3. NPDES Stormwater MS4s .......................................................................................................59
6.2. Technical Approach ........................................................................................................................59
6.2.1. Endpoint for Turbidity..............................................................................................................59
6.2.2. Flow Duration Curve................................................................................................................59
6.2.3. Load Duration Curve................................................................................................................60
6.3. Total Maximum Daily Loads (TMDL)...........................................................................................62
6.3.1. Margin of Safety (MOS) ...........................................................................................................62
6.3.2. Target Reduction.......................................................................................................................62
6.3.3. TMDL Allocation.....................................................................................................................64
7. Summary and Future Consideration........................................................................................................65
7.1 Stream Monitoring ............................................................................................................................66
7.2 Implementation Plan .........................................................................................................................66
8. Public Participation.................................................................................................................................67
9. Further Information.................................................................................................................................67
10. References............................................................................................................................................68
11. APPENDICES.......................................................................................................................................70
Appendix 11.1. Water Quality Parameters Used for TMDL Development..........................................70
Appendix 11.2. NPDES Permits ............................................................................................................76
Appendix 11.3. Load Reduction Estimations.........................................................................................78
Appendix 11.4. Estimates of Relative Loadings for Point and Non-point Sources ...............................82
Appendix 11.5. Public Notice ................................................................................................................84
Appendix 11.6. Public Comments and DWQ Response........................................................................89

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
3

1. Introduction
This report presents the development of Total Maximum Daily Loads (TMDLs) for four water
bodies in North Carolina: Haw River, Deep River, Third Fork Creek, and Dan River. The first
three water-bodies are located in the Cape Fear River Basin (CFRB) (Figure 1.1) while the Dan
River is located in the Roanoke River Basin (RRB) (Figure 1.2). As identified by the North
Carolina Division of Water Quality (DWQ), the impaired segments of the four water bodies are
as follows (NCDENR 2003):

• The Haw River in the CFRB is impaired due to fecal coliform and turbidity. The
impaired segment is located in sub-basin 30602 from NC 87 to NC 49. This section of
the river runs approximately 13 miles and is designated as a class C water1.

• The Deep River in the CFRB is impaired due to fecal coliform. The impaired segment is
located in sub-basin 30608 from SR 1113 to SR 1921. This section of the stream runs
approximately 7 miles and is designated as a class WS-IV water2.

• The Third Fork Creek in the CFRB is impaired due to turbidity. The impaired segment is
located in sub-basin 30605 from 2.0 miles upstream of NC Hwy 54 to New Hope Creek.
This section of the stream runs approximately 4 miles and is designated as a class WS-IV
water2.

• The Dan River in the RRB is impaired due to turbidity. The impaired segment is located
in sub-basin 30203 from a point 0.7 mile upstream of Jacobs Creek to a point of 0.8 mile
down stream of Matrimony Creek. This section of the stream runs approximately 14
miles and is designated as a class WS-IV water2.

Section 303(d) of the Clean Water Act (CWA) requires States to develop a list of water bodies
that do not meet water quality standards or have impaired uses. The list, referred to as the 303(d)
list, is submitted biennially to the U.S. Environment Protection Agency (USEPA) for review.
The 303(d) process requires that a Total Maximum Daily Load (TMDL) be developed for each
of the waters appearing on Category 5 of the 303(d) list.

1 Class C waters are protected for secondary recreation, fishing, wildlife, fish and aquatic life propagation
and survival, agriculture and other uses suitable for class C. There are no restrictions on watershed
development or types of discharges.

2 Class WS-IV waters are used as sources of potable water supply where WS-1, WS-II or WS-III
classification is not feasible. WS-IV waters are generally in moderately to highly developed watersheds or
Protected Areas, and involve no categorical restrictions on discharges.
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
4

Figure 1.1. Upper Cape Fear River Basin showing Haw River, Deep River, and Third Fork
Creek and water quality stations along the main water bodies.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
5

Figure 1.2. Roanoke River Basin showing the Dan River and water quality stations along the
main water body.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
6

The objective of a TMDL is to allocate allowable pollutant loads to known sources so that
actions may be taken to restore the water to its intended uses (USEPA, 1991). Generally, the
primary components of a TMDL, as identified by USEPA (1991, 2000a) and the Federal
Advisory Committee (FACA) (USEPA, 1998) are as follows:

Target identification or selection of pollutant(s) and end-point(s) for consideration. The
pollutant and end-point are generally associated with measurable water quality related
characteristics that indicate compliance with water quality standards. North Carolina
indicates known pollutants on the 303(d) list.
Source assessment. All sources that contribute to the impairment should be identified and loads
quantified, where sufficient data exist.
Assimilative capacity estimation or level of pollutant reduction needed to achieve water quality
goal. The level of pollution should be characterized for the water body, highlighting how
current conditions deviate from the target end-point. Generally, this component is
identified through water quality modeling.
Allocation of pollutant loads. Allocating pollutant control responsibility to the sources of
impairment. The waste load allocation portion of the TMDL accounts for the loads
associated with existing and future point sources. Similarly, the load allocation portion
of the TMDL accounts for the loads associated with existing and future non-point
sources, storm water, and natural background.
Margin of Safety. The margin of safety addresses uncertainties associated with pollutant loads,
modeling techniques, and data collection. Per EPA (2000a), the margin of safety may be
expressed explicitly as unallocated assimilative capacity or implicitly due to conservative
assumptions.
Seasonal variation. The TMDL should consider seasonal variation in the pollutant loads and
end-point. Variability can arise due to stream flows, temperatures, and exceptional
events (e.g., droughts, hurricanes).

Section 303(d) of the CWA and the Water Quality Planning and Management regulation
(USEPA, 2000a) requires EPA to review all TMDLs for approval. Once EPA approves a
TMDL, then the water body may be moved to Category 4a of the 303(d) list. Water bodies
remain on Category 4a of the list until compliance with water quality standards is achieved.
Where conditions are not appropriate for the development of a TMDL, management strategies
may be implemented in an effort to restore water quality.

1.1. Watershed Description
Watershed areas that contributed turbidity and fecal coliform in the polluted section of the water
bodies are manually delineated using the delineation tools provided in version 3.0 of the Better
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
7
Assessment Science Integrating Point and Non-point Sources (BASINS) system. The
delineation of the watersheds was done to understand land use compositions in each watershed.
The land use compositions were estimated using the BASINS default land use data, which was
based on the USGS Geographic Information Retrieval and Analysis System (GIRAS). The
GIRAS was developed on mid 70s; therefore, the land use compositions do not reveal the current
land use status. However, it provides a comprehensible understanding of the distribution pattern
of the land uses in the watersheds. The delineated watersheds and their land use distributions are
shown in Figures 1.3 through 1.6. Statistics of the land use coverage are presented in Table 1.1.

Table 1.1. Land use acreages and their percent compositions in the four watersheds.
Haw River Deep River Third Fork
Creek
Dan River Land Use
Area
(sq.mi)
Area
(%)
Area
(sq.mi)
Area
(%)
Area
(sq.mi)
Area
(%)
Area
(sq.mi)
Area
(%)
Urban 112.00 18.49 36.93 29.54 9.75 59.16 33.97 2.98
Agriculture 280.40 46.27 33.68 26.94 X X 327.64 28.74
Forest 200.10 33.02 51.31 41.05 6.25 37.93 769.39 67.49
Water/Wetland 12.18 2.01 1.93 1.54 0.03 0.21 7.30 0.64
Barren 1.15 0.19 1.18 0.94 0.44 2.69 1.60 0.14
Total 606.00 100 125.01 100 16.48 100 1,139.89 100

The Haw River, Deep River, and Third Fork Creek watersheds are spread the upper piedmont of
North Carolina. The Dan River watershed is alternately flows between Virginia and North
Carolina. The impaired segment of the river is located in North Carolina (Figure 1.6).

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
8

Figure 1.3. Mid 70’s land use distribution in the Haw River watershed

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
9

Figure 1.4. Mid 70’s land use distribution in the Deep River watershed.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
10

Figure 1.5. Mid 70’s land use distribution in the Third Fork Creek watershed.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
11

Figure 1.6. Mid 70’s land use distribution in the Dan River watershed.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
12
Dominating characteristics of land uses in the four watersheds vary. Agricultural and forested
lands dominated the land uses in the Haw River watershed. Forested lands dominated the land
uses in the Deep River and Dan River watersheds, whereas urban land dominated the land uses
in Third Fork Creek watershed.

In recent years, significant developments have occurred and resulted in conversion of large rural
parcels into residential and commercial areas in the watersheds. According to the U.S. Census,
1990 and 2000, population increased by 21 percent in Guildford and Alamance Counties.
Likewise seven percent was encountered in Rockingham County. These three counties
encompass the Haw River, Deep River, and Dan River watersheds. Similarly, population in
Durham and Stokes Counties increased by 23 percent and 20 percent respectively. These two
counties encompass the polluted section of the Third Fork Creek and Dan River watersheds
respectively. The Dan River watershed also spreads through Patrick County and Henry County
in Virginia. Population increments in the two counties were only 11 percent and 1 percent
respectively, which is indeed comparatively insignificant.

Conversion of rural areas to urban land uses can significantly enhance soil erosion. Higher
imperviousness of the new land use increases urban runoff volume and therefore, results in
erosion of surface soils and stream channels. The DWQ conducted a special study in the Haw
River watershed to understand the magnitude of sediment loading due to urbanization. The
DWQ collected water samples at the ambient station, B1140000, in the watershed for a six-week
period from 01/06/04 through 02/16/04. The station is located approximately 0.15 miles
downstream from Hwy 49, at USGS station # 02096500, and receives runoff from both
agricultural and urban lands. The major urban areas are Greensboro and Burlington.

Two major storm events occurred during the special study period (Figure 1.7). The first storm
event occurred during the early morning of 2/3/04. The storm increased the flow from 381 cfs to
3170 cfs in the Haw River at B1140000. The storm event occurred very rapidly over a period of
approximately six hours with a precipitation total of 0.61 inches. In addition, runoff in the
drainage area was enhanced due to ground saturation from the previous week ice storm. The
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
13
storm event carried substantial amount of sediment and solid materials from urban as well as
agricultural lands, and the turbidity level increased from 7.6 NTU to 102 NTU (Figure 1.7).

Figure 1.7. Association between turbidity and flow in the Haw River at ambient station
B1140000.

The second storm event occurred on 02/06/04 and continued to 02/07/04 with 0.52 inches of
precipitation. The saturated ground conditions from the previous storm events further enhanced
the runoff throughout the watershed. Flow at the ambient station, B1140000, increased from 748
cfs to 4,390 cfs, and turbidity levels increased from 24 NTU to 175 NTU.

During the six weeks period, a significant relationship between turbidity and flow was observed
in the Haw River, where urban lands are rapidly expanding. The relationship is given in
Equation 1.1 below. In the Haw River, turbidity increased by 0.03 NTU for every flow increase
and remained constant at 5.67 NTU on an average during no flow period.

Turbidity = 5.67 + 0.03 * Flow R-Square = 0.66 ----------------------------(1.1)

The conversion of rural land uses will shift the non-point source contribution of fecal coliform
from agriculture activities such as cattle grazing and manure application to urban sources such as
fecal waste from waste household pets, sanitary sewer overflows (SSOs) and leaking sewer lines.
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
02
0
0
10
0
0
18
0
0
24
0
0
08
0
0
16
0
0
24
0
0
08
0
0
16
0
0
24
0
0
08
0
0
16
0
0
24
0
0
08
0
0
14
0
0
22
0
0
06
0
0
14
0
0
22
0
0
Sampling Time (hrs) and Date
Fl
o
w

(
c
f
s
)
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
180.0
200.0
Tu
r
b
i
d
i
t
y

(
N
T
U
)
Flow Turbidity
2/3/04 2/6/042/5/042/4/04 2/8/042/7/04
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
14
Generally, fecal coliform contribution from SSOs and leaking sewer lines will be more obvious
during typical and low periods. In a study conducted by the Piedmont Triad Council of
Governments (PTCOG) in the East Fork Deep watershed (an upper part of the Deep River
watershed), occasional exceedances of fecal coliform due to SSOs, leaking sewer lines, and
direct pipelines are predicted (NCDENR, 2004).

1.2. Water Quality Target: North Carolina Water Quality Standard.
1.2.1. Water Quality Standard for Turbidity
The North Carolina fresh water quality standard for Class WS-IV and C waters for turbidity
(T15A: 02B.0211) states:
The turbidity in the receiving water shall not exceed 50 Nephelometric Turbidity Units
(NTU) in streams not designated as trout waters and 10 NTU in stream, lakes or reservoirs
designated as trout water; for lakes and reservoirs not designated as trout waters, the
turbidity shall not exceed 25 NTU; if turbidity exceeds these levels due to natural
background conditions, the existing turbidity level cannot be increased. Compliance with
this turbidity standard can be met when land management activities employ Best
Management Practices (BMPs) recommended by the Designated Nonpoint Source Agency.
BMPs must be in full compliance with all specifications governing the proper design,
installation, operation and maintenance of such BMPs.
1.2.2. Water Quality Standard for Fecal Coliform
The North Carolina fresh water quality standard for Class WS-IV and C waters for fecal coliform
(T15A: 02B.0211) states:
Organisms of the coliform group: Fecal coliforms shall not exceed a geometric mean of
200/100mL (MF count) based upon at least five consecutive samples examined during any
30-day period, nor exceed 400/100mL in more than 20 percent of the samples examined
during such period; violations of the fecal coliform standard are expected during rainfall
events and, in some cases, this violation is expected to be caused by uncontrollable nonpoint
source pollution; all coliform concentrations are to be analyzed using the membrane filter
technique unless high turbidity or other adverse conditions necessitate the tube dilution
method; in case of controversy over results, the MPN 5-tube dilution technique will be used
as the reference method.

1.3. Water Quality Monitoring
The DWQ monitored water quality parameters which include fecal coliform, total suspended
solids (TSS), and turbidity, in the three water bodies: Haw River, Deep River, and Dan River.
The ambient stations – B1140000 near NC Hwy 49, B4615000 near Randleman, and N2300000
near Wentworth – were responsible for the 303(d) listing of a portion of the three water bodies
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
15
respectively (Figures 1.1 and 1.2). The DWQ monitored the three ambient stations regularly
from January 1997 through March 2004 (Appendix 11.1). The water samples were collected
monthly for water quality assessment. A summary of the fecal coliform and turbidity data
collected is presented in Table 1.2.

The Upper Cape Fear River Basin Association (UCFRBA) monitored the Third Fork Creek at
the coalition station B3025000 at Hwy 54 (Figure 1.1). The association collected water samples
monthly for the period from April 26, 2002 through September 25, 2003 to examine water
quality parameters, which include fecal coliform, TSS, and turbidity. A summary of the fecal
coliform and turbidity data collected in the coalition stations is also presented in Table 1.2.

able 1.2: Summary of water quality monitoring for turbidity and fecal coliform
impairment.
Water Bodies/
Parameters
Sampling
periods
Number
of samples
collected
Number
greater
than
standard
Exceeding
percentage
Responsible
organization
1. Haw River
Fecal Coliform
Fecal coliform
Turbidity
2. Deep River
Fecal Coliform
3. Third Fork Creek
Turbidity
4. Dan River
Turbidiy

1/97 – 9/03
5/02 – 7/02
1/97 – 9/03

1/97 – 9/03

4/00 – 9/03

2/97 – 3/04

80
12
73

72

42

78

21 a
0 b
8 c

17 a

5

12

26
0
11

24

12

15

DWQ
DWQ
DWQ

DWQ

UCFRBA

DWQ
a Instataneous fecal coliform measurement > 400 counts/100ml.
b 30-day Geometric mean of fecal coliform measurements > 200 counts/100ml.
c Turbidity measurements > 50 NTU.

1.3.1. Turbidity
The instantaneous data suggest that the turbidity level exceeded 50 NTU in more than 10%
during the study period at the sites, B1140000, B3025000, and N2300000, in the Haw River,
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
16
Third Fork Creek, and Dan River respectively (Table 1.2). It appears that there were occasional
excursions of turbidity above the water quality standards.
1.3.2. Fecal Coliform
The DWQ launched an additional intensive fecal coliform monitoring program in the Haw River
from May 21, 2002 through July 9, 2002 to assess the impairment status with regards to the
standards specification requiring five samples per 30-day period. A total of 12 samples were
collected during the period (Table 1.2). The data was utilized to estimate the 30-day geometric
mean to examine whether fecal coliform exceeded the water quality standard, 200 counts /100
mL, at the ambient station, B1140000. None of the geometric means of fecal coliform exceeded
the water quality standard (Figure 1.8).

Figure 1.8. Rolling 30-day geometric mean of observed fecal coliform concentration in the Haw
River at station B1140000.

Although the geometric mean of fecal coliform did not exceed 200 counts / 100ml at the ambient
sites, B1140000, in the Haw River, the instantaneous data did, however, suggest that the fecal
0
20
40
60
80
100
120
140
6/3/2002 6/13/2002 6/23/2002 7/3/2002 7/13/2002 7/23/2002 8/2/2002
Dates
Fe
c
a
l

c
o
l
i
f
o
r
m

(
C
o
u
n
t
s
/
1
0
0

m
l
)
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
17
colifrom concentration exceeded 400 counts / 100ml in more than 20 % of the samples examined
during January 1997 through September 2003 (Table 1.2).

