NewfoundCreekApprovedFCTMDL

Total Maximum Daily Loads for
Fecal Coliform for
Newfound Creek,
North Carolina
[Waterbody ID NC_6-84b, Waterbody ID NC_6-84c,
Waterbody ID NC_6-84d]

Final Report
January 2005
(Approved February 8, 2005)

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

With support from:
Tetra Tech, Inc.
Cape Fear Bldg., Suite 105
3200 Chapel Hill-Nelson Hwy.
Research Triangle Park, NC 27709
Upper French Broad River Basin

Newfound Creek TMDL – Final Version Submitted to EPA January 2005

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Table of Contents
List of Tables .............................................................................................................................iii
List of Figures .............................................................................................................................iv
Summary Sheet ..............................................................................................................................v
1 Introduction..............................................................................................................................1
1.1 Problem Definition.......................................................................................................................................1
1.1.1 TMDL Components.............................................................................................................................2
1.1.2 Newfound Creek Fecal Coliform Impairments ...................................................................................2
1.2 Watershed Description.................................................................................................................................3
1.2.1 Land Use Distribution in the Newfound Creek Watersheds................................................................3
1.3 Flow Gaging.................................................................................................................................................5
1.4 Water Quality Monitoring............................................................................................................................6
1.4.1 NCDENR Monitoring..........................................................................................................................7
1.4.2 USGS Monitoring................................................................................................................................8
1.4.3 BCSWCD Monitoring.......................................................................................................................10
2 Source Assessment.................................................................................................................11
2.1 General Sources of Fecal Coliform............................................................................................................11
2.1.1 Nonpoint Source Fecal Coliform Contributions................................................................................11
2.1.2 Summary of Fecal Coliform Trends..................................................................................................18
2.1.3 Point Source Fecal Coliform Contributions.......................................................................................20
3 Technical Approach...............................................................................................................21
3.1 TMDL Endpoints .......................................................................................................................................21
3.2 Load-Duration Curves for Fecal Coliform.................................................................................................21
3.3 Determination of Existing Fecal Coliform Load and Assimilative Capacity.............................................25
3.3.1 Instantaneous (20 Percent) Criterion .................................................................................................25
3.3.2 Geometric Mean Criterion.................................................................................................................32
3.3.3 Source Assessment............................................................................................................................33
4 TMDL Development..............................................................................................................39
4.1 TMDL Definition.......................................................................................................................................39
4.2 TMDL Endpoints .......................................................................................................................................39
4.3 Critical Conditions .....................................................................................................................................39
4.4 Seasonal Variations....................................................................................................................................39
4.5 Margin of Safety (MOS) ............................................................................................................................40
4.6 Load Allocation..........................................................................................................................................40
4.7 TMDL Summary........................................................................................................................................41
5 Report Summary....................................................................................................................43
6 TMDL Implementation Plan..................................................................................................45
7 Stream Monitoring.................................................................................................................47
8 Future Efforts.........................................................................................................................49
9 Public Participation................................................................................................................51
10 Further Information................................................................................................................53
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11 References ............................................................................................................................55
Appendix A Water Quality Sampling Data...........................................................................A-1
Appendix B Assimilative Capacity and Load Reduction Calculations................................. B-1
Appendix C Public Notice.....................................................................................................C-1
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List of Tables
Table 1. Land Use for the Newfound Creek Watershed, Acreage and Percent
Composition (TVA, 2002).......................................................................................................3
Table 2. Flow Statistics for USGS Gage 03451690 (Newfound Creek at Jenkins Valley Road)........... 5
Table 3. Relative Proportion of Flow at USGS Gage 03451690 (Newfound Creek at Jenkins Valley
Road) for Each Monitoring Station Drainage Area .................................................................. 6
Table 4. Summary of NCDENR Water Quality Monitoring for Fecal Coliform Impairment................ 8
Table 5. Summary of USGS Coliform Monitoring Data ........................................................................ 9
Table 6. BCSWCD Fecal Coliform Monitoring Data........................................................................... 10
Table 7. Description of TVA Septic System Conditions ...................................................................... 16
Table 8. TVA Riparian Buffer Classification ....................................................................................... 17
Table 9. Condition of Riparian Buffers Along Perennial Streams in the Newfound Creek
Watershed (TVA, 2002)..........................................................................................................17
Table 10. Summary of Pollutant Loadings Upstream of the NCDENR Monitoring Sites...................... 19
Table 11. Fecal Coliform Target Load and Reduction Requirements Calculated Using the Load-
Duration Curve Approach at Jenkins Valley Road................................................................. 30
Table 12. Fecal Coliform Target Load and Reduction Requirements Calculated Using the Load-
Duration Curve Approach at Highway 63 .............................................................................. 30
Table 13. Fecal Coliform Target Load and Reduction Requirements Calculated Using the Load-
Duration Curve Approach at McPeters Road.......................................................................... 31
Table 14. Livestock Fecal Coliform Bacteria Production Rates............................................................. 35
Table 15. Fecal Coliform Bacteria Production Rates For Wildlife Species............................................ 35
Table 16. Summary of Estimated Reductions......................................................................................... 41
Table 17. TMDL Reductions for Fecal Coliform ...................................................................................41
Table 18. Newfound Creek TMDL Components.................................................................................... 41
Table A-1. NCDENR Ambient Monitoring Data for Newfound Creek at Jenkins
Valley Road (1996-1999)......................................................................................................A-3
Table A-2. NCDENR Special Study Monitoring Data for Newfound Creek at Jenkins
Valley Road (2003)...............................................................................................................A-4
Table A-3. NCDENR Ambient Monitoring Data for Newfound Creek
at Highway 63 (1996-1999)..................................................................................................A-5
Table A-4. NCDENR Special Study Monitoring Data for Newfound Creek
at Highway 63 (2003) ...........................................................................................................A-6
Table A-5. NCDENR Ambient Monitoring Data for Newfound Creek at
McPeters Road (1996-1999).................................................................................................A-7
Table A-6. USGS Monitoring Data for Stations on Newfound Creek and Tributaries (1997, 2003)....A-8
Table A-7. Buncombe County Monitoring Data for Stations on Newfound Creek
and Tributaries (2002-2004) .................................................................................................A-8
Table B-1. Regression of Natural Logarithm of Fecal Coliform Load on Flow
Frequency, Newfound Creek at Jenkins Valley Road........................................................... B-3
Table B-2. Regression of Natural Logarithm of Fecal Coliform Load on Flow
Frequency, Newfound Creek at Highway 63........................................................................ B-4

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List of Figures
Figure 1. Location of Newfound Creek in Western Buncombe County............................................... 1
Figure 2. Newfound Creek Watershed Land Use (TVA, 2002)............................................................ 4
Figure 3. Newfound Creek Monitoring Locations................................................................................ 7
Figure 4. Percent Impervious Cover in the Newfound Creek Watershed (TVA, 2002) ..................... 12
Figure 5. Animal Operations in the Newfound Creek Watershed (TVA, 2002)................................. 13
Figure 6. Animal Access to Streams (TVA, 2002) ............................................................................. 14
Figure 7. Location and Type of Septic Systems in the Newfound Creek Watershed (TVA, 2002).... 15
Figure 8. Condition of Septic Systems in the Newfound Creek Watershed (TVA, 2002).................. 16
Figure 9. Riparian Condition Along Perennial Streams in the Newfound Creek Watershed
(TVA, 2002) ........................................................................................................................ 18
Figure 10. Newfound Creek Monitoring Data at Three NCDENR Sites.............................................. 19
Figure 11. Flow Regimes for USGS Gage 03451690............................................................................. 6
Figure 12. Flow-Duration Curve for NCDENR and USGS Fecal Coliform Data for
Newfound Creek at Jenkins Valley Road (1/27/96 through 6/20/03).................................. 22
Figure 13. Flow-Duration Curve for NCDENR Fecal Coliform Data for Newfound Creek at
Highway 63 (11/25/96 through 6/20/03) ............................................................................. 23
Figure 14. Flow-Duration Curve for NCDENR Fecal Coliform Data for Newfound Creek
at McPeters Road (12/1/96 through 6/1/99)......................................................................... 23
Figure 15. Regression Analysis of the Instantaneous Fecal Coliform Load-Duration Curve,
Jenkins Valley Road ............................................................................................................27
Figure 16. Regression Analysis of the Instantaneous Fecal Coliform Load-Duration Curve,
Highway 63.......................................................................................................................... 28
Figure 17. Regression Analysis of the Instantaneous Fecal Coliform Load-Duration Curve,
McPeters Road..................................................................................................................... 29
Figure 18. Reductions Needed in Fecal Coliform Loading Along Newfound Creek to Meet the
Instantaneous Standard........................................................................................................ 31
Figure 19. Geometric Mean Fecal Coliform Load-Duration Curves for Newfound Creek at
Jenkins Valley Road ............................................................................................................32
Figure 20. Geometric Mean Fecal Coliform Load-Duration Curves for Newfound Creek at
Highway 63.......................................................................................................................... 33
Figure 21. Fecal Coliform Loading by Source in the Newfound Creek Watershed ............................. 36
Figure 22. Fecal Coliform Loading by Subwatershed in the Newfound Creek Watershed.................. 37
Figure 23. Flow Duration Curve of NCDENR Fecal Coliform Data for Newfound Creek
at Jenkins Valley Road (12/1/96 through 6/1/99) with Summer and Winter
Observations Distinguished................................................................................................. 40

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SUMMARY SHEET
Total Maximum Daily Load (TMDL)

1. 303(d) Listed Waterbody Information
State: North Carolina
County: Buncombe
Major River Basin: Upper French Broad River Basin
Watershed: Newfound Creek in Upper French Broad River Watershed HUC 06010105

Impaired Waterbody (2002 303(d) List):
Waterbody Name - (ID) Water Quality Classification Impairment Length (mi)
Newfound Creek
NC_6-84b Class C Waters Fecal Coliform 1.3
Newfound Creek
NC_6-84c Class C Waters Fecal Coliform 2.3
Newfound Creek
NC_6-84d Class C Waters Fecal Coliform 6.6

Constituent(s) of Concern: Fecal Coliform Bacteria
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.
2. TMDL Development
Analysis/Modeling:
Load duration curves for fecal coliform bacteria were based on cumulative frequency distribution of
flow conditions in the watershed. A predictive upper confidence limit about the regression line on
load versus flow is compared to a criterion limit curve, calculated as the load that would occur at 90
percent of the water quality criterion (thus incorporating a margin of safety). Necessary reductions
in load are calculated as the maximum distance between the confidence-bound on the regression
line and the limit curve.
Critical Conditions:
Critical conditions are accounted for in the load curve analysis by determining the 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.
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Seasonal Variation:
Seasonal variation in hydrology, climatic conditions, and watershed activities are represented
through the use of continuous flow estimates and the use of all readily available water quality data
collected in the watershed.
3. Allocation Watershed/Stream Reach
Segment Pollutant Existing WLA1 LA MOS2
Reduction
Required TMDL
Newfound
Creek
Fecal
coliform
(counts/day)
3.62x1012 0.00 2.61x1011 Explicit
10% MOS 92.8% 2.90x1011
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.

4. Public Notice Date:
November 15th, 2004
5. Submittal Date: January 6th, 2005
6. Establishment Date:
7. Endangered Species (yes or blank):
8. EPA Lead on TMDL (EPA or blank):
9. TMDL Considers Point Source, Nonpoint Source, or both: Nonpoint Source

Newfound Creek TMDL – Final Version Submitted to EPA January 2005

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1 Introduction
This report presents the development of a Total Maximum Daily Load (TMDL) for fecal coliform
impairment of Newfound Creek. Newfound Creek near Asheville, North Carolina has been placed on the
North Carolina 2002 list of impaired waters (the 303(d) list) and requires estimation of a TMDL for fecal
coliform to meet the water quality standards specified for Class C waters. Newfound Creek is a
headwater tributary to the French Broad River, located within Buncombe County (Figure 1), draining an
area of approximately 34.7 square miles.

