ApprovedLongCreekTurbidityTMDL

Total Maximum Daily Loads (TMDLs) for Turbidity in
Long Creek, McAlpine Creek, Sugar Creek, Little Sugar
Creek, Irwin Creek, Henry Fork, and Mud Creek in North
Carolina

Final Report
January 2005
(Approved February 8th, 2005)

Catawba River and French Broad River Basins

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

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
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Turbidity TMDLs in the Catawba and French Broad Basins January 2005
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INDEX OF TMDL SUBMITTAL

303(d) List Information

State: North Carolina
Counties: Burke, Catawba, Henderson, Mecklenburg, Union
Basin: Catawba River and French Broad River Basins

303(d) Listed Waters in Catawba River Basin
Stream name Description Class Index # Subbasin 14 Digit HUC Miles
Long Creek From source to a point 0.6 mile
downstream of Mecklenburg County
SR 2074
C 11-120-(0.5)30834 03050101170020 5.1
Long Creek
Mecklenburg County SR 2074 to a
point 0.4 mile upstream of
Mecklenburg County SR 1606
WS-
IV
11-120-(2.5)30834 03050101170020 8.4
Long Creek From a point 0.4 mile upstream of
Mecklenburg County SR 1606 to
Lake Wylie, Catawba River
WS-
IV CA
11-120-(7) 30834 03050101170020 1.8
McAlpine Ck From source to SR 3356, (Sardis Rd)C 11-137-9a 30834 8.3
McAlpine Ck From SR 3356 to NC 51 C 11-137-9b 30834 03050103020050 6.3
McAlpine Ck From NC 51 to NC 521 C 11-137-9c 30834 03050103020050 4.7
McAlpine Ck From NC Hwy 521 to NC/SC
stateline
C 11-137-9d 30834 03050103020050 1.1
Sugar Creek From SR 1156 Mecklenburg, to
HWY 51
C 11-137b 30834 03050103020020 11.9
Sugar Creek From Hwy 51 to NC/SC border C 11-137c 30834 03050103020020 1.2
Little Sugar Ck From NC 51 to state line C 11-137-8c 30834 03050103020030 3.6
Irwin Creek From source to Sugar Creek C 11-137-1 30834 03050103020020 11.8
Henry Fork From SR 1143 to South Fork C 11-129-1-
(12.5)c
30835
03050102010030
8.0

303(d) Listed Waters in French Broad River Basin
Stream name Description Class Index # Subbasin 14 Digit HUC Miles
Mud Creek From source to Byers Cr C 6-55a 40302 06010105030040
06010105030030
06010105030020
15.2

Area of Impairment: 87.4 miles
Water Quality Standard Violated: Turbidity
Pollutant of Concern Turbidity
Water Quality Standards - Class C and WS-IV Waters: Turbidity not to exceed 50 NTU
Sources of Impairment: Land Development, Urban Runoff/Storm
Sewers, Municipal Point Sources, Agriculture

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
iv

Public Notice Information

A draft of the TMDL was publicly noticed through various means, including notification in local
newspapers, in The Charlotte Observer on November 17, 2004, and the Asheville Citizen-Times on
November 24, 2004. The TMDL was also available from the Division of Water Quality’s website
during the comment period at: http://h2o.enr.state.nc.us/tmdl/TMDL_list.htm. The public comment
period began November 17, 2004 and was held for 30 days.

Public Notice Date: November 17, 2004
Submittal Date: January 7, 2005
Establishment Date:
Did notification contain specific mention of TMDL proposal? Yes
Were comments received from the public? Yes
Was a responsiveness summary prepared? Yes

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
v
TMDL Information

Critical conditions: Turbidity exceedences occur under both wet and dry conditions
predominantly during late spring to early fall seasons.
Seasonality: Seasonal variation in hydrology, climatic conditions, and watershed
activities are represented through the use of a continuous flow gage and the
use of all readily available water quality data collected in the watershed.
Development tools: Load duration curves for Total Suspended Solids (TSS) 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.

TMDL Allocation Summary for Long Creek
Allocations (lbs/day at critical
flow conditions (15.3 cfs))
Source
Percent of
Total Land
Area
Estimated Percent of
the Non-background
TSS Load
Natural
Background
Additional
Allocation Total
Wasteload Allocation (WLA)
MS4 ar 59.45% 90.07% 324.6 675.4 1000.0
50 NTU
Load Allocation (LA)
Fore 36.40% 3.69% 198.6 27.7 226.2
Residenti 3.90% 5.92% 21.3 44.4 65.7
Agricultu 0.20% 0.26% 0.9 2.0 2.9
Other 0.10% 0.06% 0.7 0.4 1.1
Total LAs 40.60% 9.93% 222 74.4 296.0
Margin of Safety (MOS) 10%
Grand Total 100% 100% 546 750 1296