Similar to the Haw River, the fecal coliform concentration also exceeded 400 counts / 100ml in
more than 20 % of the samples examined at B4615000 in the Deep River. However, an
additional intensive fecal coliform monitoring program with regards to the standards
specification requiring five samples per 30-day period was not launched in the Deep River due to
limitation in time. Therefore, evaluation of fecal coliform contamination in terms of geometric
mean was not conducted for the Deep River.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
18
2. General Source Assessment
Generally, sources of fecal coliform and turbidity may be point or non-point in nature. Point
sources are typically those regulated under the National Pollution Discharge Elimination System
(NPDES) program. Non-point sources are diffuse sources that typically cannot be identified as
entering a water body at a single location. Following sections describe point and non-point
sources of turbidity and fecal coliform.

2.1. General Sources of Turbidity
Turbidity is a measure of the cloudiness of water. In a water body, the cloudiness can be
enhanced due to silt and clay from watershed and stream erosion, organic detritus from streams
and wastewater, and phytoplankton growth. In this study, turbidity is measured in the
Nephelometric Turbidity Unit (NTU) and is significantly correlated with total suspended solid
(TSS). The relationship between Turbidity and TSS is discussed below.
2.1.1. Non-point Sources of Turbidity
Potential sources of turbidity from non-point sources are forests, agricultural lands, construction
sites, urban runoff, and stream channel erosion. Surface runoff is the main carrier of sediments
from forests, agricultural land, and construction sites. Normally, runoff flowing through natural
stands, where there are not any land disturbing operations being conducted, carries insignificant
amount of sediments. However, when runoff passes through logging and harvesting sites,
plantation sites, and site preparation sites, the runoff would carry significant amount of sediment,
thereby increasing turbidity in a stream. Similarly, runoff flowing through agricultural land can
carry substantial amount of sediments. The amount of sediment depends on erodability of soils,
types of agricultural practices, crop type and density, rainfall intensity, and existence and type of
agricultural BMPs.

Moreover, the amount of sediment load in runoff flowing through constructed site would be
substantially higher than in runoff flowing through forests and agricultural land when erosion
controls are not properly maintained or required. At a construction site, vegetation cover is lost
and soil surface is often disturbed. As a result, the site becomes more exposed to rainfall, and
thus increases the probability of rill and gully erosion to occur. The DWQ staff noticed several
developing activities such as land clearing and site preparation for residential buildings,
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
19
commercial areas, roads, and highways being conducted in the Haw River and Third Fork Creek
watersheds.

Urbanization also increases the amount of sediment transported to receiving waters. Impervious
urban landscapes like roads, bridges, parking lots, and buildings prevent rainwater to quickly
percolate into ground. In the impervious lands, rainwater remains above the surface, gathers
sediments and solid materials, and runs off in large amounts.

In addition, municipalities install storm sewer systems that quickly channel the urban runoff
from roads and other impervious surfaces. Urban runoff increases its velocity once it enters the
storm sewer system. When it leaves the system and empties into a stream, large volumes of
quickly flowing runoff erode stream banks, damage streamside vegetation, and widen stream
channels.
2.1.2. Point Sources of Turbidity
Point sources are distinguished from nonpoint sources in that they discharge directly into streams
at a discrete point. Point sources of turbidity consist primarily of large and small industries,
wastewater-treatment plants, and Municipal Separate Storm Sewer System (MS4).
As authorized by the Clean Water Act, the DWQ regulates the National Pollutant Discharge
Elimination System (NPDES) permit program to control water pollution due to point sources.
Individual homes that are connected to a municipal system, use a septic system, or do not have a
surface discharge do not need an NPDES permit; however, industrial, municipal, and other
facilities must obtain permits if their discharges go directly to surface waters.

2.1.2.1. NPDES-Regulated Municipal and Industrial Wastewater Treatment Facilities
Discharges from wastewater treatment facilities may contribute sediment to receiving waters as
total suspended solids (TSS) and/or turbidity. Municipal treatment plants and industrial treatment
plants are required to meet surface water quality criteria for turbidity in their effluent. When
effluent turbidity concentrations exceed surface water quality criteria, and result in permit
violations, action will be taken through the NPDES unit of North Carolina’s Division of Water
Quality.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
20
2.1.2.2. NPDES General Permits
General permitted facilities, while not subject to effluent TSS, or turbidity limitations, are
required to develop a storm water pollution prevention plan, and conduct qualitative and/or
quantitative measurements at each storm water discharge outfall and vehicle maintenance area.
Sampling methodology and constituents to be measured are characteristic of the volume and
nature of the permitted discharge. For example, general permits for mining operations require the
permitee to measure settleable solids, total suspended solids, turbidity, rainfall, event duration,
and flow in storm water discharge areas. Measurements of pH, oil and grease, total suspended
solids, rainfall, and flow are required in on-site vehicle maintenance areas. Similarly, monitoring
is required in mine dewatering areas, wastewater associated with sand/gravel mining, and in
overflow from other process recycle wastewater systems.

2.1.2.3. Municipal Separate Storm Sewer System (MS4)
A recent EPA mandate (Wayland, 2002) requires NPDES permitted storm water to be placed in
the waste load allocation (WLA), which was previously reserved for continuous point source
waste loads. In 1990, EPA promulgated rules establishing Phase I of the NPDES storm water
program. The Phase I program for Municipal Separate Storm Sewer System (MS4) requires
operators of medium and large MS4s, which generally serve populations of 100,000 or greater,
to implement a storm water management program as a means to control polluted discharges from
these MS4s.

2.2. General Sources of Fecal Coliform
Both point sources and non-point sources may contribute fecal coliform to the water bodies.
Potential sources of fecal coliform loading are discussed below.
2.2.1. Non-point Sources of Fecal Coliform
Fecal coliform from non-point sources include those sources that cannot be identified as entering
the water body at a specific location. Non-point source pollution can include both urban and
agricultural sources, and human and non-human sources (Table 2.1). The non-point sources of
fecal coliform in the water bodies include wildlife, livestock (land application of agricultural
manure and grazing), urban development (stormwater runoff, including sources from domestic
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
21
animals), failing septic systems, and sewer line systems (illicit connections, leaky sewer lines
and sewer system overflows).

Table 2.1. Potential Source of Fecal Coliform Bacteria in Urban and Rural Watersheds.
(Source: Center for Watershed Protection, 1999)
Source Origin Type Source
Human Sources Sewered watershed Combined sewer overflows
Sanitary sewer overflows
Illegal sanitary connections to
storm drains
Illegal disposal to storm drains
Non-sewered watershed Failing septic systems
Poorly operated package plant
Landfills
Marinas
Non-human Sources Domestic animals and
urban wildlife
Dogs, cats
Rats, raccoons
Pigeons, gulls, ducks, geese
Livestock and rural wildlife Cattle, horse, poultry
Beaver, muskrats, deer,
waterfowl
Hobby farms

2.2.1.1. Land Use Contribution
Agricultural land alongside a stream would contribute fecal coliform from livestock and manure
applications. In addition, when cattle have direct access to streams, feces may be deposited
directly into a stream.

Runoff from urban surface is also a potentially significant source of fecal coliform loadings.
Urban lands may contribute fecal coliform from pets such as dog and cats. In a study conducted
by Hyer et al., 2001, the bacterial loads due to dog waste accounted for nearly 10 percent of the
total bacterial load in three creeks of Virginia: Accotink Creek, Blacks Run, and Christians
Creek.

Furthermore, wildlife faces in runoff may be a frequent source of fecal coliform loading where
forest dominates the streamside.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
22
2.2.1.2. Urban Development/Sanitary Sewer Overflows/WWTP Residual Land Application
Fecal coliform can originate from various urban sources. These sources include pet waste,
runoff through stormwater, sewers, illicit discharges/connections of sanitary waste, leaky sewer
systems, and sewer system overflows.

Fecal coliform contamination can be profound when sewer pipes are clogged or flooded by
stormwater. Infiltration of rainfall can enter the sewer system through cracks and leaks in pipes.
This additional flow volume, in combination with the existing sewer flow, can exceed the
capacity of the system resulting in a sanitary-sewer-overflow (SSO).

2.2.2. Point Sources of Fecal Coliform
Point sources of fecal coliform consist primarily of large and small industries, wastewater-
treatment plants, and Municipal Separate Storm Sewer System (MS4). As authorized by the
Clean Water Act, the DWQ regulates the National Pollutant Discharge Elimination System
(NPDES) permit program to control water pollution due to point sources. Individual homes that
are connected to a municipal system, use a septic system, or do not have a surface discharge do
not need an NPDES permit; however, industrial, municipal, and other facilities must obtain
permits if their discharges go directly to surface waters.

2.2.2.1. NPDES-Regulated Municipal and Industrial Wastewater Treatment Facilities
Discharges from wastewater treatment facilities may contribute fecal coliform to receiving
waters. Municipal treatment plants and industrial treatment plants are required to meet surface
water quality criteria for fecal coliform in their effluent. When effluent turbidity concentrations
exceed surface water quality criteria, and result in permit violations, action will be taken through
the NPDES unit of North Carolina’s Division of Water Quality.

2.2.2.2. NPDES General Permits
General permitted facilities are required to develop a pollution prevention plan to discharge
domestic wastewaters from single family residences and other domestic discharges. The
permitted flow of these facilities may not in any case exceed 1000 gallon per day. The facilities
require to measure BOD5, total suspended residue, fecal coliform, and total residual chlorine.
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
23
The facilities must monitor the pollutants every year and document the following maintenance
activities:
• Septic tanks shall be maintained at all times to prevent seepage of sewage to the ground.
• Septic tanks will be checked at least yearly to determine if solids must be removed or if
other maintenance is necessary.
• Septic tanks shall be pumped out within three to five years of the issuance date on the
Certificate of coverage.
• Contents removed from septic tanks shall be disposed at a location and in a manner
compliant with all local and state regulations.
• Surface sand filters, disinfection apparatus and (if applicable) dechlorination apparatus
shall be inspected weekly to confirm proper operation.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
24
3. Haw River Impairment

3.1. Source Assessment
3.1.1. NPDES Wastewater Permits
There were 24 facilities that discharged wastewater continuously to the polluted portion of the
Haw River and tributaries under the NPDES program (Table 3.1). Nine out of 24 facilities
discharged wastewaters directly to the Haw River (Appendix 11.2). In general, privately own
facilities were permitted to discharge daily up to 45 mg/L of TSS and 400 counts/100mL of fecal
coliform, whereas publicly own facilities were permitted to discharge weekly average up to 45
mg/L of TSS and 400 counts/100mL of fecal coliform to the Haw River.

Table 3.1. NPDES Wastewater Permits in the Haw River
TSS (mg/L)
Fecal Coliform
(#/100mL)
Permit No. Facility Name
Permitted
Flow (MGD)Daily Permitted Limits
NC0046809 Pentecostal Holiness Church 0.02 45 400
NC0066966 Quarterstone Farm WWTP 0.16 45 400
NC0001384 Williamsburg plant 0.025 45 400
NC0045144 Western Alamance High School 0.01 45 400
NC0031607 Western Alamance Middle School 0.015 45 400
NC0046043 Oak Ridge Military Academy 0.04 45 400
NC0045161 Altamahaw/Ossipee Elementary School 0.012 45 400
NC0046019 The Summit WWTP 0.015 45 400
NC0066010 Williamsburg Elementary School 0.004 45 400
NC0003913 Altamahaw Division plant 0.15 108 lb 400
NC0065412 Pleasant Ridge WWTP 0.0235 45 400
NC0060259 Willow Oak Mobile Home Park 0.0175 135 400
NC0084778 Harvin Reaction Technology 0.11 45 400
NC0029726 Guilford Correctional Center WWTP 0.025 45 400
NC0038156 Northeast Middle & Senior High WWTP 0.032 45 400
NC0022691 Autumn Forest Manuf. Home Community 0.082 45 400
NC0001210 Monarch Hosiery Mills Incorporated 0.05 81.5 lb NA
NC0038172 McLeansville Middle School WWTP 0.0113 45 400
NC0055271 Shields Mobile Home Park 0.006 45 400
NC0073571 Countryside Manor WWTP 0.015 45 400
Weekly Average Permitted Limit
NC0023868 Eastside WWTP 12 45 400 GM
NC0024881 Reidsville WWTP 7.5 45 400 GM
NC0024325 North Buffalo Creek WWTP 16 45 400 GM
NC0047384 T.Z. Osborne WWTP 40 45 400 GM
GM = Geometric Mean
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
25
3.1.2. NPDES General Permits
All construction activities in the Haw River watershed that disturb one or more acres of land are
subject to NC general permit NCG010000 and as such are required to not cause or contribute to
violations of Water Quality Standards. As stated in Permit NCG010000, page 2, “The
discharges allowed by this General Permit shall not cause or contribute to violations of Water
Quality Standards. Discharges allowed by this permit must meet applicable wetland standards as
outlined in 15A NCAC 2B .0230 and .0231 and water quality certification requirements as
outlined in 15A NCAC 2H .0500”. Monitoring requirements for these construction activities are
outlined in Section B (page 5) of NCG010000. As stated, “All erosion and sedimentation control
facilities shall be inspected by or under the direction of the permittee at least once every seven
calendar days (at least twice every seven days for those facilities discharging to waters of the
State listed on the latest EPA approved 303(d) list for construction related indicators of
impairment such as turbidity or sedimentation) and within 24 hours after any storm event of
greater that 0.5 inches of rain per 24 hour period..” (NCG010000, Section B)

As per 40 CFR § 122.44(d)(1)(vii)(B), where a TMDL has been approved, NPDES permits must
contain effluent limits and conditions consistent with the requirements and assumptions of the
WLA in the TMDL. While effluent limitations are generally expressed numerically, EPA
guidance on NPDES-regulated municipal and small construction storm water discharges is that
these effluent limits be expressed as best management practices (BMPs) or other similar
requirements, rather than numeric effluent limits (EPA TMDL and WLA Guidance Memo,
2002). Compliance with the turbidity standard in the Haw River is expected to be met when
construction and other land management activities in the Haw River watershed employ adequate
BMPs. Upon approval of this TMDL, DWQ will notify the NC Division of Land Resources
(DLR) and other relevant agencies, including county and local offices in the Haw River
watershed responsible in overseeing construction activities, as to the impaired status of the Haw
River and the need for a high degree of review in the construction permit review process.

Similarly, all single family residences or domestic treatment facilities who discharge wastewaters
not exceeding 1000 gallons per day in the Haw River watershed are subject to NC general permit
NCG550000 and as such are required to not cause or contribute to violations of Water Quality
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
26
Standards. Monitoring requirements for these facilities are outlined in Part I (page 2) of
NCG550000 (http://h2o.enr.state.nc.us/NPDES/documents/NCG55_Permit_2002.pdf). A brief
statement of maintenance activities is presented in Section 2.2.2.2.
3.1.3. NPDES Stormwater MS4s
Within the Haw River watershed, there is one community that obtained an NPDES stormwater
permit under the first phase of federal stormwater regulations, the City of Greensboro. The
permit number for the City of Greensboro is NCS000248.

The cities of Burlington, Elon College, Gibsonville, Graham, Greenville, and Haw River are
identified under the second phase of federal stormwater regulations. The City of Reidsville is
identified as a possible candidate for the second phase of federal stormwater regulations. The
DWQ has not issued NPDES permit numbers to the cities (from personal communication with
DWQ staff, Ms. Aisha Lau).
.
The ArcView software was utilized to overlay the shape files of NC municipalities over the
USGS land use coverage (discussed in Section 1.1) in order to estimate the land coverage of the
cities under MS4 program. Approximately all urban lands in the Haw River watershed were
occupied by the cities.
3.1.4. Livestock Populations
The North Carolina Department of Agriculture (NCDA) regularly performs an agricultural
census for each county of the state. This census includes estimated livestock populations in each
county, as shown in Table 3.2 for the Haw River watershed.

The NCDA also ranks each county according to the number of animals in each particular
category. Guildford County had the 7th highest population of milk cows in 2003 and Alamance
County had the 11th highest population of chickens in North Carolina in 2002. With respect to
other animals, none of these counties ranks in the top fifteen in terms of population.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
27
Table 3.2. Estimated Livestock population in the Haw River watershed above NC 49 (NCDA).
Counties Livestock
Alamance Guilford Forsyth Rockingham Caswell
Swine (2002)
Cattle (2003)
Beef Cow (2003)
Milk Cow (2003)
Broiler (2002)
Turkey (2002)
Chickens (2002)
1.2
19.2
7.9
1.7
3,300
<500
450
8.6
16
7.0
2.0
500
<500
100
<1
7.2
3.8
<0.2
<500
<500
<50
7.6
10.9
4.7
0.7
<500
<500
<50
1.3
11.1
4.6
<0.2
<500
<500
<50
(Source: http://www.ncagr.com/stats/cntysumm/) Year of the census is reported for each type of
livestock. Counts are reported in thousands.

3.1.5. Septic Tanks
The upper Haw River watershed is a rapidly urbanizing area. Thus, most households have
connected to water and sewer services provided by municipalities. However, there are still
households that do utilize septic systems, as shown in Table 3.3.

