EastForkDeepRiverTMDLsFinal

Total Maximum Daily Loads for
Turbidity and Fecal Coliform for
East Fork Deep River, North Carolina
[Waterbody ID 17-2-(0.3) and
Waterbody ID 17-2-(0.7)]

Final Report
February 2004
(Approved March 2004)

Prepared by:
NC Department of Environment and Natural Resources
Division of Water Quality
1617 Mail Service Center
Raleigh, NC 27699-1617

With support from:
TetraTech, Inc.
3200 Hwy 54
Cape Fear Bldg., Suite 105
Research Triangle Park, NC 27709
NC DWQ Contract Number EW030318, Project Number 1-4
Cape Fear River Basin

East Fork Deep River Watershed TMDLs February 2004

i
Table of Contents
List of Tables iii
List of Figures iv
1 Introduction..................................................................................................................1
1.1 Problem Definition........................................................................................................................ 1
1.1.1 TMDL Components.............................................................................................................. 2
1.1.2 East Fork Deep River Turbidity and Fecal Coliform Impairments....................................... 2
1.2 Watershed Description.................................................................................................................. 4
1.2.1 Landuse Distribution in the East Fork Deep River Watershed............................................. 4
1.3 Water Quality Monitoring............................................................................................................. 5
1.3.1 NCDENR Monitoring........................................................................................................... 5
1.3.2 PTCOG Fecal Monitoring Data............................................................................................ 6
2 Source Assessment.......................................................................................................8
2.1 General Sources of Turbidity ........................................................................................................ 8
2.1.1 Nonpoint Sources of Turbidity............................................................................................. 8
2.1.2 Point Source Turbidity Contributions................................................................................... 9
2.2 General Sources of Fecal Coliform............................................................................................... 9
2.2.1 Nonpoint Source Fecal Coliform Contributions................................................................... 9
2.2.2 Point Source Fecal Coliform Contributions........................................................................ 12
3 Technical Approach...................................................................................................14
3.1 TMDL Endpoints ........................................................................................................................ 14
3.1.1 Endpoint for Turbidity TMDL............................................................................................ 14
3.1.2 Endpoints for Fecal Coliform TMDL................................................................................. 14
3.2 Flow-Duration Curves for Turbidity and Fecal Coliform ........................................................... 15
3.3 Assimilative Capacity ................................................................................................................. 18
3.3.1 Determination of Existing TSS Load and Assimilative Capacity....................................... 18
3.3.2 Determination of Existing Fecal Coliform Load and Assimilative Capacity ..................... 19
4 TMDL Development..................................................................................................22
4.1 TMDL Definition........................................................................................................................ 22
4.2 TMDL Endpoints ........................................................................................................................ 22
4.3 Critical Conditions ...................................................................................................................... 22
4.4 Seasonal Variations..................................................................................................................... 22
4.5 Margin of Safety (MOS) ............................................................................................................. 23
4.6 TMDL Curves............................................................................................................................. 23
4.6.1 TMDL Curve for Turbidity ................................................................................................ 23
4.6.2 TMDL Curves for Fecal Coliform...................................................................................... 24
4.7 TMDL Summary......................................................................................................................... 26
5 Report Summary........................................................................................................28
6 TMDL Implementation Plan......................................................................................29
7 Stream Monitoring.....................................................................................................31
8 Future Efforts.............................................................................................................33
9 Public Participation....................................................................................................35
East Fork Deep River Watershed TMDLs February 2004

ii
10 Further Information.................................................................................................... 37
11 References 39
12 Appendices 42
Appendix A Water Quality Sampling Data .................................................................45
Appendix B Load Reduction Calculations .................................................................. 52
Appendix C Affidavits of Publication for Public Notice............................................. 60
East Fork Deep River Watershed TMDLs February 2004

iii
List of Tables
Table 1. East Fork Watershed MRLC Landuse Acreage and Percent Composition...................4
Table 2. Summary of NCDENR Water Quality Monitoring for Turbidity and Fecal
Coliform Impairment.....................................................................................................6
Table 3. Summary of PTCOG Fecal Coliform Monitoring Data................................................7
Table 4. 1990 and 2000 Census Data for Sewage Disposal by Housing Unit (HU) and
Population Density for the East Fork Deep River.......................................................10
Table 5. Flow Statistics for USGS Gage 02099000..................................................................15
Table 6. TMDL Reductions for TSS and Fecal Coliform.........................................................26
Table 7. Relative Pollutant Contributions Rates.......................................................................27
Table 8. East Fork Deep River TMDL Components.................................................................27
Table 9. NCDENR Monitoring Data for Station B4240000 near
Wendover Ave. (1997-2002).......................................................................................47
Table 10. PTCOG Fecal Coliform Monitoring Data 2001-2003 ................................................49
Table 11. Estimation of Load Reduction for Turbidity (lb/day TSS).........................................54
Table 12. Estimation of Load Reduction (#/day) based on Fecal Coliform Instantaneous
Standard.......................................................................................................................55
Table 13. Estimation of Load Reduction (#/day) based on Fecal Coliform Geometric Mean
Standard.......................................................................................................................56
Table 14. Estimates of TSS and Fecal Coliform Runoff Loading Rates for Urban and Rural
Lands...........................................................................................................................57
Table 15. Estimates of Direct Fecal Coliform Contribution from Urban Sources......................57
Table 16. Relative Urban and Rural TSS Areal Loading............................................................57
Table 17. Relative Urban and Rural FC Areal Loading..............................................................58

East Fork Deep River Watershed TMDLs February 2004

iv
List of Figures
Figure 1. Location of East Fork Deep River........................................................................................ 1
Figure 2. Extent of Fecal Coliform and Turbidity Listed Segments.................................................... 3
Figure 3. East Fork Deep River MRLC Landuse Overlaid with Greensboro and High Point
Planimetric Data ................................................................................................................... 5
Figure 4. NCDENR and PTCOG Monitoring Locations..................................................................... 6
Figure 5. PTCOG High Flow Period Fecal Coliform Monitoring Data (10/1/02 – 12/31/02)............. 7
Figure 6. Location, Description, and Date of Sanitary Sewer Overflows (SSOs) and Census Block
Boundaries.......................................................................................................................... 12
Figure 7. Regression of TSS (mg/L) on Turbidity (NTU) R2=0.54, p<0.001.................................... 15
Figure 8. Turbidity Flow-Duration Curve at NCDENR Station B424000......................................... 16
Figure 9. TSS Flow-Duration Curve at NCDENR Station B424000................................................. 17
Figure 10. Fecal Coliform Flow-Duration Curve at NCDENR Station B424000 ............................... 17
Figure 11. Flow-Duration Curve For PTCOG Fecal Coliform Data ................................................... 18
Figure 12. Load-Duration Curve for TSS ............................................................................................ 19
Figure 13. Instantaneous Fecal Coliform Load-Duration Curves........................................................ 20
Figure 14. Geometric Mean Fecal Coliform Load-Duration Curves................................................... 20
Figure 15. TMDL Curve Based on TSS Surrogate Standard for Turbidity ......................................... 24
Figure 16. TMDL Curve Based on Instantaneous Fecal Coliform Standard, Exceedances Circled.... 25
Figure 17. TMDL Curve Based on Geometric Mean Fecal Coliform Standard.................................. 25

East Fork Deep River Watershed TMDLs February 2004

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SUMMARY SHEET
Total Maximum Daily Load (TMDL)

1. 303(d) Listed Waterbody Information
State: North Carolina
County: Guilford
Major River Basin: Cape Fear River Basin
Watershed: East Fork Deep River – in Deep River Watershed HUC 03030003

Impaired Waterbody (2000 303(d) List):
Waterbody Name - (ID)Water Quality Classification Impairment Length (mi)
East Fork Deep River -
17-2-(0.3)
WS-IV - Aquatic life and
secondary contact recreation Fecal Coliform 6.5
East Fork Deep River -
17-2-(0.3)
WS-IV - Aquatic life and
secondary contact recreation Turbidity 6.5
East Fork Deep River -
17-2-(0.7)
WS-IV CA - Aquatic life and
secondary contact recreation Turbidity 0.6

Constituent(s) of Concern: Fecal Coliform Bacteria, Turbidity
Designated Uses: Biological integrity, propagation of aquatic life, and recreation.
Applicable Water Quality Standards for Class C Waters:
Fecal coliforms shall not exceed a geometric mean of 200/100ml (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: not to exceed 50 NTU
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 for in the load curve analysis by determining the average
difference between the existing load violation trend line and the allowable load line. This approach
was chosen because existing load violations occur at all flow levels.

East Fork Deep River Watershed TMDLs February 2004

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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.
3. Allocation Watershed/Stream Reach
Pollutant Existing WLA1 LA MOS2 TMDL Reduction
Required
TSS (lb/day) 3 2,564.6 77.9 895.4 Explicit 10% 973.3 62%
Fecal coliform
(counts/day) 7.3x1011 9.2x1010 8.8x1010 Explicit 10% 1.8x1011 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: 12/10/2003
5. Submittal Date: 2/13/2004
6. Establishment Date: 3/4/2004
7. Endangered Species (yes or blank):
8. EPA Lead on TMDL (EPA or blank):
9. TMDL Considers Point Source, Nonpoint Source, or both: both

East Fork Deep River Watershed TMDLs February 2004

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1 Introduction
This report presents the development of Total Maximum Daily Loads (TMDLs) for fecal coliform and
turbidity impairments of the East Fork Deep River. The East Fork of the Deep River near Greensboro,
North Carolina has been placed on the North Carolina 2002 list of impaired waters (the 303(d) list) and
requires estimation of a Total Maximum Daily Load for turbidity and fecal coliform in order to meet the
water quality standards specified for WS-IV and WS-IV CA waters. The East Fork Deep River is a
headwater tributary to the Deep River and is located entirely within Guilford County, North Carolina
(Figure 1) and drains an area of approximately 14.8 square miles.