Figure 1. Location of Newfound Creek in Western Buncombe County
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 having 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.
BUNCOMBE COUNTY
Asheville
Fletcher
Woodfin
Black Mountain
Montreat
Weaverville
County Boundary
Municipalities
French Broad River
Newfound Creek Tributaries
Newfound Creek
Listed Reaches
10 0 10 Miles
N
BUNCOMBE COUNTY
Asheville
Fletcher
Woodfin
Black Mountain
Montreat
Weaverville
County Boundary
Municipalities
French Broad River
Newfound Creek Tributaries
Newfound Creek
Listed Reaches
10 0 10 Miles
N
BUNCOMBE COUNTY
Asheville
Fletcher
Woodfin
Black Mountain
Montreat
Weaverville
County Boundary
Municipalities
French Broad River
Newfound Creek Tributaries
Newfound Creek
Listed Reaches
10 0 10 Miles
N
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1.1.1 TMDL Components
The 303(d) process requires that a 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, 1999) 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 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.
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 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 Newfound Creek Fecal Coliform Impairments
The Newfound Creek listings are contained in the North Carolina Water Quality Assessment and
Impaired Waters List (2002 Integrated 305(b) and 303(d) Report) (NCDENR, 2003). The segments of
Newfound Creek considered impaired due to fecal coliform [Waterbody ID NC_6-84b, NC_6-84c, NC_6-
84d] extend 10.2 miles from State Road 1296 to the French Broad River. Potential sources listed are
non-urban development, agriculture, and pasture grazing in upland and riparian areas.
Newfound Creek has a designated use classification of Class C, which is intended to protect aquatic life
and secondary recreational uses (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
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rainfall events and, in some cases, this violation is expected to be caused by uncontrollable
nonpoint source pollution; all coliform concentrations are to be analyzed using the membrane
filter technique unless high turbidity or other adverse conditions necessitate the tube dilution
method; in case of controversy over results, the MPN 5-tube dilution technique will be used as
the reference method.
1.2 WATERSHED DESCRIPTION
Newfound Creek is located within Buncombe County in North Carolina (Figure 1). Newfound Creek
extends 14.5 miles from its headwaters to the French Broad River (NC Subbasin 40301) and includes
approximately 35.5 miles of mainstem and tributary perennial stream reaches. The creek drains
approximately 34.7 square miles of land.
1.2.1 Land Use Distribution in the Newfound Creek Watersheds
Aerial photographs of the Newfound Creek Watershed were taken by the Tennessee Valley Authority in
the year 2000 for purposes of developing a nonpoint source pollution inventory of the watershed. The
land use distributions reported by TVA (2002) are summarized in this report and form the basis of the
land use analysis.
Land use distribution was tabulated for the entire Newfound Creek Watershed. As shown in Table 1, the
watershed is primarily forest (45.2 percent), pasture (35.4 percent), and residential land uses (14.7
percent). The upper portion of the watershed is primarily forest land in the headwaters with pasture and
single family residential land uses along the streams (Figure 2). In the lower parts of the watershed, the
land uses are primarily single family residential and pasture land with relatively less forested area.

Table 1. Land Use for the Newfound Creek Watershed, Acreage and Percent Composition
(TVA, 2002)
Land Use Forest
Pasture,
Grass Residential Row Crop
Comm,
Ind, Trans Other Total
Area (ac) 10,029.4 7,866.7 3,266.2 757.7 179.6 90.0 22,189.7
Area (%) 45.20% 35.45% 14.72% 3.41% 0.81% 0.41% 100.00%
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2
1412
17
1
68
3
11
13
9
15
4
16
10
5
7
TVA Landuse 2000
Single family, low density (< 2/acre)
Subdivision under construction
Single family, under construction
Mobile home park
Farmstead with accompanying structures
Commercial, service, institutional
Auto junkyard
Commercial, service, institutional under construction
Dumpsites
Educational
Religious
Industrial
Major highway right of way
Electric transmission right of way
Row crop: no residue, (0 to 10%)
Row crop: with residue, (>30%)
Row crop: medium residue (10 to 30%)
Good pasture: well maintained
Fair pasture: uneven growth and condition
Heavily overgrazed pasture
Poor pasture: sparse cover, steep slopes, often gullies
Shrub and brush: old field, volunteer woody growth
Forest land
Harvested forest land
Water
Disturbed area: little or no cover, non-agricultural area
Subwatersheds
2 0 2 4 Miles
N

Figure 2. Newfound Creek Watershed Land Use (TVA, 2002)
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1.3 FLOW GAGING
The U.S. Geological Survey (USGS) began monitoring flow on Newfound Creek at Jenkins Valley Road
(Gage 03451690) in December 2000. Flow statistics for the gage are presented in Table 2 and Figure 3.
Newfound Creek flow prior to December 2000 could not be scaled from nearby watersheds because the
watersheds were either too large or differed significantly in land use distribution. Two of the larger
watersheds had similar land use characteristics to the Newfound Creek Watershed: USGS 03453000 on
Ivy River near Marshall and USGS 03500240 on Cartoogechaye Creek near Franklin. The Ivy River
watershed is 57 square miles, and the Cartoogechaye watershed is 158 square miles. Flows prior to
December 2000 were estimated for Newfound Creek by a regression analysis dependent on flows at the
two gages. The natural log of flow at the Newfound Creek gage was regressed on the natural log of flow
from the Ivy River and Cartoogechaye gages. As a result of the regression, the following equation was
used to estimate flow for Newfound Creek.
FNF = 0.21FC
0.44 FIV
0.45 where FNF = Newfound Creek Flow (cfs);
FC = Cartoogechaye Creek Flow (cfs); and
FIV = Ivy River Flow (cfs)
The above equation explains nearly 80 percent of the variability in Newfound Creek flow (R2= 0.79) and
estimates reliable flows greater than the 10th percentile (flows less than 28 cfs). Gaged and estimated
flows on Newfound Creek were scaled to each monitoring station based on drainage area using the
proportions in Table 3. These proportions represent the ratio of monitoring station drainage area to
gaging station drainage area.
Table 2. Flow Statistics for USGS Gage 03451690 (Newfound Creek at Jenkins Valley Road)
Flow Parameter Value (cfs)
Mean 16.1
Min 1.8
Max 694
High flow range > 30
Transitional flow range 19 - 30
Typical flow range 8 - 19
Low flow range < 8

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1
10
100
1000
0% 20% 40% 60% 80% 100%
Flow Duration Interval (%)
Fl
o
w

(
c
f
s
)
Drought
Low flowsTypical flows
Transi-
tional
flows
High
flows
19 cfs
8 cfs
30 cfs
Flood

Figure 3. Flow Regimes for USGS Gage 03451690 (Newfound Creek at Jenkins Valley Road)

Table 3. Relative Proportion of Flow at USGS Gage 03451690 (Newfound Creek at Jenkins
Valley Road) for Each Monitoring Station Drainage Area
Stream Station Relative Proportion of Gage Flow
Newfound Creek Jenkins Valley Road (SR 1641) 1.00
Newfound Creek Highway 63 0.47
Newfound Creek McPeters Road 0.061

1.4 WATER QUALITY MONITORING
Water quality monitoring in the Newfound Creek Watershed has been conducted by three agencies
(Figure 4). Data are presented in Appendix A. The North Carolina Department of Environment and
Natural Resources (NCDENR) collected fecal coliform samples from three locations in the watershed
from October 1996 through June 2003. Samples were collected at McPeters Road, Highway 63, and
Jenkins Valley Road. The U.S. Geological Survey (USGS) collected fecal coliform samples on
5/28/2003 and 11/19/2003 at four locations along Newfound Creek (Haylandy Drive, State Road 1297,
Old Newfound Road, and Jenkins Valley Road) and one location on Round Hill Branch at Rabbit Ham
Road. The Buncombe County Soil and Water Conservation District (BCSWCD) began monitoring fecal
coliform in April 2002 at ten locations in the watershed: four on Newfound Creek, four on Round Hill
Branch, and two on Morgan Branch.
Water quality monitoring performed by NCDENR for fecal coliform has shown a number of excursions
above the water quality standard at all three monitoring locations. Additional fecal coliform monitoring
data, collected by the USGS and BCSWCD further supports the decision to list Newfound Creek for fecal
coliform impairment.
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Newfound Creek
Round Hill Branch
Newfound Creek
Morgan Branch
Round Hill Branch
5A5B
3A
2B
2A
1B
6A
6B
3B
1A
1
5
6
7
10 McPeters
Highway 63
Jenkins ValleySubwatersheds
Newfound Creek Stream Network

USGS

NCDENR
BCSWCD
2 0 2 4 Miles
N

Figure 4. Newfound Creek Monitoring Locations

1.4.1 NCDENR Monitoring
Water quality monitoring in Newfound Creek was performed by NCDENR at three stations (Figure 4).
Regular monitoring was performed at McPeters Road for the period from 12/16/1996 through 6/14/1999,
at Highway 63 from 11/25/1996 through 6/14/1999, and at Jenkins Valley Road from 10/22/1996 through
6/14/1999. These data were collected approximately monthly. At Highway 63 and Jenkins Valley Road,
intensive fecal coliform monitoring was performed during the period from 4/14/2003 through 6/20/2003
to assess the impairment status with regards to the standards specification requiring five samples per 30-
day period. Table 4 presents a summary of the fecal coliform data collected. Fecal coliform
concentrations are expressed as number of colony forming units and may be written as “#/100 mL” or
“cfu/100 mL.”
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Table 4. Summary of NCDENR Water Quality Monitoring for Fecal Coliform Impairment
Station Period
Minimum;
Mean
Instantaneous
Criterion
Excursions/
Observationsa
Percent
Instantaneous
Criterion
Excursions
Geomean
Criterion
Excursions/
Observationsb
Newfound Creek
at McPeters Road 12/96 – 6/99
12
1800
281
5/21 23.8% nac
Newfound Creek
at Highway 63 11/96 – 6/03
140
57,000
6,694
23/30 76.7% 3/3
Newfound Creek
at Jenkins Valley
Road
10/96 – 6/03
20
65,000
3,804
27/35 77.1% 5/5
a Criterion excursions (Instantaneous fecal coliform measurements > 400 cfu/100 mL)/Total number of samples
b Criterion excursions (Geometric mean of 5 fecal coliform measurements within a 30-day period > 200 cfu/100
mL)/Number of 5-sample groups within a 30-day period
c Sample number requirements for geometric mean calculation not met

The McPeters Road monitoring station is not along the listed portion of Newfound Creek, but monitoring
data indicate that the instantaneous standard is exceeded more than 20 percent of the time.
1.4.2 USGS Monitoring
In the year 2003, USGS began monitoring coliform concentrations in the Newfound Creek Watershed to
address concerns of bacterial contamination and to identify target areas for BMPs. Two sampling events,
one low flow and one high flow, have been conducted at ten locations in the watershed. Fecal coliform
was measured at five sites (1, 5, 6, 7, 10) (Figure 4); E. coli was measured at all ten. To distinguish
between animal or human sources of contamination, serotyping was performed at five locations; however,
these results are not yet available.
The USGS data is presented in Table 5. During the low flow event, the instantaneous standard for fecal
coliform was exceeded at four of five locations. During the high flow event, the instantaneous standard
was exceeded at all five locations sampled.