Table 3.3. Estimated housing units using septic systems in the Haw River watershed in 2002.
County
Number of Housing
Units Number of Septic Systems
Percentage of Housing
Units with Septic Systems
Alamance 57,578 550 0.96
Guilford 189,272 687 0.36
Forsyth 138,573 436 0.31
Rockingham 41,129 540 1.31
Caswell 9,899 226 2.28
Source for housing unit:
http://www.deh.enr.state.nc.us/oww/Program_improvement_team/Pit_Index.htm
Source for septic system:
http://quickfacts.census.gov/qfd/states/

In the City of Greensboro, residents are required to switch from septic to sewer systems within 5
years of the sewer line extension. Recently, Greensboro sewer lines were extended throughout a
large portion of the watershed area.
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
28

3.2. Technical Approach
Based on the above initial data analysis, it appears that both point sources and non-point sources
contributed fecal coliform and turbidity in the Haw River. Because the magnitude of fecal
coliform and turbidity in a water body associates with flow condition, a load duration approach is
adopted for this study. This approach determines impairment loads under different flow
conditions – high flow, transition flow, typical flow, and low flow – to identify source types,
specify assimilative capacity of a stream, and to estimate magnitude of load reduction required to
meet the water quality standard. The methodology used to develop a load duration curve is
based on Cleland (2002).
3.2.1. Endpoint for Turbidity
As discussed in Section 2.1, turbidity is a measure of cloudiness and is reported in
Nephelometric Turbidity Units (NTU). Therefore, turbidity is not measured in terms of
concentrations and cannot be directly converted into loadings required for developing a load
duration curve. For this reason, total suspended solid (TSS) was selected as a surrogate measure
for this study.

In order to observe relationship between TSS and turbidity in the Haw River, a regression
equation between the two parameters was developed using the observed data collected from
January 1997 through September 2003 in the ambient station, B1140000, near Haw River. The
relationship is shown in Equation 3.1. The coefficient of determination (R-Square) between the
two parameters was 0.57; therefore, a moderate relationship between the two parameters was
experienced.

Y = 3.9327e 0.0432 X R-Square = 0.57 ----------------------(3.1)

Where, Y = TSS in mg/l and X = turbidity in NTU.

Equation 3.1 suggests that the Haw River yielded approximately 3.93 mg/L of TSS during
natural condition (NTU = 0). The river, however, increased exponentially TSS by 0.043 mg/L
for each turbidity increase. Therefore, the corresponding TSS value at the turbidity standard of
50 NTU was 34 mg/L.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
29
3.2.2. Endpoint for Fecal Coliform
The TMDL objectives require the instream fecal coliform concentrations to meet both the
instantaneous standard of 400 counts /100mL and the geometric mean standard of 200 counts /
100mL. As discussed in Section 1.3.2, the Haw River does not seem to be contaminated due to
fecal coliform when the river is evaluated with regards to the geometric mean standard.
Therefore, only the instantaneous standard is considered to be the endpoints for the
determination of the fecal colifrom TMDL for the river.

3.2.3. Flow Duration Curve
Development of flow duration curve is the first step of load duration approach. A flow duration
curve employs a cumulative frequency distribution of measured daily stream flow over the
period of record. The curve relates flow values measured at the monitoring station to the percent
of time the flow values were equaled or exceeded. Flows are ranked from lowest, which exceed
nearly 100 percent of the time, to highest, which exceed less than 1 percent of the time.

Reliability of the flow duration curve depends on the period of record available at monitoring
stations. Predictability of the curve increases when longer periods of record are used. For that
reason, daily stream data collected from January 1928 through September 2003 at the USGS
gage station, 02096500, near Haw River, was utilized to develop flow duration curves. The flow
duration curve is shown in Figure 3.1. Flow statistics as generated by the curves are presented in
Table 3.4.

Table 3.4: Flow Statistics for the four water bodies.
High Flow
(< 10th percentile)
Transitional Flow
(Between 10th and 30th
percentile)
Typical Flow
(Between 30th and 90th
percentile)
Low Flow
(> 90th percentile)
1270 – 42000 cfs 179 – 1270 cfs 100 – 179 cfs 5 – 100 cfs

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
30

Figure 3.1. Flow Duration Curve for the Haw River at USGS 02096500.

The above flow duration curve was used to determine the seasonality and flow regimes during
which the exceedances of the pollutants occurred. It was also used to determine maximum daily
pollutant load based on the flow duration and applicable standard. The applications of the flow
duration curve for the Haw River are discussed in the following paragraphs.
3.2.4. Load Duration Curve
A load duration curve is developed by multiplying the flow values along the flow duration curve
by the pollutant concentrations and the appropriate conversion factors. As seen in Figure 3.2,
allowable and existing loads are plotted against the flow recurrence interval. The allowable load
is based on the water quality numerical criteria, margin of safety, and flow duration curve. The
target line is represented by the line drawn through the allowable load data points and hence, it
determines the assimilative capacity of a stream or river under different flow conditions. Any
values above the line are exceeded loads and the values below the line are acceptable loads.
Therefore, a load duration curve can help define the flow regime during which exceedances
occur. Exceedances that occur during low-flow events are likely caused by continuous or point
1
10
100
1000
10000
100000
0.
0
0
5
%
0.
0
1
0
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0.
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0
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0
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.
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.
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20
.
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25
.
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30
.
0
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35
.
0
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40
.
0
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45
.
0
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50
.
0
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55
.
0
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60
.
0
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.
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.
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75
.
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.
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.
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95
.
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99
.
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Percent flow exceeded
Fl
o
w

(
c
f
s
)
Trans.
Flow
Typical Flow Low
Flow
High
Flow
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
31
source discharges, which are generally diluted during storm events. Exceedances that occur
during high-flow events are generally driven by storm-event runoff. A mixture of point and non-
point sources may cause exceedances during normal flows.

Following paragraphs discuss procedures to estimate endpoints for turbidity and fecal coliform in
the Haw River in order to identify assimilative capacity of the river in each flow condition and to
identify the flow regime during which exceedances occur.

3.2.4.1. Turbidity Assimilative Capacity
Existing TSS loads to the Haw River were determined by multiplying the observed TSS
concentration by the flow observed on the date of observation and converting the result to daily
loading values. The assimilative capacities of the water bodies were determined by multiplying
the TSS concentration that is equivalent to a turbidity value of 50 NTU by the full range of
measured flow values. Figures 3.2 presents the calculated load (scatter plot), power line (dotted
line), and TMDL target loading (solid line) for the river.

Figure 3.2. TSS Load duration curve for the Haw River at the ambient station, B1140000, from
January 1997 through September 2003.

0.1
1.0
10.0
100.0
1000.0
10000.0
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent flow exceeded
TS
S

(
t
o
n
s
/
d
a
y
)
Allowable Load Existing Load
Summer Existing Load Power (Existing Load)
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
32
The assimilative capacity exceeded primarily during high-flows (< 10% of flow exceedance) and
transitional-flows (10% –30% flow exceedance) in the Haw River. There was no TSS
exceedance during typical-flows (30% - 90% flow exceedance) and low-flows (>90% flow
exceedance). As evidenced by high loads during high and transitional flows suggest that the
sources of turbidity could be from storm runoff and/or bank erosion. During the flow periods,
runoff would carry a substantial amount of sediments and solid materials from impermeable as
well as permeable land surfaces. The runoff can even transport the materials even from a far
way lands.

Bank erosion may be another result of high and transitional flows. When high volume and
velocity runoff exceeds the resistance of the lateral (side) soil material, bank erosion occurs.
Because soils in the Haw River watershed are sandy clay loam and clay loam, which contain
considerable proportion of clay and silt (Soil Survey of Guildford County, NC, 1977), bank
erosion often causes high flocculation of clay and silt, thereby creating high turbidity in the river.

Furthermore, TSS load under natural background condition stayed under the turbidity standard of
50 NTU (34 mg/L) in the Haw River. The result was clearly explicated when a power line that
represented average TSS loads under different flow conditions was drawn (Figure 3.2). The
power line passed underneath the targeted line except during high flow period (<10% flow
exceeded). The loads during high flow period is however unmanageable and hence is excluded
in the TMDL estimation in this study.

3.2.4.2. Fecal Coliform Assimilative Capacity
The fecal coliform assessment also used the load duration curve approach to determine existing
load and assimilative capacity. As stated in Section 3.2.2, analysis was performed for the
instantaneous standard of 400 counts / 100mL to determine the most conservative measure of
impairment. Figures 3.3 present the calculated loads and the TMDL target loadings for the fecal
coliform.

In the Haw River, the criteria violations seem to have occurred at both high and low flows,
suggesting that contamination due to fecal coliform occurred during both wet and dry weather
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
33
conditions (Figure 3.3). As evidenced by high fecal coliform concentrations during dry
weather/low flow, it seems that the sources of fecal coliform were near the Haw River itself.
Furthermore, as evidenced by high concentrations during high flows, it seems that the sources
were also far away from the river. Therefore, the results indicate that the combination of sewer
pipe leakage, failing septic system, and direct pipeline had elevated the fecal coliform during dry
weather/low flow in the river. Correspondingly, non-point sources and sporadic sources such as
sanitary sewer overflows had elevated the fecal coliform during high flows.

Figure 3.3. Fecal coliform load duration curve for the Haw River at the ambient station,
B1140000, from January 1997 through September 2003.

3.3. Total Maximum Daily Loads (TMDL)
Sections 3.2 described the processes and rationale to identify the endpoints, assimilative
capacity, potential sources, and target loadings for each pollutant in the Haw River watershed.
These efforts formed the basis for the TMDL process. Following sections describe the key
components required by the TMDL guidelines to set the final TMDL allocation for the
Watershed.

Total Maximum Daily Load (TMDL) can be defined as the total amount of pollutant that can be
assimilated by the receiving water body while achieving water quality standards. A TMDL can
1.00E+10
1.00E+11
1.00E+12
1.00E+13
1.00E+14
1.00E+15
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent flow exceeded
Fe
c
a
l

(
C
o
u
n
t
s
/
d
a
y
)
Allowable Load Existing Load Summer Existing Load
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
34
be expressed as the sum of all point source loads (WLAs), non-point source loads (LAs), and an
appropriate margin of safety (MOS), which takes into account any uncertainty concerning the
relationship between effluence limitations and water quality. This definition can be expressed by
equation 3.2:

TMDL = ∑WLAs + ∑LAs + MOS ---------------(3.2)

The objective of the TMDL is to estimate allowable pollutant loads and to allocate the known
pollutant source in the watershed in order to implement control measures and to achieve water
quality standards. The Code of Federal Regulations (40 CFR § 130.2 (1)) states that TMDLs can
be expressed in terms of mass per time, toxicity, or other appropriate measures. For TSS
(surrogate measure for turbidity) and fecal coliform contamination, TMDLs are expressed as
tons per day and counts per 100 milliliter respectively. The TMDLs represent the maximum
one-day load the stream can assimilate and maintain the water quality criterion.

Load duration curve approach was utilized to estimate the TMDL for TSS and fecal coliform.
The systematic procedures adopted to estimate TMDLs are described below.
3.3.1. Margin of Safety (MOS)
Conceptually, the MOS is included in the TMDL estimation to account for the uncertainty in the
simulated relationship between the pollutants and the water quality standard. In this study, the
MOS was explicitly included in following TMDL analysis by setting the TMDL target at 10
percent lower than the water quality target for turbidity and fecal coliform.

3.3.2. Target Reduction

3.3.2.1. Turbidity
To determine the amount of turbidity reduction necessary to comply with the water quality
criteria, exceedances of the estimated standard (34 mg TSS/L) were identified within the 10th to
95th percentile flow recurrence range. Because the assimilative capacity of the Haw River
exceeded primarily during transitional-flow periods (between 10th and 30th percentile) (Figure
3.4), a valid power curve for existing violated loads could not be estimated from the observed
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
35
data. Therefore, a simple arithmetic mean of the exceedances was used as an estimate of the
existing violated load. The allowable loads for each exceedance were calculated based on the
TMDL target value, which include the 10 percent MOS. The target curve based on the allowable
loads and the exceedances used for the existing load are shown in Figure 3.4. The estimates of
load reduction are presented in Appendix 11.3. A 61 percent reduction in TSS load is required in
order to meet the water quality standard, which in tern accounts for the 10 percent margin of
safety.

Figure 3.4. Load duration curve allowable TSS load and existing total TSS load violation in the
Haw River.

3.3.2.2. Fecal Coliform
The reduction for the instantaneous fecal coliform standard was estimated with the observed data
that exceeded the applicable water quality standard (400 counts / 100 mL) within the 10th to 95th
percentile flow recurrence range. The reduction for the geometric mean was not estimated,
because fecal coliform violation at the water quality standard, 200 count / 100 mL, was not
observed (see §1.3.2).

Unlike in turbidity, the criteria violations seem to have occurred at both high and low flows in
the Haw River. A power curve equation for the data point violating the water quality criterion
1.0
10.0
100.0
1000.0
10% 30% 50% 70% 90%
Percent Flow Exceeded
Allowable load with MOS Existing load violation
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
36
was estimated. The equation is presented in Equation 3.3. The coefficient of determination, R-
Square, for the equation is 0.60; thus suggesting a reasonable fit of the equation.

Y = (2E+12) * X (-1.6432) R-Square = 0.60 -------------------------------(3.3)
Where, Y = fecal coliform (Counts/100mL) and X = Percent Flow Exceeded.

To present the TMDLs as a single value, the existing load was calculated from the power curve
equation as the average of the load violations occurring when the flow (or load) exceeded at a
frequency greater than 10 percent and less than 95 percent. Additionally, the average load was
calculated by using percent flow exceedance in multiple of 5 percent.

The allowable loadings for each exceedance were calculated from the TMDL target value, which
includes the 10 percent MOS. The target curve based on the allowable load and the power curve
based on the exceedances are shown in Figure 3.5.

Figure 3.5. Load duration curve showing allowable and existing loads of fecal coliform in the
Haw River.

The necessary percent reduction was calculated by taking a difference between the average of the
power curve load estimates and the average of the allowable load estimates. For example, at
1.00E+11
1.00E+12
1.00E+13
1.00E+14
1.00E+15
0.000% 20.000% 40.000% 60.000% 80.000% 100.000%
Percent flow exceeded
Fe
c
a
l

c
o
l
i
f
o
r
m

(
c
o
u
n
t
s
/
d
a
y
)
Allowable Load Existing Load Voilation
Power (Existing Load Voilation)
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
37
each recurrence interval between 10 and 95 (again using recurrence intervals in multiple of 5),
the equation of the power curve was used to estimate the existing load. The allowable load was
then calculated in a similar fashion by substituting the allowable load curve. The estimated
values are given in Appendix 11.3. The estimated average fecal coliform loads were 1.144E+13
counts per day and 3.35E+12 counts per day for the power curve and allowable load curve,
respectively. This equates to an average 77 percent reduction in load.
3.3.3. TMDL Allocation
As identified by the above load duration curve method, significant amounts of TSS and fecal
coliform are required to be reduced in the Haw River. A summary of reductions required is
provided in Table 3.5.

Table 3.5. Reduction Required for TSS and Fecal Coliform
Pollutants Target with
MOS
Existing Load Allowable Load Reduction
Required
I. TSS1
II. Fecal Coliform2
< 31 mg/L
< 360 #/100mL
183.16 tons/day
1.44E+13 #/day
71.26 tons/day
3.35E+12 #/day
61 %
77 %
1 TSS is used as a surrogate variable for turbidity
2 Instantaneous measurement of fecal coliform is used.

In order to meet the TMDL objectives, the reduction should be distributed over both point and
non-point sources. A further analysis is, therefore, required to determine the breakdown between
point source and non-point source loadings.

3.3.3.1. Waste Load Allocation (WLA)
All TSS and fecal coliform transported from the wastewater facilities and the MS4 areas were
assigned to the WLA components. The relative loading rates from the facilities are listed in
Table 3.1. The relative loading rates from the MS4 areas were determined based on the report by
USGS, 1999. The report describes TSS and fecal coliform transports under different land use
conditions in the City of Charlotte and Mecklenburg County, North Carolina. A summary of the
report and a description of method that was used to estimate relative percent contribution of TSS
and fecal coliform from the urban and rural sources for this study are presented in Appendix
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
38
11.4. The estimated relative percent contribution from the MS4 and rural areas (non-point
sources including non-MS4 area) are presented in Table 3.6.

Table 3.6. Relative TSS and Fecal Coliform Contribution Rates for the Haw River.
Pollutants Load from MS4 areas (%) Load from other areas (%)
I. TSS
II. Fecal Coliform
13
19
87
81

The assimilative capacity determined in Section 3.2.4 was split based on the relative
contributions presented in Table 3.6 to determine the allocation for the MS4 areas. The results of
these calculations are summarized in Table 3.7.

The WLA associated with construction and other land management activities, as discussed in
Section 3.1.2, is equivalent to the surface water quality standard for turbidity in that any
construction activity cannot cause or contribute to a violation of the water quality standard. As
discussed, these WLAs are and will be expressed as BMPs in the general or individual
constriction permits rather than as numeric effluent limits.

3.3.3.2. Load Allocation (LA)
All TSS and fecal coliform loadings from non-point sources such as non-MS4 urban land,
agriculture land, and forestlands are reported as LAs. The relative loading rates from these areas
were determined using the similar procedures as described in Section 3.3.3.1 (See also Appendix
11.4). The estimated relative percent contribution of TSS and fecal coliform from the non-point
sources are presented in Table 3.7.