Streams Proposed for Delisting
Stream name Description Index # Subbasin Miles
McAlpine Creek From source to NC/SC border 11-137-9a, 11-137-
11-137-9c, 11-137-9d
30834 20.4
Sugar Creek From SR 1156 Mecklenburg to
NC/SC border
11-137b, 11-137c 30834 13.1
Little Sugar Ck From NC 51 to state line 11-137-8c 30834 3.6
Irwin Creek From source to Sugar Creek 11-137-1 30834 11.8
Henry Fork From SR 1143 to South Fork 11-129-1-(12.5)c 30835 8.0
Mud Creek From source to Byers Cr 6-55a 40302 15.2
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
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TABLE OF CONTENTS

INDEX OF FIGURES.............................................................................................................................VIII
INDEX OF TABLES..................................................................................................................................IX
1.0 INTRODUCTION .................................................................................................................................. 1
1.1 PROBLEM DEFINITION ..................................................................................................................... 1
1.2 TMDL COMPONENTS...................................................................................................................... 1
1.3 WATER QUALITY TARGET............................................................................................................... 3
1.4 WATERSHED DESCRIPTION.............................................................................................................. 4
1.4.1 Land use/ Land cover............................................................................................................ 11
1.4.2 Geology................................................................................................................................. 16
1.4.3 Soils ...................................................................................................................................... 16
1.5 WATER QUALITY MONITORING PROGRAM.................................................................................... 16
1.5.1 Biological Monitoring........................................................................................................... 16
1.5.2 Chemical Monitoring............................................................................................................17
1.5.3 Flow Gaging......................................................................................................................... 18
2.0 SOURCE ASSESSMENT .................................................................................................................... 19
2.1 ASSESSMENT OF POINT SOURCES .................................................................................................. 19
2.1.1 NPDES-Regulated Municipal and Industrial Wastewater Treatment Facilities .................. 19
2.1.2 NPDES General Permits ...................................................................................................... 19
2.2 ASSESSMENT OF NONPOINT AND STORMWATER SOURCES ............................................................ 21
2.2.1 Stormwater Discharges......................................................................................................... 22
2.2.2 Water Quality Assessment .................................................................................................... 22
3.0 TECHNICAL APPROACH ................................................................................................................ 24
3.1 TMDL ENDPOINTS........................................................................................................................ 24
3.2 LOAD DURATION CURVE FOR TOTAL SUSPENDED SOLIDS ............................................................ 24
3.3 ASSIMILATIVE CAPACITY .............................................................................................................. 26
4.0 TMDL CALCULATION ..................................................................................................................... 26
4.1 TMDL ENDPOINTS........................................................................................................................ 26
4.2 CRITICAL CONDITIONS AND SEASONAL VARIATION...................................................................... 26
4.3 MARGIN OF SAFETY ...................................................................................................................... 27
4.4 RESERVE CAPACITY ...................................................................................................................... 27
4.5 TMDL CALCULATION................................................................................................................... 27
4.6 BACKGROUND TURBIDITY............................................................................................................. 29
4.7 ALLOCATIONS ...............................................................................................................................29
4.7.1 Wasteload Allocations ..........................................................................................................29
4.7.2 Load Allocations................................................................................................................... 30
5.0 FOLLOW – UP MONITORING......................................................................................................... 31
6.0 IMPLEMENTATION.......................................................................................................................... 31
7.0 PUBLIC PARTICIPATION................................................................................................................ 34
8.0 ADDITIONAL INFORMATION........................................................................................................ 34
REFERENCES ........................................................................................................................................... 35
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
vii
APPENDIX A. BURKE, MECKLENBURG, CATAWBA AND HENDERSON COUNTIES - SOILS
GREATER THAN 1% OF COUNTY AREA (NRCS, 1991).................................................................. 37
APPENDIX B. BENTHIC MACROINVERTEBRATE RESULTS IN LONG CREEK, MCALPINE
CREEK, SUGAR CREEK, LITTLE SUGAR CREEK, IRWIN CREEK, HENRY FORK, AND
MUD CREEK WATERSHEDS ................................................................................................................ 39
APPENDIX C. NC DWQ AMBIENT MONITORING RESULTS FOR TSS AND TURBIDITY IN
LONG CREEK, MCALPINE CREEK, SUGAR CREEK, LITTLE SUGAR CREEK, IRWIN
CREEK, HENRY FORK, AND MUD CREEK WATERSHEDS.......................................................... 42
APPENDIX D LOAD DURATION CURVES FOR WATERS IN WHICH TMDLS WILL NOT BE
DEVELOPED. ............................................................................................................................................ 57
APPENDIX E DATA SOURCES USED TO DEVELOP THE LONG CREEK TMDL. .................... 60
APPENDIX F. NPDES PERMITTED FACILITIES WITHIN THE LONG CREEK WATERSHED.
...................................................................................................................................................................... 62
APPENDIX G. METHODOLOGY FOR DEVELOPING THE LOAD DURATION CURVE.......... 64
APPENDIX H. DEVELOPMENT OF REGRESSION EQUATION.................................................... 65
APPENDIX I. BACKGROUND TSS CONDITIONS IN LONG CREEK AS A FUNCTION OF
PERCENT OF FLOW EXCEEDENCE................................................................................................... 67
APPENDIX J. PUBLIC NOTIFICATION OF PUBLIC REVIEW DRAFT OF LONG CREEK
TURBIDITY TMDL................................................................................................................................... 68
APPENDIX K. RESPONSIVENESS SUMMARY TO TMDL REPORT COMMENTS.................... 71