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Table 5. Summary of USGS Coliform Monitoring Data
Low Flow Event (5/28/2003) High Flow Event (11/19/2003)
Station E. coli (#/100mL)
Fecal Coliform
(#/100mL) E. coli (#/100mL)
Fecal Coliform
(#/100mL)
1. Newfound Creek at
Jenkins Valley Rd. 1,300 930 27,000 24,000
5. Newfound Creek at
Old Newfound Rd. 1,100 1,400 22,000 29,000
6. Round Hill Branch
at Rabbit Ham Rd. 130 140 20,000 6,000
7. Newfound Creek at
Browntown Rd. 2,400 8,700 18,000 11,000
10. Newfound Creek at
Haylandy Drive 670 1,300 4,700 2,900
Minimum 130 140 4,700 2,900
Maximum 2,400 8,700 27,000 29,000
Mean 1,120 2,494 18,340 14,580

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1.4.3 BCSWCD Monitoring
The Buncombe County Soil and Water Conservation District (BCSWCD) has been monitoring fecal
coliform concentrations in the Newfound Creek Watershed since April 2002 (Figure 4). Ten sites are
currently monitored, four on Newfound Creek, four on Round Hill Branch, and two on Morgan Branch.
A summary of data collected is presented in Table 6. No valid 30-day geometric means can be calculated
from this data set.
Table 6. BCSWCD Fecal Coliform Monitoring Data
Site
Number Site Name
Minimum;
Mean
Instantaneous
Criterion
Excursions/
Observationsa
1A Brookshire #2, Worley’s Farm 46
6,000
1,513
19/32
1B Dark Cove Rd. 200
47,000
6,226
30/32
2A Duckett Residence/Off Newfound Rd. 100
22,600
3,261
28/32
2B Newfound Community Center/ Corner of Newfound Rd. &
Morgan Branch Rd.
520
12,000
3,105
32/32
3A Janice Buckner Dairy BMP/ Green Valley Rd. 178
32,500
3,936
26/32
3B Janice Buckner BMP/ Rabbit Ham Rd. 100
31,000
2,812
24/32
5A Inez Brown Beef Cattle Farm/ Green Valley Rd. 137
69,000
5,974
14/20
5B Downstream Inez Brown/ Green Valley Rd. 455
59,500
10,099
20/20
6A Max Morgan Upstream 940
1,160
1,050
2/2
6B Max Morgan Downstream 1,200b 1/1
a Criterion excursions (Instantaneous fecal coliform measurements > 400 cfu/100 mL)/Total number of samples
b Only one sample collected.

Newfound Creek TMDL – Final Version Submitted to EPA January 2005

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2 Source Assessment
A critical step in developing a useful and defensible TMDL is the assessment of potential sources of
contamination. Tetra Tech primarily relied upon the recent TVA (2002) nonpoint source pollution
inventory to categorize the major sources in the Newfound Creek Watershed including septic systems,
land use runoff, and animal operations. An estimate of wildlife contributions was added. These sources
are summarized in this section of the report. There are currently no point sources in the watershed.
2.1 GENERAL SOURCES OF FECAL COLIFORM
Both point and nonpoint sources may contribute fecal coliform bacteria to 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 sources such as agricultural activities and wildlife
contributions. Septic systems, illicit discharges, broken sewer pipes, and stormwater runoff can be
potential sources in urban areas.
Potential sources of fecal coliform loading in the watershed were identified based on an evaluation of
current land use/cover, septic system usage, and animal operation data. The source assessment was used
as the basis of the TMDL allocations.
2.1.1 Nonpoint Source Fecal Coliform Contributions
Research was performed to assess the most probable nonpoint sources of fecal coliform. Information on
sources was gathered from the TVA nonpoint source pollution inventory (2002), GIS information, census
data, and personal communication with local and state officials. The principal sources investigated were
land use runoff, animal operations, septic systems, and wildlife populations.
Runoff Contributions
Runoff from land uses in the watershed can contribute significant fecal coliform loading to streams.
Stormwater runoff carries animal feces from urban areas, pasture, and other agricultural lands near
streams.
A land use map of the Newfound Creek Watershed is presented in Figure 2. In general, the watershed can
be divided roughly into two halves: the forested upstream areas and the agricultural/residential
downstream areas. Throughout the watershed, single family residential and pasturelands are adjacent to
almost every stream reach. Thus, it is likely that runoff contributes to the instream fecal coliform load.
TVA estimated the percent of impervious cover from land use and land cover data obtained during the
nonpoint source pollution inventory. Figure 5 shows the percent impervious cover from land uses in the
Newfound Creek Watershed (imperviousness due to roads is not depicted). Impervious surfaces in urban
areas cause an increase in runoff volumes and pollutant loadings. The majority of the Newfound Creek
Watershed is rural, and 97 percent of the watershed is classified as having a percent imperviousness of
less than 10 percent.
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2
1412
17
1
68
3
11
13
9
15
4
16
10
5
7
Percent Impervious Cover
0 - 10
11 - 20
21 - 30
31 - 40
41 - 50
51 - 60
61 - 70
71 - 80
80 - 90
91 - 100
Subwatersheds
2 0 2 4 Miles
N

Figure 5. Percent Impervious Cover in the Newfound Creek Watershed (TVA, 2002)
Animal Operations
Pasture land represents 35 percent of the Newfound Creek Watershed area and in some subwatersheds
comprises as much as 68 percent of the total area. The nonpoint source pollution inventory (TVA, 2002)
contains data on the type, size, and location of each animal operation in the watershed. There are
approximately 1,680 beef cattle in the watershed, and over 73 percent are located on land that is adjacent
to a perennial or intermittent stream. There are approximately 930 dairy cows in the watershed, and all
are located on land that is adjacent to a perennial or intermittent stream. There are approximately 20
swine in the watershed; all are confined, but located on land that is adjacent to a perennial or intermittent
stream. The horse population in the watershed is approximately 165, and over 27 percent are on land that
is adjacent to a perennial or intermittent stream. There are no poultry houses reported. Figure 6 shows
the type and location of each animal operation in the watershed.
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2
14
12
17
1
68
3
11
13
9
15
4
16
10
5
7
Subwatersheds
Stream Network
Livestock
Cattle
Dairy

Horse
Swine
2 0 2 4 Miles
N

Figure 6. Animal Operations in the Newfound Creek Watershed (TVA, 2002)
The TVA also inventoried animal access to streams for those farms located adjacent to streams (Figure 7).
Of the 141,983 feet of perennial and intermittent streams in the Newfound Creek Watershed that were
inventoried, 3,386 feet show signs of direct and constant animal access; 67,598 feet show probable animal
access (animals are present on adjacent land and no animal barriers are in place; 71,000 feet are classified
as potential animal access (no signs of animal access currently present).
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2
14
12
17
1
68
3
11
13
9
15
4
16
10
5
7
Subwatersheds
Stream Network
Animal Access to Stream
Direct Access
Probable Access
Potential Access
2 0 2 4 Miles
N

Figure 7. Animal Access to Streams (TVA, 2002)
Septic Systems
Septic tanks are one of several possible causes of low flow exceedances. Other sources of low flow fecal
coliform loading are illicit discharges or other direct inputs of raw sewage. Figure 8 shows the location
and type of septic systems in the watershed as reported in the TVA nonpoint source pollution inventory.
There is no sewer service in the watershed.
In Newfound Creek, low flow exceedances have been measured at all three NCDENR monitoring
stations. Septic systems are one possible source of low flow fecal coliform loading in these areas,
particularly where residential land uses are adjacent to the streams. Older septic systems, like sand filters,
may be responsible for a large portion of the fecal coliform loading, depending on their location and
condition. TVA reported the condition of each septic system (Figure 9, Table 7) in the watershed based
on the moisture patterns surrounding drain fields that were detected by aerial photography. Of the 687
systems inventoried, one has a distinctive moisture pattern indicative of ponding, 110 have a suspicious
moisture pattern but no visible drain field, 16 have no apparent plume and appear to be properly
functioning, and the 560 remaining systems are suspect due to their location near rock outcrops, streams,
or on very steep slopes.

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2
14
12
17
1
68
3
11
13
9
15
4
16
10
5
7
Subwatersheds
Stream Network
Septic Systems
Commercial
House
Mobile Home
2 0 2 4 Miles
N

Figure 8. Location and Type of Septic Systems in the Newfound Creek Watershed (TVA, 2002)
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2
14
12
17
1
6
8
3
11
13
9
15
4
16
10
5
7
Subwatersheds
Stream Network
Septic

Distinctive Moisture Pattern

Suspicious Moisture Pattern

Distinctive Drain Field

Suspect Location
2 0 2 4 Miles
N

Figure 9. Condition of Septic Systems in the Newfound Creek Watershed (TVA, 2002)

Table 7. Description of TVA Septic System Conditions
Condition Description
Distinctive
moisture
pattern
Effluent plume from visible drain field pattern or prominent ponding down slope from the drain field
Suspicious
moisture
pattern
Visible plume pattern, but no drain field apparent; can be straight-pipe from septic system, roof
drainage, gray water disposal or natural seepage/spring
Distinctive
drain field
Visible drain field pattern, but no plume evident; may indicate slow leaching, but no apparent breakout
of a seasonally or hydraulically stressed system; or evapotranspiration characteristics of a functioning
system or newly installed system
Suspect
Location
No plume or drain field visible; home sites on very steep slope, small lots, visible rock outcrops, or in
close proximity to streams or reservoirs, especially those on heavily-wooded lots

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Riparian Buffer Disturbance
A well maintained stream buffer provides several benefits including the filtration of nutrients, sediment,
and pathogens. To assess the functionality of riparian corridors along the streams in the Newfound Creek
Watershed, the TVA categorized the width and percent cover for buffers along the perennial streams.
Areas on the left and right banks were then classified as “adequate,” “marginal,” or “inadequate” based on
a matrix of buffer width and percent vegetated cover. The matrix as defined by TVA (2002) is depicted
in Table 8. Results of the inventory are presented in Table 9 and Figure 10.
Table 8. TVA Riparian Buffer Classification
Buffer Width 0 to 33 Percent Cover 34 to 66 Percent Cover 67 to 100 Percent Cover
0 to 25 feet Inadequate Marginal Marginal
26 to 100 feet Marginal Marginal Adequate
Over 100 feet Marginal Adequate Adequate

Table 9. Condition of Riparian Buffers Along Perennial Streams in the Newfound Creek
Watershed (TVA, 2002)
Length (feet) Percent Condition
49,520 29.24% Inadequate on Both Banks
15,390 9.09% Inadequate on One Bank
73,100 43.16% Marginal on Both Banks
19,050 11.25% Marginal on One Bank
12,310 7.27% Adequate on Both Banks
169,370 100.00% Total Length Inventoried
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2
1412
17
1
68
3
11
13
9
15
4
16
10
5
7
Subwatersheds
Riparian Buffer Condition
Both Inadequate
One Inadequate
Both Marginal
One Marginal
Both Adequate
2 0 2 4 Miles
N

Figure 10. Riparian Condition Along Perennial Streams in the Newfound Creek Watershed
(TVA, 2002)
2.1.2 Summary of Fecal Coliform Trends
The data collected by NCDENR, USGS, and BCSWCD show elevated fecal coliform concentrations
during storm events as well as during typical and low flow periods. Because criterion excursions occur
across all flow regimes, a wide range of sources may contribute to stream impairment.
Comparison of fecal coliform concentrations at the three NCDENR sites shows an increasing trend in
concentration in the downstream direction (Figure 11). In fact, the most upstream site at McPeters Road
is not among the listed segments of Newfound Creek. Concentrations at this site exceeded the
instantaneous standard in 3 of 12 baseflow samples and 2 of 9 stormflow samples. The maximum
concentration recorded at this site is 1,800, measured on 1/7/1998 during a storm event. Given the land
uses reported by TVA upstream of this site, pasture and residential land are likely sources of elevated
concentrations.
In the lower half of the watershed, NCDENR monitors two sites for fecal coliform. The site at Highway
63 captures approximately two thirds of the total watershed area and is located in a more developed area
than the upstream site at McPeters Road. Excursions of the instantaneous standard occurred in 7 of 10
baseflow samples and 6 of 9 stormflow samples. The NCDENR site furthest downstream is located near
the mouth of Newfound Creek. This site exceeded the instantaneous standard in 7 of 12 baseflow
samples and 10 of 11 stormflow samples. At the two downstream sites, the frequency of excursions and
Newfound Creek TMDL – Final Version Submitted to EPA January 2005

