HomeMy WebLinkAboutGrants TMDL finalFinal Total Maximum Daily Load (TMDL)
for Fecal Coliform
August 2002
(Approved September, 2002)
Grants Creek (Subbasin 03-07-04)
Yadkin-Pee Dee River Basin
North Carolina
Prepared by:
NC Department of Environment and Natural Resources
Division of Water Quality
Water Quality Section
1617 Mail Service Center
Raleigh, NC 27699-1617
(919) 733-5083
Final Fecal Coliform TMDL for Grants Creek
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INDEX OF TMDL SUBMITTAL
303(d) List Information
State North Carolina
Basin Yadkin-Pee Dee River Basin
303(d) Listed Waters
Name of Stream Description Class Index #8 Digit CU Miles
Grants Creek From source to Yadkin River C 12-110 03040103 17.9
8 Digit Cataloging Unit(s) 03040103
Area of Impairment 17.9 miles
WQS Violated Fecal Coliform
Pollutant of Concern Fecal Coliform
Sources of Impairment Point and nonpoint sources from entire
watershed
Public Notice Information
Form of Public Notification: A draft of the Grants Creek Fecal Coliform TMDL was publicly noticed
through various means, including notification in a local newspaper and published Cooperative Extension
Newsletter. The TMDL was also available from the Division of Water Quality’s website
(http://h2o.enr.state.nc.us/tmdl/draft_TMDLS.htm) during the comment period. A public comment period
was held for the 30 days prior to May 24, 2002. A public meeting was held in Salisbury on May 8, 2002.
Did notification contain specific mention of TMDL proposal? Yes
Were comments received from the public? Yes
Was a responsiveness summary prepared? A summary of the comments and DWQ’s responses
are included in Appendix VII of the TMDL document
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TMDL Information
Critical condition wet weather, spring
Seasonality Modeled from 1995 - May 2001 to include fluctuations in seasonal
fecal coliform loading.
Development tools Coliform Routing and Allocation Program (CRAP)
Supporting documents “Final Total Maximum Daily Load for Fecal Coliform, Grants
Creek”
TMDL(s)
Loading allowed at critical condition:
Wasteload Allocation (WLA): 1.75 x 1011 cfu per 30 days
Load Allocation (LA): 2.18 x 1013 cfu per 30 days
Total Maximum Daily
Load (TMDL)
Sources Sub-
Watershed
Wet
Weather
Fecal
Coliform
Loading
Reductions
Dry Weather
Fecal
Coliform
Loading
Reductions
Wasteload
Allocation (WLA) WWTP WS02-WS3 0% 0%
High Density Development WS01-WS03 94% 33%
Low Density Development WS01-WS03 94% 33%
WS01-WS02 97% 60%Livestock Grazing/Manure
Application (Pastureland)
WS3 85% 40%
Load Allocation (LA)
Manure Application (Cultivated) WS01-WS02 97% 60%
Wildlife WS01-WS03 0% 0%
Margin of Safety Explicit margin of safety of 25 cfu/100ml.
Final Fecal Coliform TMDL for Grants Creek
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TABLE OF CONTENTS
1.0 INTRODUCTION………………………………………………………………. 1
1.1 Watershed Description………………………………………………….. 3
1.2 Water Quality Monitoring Program…………………………………….. 5
1.3 Water Quality Target……………………………………………………. 9
2.0 SOURCE ASSESSMENT………………………………………………………. 10
2.1 Point Source Assessment……………………………………………….. 10
2.2 Non-point Source Assessment…………………………………………. 11
3.0 MODELING APPROACH………………………………………………………14
3.1 Model Framework………………………………………………………. 14
3.2 Model Setup…………………………………………………………….. 14
3.3 Fecal Coliform Source Representation…………………………………. 17
3.4 Instream Decay Rate……………………………………………………. 23
3.5 Uncertainty ………...…………………………………………………... 24
3.6 Critical Conditions………………………………………………………25
3.7 Model Results…………………………………………………………... 25
4.0 ALLOCATION………………………………………………………………….. 28
4.1 Total Maximum Daily Load (TMDL)…………………………………... 28
4.2 Seasonal Variations …………………………………………………….. 28
4.3 Margin of Safety ……………………………………………………. 28
4.4 Load Reduction ………………………………………………………. 29
5.0 SUMMARY AND FUTURE CONSIDERATIONS ……………………………32
5.1 Monitoring………………………………………………………………. 32
5.2 Implementation………………………………………………………….. 33
6.0 PUBLIC PARTICIPATION……………………………………………………33
7.0 REFERENCES …………………………………………………………………. 34
APPENDIX I Grants Creek Fecal Coliform Ambient Monitoring Data
APPENDIX II Grants Creek DWQ Special Study Monitoring Data
APPENDIX III Yadkin Pee-Dee River Basin Association Discharger Coalition Data
APPENDIX IV Spencer WWTP Upstream/ Downstream Monitoring Data
APPENDIX V Grants Creek WWTP Upstream/ Downstream Monitoring Data
APPENDIX VI Public Notification of Public Review Draft of Grants Creek Fecal
Coliform TMDL.
Appendix VII. Public Comments and Responsiveness Summary to Public Review Draft of
Grants Creek Fecal Coliform TMDL
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1.0 INTRODUCTION
The North Carolina Division of Water Quality (DWQ) has identified a 17.9 mile segment (12-
110-20) of Grants Creek in the Yadkin River Basin as impaired by fecal coliform bacteria as
reported in the 2000 North Carolina 303(d) list. The creek is impaired from its source near the
Town of Landis to its confluence with theYadkin River. This section of the stream is located in
subbasin 03-07-04 and is designated as a class C water.1
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.
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, 2000a) and the Federal Advisory Committee (FACA, 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 or 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.
1 Class C waters are freshwaters that are protected for secondary recreation, fishing, aquatic life including
propagation and survival of wildlife.
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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 (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).
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, 2000a) require EPA to review all TMDLs for approval or disapproval. Once EPA
approves a TMDL, then the waterbody may be moved to Part III of the 303(d) list. Waterbodies
remain on Part III 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 still
result in the restoration of water quality.
The goal of the TMDL program is to restore designated uses to water bodies. Thus, the
implementation of bacteria controls will be necessary to restore uses in Grants Creek. Although
an implementation plan is not included as part of this TMDL, reduction strategies are needed.
The involvement of local governments and agencies will be critical in order to develop
implementation plans and reduction strategies. DWQ will begin developing the implementation
plan during public review of the TMDL.
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1.1 Watershed Description
Grants Creek, located in the Yadkin-Pee Dee River Basin, drains into the Yadkin River. Figure
1 depicts the location of Grants Creek in North Carolina. The creek originates near the Town of
Landis, and continues flowing for 17.9 miles through China Grove, Salisbury and Spencer to the
Yadkin River. The Grants Creek watershed in the TMDL includes the drainage area above the
confluence of Grants Creek and Yadkin River. The creek’s watershed lies entirely within the
High Rock Lake and Muddy Creek Watersheds (Subbasin # 03-07-04) in Rowan County. The
USGS 14-digit hydraulic unit code (HUC) for Grants Creek is 03040103010010. The Grants
Creek watershed comprises a total area of approximately 43,227 acres or 67.5 square miles. The
creek flows near numerous industrial sites and multiple municipalities including Landis, China
Grove, Rowan Mills, Salisbury, and Spencer. DWQ has an ambient water quality monitoring
station near Spencer.
The land use/ land cover characteristics of the watershed were determined using 1996 land cover
data. The North Carolina Center for Geographic Information and Analysis (NCCGIA), in
cooperation with the NC Department of Transportation and USEPA Region IV Wetlands
Division, contracted Earth Satellite Corporation (EarthSat) of Rockville, Maryland to generate
comprehensive land cover data for the entire state of North Carolina. The majority of the Grants
Creek Watershed is in upland hardwood forest. Pasture and uncultivated agricultural fields
comprise the second largest land use group. Cultivated fields comprise the third largest land use.
Developed areas are split into high and low intensity groups. The difference between these
developed groups depends upon the concentration of impervious surfaces in an area mapped. The
Grants Creek Watershed is considered a rural watershed, which means that approximately 10%
of the watershed is covered with impervious surfaces (Schueler 1994). Land cover/land use
coverage for the Grants Creek watershed is shown in Table 1.
Table 1. Estimated Land Use/Land Cover in the Grants Creek Watershed
Land Use/Land Cover Description % Of Watershed Acres
Forested Mostly Upland Hardwoods 57 24,639.39
Managed Herbaceous Cover Pasture/Uncultivated Fields 23 9,942.21
Cultivated Lands Crop lands 10 4,322.70
High Intensity Development Over 80% Impervious Material 5 2,161.35
Low Intensity Development 50-80% Impervious 5 2,161.35
Total: 100 43,227.00
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Final Fecal Coliform TMDL for Grants Creek
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1.2 Water Quality Monitoring Program
Water quality data available from Grants Creek monitoring stations show high levels of fecal
coliform bacteria in the creek. Water quality data from fecal coliform monitoring of Grants
Creek comes from five primary sources. Figure 2 shows the locations of the monitoring stations
in the Grants Creek watershed.