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
viii

INDEX OF FIGURES
FIGURE 1. LONG CREEK WATERSHED. IMPAIRED STREAM LENGTH IS BASED ON THE 2004
INTEGRATED LIST OF IMPAIRED WATERS (2004 INTEGRATED 305(B) AND 303(D) REPORT).. 4
FIGURE 2. MCALPINE CREEK WATERSHED. IMPAIRED STREAM LENGTH IS BASED ON THE 2004
INTEGRATED LIST OF IMPAIRED WATERS (2004 INTEGRATED 305(B) AND 303(D) REPORT).. 5
FIGURE 3. SUGAR CREEK WATERSHED. IMPAIRED STREAM LENGTH IS BASED ON THE 2004
INTEGRATED LIST OF IMPAIRED WATERS (2004 INTEGRATED 305(B) AND 303(D) REPORT).. 6
FIGURE 4. LITTLE SUGAR CREEK WATERSHED. IMPAIRED STREAM LENGTH IS BASED ON THE 2004
INTEGRATED LIST OF IMPAIRED WATERS (2004 INTEGRATED 305(B) AND 303(D) REPORT).. 7
FIGURE 5. IRWIN CREEK WATERSHED. IMPAIRED STREAM LENGTH IS BASED ON THE 2004
INTEGRATED LIST OF IMPAIRED WATERS (2004 INTEGRATED 305(B) AND 303(D) REPORT).. 8
FIGURE 6. HENRY FORK WATERSHED. IMPAIRED STREAM LENGTH IS BASED ON THE 2004
INTEGRATED LIST OF IMPAIRED WATERS (2004 INTEGRATED 305(B) AND 303(D) REPORT).. 9
FIGURE 7. MUD CREEK WATERSHED. IMPAIRED STREAM LENGTH IS BASED ON THE 2004
INTEGRATED LIST OF IMPAIRED WATERS (2004 INTEGRATED 305(B) AND 303(D) REPORT).10
FIGURE 8. LAND USE/ LAND COVER DISTRIBUTION WITHIN THE LONG CREEK WATERSHED......... 11
FIGURE 9. LAND USE/ LAND COVER DISTRIBUTION WITHIN THE MCALPINE CREEK WATERSHED.12
FIGURE 10. LAND USE/ LAND COVER DISTRIBUTION WITHIN THE SUGAR CREEK WATERSHED..... 12
FIGURE 11. LAND USE/ LAND COVER DISTRIBUTION WITHIN THE LITTLE SUGAR CREEK
WATERSHED........................................................................................................................................ 13
FIGURE 12. LAND USE/ LAND COVER DISTRIBUTION WITHIN THE IRWIN CREEK WATERSHED...... 13
FIGURE 13. LAND USE/ LAND COVER DISTRIBUTION WITHIN THE HENRY FORK WATERSHED....... 14
FIGURE 14. LAND USE/ LAND COVER DISTRIBUTION WITHIN THE MUD CREEK WATERSHED........ 14
FIGURE 15. STREAMFLOW (USGS STATION 02142900) AND TURBIDITY MONITORING IN LONG
CREEK AT AMBIENT STATION C4040000 (LONG CREEK AT SR 2042 NEAR PAW CREEK)
DURING 1/1997-4/2004..................................................................................................................... 19
FIGURE 16. LINEAR REGRESSION FOR TSS-TURBIDITY AT LONG CREEK AT C4040000 AND USGS
STATION 02142900, LONG CREEK NEAR PAW CREEK, NC USING DATA COLLECTED DURING
YEARS 1997-2003.............................................................................................................................. 23
FIGURE 17. LOAD DURATION CURVE USING TSS AT LONG CREEK STATION C4040000 (1997-
2004) AND FLOW AT USGS 02142900, LONG CREEK NEAR PAW CREEK NC (1970-2004).
“TSS ESTIMATED” VALUES ARE BASED ON TURBIDITY VALUES AND APPLYING THE
TURBIDITY/TSS CORRELATION........................................................................................................ 25
FIGURE 18. LOAD DURATION CURVE USING TSS AT LONG CREEK STATION C4040000 (1997-
2004) AND FLOW AT USGS 02142900, LONG CREEK NEAR PAW CREEK NC (1970-2004)... 28