The assimilative capacity determined in Section 3.2.4 was split based on the relative
contributions presented in Table 3.6 to determine the allocation for the non-point sources. The
results of these calculations are summarized in Table 3.7.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
39
Table 3.7. Estimated TMDL and Load Allocation for TSS and Fecal Coliform for the Haw River
Watershed.
Pollutants Existing
Load
Construct-
ion
Activities
NPDES MS4

WLA1 LA MOS TMDL
I. TSS
(tons/day)

II. Fecal
Coliform
(#/day)
183.16

1.44E+13

50 NTU

NA
13.05

1.15E+12

9.26

6.37E+11

22.31

1.79E+12

48.95

1.56E+12

Explicit
10 %

Explicit
10 %
71.26

3.35E+12

1WLA = MS4 + NPDES (including construction activities)

3.3.3.3. Study Limitation
The available land cover for this study is outdated and fails to represent current land use
condition. Therefore, the estimation of WLA in Table 3.7 is not authoritative. The estimation
helps to provide understanding of the relative loads and should be viewed in light of the limited
data available to quantify the actual contributions from each individual source. The primary
focus of efforts to minimize future impairment should focus on the percent reductions and
control of sources identified in the Source Assessment (see § 2).
3.3.4. Critical Condition and Seasonal Variation
Critical conditions are considered in the load curve analysis by using an extended period of
stream flow and water quality data, and by examining the flows (percent flow exceeded) where
the existing loads exceed the target line.

Seasonal variation is considered in the development of the TMDLs, because allocation applies to
all seasons. In the load duration curves, the black mark inside a square box indicates pollutant
transport during summer period.

According to the load duration curve (Figure 3.2), the greatest frequency of exceedances of
turbidity occurred during high-flow periods throughout the season. The result shows that wet
weather under high-flow period is the critical period for turbidity in the Haw River.

However, the existing load violation for fecal coliform occurred at all flow conditions throughout
the season (Figure 3.3). Therefore, both dry and wet weathers are critical for fecal coliform.
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
40
4. Deep River Impairment

4.1. Source Assessment
4.1.1. NPDES Wastewater Permits
There were about 5 facilities that discharged wastewater continuously to the polluted portion of
the Deep River and tributaries under the NPDES program (Table 4.1). The facilities were
permitted to discharge up to 400 counts/100mL of fecal coliform daily. However, none of the
facilities discharged wastewaters directly to the river (Appendix 11.2).

Table 4. 1. NPDES Wastewater Permits in the Deep River
Permit No. Facility Name
Permitted Flow
(MGD)
Daily Permitted Limits
Fecal Coliform (#/100mL)
NC0038091 Southern Elementary School 0.0075 400
NC0038229 Southern Guilford High School 0.012 400
NC0055255 Crown Mobile Home Park 0.042 400
NC0041483 Plaza Mobile Home Park 0.003 400
Weekly Average Permitted Limits
NC0024210 East Side WWTP 26 400 GM
GM = Geometric Mean

4.1.2. NPDES General Permits
All single family residences or domestic treatment facilities who discharge wastewaters not
exceeding 1000 gallons per day in the Deep River watershed are subject to NC general permit
NCG550000 and as such are required to not cause or contribute to violations of Water Quality
Standards. Monitoring requirements for these facilities are outlined in Part I (page 2) of
NCG550000 (http://h2o.enr.state.nc.us/NPDES/documents/NCG55_Permit_2002.pdf). A brief
statement of maintenance activities is presented in Section 2.2.2.2.

4.1.3. NPDES Stormwater MS4s
Within the Deep River watershed, there is one community that obtained an NPDES stormwater
permit under the first phase of federal stormwater regulations, the City of Greensboro. The cities
of High Point and Archdale are identified under the second phase of federal stormwater
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
41
regulations. The DWQ has not issued NPDES permit numbers to these cities except to the City
of Greensboro. The permit number for the City of Greensboro is NCS000248.

The ArcView software was utilized to overlay the shape files of NC municipalities over the Deep
River watershed (discussed in Section 1.1) in order to estimate the land coverage of the MS4
areas. All of the urban lands in river were identified for the MS4 programs.
4.1.4. Livestock Populations
The North Carolina Department of Agriculture (NCDA) regularly performs an agricultural
census for each county of the state. This census includes estimated livestock populations in each
county, as shown in Table 4.2 for the Deep River watershed.

Table 4.2. Estimated Livestock population in the Deep River watershed above Randleman
(NCDA).
Counties Livestock
Guilford Forsyth Randolph
Swine (2002)
Cattle (2003)
Beef Cow (2003)
Milk Cow (2003)
Broiler (2002)
Turkey (2002)
Chickens (2002)
8.6
16
7.0
2.0
500
<500
100
<1
7.2
3.8
<0.2
<500
<500
<50
34
39.1
16.9
4.4
54,300
<500
1,200
(Source: http://www.ncagr.com/stats/cntysumm/) Year of the census is reported for
each type of livestock. Counts are reported in thousands.

4.1.5. Septic Tanks
Some residences in the Deep River watersheds use septic tanks. A majority of the residents
seem to be connected to sewer systems (Table 4.3).

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
42
Table 4.3. Estimated housing units using septic systems in the Deep River watershed in 2002.
County
Number of Housing
Units Number of Septic System
Percentage of Housing
Units with Septic Systems
Guilford 189,272 687 0.36
Forsyth 138,573 436 0.31
Randolph 56,701 853 1.50
Source for housing unit:
http://www.deh.enr.state.nc.us/oww/Program_improvement_team/Pit_Index.htm
Source for septic system:
http://quickfacts.census.gov/qfd/states/

The Eastern portion of the Deep River, where the City of High Point is located, has the highest
population density. The majority of the housing units were connected to the sewer system in
1990, and more households have probably converted from septic to sewer disposal over the last
decade.

The Midwestern portion of the Deep River watershed includes recent expansion of High Point.
Most of the housing units in this portion are in the process of converting form septic tank to
sewer system.

4.2. Technical Approach
As discussed in Section 3.2, a load duration approach was used to identify source types, specify
assimilative capacity of a stream, and to estimate magnitude of load reduction required to meet
the water quality standard. Following paragraphs demonstrate systematic procedures to develop
a load duration curve for the Deep River.
4.2.1. Endpoint for Fecal Coliform
The TMDL objectives require the instream fecal coliform concentrations to meet both the
instantaneous standard of 400 counts /100mL and the geometric mean standard of 200 counts /
100mL. As discussed in Section 1.3.2, an additional intensive fecal coliform monitoring
program with regards to the standards specification requiring five samples per 30-day period was
not launched in the Deep River due to limitation in time. Therefore, evaluation of fecal coliform
contamination in terms of geometric mean was not conducted for the river. Only instantaneous
standard is considered to be the endpoints for the determination of the fecal colifrom TMDL for
the river.
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
43
4.2.2. Flow Duration Curve
Daily stream data collected from January 1928 through September 2003 at the USGS gage
station, 02099500, near Randleman, was used to develop flow duration curves. The flow
duration curve is shown in Figure 4.1. Flow statistics as generated by the curves are presented in
Table 4.4.

Table 4.4. Flow Statistics for the Deep River.
High Flow
(< 10th percentile)
Transitional Flow
(Between 10th and 30th
percentile)
Typical Flow
(Between 30th and 90th
percentile)
Low Flow
(> 90th percentile)
244 – 12000 cfs 29 – 244 cfs 17 – 29 cfs 1 – 17 cfs

Figure 4.1. Flow Duration Curve for the Deep River at USGS 02099500.

The flow duration curve was used to determine the seasonality and flow regimes during which
the exceedances of the pollutants occurred. It was also be used to determine maximum daily
1
10
100
1000
10000
100000
0%10%20%30%40%50%60%70%80%90%
100%
Percent Flow exceeded
Fl
o
w

(
c
f
s
)
High
Flow
Transitional
Flow
Typical Flow Low
Flow
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
44
pollutant load based on the flow duration and applicable standard. The applications of the flow
duration curve are discussed in the following paragraphs.
4.2.3. Load Duration Curve
As discussed in Section 3.2.4, a load duration curve is developed by multiplying the flow values
along the flow duration curve by the pollutant concentrations and the appropriate conversion
factors. As seen in Figure 4.2, allowable and existing loads are plotted against the flow
recurrence interval. The allowable load is based on the water quality numerical criteria, margin
of safety, and flow duration curve.

4.2.4.2. Fecal Coliform Assimilative Capacity
The fecal coliform assessment used the load duration curve approach to determine existing load
and assimilative capacity. As stated in Section 4.2.1, analysis was performed for the
instantaneous standard of 400 counts / 100mL to determine the most conservative measure of
impairment. Figures 4.2 present the calculated loads and the TMDL target loadings for the fecal
coliform.

Figure 4.2. Fecal coliform load duration curve for the Deep River at the ambient station,
B4615000, from January 1997 through September 2003.
1.00E+05
1.00E+07
1.00E+09
1.00E+11
1.00E+13
1.00E+15
0%
10
%
20
%
30
%
40
%
50
%
60
%
70
%
80
%
90
%
10
0
%
Pecent Flow Exceeded
Fe
c
a
l

C
o
l
i
f
o
r
m

(
c
o
u
n
t
s
/
d
a
y
)
Existing load Allowable load Summer Existing Load
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
45

There were no criteria violations during low flows in the Deep River (Figure 4.2). It seems that
the sources like sewer pipe leakage, failing septic system, and direct pipeline are not the
problems in the river. The criteria violations were seen to occur mostly during high and
transitional flows, suggesting that the combination of non-point and sporadic sources would be
the problem in the river.

4.3. Total Maximum Daily Loads (TMDL)
Sections 4.2 described the processes and rationale to identify the endpoints, assimilative
capacity, potential sources, and target loadings for fecal coliform in the Deep River watershed.
These efforts formed the basis for the TMDL process. The key components required by the
TMDL guidelines to set the final TMDL allocation for the watershed is defined by the equation
4.1.

TMDL = ∑WLAs + ∑LAs + MOS ---------------(4.1)
Where, WLA is waste load allocation (point source), LA is load allocation (non-point source),
and MOS is marginal of safety. Detail explanation of the equation is given in Section 3.3.
4.3.1. Margin of Safety (MOS)
The MOS was explicitly included in following TMDL analysis by setting the TMDL target at 10
percent lower than the water quality target for fecal coliform.
4.3.2. Target Reduction
The reduction for the instantaneous fecal coliform standard was estimated with the observed data
that exceeded the applicable water quality standard (400 counts / 100 mL) within the 10th to 95th
percentile flow recurrence range. The criteria violations were occurring through out the flow
regime except during low flow periods (Figure 4.3).

The existing loads at every 5th percentile flow recurrence in the Deep River were calculated from
the power curve equation (Equation 4.1). The allowable loadings were calculated from the
TMDL target value, which included the 10 percent MOS. Within the 10th to 95th percentile flow
recurrence range, the average of the two sets of loading estimates was calculated and the percent
of the existing load that exceeded the target was determined. The estimated values are presented
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
46
in Appendix 11.3. To meet the instantaneous limit and to account for the 10 percent MOS, about
75 percent reduction in fecal coliform is required. A summary of reductions required is provided
in Table 4.5.

Y = (2E+11) * X (-1.9614) R-Square = 0.66 -------------------------------(4.2)
Where, Y = fecal coliform (Counts/100mL) and X = Percent Flow Exceeded.

Table 4.5. Reduction Required for Fecal Coliform
Pollutants Target with
MOS
Existing Load Allowable Load Reduction
Required
Fecal Coliform1 < 360 #/100mL 2.47E+12 #/day 6.22E+11 #/day 75 %
1 Instantaneous measurement of fecal coliform is used.

Figure 4.3. Load duration curve showing allowable and existing loads of fecal coliform in the
Deep River

1.00E+10
1.00E+11
1.00E+12
1.00E+13
1.00E+14
10.00% 30.00% 50.00% 70.00% 90.00%
Percent Flow Exceeded
(C
o
u
n
t
s
/
d
a
y
)
Allowable load Existing Load Violation
Power (Existing Load Violation)
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
47
4.3.3. TMDL Allocation
As identified by the above load duration curve method, significant quantities of fecal coliform
are required to be reduced in the Deep River. In order to meet the TMDL objectives, the
reduction should be distributed over both point and non-point sources. A further analysis is,
therefore, required to determine the breakdown between point source and non-point source
loadings.

4.3.3.1. Waste Load Allocation (WLA)
All fecal coliform transported from the MS4 areas and wastewater facilities were assigned to the
WLA components. The relative loading rates from the MS4 areas were determined as described
in Section 3.3.3.1. The estimated relative percent contribution from the MS4 and rural areas
(non-point sources including non-MS4 area) are presented in Table 4.6.

Table 4.6. Relative Fecal Coliform Contribution Rates for the Deep River.
Pollutants Load from MS4 areas (%) Load from other areas (%)
Fecal Coliform 31 69

The assimilative capacity determined in Section 4.2.2 was split based on the relative
contributions presented in Table 4.6 to determine the allocation for the MS4 areas. The results of
these calculations are summarized in Table 4.7.

4.3.3.2. Load Allocation (LA)
All fecal coliform loadings from non-point sources such as non-MS4 urban land, agriculture and
forested lands were reported as LAs. The relative loading rates from these areas were
determined using the similar procedures as described in Section 3.3.2.1 (See also Appendix
11.3). The estimated relative percent contributions of fecal coliform from the non-point sources
are presented in Table 4.6.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
48
The assimilative capacity determined in Section 4.2.3 was split based on the relative
contributions presented in Table 4.6 to determine the allocation for the non-point sources. The
results of these calculations are summarized in Table 4.7.

Table 4.7. Estimated TMDL and Load Allocation for Fecal Coliform for the Deep River
Watershed.
Pollutants Existing
Load
NPDES MS4

WLA1 LA MOS TMDL
Fecal
Coliform
(#/day)
2.47E+12 3.95E+11 1.92E+11 5.87E+11 3.42E+10 Explicit
10 %

6.22E+11

1WLA = MS4 + NPDES

4.3.3.3. Study Limitation
The available land cover for this study is outdated and fails to represent current land use
condition. Therefore, the primary focus of efforts to minimize future impairment should focus
on the percent reductions and control of sources identified in the Source Assessment (see § 2).
4.3.4. Critical Condition and Seasonal Variation
According to the load duration curve (Figure 4.2), there were no violations due to fecal coliform
during low–flow events in the Deep River. The violation seems to occur during high-flow events
only. Therefore, wet weather is critical for fecal coliform in the Deep River.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
49
5. Third Fork Creek Impairment

5.1. Source Assessment
The DWQ staff noticed several developing activities such as land clearing and site preparation
for residential buildings, commercial areas, roads, and highways being conducted in the Third
Fork Creek watershed. These activities are the main sources of turbidity. Surface runoff carries
sediments and solids from these lands to the creek and increases turbidity level. In addition,
point sources such as waste water treatment plants (WWTP) and MS4 areas are also responsible
for TSS increment in a water body.
5.1.1. NPDES Wastewater Permits
There was only one facility, Brenntag Southeast, Inc., under the NPDES program that discharged
wastewater to the Third Fork Creek (Table 5.1). The facility was permitted to discharge up to 30
mg/L of TSS daily.

Table 5.1. NPDES Wastewater Permits in the Third Fork Creek
Permit No. Facility Name
Permitted
Flow (MGD)
Daily
Permitted
Limits
TSS (mg/L)
NC0086827 Brenntag Southeast, Inc. 0.0144 30

5.1.2. NPDES General Permits
All construction activities in the Third Fork Creek watershed that disturb one or more acres of
land are subject to NC general permit NCG010000 and as such are required to not cause or
contribute to violations of Water Quality Standards. As stated in Permit NCG010000, page 2,
“The discharges allowed by this General Permit shall not cause or contribute to violations of
Water Quality Standards. Discharges allowed by this permit must meet applicable wetland
standards as outlined in 15A NCAC 2B .0230 and .0231 and water quality certification
requirements as outlined in 15A NCAC 2H .0500”. Monitoring requirements for these
construction activities are briefly explained in Section 3.1.2.
5.1.3. NPDES Stormwater MS4s
The City of Durham in the Third Fork Creek watershed falls under the Phase I NPDES storm
water program for MS4. All of the urban lands in the watershed were, therefore, occupied by the
city.
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
50
5.2. Technical Approach
As discussed in Section 3.2, a load duration approach was adopted to determine impairment
loads under different flow conditions to identify source types, specify assimilative capacity of a
stream, and to estimate magnitude of load reduction required to meet the water quality standard.
Following paragraphs explains its application for developing turbidity TMDL for the Third Fork
Creek.
5.2.1. Endpoint for Turbidity
As discussed in Section 3.2.1, total suspended solid (TSS) was selected as a surrogate measure
for the Third Fork Creek. In order to observe relationship between TSS and turbidity in the
creek, a regression equation between the two parameters was developed using the observed data
collected from April 2004 through September 2003 in the ambient station, B3025000. The
equation is shown in Equation 5.1. The coefficient of determination between the two parameters
was 0.73, suggesting a significant relationship.

Y = 0.0068 X 2 + 0.0827X + 7.7524 R-Square = 0.73 ----------------------(5.1)

Where, Y = TSS in mg/l and X = turbidity in NTU.