Greensboro
High Point
East Fork Deep River
Wendover Ave.
NC
-
6
8
I-40
High Point Lake
0 1 2 3 Miles
0 100 200 Miles
Guilford County Jurisdiction
Municipalities
Streams
Waterbodies
Roads
Watershed Boundary
USGS 1:24,000 K Hydrography
Location of East Fork Deep River
in the Cape Fear River Basin
LEGEND
N

Figure 1. Location of East Fork Deep River
1.1 PROBLEM DEFINITION
Section 303(d) of the Clean Water Act (CWA) requires states to develop a list of waters not meeting
water quality standards or which have impaired uses. This list, referred to as the 303(d) list, is submitted
biennially to the U.S. Environmental Protection Agency (EPA) for review. Development of a TMDL
requires an assessment of the assimilative capacity of the stream, assessment of the sources within the
watershed contributing to the total instream load, and a recommendation of the reductions required from
each source.
East Fork Deep River Watershed TMDLs February 2004

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1.1.1 TMDL Components
The 303(d) process requires that a Total Maximum Daily Load (TMDL) be developed for each of the
waters appearing on Part I of the 303(d) list. The objective of a TMDL is to estimate allowable pollutant
loads and allocate 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 EPA (1991, 2000) and
the Federal Advisory Committee (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.
Reduction target. Estimation of the level of pollutant reduction needed to achieve water quality goal. The
level of pollution should be characterized for the waterbody, 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 wasteload 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, stormwater, and natural background.
Margin of Safety. The margin of safety addresses uncertainties associated with pollutant loads, modeling
techniques, and data collection. Per EPA (2000), 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).
Critical Conditions. Critical conditions indicate the combination of environmental factors that result in
just meeting the water quality criterion and have an acceptably low frequency of occurrence.
Section 303(d) of the CWA and the Water Quality Planning and Management regulation (USEPA, 2000)
require EPA to review all TMDLs for approval or disapproval. Once EPA approves a TMDL, then the
waterbody may be moved to Category 4a of the Integrated Report. Waterbodies remain in Category 4a
until compliance with water quality standards is achieved. Where conditions are not appropriate for the
development of a TMDL, management strategies may still result in the restoration of water quality.
1.1.2 East Fork Deep River Turbidity and Fecal Coliform Impairments
The State of North Carolina has identified the segment within the East Fork Deep River watershed as
being impaired by fecal coliform and turbidity. The listings are contained in the North Carolina Water
Quality Assessment and Impaired Waters List (2002 Integrated 305(b) and 303(d) Report). The East
Fork of the Deep River near Greensboro, North Carolina has been placed on the North Carolina 2002 list
of impaired waters (the 303(d) list) and requires estimation of a Total Maximum Daily Load for turbidity
and fecal coliform in order to meet the water quality standards specified for a WS-IV water. The
segments of East Fork considered to be impaired due to turbidity [Waterbody ID 17-2-(0.3) and 17-2-
(0.7)] extend 7.1 miles from the headwaters down to the inlet for High Point Lake (Figure 2). The fecal
coliform impairment extends for 6.5 miles from the headwaters to a point 0.4 miles downstream of SR-
1541 [Waterbody ID 17-2-(0.3)].

East Fork Deep River Watershed TMDLs February 2004

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Figure 2. Extent of Fecal Coliform and Turbidity Listed Segments
The East Fork Deep River has a designated use classification of WS-IV which is intended to protect
drinking water supplies. This designation also encompasses the more general Class C requirements that
protect aquatic life and secondary contact recreation (NCDENR, 2003). The North Carolina fresh water
quality standard for fecal coliform in Class C waters (T15A:02B.0211) states:
Organisms of the coliform group: fecal coliforms 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; 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.
The North Carolina water quality standard for turbidity is stated as follows:
The turbidity in the receiving water shall not exceed 50 Nephelometric Turbidity Units (NTU)
in streams not designated as trout waters.
East Fork Deep River
Nc Hwy 68
I-40
Wendover Ave.
East Fork Deep River
Wendover Ave.
NC
-
6
8
I-40
0 1 2 Miles
N
Listed for
Fecal Coliform
Listed for
Turbidity
303d Listed Stream
East Fork Deep River Watershed TMDLs February 2004

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1.2 WATERSHED DESCRIPTION
The East Fork Deep River is located entirely within Guilford County, North Carolina (Figure 1). The
East Fork extends 7.1 miles from its headwaters in western Greensboro to its entrance into High Point
reservoir and includes approximately 18 miles of mainstem and tributary stream reaches. The river drains
approximately 14.8 square miles of land, including sections of the cities of Greensboro and High Point.
1.2.1 Landuse Distribution in the East Fork Deep River Watershed
The Multi-Resolution Landuse Classification (EPA, 2000) dataset was used to determine the landuse
distribution within the watershed. This dataset was developed using satellite data collected during the
period from 1992 – 1993. As shown in Table 1, agricultural and forested areas dominate the landuse.
However, significant development has occurred in the watershed in recent years and resulted in
conversion of large rural parcels into residential and commercial areas. In Figure 3, the 1995 Greensboro
planimetric data and a recent High Point buildings coverage overlays the MRLC landuse, providing a
more accurate view of the development in the watershed. Informal windshield surveys in the watershed
indicate that urbanization has continued since the Greensboro and High Point data were collected.
Conversion of rural areas to urban landuses, including highways, can be a significant source of sediment
during the construction phase. In addition, the higher imperviousness of the new landuse increases urban
runoff volumes and results in erosion of surface soils and stream channels. The conversion of rural
landuses will shift the nonpoint source contribution of fecal coliform from agricultural activities such as
cattle grazing and manure application to urban sources such as fecal waste from household pets, sanitary-
sewer overflows (SSOs), and leaking sewer lines.
The population density within the watershed grew from 166 people per square mile to about 340 people
per square mile between 1990 and 2000 (U.S. Census, 1990 and 2000). As residential and commercial
areas grew, the High Point and Greensboro municipal boundaries were expanded, new sewer lines were
added, and septic systems were phased out. It is likely that a majority of the households now have sewer
service; a review of the 1995 Guilford County Atlas shows that the entire watershed lies within either the
existing or proposed sewer service areas.
Table 1. East Fork Watershed MRLC Landuse Acreage and Percent Composition
Landuse Barren Agriculture Pasture Forest Urban Water/
Wetland Total
Area (ac) 13 3,507 682 4014 1158 0 9,479
Area (%) 0.1 37.0 7.2 42.4 12.2 1.1 100

East Fork Deep River Watershed TMDLs February 2004

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Figure 3. East Fork Deep River MRLC Landuse Overlaid with Greensboro and High Point
Planimetric Data
1.3 WATER QUALITY MONITORING
Water quality monitoring performed by NCDENR for turbidity and fecal coliform have shown occasional
excursions above the water quality standard. Additional fecal coliform monitoring data, collected by the
Piedmont-Triad Council of Governments (PTCOG), further supports the decision to list the East Fork
Deep River for fecal coliform impairment.
1.3.1 NCDENR Monitoring
Water quality monitoring for the East Fork was performed by NCDENR at Station B424000 near
Wendover Avenue (Figure 4). Regular monitoring was performed for the period from 1/23/1997 through
9/18/2001. These data were collected approximately monthly and include observations for fecal coliform,
turbidity, total residue, specific conductance, and total suspended solids. Additional intensive fecal
coliform monitoring was performed during the period from 4/4/2002 through 5/16/2002 to assess the
impairment status with regards to the standards specification requiring five samples per 30-day period.
Table 2 presents a summary of the fecal coliform and turbidity data collected. It should be noted that the
exceedance count does not consider the requirement that five samples must be taken within a 30-day
period.

Listed for
FC and Turbidity
Listed for
Turbidity
N
MRLC Land Cover
Open Water
Low Intensity Residential
High Intensity Residential
Commercial/Industrial
Bare Rock/Sand/Clay
Quarries/Pits
Transitional
Decidious Forest
Evergreen Forest
Mixed Forest
Pasture/Hay
Row Crops
Other (Managed) Grasses
Woody Wetlands
Emergent Herbaceous Wetlands
USGS 1:24,000 K Hydrography
Streams
303d Listed Stream
Watershed Boundary
Roads
0 1 2 3 Miles
East Fork Deep River Watershed TMDLs February 2004

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Table 2. Summary of NCDENR Water Quality Monitoring for Turbidity and Fecal Coliform
Impairment
Parameter Period Number of Samples Number greater than standard
Turbidity 1/97 – 9/02 63 7 a
Fecal coliform 1/97 – 9/02 57 9 b
Fecal coliform 4/02 – 5/02 10 2 b
Fecal coliform 4/02 – 5/02 4 2 c
a Turbidity measurements > 50 NTU b Instantaneous fecal coliform measurements > 400 cfu/100 mL
c 30-day Geometric mean of fecal coliform measurements > 200 cfu/100 mL
1.3.2 PTCOG Fecal Monitoring Data
The Piedmont Triad Council of Governments (PTCOG) also undertook monitoring from 4/9/01 through
1/16/03 in the East Fork watershed to assess fecal coliform impairment and to identify potential sources.
A summary of the monitoring efforts and conclusions are presented in Identification of Fecal Coliform
Bacteria Sources for North Carolina 303(d) Listed Waters in Greensboro and High Point (PTCOG,
2003). A formal Quality Assurance Program Plan, included with the report, was submitted to NCDENR
to provide the quality-control documentation required for the data to be accepted as “certified.” Fecal
coliform data were collected at five primary and twenty-one secondary watershed stations (Figure 4). A
summary of the data collected in the East Fork watershed as part of the PTCOG study is presented in
Table 3. It should be noted that the exceedance count includes all data collected and does not consider the
requirement that five samples must be taken within a 30-day period.