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
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INDEX OF TABLES
TABLE 1 DETAILED LAND USE/ LAND COVER DISTRIBUTION WITHIN LONG CREEK WATERSHED... 1
TABLE 2 DETAILED LAND USE/ LAND COVER DISTRIBUTION BY ACRES AND PERCENT OF AREA
WITHIN EACH OF THE IMPAIRED WATERSHEDS.............................................................................. 15
TABLE 3 SUMMARY OF 1997-2004 TURBIDITY DATA IN LONG CREEK, MCALPINE CREEK, SUGAR
CREEK, LITTLE SUGAR CREEK, IRWIN CREEK, HENRY FORK, AND MUD CREEK................... 17
TABLE 4 FLOW STATISTICS FOR LONG CREEK USGS GAGE STATION #02142900 DURING YEARS
1965-2004........................................................................................................................................... 18
TABLE 5 NUMBER OF VIOLATIONS TO THE 50 NTU TURBIDITY STANDARD IN LONG CREEK
CLASSIFIED BY FLOW RANGE............................................................................................................ 22
TABLE 6 NUMBER OF MEASUREMENTS OVER 17 MG TSS/L (EQUIVALENT TO 50 NTU TURBIDITY
STANDARD) IN LONG CREEK CLASSIFIED BY FLOW RANGE......................................................... 25
TABLE 7 VIOLATIONS TO THE 50 NTU STANDARD FOR EACH MONTH DURING THE 1997-2004
PERIOD................................................................................................................................................. 27
TABLE 8 TSS TARGET LOAD AND REDUCTION REQUIREMENTS CALCULATED USING THE LOAD-
DURATION CURVE ANALYSIS.......................................................................................................... 29
TABLE 9 TOTAL SUSPENDED SOLIDS WASTELOAD ALLOCATION AND LOAD ALLOCATIONS FOR
LONG CREEK...................................................................................................................................... 31

1.0 Introduction
1.1 Problem Definition
The 2002 North Carolina Water Quality Assessment and Impaired Waters List (also
known as the Integrated 305(b) and 303(d) Report) identified Long Creek, McAlpine
Creek, Sugar Creek, Little Sugar Creek, Irwin Creek, Henry Fork, and Mud Creek in the
Catawba River and French Broad River Basins as impaired by elevated turbidity. Based
on this report, the impaired segments (assessment units 11-120-(0.5), 11-120-(2.5), 11-
120-(7), 11-137-9a, 11-137-9b, 11-137-9c, 11-137-9d, 11-137b, 11-137c, 11-137-8c, 11-
137-1, 11-129-1-(12.5)c, 6-55a) include the portions of the above mentioned creeks as
described in Table 1. This report will establish a Total Maximum Daily Load (TMDL)
for turbidity for each of the stream segments listed in Table 1 and will serve as a
management approach aimed toward reducing loadings of sediment from various sources
in order to attain applicable surface water quality standards for turbidity.

Table 1 Detailed land use/ land cover distribution within Long Creek watershed.
Stream name Description Class Index # Subbasin Miles
Long Creek From source to a point 0.6 mile downstream of
Mecklenburg County SR 2074
C 11-120-(0.5)30834 5.1
Long Creek From a point 0.6 mile downstream of
Mecklenburg County SR 2074 to a point 0.4
mile upstream of Mecklenburg County SR 1606
WS-IV 11-120-(2.5)30834 8.4
Long Creek From a point 0.4 mile upstream of Mecklenburg
County SR 1606 to Lake Wylie, Catawba River
WS-IV
CA
11-120-(7) 30834 1.8
McAlpine Creek From source to SR 3356, (Sardis Rd) C 11-137-9a 30834 8.3
McAlpine Creek From SR 3356 to NC 51 C 11-137-9b 30834 6.3
McAlpine Creek From NC 51 to NC 521 C 11-137-9c 30834 4.7
McAlpine Creek From NC Hwy 521 to NC/SC stateline C 11-137-9d 30834 1.1
Sugar Creek From SR 1156 Mecklenburg, to HWY 51 C 11-137b 30834 11.9
Sugar Creek From Hwy 51 to NC/SC border C 11-137c 30834 1.2
Little Sugar
Creek
From NC 51 to state line C 11-137-8c 30834 3.6
Irwin Creek From source to Sugar Creek C 11-137-1 30834 11.8
Henry Fork From SR 1143 to South Fork C 11-129-1-
(12.5)c
30835 8
Mud Creek From source to Byers Cr C 6-55a 40302 15.2

1.2 TMDL Components
In accordance with Section 305(b) of the Federal Clean Water Act (CWA) (33 U.S.C.
1315(B)), the State of North Carolina is required to biennially prepare and submit to the
USEPA a report addressing the overall water quality of the State’s waters. This report is
commonly referred to as the 305(b) Report or the Water Quality Inventory Report. In
accordance with Section 303(d) of the Clean Water Act (CWA), the State is also required
to biennially prepare and submit to USEPA a report that identifies waters that do not
meet or are not expected to meet surface water quality standards (SWQS) after
implementation of technology-based effluent limitations or other required controls. This
report is commonly referred to as the 303(d) List. The 303(d) process requires that a
TMDL be developed for each of the waters appearing on Category 5 of North Carolina’s
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
2
Water Quality Assessment and Impaired Waters List. The objective of a TMDL is to
quantify the amount of a pollutant a water body can assimilate without violating a state’s
water quality standards and allocate that load capacity to point and nonpoint sources in
the form of wasteload allocations (WLAs), load allocations (LAs), and a margin of safety
(MOS) (USEPA, 1991). Generally, the primary components of a TMDL, as identified by
EPA (1991, 2000) and the Federal Advisory Committee (USEPA FACA, 1998) are as
follows:

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

Section 303(d) of the CWA and the Water Quality Planning and Management regulation
(USEPA, 2000) require EPA to review all TMDLs for approval or disapproval. Once
EPA approves a TMDL, then the waterbody may be moved to Category 4a of the
Integrated 305(b) and 303(d) Report. Waterbodies remain in Category 4a until
compliance with all water quality standards is achieved. Where conditions are not
appropriate for the development of a TMDL, management strategies may still result in
the restoration of water quality.

The goal of the TMDL program is to restore designated uses to water bodies. Thus, the
implementation of sediment controls throughout the watersheds will be necessary to
restore uses in the most downstream portion of each creek. Although a site-specific
implementation plan is not included as part of this TMDL, reduction strategies are
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
3
needed. The involvement of local governments and agencies will be critical in order to
develop implementation plans and reduction strategies. Implementation discussion will
begin during public review of the TMDL.

1.3 Water Quality Target
Turbidity is a unit of measurement quantifying the degree to which light traveling
through a water column is scattered by the suspended organic and inorganic particles.
The scattering of light increases with a greater suspended load. Turbidity is commonly
measured in Nephelometric Turbidity Units (NTU), but may also be measured in Jackson
Turbidity Units (JTU).

With the exception of portions of Long Creek, all of the impaired segments addressed in
this report have been classified by the NC DWQ as Class C. Class C waters are defined
as “Waters protected for secondary recreation, fishing, wildlife, fish and aquatic life
propagation and survival, agriculture and other uses suitable for Class C. Secondary
recreation includes wading, boating, and other uses involving human body contact with
water where such activities take place in an infrequent, unorganized, or incidental
manner.” Long Creek is classified as Class C from its source to a point 0.6 mile
downstream of Mecklenburg County SR 2074, as Class WS-IV from a point 0.6 mile
downstream of Mecklenburg County SR 2074 to a point 0.4 mile upstream of
Mecklenburg County SR 1606, and as WS-IV CA from a point 0.4 mile upstream of
Mecklenburg County SR 1606 to Lake Wylie, Catawba River. The water supply
watershed (WS) classification is assigned to watersheds based on land use characteristics
of the area. A Critical Area (CA) designation is also listed for watershed areas within a
half-mile and draining to the water supply intake or reservoir where an intake is located.
For turbidity, Class WS-IV, and WS-IV (CA) have the same water quality standard as
Class C. The North Carolina fresh water quality standard for turbidity in Class C waters
(T15A: NCAC 2B.0211 (3)k) states:

The turbidity in the receiving water shall not exceed 50 Nephelometric Turbidity
Units (NTU) in streams not designated as trout waters and 10 NTU in streams,
lakes or reservoirs designated as trout waters; for lakes and reservoirs not
designated as trout waters, the turbidity shall not exceed 25 NTU; if turbidity
exceeds these levels due to natural background conditions, the existing turbidity
level cannot be increased. Compliance with this turbidity standard can be met
when land management activities employ Best Management Practices (BMPs) [as
defined by Rule .0202 of this Section] recommended by the Designated Nonpoint
Source Agency [as defined by Rule .0202 of this Section]. BMPs must be in full
compliance with all specifications governing the proper design, installation,
operation and maintenance of such BMPs;

The in-stream numeric target is the restoration objective that is expected to be reached by
implementing the specified load reductions in this TMDL. The target allows for
evaluation of progress toward the goal of reaching water quality standards for the
impaired stream by comparing the in-stream data to the target. In all of the impaired
stream segments discussed in this report, the applicable water quality target is 50 NTUs.
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
4

1.4 Watershed Description

The Long Creek watershed includes portions of the city of Charlotte and drains north
central Mecklenburg County between Charlotte and Huntersville in the Southern Outer
Piedmont Ecoregion. The watershed is located within hydrologic unit 3050101170020
and includes Vances Twin Lakes, Dixon Branch, Swaringer Lake and McIntyre Creek.
Figure 1 identifies USGS gages, NCDWQ ambient stations, and major and minor NPDES
permitted facilities in the Long Creek watershed.
Figure 1. Long Creek watershed. Impaired stream length is based on the 2004 Integrated
List of Impaired Waters (2004 Integrated 305(b) and 303(d) Report).
5 0 5 Miles



















NC0086002
NC0031038

NC0004839

NC0046892

NC0046213

NC0005185

NC0021962

NC0046531

NC0022187

NC0032891
0214291555
02142900
C4040000
MECKLENBURG
Gum Branch
Gutter Branch McIntyre Creek
Dixon Branch
Thomas Pond
Long Creek
Hydrography - USGS 1:24,000
303(d) Impaired Reach (Turbidity)

Minor NPDES permitted facilities

Major NPDES permitted facilities
USGS Gage Station
DWQ Ambient Chemistry Station
N

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
5
The McAlpine Creek watershed is located entirely within the city of Charlotte in the
Southern Outer Piedmont Ecoregion. The watershed is located in four USGS 14-digit
HUCs: 3050103020050, 3050103020060, 3050103020040, 3050103020070 and drains
McMullen Creek, Campbell Creek, Irvins Creek, and Rocky Branch. Figure 2 identifies
USGS gages, NCDWQ ambient stations, and major and minor NPDES permitted
facilities in the McAlpine Creek watershed.