Data from DWQ’s ambient monitoring station at Spencer (Q4600000 - Grants Creek below
Salisbury and Spencer WWTP) were used to determine the impaired status of the creek. The
fecal coliform samples were collected on a monthly interval beginning in April 1995 to the
present. The fecal coliform concentrations of the samples collected at the DWQ ambient
monitoring station ranged from 10cfu/100ml to 17,000 colony-forming-units (cfu)/100ml
(Figure 3). The fecal coliform concentrations of the samples collected by the discharger coalition
at stations Q4540000 and Q4600000 ranged from 1 cfu/100ml to 4,900 cfu/100ml, and 18
cfu/100ml to 6000 cfu/100mL, respectively, between July 1998 and April 2001 (Appendix III).
Samples are collected at the DWQ ambient monitoring station and at the discharger coalition
stations on a monthly basis. As a result, the 30-day geometric mean of the samples could not be
calculated using the minimum required 5 samples in 30 days.
The Grants Creek and Spencer WWTPs monitored instream fecal coliform concentrations at
upstream and downstream locations in years prior to the discharger coalition monitoring. The
upstream/downstream fecal coliform concentration data are shown in figures 4 and 5, and
Appendix IV and V.
Yadkin-Pee Dee River Basin Association discharger coalition (YRBA) has been monitoring
fecal coliform levels at third street extension near Spencer, and below Salisbury and Spencer
WWTPs since 1998. Data collected at discharger coalition stations are shown in Appendix III.
The Rowan County Environmental Services has conducted fecal coliform monitoring at three
stations in the creek in 2000 and 2001 in support of Grants Creek Watershed Management
Planning study funded by the Clean Water Management Trust Fund (CWMTF). Figure 6 shows
the fecal coliform monitoring data from this study.
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Finally, the most recent fecal coliform monitoring data come from a special study conducted by
DWQ’s Environmental Sciences Branch (ESB) in the spring of 2001 to support the TMDL
development. In this study, 10 samples were collected from three sites over a six and one-half
week period. The samples were collected at the ambient monitoring site, at the YRBA coalition
site, and downstream of the Grants Creek WWTP. The purposes of this study were to evaluate
whether the creek was complying with state fecal coliform standard, and to provide information
on potential bacteria sources in the watershed. The data summary from this study is given in
Table 2.
Figure 2. Grants Creek Fecal Coliform Bacteria Monitoring Location
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Figure 4. Grants Creek WWTP Upstream / Downstream 30-day Rolling Geometric Mean of
Fecal Coliform Concentration (NC0023884)
1
10
100
1000
10000
1/3/1997 3/3/1997 5/3/1997 7/3/1997 9/3/1997 11/3/1997 1/3/1998 3/3/1998 5/3/1998
Date
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upstream WQ Standard downstream #2 downstream #1
Figure 3. Grants Creek Fecal Coliform Levels at Spencer
(DWQ Ambient Monitoring data)
1
10
100
1000
10000
100000
5/23/1995 5/23/1996 5/23/1997 5/23/1998 5/23/1999 5/23/2000
Date
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fecal coliform
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Figure 5. Grants Creek Spencer WWTP Upstream / Downstream 30-day Rolling Geometric
Mean of Fecal Coliform Concentration (NC0025593)
1
10
100
1000
10000
1/3/1997 3/3/1997 5/3/1997 7/3/1997 9/3/1997 11/3/1997 1/3/1998 3/3/1998 5/3/1998
Date
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downstream upstream WQ Standard
Figure 6. Rown County Environmental Services Grants Creek Fecal Coliform Monitoring
data (Geometric Mean)
1
10
100
1000
10000
4/6/2000 7/6/2000 10/6/2000 1/6/2001 4/6/2001 7/6/2001
Date
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Rowan Mill Rd.Old Wilksboro Rd.Third St.Standard
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Table 2. Summary of Grants Creek Fecal Coliform Data from DWQ Special Study2
Fecal Coliform Levels
(Geometric Mean)
Dates Number of
days
Observations Downstream of
Spencer WWTP
Outfall
Rowan Co. at
70-601
Rowan Co. at
SR 1505
4/11/2001 to 5/9/2001 29 15 284 469 662
4/18/2001 to 5/16/2001 29 15 338 473 852
4/25/2001 to 5/23/2001 29 15 678 758 1187
5/2/2001 to 5/30/2001 29 15 528 474 855
2 The complete data from the study is given in Appendix II
2.1 Water Quality Target
The North Carolina fresh water quality standard for Class 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
400/100 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 non-point 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 instream numeric target, or endpoint, is the restoration objective expected to be reached by
implementing the specified load reductions in the TMDL. The target allows for the evaluation of
progress towards the goal of reaching water quality standards for the impaired stream by
comparing the instream data to the target. For Grants Creek fecal coliform TMDL, the water
quality target is the geometric mean concentration of 200cfu/100ml over a 30-day period. The
TMDL also addresses the portion of the standard that limits the percentage of instantaneous
excursions over 400cfu/100ml to twenty percent.
Final Fecal Coliform TMDL for Grants Creek
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In order to evaluate the fecal coliform model, monitor water quality conditions and assess
progress of the TMDL, an evaluation location was established for the Grants Creek watershed.
The evaluation location of this watershed is located in Grants Creek downstream of the Grants
Creek WWTP, which is the location of the ambient monitoring stations.
2.0 SOURCE ASSESSMENT
A source assessment is used to identify and characterize the known and suspected sources of
fecal coliform bacteria in the watershed. The source assessment of Grants Creek will be used in
the water quality model and in the development of the TMDL.
2.1 Point Source Assessment
General sources of fecal coliform bacteria are divided between point and non-point sources.
Facilities that treat domestic waste which are permitted through the National Pollutant Discharge
Elimination System (NPDES) are the primary point sources of fecal coliform bacteria.
2.1.1 Individually Permitted NPDES Dischargers
There are six NPDES permitted dischargers in the Grants Creek watershed. Table 3 shows
individually permitted NPDES wastewater treatment facilities in the watershed. The City of
Salisbury Grants Creek WWTP previously discharged to Grants Creek (until September 2000),
but now discharges to the Yadkin River. This WWTP primarily serves, the northern side of
Salisbury, and the towns of Landis and China Grove. The Town of Spencer WWTP
(NC0025593), now called Sowers Ferry WWTP, directly discharges into Grants Creek. The
Spencer WWTP operates at 0.75 MGD, and has a maximum permitted effluent fecal coliform
concentration of a 30-day geometric mean of 200 cfu/100ml, and a weekly geometric mean of
400 cfu/100ml. The Grants Creek WWTP land applies a percentage of the residuals generated
during the wastewater treatment process. A percentage of the residuals is land applied within the
Grants Creek watershed (Helms Communication, 2002). The other four facilities are minor
discharges and their contribution to the fecal coliform loading is not significant.
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2.1.2 General Permitted NPDES Dischargers
There is one general permitted facility located in the Grants Creek watershed. This facility is
permitted to discharge non-contact cooling water, boiler blowdown, cooling tower blowdown,
and other similar wastewaters. The effluent of this facility is not limited or monitored for fecal
coliform.
Table 3. Permitted NPDES wastewater treatment facilities in Grants Creek Watershed.
Facility Name
Permitted
Flow
(MGD)
Site Address Site City
Receiving
Stream Permit #Ownership
Fieldcrest Cannon-
Plant 16 0.05
5200 South Main
Street Salisbury
UT Grants
Ck. NC0004286Non-Municipal
Spencer, Town –
WWTP 0.75
600 Sower Ferry
Road Spencer Grants Ck. NC0025593Municipal
Landis, Town –
WTP
255 Tranquil Lake
Drive Chaina GroveGrants Ck. NC0027502Non-Municipal
Oak Haven Mobile
Home Park 0.006 775 Airport Road Salisbury
UT Grants
Ck.NC0037184 Non-Municipal
Westside Swim &
Raquet Club 0.003 Salisbury Draft Branch NC0042439Non-Municipal
Majestic Properties-
Rowan Site 0.005
2001 South Main
Street Salisbury
UT Grants
Ck.Minor Non-Municipal
Rowan-Salisbury
Sch/ Knollwood 0.011 Salisbury Little Creek NC0034703Non-Municipal
Inman Asphalt –
Salisbury
1825 Jake
Alexander Blvd.
West Salisbury
UT Grants
Ck. NC0049905Non-Municipal
2.2 Non-point Source Assessment
Non-point sources of fecal coliform bacteria include those sources that can not be identified as
entering the waterbody at a specific location (e.g., a pipe). Non-point source pollution can
include both urban and agricultural sources. Fecal coliform bacteria may originate from human
and non-human sources. Table 4 lists the potential human and animal non-point sources of fecal
coliform bacteria (Center for Watershed Protection, 1999). The non-point sources of fecal
coliform bacteria in Grants Creek include wildlife, livestock (land application of agricultural
manure and grazing), concentrated animal feed-lots, urban development (stormwater), failing
septic systems, and sewer line systems (illicit connections, leaky sewer lines and sewer system
overflows).
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Table 4. Potential sources of fecal coliform bacteria in urban and rural watersheds (Center for
Watershed Protection, 1999).
Source 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 Livestock
Rowan County, with a total area of 327,296 acres is a producer of cattle, beef and milk cows,
chickens, hogs and pigs. According to the 1997 Agricultural Census, there were 48 poultry
farms, 473 beef farms and 36 dairy farms in Rowan County. There is one certified dairy cattle
farm, and one beef cattle farm (150 head) in the Rowan County portion of Grants Creek. There
are no permitted concentrated animal feedlot operations (CAFOs) in the watershed. There are
also several small livestock farms scattered throughout the watershed (Cowden communications,
2002). In 1997 there were 154 horse and pony farms throughout Rowan County (Agriculture
Census, 2001).