East Fork Deep RiverNC
-
6
8
I-40

Thatcher Rd.
Gallimore Dairy
Piedmont Parkway
Wendover Ave.
B424000

Albert Pick
LEGEND
Monitoring Locations

USGS 1:24,000 K Hydrography
Census Block Group Boundaries
(watershed boundary divides
census block groups)
Roads
Waterbodies
Streams
Municipalities
Guilford County Jurisdiction
0 1 2 3 Miles
N

Figure 4. NCDENR and PTCOG Monitoring Locations

East Fork Deep River Watershed TMDLs February 2004

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Table 3. Summary of PTCOG Fecal Coliform Monitoring Data
Station Number of Samples Number Greater Than Standard a
Thatcher Road - Primary Station 36 6
Thatcher Road - All Stations 9 8
Albert Pick - Primary Station 39 14
Albert Pick - All Stations 32 22
Gallimore Dairy - Primary Station 34 14
Gallimore Dairy - All Stations 24 13
Piedmont Parkway - Primary Station 30 6
Wendover Avenue - Primary Station 35 5
a Instantaneous fecal coliform measurements > 400 cfu/100 mL

Data collected at the PTCOG water quality monitoring stations during 2002 show an increase in fecal
coliform concentrations during storm events (Figure 5). However, occasional exceedances during typical
and low flow periods indicate that intermittent, direct contributions of fecal coliform are likely to
contribute to instream impairment. Analysis of the data shows a high correlation between fecal coliform
concentrations at each station. This result is not surprising as the flow from each segment contributes to
the total flow in the downstream reach. It does, however, show that the fecal coliform concentration in
each reach is highly dependent on the upstream contributions and also shows that problems in the
headwaters (e.g., Albert Pick, Gallimore Dairy) may contribute to elevated levels in all the reaches.
Comparison of Fecal Coliform Concentrations at
East Fork Monitoring Locations (10/02 - 12/02)
1
10
100
1000
10000
100000
10/1/2002 10/15/2002 10/29/2002 11/12/2002 11/26/2002 12/10/2002 12/24/2002
Fe
c
a
l

c
o
l
i
f
o
r
m

(
#
/
1
0
0
m
L
)
Flow (cfs) (USGS02099000)
Thacker Rd
Albert Pick
Gall. Dairy
Pied. Pkw y
Wendover

Figure 5. PTCOG High Flow Period Fecal Coliform Monitoring Data (10/1/02 – 12/31/02)

East Fork Deep River Watershed TMDLs February 2004

8
2 Source Assessment
A critical step in developing a useful and defensible TMDL is the assessment of potential sources. A
watershed-wide review was performed to assess sources that potentially contribute to high turbidity and
fecal coliform loading. This review included data from the National Pollutant Discharge Elimination
System, septic use and public sewer boundaries, and landuse/landcover information. Geographical
information systems and digital orthophotos were used to gain an understanding of the sources within the
watershed. Discussion with local jurisdictions and field personnel were also used to identify and quantify
potential sources. A study by the Piedmont Triad Council of Governments was recently completed,
which aided significantly in the understanding of the potential sources in the watershed.
2.1 GENERAL SOURCES OF TURBIDITY
2.1.1 Nonpoint Sources of Turbidity
Both point and nonpoint sources may contribute to turbidity in waterbodies. Potential sources of turbidity
include silt and clay from watershed and stream erosion, organic components from detritus, and algal
matter. In rural areas, runoff can transport significant loads of sediment from natural sources and
agricultural activities. Construction activities in developing areas and stormwater runoff from urban areas
are also significant contributors of sediment washoff. A landuse map of the East Fork Deep River
watershed is presented in Figure 3. In the early 1990’s when the landuse data was developed, the
predominant landuses were forest and agriculture, 42 percent and 37 percent respectively. In recent years
much of the rural area has been converted to urban residential and commercial landuses.
Rural Sources
Turbidity loading from rural sources is primarily due to erosion of soil from forest and agricultural areas.
Although forest runoff in general produces little to no sediment load, forest-disturbing activities such as
tree harvesting, site preparation, and reforesting can have high loading rates. A review of active
harvesting may provide information on the extent of the contributions from this landuse.
Nonpoint source contamination from agriculture originates primarily from storm event runoff. A number
of factors influence the extent of erosion including erodability of the soils, types of agricultural practices,
crop type, rainfall, and the existence and type of agricultural BMPs.
Urban Runoff and Stream Channel Erosion
Significant development has been occurring in the East Fork watershed. This usually results in a decrease
in low-flow volumes and an increase in high-flow volumes. These changes are caused by the shift of
landuse in the watershed from pervious land such as forest to more impervious areas such as roads,
driveways, and parking lots. As imperviousness increases, there is less opportunity for infiltration into
the soil layer causing reduced groundwater recharge and resulting baseflow volumes. Highly impervious
areas also reduce the time of concentration and increase peak flow and velocity. A large fraction of the
rainfall during a storm event is infiltrated in the soil in naturally vegetated areas. As the impervious area
increases, rainfall events produce high intensity, short duration runoff events which increase the potential
for erosion and are capable of transporting higher amounts of sediment from the watershed to the stream.
The increase in peak flow and velocity results in an increase in bank failure, which is frequently a more
important source of total sediment in urban streams than sediment from upland areas. Bank erosion is,
however, difficult to quantify on a watershed scale. During a high-volume storm, discharge increases and
the stream becomes deeper as it fills its banks. When the water level in the stream is at the top of the
bank, the flow is termed bankfull discharge. Streams have tremendous erosive power at this stage, and
flows that form new channels are often associated with discharges greater than bankfull. In undisturbed
East Fork Deep River Watershed TMDLs February 2004

9
watersheds, flows in excess of bankfull spill over into the floodplain, and high-energy flows are
dissipated over a larger area. As a result, velocity, shear stress, and erosive power decline dramatically.
In more urbanized watersheds, stream incision often prevents access to the floodplain, and streams are
unable to dissipate their energy during high-flow events. Stream bank failure is common in urban
systems where stream hydrographs have been altered due to an increase in impervious cover. Removal of
riparian trees during development exacerbates the problem by decreasing stability provided by root
systems.
Construction
According to the Greensboro Sediment and Erosion Control department, construction is the major source
of sediment in the watershed (Cook, 2003). Land clearing and site preparation for the development of
residential buildings, commercial areas, roads, and highways increase the erosion potential of soils.
Vegetative cover is lost and the soil surface is often disturbed allowing for greater exposure to rainfall and
greater chance of rill and gully erosion. Soil loss rates from construction sites can be many times higher
than natural sites when erosion controls are not required or correctly maintained.
2.1.2 Point Source Turbidity Contributions
Urban stormwater runoff can contribute significant amounts of turbidity to the East Fork. However,
much of this runoff is regulated in compliance with the NPDES Storm Water Phase I and Phase II progam
(EPA, 2000). This rule applies to a unit of government such as a city or county, which owns or operates a
municipal separate storm sewer system (MS4). The MS4 is required to obtain a National Point Source
Discharge Elimination System (NPDES) permit for their stormwater discharges to surface waters. As
such, stormwater runoff from areas within an MS4 is considered a point source. The City of Greensboro,
City of High Point, and Guilford County fall under the NPDES stormwater rules and therefore maintain a
stormwater management programs. There are no continuous point sources in the watershed with NPDES
permit limits for turbidity or TSS.
2.2 GENERAL SOURCES OF FECAL COLIFORM
Both point and nonpoint sources may contribute fecal coliform to the waterbodies. Potential sources of
fecal coliform loading are numerous and often occur in combination. In rural areas, runoff can transport
significant loads of fecal coliform from agricultural activities. Septic systems, illicit discharges, and
broken sewer pipes can be potential sources in urban areas.
Potential sources of fecal coliform loading in the watershed were identified based on an evaluation of
current landuse/cover, septic system/sewer use, and SSO data. The source assessment was used as the
basis of development of the model and ultimate analysis of the TMDL allocations.
2.2.1 Nonpoint Source Fecal Coliform Contributions
Research was performed to assess the most probable nonpoint sources of fecal coliform. Information on
sources was gathered from GIS information, census data, and personal communication with local and
state officials. The principal sources investigated were sewer overflows, landuse distribution, septic
systems, sewer pipe defects, and the populations of wildlife and domestic animals.
Landuse Contributions
Runoff from landuses in the watershed can be a significant contributor to fecal coliform loadings to
streams. Stormwater runoff carries wildlife and domestic animal feces into surface water. Agricultural
land near streams contributes fecal coliform from livestock and the land application of manure. Runoff
from urban surface is also a potentially significant source of fecal coliform loadings.
East Fork Deep River Watershed TMDLs February 2004