Equation 5.2 suggests that the Third Fork Creek yielded approximately 7.75 mg/L of TSS during
natural condition (NTU = 0). However, the creek showed a polynomial relationship between
TSS and turbidity. Therefore, the corresponding TSS value at the turbidity standard of 50 NTU
was 29 mg/L.
5.2.2. Flow Duration Curve
Daily stream data collected from January 1982 through September 2003 at the USGS gage
station, 0209741955, at SR1100 near Glenlee, was used to develop flow duration curves. The
gage station drains about 21 sq. miles of the Northeast Creek watershed. The watershed area is
slightly bigger than the Third Fork Creek watershed (16.5 sq mi). The watershed is almost
similar in characteristic and is adjacent to the Third Fork Creek at the Eastern side. Therefore,
flows of the Third Fork Creek were estimated using “area ratio method.” In the method, the area
ratio is first estimated by dividing the area of the Third Fork Creek watershed by the area of the
Northeast Creek watershed. The flows of the Northeast Creek are then multiplied by the ratio to
estimate the flows for the Third Fork Creek. The flow duration curve for the Third Fork Creek
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
51
watershed is shown in Figure 5.1. Flow statistics as generated by the curves are presented in
Table 5.2.

Table 5.2: Flow Statistics for the Third Fork Creek.
High Flow
(< 10th percentile)
Transitional Flow
(Between 10th and 30th
percentile)
Typical Flow
(Between 30th and 90th
percentile)
Low Flow
(> 90th percentile)
47 –2616 cfs 5 – 47 cfs 3 – 5 cfs 1 –3 cfs

Figure 5.2. Flow Duration Curve for the Third Fork Creek. Flows from the Northeast Creek at
USGS 0209741955 were used to estimate flows for the Third Fork Creek.

The flow duration curve was used to determine the seasonality and flow regimes during which
the exceedances of the pollutants occurred. It was also used to determine maximum daily
pollutant load based on the flow duration and applicable standard.
5.2.3. Load Duration Curve
As discussed in Section 3.2.4, a load duration curve is developed by multiplying the flow values
along the flow duration curve by the pollutant concentrations and the appropriate conversion
factors. As seen in Figure 5.2, allowable and existing loads are plotted against the flow
0
1
10
100
1000
10000
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent flow exceeded
High
Flow Flow
Typical Flow Low
Flow
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
52
recurrence interval. The allowable load is based on the water quality numerical criteria, margin
of safety, and flow duration curve.

Following paragraphs discusses procedures to estimate endpoints for turbidity in the Third Fork
Creek in order to identify assimilative capacity of the creek in each flow conditions and to
identify the flow regime during which exceedances occur.

5.2.4.1. Turbidity Assimilative Capacity
Existing TSS loads to the Third Fork Creek was determined by multiplying the observed TSS
concentration by the flow observed on the date of observation and converting the result to daily
loading values. The assimilative capacities of the water bodies were determined by multiplying
the TSS concentration that is equivalent to a turbidity value of 50 NTU by the full range of
measured flow values. Figure 5.2 present the calculated load, (scatter plot) power line (dotted
line), and the TMDL target loading (solid line) for the creek.

Figure 5.2. TSS Load duration curve for Third Fork Creek at the coalition station, B3025000,
from April 2000 through September 2003.

0.01
0.1
1
10
100
1000
0.
0
%
10
.
0
%
20
.
0
%
30
.
0
%
40
.
0
%
50
.
0
%
60
.
0
%
70
.
0
%
80
.
0
%
90
.
0
%
10
0
.
0
%
Pecent Flow Exceeded
TS
S

L
o
a
d

(
t
o
n
s
/
d
a
y
)
Existing load Allowable load
Summer Existing Load Power (Existing load)
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
53
Except during low flow periods, the assimilative capacity of the Third Fork Creek exceeded the
targeted values (Figure 5.2). The result, therefore, suggests that non-point sources alone could
have increased turbidity level in the creek.

Furthermore, the power line that represented average existing TSS loads clearly explicated that
the TSS loads under natural background condition did not exceed the turbidity standard of 50
NTU (29 mg/L) in the Third Fork Creek (Figure 5.2). The power line passed underneath the
targeted line except during high flow period (<10% flow exceeded), which is indeed
unmanageable and hence is excluded in the TMDL estimation in this study.

5.3. Total Maximum Daily Loads (TMDL)
Sections 5.2 described the processes and rationale to identify the endpoints, assimilative
capacity, potential sources, and target loadings for each pollutant in the Third Fork Creek
watershed. These efforts formed the basis for the TMDL process. The key components required
by the TMDL guidelines to set the final TMDL allocation for the watershed is defined by the
equation 5.2.

TMDL = ∑WLAs + ∑LAs + MOS ---------------(5.2)
Where, WLA is waste load allocation (point source), LA is load allocation (non-point source),
and MOS is marginal of safety. Detail explanation of the equation is given in Section 3.3.

Following sections describe the key components required by the TMDL guidelines to set the
final TMDL allocation for the Watershed.
5.3.1. Margin of Safety (MOS)
The Margin of Safety was explicitly included in following TMDL analysis by setting the TMDL
target at 10 percent lower than the water quality target for turbidity.
5.3.2. Target Reduction
To determine the amount of turbidity reduction necessary to comply with the water quality
criteria, exceedances of the estimated standard (29 mg TSS/L) were identified within the 10th to
95th percentile flow recurrence range. A power curve through the data point violating the water
quality criterion was overlaid on the graph (Figure 5.3). The power curve equation is presented
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
54
in Equation 5.2. The correlation coefficient, R-Square, for the power curve is 0.71; thus
suggesting a reasonable fit of the curve.

Y = 0.3208 * X (-1.3974) R-Square = 0.71 ---------------------------(5.2)
Where, Y = Turbidity (mg/L) and X = Percent Flow Exceeded.
The criteria violations occurred through out the typical flow regime (Figure 5.3). As described
in Section 3.3, the loading estimates based on the power curve are presented in Appendix 4.
Approximately 53 percent reduction in turbidity is required in order to meet the water quality
standard and to account for the 10 percent of MOS. A summary of reductions required is
provided in Table 5.3.

Table 5.3. Reduction Required for TSS in the Third Fork Creek
Pollutants Target
with MOS
Existing Load Allowable Load Reduction
Required
TSS1 < 26 mg/L 1.58 tons/day 0.75 tons/day 53 %
1 TSS is used as a surrogate variable for turbidity

Figure 5.3. Load duration curve showing allowable and existing loads violation of the Third
Fork Creek.
0.1
1
10
10.00% 30.00% 50.00% 70.00% 90.00%
Percent Flow Exceeded
TS
S

L
o
a
d

(
t
o
n
s
/
d
a
y
)
Allowable Load Existing Load Violated
Power (Existing Load Violated)
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
55
5.3.3. TMDL Allocation
As identified by the above load duration curve method, significant amounts of TSS are required
to be reduced in the Third Fork Creek. In order to meet the TMDL objectives, the reduction
should be targeted towards non-point sources and MS4 areas.

5.3.3.1. Waste Load Allocation (WLA)
All TSS transported from the MS4 areas and waste load facility, Brenntag Southeast, were
assigned to the WLA components. The relative loading rates from the MS4 areas are discussed
in Section 3.3.3. A summary of the report and a description of method that was used to estimate
relative percent contribution of TSS from the urban and rural sources are presented in Appendix
11.3. The estimated relative percent contribution from the MS4 and rural areas (non-point
sources including non-MS4 area) are presented in Table 5.4.

Table 5.4. Relative TSS Contribution Rates for the Third Fork Creek.
Pollutants Load from MS4 areas (%) Load from other areas (%)
TSS 48 52

The assimilative capacity determined in Section 5.2.3 was split based on the relative
contributions presented in Table 5.4 to determine the allocation for the MS4 areas. The results of
these calculations are summarized in Table 5.5.

The WLA associated with construction and other land management activities, as discussed in
Section 5.1.2, is equivalent to the surface water quality standard for turbidity in that any
construction activity cannot cause or contribute to a violation of the water quality standard. As
discussed, these WLAs are and will be expressed as BMPs in the general or individual
constriction permits rather than as numeric effluent limits.

5.3.3.2. Load Allocation (LA)
All TSS loadings from non-point sources such as non-MS4 urban land, agriculture land, and
forested land were reported as LAs. The relative loading rates from these areas were determined
using the similar procedures as described in Section 3.3.2. (See also Appendix 11.3.) The
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
56
estimated relative percent contribution of TSS from the non-point sources is presented in Table
5.5.

able 5.5. Estimated TMDL and Load Allocation for TSS for the Third Fork Creek Watershed.
Pollutants Existing
Load
Construct-
ion
Activities
NPDES MS4

WLA1 LA MOS TMDL
TSS
(tons/day)
1.58 50 NTU 0.002 0.36 0.36 0.39 Explicit
10 %
0.75
1WLA = MS4 + NPDES (including construction activities)

5.3.3.3. Study Limitation
The available land cover for this study is outdated and fails to represent current land use
condition. Therefore, the estimation of WLA in Table 5.5 is not authoritative. The primary
focus of efforts to minimize future impairment should be on the percent reductions and control of
sources identified in the Source Assessment (see § 2).
5.3.4. Critical Condition and Seasonal Variation
According to the load duration curve (Figure 5.2), the greatest frequency of exceedances of
turbidity occurred during high-flow periods throughout the season. The result shows that wet
weather under high-flow period is the critical period for turbidity in the Third Fork Creek.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
57

6. Dan River Impairment

6.1. Source Assessment
As discussed in Section 1.1, population growth in Rockingham County and Stokes County are
alarming. Several developing activities such as land clearing and site preparation for residential
buildings, commercial areas, roads, and highways being conducted in the Dan River watershed.
These activities are the main sources of turbidity. Surface runoff carries sediments and solids
from these lands to the river and increases turbidity level. Transport of total suspended solids
(TSS) from a developed land is discussed in Section 2.1.

In addition, point sources such as waste water treatment plants (WWTP) and MS4 areas are also
responsible for TSS increment in a water body.
6.1.1. NPDES Wastewater Permits
There were about 26 facilities under the NPDES program that discharged wastewater to the Dan
River and its tributaries (Table 6.1). Of the 26 facilities, four facilities - Kobewireland Copper
Products, Madison WWTP, Danbury WWTP, and North Stokes High School - discharged
wastewater directly to the Dan River (Appendix 11.2). Except JPS Elastomerics Corp-Caro Plt,
the facilities were permitted to discharge up to 45 mg/L of TSS daily (Table 6.1). These
facilities are located in North Carolina. Statistics of the facilities in Virginia are not documented
in this study.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
58

Table 6.1. NPDES Wastewater Permits in the Dan River
Permit No. Facility Name
Permitted
Flow (MGD)
Daily Permitted Limits
TSS (mg/L)
NC0075027 Cains Way Mobile Home Park 0.0432 45
NC0078115 Greystone Subdivision WWTP 0.032 45
NC0083933 Rangecrest Road WWTP 0.06 45
NC0060461 Abington WWTP 0.385 45
NC0037311 Creekside Manor Rest Home 0.01 45
NC0028746 Briarwood Subdivision WWTP 0.05 45
NC0056791 Horizons Residential Care Ctr 0.015 45
NC0035173 Kobewireland Copper Products Incorporated 0.025 45
NC0044962 North Stokes High School 0.0115 45
NC0067091 Mikkola Downs WWTP 0.072 45
NC0029777 Stokes Correctional Center WWTP 0.0132 45
NC0059251 Quail Acres Mobile Home Park 0.018 45
NC0060542 Gold Hill Mobile Home Park 0.0176 45
NC0044750 Britthaven Of Madison 0.025 45
NC0037001 Bethany Elementary School 0.01 45
NC0003441 JPS Elastomerics Corp-Caro Plt 0.015 135
NC0044954 South Stokes High School 0.0173 45
NC0079049 R.H. Johnson Construction WWTP 0.06 45
NC0057720 Twin Lakes Mobile Home Park 0.04 45
NC0003492 R J Reynolds Tobacco Co - Brook Cove 0.02 45

Weekly Average
Permitted Limits
NC0021075 Madison WWTP 0.775 45
NC0082384 Danbury WWTP 0.1 45
NC0028011 Stoneville WWTP 0.25 45
NC0021873 Mayodan WWTP 4.5 45
NC0025526 Walnut Cove WWTP 0.5 45
NC0024406 Belews Creek Steam Station 0.01 45

6.1.2. NPDES General Permits
All construction activities in the Dan River watershed that disturb one or more acres of land are
subject to NC general permit NCG010000 and as such are required to not cause or contribute to
violations of Water Quality Standards. As stated in Permit NCG010000, page 2, “The
discharges allowed by this General Permit shall not cause or contribute to violations of Water
Quality Standards. Discharges allowed by this permit must meet applicable wetland standards as
outlined in 15A NCAC 2B .0230 and .0231 and water quality certification requirements as
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
59
outlined in 15A NCAC 2H .0500”. Monitoring requirements for these construction activities are
briefly explained in Section 3.1.2.
6.1.3. NPDES Stormwater MS4s
There was no municipality under the NPDES storm water program in the Dan River watershed.

6.2. Technical Approach
As discussed in Section 3.2, a load duration approach was adopted to identify source types,
specify assimilative capacity of a stream, and to estimate magnitude of load reduction required to
meet the water quality standard. In Section 3.2, essential components of developing a load
duration curve are discussed in detail. Following paragraphs explains its application for
developing turbidity TMDL for the Dan River.
6.2.1. Endpoint for Turbidity
As discussed in Section 3.2.1, total suspended solid (TSS) was selected as a surrogate measure
for the Dan River. In order to observe relationship between TSS and turbidity in the River, a
regression equation was developed using the observed data collected from February 1997
through March 2004 in the ambient station, N2300000. The equation is shown in Equation 6.1.
The coefficient of determination between the two parameters was 0.92, thereby suggesting a
significant relationship.

Y = 0.91 X + 1.105 R-Square = 0.92 ----------------------(6.1)

Where, Y = TSS in mg/l and X = turbidity in NTU.

Equation 6.1 suggests that the Dan River yielded approximately 1.105 mg/L of TSS under
natural condition (NTU = 0). The river increased TSS on an average by 0.91 mg/L for each
turbidity increase. Correspondingly, the river yielded 47 mg/L of TSS at the turbidity standard of
50 NTU.
6.2.2. Flow Duration Curve
Daily stream data collected from January 1939 through September 2003 at the USGS gage
station, 02071000 near Wentworth was used to develop flow duration curves. The flow duration
curve for the Dan River watershed is shown in Figure 6.1. Flow statistics as generated by the
curves are presented in Table 6.2.
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
60

Table 6.2: Flow Statistics for the Dan River.
High Flow
(< 10th percentile)
Transitional Flow
(Between 10th and 30th
percentile)
Typical Flow
(Between 30th and 90th
percentile)
Low Flow
(> 90th percentile)
2020 – 47800 cfs 601 – 2020 cfs 396 – 601 cfs 61 – 396 cfs

Figure 6.2. Flow Duration Curve for the Dan River at USGS 02071000 near Wentworth.

The flow duration curve was used to determine the seasonality and flow regimes during which
the exceedances of the pollutants occur. It was also used to determine maximum daily pollutant
load based on the flow duration and applicable standard.
6.2.3. Load Duration Curve
As discussed in Section 3.2.4, a load duration curve is developed by multiplying the flow values
along the flow duration curve by the pollutant concentrations and the appropriate conversion
factors. As seen in Figure 6.2, allowable and existing loads are plotted against the flow
1
10
100
1000
10000
100000
%0%0%0%0%0%0%0%0%00%
Percent Flow exceeded
Fl
o
w

(
c
f
s
)
High
Flow
Transitional
Flow
Typical Flow Low
Flow
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
61
recurrence interval. The allowable load is based on the water quality numerical criteria, margin
of safety, and flow duration curve.
Following paragraphs discusses procedures to estimate endpoints for turbidity in the Dan River
in order to identify assimilative capacity of the River in each flow conditions and to identify the
flow regime during which exceedances occur.

6.2.4.1. Turbidity Assimilative Capacity
Existing TSS loads to the Dan River was determined by multiplying the observed TSS
concentration by the flow observed on the date of observation and converting the result to daily
loading values. The assimilative capacities of the water bodies were determined by multiplying
the TSS concentration that is equivalent to a turbidity value of 50 NTU by the full range of
measured flow values. Figure 6.2 present the calculated load (scatter plot), power line (dotted
line), and the TMDL target loading (solid line) for the creek.

Figure 6.2. TSS Load duration curve for the Dan River at the ambient station, N2300000, from February
1997 through March 2004.

1.00
10.00
100.00
1000.00
10000.00
0%5%
10
%
15
%
20
%
25
%
30
%
35
%
40
%
45
%
50
%
55
%
60
%
65
%
70
%
75
%
80
%
85
%
90
%
95
%
10
0
%
Pecent Flow Exceeded
TS
S

(
t
o
n
s
/
d
a
y
)
Existing load Allowable load
Summer Existing Load Power (Existing load)
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
62
The assimilative capacity of the Dan River also exceeded the targeted values during all flow
periods except during low flow period (6.2). The result suggests that non-point sources alone
could have elevated turbidity level in the river.

Furthermore, the power line that represented average existing TSS loads clearly explicated that
the TSS loads under natural background condition did not exceed the turbidity standard of 50
NTU (47 mg/L) in the Dan River (Figure 5.2). The power line passed underneath the targeted
line except during high flow period (<10% flow exceeded), which is indeed unmanageable and
hence is excluded in the TMDL estimation in this study.