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the total bacterial count were higher during storm events. At McPeters Road, the frequency of
exceedances was approximately the same under wet and dry conditions.
1
10
100
1000
10000
100000
1996 1997 1998 1999 2000 2001 2002 2003
Date
FC

(
#
/
1
0
0
m
L
)
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Fl
o
w

(
c
f
s
)
SR1641 Observed FC
Highw ay 63 Observed FC
McPeters Rd. Observed FC
Estimated Flow
Observed Flow

Figure 11. Newfound Creek Monitoring Data at Three NCDENR Sites
Table 10 summarizes the land use percentages, animal populations, and septic system densities upstream
of each NCDENR monitoring site. Given that the McPeters Road Site has a relatively low maximum
fecal coliform concentration (1,800) and low densities of animal operations and pastureland, washoff
from animal operations are probably not the main source of fecal contamination at this site although direct
deposition from animals with access to streams may be. However, relative to the other watersheds, the
septic system density is also low. The Highway 63 and Jenkins Valley Road sites have fecal coliform
concentrations observed in the tens of thousands. Pastureland comprises more than 30 percent of the total
watershed area in each watershed, and the animal densities are approximately 10 times higher than that in
the McPeters Road watershed. The Jenkins Valley Road watershed has the highest septic system density,
but relatively few low-flow exceedances of the fecal coliform instantaneous standard.
Table 10. Summary of Pollutant Loadings Upstream of the NCDENR Monitoring Sites
Source McPeters Road Highway 63 Jenkins Valley Road
Septic System Density
(#/sq. mi.)
11.2 12.5 20.0
Large Animal Densitya
(#/sq. mi.)
9.3 103.1 81.3
Percent Forest Land 85.4 52.3 45.2
Percent Pasture Land 7.8 32.3 34.6
Percent Residential Land 5.5 34.6 14.7
aLarge animal density is the total number of beef cattle, dairy cows, swine, and horses per square mile.
1
Newfound Creek TMDL – Final Version Submitted to EPA January 2005

20
The USGS samples show a similar trend. At the upstream Newfound Creek sites (Haylandy Road and
Browntown Road), stormflow samples were greater than baseflow samples by a factor of 1.3 to 2.2. At
the downstream sites, concentrations were 20 to 25 times higher during stormflow conditions compared to
baseflow. Total bacterial counts were higher during baseflow at the upstream sites and during stormflow
at the downstream sites.
The BCSWCD sites are located in the upper portion of the watershed. The two sites on Morgan Branch
exceeded the instantaneous standard on each sampling event. Four sites are located on Round Hill
Branch; each exceeded the instantaneous standard in at least 70 percent of observations. Four sites are
located on Newfound Creek. The furthest upstream site (1A) exceeded the instantaneous standard in 60
percent of observations; 94 percent of observations at the next site (1B) exceeded the standard. A similar
pattern occurs at sites 2A and 2B, where the frequency of excursions are is 88 percent and 100 percent,
respectively.
2.1.3 Point Source Fecal Coliform Contributions
There are no point source dischargers in the Newfound Creek Watershed according to the USEPA Water
Discharge Permits Compliance System database.

Newfound Creek TMDL – Final Version Submitted to EPA January 2005

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3 Technical Approach
Given the results of the initial data analysis and schedule 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 is presented in Section 4.
3.1 TMDL ENDPOINTS
The achievement of the TMDL objectives requires 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 endpoints for the determination of the fecal coliform TMDL for Newfound
Creek.
3.2 LOAD-DURATION CURVES FOR 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 Load-Duration Curve
Method (Stiles 2002, Cleland 2002) was used to estimate fecal coliform impairment. 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 first 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. Flows in
Newfound Creek were based on USGS observations at Gage 03451690 from December 2000 to
September 2004. Flows prior to December 2000 were estimated based on regression with flows at two
other USGS gages (Section 1.3).
Once the relative rankings were calculated for flow in Newfound Creek, monitoring data were matched
by date to compare observed water quality to the flow regime during which it was collected. This type of
analysis can help define the flow regime during which exceedances occur and also pinpoint the source of
the impairment. Criterion excursions that occur only during low-flow events are likely caused by
continuous or point source discharges, which are generally diluted during storm events. Criterion
excursions 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.
In Figure 12 through Figure 17, the flow-duration water quality analysis is presented for the three
NCDENR monitoring stations on Newfound Creek. One USGS observation at Jenkins Valley Road was
used so that two additional geometric means could be calculated. All stations show excursions of the
instantaneous fecal coliform water quality standard (400 cfu/100 mL) during all flow regimes. However,
a lower percentage of excursions occurs during low flow conditions, and the magnitudes of the excursions
are much lower compared to typical, transitional, and high flow conditions. The data suggest that both
storm-event runoff and low-flow sources, such as illicit discharges or septic systems, contribute to high
fecal coliform loading in Newfound Creek, but that storm driven events drive concentrations significantly
Newfound Creek TMDL – Final Version Submitted to EPA January 2005

22
higher. Concentrations greater than 1,000/100 mL were only measured at flow duration intervals less
than 55 percent, and concentrations greater than 10,000/100 mL were only measured at flow duration
intervals less than 0.8 percent.

Newfound Creek at Jenkins Valley Road
WQ Duration Curve (NCDWQ and USGS)
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
,

c
f
u
/
1
0
0
m
L
NCDENR
USGS
WQ Standard
Geo mean
Low flowsTypical
High Transition
DroughtFlood

Figure 12. Flow-Duration Curve for NCDENR and USGS Fecal Coliform Data for Newfound Creek
at Jenkins Valley Road (1/27/96 through 6/20/03)

Newfound Creek TMDL – Final Version Submitted to EPA January 2005

23
Newfound Creek at New Leicester/Highway 63
WQ Duration Curve (NCDWQ)
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
,

c
f
u
/
1
0
0
m
L
NCDENR
WQ Standard
Geo mean
Low flowsTypical
High Transition
DroughtFlood

Figure 13. Flow-Duration Curve for NCDENR Fecal Coliform Data for Newfound Creek at
Highway 63 (11/25/96 through 6/20/03)
Newfound Creek at McPeters Road
WQ Duration Curve (NCDWQ)
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
NCDENR
WQ Standard
Geo mean
Low flowsTypical
High Transition
DroughtFlood

Figure 14. Flow-Duration Curve for NCDENR Fecal Coliform Data for Newfound Creek at McPeters
Road (12/1/96 through 6/1/99)
Newfound Creek TMDL – Final Version Submitted to EPA January 2005

24
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
1E+10
1E+11
1E+12
1E+13
1E+14
1E+15
1E+16
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent of Days Flow is Exceeded
Fe
c
a
l

C
o
l
i
f
o
r
m

L
o
a
d

(
m
i
l
l
i
o
n
s

C
F
U
s
/
d
)
Limit Curve Observed

Figure 15. Load-Duration Analysis for NCDENR and USGS Fecal Coliform Data for Newfound
Creek at Jenkins Valley Road (1/27/96 through 6/20/03)
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
1E+10
1E+11
1E+12
1E+13
1E+14
1E+15
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent of Days Flow is Exceeded
Limit Curve Observed

Figure 16. Load-Duration Analysis for NCDENR Fecal Coliform Data for Newfound Creek at
Highway 63 (11/25/96 through 6/20/03)
Newfound Creek TMDL – Final Version Submitted to EPA January 2005

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1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
1E+10
1E+11
1E+12
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent of Days Flow is Exceeded
Fe
c
a
l

C
o
l
i
f
o
r
m

L
o
a
d

(
m
i
l
l
i
o
n
s

C
F
U
s
/
d
)
Limit Curve Observed

Figure 17. Load-Duration Analysis for NCDENR Fecal Coliform Data for Newfound Creek at
McPeters Road (12/1/96 through 6/1/99)

3.3 DETERMINATION OF EXISTING FECAL COLIFORM LOAD AND
ASSIMILATIVE CAPACITY
The fecal coliform assessment uses the Load-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.
3.3.1 Instantaneous (20 Percent) Criterion
The water quality criterion for instantaneous fecal coliform concentrations allows up to 20 percent of
samples within a 30-day period to exceed the target. The regulations clearly recognize that some
excursions of the 200 CFU/100 mL target are expected to occur during washoff events. This frequency
component needs to be taken into account when determining the assimilative capacity.
In some past applications, NCDWQ has used an ad hoc approach to the analysis of the difference between
existing load and assimilative capacity. This approach involved fitting a regression line through those
observations that were above the criterion limit curve and associated with the 10th through 95th percentile
of the flow distribution. Based on guidance from EPA Region 4 and NCDENR, data collected during
extreme drought conditions ( > 95th percentile) and floods (< 10th percentile) were excluded from the
reduction analysis. Then, the natural log of the coliform loads exceeding the criterion 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. The existing loading was then compared to the allowable loading
Newfound Creek TMDL – Final Version Submitted to EPA January 2005

26
(with a margin of safety), and the difference used to establish needed reductions. Because the regression
line goes through the center of the distribution of points above the criterion limit curve, it allows a
fraction of the observations to exceed the criterion; however, this fraction is not explicitly tied to the 20
percent frequency of allowable excursions specified in the criterion.
For this TMDL, a more rigorous quantitative approach is used. The essence of this approach is as
follows:
• Establish a regression model to predict existing load as a function of flow percentage.
• Develop a prediction confidence interval on the regression line, with the confidence interval set at
a level that reflects the allowed 20 percent frequency of excursions.
• Calculate a reduced criterion limit curve at 90 percent of the criterion concentration, thus
incorporating a 10 percent margin of safety.
• Evaluate needed reductions based on the maximum difference between the prediction confidence
interval and the reduced criterion limit curve, incorporating a margin of safety, between the 10th
and 95th percentile flows.
The confidence interval is based on the point prediction interval about the regression line. That is, it
reflects the range of expected values for individual observations at a given flow frequency, and
incorporates both the uncertainty in the regression line and the natural variability of individual points
about the regression line. In theory, the upper 60th percentile confidence interval is just sufficient to meet
the criterion (20 percent of observations are expected to fall in both the high and low tails of the
distribution). However, the TMDL also requires a Margin of Safety. This is achieved by evaluating
needed reductions in relation to the criterion limit curve reduced by 10 percent (that is, evaluated at 360
rather than 400 CFU/100 mL). The Margin of Safety is thus assigned explicitly through a 10 percent
reduction in the criterion.
Complete details of the methodology for establishing the regression line and prediction confidence
interval are presented in Appendix B. A comparison of regression methods at Jenkins Valley Road
showed that the best fit was obtained with a log-linear regression (adjusted R2 = 65 percent), yielding a
model of the following form:
( )FractionFlowdCFUinLoadColiformLn⋅−=614.404.28/,
where flow fraction is the percentile of the flow expressed as a fraction.
Application of the regression equation and its upper 60th percentile prediction interval at Jenkins Valley
Road is shown in Figure 18. Comparison of the upper 60th percentile prediction interval with the reduced
limit curve shows that reductions are needed across all flow intervals, with the highest reduction (92.9
percent) needed during high flow conditions.

Newfound Creek TMDL – Final Version Submitted to EPA January 2005

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1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
1E+10
1E+11
1E+12
1E+13
1E+14
1E+15
1E+16
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent of Days Flow is Exceeded
Fe
c
a
l

C
o
l
i
f
o
r
m

L
o
a
d

(
m
i
l
l
i
o
n
s

C
F
U
s
/
d
)
Reduced Limit Curve Observed Regression 60% Upper Prediction Interval

Figure 18. Regression Analysis of the Instantaneous Fecal Coliform Load-Duration Curve,
Jenkins Valley Road
Newfound Creek TMDL – Final Version Submitted to EPA January 2005

28
Figure 19 shows the regression analysis at Highway 63. The regression line through this data set has an
adjusted R2 of 50 percent:

( )FractionFlowdCFUinLoadColiformLn⋅−=424.304.27/

At Highway 63 reductions are required at all flow intervals with the highest reductions needed at very low
flows (92.8 percent reduction at flow interval 100 percent) and at moderate flows (91.5 percent reduction
at flow interval 14.8 percent).