2.2.1.1 Livestock Grazing/Horse and Pony Grazing
Cattle, including both dairy and beef cows, and horses graze on pasture land and deposit feces
onto the land. During a rainfall runoff event, a portion of the fecal material that contains
coliform bacteria is transported to the streams. In addition, when cattle have direct access to
streams, feces may be deposited directly into a stream. There are small, scattered animal
operations which may have access to streams for their animals in the Grants Creek Watershed.
(Cowden communication, 2001).
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2.2.1.2 Agricultural Manure Application/Concentrated Animal Feedlot Operations
The registered dairy cattle operations in Rowan County have onsite lagoons. The average cattle
population of the registered dairy operation in the Grants Creek watershed is 175 head of cattle.
There are about 340 dairy cattle in the farm currently. The estimated number of cattle in the beef
cattle operation is about 150. Overall, it is estimated that there are about 2500 head of dairy and
beef cattle in the Grants Creek area (Rider communications, 2002). The cattle may have limited
access to streams. Dairy manure is mostly applied to cropland with some to pasture /hayland.
Manure is generally applied to cropland from March to June and from September to November.
Manure is typically applied to pastureland during the same periods, although application extends
through December. Poultry litter produced by the chickens is routinely collected and applied as
an alternative to fertilizer and applied predominately to pasture/hayland (Rowan SWCD
communications, 2002). The City of Salisbury is permitted to land apply residuals from its
wastewater treatment process. The applications fields are scattered in the south and southwest of
Rowan county. Some of these fields are located within the Grants Creek watershed (Helms
communications, 2002).
2.2.2 Failed Septic Systems
Failing septic systems have been cited as a potential source of fecal coliform bacteria to water
bodies (USEPA, 2000). The Department of Environmental Health has estimated that Rowan
County has approximately 25,365 housing units on septic systems (DEH, 1999). Septic system
failure rate data in North Carolina are very limited. A study conducted in 1981 by the North
Carolina Office of State Budget and Management suggested that approximately 11% of systems
that were surveyed experienced malfunctions or failures over a year (DEH, 2000).
2.2.3 Urban Development/Sanitary Sewer Overflows
Fecal coliform bacteria 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 systems overflows. The City of Salisbury owns and operates the Grants
Creek WWTP and the sewage collection system. The Sowers Ferry WWTP (Previously operated
by the town of Spencer) is currently operated by the City of Salisbury. In the last two years (July
1999 - June 2001), Salisbury reported at least 10 sanitary sewer overflows (SSOs) ranging from
500 gallons to 37,500 gallons (Salisbury, 2002).
Final Fecal Coliform TMDL for Grants Creek
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2.4 Wildlife
Wildlife can be a source of fecal coliform bacteria in forested, wetland, pasture and cropland
areas. Wildlife deposit fecal material in these areas which can be transported to a stream in a
rain event. Wildlife in the Rowan county area include deer, raccoons, squirrels, and birds
(including waterfowl).
3.0 MODELING APPROACH
3.1 Model Framework
The Coliform Routing and Allocation Program (CRAP), a geographic information system (GIS)
based tool (ArcView), was selected for the Grants Creek fecal coliform bacteria TMDL
evaluation in order to satisfy a variety of modeling objectives. CRAP is designed to be an easy to
use GIS based model for fecal coliform TMDL development. In 1998 the Modeling Unit staff
reviewed the available tools potentially suitable for use in fecal coliform TMDLs and determined
that most of the models examined tended to be either overly complex for the modeling objectives
or too simple and inflexible. With the notable exception of a few major urban areas, most fecal
impaired streams are located in watersheds where relatively little information is available on
sources and stream/watershed morphology. Monthly instream fecal concentration data, collected
at DWQ ambient stations, tends to comprise the bulk of the available data on fecal coliform
bacteria in these watersheds.
Hence, in 1999 Modeling Unit staff began development of a simple, flexible, steady state
modeling tool which could be applied in a variety of watersheds for which there is limited
available data. CRAP is a customized ArcView project, written in Avenue, ArcView’s scripting
language. Output from the model is intended to represent ‘typical’ instream fecal coliform
concentrations within a given time step, for predefined design (critical) conditions.
3.2 Model Setup
The Grants Creek watershed was delineated into 3 subwatersheds. The land areas of each of the
subwatersheds are shown in Table 5. The subwatersheds range in size from 15.9 mi2 to 33.9 mi2
and encompass pasture, cultivated lands, forest, and low and high density development lands.
Final Fecal Coliform TMDL for Grants Creek
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Table 5. The areas of the subwatersheds of the Grants Creek watershed.
Subwatershed Area (square miles)
WS01 15.9
WS02 33.9
WS03 17.9
Figure 7 illustrates the subwatershed delineations for the Grants Creek watershed. The
subwatershed delineations were based, in part, on the location of the ambient and discharger
coalition monitoring sites, the location of WWTPs, and the geographic extent of the impaired
segment of Grants Creek. Subwatershed WS01 contains the upstream areas including the source
of the creek near the Town of Landis, and the Town of China Grove. The outlet of subwatershed
WS01 is the located at SR1505, the site a DWQ’s special study sampling station. Subwatershed
WS02 covers the area upstream of Salisbury. The outlet of subwatershed WS02 is the located at
US 70 and 601, which is a monitoring location of DWQ’s special study. Subwatershed WS03 is
located downstream of the impaired segment and above the confluence of Grants Creek and
Yadkin River. This part of the watershed includes the City of Salisbury and is more developed
than the other two. The outlet of subwatershed WS03 is located downstream of the WWTP, the
site of the ambient monitoring station. The land cover coverage for the subwatersheds is shown
in Table 6.
Table 6. The land cover/land use coverage of the subwatersheds in the Grants Creek watershed.
Land Cover Watershed 01
acres (%)
Watershed 02
acres (%)
Watershed 03
acres (%)
Cultivated 829 (8.1%) 1323 (6.1%) 293 (2.5%)
High Intensity Development 163 (1.6%) 716 (3.3%) 1078 (9.4%)
Low Intensity Development 36 (0.4%) 130 (0.6%) 77 (0.7%)
Forest 4545 (44.6%) 12,454 (57.4%) 7290 (63.6%)
Herbaceous Cover 4526 (44.4%) 7030 (32.4 %) 2700 (23.6 %)
Open Water 93 (0.9%) 44 (0.2%) 19 (0.2%)
Total 10192 21697 11457
Final Fecal Coliform TMDL for Grants Creek
16
Figure 7. Grants Creek Watershed Subwatershed Delineations
3.2.1 Hydrology
Since Grants Creek is not gaged, flow information for Grants Creek was estimated using flow
data from the Second Creek USGS gage station near Barber, North Carolina (Station Number
02120780). This method of calculating flows for Grants Creek is based on the assumption of
equal flow and runoff per square mile for Grants and Second Creeks. Given the close proximity
and similarities in land cover between the two watersheds, this is a reasonable assumption. Prior
to calculating the flow of Grants Creek using areal weighting, the Second Creek flow was
adjusted to account for flows from WWTPs.
Final Fecal Coliform TMDL for Grants Creek
17
To estimate the daily flow of Grants Creek, an adjustment coefficient was established by
dividing the drainage area of Grants Creek (67.7 square miles) by the drainage area of the
Second Creek gage (118.00 square miles). This coefficient (0.57) was multiplied by the adjusted
daily flow of Second Creek to arrive at the estimates for Grants Creek. The flows from the
effluent of the WWTPs within the Grants Creek watershed were added to the subwatersheds
downstream of these facilities.
3.2.2 Hydraulics
There are several methods to estimate stream velocity based on stream flow data. The water
quality model utilized the power function to calculate the hydraulics of Grants Creek.
The power function: V = aQb
V = velocity (feet per second)
Q = stream flow (cubic feet per second)
a = flow coefficient (unitless)
b = exponent for flow (unitless)
Time-of-travel data (TOT) from die studies performed by the Environmental Sciences Branch
(ESB) in 1976 and 1986 along Grants Creek are used to estimate the values of the coefficient and
exponent for the Grants Creek hydraulics. The following values were used in the Grants Creek
model to calculate stream velocity: a = 0.19 and b = 0.33.
3.3 Fecal Coliform Source Representation
Both point sources and non-point sources of fecal coliform are represented in the Coliform
Routing and Allocation Program (CRAP) model. Figure 8 depicts the process the CRAP model
utilizes to calculate the fecal coliform loading from the non-point sources. Each of the non-point
sources of fecal coliform is linked to one or more land cover types (i.e., cattle grazing is linked to
herbaceous cover). Based on the assumption that flow yields from each of the land covers in the
watershed are equal per square mile, CRAP calculates the portion of the Grants Creek stream
flow that originates from each land cover type. To calculate the fecal coliform load from a
specific source, the calculated flow from the land cover type was multiplied by the assumed
Final Fecal Coliform TMDL for Grants Creek
18
monthly average or typical fecal coliform concentration under the modeled condition (either dry
or wet weather). The fecal coliform loading was calculated on a daily basis in the model runs.
Table 7 outlines the assumed average fecal coliform concentrations for both dry weather and wet
weather conditions.