6.3. Total Maximum Daily Loads (TMDL)
Sections 6.2 described the processes and rationale to identify the endpoints, assimilative
capacity, potential sources, and target loadings for each pollutant in the Dan River watershed.
These efforts formed the basis for the TMDL process. The key components required by the
TMDL guidelines to set the final TMDL allocation for the watershed is defined by the equation
6.2.

TMDL = ∑WLAs + ∑LAs + MOS ---------------(6.2)
Where, WLA is waste load allocation (point source), LA is load allocation (non-point source),
and MOS is marginal of safety. Detail explanation of the equation is given in Section 3.3.

Following sections describe the key components required by the TMDL guidelines to set the
final TMDL allocation for the Watershed.
6.3.1. Margin of Safety (MOS)
The Margin of Safety was explicitly included in following TMDL analysis by setting the TMDL
target at 10 percent lower than the water quality target for turbidity.
6.3.2. Target Reduction
To determine the amount of turbidity reduction necessary to comply with the water quality
criteria, exceedances of the estimated standard (47 mg TSS/L) were identified within the 10th to
95th percentile flow recurrence range. A power curve through the data point violating the water
quality criterion was overlaid on the graph (Figure 6.3). The power curve equation is presented
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
63
in Equation 6.2. The correlation coefficient, R-Square, for the power curve is 0.96; thus
suggesting a reasonable fit of the curve.

Y = 42.578 * X (-1.5074) R-Square = 0.96 ---------------------------(6.2)
Where, Y = Turbidity (mg/L) and X = Percent Flow Exceeded.
The criteria violations occurred through out the typical flow regime (Figure 6.3). As described
in Section 3.3.2, the loading estimates based on the power curve are presented in Appendix 11.3.
Approximately 59 percent reduction in turbidity is required in order to meet the water quality
standard and to account for the 10 percent of MOS. A summary of reductions required is
provided in Table 6.3.

Table 6.3. Reduction Required for TSS in the Dan River
Pollutants Target
with MOS
Existing Load Allowable Load Reduction
Required
TSS1 < 42 mg/L 248.20 tons/day 101.74 tons/day 59 %
1 TSS is used as a surrogate variable for turbidity

10
100
1000
10.00% 30.00% 50.00% 70.00% 90.00%
Perecent Flow Exceeded
TS
S

l
o
a
d

(
t
o
n
s
/
d
a
y
)
Allowable Load Existing Exceeded Load
Power (Existing Exceeded Load)
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
64
Figure 6.3. Load duration curve showing allowable and existing loads of turbidity in the Dan
River.

6.3.3. TMDL Allocation
As identified by the above load duration curve method, significant amounts of TSS are required
to be reduced in the Dan River. In order to meet the TMDL objectives, the reduction should be
distributed over both point and non-point sources. A further analysis is, therefore, required to
determine the breakdown between point source and non-point source loadings.

6.3.3.1. Waste Load Allocation (WLA)
All contributions of TSS from the 26 facilities listed in Table 6.1 were reported as the WLA
components. The relative loading rates from the facilities are presented in Table 6.4.

The WLA associated with construction and other land management activities, as discussed in
Section 6.1.2, is equivalent to the surface water quality standard for turbidity in that any
construction activity cannot cause or contribute to a violation of the water quality standard. As
discussed, these WLAs are and will be expressed as BMPs in the general or individual
constriction permits rather than as numeric effluent limits.

6.3.3.2. Load Allocation (LA)
All TSS loadings from non-point sources such as urban, agriculture, and forested lands were
reported as LAs. The estimated relative percent contribution of TSS from the non-point sources
is presented in Table 6.4.

Table 6.4. Estimated TMDL and Load Allocation for TSS for the Dan River Watershed.
Pollutants Existing
Load
Construct-
ion
Activities
NPDES MS41

WLA2 LA MOS TMDL
TSS
(tons/day)
248.20 50 NTU 1.21 0 1.21 100.53 Explicit
10 %
101.74
1There are no MS4 areas in the Dan River watershed.
2WLA = MS4 + NPDES (including construction activities).

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
65
6.3.3.3. Study Limitation
The available land cover for this study is outdated and fails to represent current land use
condition. Therefore, the estimation of WLA in Table 6.4 is not authoritative. The primary
focus of efforts to minimize future impairment should focus on the percent reductions and
control of sources identified in the Source Assessment (see § 2).
6.3.3.4. Critical Condition and Seasonal Variation
The greatest frequency of exceedances of turbidity in the Dan River occurred during high-flow
periods throughout the season (Figure 6.2). The result shows that wet weather under high-flow
period is the critical period for turbidity in the Dan River.
7. Summary and Future Consideration
This report presents the development of Total Maximum Daily Loads (TMDLs) for the four
water bodies in North Carolina: Haw River, Deep River, Third Fork Creek, and Dan River. The
Haw River is located in the Cape Fear River Basin (CFRB) and is impaired due to fecal coliform
and turbidity. The Deep River and the Third Fork Creek are also located in the CFRB and are
impaired due to fecal coliform and turbidity respectively. The Dan River is located in the
Roanoke River Basin and is impaired due to turbidity.

Available water quality data were reviewed to determine the frequency of exceedances. A load
duration curve method was applied to determine the critical periods and the sources that lead to
exeedances of the standard. The necessary percent reduction to meet the TMDL requirement
was then calculated by taking a difference between the average of the power curve load estimates
and the average of the allowable load estimates. The summary of the results is as follows:

• About 61 percent reduction in turbidity and 77 percent reduction in fecal coliform are
required in order to meet the water quality standard in the Haw River. Storm runoff and
bank erosion are seen to be responsible for the exceedance of turbidity, whereas both
point and non-point sources are responsible for the exceedance of fecal coliform.

• About 75 percent reduction in fecal coliform is required in order to meet the water quality
standard in the Deep River. The combination of non-point and sporadic sources are the
major problem in the river.

• About 53 percent reduction in turbidity is required in order to meet the water quality
standard in the Third Fork Creek. Non-point sources are the major problem in the creek.
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
66

• About 59 percent reduction in turbidity is required in order to meet the water quality
standard in the Dan River. Non-point sources are the major problem in the River.

7.1 Stream Monitoring
Stream monitoring should continue on a monthly interval at the existing ambient monitoring
stations. The continued monitoring of TSS and fecal coliform concentrations will allow for the
evaluation of progress towards the goal of reaching water quality standards by comparing the
instream data to the TMDL target.

Furthermore, to comply with EPA guidance, North Carolina may adopt new bacteria standards
utilizing Escherichia coli (E. coli) or enterococci in the near future. Thus, in future, monitoring
efforts to measure compliance with this TMDL should include using E. coli or enterococci. Per
EPA recommendations (EPA, 2000b), if future monitoring for E. coli/enterococci indicates the
standard has not been exceeded, these monitoring data may be used to support delisting the water
body from the 303(d) list. If a continuing problem is identified using E. coli/enterococci, the
TMDL may be revised.

7.2 Implementation Plan
Reductions for fecal coliform should be sought through identification and repair of aging sewer
infrastructure as well as targeting other storm-driven sources. Enforcement of stormwater BMP
requirements for construction sites, additional education related to farming practices and other
land disturbing activities, and additional urban stormwater controls for sediment are potential
management options for improving turbidity levels.

For turbidity, much of the impairment is likely due to erosion from landuses during conversion
from rural to urban uses. While stormwater controls are typically required during development
activites, significant loadings can occur due to initial periods of land disturbance before controls
are in place or during high rainfall periods during which the controls are inadequate. Additional
turbidity impairment may be due to runoff from agricultural areas and from erosion of soils due
to increased imperviousness in urbanizing areas.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
67
The TMDL analysis was performed using the best data available to specify the fecal coliform
and total suspended solids reductions necessary to achieve water quality criteria. The intent of
meeting the criteria is to support the designated use classifications in the watershed. A detailed
implementation plan is not included in this TMDL. The involvement of local governments and
agencies will be needed in order to develop an implementation plan.

8. Public Participation
A draft of the TMDL was public noticed in local newspapers --The Herald Sun (Durham
County), The Times-News (Alamance County), The Stokes News (Stokes County), The
Reidsville Review (Rockingham County), and News and Record (Guilford County). The public
notice was announced through the papers on different dates starting from September 17, 2004
through September 20, 2004 (Appendix 11.5). The TMDL was also public noticed through DWQ
web site at http://h2o.enr.state.nc.us/tmdl/TMDL_list.htm#Draft_TMDLs.

A public comment period was through October 22, 2004. One written comment was received
through email and is included in Appendix 11.6. The comment was carefully considered and the
TMDL was revised accordingly.

9. Further Information
Technical questions regarding this TMDL should be directed to the following members of the
DWQ Modeling/TMDL Unit:
Narayan Rajbhandari, Environmental Modeler, ([e-mail]), and
Michelle Woolfolk, Supervisor ([e-mail]).

Further information concerning North Carolina’s TMDL program can be found on the Internet at
the Division of Water Quality website: http://h2o.enr.state.nc.us/tmdl/General_TMDLs.htm.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
68
10. References
Center for Watershed Protection. 1999. Microbes and Urban Watershed: Concentrations,
Sources, and Pathways. Watershed Protection Techniques 3(1): 554:565.

Cleland, B.R. 2002. TMDL Development from the “Bottom Up” – Part II: Using load duration
curve to connect the pieces. Proceeding from the WEF National TMDL Science and Policy 2002
Conference.

Division of Environmental Health (DEH). NCDENR. 2000. Report on the Proper Maintenance
of Septic Tank Systems in Accordance with Section 13.5 of HB 1160 (Clean Water Act of 1999).
http://www.deh.enr.state.nc.us/oww/Maintenance.PDF. March 15, 2000.

Hyer, Kenneth, Doughlas Moyer, and Trisha Baldwin. 2001. Bacteria Source Tracking to
Improve TMDL Development in Bacteria. U.S. Geological Survey, WRD, 1730 East Parham
Rd., Richmond, VA 23228. In va.water.usgs.gov/GLOBAL/posters/BST.pdf.

North Carolina Department of Agriculture and Consumer Services.
http://www.ncagr.com/stats/cntysumm/

North Carolina Department of Environment and Natural Resources. 2003. Surface Waters and
Wetlands Standards. Environmental Management Commission, Raleigh, NC.

North Carolina Department of Environment and Natural Resources. 2003. North Carolina Water
Quality Assessment and Impaired Waters List (2002 Integrated 305(b) and 303(d). Division of
Water Quality, Water Quality Section, Environmental Sciences Branch, 1617 Mail Service
Center, Raleigh, NC –27699-1617.

North Carolina Department of Environment and Natural Resources. 2004. Total Maximum
Daily Loads for Turbidity and Fecal Coliform for East Fork Deep River, North Carolina. Final
Report, March 2004.

North Carolina Department of Environment and Natural Resources.
http://www.deh.enr.state.nc.us/oww/

Stiles, T.C. 2002. Incorporating Hydrology in Determining TMDL Endpoints and Allocations.
Proceedings from the WEF National TMDL Science and Policy 2002 Conference.

U.S. Census Bureau. http://quickfacts.census.gov/qfd/states/

U.S. Environmental Protection Agency (USEPA). 1991. Guidance for Water Quality-Based
Decisions: The TMDL Process. Assessment and Watershed Protection Division, Washington,
DC.

U.S. Environmental Protection Agency (USEPA) 1998. Draft Final TMDL Federal Advisory
Committee Report. U.S. Environmental Protection Agency, Federal Advisory Committee
(FACA). Draft final TMDL Federal Advisory Committee Report. 4/28/98.
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
69
U.S. Environmental Protection Agency (USEPA) 1999. Protocol for Developing Sediment
TMDLs. First Edition. EPA 841-B-99-044. U.S. EPA, Office of Water, Washington D.C.

U.S. Environmental Protection Agency (USEPA) 2000a. Revisions to the Water Quality
Planning and Management Regulation and Revisions to the National Pollutant Discharge
Elimination System Program in Support of Revisions to the Water Quality Planning and
management Regulation; Final Rule. Fed. Reg. 65:43586-43670 (July 13, 2000).

U.S.Environmental Protection Agency (USEPA) 2000b. Implementation Guidance for Ambient
Water Quality Criteria for Bacteria – 1986. DRAFT. Office of Water. EPA-823-D-00-001.

U.S. Environmental Protection Agency (USEPA) 2001. Protocol for Developing Pathogen
TMDLs. First Edition. EPA 841-R-00-002. U.S. EPA, Office of Water, Washington D.C.

U. S. Geological Survey (USGS). 1999. Relation of Land Use to Streamflow and Water Quality
at Selected Sites in the City of Charlotte and Mecklenburg County, North Carolina, 1993-98.
Water Resources Investigations Report 99-4180, Raleigh, NC.

Wayland, R. November 22, 2002. Memorandum from Rober Wayland of the U. S.
Environmental Protection Agency to Water Division Directors. Subject: Establishing TMDL
Waste Load Allocation for stormwater sources and NPDES permit requirements based on those
allocations.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
70
11. APPENDICES

Appendix 11.1. Water Quality Parameters Used for TMDL Development

Appendix Table 11.1A. DWQ monitoring data of turbidity and flow in the Haw River at the
ambient station B1140000.
Sampling
Date
Flow
(cfs)
Turbidity
(NTU
Sampling
Date
Flow
(cfs)
Turbidity
(NTU
Sampling
Date
Flow
(cfs)
Turbidity
(NTU
1/30/1997 680 31 2/22/2000 492 15 11/19/2002 2110 36
2/26/1997 453 12 3/21/2000 2210 35 12/12/2002 3200 70
3/26/1997 989 13 4/19/2000 1540 33 1/6/2003 835 21
4/28/1997 4790 65 5/31/2000 214 11 2/12/2003 535 14
5/27/1997 712 22 6/26/2000 384 6.2 3/11/2003 824 20
6/25/1997 185 12 7/25/2000 699 75 4/2/2003 1210 26
7/17/1997 202 8.8 8/24/2000 99 5.6 5/20/2003 862 45
8/26/1997 654 47 9/20/2000 1310 60 6/23/2003 492 13
9/16/1997 124 13 10/18/2000 126 4.4 7/21/2003 352 17
10/22/1997 222 29 11/30/2000 182 7.4 8/18/2003 2500 85
11/24/1997 511 60 12/14/2000 145 6.7 9/11/2003 287 8.8
12/18/1997 238 2.2 1/31/2001 399 7.6
1/27/1998 2330 26 4/25/2001 295 3.7
2/14/1998 900 100 5/10/2001 136 3.7
3/24/1998 1210 39 6/19/2001 109 6.5
4/29/1998 584 13 7/26/2001 680 40
5/26/1998 349 18 8/30/2001 116 9.8
6/25/1998 165 4.2 9/26/2001 195 37
7/27/1998 137 3.5 10/23/2001 59 8.9
8/24/1998 95 5.9 11/28/2001 89 17
9/29/1998 94 2.4 12/19/2001 280 17
10/28/1998 69 2.1 1/30/2002 264 20
11/19/1998 97 2.2 2/6/2002 153 7.8
12/29/1998 259 14 3/13/2002 293 19
1/21/1999 520 45 4/3/2002 254 18
4/22/1999 202 5.3 5/8/2002 106 11
7/19/1999 139 6.9 6/5/2002 76 6.8
8/16/1999 221 2.9 7/1/2002 67 6
9/29/1999 3980 65 8/5/2002 54 10
11/18/1999 171 2.9 9/5/2002 209 18
12/22/1999 899 16 10/3/2002 90 5.4

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
71

Appendix 11.1 continued.