1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
1E+10
1E+11
1E+12
1E+13
1E+14
1E+15
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent of Days Flow is Exceeded
Reduced Limit Curve Observed Regression 60% Upper Prediction Interval

Figure 19. Regression Analysis of the Instantaneous Fecal Coliform Load-Duration Curve,
Highway 63
At McPeters Road, fecal coliform load is slightly dependent upon flow with an adjusted R2 of minus 1
percent. The estimated load and upper 60th percentile prediction interval are highly dependent on the
mean.
( )FractionFlowdCFUinLoadColiformLn⋅−=664.001.22/
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Figure 20 shows the analysis for observations at McPeters Road. The mean load is 5.21x109 CFUs/d. At
flow intervals less than 21.7 percent, no reduction is required. The highest reduction (89.3 percent) is
required under extreme dry conditions.

1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
1E+10
1E+11
1E+12
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent of Days Flow is Exceeded
Fe
c
a
l

C
o
l
i
f
o
r
m

L
o
a
d

(
m
i
l
l
i
o
n
s

C
F
U
s
/
d
)
Reduced Limit Curve Observed Regression 60% Upper Prediction Interval

Figure 20. Regression Analysis of the Instantaneous Fecal Coliform Load-Duration Curve,
McPeters Road
Each of the three stations have greater than 20 percent of observations exceeding the reduced limit curve:
24 percent of observations exceed the curve at McPeters Road, 77 percent exceed at Highway 63, and 77
percent exceed at Jenkins Valley Road.
Table 11 through Table 13 summarize the reduction requirements at each station under six ranges of flow.
Critical percentiles are the values within the flow range at which the ratio of the 60th percentile (60le)
prediction limit to target load is greatest. The flow column gives the flow corresponding to the critical
percentile. The target load is the value of 90 percent of the instantaneous criterion limit curve at the
specified flow and percentile, thus incorporating a 10 percent margin of safety. The 60le prediction limit
is the upper prediction interval about the regression line at the 60 percent confidence level. The reduction
required is calculated as (60le Prediction Limit – Target Load)/(60le Prediction Limit). As discussed
above, only calculations between the 10th and 95th percentile are used in the estimation of the TMDL.
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Table 11. Fecal Coliform Target Load and Reduction Requirements Calculated Using the Load-
Duration Curve Approach at Jenkins Valley Road
Flow Range
Critical
Percentile Flow (cfs)
Target Load
(CFU/d)
60le Prediction
Limit (CFU/d)
Reduction
Required
0-10%
(High Flows) 7.34% 33.0 2.91 x1011 4.09 x1012 92.89%
10-40% (Moist
Conditions) 10.06% 29.6 2.61 x1011 3.62 x1012 92.78%
40-60% (Mid-
Range Flows) 40.00% 14.0 1.23 x1011 1.00 x1012 87.70%
60-90%
(Dry Conditions) 60.00% 9.7 8.54x1010 4.46x1011 80.86%
90-95%
(Low Flows) 94.73% 4.1 3.61 x1010 1.17 x1011 69.05%
95-100%
(Drought) 100.00% 1.8 1.59 x1010 9.58 x1010 83.46%

Table 12. Fecal Coliform Target Load and Reduction Requirements Calculated Using the Load-
Duration Curve Approach at Highway 63
Flow Range
Critical
Percentile Flow (cfs)
Target Load
(CFU/d)
60le Prediction
Limit (CFU/d)
Reduction
Required
0-10%
(High Flows) 9.56% 14.05 1.24 x1011 1.45 x1012 91.46%
10-40% (Moist
Conditions) 14.85% 11.70 1.03 x1011 1.22 x1012 91.55%
40-60% (Mid-
Range Flows) 40.00% 6.55 5.77 x1010 5.59 x1011 89.67%
60-90%
(Dry Conditions) 60.00% 4.54 4.00 x1010 3.12 x1011 87.17%
90-95%
(Low Flows) 94.73% 1.92 1.69 x1010 1.19 x1011 85.83%
95-100%
(Drought) 100.00% 0.84 7.42 x109 1.04 x1011 92.84%

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Table 13. Fecal Coliform Target Load and Reduction Requirements Calculated Using the Load-
Duration Curve Approach at McPeters Road
Flow Range
Critical
Percentile Flow (cfs)
Target Load
(CFU/d)
60le Prediction
Limit (CFU/d)
Reduction
Required
0-10%
(High Flows) NA1 NA1 NA1 NA1 NA1
10-40% (Moist
Conditions) 40.00% 0.86 7.57x109 1.02 x1010 25.92%
40-60% (Mid-
Range Flows) 60.00% 0.59 5.25 x109 1.10 x1010 52.20%
60-90%
(Dry Conditions) 90.00% 0.31 2.70 x109 1.26 x1010 78.59%
90-95%
(Low Flows) 95.00% 0.25 2.21 x109 1.29 x1010 82.94%
95-100%
(Drought) 100.00% 0.11 9.73 x108 1.33 x1010 92.68%
1 No reduction needed at flow durations less than 21.7 percent.

Figure 21 shows the reductions needed at each monitoring station to meet the instantaneous fecal coliform
standard. The necessary reductions at McPeters Road are inversely proportional to flow with the greatest
reduction (92.7 percent) needed during drought conditions. Downstream at Highway 63, required
reductions are greater than 85.8 percent under each flow regime and are approximately the same under
extreme high and low flow conditions (approximately 92 percent). At Jenkins Valley Road, reductions
greater than 69 percent are needed under each flow regime and at very high flows, reductions of 92.9
percent are required to meet the instantaneous standard.
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
5-10% 10-40% 40-60% 60-90% 90-95% 95-100%
Flow Duration Interval
Re
d
u
c
t
i
o
n

R
e
q
u
i
r
e
d

t
o

M
e
e
t

t
h
e

In
s
t
a
n
t
a
n
e
o
u
s

F
e
c
a
l

C
o
l
i
f
o
r
m

S
t
a
n
d
a
r
d
Jenkins Valley Highway 63 McPeters
LowHigh

Figure 21. Reductions Needed in Fecal Coliform Loading Along Newfound Creek to
Meet the Instantaneous Standard
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3.3.2 Geometric Mean Criterion
NCDENR conducted special assessments at Highway 63 and at Jenkins Valley Road during the summer
of 2003 to calculate 5-day geometric means at these stations. Loads were calculated by averaging the
flows observed on each of the five days. The target load is calculated for each flow duration interval
based on a fecal coliform concentration of 180/100 mL (10 percent Margin of Safety).
Figure 22 shows the geometric mean loads calculated for Newfound Creek at Jenkins Valley Road. Five
geometric means were calculated (2603, 3385, 993, 1180, and 1704); all exceed the standard of 200/100
mL. The geometric mean of the observed loads compared to the geometric mean of the target load shows
that a reduction of 89.9 percent is required to meet the standard at this station.
1.0E+08
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
)
NCDENR Special Study and USGS FC Load Limit with MOS

Figure 22. Geometric Mean Fecal Coliform Load-Duration Curves for Newfound Creek at Jenkins
Valley Road
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Figure 23 shows the geometric mean loads calculated at Highway 63, where three geometric means were
calculated (5844, 1239, and 1810/100 mL). A reduction of 92.4 percent is required to meet the geometric
mean standard at this station.
1.0E+08
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 (%)
NCDWQ Special Study FC Load Limit with MOS

Figure 23. Geometric Mean Fecal Coliform Load-Duration Curves for Newfound Creek at
Highway 63
At both stations, the reduction under the instantaneous standard is greater than under the geometric mean
standard. Jenkins Valley Road requires the greatest reduction under the instantaneous standard (92.9
percent).
3.3.3 Source Assessment
The load-duration curves developed in this section provide guidance in the determination of the pollutant
sources that are likely to be 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 continuously discharging sources, such as failing septic systems. Nonpoint sources such as
stormwater runoff are likely to be the main focus of the inventory in this case.
The TVA performed a detailed source assessment for nutrients and sediment in the Newfound Creek
Watershed. As part of the assessment, TVA developed a spreadsheet to estimate loading from
potential sources in the watershed. Rural landuse loading estimates are based on the
Universal Soil Loss Equation (USLE). Urban loadings were developed based on runoff
volumes and Event Mean Concentrations (EMCs). The land use characterization discussed
in Section 1.2 was used to determine the distribution of land use types in each watershed.
The source assessment was used as the basis of model development and analysis of TMDL
allocation options. A variety of information was used to characterize sources including
agricultural and land use information, GIS coverages, past TMDL studies, literature
sources, and discussion with local resource agency staff.
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3.3.3.1 Urban Nonpoint Source Loads
Urban loading rates were developed using a method described in the USEPA report Urban
Targeting and BMP Selection: An Information and Guidance Manual for State Nonpoint Source Program
Staff Engineers and Managers (EPA 1990). This method estimates runoff from various land use
types depending on the impervious fraction of each. The annual runoff is then multiplied
by an EMC to develop an annual loading rate for each landuse. The TVA loading tool
developed for this purpose was modified to include fecal coliform loads for the sources identified by
TVA. The EMCs for fecal coliform were based on runoff characteristics of different land use
types measured as part of a detailed stormwater characterization effort (USGS, 1999). In
addition, loadings from septic systems and wildlife were added to complete the source characterization.
3.3.3.2 Septic Systems
Residential septic systems treat human waste using a collection system that discharges
liquid waste into the soil through a series of distribution lines that comprise the drain field.
Fecal coliform bacteria naturally die-off as the effluent percolates through the soil to the
groundwater. These systems effectively remove fecal coliform bacteria when properly
installed and maintained. A septic system failure occurs when there is a discharge of waste
to the soil surface where it is available for washoff into surface waters. Failing septic
systems can deliver high bacteria loads to surface waters, depending on the proximity of the
discharge to a stream and the timing of rainfall events. Septic system failures typically
occur in older systems that are not adequately maintained with periodic sewage pump-outs.
The Buncombe County Health Department typically suggests a failure rate of 10 percent. However, the
TVA source assessment indicated that a majority of the systems are classified as suspect in some way
(location on small lots, steep slopes, rock outcroppings, or in close proximity to streams), so it is likely
that the failure rate is much higher. The TVA source assessment estimated that approximately
668 septic systems in the watershed appeared to be suspect or failing to some extent. Of the
systems inventoried, one has a distinctive moisture pattern indicative of ponding, and 110 have a
suspicious moisture pattern but no visible drain field. These septic systems were assumed to be failing
for the purpose of determining an annual load. Another 16 have no apparent plume and appear to be
properly functioning. While the 560 remaining systems are suspect due to their location, it is unlikely
that all were completely failing. For the purpose of the annual loading contributions, it was assumed that
50 percent were failing.
A fecal coliform bacteria concentration of 8.3x106 cfu/100mL and a septic system waste flow
of 70 gallons/person/day was used to estimate the contribution from failing septic systems
to surface waters (Thomann and Mueller, 1987). Houses considered to have a normally
functioning septic system were assumed to have a negligible contribution of fecal bacteria
to surface waters.
3.3.3.3 Agriculture
Bacteria produced by livestock can be deposited on the land, directly deposited in the
stream (as is common when grazing animals have stream access), manually applied to
cropland and other agricultural lands as fertilizer, or contributed to surface waters through
illicit discharges from animal confinement areas. Estimates for loading from livestock
animals are based on the TVA survey of animal operations, manure production by animal
type, and the fecal content of different livestock manure. The results of these calculations
are presented in Table 14.
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Table 14. Livestock Fecal Coliform Bacteria Production Rates
Livestock Species
Daily Production
(cfu/animal/day) Source
Beef cattle 4.46 x 1010 ASAE 1998
Dairy cattle 3.90 x 1010 ASAE 1998
Chickens 6.75 x 107 ASAE 1998
Turkeys 9.30 x 107 ASAE 1998
Hogs/Pigs 1.08 x 1010 ASAE 1998