10
A landuse map of the East Fork Deep River watershed is presented in Figure 3. In the early 1990s when
the landuse data was developed, the predominant landuses were forest and agriculture, 42 percent and 37
percent respectively. In recent years much of the rural area has been converted to urban land such as
residential and commercial landuses. The Greensboro and High Point planimetric data is overlayed with
the landuse data in Figure 3 to show more recent development.
From inspection of the landuse figure, it is apparent that forest dominates the streamside contribution to
the system. Forest surrounds the downstream portion of the East Fork, especially from Piedmont
Parkway to the outlet. In this portion of the watershed, wildlife feces in runoff may be a frequent cause of
fecal coliform loading. Row crop landuses and some pasture also exist alongside streams in the
watershed. These landuses contribute fecal coliform from livestock and manure application. Residential
areas are dispersed throughout the watershed, but several housing developments exist near the stream
between Piedmont Parkway and Wendover Avenue. These developments probably contribute some fecal
coliform from family pets.
According to the monitoring data, fecal coliform exceedances in the East Fork Deep River occurred most
often during high flow events. Where fecal coliform is not directly attributed to SSOs, it is likely that a
combination of urban runoff and animal populations has caused the fecal coliform exceedances.
Septic Systems
Septic tanks were considered a potential source of fecal coliform to the streams during low flow events.
The 1990 census and digitized Greensboro sewer lines were used to assess the remaining number of septic
tanks in the watershed1. The census block groups divide the watershed into four portions defined by the
intersection of Interstate 40 and State Highway 68: Northwest, Southwest, Northeast, and Southeast.
Table 4 summarizes the population densities and housing units served by either septic systems or sewer
service in each of the four quadrants.
Table 4. 1990 and 2000 Census Data for Sewage Disposal by Housing Unit (HU) and
Population Density for the East Fork Deep River
Sewer 1990
(HU/mi2)
Septic 1990
(HU/mi2)
Population
Density 1990
(persons/mi2)
Population
Density 2000
(persons/mi2)
Northwest <6 6-256 64-166 134
Southwest 6 45 141 301
Northeast 160 13 275 378
Southeast 90 38 224 339

A large percentage of the Northwest portion had the lowest density of housing units using septic tanks in
1990. The recent Greensboro sewer lines extend throughout this area, suggesting that most residential
areas are using the sewer system or are in the process of converting. In the City of Greensboro, residents
are required to switch from septic to sewer systems within 5 years of the sewer line extension. Houses
with defective septic tanks may be required to connect immediately, while elderly or low-income
residents may be given more time to connect (Peacock, 2003). However, in one census block group in the
Northwest portion, a reported value of 256 septic tanks per square mile was given. It is likely that this
high number actually reflects the more rural parts of the census block group and not the small section in
this watershed.

1 The 2000 Census did not collect information on sewage disposal.
East Fork Deep River Watershed TMDLs February 2004

11
The Eastern portions of the watershed have the highest population density. The majority of 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. Therefore, septic tanks are an unlikely source in the Eastern half
of the watershed.
The Southwest portion of the watershed had the highest septic-tank density of 45 housing units per square
mile. About one half of the census block group is within the East Fork watershed. This area includes
recent expansion of High Point as well as the 1995 proposed sewer service area of Guilford County
(Guilford County, 1995). The High Point buildings coverage shows that development remains widely
dispersed and that most houses may continue to use septic tanks. If these septic tanks were contributing
fecal coliform to the East Fork, low flow exceedances would occur frequently. Instead, low flow
exceedances are infrequent, which suggests that septic tanks are not causing high fecal coliform
concentrations.
Given the low number of septic tanks in the county (U.S. Census, 1990) and the locations relative to the
East Fork Deep River watershed, septic tanks were not considered primary sources in the loading
analysis. Septic tank contributions of fecal coliform were considered negligible in comparison to other
nonpoint sources.
Sewer Overflows
Fecal coliform may enter surface water when sewer pipes are clogged, damaged, 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). Figure 6 shows the locations of known SSOs
affecting surface water in Greensboro between 1998 and 2003 (Phlegar, 2003). Most SSOs reported for
Greensboro were blockages or damage that are not likely to reoccur. The Albert Pick Lift Station is the
only reoccurring SSO, and eight out of the thirteen overflows were due to high rain events. Within the
City of High Point, no known SSOs or other sewer problems have occurred in the East Fork watershed
within the last 3 years (Hepler, 2003).
The Albert Pick Lift Station SSOs are likely sources of high flow fecal coliform exceedances. This lift
station is located near the East Fork main stem upstream of the Gallimore Dairy Road monitoring site.
These SSOs were likely to contribute to high flow exceedances at the Gallimore Dairy Road site.
A sewer-line force-main break in 2001 may explain some of the four normal flow and three low flow
fecal coliform exceedances. At Gallimore Dairy Road, exceedances from June through October 2001
were probably caused by the sewer break South of Albert Pick Road (Patrick, 2003). Construction
equipment on I-40 damaged the sewer force main during the summer of 2001, and the sewer was not
repaired until October 2001.
The SSOs do not directly explain the remaining normal and low-flow exceedances. Most of these
exceedances originated at the Albert Pick Road site, and a few exceedances originated at the Thatcher
Road site. Clogged sewer pipes have been reported in these areas, and clogged pipes may have
contributed to these exceedances.
East Fork Deep River Watershed TMDLs February 2004

12

Figure 6. Location, Description, and Date of Sanitary Sewer Overflows (SSOs) and
Census Block Boundaries

Sewer Defects
Defects in sewer pipes, including cracked and corroded pipes, allow sewage to leak into surface water.
Sewer pipe leaks are a likely cause of low flow fecal coliform exceedances as they contribute high loads
during periods where there is a minimal amount of stream flow to dilute their contribution. Other
potential sources like illicit discharges and septic tanks are not as likely because the exceedances would
reflect a continuous load.
In its July 2003 report on fecal coliform sources, PTCOG did not find any known sewer defects in the
East Fork watershed. One exception was a sewer break in the Gallimore Dairy watershed that was
reported as an SSO and repaired. The Albert Pick and Gallimore Dairy subwatersheds were chosen to
conduct an updated assessment of sewer defects since these subwatersheds experience the most fecal
coliform exceedances. Charles Pegram of the City of Greensboro reported that no recent surveys had
been conducted in these subwatersheds and that he was not aware of any sewer leaks (Pegram, 2003).
The occasional, low flow exceedances are probably caused by unknown sewer leaks.
2.2.2 Point Source Fecal Coliform Contributions
As mentioned in Section 2.1.2, the City of Greensboro, City of High Point, and Guilford County are
required to implement programs under the Phase II Stormwater Rule (Greensboro is also a Phase I city).
As such, loadings of fecal coliform from stormwater runoff are considered to be point source discharges
for the purpose of the TMDL. There are no NPDES continuous point source discharges permitted to
discharge fecal coliform in the watershed.

East Fork Deep River
Wendover Ave.
NC
-
6
8
I-40
Rocks clogged
8" sewer main
(March 2003).
Contractor damaged
sewer force main
(September and
October 2001).
Broken air valve
(February 2003).
Albert Pick
Lift Station
(1998-2003).
Mud and rocks
clogged sewer
(January 2002).
Guilford County Jurisdiction
Municipalities
Streams
Waterbodies
Roads
Census Block Group Boundaries
(watershed boundary divides
census block groups)
USGS 1:24,000 K Hydrography
Location of Sanitary Sewer Overflows
LEGEND
0 1 2 3 Miles
N
East Fork Deep River Watershed TMDLs February 2004

13
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East Fork Deep River Watershed TMDLs February 2004

14
3 Technical Approach
Given the results of the initial data analysis and time and budget constraints, an approach focusing on the
magnitude of water quality standard exceedances and potential sources contributing to the stream during
the exceedances was used. This approach used a flow-duration curve analysis to determine the flow
conditions under which impairment occurs. In addition, the approach was used to identify source types,
specify the assimilative capacity of the stream, and estimate the magnitude of load reduction required to
meet the water quality standards. The potential sources determined from the load-duration curve were
inventoried and assessed for their relative contributions to allocate reductions among sources. The results
of this assessment were used to derive the allocations required by the TMDL.
This section describes the process used to specify the endpoints and calculate the existing loading and
assimilative capacity. The determination of the TMDL reductions and loads are presented in Section 4.
3.1 TMDL ENDPOINTS
3.1.1 Endpoint for Turbidity TMDL
Turbidity is a measure of the scattering of light as it passes through water and is reported in
Nephelometric Turbidity Units (NTU). This turbidity may come from a variety of components including
suspended sediment, organic matter, and microorganisms in the water column. Waters with high turbidity
can affect aquatic life processes, disinfection processes for drinking water supplies, and aesthetics.
However, turbidity is not a concentration and, as a measure, cannot be directly converted into loadings
required for the TMDL. For this reason, available water quality data was evaluated in order to identify a
surrogate measure, which could be used as a predictor of turbidity. NCDENR data for total residue, total
filterable residue, and total suspended solids (TSS) were processed and compared with turbidity
measurements collected on the same day. Of these measures, TSS was most highly correlated with
turbidity and was a significant explanatory variable (p<0.001). TSS was therefore selected as the
surrogate measure for turbidity and used to develop the TMDL target and limits (USEPA 1999).
A regression of TSS on turbidity was used to estimate the median TSS at the turbidity standard of 50
NTU. The regression used natural log transformations of TSS and Turbidity monitoring data from 1997
through 2002. Median TSS at 50 NTU will occur between 16 and 34 mg/L in 95% of samples. The
estimated median TSS for the turbidity standard is 23 mg/L TSS. The regression results are shown in
Figure 7.
3.1.2 Endpoints for Fecal Coliform TMDL
The achievement of the TMDL objectives require the instream concentrations to meet both the
instantaneous standard of 400 cfu/100 mL and the geometric mean standard of 200 cfu/100 mL. Both
standards are considered to be the endpoints for the determination of the fecal coliform TMDL for the
East Fork Deep River.
East Fork Deep River Watershed TMDLs February 2004