Figure 8. A schematic diagram of the non-point source fecal coliform loading calculations
Source Average or Typical
ie Fecal Coliform Concentration
Cattle Grazing for the Modeled Condition
Land Cover (LC) Type
Pasture
Fecal Coliform Loading =
Fecal Coliform Conc. x
Flow from Land Area of LC Type
.
Final Fecal Coliform TMDL for Grants Creek
19
Table 7. Assumed Instream Fecal Coliform Concentrations by Source Category and Land Cover
for the Mean Flow Condition in the Subwatersheds.
Source
Category
Source
Sub-Category
Subwatershed Land Cover/
Land Use
Wet Weather
Assumed FC
Instream
Concentration
(cfu/100ml)
Dry Weather
Assumed FC
Instream
Concentration
(cfu/100ml)
Point Source WWTP WS02-WS03 Daily Loading
(From DMR)
Daily Loading
(From DMR)
Non-Point
Source
Wildlife WS01 – WS03 Forest 90 30
Livestock
Grazing
WS01 - WS02 Herbaceous/
Pasture
5000 500
Livestock
Grazing/ Land
Application
WS03 Herbaceous/
Pasture
1,000 500
Manure
Application
(Mar. – June;
Sept. – Dec.)
WS01, WS02 Herbaceous/
Pasture
5,000 500
Manure
Application
(Mar. – June;
Sept. – Nov.)
WS01, WS2 Cultivated 5,000 500
High Intensity
Development
(SSOs,
stormwater,
sewer
infiltration)
WS01- WS03 High Intensity
Developed
8,700 1,500
Low Intensity
Development
(include septic
system failure,
stormwater)
WS01 – WS03 Low Intensity
Developed
8,700 1,500
3.3.1 Wet Weather Versus Dry Weather Fecal Coliform Loading
The CRAP model can calculate fecal coliform loading on a daily time step during both dry and
wet weather conditions. For the Grants Creek TMDL application of the CRAP model, dry
weather conditions were defined as three consecutive days without recorded rainfall in Salisbury,
North Carolina. Wet weather days account for all of the remaining days. To calculate the daily
Final Fecal Coliform TMDL for Grants Creek
20
fecal coliform loadings, different in-stream concentrations are used for dry and wet weather
conditions.
3.3.2 NPDES Discharge
Grants Creek WWTP, a 7.5 MGD NPDES individually permitted facility, and Spencer WWTP, a
0.75 MGD plant, are located in subwatershed WS03. The daily fecal coliform loads from the
WWTPs within the subwatersheds were calculated by using the daily fecal coliform
concentration and daily discharges from the facilities as reported in the discharge monitoring
reports (DMR). The daily fecal coliform loads from January 1995 to September 2000 were used
as point source inputs in the model.
3.3.3 Livestock
3.3.3.1 Livestock Grazing
Fecal coliform loading from grazed areas was calculated using an instream fecal coliform
concentration for the portion of the stream flow that originates from pasturelands (managed
herbaceous and upland herbaceous land cover). Different fecal coliform concentrations were
used to calculate the fecal coliform bacteria loading during wet weather and dry weather events.
The increased fecal coliform loading on wet weather takes into account the increased fecal
coliform concentrations in stormwater runoff.
Site specific information on annual grazing patterns was not available, therefore it was assumed
that there is no monthly variation in animal grazing on pastureland throughout the year. Several
studies have indicated that grazing cattle increases instream fecal coliform concentrations.
Stephenson and Street (1978) observed that the presence of cattle on rangelands increased fecal
coliform concentrations in stream from 0 to 2500/100ml (Khaleel et al., 1980). Fecal coliform
concentrations from grazed pasture runoff have been measured in the range of 120 – 1.3 x 106
cfu/100ml (Doran et al, 1981). A fecal coliform concentration of 5,000 cfu/100ml for wet
weather days was input into the model to calculate the fecal coliform load from grazing livestock
in subwatersheds WS01 and WS02. Due to the small number of cattle in subwatershed WS03 a
fecal coliform concentration of 1,000 cfu/100ml was used to calculate the loads for wet weather
in WS03. The fecal coliform concentration used to calculate the load from grazing on dry
Final Fecal Coliform TMDL for Grants Creek
21
weather days was 500cfu/100ml for all subwatersheds. The fecal coliform concentrations used
in the CRAP model fall within the range of fecal coliform concentrations found in the literature.
3.3.3.2 Land Application of Agricultural Manure/Concentrated Animal Feedlot Operations
Fecal coliform loading values from the land application of manure, poultry litter and
concentrated animal feedlot operations were calculated in the model using an instream fecal
coliform concentration for the portion of the stream flow that originates from cultivated lands
and pasturelands (herbaceous land cover). Based on the information from Rowan Soil & Water
Conservation District and Cooperative Extension Offices, manure application is applied to
cropland from March-June and September-November (Rowan SWCD communications, 2002).
Manure is applied to pastureland during the same period but extending through December. Due
to a lack of site specific data on these sources, cattle and poultry manure application were
grouped together as one source, the land application of agricultural manure. Under wet weather
conditions, the manure application contribution to the instream fecal coliform concentration was
represented by a concentration of 5,000 cfu/100ml for the portion of the stream flow that
originates from pasturelands (herbaceous land cover) in WS01 and WS02. The application of
manure on cultivated lands was represented in the model by an input of 5,000 cfu/100ml fecal
coliform concentration for the portion of the stream flow that originates from cultivated land in
WS01 and WS02. Under dry weather conditions, the application of manure on cultivated lands
was represented in the model by an input of 500 cfu/100ml fecal coliform concentration for the
portion of the stream flow that originates on cultivated land. The fecal coliform loading from
manure application on pastureland in dry weather was calculated using an in-stream fecal
coliform concentration of 500 cfu/100ml for the portion of stream flow that originates on
pastureland.
3.3.4 Low Density Development/Septic Systems
Fecal coliform loading from developed land includes septic systems failure, leaking sanitary
sewers, illicit sanitary sewer connections and stormwater runoff (which can include waste from
domesticated animals and urban wildlife). Due to a lack of site specific data on these sources,
the fecal coliform loading from these sources were lumped together into one source category,
low density development. Several studies have been conducted to evaluate the effects of
Final Fecal Coliform TMDL for Grants Creek
22
development on stormwater runoff and instream fecal coliform concentrations. Farrell-Poe et al.
(1997) evaluated the effects of small rural municipalities on instream fecal coliform
concentrations in agricultural watersheds. Samples collected from perennial streams
downstream of four small municipalities (populations ranged from 561 to 4,829) were
statistically significantly higher than the upstream samples. Two of the four towns were serviced
by sanitary sewers, but none of the towns had stormwater drains. The mean differences of the
fecal coliform concentrations of upstream and downstream samples ranged from 21 to 294
cfu/100ml.
Geldreich et al. studied fecal coliform concentration levels in urban runoff from a suburban area
of Cincinnati, Ohio. The average fecal coliform concentrations of runoff water, collected
throughout the year, from a wooded hillside, street gutters and a business district were
635cfu/100ml, 13,420 cfu/100ml and 14,950 cfu/100ml respectively (Khaleel et al., 1980). Fecal
coliform concentration levels have been studied in Onondaga Lake and seven of its tributaries in
metropolitan Syracuse, New York (Canale et al., 1993). The dry weather fecal coliform
concentrations of the tributaries, which were monitored daily throughout the summer of 1987,
ranged from 108 cfu/100ml to 25,525 cfu/100ml. Intensive sampling during two storm events
was conducted from the onset of the storms until the hydrographs returned to base flow
conditions. The mean wet weather fecal coliform concentrations of the tributaries ranged from
>8,720 to 240,046 cfu/100ml. In the supporting documentation of P-Load, a component of the
USEPA BASINS model, the geometric mean of fecal coliform concentrations in stormwater
runoff from residential land in the Atlanta area was cited as 8,700 cfu/100ml. This fecal coliform
concentration value was based on the Atlanta Regional Storm Water Characterization Study
(ARSWCS) (BASINS, 2001).
Fecal coliform loading values from septic system failure, leaking sanitary sewers and stormwater
runoff from low intensity development were calculated in the model using an instream fecal
coliform concentration for the portion of the stream flow that originates from the low intensity
developed lands in the subwatersheds. The wet weather fecal coliform loading from low
intensity developed land was calculated in the model by multiplying a fecal coliform
concentration of 8700 cfu/100ml by the portion of the stream flow that originates from low
intensity developed land. The dry weather fecal coliform loading was calculated by multiplying
Final Fecal Coliform TMDL for Grants Creek
23
1500cfu/100ml by the portion of the stream flow that originates from low intensity developed
land.
3.3.5 High Density Development/ Sanitary Sewer Overflows
Fecal coliform bacteria from high intensity developed areas can originate from various sources
including runoff through storm sewers, illicit discharges of sanitary waste, overflowing sanitary
sewer systems, and leaking collection lines. Due to a lack of data on site specific fecal coliform
loadings from these sources, they were grouped together into one source class. The wet weather,
high density urban development loading was represented in the model by multiplying the
instream fecal coliform concentration of 8700 cfu/100ml to the portion of the stream flow that
originates from the high intensity developed lands. The dry weather loading was calculated by
multiplying the instream fecal coliform concentration of 1500 cfu/100ml by the portion of the
stream flow that originates from high intensity developed lands. This value falls within the range
of the urban dry weather instream fecal coliform concentrations which have been measured in
Mecklenburg County, North Carolina for the Fecal Coliform Total Maximum Daily Load for
Irwin, McAlpine, Little Sugar and Sugar Creek Watersheds (Mecklenburg County, 2001)
3.3.6 Wildlife
To represent the wildlife fecal coliform loading in dry weather conditions, a concentration of 30
col/100ml was multiplied by the portion of the Grants Creek stream flow that originates in
forested or shrubland areas. Under wet weather conditions, a concentration of 90 cfu/100ml was
used to calculate the wildlife loading. The State of South Carolina has estimated that the
geometric mean of fecal coliform concentrations in waterbodies that flow through forested areas
in South Carolina during all flow conditions is 30 col/100ml (SCDHEC, 1999). The Center for
Watershed Protection (1999) has cited a fecal coliform concentration range of 10-100 cfu/100ml
for forest runoff.