Bacteria deposited on the land, either directly or through manure application, are available for washoff
into surface waters during rainfall events. Grazing animals, such as beef and dairy cattle, typically spend
portions of the day confined to loafing lots, grazing on pasturelands, and watering in nearby streams. The
percentage of time spent in each area effects the relative contribution of bacteria loads to the stream.
These factors were taken into consideration to estimate the fraction of the total fecal coliform load
produced by livestock that would be delivered to the stream.
The estimate for loading from animal operations that were not directly adjacent to tributaries of
Newfound Creek was set to 10 percent of the produced load. Loading from animal operations adjacent to
the streams was only reduced by 75 percent to account for the lower potential for transport losses and
decay.
3.3.3.4 Wildlife
Wildlife species in the watershed were identified through discussion with the NC Wildlife Commission.
The predominant species include geese, deer, beaver, and raccoon. The population of each wildlife
species was estimated using the population density per square mile of habitat area and estimates for the
area of suitable habitat in the watershed.
As with grazing livestock, wildlife deposit fecal matter on the land and directly to surface waters. The
percentage of fecal coliform bacteria that was directly deposited to surface waters was estimated based on
the habitat of each species. The remaining fecal coliform load was applied to the upland land uses,
according to the total area of each land use within established habitat areas. The typical fecal coliform
density for each wildlife species was used to calculate fecal coliform bacteria loads (Table 15).
Table 15. Fecal Coliform Bacteria Production Rates For Wildlife Species
Wildlife Species
Daily Production
(cfu/animal/day) Source
Ducks 7.35 x 109 ASAE 1998
Geese 7.99 x 108 ASAE 1998
Deer 3.47 x 108 Yagow 1999
Raccoon 5.0 x 109 Yagow 1999

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3.3.3.5 Total Loads
The results of the watershed loading estimates are shown in Figure 24. The contribution of fecal coliform
to Newfound Creek is dominated by loadings from animal operations, which constitute 98 percent of the
estimated load. These are grouped with other agricultural sources in Figure 24, but the contributions from
non-manured crops (exclusive of wildlife) are estimated to be minimal. Septic systems also appear to
play a significant role in fecal coliform impairments contributing 1.3 percent of the estimated total load.
This combination of sources helps to explain the impairment of Newfound Creek under most flow
conditions.
While these estimates are based on a number of assumptions, they are suitable for a general assessment of
the nonpoint sources in the watershed. Wherever possible, detailed information was used to quantify the
potential sources in the watershed. It should be noted, however, that incorporation of best management
practices (BMPs) is not included in the source estimates. Recent adoption of agricultural BMPs may play
a role in the reduction of high fecal coliform loads under high flow events.
The aggregate contributions by subwatershed were calculated to help provide some insight into the areas
which potentially contribute the highest fecal coliform loadings and which may provide reduction
opportunities (Figure 25).

Estimated Fecal Coliform Loading by Source
for Newfound Creek Watershed
1.0E+00
1.0E+01
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
1.0E+07
1.0E+08
1.0E+09
1.0E+10
1.0E+11
Urban Runoff Septic Agriculture Wildlife
FC

(
m
i
l
l
i
o
n

c
o
u
n
t
s

p
e
r

Y
e
a
r
)

Figure 24. Fecal Coliform Loading by Source in the Newfound Creek Watershed

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37
Estimated Fecal Coliform Loading by Watershed
for Newfound Creek Watershed
1.0E+00
1.0E+01
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
1.0E+07
ewfound Creek (He
adw
ate
Morga
n
Branch
ewfou
nd Cr
e
ek
Round
Hill B
r
a
nch
New
f
o
u
n
d

C
r
e
e
k
nname
d
Tr
ewf
ound C
reek
Gouche
s Bran
ch
ewfound Creek
Slude
r Bran
ch
ewfou
nd C
r
e
ek
Parke
r

B
r
a
n
c
h
Upper D
ix Cr
e
e
Unna
med Trib Dix
Cr
ee
ewfound C
reek (
Mout

Figure 25. Fecal Coliform Loading by Subwatershed in the Newfound Creek Watershed
At McPeters Road in the rural, upstream section of the watershed, excursions of the instantaneous
standard have a relatively low magnitude (maximum observed 1800/100 mL) and occur during low to
medium flows. Exceedances at this station are likely due to slow, continuous sources such as septic
systems. Pastureland adjacent to the stream may also contribute loads during rain events.
At Highway 63, the watershed is more developed with pasture and single-family residential lands.
Excursions occur with greater frequency and higher magnitude during high flow conditions. The
maximum fecal coliform concentration observed at Highway 63 is 57,000/100 mL. Three observations
collected when the flow duration interval was less than 1 percent were all over 49,000/100 mL.
Concentrations of this magnitude that occur during high flow events are likely due to runoff from animal
operations.
At Jenkins Valley Road, the maximum concentration observed was 65,000, which occurred at a flow
duration interval of less than 1 percent. The majority of excursions occur during wet events and are likely
due to runoff from animal operations and residential land use.
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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 Total Maximum Daily Load (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 Class C waters). 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

For Newfound Creek, there are no permitted point sources. Thus the TMDL contains no WLAs.
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, 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 criterion of 200 cfu/100 mL will be
considered.
4.3 CRITICAL CONDITIONS
The Load-Duration Curve approach addresses the load reductions required during all flow regimes.
Unlike a steady state analysis, it does not depend on the identification of critical conditions to determine
allocations. The load-duration analysis in Section 3.3, however, indicates that excursions of the criterion
are primarily associated with higher flows with significant surface runoff. Therefore, implementation of
the TMDL should focus on storm washoff events as a critical condition.
As shown in Table 11 in Section 3.3.1, the maximum reduction in existing loads (within the 10-95% flow
range) is required at a flow of 29.6 cfs at Jenkins Valley Road. At this flow, the assimilative capacity (the
maximum load that just meets the instantaneous limit of 400 CFU/100 mL) is 2.61x1011 CFU/d.
4.4 SEASONAL VARIATIONS
Seasonal variation is considered in the development of the TMDLs because the allocation applies to all
seasons. In Newfound Creek, exceedances occur during all months. For example in Figure 26,
exceedances follow a similar pattern during winter and summer months at Jenkins Valley Road.
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40
Newfound Creek at Jenkins Valley Road
WQ Duration Curve (NCDWQ and USGS)
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
,

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

Figure 26. Flow Duration Curve of NCDENR Fecal Coliform Data for Newfound Creek at Jenkins
Valley Road (12/1/96 through 6/1/99) with Summer and Winter Observations
Distinguished
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.
At the critical flow of 29.6 cfs at Jenkins Valley Road, the assimilative capacity is 2.90x1011 CFU/d,
while the target load is 2.61x1011 CFU/d – a 10 percent reduction. Therefore, the explicit MOS is
2.60x1010 CFU/d at the critical flow of 33 cfs.
4.6 LOAD ALLOCATION
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 using the water quality standards and a 10 percent
MOS. A summary of the estimated reductions required to meet the TMDL target is presented in Table
16. It can be seen that the instantaneous target is the most stringent for Newfound Creek at each station.
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Table 16. Summary of Estimated Reductions
Stream Pollutant Target Reduction Required
Newfound Creek at
Jenkins Valley Road
Fecal coliform
(Instantaneous Limit) <360 cfu/100 mL 92.8
Newfound Creek at
Highway 63
Fecal coliform
(Instantaneous Limit) <360 cfu/100 mL 91.6
Newfound Creek at
McPeters Road
Fecal coliform
(Instantaneous Limit) <360 cfu/100 mL 82.9
Note: Maximum reduction calculated between 10th and 95th percentile flows
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. The reductions required for Newfound Creek were highest at
Jenkins Valley Road. The highest reduction requirements will be selected to provide an added margin of
safety to the TMDL. To achieve the specified TMDL targets, significant reductions were required. These
are summarized in Table 17.
Table 17. TMDL Reductions for Fecal Coliform
Stream Pollutant Target
Target
Load
(#/day)
Margin of
Safety
(#/day)
Existing
Load (#/day)
Reduction
Required
Newfound
Creek
Fecal coliform
(Instantaneous
Limit)
<360 cfu/100 mL 2.61x1011 2.60x1010 3.62.x1012 92.8%

In the case of Newfound Creek, all of the fecal coliform loading is due to nonpoint sources. Thus the
TMDL will be allocated in terms of nonpoint source (LA) loadings only. TMDL allocations are
summarized in Table 18.
Table 18. Newfound Creek TMDL Components
Segment Pollutant Existing WLA1 LA MOS2 TMDL
Newfound
Creek
Fecal coliform
(counts/day) 4.09 x1012 0.00 2.61x1011 2.60x1010 2.90x1011

Source analysis (Section 3.3.3.5) suggests that the vast majority of the existing load is due to domestic
animals. Therefore, it appears that needed reductions should be sought primarily from this sector.
However, it will also be important to identify failing septic systems, as loads of human waste present a
greater health risk.
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5 Report Summary
This report presents the development of a TMDL for fecal coliform impairment of Newfound Creek near
Asheville, North Carolina. Newfound Creek was placed on the North Carolina 2002 list of impaired
waters (the 303(d) list) for 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. A review of fecal coliform
data indicates that rural source contributions, such as animal operations, septic systems, and runoff from
farms and residential developments, are a significant source of much of the fecal coliform impairment.
These results were used to derive the allocations required by the TMDL. The specified reductions can be
achieved with an increased emphasis on BMPs for animal operations, protection of riparian buffers, and
identification and repair of aging or failing septic systems.
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6 TMDL Implementation Plan
The TMDL analysis was performed using the best data available to specify the fecal coliform 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.
The preliminary source assessment suggests that large domesticated animals (particularly cattle) may be
the major source of fecal coliform loading to Newfound Creek. Therefore, reductions for fecal coliform
should first be sought through installation and maintenance of agricultural BMPs for farm animals. Key
efforts could include exclusion of animals from streams and maintenance of adequate riparian buffers.
Although estimated to contribute less than two percent of the total load, identification and repair of aging
or failing septic systems is also advisable for the protection of human health. Implementation could also
target storm-driven sources such as runoff from residential areas and crop land.
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7 Stream Monitoring
Fecal coliform monitoring should continue at Jenkins Valley Road, Highway 63, and McPeters Road
monitoring sites. The continued monitoring of fecal coliform concentrations will allow for the evaluation
of progress towards the goal of reaching water quality standards. NCDENR does not have ambient
monitoring stations at these sites. Therefore, we recommend the establishment of an ambient monitoring
site at Jenkins Valley Road. Additional monitoring could focus on fecal coliform source assessment in
the watershed; this would further aid in the evaluation of the progress towards meeting the water quality
standard.
BCSWCD will continue monthly monitoring of their ten water quality sites, excluding sites 5A and 5B
which will not be monitored after July 29th, 2004. USGS has no scheduled events for the five fecal
coliform sites.