15
1
10
100
1000
1.0 10.0 100.0 1000.0
Turbidity (NTU)
TS
S

(
m
g
/
L
)
Observed TSS
Predicted TSSTSS=0.459*Turbidity1.004

Figure 7. Regression of TSS (mg/L) on Turbidity (NTU) R2=0.54, p<0.001
3.2 FLOW-DURATION CURVES FOR TURBIDITY AND FECAL COLIFORM
The analysis of pollutant levels in conjunction with water quality standards and measured flow is a useful
tool for assessing critical conditions, as well as existing and target loads. The Flow-Duration Curve
Method (Stiles 2002, Cleland 2002) was used for both TSS and fecal coliform. This method plots flow
and observed data to analyze the flow conditions under which impairment occurs and water quality
deviates from the standard. The method was used to determine the seasonality and flow regimes during
which the exceedances occur and to determine maximum daily load based on the flow duration and
applicable standard.
A flow-duration curve analysis was performed to identify the flow regimes during which exceedances of
the water quality standards occur. This method determines the relative ranking of a given flow based on
the percent of time that historic flows exceed that value. Daily gaging data for the period from 1/1929
through 12/2002 at USGS Station 02099000 was used to establish the historic flow regimes and define
ranges for the high, transitional, typical, and low flow conditions. Flow statistics for the gage are
presented in Table 5.
Table 5. Flow Statistics for USGS Gage 02099000 (E. Fork Deep at Wendover Ave.)
Flow Parameter Value (cfs)
Mean 17.4
Min 0.6
Max 1670.0
High flow range 26.0 – 1,670.0
Transitional flow range 12.0 – 26.0
Typical flow range 4.7 – 12.0
Low flow range 0.6 – 4.7
East Fork Deep River Watershed TMDLs February 2004

16
Once the relative rankings were calculated for flow, monitoring data were matched by date to compare
observed water quality to the flow regime during which it was collected. As is seen in Figure 8, this type
of analysis can help define the flow regime during which exceedances occur and also pinpoint the source
of the impairment. Exceedances that occur only during low-flow events are likely caused by continuous
or point 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 nonpoint
sources may cause exceedances during normal flows.
Review of Figure 8 indicates that the turbidity impairment occurs during high-flow events and is likely
caused by storm runoff. The majority of exceedances of the water quality standard occur during high
flow events. These exceedances also tend to occur during the summer (April through October). This type
of behavior is consistent with high sediment loadings resulting from nonpoint source summer, storm
event runoff. Streambank erosion may be a contributing factor for high values in the 0-10% interval
(Cleland, 2002). Figure 9 presents the flow duration curve for TSS and compares the monitoring data to
the surrogate target value of 23 mg/L.

East Fork Deep River at Wendover Ave
WQ Duration Curve (1997-2002 Monitoring Data)
0
20
40
60
80
100
120
140
160
0 10 20 30 40 50 60 70 80 90 100
Flow Duration Interval (%)
All
Summer
Inst. WQ Standard
Low flowsTypical High Transition
DroughtFlood

Figure 8. Turbidity Flow-Duration Curve at NCDENR Station B424000

East Fork Deep River Watershed TMDLs February 2004

17
East Fork Deep River at Wendover Ave
WQ Duration Curve (1997-2002 Monitoring Data)
0
20
40
60
80
100
120
140
160
180
200
0 10 20 30 40 50 60 70 80 90 100
Flow Duration Interval (%)
TS
S

(
m
g
/
L
)
All
Summer
Inst. WQ Target
Low flowsTypical High Transition
DroughtFlood

Figure 9. TSS Flow-Duration Curve at NCDENR Station B424000
Figure 10 shows exceedances of the instantaneous-fecal-coliform water quality standard (400 cfu/100
mL) during high-flow and typical-flow regimes, indicating contributions from moderate and high-flow-
storm events as well as some intermittent discharges. Fecal coliform concentrations are expressed as
number of colony forming units and may be written as “#/100 mL” or “cfu/100 mL.”

East Fork Deep River at Wendover Ave
WQ Duration Curve (1997-2002 Monitoring Data)
1
10
100
1000
10000
0 10 20 30 40 50 60 70 80 90 100
Flow Duration Interval (%)
Fe
c
a
l

c
o
l
i
f
o
r
m
,

c
f
u
/
1
0
0
m
L
Summer
Inst. WQ Standard
Winter
Low Typical
High Transition
DroughtFlood

Figure 10. Fecal Coliform Flow-Duration Curve at NCDENR Station B424000
Figure 11 presents the flow-duration analysis for the primary PTCOG monitoring locations. The PTCOG
monitoring data provide four additional sample sites upstream of the NCDENR station at Wendover Ave.
This higher resolution indicates that while many exceedances occur during high and transition-flow
East Fork Deep River Watershed TMDLs February 2004

18
events, fecal coliform also exceeds the instantaneous standard during typical and low flows. The PTCOG
data suggest that both storm-event runoff and low-flow sources, such as illicit discharges, septic systems,
or broken sewer lines, contribute to high fecal coliform loading in the East Fork Deep River.

East Fork Deep River
WQ Duration Curve (All Stations)
1
10
100
1000
10000
100000
0 10 20 30 40 50 60 70 80 90 100
Flow Duration Interval (%)
Fe
c
a
l

c
o
l
i
f
o
r
m

(
#
/
1
0
0
m
L
)
Albert Pick
Thacker Rd (5)
Gall.Dairy
Pied. Pkw y(2)
Wendover (1)
Inst. WQ Standard
Low flowsTypical flowsHigh
flows
Transition
flows
DroughtFlood

Figure 11. Flow-Duration Curve For PTCOG Fecal Coliform Data
3.3 ASSIMILATIVE CAPACITY
3.3.1 Determination of Existing TSS Load and Assimilative Capacity
The TSS assessment used the Flow-Duration Curve approach presented to NCDENR by Bruce Cleland.
This approach uses a flow-duration curve analysis to determine the flow conditions under which
impairment occurs. In addition, the approach is used to identify source types, specify the assimilative
capacity of the stream, and estimate the magnitude of load reduction required to meet the water quality
standards. The potential sources determined from the load-duration curve were inventoried and are
discussed in Section 4.
As discussed in Section 3.1.1, TSS was selected as a suitable surrogate for determining turbidity
impairment. Existing TSS loading to the East Fork was determined by multiplying the observed TSS data
by the flow observed on the date of the observation and converting the result to a daily loading value.
The assimilative capacity of the stream was determined by multiplying the TSS concentration equivalent
to a turbidity value of 50 NTU (23 mg TSS/L) by the full range of measured flow values. Figure 12
presents the calculated loads based on the NCDENR monitoring data and the TMDL target loading. As
discussed in Section 2, the assimilative capacity of the East Fork is exceeded primarily during high-flow
events although the frequency of exceedance is fairly low.

East Fork Deep River Watershed TMDLs February 2004

19
TSS Load Duration Curve
1.0E-01
1.0E+00
1.0E+01
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
1.0E+07
0 10 20 30 40 50 60 70 80 90 100
Flow Duration Interval (%)
TS
S

(
l
b
/
d
a
y
)
TSS Load Limit Curve
Observed TSS Load

Figure 12. Load-Duration Curve for TSS

3.3.2 Determination of Existing Fecal Coliform Load and Assimilative
Capacity
The fecal coliform assessment also uses the Flow-Duration Curve approach for determination of the
existing load and assimilative capacity. The analysis was performed for both the instantaneous and
geometric mean standard to determine the most conservative measure of impairment. Figure 13 and
Figure 14 present the results of the instantaneous and geometric mean load-duration analyses based on
DENR and PTCOG data collected at Wendover Avenue. The average of the five flow observations
corresponding to the five fecal coliform sample dates was used as the flow for each geometric mean load.
As described in Section 3.2, many of the exceedances of the instantaneous standard occur during high-
flow events with occasional elevated levels during lower flows. This response is not seen as frequently
for the geometric mean analysis, supporting the conclusion that intermittent direct contributions are the
cause of the low-flow exceedances.
The load-duration curves developed in this section provide guidance in the determination of the pollutant
sources that are likely the primary contributors to elevated levels of fecal coliform. For example, elevated
fecal coliform levels that occur only during typical and high flow events are not likely to be caused by
failing septic systems. Nonpoint sources and sporadic sources such as sanitary sewer overflows would
likely be the main focus of the inventory in this case.
East Fork Deep River Watershed TMDLs February 2004

20
FC Instantaneous
Load Duration Curve
1.0E+09
1.0E+10
1.0E+11
1.0E+12
1.0E+13
1.0E+14
0 10 20 30 40 50 60 70 80 90 100
Flow Duration Interval (%)
FC

(
#
/
d
a
y
)
FC Inst Limit Curve
B 4240000
Wendover

Figure 13. Instantaneous Fecal Coliform Load-Duration Curves

FC Geomean
Load Duration Curve
1.0E+09
1.0E+10
1.0E+11
1.0E+12
1.0E+13
0 10 20 30 40 50 60 70 80 90 100
Flow Duration Interval (%)
FC

(
#
/
d
a
y
)
FC Geo Limit Curve
B 424000
Wendover

Figure 14. Geometric Mean Fecal Coliform Load-Duration Curves
East Fork Deep River Watershed TMDLs February 2004

21
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East Fork Deep River Watershed TMDLs February 2004

22
4 TMDL Development
Sections 1 through 3 described the processes and rationale required to identify the endpoints, critical
conditions, potential sources, and target loadings for each pollutant. These efforts formed the basis for
the TMDL process. This section describes the key components required by the TMDL guidelines and
synthesizes the project efforts to set the final TMDL allocations.
4.1 TMDL DEFINITION
A TMDL is the total amount of a pollutant that can be assimilated by the receiving water while still
achieving water quality criteria (in this case a target for warm water aquatic habitat). TMDLs can be
expressed in terms of mass per time or by other appropriate measures such as concentration. TMDLs are
comprised of the sum of individual wasteload allocations (WLAs) for point sources, load allocations
(LAs) for nonpoint sources, and natural background levels. In addition, the TMDL must include a margin
of safety (MOS), either implicitly or explicitly, that accounts for the uncertainty in the relationship
between pollutant loads and the quality of the receiving waterbody. Conceptually, this definition is
denoted by the equation:

TMDL = Σ WLAs + Σ LAs + MOS

4.2 TMDL ENDPOINTS
TMDL endpoints represent the instream water quality targets used in quantifying TMDLs and their
individual components. As discussed in Section 3, turbidity as a measure is not applicable to the
estimation of loading to a stream. TSS was selected as a surrogate measure for turbidity. Based on the
regression analysis, a TSS limit of 23 mg/L was determined to be equivalent to a turbidity measure of 50
NTU.
There are two endpoints that will be used to determine the fecal coliform TMDL, as specified in the North
Carolina water quality standards. Both the instantaneous limit of 400 cfu/100 mL and the geometric
mean of 200 cfu/100 mL were considered.
4.3 CRITICAL CONDITIONS
Based on the load-duration curves, the greatest frequency of exceedances for both turbidity and fecal
coliform occur during the summer period. Elevated turbidity occurs during high-flow events. Fecal
coliform impairment also occurs during high-flow events with occasional exceedances during typical
flows. The Load-Duration-Curve approach addresses the load reductions required during all flow
regimes. However, the majority of exceedances occurred during storm events, so these were the primary
targets for the load reductions.
4.4 SEASONAL VARIATIONS
Seasonal variation is considered in the development of the TMDLs because the allocation applies to all
seasons. As noted in the critical conditions section, the majority of the exceedances occur during the
summer months.
East Fork Deep River Watershed TMDLs February 2004

23
4.5 MARGIN OF SAFETY (MOS)
There are two methods for incorporating a MOS in the analysis: 1) by implicitly incorporating the MOS
using conservative model assumptions to develop allocations; or 2) by explicitly specifying a portion of
the TMDLs as the MOS and using the remainder for allocations. For the purposes of this analysis, an
explicit 10 percent margin of safety was specified.
4.6 TMDL CURVES
The load-duration curves presented in Section 3.3 provide the basis for the reductions required to meet the
TMDL targets. Allowable load curves were calculated with the water quality standards and a 10% MOS.
Based on guidance from EPA Region 4, data collected during extreme drought conditions (>95th
percentile) and floods (<10th percentile) were excluded from the reduction analysis. For the TSS and
fecal coliform geomean reductions, flow-duration and loading curves were generated from historical
monitoring data. These curves combine flow and observed concentrations to show the flow conditions
under which the water quality standards are exceeded. An existing loading curve could not be estimated
from the instantaneous fecal coliform data; therefore, the geometric mean of the exceedances was used as
an estimate of the existing load.
4.6.1 TMDL Curve for Turbidity
The results of the analysis described in Section 3 were used to develop flow-duration and loading curves
based on historical monitoring data. Exceedances of the estimated standard (23 mg TSS/L) were
identified within the 10th to 95th percentile flow recurrence range. The natural log of exceedances was
regressed on the natural log of the flow interval, and this regression curve was used to estimate the
existing loading at every 5th percentile flow recurrence. Allowable loading was calculated at every 5th
percentile flow recurrence based on the TMDL target value, which includes the 10 percent MOS. For the
estimates within the 10th to 95th percentile flow recurrence range, the average of the two sets of loading
estimates was calculated and the percent that the existing load exceeded the target was determined.
The target curve based on the TMDL limit and the MOS, and the regression curve based on exceedances
are shown in Figure 15. The average existing and target loadings were estimated at every fifth flow
interval. These results as well as the average values are presented in Appendix B. To meet the water
quality standard and account for the margin of safety, a 62 percent reduction is required.
East Fork Deep River Watershed TMDLs February 2004

24
TSS Load Duration Curve
1.0E-02
1.0E-01
1.0E+00
1.0E+01
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
1.0E+07
10 20 30 40 50 60 70 80 90
Flow Duration Interval (%)
TS
S

(
l
b
/
d
a
y
)
Observed TSS Load
Existing Load
TSS Load Limit w ith MOS
TSS = 8.1E+05 * Flow Interval -1.7

Figure 15. TMDL Curve Based on TSS Surrogate Standard for Turbidity
4.6.2 TMDL Curves for Fecal Coliform
The reductions for the instantaneous and geomean fecal coliform standard were estimated with the
observed data that exceeded the applicable water quality standard within the 10th to 95th percentile flow
recurrence range. For the instantaneous standard, a valid regression curve for existing loading could not
be estimated from the observed data. Therefore, the geomean of the exceedances was used as an estimate
of the existing load. The allowable loads for each exceedance were calculated based on the TMDL target
value, which includes the 10 percent MOS. The target curve based on the allowable loads and the
exceedances used for the existing load are shown in Figure 16. The geomeans of the exceedances and the
allowable loads were used to calculate the percent that the existing load exceeded the target.
The reductions for the fecal coliform geomean were estimated by regressing the natural log of
exceedances on the natural log of the flow interval. At every 5th percentile flow recurrence, the existing
loads were calculated from the regression equation, and the allowable loadings were calculated from the
TMDL target value, which includes the 10 percent MOS. The target curve based on the allowable
loadings, and the regression curve based on the exceedances are shown in Figure 17. Within the 10th to
95th percentile flow recurrence range, the average of the two sets of loading estimates was calculated and
the percent that the existing load exceeded the target was determined.
The loading estimates as well as the average values are presented in Appendix B. To meet the water
quality standard and account for the 10 percent margin of safety, a 75 percent reduction in fecal coliform
is required to meet the instantaneous limit (target load divided by existing load), and 63 percent reduction
is required to meet the geometric mean target.

East Fork Deep River Watershed TMDLs February 2004

25
FC Instantaneous
Load Duration Curve
1.0E+09
1.0E+10
1.0E+11
1.0E+12
1.0E+13
10 20 30 40 50 60 70 80 90
Flow Duration Interval (%)
FC

(
#
/
d
a
y
)
B4240000
Wendover
FC Load Limit w ith MOS

Figure 16. TMDL Curve Based on Instantaneous Fecal Coliform Standard, Exceedances Circled
FC Geomean
Load Duration Curve
1.0E+09
1.0E+10
1.0E+11
1.0E+12
10 20 30 40 50 60 70 80 90
Flow Duration Interval (%)
FC

(
#
/
d
a
y
)
B424000
Wendover
Existing Load Curve
FC Load Limit w ith MOS
FC = 10.0E+12 * Flow Interval -1.3

Figure 17. TMDL Curve Based on Geometric Mean Fecal Coliform Standard

East Fork Deep River Watershed TMDLs February 2004

26
4.7 TMDL SUMMARY
The load-duration curves for the existing and target conditions were evaluated to determine the reductions
needed to meet the TMDL endpoints. To achieve the specified TMDL targets, significant reductions
were required. These are summarized in Table 6.
Table 6. TMDL Reductions for TSS and Fecal Coliform
Pollutant Target Existing Load
(lb/day)
Target Load
(lb/day)
Reduction
Required
TSS <21 mg/L 2,564.6 973.3 62%
Fecal coliform
(Instantaneous Limit)
<360 cfu/100 mL 7.3x1011 1.8x1011 75%
Fecal coliform (Geometric
Mean Limit)
<180 cfu/100 mL 1.02x1011 3.8x1010 63%

The instantaneous standard is more restrictive than the geometric mean standard based on the percent
reduction required. The higher reduction requirement will be selected to provide an added margin of
safety to the TMDL.
The TSS and fecal coliform geometric mean reductions were used to develop the total TMDL loadings.
Further analysis was required to determine the breakdown between point source (WLA) and nonpoint
source (LA) loadings that meet the TMDL objectives. Based on the EPA guidance in regards to the Phase
II Rule, urban stormwater runoff from an MS4 is considered as a WLA component.
The entire East Fork Deep River watershed falls within the Phase II boundaries. Therefore, all TSS and
fecal loadings from urban landuses are assigned to the WLA component. Loadings from agricultural and
forested areas are considered as nonpoint sources and are reported as LAs. The distribution of the urban
and rural landuses, 12 percent and 88 percent respectively, was determined from the MRLC landuse
coverage discussed in Section 2. In addition, the relative loading rates between the urban and rural
landuse types was determined based on analysis of fecal coliform and TSS runoff data collected by USGS
and summarized in the report Relation of Land Use to Streamflow and Water Quality at Selected Sites in
the City of Charlotte and Mecklenburg County, North Carolina, 1993-98 (USGS, 1999). Water quality
data was collected at nine sites which drained relatively homogeneous landuses in order to estimate the
pollutant yields from each (See Appendix B). Average sediment and fecal coliform concentrations were
calculated by combining the estimates for the urban and rural watersheds. In addition, an estimate of SSO
and sewer break fecal coliform contributions was calculated based on available monitoring data and
literature values. The urban rate estimate for fecal coliform was increased to represent these non-runoff
associated contributions that were seen to be a significant source of the stream impairment in the East
Fork Deep River. The relative percent contributions of TSS and fecal coliform were combined with the
landuse distribution to estimate the overall relative loading ratios for urban (MS4) and rural (non MS4)
areas (Table 7). More information on these calculations is provided in the Appendix. It is important to
note that these estimates are based on data from the early 1990’s and are heavily weighted towards the
rural landuses.