3.4 Instream Decay Rate
Once fecal coliform bacteria reach a waterbody, environmental factors influence the extent of
their growth and decay. Physical factors that influence the bacteria populations include photo-
oxidation, adsorption, flocculation, coagulation, sedimentation and temperature (USEPA, 1985).
Chemical toxicity, pH, nutrient levels, algae and the presence of fecal matter may also influence
Final Fecal Coliform TMDL for Grants Creek
24
the fecal coliform populations. The water quality model utilizes a first order decay rate to
calculate instream decay of fecal coliform bacteria.
Ct = Coe-kt
C= coliform concentration (cfu/100ml)
Co= initial coliform concentration (cfu/100ml)
Ct= coliform concentration at time t (cfu/100ml)
k= decay rate constant (day-1)
t = exposure time (days)
Bacterial die-off has been modeled as a first-order decay equation, using a decay rate value
between 0.7/day and 1.5/day (Center for Watershed Protection, 1999). In the Grants Creek
model, a decay rate value of 0.8/day was used for the existing condition and allocation runs.
3.5 Uncertainty
The lack of agreement between modeled and observed fecal coliform concentrations is due in
part to the high degree of uncertainty associated with predicting any water quality variable,
especially fecal coliform. The inability to accurately predict specific observed fecal coliform
concentrations can be attributed to model error, lack of sufficient information in source
assessment, gaps in our scientific knowledge, natural variability in instream fecal coliform
concentrations, field and laboratory measurement error, and lack of current site specific model
input parameters including decay rate, flow, rainfall data and landuse information. The available
models used to predict fecal coliform concentrations are not adept at characterizing prediction
uncertainty. The Coliform Routing and Allocation Program (CRAP) was intended to predict
daily average fecal coliform concentrations based on land use information. Due to the lack of site
specific information, literature values were used to calculate the fecal coliform loadings from the
various landuses. Because uncertainty associated with CRAP is expected to be large, the model
results should be interpreted in light of the model limitations and prediction uncertainty. Simple
models like CRAP can be used to guide initial decision making but continued observation of the
watershed and stream, as fecal coliform controls are implemented (e.g., exclusion fencing, leaky
sanitary sewer repairs), is expected to be our best approach for determining the appropriate level
of management.
Final Fecal Coliform TMDL for Grants Creek
25
3.6 Critical Conditions
Fecal coliform pollution in the Grants Creek watershed originates from both point and non-point
sources. The critical conditions for waterbodies impaired by point sources typically occur during
periods of dry weather, while those impaired by non-point sources generally occur in periods of
wet weather. The Grants Creek fecal coliform monitoring data indicate that elevated levels of
fecal coliform occur during both dry and wet weather conditions. The model was run for a 5.75
year simulation period using estimated daily stream flows. The highest 30-day geometric mean
of the predicted daily fecal coliform concentration, 1433 cfu/100ml, occurred between April 14
and May 13, 1998. Rain was recorded in Salisbury 14 days during the 30 day period. As a result,
wet weather days accounted for 28 of the 30 day critical period.
3.7 Model Results
The predicted daily fecal coliform concentrations over the 5.75 years simulation period along
with the ambient monitoring data collected by DWQ at the model evaluation location are shown
in Figures 9. The observed 30-day geometric mean fecal coliform concentrations at downstream
locations of Spencer WWTP and Grants Creek WWTP between January, 1997 and May, 1998
were compared to the predicted concentrations at the same location. The results are shown in
Figures 10 and 11. The model evaluation location is located at the DWQ ambient monitoring
station downstream of the Grants Creek WWTP near Spencer. The modeling results indicate
that non-point source fecal coliform loading has a significant impact on instream fecal coliform
concentrations in the Grants Creek watershed. The Spencer WWTP (Sowers Ferry WWTP) is
permitted to discharge a monthly geometric mean fecal coliform concentration of 200 cfu/100ml
with a maximum permitted discharge of 0.75 MGD. While the WWTP is permitted at the
200cfu/100ml level, the plant has discharged much less than the permitted load. The Grants
Creek WWTP (7.5 MGD) has moved its discharge location to the Yadkin River since September,
2000. Therefore, the fecal coliform load from this WWTP is only used in the model prior to
September 2000.
The predicted 30-day rolling geometric mean fecal coliform concentrations for the 5.75 year
simulation period are shown in Figure 12. Throughout the 5.75 year modeled period, 96 percent
of the rolling 30-day geometric means of the predicted values are greater than 200cfu/100ml.
The 30-day geometric means range in value from 115 cfu/100ml to 1433 cfu/100ml.
Final Fecal Coliform TMDL for Grants Creek
26
Figure 9. Grants Creek Simulated and Observed Fecal Coliform Bacteria
Concentrations at DWQ’s Ambient Monitoring Location
1
10
100
1000
10000
100000
1/1/1995 10/1/1995 7/1/1996 4/1/1997 1/1/1998 10/1/1998 7/1/1999 4/1/2000
Date
Fe
c
a
l
C
o
l
i
f
o
r
m
C
o
n
c
e
n
t
r
a
t
i
o
n
s
(
c
f
u
/
1
0
0
m
L
)
Predicted Observed
Figure 10. Grants Creek 1997-1998 Predicted Vs. Observed 30-day Rolling Geometric Mean
of FC Concentrations (Data from Spencer WWTP (NC0025593) downstream Monitoring)
10
100
1000
10000
1/3/1997 3/3/1997 5/3/1997 7/3/1997 9/3/1997 11/3/1997 1/3/1998 3/3/1998 5/3/1998
Date
Fe
c
a
l
C
o
l
i
f
o
r
m
C
o
n
c
e
n
t
r
a
t
i
o
n
s
(c
f
u
/
1
0
0
m
l
)
Downstream WQ Standard Predicted
Final Fecal Coliform TMDL for Grants Creek
27
Figure 11. Grants Creek 1997-1998 Predicted Vs. Observed 30-day Rolling Geometric Mean
of FC Concentrations (Data from Salisbury WWTP(NC0023884) downstream Monitoring)
1
10
100
1000
10000
1/3/1997 3/4/1997 5/3/1997 7/2/1997 8/31/199710/30/199712/29/19972/27/1998 4/28/1998
Date
Fe
c
a
l
C
o
l
i
f
o
r
m
C
o
n
c
e
n
t
r
a
t
i
o
n
s
(
c
f
u
/
1
0
0
m
l
)
Observed Value Predicted Value Water Quality Standard
Figure 12. Grants Creek Simulated 30-day Rolling Geometric Mean of Fecal Coliform
Bacteria Concentrations at DWQ’s Ambient Monitoring Location
10
210
410
610
810
1010
1210
1410
1/1/1995 10/1/1995 7/1/1996 4/1/1997 1/1/1998 10/1/1998 7/1/1999 4/1/2000
Date
Fe
c
a
l
C
o
l
i
f
o
r
m
C
o
n
c
e
n
t
r
a
t
i
o
n
s
(c
f
u
/
1
0
0
m
L
)
Predicted Water Quality Standard
Final Fecal Coliform TMDL for Grants Creek
28
4.0 ALLOCATION
4.1 Total Maximum Daily Load
A total maximum daily load is the total amount of pollutant that can be assimilated by the
receiving water body while achieving water quality standards. A TMDL is comprised of the sum
of wasteload allocations (WLA) for point sources, load allocations (LA) for non-point sources
and a margin of safety (MOS). This definition is expressed by the equation:
TMDL = WLAs + LAs + MOS
The objective of the TMDL is to estimate allowable pollutant loads and to allocate to the known
pollutant sources in the watershed so the appropriate control measures can be implemented and
the water quality standard can be achieved. 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. In the Grants Creek fecal coliform TMDL, loads are calculated based on
stream flow and instream fecal coliform concentrations that originate from a specific source/land
cover.
4.2 Seasonal Variation
The model was run over a 5.75 years simulation period under varying daily flow conditions in
order to capture seasonal flow fluctuations. The contribution of fecal coliform bacteria from the
various sources also varied throughout the year to reflect changes in fecal coliform loading due
to monthly changes in agricultural management practices.
4.3 Margin of Safety
The margin of safety (MOS) may be incorporated into a TMDL either implicitly, through the use
of conservative assumptions to develop the allocations, or explicitly through a reduction in the
TMDL target. For the Grants Creek watershed, an explicit margin of safety was incorporated in
the modeling analysis by setting the TMDL target at 175cfu/100ml, which is 25cfu/100ml lower
(12.5%) than the water quality target of 200cfu/100ml.
Final Fecal Coliform TMDL for Grants Creek
29
4.4 Load Reduction
Figure 13 shows the predicted 30-day rolling geometric mean of fecal coliform concentrations
with the final allocation to meet the 175 cfu/100ml target.