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8 Future Efforts
The Buncombe County Soil and Water Conservation District offers grant money through the Clean Water
Management Trust Fund program to assist residents interested in using BMPs to reduce pollutant loads
from their land. Existing installations include livestock fences, constructed wetlands, streambank
stabilization, and waste treatment lagoons.
Septic systems must be properly maintained and inspected periodically. Maintenance records submitted
to Buncombe County may help identify systems in need of attention. Community outreach through
advertising should target owners of septic systems who are unaware of maintenance guidelines, such as
pumping every five years.
Other potential mechanisms for reduction of fecal coliform include local regulations or ordinances related
to zoning, land use, 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 on November 15th, 2004 (see Appendix C). DWQ will electronically distribute the draft
TMDL and public comment information to known interested parties. The TMDL is also be available
from the Division of Water Quality’s website at http://h2o.enr.state.nc.us/tmdl/ during the comment
period. The public notice period lasted 30 days and ended on December 15, 2004.
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53
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:
Adugna Kebede, Modeler
e-mail: [e-mail]
Michelle Woolfolk, Supervisor
e-mail: [e-mail]

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11 References
ASAE Standards, 45th Edition. 1998. Manure production and characteristics. St. Joseph, MI.
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.
NCDENR. 2003. North Carolina Water Quality Assessment and Impaired Waters List (2002 Integrated
305(b) and 303(d) Report) Final, February 2003. Prepared by the North Carolina Department of
Environment and Natural Resources, Division of Water Quality.
Stiles, T.C. 2002. Incorporating hydrology in determining TMDL endpoints and allocations.
Proceedings from the WEF National TMDL Science and Policy 2002 Conference.
Thomann, R.V. and J.A. Mueller. 1987. Principles of Surface Water Quality Modeling and Control.
Harper Collins Publishers.
TVA. 2002. Newfound Creek Watershed Nonpoint Source Pollution Inventory and Pollutant Load
Estimates. Prepared for Buncombe Soil and Water Conservation District, Asheville, NC. Prepared by
Tennessee Valley Authority, November 2002.
EPA. 1990. Urban Targeting and BMP Selection: An Information and Guidance Manual for State
Nonpoint Source Program Staff Engineers and Managers. Prepared for the U.S. Environmental
Protection Agency, Region V, Water Division and Office of Water Regulations and Standards, Office of
Water Enforcement and Permits.
USEPA. 1991. Guidance for Water Quality-Based Decisions: The TMDL Process. U. S. Environmental
Protection Agency, Assessment and Watershed Protection Division, Washington, DC.
USEPA. 1998. Federal Advisory Committee (FACA). Draft Final TMDL Federal Advisory Committee
Report.
USEPA. 1999. Protocol for Developing Nutrient TMDLs. 1st ed. EPA 841-B-99-007. U. S.
Environmental Protection Agency; Assessment and Watershed Protection Division.
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. Federal Register, 65:43586-43670.
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.
Yagow. 1999. Unpublished monitoring data. Mountain Run TMDL Study.
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A-1
Appendix A Water Quality Sampling Data
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A-2
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A-3
Table A-1. NCDENR Ambient Monitoring Data for Newfound Creek at
Jenkins Valley Road (1996-1999)
Date Flow (cfs)1 Flow Interval
Observed FC
(#/100 mL)
1/27/1996 199.0 0.00 430
10/22/1996 7.3 0.76 760
11/25/1996 13.3 0.42 940
12/16/1996 19.4 0.25 220
4/7/1997 29.2 0.11 1,700
5/28/1997 17.7 0.29 2,200
6/30/1997 13.1 0.43 3,200
9/8/1997 5.0 0.90 120
10/29/1997 11.3 0.52 500
1/7/1998 99.8 0.01 9,900
2/23/1998 43.0 0.04 9,500
3/9/1998 57.3 0.02 440
3/23/1998 35.5 0.06 430
4/28/1998 27.1 0.13 1,600
7/13/1998 7.3 0.77 20
9/1/1998 3.8 0.96 430
10/5/1998 4.1 0.95 370
11/5/1998 4.3 0.94 100
12/9/1998 6.6 0.81 210
1/15/1999 35.5 0.06 2,400
3/26/1999 18.1 0.27 880
5/18/1999 14.8 0.37 590
6/14/1999 7.9 0.73 460
1Flow estimated from nearby gages USGS 03453000 and USGS 03500240.

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A-4
Table A-2. NCDENR Special Study Monitoring Data for Newfound Creek at
Jenkins Valley Road (2003)
Date Flow (cfs) 1 Flow Interval
Observed FC
(#/100 mL)
4/14/2003 46.0 0.03 410
4/21/2003 29.0 0.11 3,300
4/28/2003 20.0 0.24 97
5/5/2003 95.0 0.01 14,000
5/6/2003 694.0 0.00 65,000
6/2/2003 18.0 0.28 350
6/3/2003 19.0 0.26 1,500
6/9/2003 20.0 0.24 1,100
6/10/2003 18.0 0.28 1,800
6/17/2003 21.0 0.22 2,200
6/20/2003 20.0 0.24 2,200
1Observed flow is from USGS Gage 03451690, Newfound Creek.

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A-5
Table A-3. NCDENR Ambient Monitoring Data for Newfound Creek
at Highway 63 (1996-1999)
Date Flow (cfs) 1 Flow Interval
Observed FC
(#/100 mL)
11/25/1996 6.2 0.42 1,500
12/16/1996 9.1 0.25 2,800
5/28/1997 8.3 0.29 2,000
6/30/1997 6.1 0.43 600
10/29/1997 5.3 0.52 250
1/7/1998 46.7 0.01 57,000
2/23/1998 20.1 0.04 7,000
3/9/1998 26.8 0.02 770
3/23/1998 16.6 0.06 140
4/28/1998 12.7 0.13 270
7/13/1998 3.4 0.77 260
9/1/1998 1.8 0.96 840
10/5/1998 1.9 0.95 790
11/5/1998 2.0 0.94 210
12/9/1998 3.1 0.81 320
1/15/1999 16.6 0.06 1,200
3/26/1999 8.4 0.27 3,300
5/18/1999 6.9 0.37 660
6/14/1999 3.7 0.73 950
1Flow estimated and scaled from nearby gages USGS 03453000 and USGS 03500240.

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A-6
Table A-4. NCDENR Special Study Monitoring Data for Newfound Creek
at Highway 63 (2003)
Date Flow (cfs) 1 Flow Interval
Observed FC
(#/100 mL)
4/14/2003 21.5 0.03 750
4/21/2003 13.6 0.11 7,000
4/28/2003 9.4 0.24 500
5/5/2003 44.4 0.01 49,000
5/6/2003 324.7 0.00 53,000
6/2/2003 8.4 0.28 210
6/3/2003 8.9 0.26 1,400
6/9/2003 9.4 0.24 2,000
6/10/2003 8.4 0.28 1,600
6/17/2003 9.8 0.22 3,100
6/20/2003 9.4 0.24 1,400
1Observed flow scaled from USGS Gage 03451690, Newfound Creek.

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A-7
Table A-5. NCDENR Ambient Monitoring Data for Newfound Creek at
McPeters Road (1996-1999)
Date Flow (cfs) 1 Flow Interval
Observed FC
(#/100 mL)
12/1/1996 4.9 0.01 39
1/1/1997 1.3 0.22 12
2/1/1997 1.3 0.21 53
4/1/1997 1.7 0.12 120
5/1/1997 2.0 0.08 50
6/1/1997 2.0 0.08 70
9/1/1997 0.3 0.87 360
10/1/1997 0.5 0.72 690
1/1/1998 0.7 0.55 1,800
2/1/1998 1.6 0.13 120
3/1/1998 1.6 0.14 20
4/1/1998 1.8 0.11 76
7/1/1998 0.6 0.56 94
9/1/1998 0.2 0.96 460
10/1/1998 0.3 0.94 160
11/1/1998 0.2 0.95 300
12/1/1998 0.3 0.92 68
1/1/1999 0.4 0.78 50
3/1/1999 1.5 0.16 620
5/1/1999 1.0 0.34 140
6/1/1999 0.6 0.63 600
1Flow estimated and scaled from nearby gages USGS 03453000 and USGS 03500240.

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A-8
Table A-6. USGS Monitoring Data for Stations on Newfound Creek
and Tributaries (1997, 2003)
Date Station Flow (cfs)1
Observed FC
(#/100 mL)
4/8/1997 01 36.00 2,700
5/28/2003 01 22.00 930
11/19/2003 01 195.00 24,000
5/28/2003 05 13.80 1,400
11/19/2003 05 88.40 29,000
5/28/2003 06 1.16 140
11/19/2003 06 15.00 6,000
5/28/2003 07 9.17 8,700
11/19/2003 07 51.10 11,000
5/28/2003 10 2.70 1,300
11/19/2003 10 13.50 2,900
1Flow measured at water quality station.