East Fork Deep River Watershed TMDLs February 2004

27
Table 7. Relative Pollutant Contributions Rates
Pollutant Urban (% of Load) Rural (% of Load)
TSS 8 92
Fecal coliform 51 49

The assimilative capacity determined in Section 3.3 was split based on the relative contributions
presented in Table 7 to determine the WLA and LA components. The results of these calculations are
summarized in Table 8.
Table 8. East Fork Deep River TMDL Components
Pollutant Existing WLA LA MOS TMDL
TSS (lb/day) 2,564.6 77.9 895.4 Explicit 10% 973.3
Fecal coliform
(counts/day)
7.3x1011 9.2x1010 8.8x1010 Explicit 10% 1.8x1011

While these estimates help provide understanding of the relative loads, they are not definitive and should
be viewed in light of the limited data available to quantify the actual contributions from each individual
source. For example, the available land cover data is outdated and fails to represent current land use. The
primary focus of efforts to minimize future impairment should focus on the percent reductions required
and control of sources identified in the Source Assessment and discussed in the Implementation and
Future Efforts sections.
East Fork Deep River Watershed TMDLs February 2004

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5 Report Summary
This report presents the development of Total Maximum Daily Loads (TMDLs) for fecal coliform and
turbidity impairments of the East Fork Deep River. The East Fork of the Deep River near Greensboro,
North Carolina was placed on the North Carolina 2002 list of impaired waters (the 303(d) list) for
turbidity and fecal coliform. Available water quality data were reviewed to determine the frequency of
exceedances. The flow-duration curve method was applied to determine the critical periods and the
sources that lead to exceedances of the standard.
The potential sources determined from the load-duration curve were inventoried, and an assessment of
their relative contributions was used to allocate reductions among sources. Analysis of the turbidity and
total suspended solids monitoring data indicate that nonpoint sources, primarily development and
associated land disturbing activities, are the primary cause of the turbidity impairment. A review of fecal
coliform data indicates that storm event and intermittent point source contributions, such as sewer-pipe
breaks and SSOs, are the cause of the fecal coliform impairment. These results were used to derive the
allocations required by the TMDL.

East Fork Deep River Watershed TMDLs February 2004

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6 TMDL 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 in East Fork Deep River.
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.
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.
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7 Stream Monitoring
Monitoring will continue on a monthly interval at the ambient monitoring site in the East Fork Deep
River watershed. The continued monitoring of fecal coliform, turbidity, and total suspended solids will
allow for the evaluation of progress towards the goal of achieving water quality standards and intended
best uses.
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8 Future Efforts
MS4 jurisdictions within the East Fork watershed are Guilford County, the City of Greensboro, and the
City of High Point. Guilford County submitted its Phase II MS4 permit application in 2003. The county
has been operating an erosion control program since 1974, and its development ordinance requires that
construction sites use erosion and sediment-control BMPs. Guilford County began enforcing watershed
protection in 1984. According to its permit application and current development ordinance, the county
will continue to enforce the use of stormwater BMPs in water supply watersheds and improve the
monitoring of these BMPs (Guilford County, 2003).
The City of Greensboro submitted its Phase I MS4 permit application in 1994, renewed the Phase I permit
in 1999, and submitted its Phase II permit application in June 2003. The city requires erosion and
sediment controls and NPDES good-housekeeping measures at construction sites (City of Greensboro,
2003). All new high-density developments are required to treat stormwater runoff with wet detention
ponds, bioretention cells, stormwater wetlands, or sandfilters, following the state BMP guidelines. All
new low-density developments are required to treat stormwater runoff with land-disturbance buffers or
structural BMPs. The city has also conducted an educational campaign and recently completed an
inventory of all existing stormwater infrastructure (Small, 2003).
The City of High Point submitted its Phase II MS4 permit in March 2003. The city requires erosion
control plans for any land-disturbing activity greater than 1 acre (City of High Point, 2003). The city
began requiring stormwater controls in 1993 (Boone, 2003). The city requires a watershed development
plan for any lot greater than 20,000 square feet (City of High Point, 2003).
All three jurisdictions enforce state water-supply-watershed development regulations to High Point City
Lake. The majority of the East Fork drains the General Watershed Overlay District, while the
downstream portions of the watershed include High Point City Lake’s Watershed Critical Area.
Fecal coliform impairments appear to be driven mostly by storm events. The contributions during these
events may include runoff from agricultural areas, urban stormwater washoff, and SSO events.
Additional impairments occurred more infrequently during lower flow events and are most likely caused
by sewer blockages or leaks. Review of the PTCOG study (2003) provides significant insight into
specific areas within the watershed which appear to warrant further investigation.
Other potential mechanisms for reduction of both pollutants include local regulations or ordinances
related to zoning, landuse, or storm water runoff controls. Local governments can provide funding
assistance through general revenues, bond issuance, special taxes, utility fees, and impact fees.
Additional mechanisms may employ concurrent education and outreach, training, technology transfer, and
technical assistance with incentive-based pollutant management measures. The State and local
governments will take the primary lead in the TMDL implementation.
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9 Public Participation
A draft of the TMDL was publicly noticed through various means, including notification in the local
newspapers, Greensboro News and Record and High Point Enterprise on December 10, 2003. DWQ
electronically distributed the draft TMDL and public comment information to known interested parties.
The TMDL was also available from the Division of Water Quality’s website at
http://h2o.enr.state.nc.us/tmdl/ during the comment period. A public meeting was held on December 19,
2003 to present the TMDL and answer questions. In addition to DWQ staff, 4 people attended. The
public comment period ended on January 13, 2004. No comments were received.

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10 Further Information
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/
Technical questions regarding this TMDL should be directed to the following members of the DWQ
Modeling/TMDL Unit:
J. Todd Kennedy, Modeler and Project Manager
e-mail: [e-mail]
Michelle Woolfolk, Supervisor
e-mail: [e-mail]

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11 References
Boone, Derrick. 2003. City of Greensboro, North Carolina (personal communication).
City of Greensboro. 2003. The City of Greensboro Stormwater Management Program Report.
Municipal NPDES Stormwater Permit Renewal Application.
City of High Point. 2003. City of High Point Stormwater Management Program Report.
Cleland, B.R. 2002. TMDL Development from the “Bottom Up” – Part II: Using Load Duration Curves
to Connect the Pieces. Proceedings from the WEF National TMDL Science and Policy 2002 Conference.
Cook, Ken. 2003. City of Greensboro, North Carolina (personal communication).
Guilford County. 1995. Forecast 2015: Guilford County Atlas. Guilford County, North Carolina.
Guilford County. 2003. Comprehensive Stormwater Management Program.
http://www.co.guilford.nc.us/government/planning1/wshome.html
Hepler, Bart. 2003. City of High Point, North Carolina (personal communication).
Patrick, Carol. 2003. Identification and Reduction of Fecal Coliform Bacteria Sources for North
Carolina 303(d) Listed Waters in Greensboro and High Point. Piedmont Triad Council of Governments.
Peacock, Jerry. 2003. City of Greensboro, North Carolina (personal communication).
Pegram, Charles. 2003. City of Greensboro, North Carolina (personal communication).
Phlegar, David. 2003. City of Greensboro, North Carolina (personal communication).
Small, Tori. 2003. City of Greensboro, North Carolina (personal communication).
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. 1990. 1990 Census of Population and Housing.
http://govinfo.library.orst.edu/index.html (April, 2002).
U.S. Census Bureau. 2000. Census 2000 Summary File. http://factfinder.census.gov
USDA 2002. United States Department of Agriculture. Census Data. http://www.nass.usda.gov/census/
USEPA. 1991. Guidance for Water Quality-Based Decisions: The TMDL Process. Environmental
Protection Agency, Assessment and Watershed Protection Division, Washington D.C.
USEPA. 1998. Draft final TMDL Federal Advisory Committee Report. U.S. Environmental Protection
Agency, Federal Advisory Committee (FACA), Washington D.C. 4/28/98.
USEPA. 1999. Protocol for Developing Sediment TMDLs. 1st Edition. EPA 841-B-99-004. U.S.
Environmental Protection Agency, Office of Water, Washington D.C.
USEPA. 2000. 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. U.S. Environmental Protection Agency,
Washington D.C. Fed. Reg. 65:43586-43670 (July 13, 2000).
USEPA. 2001. Protocol for Developing Pathogen TMDLs. 1st Edition. EPA 841-R-00-002. U.S.
Environmental Protection Agency, Office of Water, Washington D.C.
East Fork Deep River Watershed TMDLs February 2004

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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.
USGS. 2001. Water Resources of the United States. NWIS-web online hydrologic data:
http://water.usgs.gov (April, 2002).
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12 Appendices
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Appendix A Water Quality Sampling Data
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Table 9. NCDENR Monitoring Data for Station B4240000 near Wendover Ave. (1997-2002)
Date Flow (cfs) Flow Regime Turbidity (NTU) TSS (mg/L)
Fecal Coliform
(#/100mL)
10/23/1997 9.0 37.5 12 4 10
11/19/1997 8.8 38.3 15 5 120
12/17/1997 7.7 45.3 9.3 5 10
1/26/1998 13.0 23.8 40 9 140
2/23/1998 47.0 5.6 80 150 490
3/16/1998 9.2 36.2 19 8 45
4/22/1998 11.0 29.9 70 48 250
5/20/1998 8.2 42.1 13 7 110
6/17/1998 8.3 41.6 32 16 130
7/16/1998 19.0 14.5 6 5 27
8/18/1998 5.9 61.6 32 17 260
9/9/1998 9.1 36.6 50 22 1100
10/7/1998 3.6 90.2 10 7 230
11/5/1998 2.8 97.0 5 1 60
12/15/1998 6.7 53.7 49 26 210
1/19/1999 18.0 15.7 18 20 120
3/17/1999 8.1 42.6 23 8 10
5/26/1999 5.9 61.6 10 3 10
6/15/1999 6.9 51.8 24 22 4100
7/27/1999 3.7 88.5 7 1 64
8/31/1999 8.0 43.3 40 3 70
9/30/1999 89.0 3.1 140 100 5000
10/28/1999 6.5 55.7 16 3 70
11/23/1999 5.8 62.7 5 1
12/28/1999 5.8 62.7 19 7 120
2/23/2000 8.7 38.8 30 6 18
3/30/2000 8.4 40.5 24 7 120
4/26/2000 9.1 36.6 19 5 90
5/30/2000 8.3 41.6 14 8
6/28/2000 14.0 21.7 16 2 54
East Fork Deep River Watershed TMDLs February 2004