Appendix Table 11.1B. DWQ monitoring data of total Suspended solids (TSS) and flow in the
Haw River at the ambient station B1140000.
Sampling
Date
Flow
(cfs)
TSS
mg/L
TSS Load
(Tons/day)
Sampling
Date
Flow
(cfs)
TSS
mg/L
TSS Load
(Tons/day)


680 12 21.95

520 15 20.98


453 2 2.44

202 3 1.63


989 12 31.92 

139 6 2.24



4790 100 1288.51


221 23 13.67


712 42 80.44 

3980 78 835.08


185 8 3.98


171 1 0.46


202 10 5.43 

899 16 38.69


654 190 334.26 

492 10 13.23


124 9 3.00 

2210 54 321.02


222 8 4.78

1540 35 144.99


511 20 27.49 

214 9 5.18



238 1 0.64 

384 7 7.23



2330 14 87.75 


126 2 0.68



900 86 208.21

399 6 6.44



1210 11 35.80

295 8 6.35



584 1 1.57 

680 60 109.75



349 12 11.27 

59 5 0.79



165 5 2.22

264 8 5.68



137 7 2.58

254 9 6.15



95 5 1.28 

67 6 1.08



94 4 1.01 

90 3 0.73




69 2 0.37

835 8 17.97



97 5 1.30

1210 13 42.31



259 7 4.88 

352 8 7.58

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
72
Appendix 11.1 continued.
Appendix Table 11.1C. DWQ monitoring data of fecal coliform and flow in the Haw River at
the ambient station B1140000.
Sampling
Date Flow
Fecal
Coliform
(#/100mL)
Fecal
Coliform
(#/day)
Sampling
Date Flow
Fecal
Coliform
(#/100mL)
Fecal
Coliform
(#/day)
Sampling
Date Flow
Fecal
Coliform
(#/100mL)
Fecal
Coliform
(#/day)
1/30/1997 680 100 1.66E+12 2/22/2000 492 140 1.69E+12 6/18/2002 60 50 7.34E+10
2/26/1997 453 18 1.99E+11 3/21/2000 2210 3100 1.68E+14 6/25/2002 49 25 3.00E+10
3/26/1997 989 230 5.57E+12 4/19/2000 1540 760 2.86E+13 6/27/2002 59 1000 1.44E+12
4/28/1997 4790 910 1.07E+14 5/31/2000 214 260 1.36E+12 7/1/2002 67 1 1.64E+09
5/27/1997 712 400 6.97E+12 6/26/2000 384 6400 6.01E+13 7/2/2002 60 240 3.52E+11
6/25/1997 185 300 1.36E+12 7/25/2000 699 6400 1.09E+14 7/9/2002 49 31 3.72E+10
7/17/1997 202 2400 1.19E+13 8/24/2000 99 45 1.09E+11 8/5/2002 54 96 1.27E+11
8/26/1997 654 390 6.24E+12 9/20/2000 1310 3500 1.12E+14 9/5/2002 209 70 3.58E+11
9/16/1997 124 240 7.28E+11 10/18/2000 126 740 2.28E+12 10/3/2002 90 58 1.28E+11
10/22/1997 222 210 1.14E+12 11/30/2000 182 76 3.38E+11 11/19/2002 2110 230 1.19E+13
11/24/1997 511 460 5.75E+12 12/14/2000 145 64 2.27E+11 12/12/2002 3200 3800 2.98E+14
12/18/1997 238 300 1.75E+12 1/31/2001 399 60 5.86E+11 1/6/2003 835 59 1.21E+12
1/27/1998 2330 200 1.14E+13 4/25/2001 295 470 3.39E+12 2/12/2003 535 39 5.10E+11
2/14/1998 900 2000 4.40E+13 5/10/2001 136 18 5.99E+10 3/11/2003 824 46 9.27E+11
3/24/1998 1210 90 2.66E+12 6/19/2001 109 40 1.07E+11 4/2/2003 1210 300 8.88E+12
4/29/1998 584 140 2.00E+12 8/30/2001 116 34 9.65E+10 5/20/2003 862 970 2.05E+13
5/26/1998 349 790 6.75E+12 9/26/2001 195 350 1.67E+12 6/23/2003 492 50 6.02E+11
6/25/1998 165 27 1.09E+11 10/23/2001 59 260 3.75E+11 7/21/2003 352 110 9.47E+11
7/27/1998 137 45 1.51E+11 11/28/2001 89 41 8.93E+10 8/18/2003 2500 8200 5.02E+14
8/24/1998 95 140 3.25E+11 1/30/2002 264 29 1.87E+11 9/11/2003 287 120 8.43E+11
9/29/1998 94 560 1.29E+12 2/6/2002 153 56 2.10E+11
10/28/1998 69 91 1.54E+11 3/13/2002 293 60 4.30E+11
11/19/1998 97 10 2.37E+10 4/3/2002 254 360 2.24E+12
12/29/1998 259 640 4.06E+12 5/8/2002 106 73 1.89E+11
1/21/1999 520 64 8.14E+11 5/21/2002 92 51 1.15E+11
4/22/1999 202 36 1.78E+11 5/30/2002 75 530 9.73E+11
7/19/1999 139 36 1.22E+11 6/4/2002 86 63 1.33E+11
8/16/1999 221 180 9.73E+11 6/5/2002 76 53 9.85E+10
9/29/1999 3980 3600 3.51E+14 6/11/2002 66 44 7.10E+10
11/18/1999 171 600 2.51E+12 6/13/2002 67 52 8.52E+10

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
73
Appendix 11.1 continued.
Appendix Table 11.1D. DWQ monitoring data of fecal coliform and flow
in the Deep River at the ambient station B4615000.
Sampling
Date Flow
Fecal
Coliform
(#/100mL)
Fecal
Coliform
(#/day)
Sampling
Date Flow
Fecal
Coliform
(#/100mL)
Fecal
Coliform
(#/day)
1/23/1997 103 45 1.13E+11 2/23/2000 99 320 7.75E+11
2/25/1997 102 10 2.50E+10 3/30/2000 66 640 1.03E+12
3/25/1997 102 62 1.55E+11 4/26/2000 71 120 2.08E+11
4/29/1997 4220 3500 3.61E+14 5/30/2000 30 81 5.95E+10
5/5/1997 222 640 3.48E+12 6/28/2000 93 73 1.66E+11
5/22/1997 45 72 7.93E+10 7/27/2000 53 320 4.15E+11
6/2/1997 62 200 3.03E+11 8/16/2000 29 91 6.46E+10
6/26/1997 25 27 1.65E+10 9/26/2000 392 1800 1.73E+13
7/28/1997 25 10 6.12E+09 10/30/2000 30 18 1.32E+10
8/28/1997 16 140 5.48E+10 11/29/2000 36 63 5.55E+10
9/29/1997 31 91 6.90E+10 12/21/2000 34 960 7.99E+11
11/19/1997 28 45 3.08E+10 1/16/2001 26 120 7.63E+10
12/17/1997 27 14 9.25E+09 4/3/2001 288 1000 7.05E+12
1/26/1998 186 73 3.32E+11 5/22/2001 42 160 1.64E+11
2/23/1998 494 100 1.21E+12 6/25/2001 47 50 5.75E+10
3/16/1998 79 36 6.96E+10 7/17/2001 24 11 6.46E+09
4/22/1998 206 82 4.13E+11 9/17/2001 21 33 1.70E+10
5/20/1998 152 110 4.09E+11 10/4/2001 17 28 1.16E+10
6/17/1998 62 310 4.70E+11 1/17/2002 21 15 7.71E+09
7/16/1998 21 27 1.39E+10 2/12/2002 47 55 6.32E+10
8/18/1998 49 420 5.04E+11 3/21/2002 105 31 7.96E+10
9/9/1998 102 980 2.45E+12 6/25/2002 16 26 1.02E+10
10/14/1998 20 110 5.38E+10 7/18/2002 17 40 1.66E+10
11/5/1998 20 20 9.79E+09 8/13/2002 14 10 3.43E+09
12/15/1998 53 260 3.37E+11 9/12/2002 16 46 1.80E+10
1/19/1999 260 54 3.44E+11 10/14/2002 722 2900 5.12E+13
3/17/1999 77 45 8.48E+10 11/20/2002 149 5200 1.90E+13
5/26/1999 24 18 1.06E+10 12/18/2002 107 150 3.93E+11
6/15/1999 19 24 1.12E+10 1/7/2003 117 770 2.20E+12
7/27/1999 32 82 6.42E+10 2/19/2003 248 510 3.09E+12
8/31/1999 42 330 3.39E+11 3/4/2003 241 260 1.53E+12
9/30/1999 939 6000 1.38E+14 4/1/2003 252 14000 8.63E+13
10/28/1999 32 80 6.26E+10 5/20/2003 153 180 6.74E+11
11/23/1999 34 81 6.74E+10 6/10/2003 374 1200 1.10E+13
12/28/1999 43 82 8.63E+10 7/15/2003 179 800 3.50E+12
8/12/2003 475 4100 4.76E+13
9/22/2003 101 200 4.94E+11

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
74
Appendix 11.1 continued.
Appendix Table 11.1E. UCFRBA monitoring data of TSS, turbidity, and flow in the Third Fork
Creek at the ambient station B30325000.
Sampling
Date
Flow (cfs)
(cfs)
TSS
(mg/L)
Turbidity
(NTU)
TSS Load
(ton/day)
Sampling
Date
Flow (cfs)
(cfs)
TSS
(mg/L)
Turbidity
(NTU)
TSS Load
(ton/day)
4/26/2000 14.84 23.00 21.00 0.92 8/7/2003 13.60 29.00
5/4/2000 10.93 39.00 40.00 1.15 9/25/2003 14.40 20.00
6/5/2000 7.50 98.00 89.00 1.98
7/6/2000 7.81 27.00 16.00 0.57
8/2/2000 83.57 48.00 110.00 10.79
9/6/2000 9.37 19.00 38.00 0.48
10/10/2000 4.06 6.00 3.60 0.07
11/20/2000 7.65 11.00 16.00 0.23
12/5/2000 4.06 3.50 23.00 0.04
1/17/2001 17.18 3.00 14.70 0.14
2/15/2001 28.12 5.50 20.00 0.42
3/14/2001 10.15 7.00 15.00 0.19
4/5/2001 12.50 21.00 90.00 0.71
5/10/2001 3.83 12.50 17.00 0.13
6/14/2001 23.43 84.20 75.00 5.31
7/2/2001 3.83 16.60 33.00 0.17
8/1/2001 2.34 16.00 21.00 0.10
9/3/2001 8.59 17.50 12.00 0.40
10/2/2001 4.84 11.50 50.00 0.15
11/1/2001 5.70 18.50 6.80 0.28
12/13/2001 2.42 24.00 39.00 0.16
1/2/2002 3.83 6.00 3.50 0.06
2/5/2002 8.59 2.70 14.00 0.06
3/5/2002 5.62 10.30 20.00 0.16
4/2/2002 15.62 37.00 45.00 1.55
5/2/2002 5.62 11.00 11.00 0.17
6/3/2002 2.97 25.00 16.00 0.20
7/1/2002 4.76 31.00 33.00 0.40
8/2/2002 3.75 7.80 14.00 0.08
9/2/2002 32.80 18.00 29.00 1.59
10/2/2002 5.15 3.20 8.10 0.04
11/5/2002 11.72 3.80 13.00 0.12
12/10/2002 23.43 7.90 16.00 0.50
1/6/2003 14.06 10.00 20.00 0.38
2/6/2003 13.28 9.60 22.00 0.34
3/10/2003 12.50 11.10 24.00 0.37
4/7/2003 97.63 168.00 130.00 44.12
5/7/2003 9.37 22.00 37.00 0.55
6/3/2003 12.50 14.00 28.00 0.47
7/9/2003 6.40 10.50 20.00 0.18
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
75
Appendix 11.1 continued

Appendix Table 11.1F. DWQ monitoring data of TSS, turbidity, and flow in the Dan River at
the ambient station N2300000.
Sampling
Date
Flow
(cfs)
TSS
(mg/L)
Turbidity
(NTU)
TSS Load
(tons/day)
Sampling
Date
Flow
(cfs)
TSS
(mg/L)
Turbidity
(NTU)
TSS Load
(tons/day)
2/20/1997 1440.00 7.00 11.00 27.12 1/25/1999 3210.00 110.00 120.00 949.84
3/20/1997 4640.00 64.00 70.00 798.82 4/20/1999 591.00 3.00 5.60 4.77
4/24/1997 3280.00 35.00 26.00 308.81 6/9/1999 418.00 8.00 5.60 9.00
5/28/1997 1210.00 8.00 7.90 26.04 7/28/1999 660.00 1.00 6.20 1.78
6/25/1997 939.00 15.00 10.00 37.89 8/25/1999 591.00 51.00 60.00 81.08
7/24/1997 1250.00 34.00 21.00 114.33 9/27/1999 279.00 26.00 28.00 19.51
8/21/1997 1090.00 43.50 26.00 127.55 10/21/1999 762.00 1.00 7.70 2.05
9/15/1997 846.00 53.00 26.00 120.61 11/8/1999 476.00 5.00 2.30 6.40
10/27/1997 736.00 14.00 11.00 27.72 2/29/2000 775.00 4.00 3.90 8.34
11/12/1997 595.00 1.00 2.60 1.60 3/22/2000 2610.00 52.00 50.00 365.09
1/6/1998 758.00 2.00 4.20 4.08 4/24/2000 845.00 13.00 9.30 29.55
1/22/1998 978.00 5.00 7.10 13.15 5/16/2000 516.00 8.00 4.40 11.10
2/19/1998 2580.00 53.00 50.00 367.83 6/15/2000 509.00 11.00 9.00 15.06
3/10/1998 4000.00 80.00 29.65 860.80 7/26/2000 354.00 4.00 5.60 3.81
4/28/1998 1310.00 11.00 9.30 38.76 8/29/2000 862.00 56.00 70.00 129.85
5/28/1998 1450.00 160.00 200.00 624.08 9/27/2000 1190.00 73.00 80.00 233.68
6/23/1998 750.00 10.00 9.10 20.18 12/11/2000 347.00 5.00 2.80 4.67
7/22/1998 500.00 17.00 14.00 22.87 6/21/2001 328.00 4.00 5.50 3.53
8/26/1998 451.00 9.00 13.00 10.92 9/13/2001 237.00 9.00 9.50 5.74
9/24/1998 414.00 4.00 5.30 4.45 12/18/2001 702 33.00 45.00 62.32
10/22/1998 329.00 4.00 4.50 3.54 3/4/2002 808 10.00 13.00 21.74
11/24/1998 383.00 5.00 4.30 5.15 6/4/2002 240 12.00 15.00 7.75
12/14/1998 2220.00 160.00 120.00 955.49 9/17/2002 328 17.00 37.00 15.00
12/17/2002 1060 15.00 20.00 42.77
3/26/2003 1780 38.00 55.00 181.95
6/3/2003 1380 14.00 15.00 51.97
9/30/2003 1080 14.00 15.00 40.67

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
76
Appendix 11.2. NPDES Permits
Watersheds Permit No. Facility Name Facility Types NC County Receiving Water Body Flow Daily TSS
Daily Fecal
Coliform
(MGD)(mg/L) (#/100mL)
Haw River NC0046809
Pentecostal Holiness
Church
Discharging 100% Domestic <
1MGD Guilford Benaja Creek 0.02 45 400
Haw River NC0066966
Quarterstone Farm
WWTP
Discharging 100% Domestic <
1MGD Guilford Buffalo Creek 0.16 45 400
Haw River NC0001384 Williamsburg plant
Industrial Process &
Commercial Wastewater
Discharge Caswell Buttermilk Creek 0.025 45 400
Haw River NC0045144
Western Alamance
High School
Discharging 100% Domestic <
1MGD Alamance HAW RIVER 0.01 45 400
Haw River NC0031607
Western Alamance
Middle School
Discharging 100% Domestic <
1MGD Alamance HAW RIVER 0.015 45 400
Haw River NC0046043
Oak Ridge Military
Academy
Discharging 100% Domestic <
1MGD Guilford HAW RIVER 0.04 45 400
Haw River NC0045161
Altamahaw/Ossipee
Elementary School
Discharging 100% Domestic <
1MGD Alamance HAW RIVER 0.012 45 400
Haw River NC0046019 The Summit WWTP
Discharging 100% Domestic <
1MGD Rockingham HAW RIVER 0.015 45 400
Haw River NC0066010
Williamsburg
Elementary School
Discharging 100% Domestic <
1MGD Rockingham HAW RIVER 0.004 45 400
Haw River NC0003913
Altamahaw Division
plant
Industrial Process &
Commercial Wastewater
Discharge Alamance HAW RIVER 0.15 108 400
Haw River NC0065412
Pleasant Ridge
WWTP
Discharging 100% Domestic <
1MGD Rockingham Little Troublesome Creek 0.0235 45 400
Haw River NC0060259
Willow Oak Mobile
Home Park
Discharging 100% Domestic <
1MGD Rockingham Little Troublesome Creek 0.0175 135 400
Haw River NC0084778
Harvin Reaction
Technology
Groundwater Remediation
Discharge Guilford North Buffalo Creek 0.11 45 400
Haw River NC0029726 Center WWTP
Discharging 100% Domestic <
1MGD Guilford North Buffalo Creek 0.025 45 400
Haw River NC0038156
Northeast Middle &
Senior High WWTP
Discharging 100% Domestic <
1MGD Guilford Reedy Fork 0.032 45 400
Haw River NC0022691
Autumn Forest
Manuf. Home
Community
Discharging 100% Domestic <
1MGD Guilford Reedy Fork 0.082 45 400
Haw River NC0001210
Monarch Hosiery
Mills Incorporated
Industrial Process &
Commercial Wastewater
Discharge Alamance Reedy Fork 0.05 81.5 NA
Haw River NC0038172 School WWTP
Discharging 100% Domestic <
1MGD Guilford South Buffalo Creek 0.0113 45 400
Haw River NC0055271 Park
Discharging 100% Domestic <
1MGD Alamance Travis Creek 0.006 45 400
Haw River NC0073571
Countryside Manor
WWTP
Discharging 100% Domestic <
1MGD Guilford Troublesome Creek 0.015 45 400
Deep River NC0038091
Southern Elementary
School
Discharging 100% Domestic <
1MGD Guilford Hickory Creek 0.0075 45 400
Deep River NC0038229
Southern Guilford
High School
Discharging 100% Domestic <
1MGD Guilford Hickory Creek 0.012 45 400
Deep River NC0055255
Crown Mobile Home
Park
Discharging 100% Domestic <
1MGD Guilford Hickory Creek 0.042 45 400
Deep River NC0041483
Plaza Mobile Home
Park
Discharging 100% Domestic <
1MGD Guilford Hickory Creek 0.003 45 400
Third Fork
Creek NC0086827
Brenntag Southeast,
Inc.
Groundwater Remediation
Discharge Durham Third Fork Creek 0.0144 30 NA
Dan River NC0075027
Cains Way Mobile
Home Park
Discharging 100% Domestic <
1MGD Forsyth Ader Creek 0.0432 45 400
Dan River NC0078115
Greystone
Subdivision WWTP
Discharging 100% Domestic <
1MGD Forsyth Belews Creek 0.032 45 400
Dan River NC0083933
Rangecrest Road
WWTP
Discharging 100% Domestic <
1MGD Forsyth Belews Creek 0.06 45 400
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
77
Appendix 11.2 continued
Dan River NC0060461 Abington WWTP
Discharging 100% Domestic <
1MGD Forsyth Belews Creek 0.385 45 400
Dan River NC0037311
Creekside Manor
Rest Home
Discharging 100% Domestic <
1MGD Forsyth Belews Creek 0.01 45 400
Dan River NC0028746
Briarwood
Subdivision WWTP
Discharging 100% Domestic <
1MGD Stokes Brushy Fork Creek 0.05 45 400
Dan River NC0056791
Horizons Residential
Care Ctr
Discharging 100% Domestic <
1MGD Forsyth Buffalo Creek 0.015 45 400
Dan River NC0035173
Kobewireland
Copper Products
Incorporated
Industrial Process &
Commercial Wastewater
Discharge Stokes DAN RIVER 0.025 45 400
Dan River NC0044962
North Stokes High
School
Discharging 100% Domestic <
1MGD Stokes DAN RIVER 0.0115 45 400
Dan River NC0067091
Mikkola Downs
WWTP
Discharging 100% Domestic <
1MGD Forsyth East Belews Creek 0.072 45 400
Dan River NC0029777
Stokes Correctional
Center WWTP
Discharging 100% Domestic <
1MGD Stokes Flat Shoals Creek 0.0132 45 400
Dan River NC0059251
Quail Acres Mobile
Home Park
Discharging 100% Domestic <
1MGD Rockingham Hogans Creek 0.018 45 400
Dan River NC0060542
Gold Hill Mobile
Home Park
Discharging 100% Domestic <
1MGD Rockingham Hogans Creek 0.0176 45 400
Dan River NC0044750
Britthaven Of
Madison
Industrial Process &
Commercial Wastewater
Discharge Rockingham Hogans Creek 0.025 45 400
Dan River NC0037001
Bethany Elementary
School
Discharging 100% Domestic <
1MGD Rockingham Huffines Mill Creek 0.01 45 400
Dan River NC0003441
JPS Elastomerics
Corp-Caro Plt
Industrial Process &
Commercial Wastewater
Discharge Stokes Little Dan River 0.015 135 NA
Dan River NC0044954
South Stokes High
School
Discharging 100% Domestic <
1MGD Stokes Little Neatman Creek 0.0173 45 400
Dan River NC0079049
R.H. Johnson
Construction WWTP
Discharging 100% Domestic <
1MGD Forsyth Rough Fork 0.06 45 400
Dan River NC0057720
Twin Lakes Mobile
Home Park
Discharging 100% Domestic <
1MGD Stokes Timmons Creek 0.04 45 400
Dan River NC0003492
R J Reynolds
Tobacco Co - Brook
Cove
Industrial Process &
Commercial Wastewater
Discharge Stokes
Voss Creek (Sandy
Branch) 0.02 45 400