Table A-7. Buncombe County Monitoring Data for Stations on Newfound Creek
and Tributaries (2002-2004)
Date Site Flow (cfs)1,2 Observed FC (#/100 mL)
4/30/2002 1A 7.5 208
5/13/2002 1A 15 370
5/30/2002 1A 7.2 360
10/16/2002 1A 33 1,582
11/6/2002 1A 9.6 200
12/17/2002 1A 17 820
1/7/2003 1A 16 62
1/16/2003 1A 12 144
1/21/2003 1A 14 46
1/30/2003 1A 12 2,800
2/12/2003 1A 13 620
2/25/2003 1A 38 380
3/19/2003 1A 24 6,000
4/28/2003 1A 20 740
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A-9
Date Site Flow (cfs)1,2 Observed FC (#/100 mL)
6/12/2003 1A 21 138
7/2/2003 1A 75 3,200
7/24/2003 1A 18 230
8/6/2003 1A 28 455
8/20/2003 1A 14 720
9/3/2003 1A 19 525
9/15/2003 1A 14 505
10/1/2003 1A 13 260
10/15/2003 1A 14 445
11/5/2003 1A 15 4,700
11/19/2003 1A 590 3,800
12/10/2003 1A 39 2,900
12/17/2003 1A 30 333
2/18/2004 1A 24 207
3/9/2004 1A 17 5,000
3/24/2004 1A 17 4,400
4/7/2004 1A 16 4,750
4/20/2004 1A 22 1,513
5/3/2004 1A NA 1,692
5/19/2004 1A 16 3,000
6/16/2004 1A 34 2,500
7/14/2004 1A 17 600
7/29/2004 1A NA 1,160
4/30/2002 1B 7.5 2,800
5/13/2002 1B 15 5,300
5/30/2002 1B 7.2 3,500
10/16/2002 1B 33 2,200
11/6/2002 1B 9.6 5,500
12/17/2002 1B 17 580
1/7/2003 1B 16 16,533
1/16/2003 1B 12 210
1/21/2003 1B 14 5,550
1/30/2003 1B 12 200
2/12/2003 1B 13 760
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A-10
Date Site Flow (cfs)1,2 Observed FC (#/100 mL)
2/25/2003 1B 38 1,750
3/19/2003 1B 24 6,000
4/28/2003 1B 20 1,100
6/12/2003 1B 21 2,017
7/2/2003 1B 75 11,600
7/24/2003 1B 18 1,517
8/6/2003 1B 28 2,100
8/20/2003 1B 14 3,400
9/3/2003 1B 19 1,080
9/15/2003 1B 14 6,800
10/1/2003 1B 13 1,275
10/15/2003 1B 14 7,900
11/5/2003 1B 15 47,000
11/19/2003 1B 590 4,067
12/10/2003 1B 39 28,000
12/17/2003 1B 30 521
2/18/2004 1B 24 1,160
3/9/2004 1B 17 7,800
3/24/2004 1B 17 9,800
4/7/2004 1B 16 6,200
4/20/2004 1B 22 5,000
5/3/2004 1B NA 11,333
5/19/2004 1B 16 21,667
6/16/2004 1B 34 2,100
7/14/2004 1B 17 1,415
7/29/2004 1B NA 2,600
4/30/2002 2A 7.5 673
5/13/2002 2A 15 2,300
5/30/2002 2A 7.2 1,209
10/16/2002 2A 33 1,855
11/6/2002 2A 9.6 904
12/17/2002 2A 17 164
1/7/2003 2A 16 1,277
1/16/2003 2A 12 2,100
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A-11
Date Site Flow (cfs)1,2 Observed FC (#/100 mL)
1/21/2003 2A 14 22,600
1/30/2003 2A 12 156
2/12/2003 2A 13 100
2/25/2003 2A 38 275
3/19/2003 2A 24 6,000
4/28/2003 2A 20 840
6/12/2003 2A 21 1,733
7/2/2003 2A 75 4,900
7/24/2003 2A 18 1,450
8/6/2003 2A 28 2,100
8/20/2003 2A 14 1,817
9/3/2003 2A 19 3,500
9/15/2003 2A 14 4,000
10/1/2003 2A 13 505
10/15/2003 2A 14 2,200
11/5/2003 2A 15 6,500
11/19/2003 2A 590 7,600
12/10/2003 2A 39 9,200
12/17/2003 2A 30 625
2/18/2004 2A 24 870
3/9/2004 2A 17 1,295
3/24/2004 2A 17 4,200
4/7/2004 2A 16 5,900
4/20/2004 2A 22 5,500
5/3/2004 2A NA 5,600
5/19/2004 2A 16 1,120
6/16/2004 2A 34 1,607
4/30/2002 2B 7.5 560
5/13/2002 2B 15 1,291
5/30/2002 2B 7.2 1,200
10/16/2002 2B 33 9,500
11/6/2002 2B 9.6 1,044
12/17/2002 2B 17 4,750
1/7/2003 2B 16 1,215
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A-12
Date Site Flow (cfs)1,2 Observed FC (#/100 mL)
1/16/2003 2B 12 575
1/21/2003 2B 14 580
1/30/2003 2B 12 2,200
2/12/2003 2B 13 1,180
2/25/2003 2B 38 2,400
3/19/2003 2B 24 12,000
4/28/2003 2B 20 740
6/12/2003 2B 21 820
7/2/2003 2B 75 6,000
7/24/2003 2B 18 1,000
8/6/2003 2B 28 2,500
8/20/2003 2B 14 680
9/3/2003 2B 19 2,900
9/15/2003 2B 14 5,950
10/1/2003 2B 13 520
10/15/2003 2B 14 860
11/5/2003 2B 15 4,350
11/19/2003 2B 590 10,400
12/10/2003 2B 39 9,200
12/17/2003 2B 30 1,438
2/18/2004 2B 24 4,700
3/9/2004 2B 17 2,400
3/24/2004 2B 17 1,600
4/7/2004 2B 16 2,500
4/20/2004 2B 22 2,300
5/3/2004 2B NA 2,900
5/19/2004 2B 16 9,600
6/16/2004 2B 34 2,100
4/30/2002 3A 7.5 260
5/13/2002 3A 15 636
5/30/2002 3A 7.2 330
10/16/2002 3A 33 8,000
11/6/2002 3A 9.6 619
12/17/2002 3A 17 857
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A-13
Date Site Flow (cfs)1,2 Observed FC (#/100 mL)
1/7/2003 3A 16 540
1/16/2003 3A 12 333
1/21/2003 3A 14 4,350
1/30/2003 3A 12 1,225
2/12/2003 3A 13 740
2/25/2003 3A 38 680
3/19/2003 3A 24 11,500
4/28/2003 3A 20 178
6/12/2003 3A 21 630
7/2/2003 3A 75 4,400
7/24/2003 3A 18 480
8/6/2003 3A 28 960
8/20/2003 3A 14 515
9/3/2003 3A 19 470
9/15/2003 3A 14 3,100
10/1/2003 3A 13 365
10/15/2003 3A 14 400
11/5/2003 3A 15 11,600
11/19/2003 3A 590 12,000
12/10/2003 3A 39 4,950
12/17/2003 3A 30 32,500
2/18/2004 3A 24 2,400
3/9/2004 3A 17 4,450
3/24/2004 3A 17 14,533
4/7/2004 3A 16 1,180
4/20/2004 3A 22 760
5/3/2004 3A NA 700
5/19/2004 3A 16 720
6/16/2004 3A 34 1,160
7/14/2004 3A 17 1,492
7/29/2004 3A NA 1,877
4/30/2002 3B 7.5 100
5/13/2002 3B 15 360
5/30/2002 3B 7.2 222
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A-14
Date Site Flow (cfs)1,2 Observed FC (#/100 mL)
10/16/2002 3B 33 3,600
11/6/2002 3B 9.6 540
12/17/2002 3B 17 922
1/7/2003 3B 16 480
1/16/2003 3B 12 230
1/21/2003 3B 14 2,900
1/30/2003 3B 12 1,374
2/12/2003 3B 13 475
2/25/2003 3B 38 700
3/19/2003 3B 24 4,700
4/28/2003 3B 20 138
6/12/2003 3B 21 560
7/2/2003 3B 75 5,500
7/24/2003 3B 18 260
8/6/2003 3B 28 900
8/20/2003 3B 14 270
9/3/2003 3B 19 460
9/15/2003 3B 14 1,283
10/1/2003 3B 13 235
10/15/2003 3B 14 420
11/5/2003 3B 15 6,000
11/19/2003 3B 590 12,000
12/10/2003 3B 39 10,900
12/17/2003 3B 30 31,000
2/18/2004 3B 24 1,454
3/9/2004 3B 17 470
3/24/2004 3B 17 435
4/7/2004 3B 16 578
4/20/2004 3B 22 520
5/3/2004 3B NA 360
5/19/2004 3B 16 370
6/16/2004 3B 34 640
7/14/2004 3B 17 700
7/29/2004 3B NA 660
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A-15
Date Site Flow (cfs)1,2 Observed FC (#/100 mL)
1/7/2003 5A 16 940
1/21/2003 5A 14 1,862
6/12/2003 5A 21 1,417
7/2/2003 5A 75 2,200
7/24/2003 5A 18 6,000
8/6/2003 5A 28 154
8/20/2003 5A 14 137
9/3/2003 5A 19 290
9/15/2003 5A 14 1,040
10/1/2003 5A 13 163
10/15/2003 5A 14 470
11/5/2003 5A 15 6,700
11/19/2003 5A 590 12,000
12/10/2003 5A 39 9,938
12/17/2003 5A 30 69,000
2/18/2004 5A 24 4,600
3/9/2004 5A 17 254
3/24/2004 5A 17 1,575
4/7/2004 5A 16 520
4/20/2004 5A 22 220
5/3/2004 5A NA 320
5/19/2004 5A 16 2,900
6/16/2004 5A 34 580
7/14/2004 5A 17 500
1/7/2003 5B 16 4,000
1/21/2003 5B 14 15,733
6/12/2003 5B 21 1,100
7/2/2003 5B 75 2,133
7/24/2003 5B 18 6,000
8/6/2003 5B 28 500
8/20/2003 5B 14 760
9/3/2003 5B 19 4,900
9/15/2003 5B 14 2,800
10/1/2003 5B 13 455
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A-16
Date Site Flow (cfs)1,2 Observed FC (#/100 mL)
10/15/2003 5B 14 620
11/5/2003 5B 15 7,600
11/19/2003 5B 590 12,000
12/10/2003 5B 39 45,000
12/17/2003 5B 30 20,500
2/18/2004 5B 24 3,550
3/9/2004 5B 17 4,225
3/24/2004 5B 17 4,900
4/7/2004 5B 16 59,500
4/20/2004 5B 22 5,700
5/3/2004 5B NA 626
5/19/2004 5B 16 670
6/16/2004 5B 34 875
7/14/2004 5B 17 1,625
7/14/2004 6A 17 1,160
7/29/2004 6A NA 940
7/29/2004 6B NA 1,200
1Flow measured at water quality station.
2NA = flow measurement not available
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B-1
Appendix B Assimilative Capacity and Load
Reduction Calculations
Newfound Creek TMDL – Final Version Submitted to EPA January 2005

B-2
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B-3
B.1 DEVELOPMENT OF REGRESSION EQUATIONS
Regression equations were developed to predict fecal coliform load in Newfound Creek (CFU/d) at each
NCDENR monitoring station as a function of flow frequency. The regression relationship for each site is
a log-linear relationship (natural log of load as a function of flow frequency). All sampling data are
shown on the regression graphs, but the regression line is only based on observations with a flow duration
interval greater than 5 percent. High flow observations (duration less than 10 percent) are not used to
calculate load reductions, but may be useful in the estimation of the regression line. However,
observations at estimated durations less than about 5 percent (very high flows) appear to deviate from the
log-linear relationship and are excluded from the calculation of the regression line to prevent outliers
from biasing the predictions.
Results of the regression analyses for each station are summarized in Table B-1 through Table B-3.
Table B-1. Regression of Natural Logarithm of Fecal Coliform Load on Flow Frequency,
Newfound Creek at Jenkins Valley Road
Regression Statistics
Multiple R 0.8148
R Square 0.6639
Adjusted R Square 0.6509
Standard Error 1.0065
Observations 28

ANOVA
df SS MS F Significance F
Regression 1 52.0172 52.0172 51.3481 1.30768E-07
Residual 26 26.3388 1.0130
Total 27 78.3560

Coefficients Standard Error t Stat P-value Lower 95% Upper 95%
Intercept 28.0458 0.3300 84.9892 2.52E-33 27.3675 28.7241
Flow %le -4.6140 0.6439 -7.1658 1.31E-07 -5.9376 -3.2905

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B-4
Table B-2. Regression of Natural Logarithm of Fecal Coliform Load on Flow Frequency,
Newfound Creek at Highway 63
Regression Statistics
Multiple R 0.7211
R Square 0.5200
Adjusted R Square 0.4982
Standard Error 0.9782
Observations 24

ANOVA
df SS MS F Significance F
Regression 1 22.8036 22.8036 23.8309 7.02E-05
Residual 22 21.0516 0.9569
Total 23 43.8552

Coefficients Standard Error t Stat P-value Lower 95% Upper 95%
Intercept 27.0418 0.3478 77.7437 0.0000 26.3205 27.7632
Flow %le -3.4241 0.7014 -4.8817 0.0001 -4.8787 -1.9694

For McPeters Road, the regression has low explanatory power – indicating that load is only weakly
correlated to flow. The same approach may be used, however. In this case, the regression analysis
collapses toward an estimate of uncertainty at the predicted mean load.
Newfound Creek TMDL – Final Version Submitted to EPA January 2005

B-5
Table B-3. Regression of Natural Logarithm of Fecal Coliform Load on Flow Frequency,
Newfound Creek at McPeters Road
Regression Statistics
Multiple R 0.1952
R Square 0.0381
Adjusted R Square -0.0153
Standard Error 1.1885
Observations 20

ANOVA
df SS MS F Significance F
Regression 1 1.0074 1.0074 0.7131 0.4095
Residual 18 25.4267 1.4126
Total 19 26.4341

Coefficients Standard Error t Stat P-value Lower 95% Upper 95%
Intercept 22.0067 0.4567 48.1897 1.75E-20 21.0472 22.9661
Flow %le -0.6635 0.7857 -0.8445 0.4095 -2.3143 0.9872

B.2 ESTIMATION OF PREDICTION INTERVALS
The method requires the estimation of a prediction interval about the regression line. In addition, because
the regression is in log space, the bias inherent in conversion from log space to arithmetic space must be
addressed.
The regression equation yields a minimum variance unbiased estimate of the local mean value, µ0 of the
natural logarithms of load, conditional on a corresponding value of the independent variable, x0,
(expressed as the deviation from the mean of all observed x values), in this case representing the flow
fraction:
εββµ+⋅+=0100x ,
where is a random disturbance term. The desired confidence limit (in log space) is given by the
prediction interval estimate for an individual realization y0 with mean µ0. This interval addresses both the
uncertainty in estimating the mean and the variability of individual observations about the mean and is
given by:
11
2
2
0
2,00 ++⋅⋅±=∑−
i
yn x
x
nstyαµ,
Newfound Creek TMDL – Final Version Submitted to EPA January 2005

B-6
where sy is the sample standard deviation of the y values, and t
-2 is the Student’s t statistic with tail area


n-2 degrees of freedom. For a two-tailed 90 perc








Conversion from logarithmic to arithmetic space introduces a bias, as the transform is not symmetrical.
The exact minimum variance unbiased estimator of the arithmetic mean from the logarithmic mean does
not have a closed-form solution, but, for large samples, is closely approximated by (Gilbert, 1987):





+
=2
0
2
0
0
ysy
ew ,
where w0 is the estimator in arithmetic space and sy0
2 is the local variance about the mean line, or
∑+⋅=2
2
0
0
1
i
yy x
x
n
ss .

Newfound Creek TMDL – Final Version Submitted to EPA January 2005

C-1
Appendix C Public Notice
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Newfound Creek TMDL – Final Version Submitted to EPA January 2005

C-3

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C-4
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