48
Date Flow (cfs) Flow Regime Turbidity (NTU) TSS (mg/L)
Fecal Coliform
(#/100mL)
7/27/2000 7.0 51.2 26 990
8/16/2000 3.8 87.6 17 110
9/26/2000 58.0 4.6 120 3700
10/30/2000 5.7 64.0 14 63
11/29/2000 9.4 35.0 23 210
12/21/2000 9.4 35.0 3.7 200
1/16/2001 5.5 66.0 9.2 120
4/3/2001 39.0 6.8 60 210
5/22/2001 6.8 53.1 8.3 5 73
6/25/2001 8.5 940
7/17/2001 4.8 74.1 7.4 88
8/23/2001 3.5 91.0 5 5
9/17/2001 5.5 66.0 6.3 200
10/4/2001 4.7 75.4 4.3 53
11/20/2001 3.7 88.5 8 4
12/20/2001 6.0 60.8 25
1/17/2002 3.6 90.2 6.2 130
2/13/2002 6.9 51.8 20 6 100
3/26/2002 21.0 12.9 17 34
4/25/2002 5.1 70.3 45
5/20/2002 3.3 93.0 16 4
6/24/2002 1.1 100.0 12 19
7/15/2002 9.5 34.6 17 18
8/8/2002 0.6 100.0 13 6 120
9/18/2002 34.0 7.7 25 9.3
Note: Does not include turbidity or fecal coliform data on dates where gage data was unavailable.

East Fork Deep River Watershed TMDLs February 2004

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Table 10. PTCOG Fecal Coliform Monitoring Data 2001-2003
Date
Flow (cfs)
(USGS020
99000)
Flow
Regime
Previous
Rainfall
(Hours)
Thatcher
Rd.
Albert
Pick Rd.
Gallimore
Dairy Rd.
Piedmont
Parkway
Wendover
Ave.
4/9/2001 11 30.4% 144 14 70 58 43 51
4/11/2001 10 33.0% 192 26 143 35 130 80
4/23/2001 7.8 45.1% 120 27 277 160 42 25
4/24/2001 12 27.0% 144 22 130 185 104 204
5/3/2001 5.7 64.3% 360 62 106 130 54 30
5/4/2001 5.4 67.3% 384 105 790 112 120
5/8/2001 4.8 74.4% 480 105 347 56 92 168
5/9/2001 5.1 70.6% 504 350 523 88 58 227
6/6/2001 81 3.4% 72 120 200 270 270 68
6/12/2001 4.5 78.6% 72 148 197 460 260 102
6/18/2001 5.3 68.6% 72 930 240 440 196 110
6/21/2001 4 85.2% 144 380 320 1200 152 108
7/17/2001 4.8 74.4% 72 88 228 12320 137 142
8/20/2001 5.1 70.6% 370 460 203
8/23/2001 3.5 91.0% 980 228
8/27/2001 5.4 67.3% 4600 134
9/12/2001 8.7 39.2% 620 350
9/17/2001 5.5 66.3% 540 218
10/30/2001 4 85.2% 239 176 6
11/1/2001 3.8 87.8%
11/28/2001 4.3 81.1% 96 226 140 92 120 45
1/9/2002 7.7 45.7% 115 272 264
1/14/2002 4 85.2%
3/5/2002 8.2 42.6% 48 38 44 48 104 182
5/8/2002 3.5 91.0% 24 248 220 160 104
5/29/2002 1.8 99.5% 96
6/3/2002 5.5 66.3% 48 310 1100 1260 550 287
6/6/2002 7.7 45.7% 72
7/9/2002 2.5 98.3% 36 1200 380 700 185 130
7/15/2002 9.5 35.1% 72 580 876
East Fork Deep River Watershed TMDLs February 2004

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Date
Flow (cfs)
(USGS020
99000)
Flow
Regime
Previous
Rainfall
(Hours)
Thatcher
Rd.
Albert
Pick Rd.
Gallimore
Dairy Rd.
Piedmont
Parkway
Wendover
Ave.
10/24/2002 8.3 42.1% 72 100 171 280 230 210
10/28/2002 49 5.5% 48 2000 4900 8700 4600 3100
10/29/2002 86 3.2% 24 5900 6000 12000 5400 13800
10/31/2002 24 11.5% 24 600 800 5000 2200 1200
11/4/2002 8.7 39.2% 48 44 440 340 150 81
11/5/2002 37 7.2% 72 56 360 425 188 152
11/7/2002 21 13.2% 24 250 400 365 480 773
11/14/2002 21 13.2% 36 220 400 230 510 430
11/18/2002 38 7.1% 24 118 210 390 250 250
11/19/2002 21 13.2% 36 68 260 138 260 220
11/21/2002 13 24.3% 48 31 370
11/26/2002 7.1 50.9% 96 33 1180
12/3/2002 7 51.6% 24 240 480
12/12/2002 38 7.1% 48 162 510
12/18/2002 8 43.7% 24 270 400
1/6/2003 13 24.3% 24 10 204
1/7/2003 10 33.0% 48 88 210
1/13/2003 6.8 53.5% 144 128 200
1/16/2003 6.4 56.8% 92

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Appendix B Load Reduction Calculations
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Table 11. Estimation of Load Reduction for Turbidity (lb/day TSS)
Flow
Interval Target Load Existing Load
10 2,903.1 16,366.6
15 2,009.8 8,171.3
20 1,563.2 4,991.8
25 1,339.9 3,405.9
30 1,228.2 2,492.2
35 1,060.7 1,913.8
40 960.2 1,522.5
45 870.9 1,244.3
50 792.8 1,038.8
55 736.9 882.3
60 669.9 760.1
65 625.3 662.7
70 569.4 583.7
75 524.8 518.6
80 480.1 464.4
85 446.6 418.5
90 402.0 379.5
95 335.0 345.9
Average 973.3 2,564.6

East Fork Deep River Watershed TMDLs February 2004

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Table 12. Estimation of Load Reduction (#/day) based on Fecal Coliform Instantaneous Standard
Flow
Interval Target Load Existing Load
12.6 2.2E+12 1.9E+11
17.1 1.5E+12 1.5E+11
11.5 7.0E+11 2.1E+11
13.2 4.0E+11 1.8E+11
13.2 2.2E+11 1.8E+11
Geomean 1.8E+11 7.3E+11

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Table 13. Estimation of Load Reduction (#/day) based on Fecal Coliform Geometric Mean
Standard
Flow
Interval Target Load Existing Load
10 1.1E+11 4.8E+11
15 7.9E+10 2.8E+11
20 6.2E+10 1.9E+11
25 5.3E+10 1.5E+11
30 4.8E+10 1.1E+11
35 4.2E+10 9.3E+10
40 3.8E+10 7.8E+10
45 3.4E+10 6.7E+10
50 3.1E+10 5.8E+10
55 2.9E+10 5.2E+10
60 2.6E+10 4.6E+10
65 2.5E+10 4.1E+10
70 2.2E+10 3.8E+10
75 2.1E+10 3.4E+10
80 1.9E+10 3.1E+10
85 1.8E+10 2.9E+10
90 1.6E+10 2.7E+10
95 1.3E+10 2.5E+10
Average 3.8E+10 1.02E+11

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Table 14. Estimates of TSS and Fecal Coliform Runoff Loading Rates for Urban and Rural Lands
(USGS, 1999)
Landuse Type TSS Conc.
(ton/mi2/yr)
FC Conc.
(mg/L)1
Mixed forest/pasture/ low density
residential
2400 15
Mixed forest, pasture, medium-
and low-density residential
2100 20
Mixed forest, pasture, medium-
and low-density residential
564 24.5
Average Rural 1688.0 19.8
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
Average Urban 1070.7 20.9
1 Loading estimates not developed by USGS for coliform

Table 15. Estimates of Direct Fecal Coliform Contribution from Urban Sources
Typical SSO and Sewer Effluent
Concentration (#/100mL)
Estimated Percent of
Storm Event
Contribution
Additional Contribution to Urban
Fecal Loading Rate (#/100mL)
10,0001 0.6752 67.5
1 Source: (EPA, 2001)
2 Based on reported SSO overflows

Table 16. Relative Urban and Rural TSS Areal Loading
Landuse Landuse Distribution Relative TSS Rate TSS Loading Ratio
Rural 87.8% 1688 92.0%
Urban 12.2% 1070 8.0%
Notes:
1-TSS data collected at nine urban and rural sites were analyzed to estimate average sediment
concentrations in stormwater runoff. The relative percent contributions of TSS were multiplied by the
landuse distribution and normalized to estimate the relative loading ratio for urban (MS4) and rural
(non MS4) areas.
2-Land use data is from the early 1990’s and may not represent current conditions.

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Table 17. Relative Urban and Rural FC Areal Loading
Landuse Landuse Distribution Relative FC Rate FC Loading Ratio
Rural 87.8% 19.8 48.9%
Urban 12.2% 88.4 51.1%
Notes:
1-Fecal coliform data collected at nine urban and rural sites were analyzed to estimate average fecal
coliform concentrations in stormwater runoff. The urban rate estimate was increased based on
available SSO and sewer break monitoring and literature to represent the non-runoff associated
contributions (20.9 plus 67.5). The relative percent contributions of fecal coliform were multiplied by
the landuse distribution and normalized to estimate the relative loading ratio for urban (MS4) and rural
(non MS4) areas.
2- Land use data is from the early 1990’s and may not represent current conditions.

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Appendix C Affidavits of Publication for Public Notice
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