The final allocation of fecal coliform loads are shown in Table 8 (wet weather) and Table 9 (dry
weather). The values given in Tables 8 and 9 represent the fecal coliform concentrations from
each landuse category and the load allocations necessary to meet the water quality standard at the
evaluation location. The 30-day running geometric means of the predicted fecal coliform
concentrations with the final fecal coliform allocations at the evaluation location are shown in
Figure 13.
In order to reach the water quality target of 200 cfu/100ml, with a 25 cfu/100ml explicit margin
of safety, the non-point source fecal coliform loading needs to be reduced by 33%-60% for the
various sources in dry weather conditions and 85%-97% reductions in wet weather conditions.
The NPDES individually permitted Grants Creek WWTPs discharge a small portion of the
modeled fecal coliform loading into the Grants Creek watershed and have consistently met their
Figure 13. Grants Creek 30-day Rolling Geometric Mean of Fecal Coliform
Bacteria Concentrations for the Simulated and the Allocation Scenarios
10
100
1000
10000
1/1/1995 10/1/1995 7/1/1996 4/1/1997 1/1/1998 10/1/1998 7/1/1999 4/1/2000
Date
Fe
c
a
l
C
o
l
i
f
o
r
m
C
o
n
c
e
n
t
r
a
t
i
o
n
s
(
c
f
u
/
1
0
0
m
L
)
Predicted Water Quality Standard MOS Allocation
Final Fecal Coliform TMDL for Grants Creek
30
monthly discharge limit. Therefore, the TMDL allocation is limited to the fecal coliform loading
reductions on the non-point sources. Table 10 presents the Total Maximum Daily Load of fecal
coliform bacteria.
The TMDL allocation model shows that the reduction scenario that meets the 200 cfu/100ml
geometric mean standard also meets the instantaneous standard of 400 cfu/100ml over the 5.75
year model period. Therefore, the load reduction scenario presented in Tables 8 and 9 satisfy the
portion of the standard that limits the percentage of instantaneous excursions over 400cfu/100ml
to twenty percent.
Table 8. Wet Weather instream Fecal Coliform Load Reductions for Subwatersheds in the
Grants Creek Watershed.
Source
Category
Source Sub-
Category
Subwatershed Simulation FC
Concentration
(cfu/100ml)
Allocation FC
Concentration
(cfu/100ml)
%
Reduction
Point-
Source
(WLA)
WWTP WS03 Daily Loading
(From DMR)
200 0%
Non-Point
Source
(LA)
Wildlife WS01-WS03 90 90 0%
High Density
Development
(stormwater,
SSOs, sewer
exfiltration)
WS01-WS03 8,700 500 94%
Low Density
Development
(septic systems)
WS01-WS03 8700 500 94%
Livestock
Grazing/Manure
Application
(Pastureland)
WS1-WS02 5,000 grazing
5,000 manure
application
300
(150 grazing/
150 man.
app.)
97%
Manure
Application
(Cultivated)
WS01-WS02 5,000 150 97%
Livestock
Grazing/Land
Application
WS03 1000 150 85%
Final Fecal Coliform TMDL for Grants Creek
31
Table 9. Dry Weather instream Fecal Coliform Load Reductions for Subwatersheds in the
Grants Creek Watershed.
Source
Category
Source Sub-
Category
Subwatershed Simulation FC
Concentration
(cfu/100ml)
Allocation FC
Concentration
(cfu/100ml)
%
Reduction
Point-
Source
(WLA)
WWTP WS02-WS3 Daily Loading
(From DMR)
200 0%
Non-Point
Source (LA)
Wildlife WS01-WS03 30 30 0%
High Density
Development
(stormwater,
SSOs, sewer
exfiltration)
WS01-WS03 1500 1000 33%
Low Density
Development
(septic systems)
WS01-WS03 1500 1000 33%
Livestock
Grazing/Manure
Application
(Pastureland)
WS01-WS02 500 grazing/
500 manure
application
400
(200 grazing/
200 man.
app.)
60%
Manure
Application
(Cultivated)
WS01-WS02 500 200 60%
Livestock
Grazing/Land
Application
WS03 500 300 40%
Table 10. Total Maximum Daily Load of fecal coliform bacteria during the critical period.
Wasteload Allocation
(WLA)
(counts/30 days)
Load Allocation
(LA)
(counts/30 days)
Explicit Margin of Safety
(MOS)
(counts/30 days)
TMDL
(counts/30 days)
1.75 x 1011 2.18 x 1013 3.14 x 1012 2.51 x 1013
Final Fecal Coliform TMDL for Grants Creek
32
5.0 SUMMARY AND FUTURE CONSIDERATIONS
The sources of fecal coliform in the Grants Creek watershed include urban sources in the Landis,
China Grove and Salisbury areas, livestock grazing and manure application on agricultural lands
and pasture lands, and wildlife in the forested areas of the watershed. The Coliform Routing and
Allocation Program was utilized to simulate instream fecal concentrations and to allocate the
fecal coliform loads to the various sources. In order for the water quality target to be met, the
final allocation of the fecal coliform loads requires a non-point source load reduction between
33%-60% under dry weather conditions and 85%-97% under wet weather conditions for the
various non-point sources of fecal coliform. The model estimated that the Grants Creek WWTPs
contribute insignificant percentage of the total fecal coliform loading in the watershed.
Therefore, the reduction allocation focuses on the fecal coliform loading from non-point sources.
5.1 Monitoring
Fecal coliform monitoring will continue on a monthly interval at the ambient monitoring site (at
Spencer) and at the discharger coalition monitoring sites. The continued monitoring of 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. In addition to this
data collection, further fecal coliform monitoring may be considered. Additional monitoring
beyond the ambient and discharger stations’ monitoring could aid in a fecal coliform source
assessment in the watershed and further aid in the evaluation of the progress towards meeting the
water quality target and the water quality standard. A bacteria source tracking study of the
Grants Creek watershed, to help determine the portion of fecal coliform loads derived from
humans versus animals throughout the watershed, is considered as a part of the future monitoring
of Grants Creek.
To comply with EPA guidance, North Carolina may adopt new bacteria standards utilizing
Escherichia coli (E. coli) and enterococci in the near future. Thus, future monitoring efforts to
measure compliance with this TMDL should include using the E. coli and enterococci. Per EPA
recommendations (EPA, 2000c), 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.
Final Fecal Coliform TMDL for Grants Creek
33
5.2 Implementation
An implementation plan is not included in this TMDL. The involvement of local governments
and agencies will be needed in order to develop implementation plans. The Rowan County
Environmental Services, Rowan County Soil and Water Conservation District and, the Land
Trust of Central North Carolina have shown interest in use restoration projects in the Grants
Creek Watershed. The Land Trust of Central North Carolina is already undertaking projects
along the Grants Creek Corridor. The Division of Water Quality will assist the local
governments and agencies in developing the implementation plan for this TMDL.
6.0 PUBLIC PARTICIPATION
The City of Salisbury, and Rowan County have been notified of DWQ’s intention to develop the
Grants Creek Fecal Coliform TMDL. Rowan County Environmental Services, Cooperative
Extension Service and Soil and Water Conservation District have supplied agricultural
information to aid in the source assessment portion of the TMDL.
A draft of the Grants Creek Fecal Coliform TMDL was publicly noticed through various means,
including notification in a local newspaper and published Cooperative Extension Newsletter. The
TMDL was also available from the Division of Water Quality’s website
(http://h2o.enr.state.nc.us/tmdl/draft_TMDLS.htm) during the comment period. A public
meeting to discuss the Grants Creek Fecal Coliform TMDL was held in Salisbury on May 8,
2002. A public comment period was held for the thirty days prior to May 24th, 2002.
Final Fecal Coliform TMDL for Grants Creek
34
REFERENCES
BASINS 3.0 Beta 2001. U.S. Environmental Protection Agency. P-Load Reference Guide
Canale, R.P., Auer, M.T., Owens, E.M., Heidtke, T.M., and S.W. Effler. 1993. Modeling Fecal
Coliform Bacteria-II. Model Development and Application. Wat. Res. 27(4):703-714.
Center for Watershed Protection. 1999. Microbes and Urban Watersheds: Concentrations,
Sources and Pathways. Watershed Protection Techniques 3(1): 554:565.
City of Salisbury. 2002. Personal communication with Eric Helms. March 2002.
City of Salisbury. 2002. City of Salisbury Collection System Overflows (July 1999- June 2000).
City of Salisbury Utility Management Department.
Division of Environmental Health (DEH). NCDENR. 1999. North Carolina On-Site Wastewater
Non-Point Source (NPS) Pollution Program. www.deh.enr.state.nc.us/oww/non-
pointsource/NPS.htm June 24, 1999.
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).
March 15, 2000.
Doran, J.W., J.S. Schepers, and N.P. Swanson. 1981. Chemical and bacteriological quality of
pasture runoff. Journal of Soil and Water Conservation May-June: 166-171.
Intensive Survey Unit. 1986. Grants Creek Survey. Intensive Survey Report for Grants Creek.
Environmental Sciences Branch, North Carolina Division of Water Quality.
Farrell-Poe, K.L., Ranjha, A.Y. and S. Ramalingam. 1997. Bacterial Contributions by Rural
Municipalities in Agricultural Watersheds. Trans of the ASAE, 40(1) 97-101.