Figure 2. McAlpine Creek watershed. Impaired stream length is based on the 2004
Integrated List of Impaired Waters (2004 Integrated 305(b) and 303(d) Report).





















C9370000

NC0029181

NC0063789
02146700
02146750
02146670
02146600
02146562
MECKLENBURG
UNION
NC0024970
McMullen Creek
McMullen Creek
Rocky Branch
Fourmile Creek
Irvins Creek (McEwen Lake)
Campbell Creek
McAlpine Creek (Waverly Lake)
N
Hydrography - USGS 1:24,000
303(d) Impaired Reach (Turbidity)

Minor NPDES permitted facilities

Major NPDES permitted facilities
USGS Gage Station
DWQ Ambient Chemistry Station
Counties

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
6
The Sugar Creek watershed is located entirely within the city of Charlotte in the Southern
Outer Piedmont Ecoregion. The watershed is located within hydrologic unit
3050103020020 and drains McCullough Branch, Kings Branch, Coffey Creek, Irwin
Creek, Stewart Creek, Dillons Twins Lakes, and Lake Jo. Figure 3 identifies USGS
gages, NCDWQ ambient stations, and major and minor NPDES permitted facilities in the
Sugar Creek watershed.

Figure 3. Sugar Creek watershed. Impaired stream length is based on the 2004 Integrated
List of Impaired Waters (2004 Integrated 305(b) and 303(d) Report).


















Sugar Creek
C8896500
C9050000

NC0079758

NC0086517
02146381
02146348
02146300
02146315
02146285
02146211
NC0024945
MECKLENBURG COUNTY
Coffey Creek
Kings Branch
McCullough Branch
Irwin Creek
Stewart Creek
Dillons Twins Lakes and Lake Jo
Taggart Creek (Taggard Creek)
Hydrography - USGS 1:24,000
303(d) Impaired Reach (Turbidity)

Minor NPDES permitted facilities

Major NPDES permitted facilities
USGS Gage Station
DWQ Ambient Chemistry Station
N
4 0 4 8 Miles

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
7
The Little Sugar Creek watershed is located entirely within the city of Charlotte in the
Southern Outer Piedmont Ecoregion. The watershed is located within hydrologic unit
3050103020030 and drains Little Hope Creek, Dairy Branch, Edwards Branch, and Brier
Creek. Figure 4 identifies USGS gages, NCDWQ ambient stations, and major and minor
NPDES permitted facilities in the Little Sugar Creek watershed.

Figure 4. Little Sugar Creek watershed. Impaired stream length is based on the 2004
Integrated List of Impaired Waters (2004 Integrated 305(b) and 303(d) Report).
N
Hydrography - USGS 1:24,000
303(d) Impaired Reach (Turbidity)

Minor NPDES permitted facilities

Major NPDES permitted facilities
USGS Gage Station
DWQ Ambient Chemistry Station























C9210000

NC0084301

NC0086886
NC0085731
NC0087513

NC0085057
02146507
02146470
02146409
0214642825
02146530
0214620760
NC0024937
Brier Creek
Little Sugar Creek
Little Sugar Creek
Little Hope Creek
Dairy Branch
Edwards Branch
5 0 5 Miles

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
8
The Irwin Creek watershed is located entirely within the city of Charlotte in the Southern
Outer Piedmont Ecoregion. The watershed is located within hydrologic unit
3050103020020 and drains Stewart Creek, Dillons Twins Lakes, and Lake Jo. Figure 5
identifies USGS gages, NCDWQ ambient stations, and major and minor NPDES
permitted facilities in the Irwin Creek watershed.

Figure 5. Irwin Creek watershed. Impaired stream length is based on the 2004 Integrated
List of Impaired Waters (2004 Integrated 305(b) and 303(d) Report).