Weekly Average
Permitted Limits
Haw River NC0023868 Eastside WWTP
Municipal Wastewater
Discharge, Large Alamance HAW RIVER 12 45 400 GM
Haw River NC0024881 Reidsville WWTP
Municipal Wastewater
Discharge, Large Rockingham HAW RIVER 7.5 45 400 GM
Haw River NC0024325
North Buffalo Creek
WWTP
Municipal Wastewater
Discharge, Large Guilford North Buffalo Creek 16 45 400 GM
Haw River NC0047384 T.Z. Osborne WWTP
Municipal Wastewater
Discharge, Large Guilford South Buffalo Creek 40 45 400 GM
Deep River NC0024210 East Side WWTP
Municipal Wastewater
Discharge, Large Guilford Richland Creek 26 45 400 GM
Dan River NC0021075 Madison WWTP
Municipal Wastewater
Discharge, < 1MGD Rockingham DAN RIVER 0.775 45 400 GM
Dan River NC0082384 Danbury WWTP
Municipal Wastewater
Discharge, < 1MGD Stokes DAN RIVER 0.1 45 400 GM
Dan River NC0028011 Stoneville WWTP
Municipal Wastewater
Discharge, < 1MGD Rockingham Mayo River 0.25 45 400 GM
Dan River NC0021873 Mayodan WWTP
Municipal Wastewater
Discharge, Large Rockingham Mayo River 4.5 45 400 GM
Dan River NC0025526 Walnut Cove WWTP
Municipal Wastewater
Discharge, < 1MGD Stokes Town Fork Creek 0.5 45 400 GM
Dan River NC0024406
Belews Creek Steam
Station
Industrial Process &
Commercial Wastewater
Discharge Stokes West Belews Creek 0.01 45 400 GM
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
78
Appendix 11.3. Load Reduction Estimations

Appendix Table 11.3A. Estimation of Load Reduction Required
in turbidity (tons TSS / day) for the Haw River.
Existing Load Allowable Load
Percent Flow
Exceeded
TSS
Load
Percent Flow
Exceeded
TSS
Load
15.00% 208.206 10.00% 104.5388
19.30% 80.44176 15.00% 74.90574
20.20% 109.752 20.00% 58.03137
21.20% 334.2594 25.00% 47.57749

Average 183.1648 71.26335
Load Reduction = 61%
Note: Power curve estimation is not used for the data point
violating the water quality criteria.

Appendix Table 11.3B. Estimation of Load Reduction Required
in fecal coliform (# / day) for the Haw River.

%flow
Exceeded
Allaowable
Load
(# / day)
Est. Voilated
Loads
# / day)
10.000% 1.11858E+13
15.000% 8.01502E+12
20.000% 6.20944E+12
25.000% 5.09086E+12
30.000% 4.29817E+12 1.44619E+
35.000% 3.74328E+12
40.000% 3.3117E+12
45.000% 2.92416E+12
50.000% 2.59828E+12
55.000% 2.30762E+12
60.000% 2.03458E+12
65.000% 1.79677E+12
70.000% 1.57658E+12 3.59
75.000% 1.39162E+12
80.000% 1.22427E+12
85.000% 1.05693E+12
90.000% 8.80772E+11

6.69387E+11
Average 3.35085E+12
Load Reduction = 77%

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
79
Appendix 11.3 continued.
Appendix Table 11.3C. Estimation of Load Reduction Required
in fecal coliform (# / day) for the Deep River.
% Flow
Exceeded
Fecal
Load
(#/day)
Est. Exceeded
Load
(#/day)
10.00% 2.14908E+12 1.82991E+13
15.00% 1.56777E+12 8.26123E+12
20.00% 1.21547E+12 4.69883E+12
25.00% 9.95272E+11 3.03327E+12
30.00% 8.27926E+11 2.12131E+12
35.00% 7.04618E+11 1.56782E+12
40.00% 6.07733E+11 1.20656E+12
45.00% 5.28463E+11 9.57677E+11
50.00% 4.58001E+11 7.78879E+11
55.00% 3.96347E+11 6.46075E+11
60.00% 3.34693E+11 5.44708E+11
65.00% 2.92416E+11 4.65567E+11
70.00% 2.55424E+11 4.02582E+11
75.00% 2.29001E+11 3.51629E+11
80.00% 1.94E+11 3.0982E+11
85.00% 1.67E+11 2.75086E+11
90.00% 1.50E+11 2.45911E+11

1.15E+11 2.21168E+11
Average 6.21531E+11 2.46596E+12
Load Reduction = 75%

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
80
Appendix 11.3 continued.

Appendix Table 11.3D. Estimation of Load Reduction Required
in Turbidity (# TSS / day) for the Third Fork Creek.
% Flow
Exceeded
TSS
Load
(ton/day)
Est. Load
Violated
(ton/day)
10.00% 3.290173 8.010034
15.00% 1.864432 4.54532
20.00% 1.316069 3.04071
25.00% 1.041888 2.226143
30.00% 0.822543 1.725461
35.00% 0.712871 1.391085
40.00% 0.603198 1.154292
45.00% 0.542879 0.979118
50.00% 0.493526 0.845072
55.00% 0.444173 0.739693
60.00% 0.405788 0.655007
65.00% 0.367403 0.585692
70.00% 0.329017 0.528073
75.00% 0.301599 0.479539
80.00% 0.274181 0.438184
85.00% 0.246763 0.402591
90.00% 0.219345 0.371686
95.00% 0.18096 0.344638
Average 0.747601 1.581241
Load Reduction = 53%

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
81
Appendix 11.3 continued.

Appendix Table 11.3E. Estimation of Load Reduction Required
in Turbidity (# TSS / day) for the Dan River.
% Flow
Exceeded
TSS
Load
(tons/day)
Est. Load
Violated
(ton/day)
10.00% 229.8497 1369.863
15.00% 185.4728 743.4249
20.00% 160.4397 481.8418
25.00% 143.3716 344.209
30.00% 129.7172 261.4956
35.00% 118.3385 207.2759
40.00% 108.439 169.4852
45.00% 100.7015 141.9138
50.00% 92.96398 121.0737
55.00% 86.13676 104.8707
60.00% 79.6509 91.97967
65.00% 74.18912 81.52512
70.00% 68.38599 72.90818
75.00% 63.038 65.70671
80.00% 57.57622 59.6155
85.00% 52.00066 54.40903
90.00% 45.05965 49.91739
95.00% 35.95669 46.01045
Average 101.7382 248.1959
Load Reduction = 59%

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
82
Appendix 11.4. Estimates of Relative Loadings for Point and Non-point
Sources

Appendix Table 11.4A. Estimates of TSS and Fecal Coliform Runoff Loading Rates
for Urban and Rural Lands (USGS, 1999).
Land Use Type
TSS Conc
(tons/Sq. mi)
FC Conc.
mg/L

Mixed forest/pasture/low density residential 2400 15
Mixed forest/pasture/medium & low density residential 2100 20
Mixed forest/pasture/medium & low density residential 564 24.5

Rural Average 1688 20

Industrial 122 27.5
Industrial 300 14.6
Medium-density residential 225 29
Medium-density residential 77 26.5
High-density residential 1000 15
Developing 4700 13

Urban Average 1071 21

Appendix Table 11.4B. Relative TSS Loading from Urban and Rural Areas.

Watershed Land Use Land %

Relative
TSS
Rate
tons/sq mi/yr
Normalized
TSS
Load Rates
tons/sq mi/yr
TSS
Loading
Ratio
Haw River Rural 82.77 1688 1397.1576 88.33%
MS4 17.23 1071 184.5333 11.67%

Deep River Rural 73.41 1688 NA NA
MS4 26.59 1071 NA NA

Third Fork Creek Rural 40.84 1688 689.3792 52.11%
MS4 59.16 1071 633.6036 47.89%

Dan River Rural 100 1688 1688 100.00%
MS4 0 0 0 0
Note: TSS data estimated in Appendix Table 4A was utilized to estimate average sediment loading in
stormwater runoff. The relative percent contributions of TSS were multiplied by the land use distribution
and normalized to estimate the relative loading percentage for urban (MS4) and rural (non-MS4) areas.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
83
Appendix 11.4 continued.

Appendix Table 11.4C. Relative Fecal Coliform Concentration from Urban and Rural areas

Watershed Land Use Land %
Relative
Fecal
Rate
(mg/L)
Normalized
Fecal Coliform
Conc. Rates
(mg/100mL)
Fecal Coliform
Conc. Ratio
Haw River Rural 82.77 20 16.554 82.06%
MS4 17.23 21 3.6183 17.94%

Deep River Rural 73.41 20 14.682 72.45%
MS4 26.59 21 5.5839 27.55%

Third Fork Creek Rural 40.84 20 NA NA
MS4 59.16 21 NA NA

Dan River Rural 100 20 NA NA
MS4 0 0 NA NA
Note: Fecal coliform data estimated in Appendix Table 4A was utilized to estimate average fecal
coliform concentrations in stormwater runoff. The relative percent contributions of fecal coliform were
multiplied by the land use distribution and normalized to estimate the relative loading ratio for urban
(MS4) and rural (non-MS4) areas.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
84
Appendix 11.5. Public Notice

The Herald Sun

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
85
Appendix 11.5 continued.

The Times-News

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
86

Appendix 11.5 continued.

The Stokes News

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
87

Appendix 11.5 continued.
The Reidsville Review

Appendix 11.5 continued.
Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
88

News and Record

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
89

Appendix 11.6. Public Comments and DWQ Response

Followings are the comments received from Mr. Steve Shoaf, City of Burlington, NC and the
DWQ’ s responses to the comments. The comments are in plain text and the responses are in
italics.

Comment 1. Page i: The stream segment identified for the Haw River (19.2 miles) is very
discrete. How was this segment determined when it is possible that the contributing pollutants
are coming from an upstream section?

The impaired segment in the Haw River from NC 87 to NC 40 was explicitly defined in the NC
Water Quality Assessment and Impaired Waters List (2002 Integrated 305 (b) and 303(d)
Report). The actual hydraulic length of the segment was approximately 13 miles. The 19.2 miles
as estimated in the 303(d) list was incorrect. The actual distance is corrected in the final TMDL
report.

Comment 2. Page 3: The first bullet item identifies the segment of the Haw River that is
impaired, but states that the segment is 13 miles. Is the distance correct?

The distance is correct.

Comment 3. Page 6: The paragraph below the definitions states that “Once EPA approves a
TMDL, then the water body may be moved to Category 4a… Water bodies remain on Category
4a of the list until compliance with water quality standards is achieved.” After compliance is
achieved, is the TMDL designation removed or does it continue indefinitely?

The TMDL designation can be removed for this pollutant after standard are achieved. The
assessment unit may remain in category 4a if other TMDL apply.

Comment 4. Page 12: In the third paragraph the report states “The DWQ conducted a special
study in the Haw River… for a six-week period from 01/06/04 to 01/16/04.” I assume that the
dates run into February.

Yes, the special study was conducted from 01/06/04 to 02/16/04. The study date is corrected in
the final TMDL document.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
90
Comment 5. Page 13: The turbidity equation relating turbidity to flow has an R-square value of
0.66. At what point does DWQ consider the R-square to be too weak to show a causal
relationship? The graph presented on this page looks like the data fits better than suggested by
the formula.

There is no fixed value that defines strength or weakness among variables. However, in theory,
the correlation (relationship) between two variables is considered strong when their correlation
( r ) approaches to 1. In this study, the correlation between NTU and flow was 0.81 (r = Square
Root of R-Square), which is high enough to justify a significant causal relationship between
turbidity and flow for this study. The graph presented in Figure 1.7 shows the significant
correlation.

Comment 6. Page 14: The water quality standard for turbidity states, “…if turbidity exceeds
these levels due to natural background conditions, the existing turbidity level cannot be
increased.” This implies that turbidity can exceed 50 NTU and not violate the water quality
standard. The regulation also states that implementation of BMP’s will be considered as
compliance with the water quality standard (page 25 of the report).

It is correct that turbidity could exceed 50 NTU under natural background conditions. In this
study, however, the background turbidity level did not exceed 50 NTU. Largest part of TSS
loads was below the targeted line during all flow conditions.

It is also correct that according to 15A NCAC 02B.0211 (3) (K) implementation of BMP’s would
be considered as compliance with the water quality standard.

Comment 7. Page 14: The water quality standard for fecal coliform states that violations of the
standard are expected during rainfall events and “… this violation is expected to be caused by
uncontrollable nonpoint source pollution…”

This study assumes that uncontrollable non-point source pollution would occur during heavy
rainfall events. Therefore, the fecal coliform load during above 90th percentile flow event was
not considered in the TMDL estimation.

Comment 8. Page 16: Based on the 2002 data, is it possible that there was one year or a series
of rainfall events during the 1997 – 2003 period that is responsible for the bulk of the fecal
coliform exceedances? The fecal coliform data for 2002 look very good.

This TMDL was developed based on the instantaneous monthly measurements. The
measurement suggested that the fecal coliform exceeded 400 counts / 100 ml in more than 20%
of the sample examined during the study period.

Turbidity and Fecal Coliform TMDL: Haw River, Deep River, Third Fork Creek, and Dan River
91
Comment 9. Page 24: The summary of the NPDES permit conditions is incorrect. The TSS
(45 mg/L) and Fecal Coliform limits (400 cfu/100 mL geometric mean) in the permits are
weekly averages. There are no daily maximums in the NPDES permits for these parameters.

There are daily maximums in the NPDES permits for these parameters. In general, privately
own industries are permitted under daily maximum limit, whereas publicly own industries are
permitted under weekly average limit. Daily Maximum limits are possible as the result of this
TMDL. The summary tables of the NPDES permit in this study are revised accordingly.

Comment 10. Page 28: The formula for the relationship of TSS and turbidity has an R-square
of 0.57. Again, this is not a very strong correlation.

The relationship is moderate, because correlation (r ) is estimated at 0.75 (r = Square Root of R-
Square value). Therefore, the relationship between TSS and NTU can be justified for this study.

Comment 11. Page 32: After converting turbidity NTU to TSS loading, there were no
violations during typical and low flows. This suggests that some of the problem could be (is)
related to natural, uncontrollable conditions during heavy rains.

In this study, turbidity measurement during above 90th percentile flow (high flow) period was not
considered in order to exclude natural, uncontrollable conditions in the TMDL estimation.