Khaleel, R. Reddy, K.R. and M.R. Overcash. 1980. Transport of Potential Pollutants in Runoff
Water from Land Areas Receiving Animal Wastes: A Review. Water Research 14: 421-436.
Mecklenburg County Department of Environmental Protection. 2001. Public Review Draft
Fecal Coliform Total Maximum Daily Load for Irwin, McAlpine, Little Sugar and Sugar Creek
Watersheds.
North Carolina Department of Agriculture. 2001. Agricultural Statistics Division-County
Statistics. www.ncagr.com/stats/cntysumm/ and http://govinfo.library.orst.edu/cgi-bin/ag-
state?North+Carolina.
Rider, B. 2002. Rowan Soil & Water Conservation District. Personal communication with Bruce
Rider. February 2002.
Tad, H. S. 2002. Rowan County Health Department. 2002. Personal communication with Tad H.
Stetler. February 2002.
Final Fecal Coliform TMDL for Grants Creek
35
Rowan County Extension Service. 2001. Personal communication with Jim Cowden. January
2002.
Schueler, Thomas R. 1994. The importance of imperviousness. Watershed Protection
Techniques, Vol. 1, no. 3. Center for Watershed Protection, Silver Spring, MD.
South Carolina Department of Health and Environmental Control. Total maximum Daily Load
Development for Camp Creek CW-235 Fecal Coliform. August 17, 1999.
Stephenson, G.R. and L.V. Street. 1978. Bacterial Variations in streams from a
southwest Idaho rangeland watershed. J. Environ. Qual. 7:150-157
The Triangle Group, 2001. Grants Creek Watershed Management Plan, Rowan County, North
Carolina. Clean Water Management Trust Fund Project Agreement No. 1998B-017
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, Federal Advisory Committee (FACA). Draft final
TMDL Federal Advisory Committee Report. 4/28/98.
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) 2000c. 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) 1985. Rates, constants, and kinetics
formulations in surface water quality modeling (II ed.). Athens, GA: EPA-600-3-85-040.
Final Fecal Coliform TMDL for Grants Creek
36
Appendix I. Grants Creek Ambient Monitoring Station Q4600000 Fecal Coliform
Concentration Monitoring Data
Date Instream Fecal
Coliform Concentration
(cfu/100ml)
Date Instream Fecal
Coliform Concentration (cfu/100ml)
04/27/95 380 05/06/98 240
05/23/95 490 06/08/98 320
06/26/95 50 07/09/98 10
07/20/95 590 08/05/98 27
08/15/95 190 09/17/98 210
09/11/95 17000 10/08/98 390
10/19/95 280 11/02/98 280
11/08/95 800 12/15/98 570
12/14/95 150 01/07/99 210
01/10/96 190 02/15/99 600
02/22/96 210 03/11/99 43
03/11/96 340 04/13/99 91
04/09/96 1000 05/10/99 36
05/07/96 820 06/21/99 570
06/11/96 3800 08/02/99 480
07/29/96 730 08/24/99 230
08/12/96 6600 09/27/99 920
09/25/96 10000 10/25/99 140
10/22/96 54 11/15/99 60
11/13/96 310 12/16/99 170
12/10/96 10 02/15/00 570
01/16/97 4000 03/13/00 230
02/19/97 260 04/17/00 250
03/18/97 340 05/15/00 18
05/21/97 210 06/07/00 270
06/19/97 630 07/24/00 1200
07/28/97 460 08/15/00 2000
08/19/97 210 09/12/00 2000
09/17/97 200 10/05/00 300
10/22/97 650 11/06/00 140
11/17/97 330 12/11/00 210
12/11/97 64 01/17/01 81
01/13/98 480 02/12/01 2400
02/12/98 210 03/17/01
03/10/98 1400 04/17/01 160
04/07/98 320 04/17/01 160
*L= Actual value is known to be greater than value given.
J= Estimated value.
A= Value reported is the mean of two or more determination.
Final Fecal Coliform TMDL for Grants Creek
37
Appendix II. Grants Creek DWQ Special Study Monitoring Data
Grants Creek in Rowan Co. at SR 1505
Dates Number of
days
Observations Geometric Mean
4/11/2001 to 5/9/2001 29 15 662
4/18/2001 to 5/16/2001 29 15 852
4/25/2001 to 5/23/2001 29 15 1187
5/2/2001 to 5/30/2001 29 15 855
Grants Creek in Rowan Co. at 70-601
Dates Number of
days
Observations Geometric Mean
4/11/2001 to 5/9/2001 29 15 469
4/18/2001 to 5/16/2001 29 15 473
4/25/2001 to 5/23/2001 29 15 758
5/2/2001 to 5/30/2001 29 15 474
Grants Creek downstream Spencer WWTP outfall
Dates Number of
days
Observations Geometric Mean
4/11/2001 to 5/9/2001 29 15 284
4/18/2001 to 5/16/2001 29 15 338
4/25/2001 to 5/23/2001 29 15 678
5/2/2001 to 5/30/2001 29 15 528
All Station Summary
Dates Number of
days
Observations Geometric Mean
4/11/2001 to 5/9/2001 29 45 445
4/18/2001 to 5/16/2001 29 45 514
4/25/2001 to 5/23/2001 29 45 848
5/2/2001 to 5/30/2001 29 45 598
Final Fecal Coliform TMDL for Grants Creek
38
Appendix III. Yadkin Pee-Dee River Basin Association Discharger Coalition
Fecal Coliform Concentration Monitoring Data
Date Instream Fecal Coliform
Concentration
(cfu/100ml)
Date Instream Fecal Coliform
Concentration
(cfu/100ml)
Grants Creek at Third Extension near
Spencer (Q4540000)
Grants Creek below Salisbury & Spencer WWTP at
DWQ’s Ambient Station NC02120975 (Q4600000)
6/3/1998 330 6/3/1998 400
7/16/1998 130 7/16/1998 1
8/4/1998 700 8/4/1998 150
9/2/1998 6000 9/2/1998 87
10/21/1998 293 10/21/1998 268
11/12/1998 360 11/12/1998 310
12/4/1998 590 12/4/1998 205
1/7/1999 340 1/7/1999 420
2/10/1999 180 2/10/1999 240
3/11/1999 26 3/11/1999 3
4/8/1999 250 4/8/1999 520
5/6/1999 180 5/6/1999 200
6/9/1999 440 6/9/1999 340
7/15/1999 100 7/15/1999 370
8/4/1999 350 8/4/1999 200
9/15/1999 680 9/15/1999 370
10/14/1999 190 10/14/1999 300
11/4/1999 190 11/4/1999 250
12/9/1999 100 12/9/1999 64
1/13/2000 840 1/13/2000 840
2/14/2000 5500 2/14/2000 4900
3/20/2000 3900 3/20/2000 4300
4/27/2000 48 4/27/2000 100
5/4/2000 130 5/4/2000 340
6/15/2000 520 6/15/2000 760
7/19/2000 240 7/19/2000 280
9/12/2000 550 9/12/2000 100
10/23/2000 260 10/23/2000 260
11/13/2000 180 11/13/2000 240
12/26/2000 63 12/26/2000 120
1/22/2001 210 1/22/2001 140
2/12/2001 1000 2/12/2001 1700
3/21/2001 2900 3/21/2001 4800
4/9/2001 210 4/9/2001 230
5/14/2001 390 5/14/2001 130
6/6/2001 500 6/6/2001 140
7/17/2001 18 8/7/2001 53
8/7/2001 41 9/11/2001 290
9/11/2001 220 10/9/2001 5
10/9/2001 180
Final Fecal Coliform TMDL for Grants Creek
39
Appendix IV. Spencer WWTP Upstream/ Downstream Fecal Coliform Bacteria
Monitoring Data (NC0025593)
Date upstream Downstream Date Upstream Downstream Date Upstream Downstream
01/06/97 1420 1350 07/08/97 583 367 09/30/97 5400 5400
01/13/97 195 240 07/09/97 416 533 10/01/97 460 260
01/20/97 60 92 07/14/97 235 368 10/06/97 290 255
01/27/97 72 16 07/15/97 290 285 10/13/97 180 165
02/03/97 198 208 07/16/97 381 210 10/20/97 5100 4900
02/10/97 750 650 07/21/97 500 300 10/28/97 3700 3600
02/17/97 1980 360 07/22/97 7300 3000 11/03/97 500 320
02/24/97 207 210 07/23/97 6000 6000 11/10/97 333 290
03/03/97 1080 660 07/28/97 567 600 11/17/97 275 240
03/10/97 119 132 07/29/97 517 633 11/25/97 520 470
03/17/97 358 459 07/30/97 367 165 12/02/97 3700 5400
03/24/97 292 233 08/04/97 195 215 12/08/97 280 290
03/31/97 647 510 08/05/97 260 140 12/15/97 270 300
04/07/97 3360 3300 08/06/97 767 867 12/22/97 205 130
04/14/97 523 438 08/11/97 2550 3150 12/29/97 640 520
04/21/97 66 86 08/12/97 560 550 01/05/98 1500 1250
05/01/97 2130 2640 08/13/97 480 250 01/12/98 1000 1600
05/03/97 250 170 08/18/97 295 205 01/21/98 2400 300
05/12/97 212 168 08/19/97 190 175 01/26/98 433 300
05/19/97 168 132 08/20/97 195 81 02/02/98 767 250
05/27/97 2010 600 08/25/97 76000 76000 02/09/98 260 105
06/02/97 1260 2130 08/26/97 5800 5500 02/16/98 190 200
06/03/97 1365 1200 08/27/97 980 760 02/26/98 270 260
06/04/97 1000 1650 09/02/97 185 155 03/01/98 153 130
06/09/97 350 430 09/03/97 760 185 03/12/98 1300 1250
06/10/97 1800 1800 09/04/97 65 26 03/16/98 210 67
06/11/97 400 283 09/08/97 500 205 03/24/98 533 366
06/16/97 700 783 09/09/97 285 220 03/31/98 500 620
06/17/97 1300 1000 09/10/97 260 195 04/07/98 267 387
06/18/97 867 933 09/15/97 620 810 04/13/98 383 358
06/23/97 239 360 09/16/97 100 58 04/22/98 350 270
06/24/97 4750 4750 09/17/97 165 195 04/27/98 367 386