C8896500

NC0086517
02146300
02146285
0214627970
02146211
MECKLENBURG
COUNTY
NC0024945
Stewart Creek
Irwin Creek
Dillons Twins Lakes and Lake Jo
Hydrography - USGS 1:24,000
303(d) Impaired Reach (Turbidity)

Minor NPDES permitted facilities

Major NPDES permitted facilities
USGS Gage Station
DWQ Ambient Chemistry Station
2 0 2 Miles
N

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
9
Henry Fork drains central Burke County south of Morganton. It flows along the south
side of Hickory before joining with Jacob Fork to form the South Fork Catawba River in
Catawba County. The watershed is located within hydrologic units 3050102010010,
3050102010020, 3050102010030 and drains Jerry Branch, Hipp Creek, Ivy Creek, Stacy
Creek, Long Branch, Black Fox Branch, Daffy Creek, Ben Branch, Rock Creek, Abee
Creek (Queens Creek), Laurel Creek, Tims Creek, Longview Creek, Geitner Branch,
Barger Branch, and Muddy Creek. Figure 6 identifies USGS gages, NCDWQ ambient
stations, and major and minor NPDES permitted facilities in the Henry Fork watershed.

Figure 6. Henry Fork watershed. Impaired stream length is based on the 2004 Integrated
List of Impaired Waters (2004 Integrated 305(b) and 303(d) Report).









NC0086304
C4300000
C4360000

NC0040797
NC0050920
02143000
BURKE
CATAWBA
Henry Fork
Long Branch
Laurel Creek
Cub Creek
Rock Creek
Tims Creek
He Creek
Longview Creek
Geitner Branch
Abee Creek (Queens Creek)
Henry Fork
Morganton Valdese
Hickory
Urban Area
Counties
Hydrography - USGS 1:24,000
303(d) Impaired Reach (Turbidity)

Minor NPDES permitted facilities

Major NPDES permitted facilities
USGS Gage Station
DWQ Ambient Chemistry Station
N
3 0 3 6 Miles

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
10
The Mud Creek watershed is located entirely within Henderson County and drains
Hendersonville and portions of Laurel Park. Mud Creek is located in the Southern
Crystalline Ridges and Mountains and Broad Basins Ecoregions. The watershed is
located within hydrologic units 6010105030020, 6010105030030, 601010503004 0 and
drains Clear Creek, Lewis Creek, Henderson Creek, Laurel Branch, Wolfpen Creek,
Allen Branch, Devils Fork, Bat Fork, King Creek, Mud Creek, Perry Creek, Finley
Creek, Wash Creek, Britton Creek, Byers Creek, Featherstone Creek, Harper Creek,
Lanning Mill Creek, Kyles Creek, Puncheon Camp Creek, and Mill Creek. Figure 7
identifies USGS gages, NCDWQ ambient stations, and major and minor NPDES
permitted facilities in the Mud Creek watershed.

Figure 7. Mud Creek watershed. Impaired stream length is based on the 2004 Integrated
List of Impaired Waters (2004 Integrated 305(b) and 303(d) Report).
N








































NC0025534
E2120000

NC0079251
NC0066362

NC0074110

NC0071897
NC0083313

NC0036251

NC0024431

NC0074136

NC0073393

NC0075647

NC0037176

NC0068799

NC0069370

NC0071862

NC0033430

NC0086070
NC0076082
03446569
NC0036641
Laurel Park
Hendersonville
4 0 4 Miles Hydrography - USGS 1:24,000
303(d) Impaired Reach (Turbidity)

Minor NPDES permitted facilities

Major NPDES permitted facilities
USGS Gage Station
DWQ Ambient Chemistry Station

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
11
1.4.1 Land use/ Land cover
The land use/land cover characteristics of the watershed were determined using 1996 land
cover data that were developed from 1993-94 LANDSAT satellite imagery. The North
Carolina Center for Geographic Information and Analysis, in cooperation with the NC
Department of Transportation and the United States Environmental Protection Agency
Region IV Wetlands Division, contracted Earth Satellite Corporation of Rockville,
Maryland to generate comprehensive land cover data for the entire state of North
Carolina. Land cover/land use data for the Long Creek watershed are identified in Figures
8-14 and are summarized in Table 2. During the formation of this geographic dataset, the
proportion of synthetic cover was used to identify developed land as either low density
developed (50-80% synthetic cover) or high density developed (80-100% synthetic
cover) (Earth Satellite Corporation, 1997).

As shown in Figures 8-14 and Table 2, predominant landuses in each watershed vary
significantly. Sugar, Little Sugar, and Irwin Creeks are dominated by high density, urban
landuses with secondary landuses as mixed upland hardwoods, managed herbaceous
cover, and low density development. McAlpine Creek is dominated by southern yellow
pine, and low and high-density development. Long Creek, Henry Fork, and Mud Creek
are all predominately composed of mixed upland hardwoods and mixed herbaceous
cover.