06/25/97 3000 3000 09/22/97 155 32 05/04/98 1075 950
06/30/97 433 333 09/23/97 6000 6000 05/13/98 567 517
07/01/97 43 235 09/24/97 3700 3600 05/18/98 780 520
07/02/97 2700 2550 09/29/97 200 225 05/26/98 1400 1250
07/07/97 287 417
Final Fecal Coliform TMDL for Grants Creek
40
Appendix V. Grants Creek WWTP (Salisbury) Upstream/ Downstream Fecal Coliform
Bacteria Monitoring Data (NC0023884)
Date upstream DS-I1 DS-II1 Date upstream DS-I DS-II Date upstream DS-I DS-II
1/2/97 370 200 230 7/1/97 727 330 109 9/17/97 330 209 127
1/6/97 4100 3000 2700 7/2/97 6000 6000 6000 9/22/97 250 6000 127
1/14/97 520 91 240 7/7/97 664 380 200 9/23/97 450 6000 590
1/21/97 320 240 127 7/8/97 918 460 155 9/26/97 370 440 380
1/27/97 210 64 127 7/9/97 746 470 91 10/1/97 420 700 109
2/3/97 420 210 7/14/97 400 240 136 10/6/97 410 164 182
2/10/97 550 410 7/15/97 550 230 64 10/13/97 250 127
2/17/97 855 164 1182 7/16/97 45 310 9 10/23/97 480 9900
2/24/97 240 155 155 7/21/97 3600 500 136 10/27/97 6000 6000 6000
3/1/97 520 310 540 7/22/97 27 6000 164 11/3/97 600 310 380
3/11/97 220 450 145 7/25/97 10000 34000 5500 11/10/97 360 300
3/18/97 270 210 280 7/28/97 8 10 490 11/19/97 240 3700
3/24/97 400 210 136 7/29/97 927 1300 420 11/24/97 855 590
4/1/97 155 240 200 7/31/97 3700 3000 2100 1/5/98 320 136 33
4/8/97 818 673 3100 8/4/97 370 280 64 1/12/98 600 3800 6000
4/16/97 610 182 178 8/5/97 390 340 127 1/20/98 1700 1600 4700
4/21/97 310 200 400 8/6/97 580 590 320 1/26/98 400 340 360
5/5/97 570 440 440 8/11/97 6500 7800 310 2/2/98 500 280 91
5/12/97 220 182 145 8/12/97 580 460 300 2/9/98 510 340 64
5/20/97 280 182 127 8/13/97 470 370 280 2/19/98 2200 4500 736
5/27/97 6100 5800 10900 8/18/97 1127 764 10 2/24/98 645 636 818
6/2/97 1464 1164 591 8/19/97 360 270 46 3/1/98 560 390
6/3/97 1236 936 609 8/20/97 430 340 73 3/9/98 10700 8700
6/4/97 1164 727 4000 8/25/97 664 410 64 3/19/98 6200 7000 4400
6/9/97 382 364 209 8/26/97 2100 6000 191 3/23/98 5200 4800 5700
6/10/97 540 11100 1100 8/28/97 330 360 82 3/30/98 450 440 145
6/11/97 770 460 1300 9/2/97 470 200 46 4/6/98 710 550 410
6/16/97 2400 2400 1900 9/3/97 300 320 64 4/13/98 400 390 210
6/18/97 2900 900 1146 9/4/97 6000 210 82 4/20/98 60000 60000 60000
6/19/97 855 709 570 9/8/97 520 460 36 4/27/98 727 410 420
6/23/97 673 430 295 9/9/97 755 300 64 5/4/98 2400 1500
6/24/97 636 6300 290 9/10/97 7100 10900 220 5/11/98 5800 6000
6/25/97 850 470 1191 9/15/97 570 136 155 5/18/98 550 570 340
6/30/97 600 470 118 9/16/97 460 320 127 5/26/98 560 420 173
1DS-I = Downstream, DS-II= Downstream II
Final Fecal Coliform TMDL for Grants Creek
41
Appendix VI. Public Notification of Grants Creek Fecal Coliform TMDL
Rocky River, Yadkin-Pee Dee River Basin
Grants Creek, Yadkin-Pee Dee River Basin
Now Available Upon Request
Rocky River (in Subbasin 03-07-11)
Fecal Coliform Total Maximum Daily Load
Grants Creek (in Subbasin 03-07-04)
Fecal Coliform Total Maximum Daily Load
Are now available upon request from the North Carolina Division of Water Quality. These TMDL studies were
prepared as a requirement of the Federal Water Pollution Control Act, Section 303(d). The studies identify the
sources of pollution, determine allowable loads to the surface waters, and suggest allocations for pollutants of
concern.
TO OBTAIN A FREE COPY OF THE TMDL REPORTS:
Please contact Ms. Robin Markham (919) 733-5083, extension 558 or write to:
Ms. Betsy Albright
Water Quality Planning Branch
NC Division of Water Quality
1617 Mail Service Center
Raleigh, NC 27699-1617
Interested parties are invited to comment on the draft TMDL study by May 24, 2002. Comments and questions concerning the reports
should be directed to Ms. Betsy Albright (ext. 514) at the above number and address. The draft TMDLs are also located on the
following website: http://h2o.enr.state.nc.us/tmdl
Public Meetings Notice
Rocky River TMDL Grants Creek TMDL
A public meeting to discuss the Rocky A public meeting to discuss the
River Fecal Coliform TMDL will be held Grants Creek Fecal Coliform TMDL
On Wednesday, May 8th at 11:00am at will be held on Wednesday, May 8th
the following address: at 3:30pm at the following address
DENR Mooresville Regional Office Rowan County Center
919 North Main Street 2727-A Old Concord Road
Mooresville, NC 28115 Salisbury, NC 28146
Final Fecal Coliform TMDL for Grants Creek
42
Final Fecal Coliform TMDL for Grants Creek
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Final Fecal Coliform TMDL for Grants Creek
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Final Fecal Coliform TMDL for Grants Creek
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Appendix VII. Public Comments and Response to Comments on the Public Review Draft
of the Grants Creek Fecal Coliform TMDL
Final Fecal Coliform TMDL for Grants Creek
46
Final Fecal Coliform TMDL for Grants Creek
47
Appendix VII. DWQ Response to Public Comment on the Public Review
Draft of the Grants Creek Fecal Coliform TMDL
The North Carolina Division of Water Quality welcomes the comments from the
North Carolina Farm Bureau Federation. As sited in the TMDL, the Coliform
Routing and Allocation Program is a simple model and is used by DWQ when
there is a dearth in site-specific fecal coliform concentration data. DWQ
recognizes that there is uncertainty associated with the modeling and input data
used in the modeling. Where there was not site specific or North Carolina based
data available, an extensive literature review was conducted in order to determine
the most appropriate input values for the CRAP model. DWQ recognizes that the
land cover/land use is from 1996 and uncertainty in the modeling exists because
of the age of this data. However, DWQ has recently conducted watershed
reconnaissance and feels that the model appropriately approximates the presence
and absence of livestock throughout the watershed. Watershed specific livestock
data was obtained from Rowan County Soil and Water Conservation District
office, and North Carolina Cooperative Extension office.
The hydrology portion of the model is based on daily flow values which were
calculated using an aerial weighting approach utilizing a gaged stream in a nearby
watershed. These flows were adjusted to account for the discharge from Waste
Water Treatment Plants (WWTPs) within the watershed.
The model assumes that livestock grazing and manure application occur mainly in
watersheds 01-02. Livestock grazing and land applications were minimal in
watershed 03. Therefore, the area around Salisbury (WS03) did not include
manure application in the model. The CRAP model is based on average
conditions, while manure might not be deposited or applied every day throughout
a specified period, fecal coliform polluted runoff does occur after manure has
been deposited or applied. Stephenson and Street (1978), and Jawson et al.
(1982) have determined that elevated levels of bacteria may persist in pasture
runoff months after cattle have been removed from the pastureland.
Due to the level of uncertainty in the modeling assumptions and the input data,
the DWQ supports an adaptive management approach to reducing the fecal
coliform levels within Grants Creek. We very much welcome the North Carolina
Farm Bureau Federation’s involvement in developing a fecal coliform
management strategy for the Grants Creek.
References:
Stephenson, G.R. and L.V. Street. 1978. Bacterial Variations in streams from a
southwest Idaho rangeland watershed. J. Environ. Qual. 7:150-57
Jawson, M.D., L.F. Elliot, K.E. Saxton, and D.M. Fortier. 1982. The effect of
cattle grazing on indicator bacteria in runoff from a Pacific Northwest watershed.
J. Environ. Qual. 11:621-7