Figure 8. Land use/ land cover distribution within the Long Creek watershed.
5 0 5 Mil
Landuse/ Landcover
Unconsolidated Sediment
Low Intensity Developed
High Intensity Developed
Southern Yellow Pine
Unmanaged Herbaceous Upland
Managed Herbaceous Cover
Mixed Shrubland
Deciduous Shrubland
Evergreen Shrubland
Bottomland Forest/Hardwood Swamps
Other Needleleaf Evergreen Forests
Mixed Hardwoods/Conifers
Other Broadleaf Deciduous Forests
Mountain Conifers
Mixed Upland Hardwoods
Cultivated
Water Bodies
Exposed Rock
Not Within Statewide Land Cover Database
N

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
12
Figure 9. Land use/ land cover distribution within the McAlpine Creek watershed.
5 0 5 Miles
Landuse/ Landcover
Unconsolidated Sediment
Low Intensity Developed
High Intensity Developed
Southern Yellow Pine
Unmanaged Herbaceous Upland
Managed Herbaceous Cover
Mixed Shrubland
Deciduous Shrubland
Evergreen Shrubland
Bottomland Forest/Hardwood Swamps
Other Needleleaf Evergreen Forests
Mixed Hardwoods/Conifers
Other Broadleaf Deciduous Forests
Mountain Conifers
Mixed Upland Hardwoods
Cultivated
Water Bodies
Exposed Rock
Not Within Statewide Land Cover Database
N

Figure 10. Land use/ land cover distribution within the Sugar Creek watershed.
4 0 4 8 Miles
Landuse/ Landcover
Unconsolidated Sediment
Low Intensity Developed
High Intensity Developed
Southern Yellow Pine
Unmanaged Herbaceous Upland
Managed Herbaceous Cover
Mixed Shrubland
Deciduous Shrubland
Evergreen Shrubland
Bottomland Forest/Hardwood Swamps
Other Needleleaf Evergreen Forests
Mixed Hardwoods/Conifers
Other Broadleaf Deciduous Forests
Mountain Conifers
Mixed Upland Hardwoods
Cultivated
Water Bodies
Exposed Rock
Not Within Statewide Land Cover Database
N

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
13
Figure 11. Land use/ land cover distribution within the Little Sugar Creek watershed.
N
Landuse/ Landcover
Unconsolidated Sediment
Low Intensity Developed
High Intensity Developed
Southern Yellow Pine
Unmanaged Herbaceous Upland
Managed Herbaceous Cover
Mixed Shrubland
Deciduous Shrubland
Evergreen Shrubland
Bottomland Forest/Hardwood Swamps
Other Needleleaf Evergreen Forests
Mixed Hardwoods/Conifers
Other Broadleaf Deciduous Forests
Mountain Conifers
Mixed Upland Hardwoods
Cultivated
Water Bodies
Exposed Rock
Not Within Statewide Land Cover Database
5 0 5 10 Miles

Figure 12. Land use/ land cover distribution within the Irwin Creek watershed.
Landuse/ Landcover
Unconsolidated Sediment
Low Intensity Developed
High Intensity Developed
Southern Yellow Pine
Unmanaged Herbaceous Upland
Managed Herbaceous Cover
Mixed Shrubland
Deciduous Shrubland
Evergreen Shrubland
Bottomland Forest/Hardwood Swamps
Other Needleleaf Evergreen Forests
Mixed Hardwoods/Conifers
Other Broadleaf Deciduous Forests
Mountain Conifers
Mixed Upland Hardwoods
Cultivated
Water Bodies
Exposed Rock
Not Within Statewide Land Cover Database
4 0 4 Miles
N

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
14
Figure 13. Land use/ land cover distribution within the Henry Fork watershed.
Landuse/La ndcover
Unconsolid ated Sedim ent
Low Intensity Deve loped
High Inten sity Develope d
Southern Yellow Pine
Unm anage d Herbace ous Uplan d
M anaged Herbaceou s Cover
M ixed Sh rubland
Deciduous Shrublan d
Evergreen Shrublan d
Bottom lan d Forest/H ardw ood Sw am ps
Other Ne edleleaf Eve rgreen Fo rests
M ixed Ha rdw o ods/Conifers
Other Broadleaf D eciduous F orests
M ountain Conifers
M ixed Up land Hard w oo ds
Cultivated
W ater B odies
Exposed R ock
Not W ithin Statew ide L and Cover Database
3 0 3 6 9 Mile s
N

Figure 14. Land use/ land cover distribution within the Mud Creek watershed.
N
Landuse/ Landcover
Unconsolidated Sediment
Low Intensity Developed
High Intensity Developed
Southern Yellow Pine
Unmanaged Herbaceous Upland
Managed Herbaceous Cover
Mixed Shrubland
Deciduous Shrubland
Evergreen Shrubland
Bottomland Forest/Hardwood Swamps
Other Needleleaf Evergreen Forests
Mixed Hardwoods/Conifers
Other Broadleaf Deciduous Forests
Mountain Conifers
Mixed Upland Hardwoods
Cultivated
Water Bodies
Exposed Rock
Not Within Statewide Land Cover Database
4 0 4 8 Miles
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
15
Table 2 Detailed land use/ land cover distribution by acres and percent of area within each of the impaired watersheds.
Land use/ Land cover
acres and % of area Long Creek
McAlpine
Creek Sugar Creek
Little
Sugar Creek Irwin Creek Henry Fork Mud Creek
Open Water 50 0.2% 122 0.2% 198 0.5% 0 0.0% 77 0.4% 33 0.0% 331 0.5%
Bottomland
Forest/Hardwood
Swamps
37 0.2% 1,750 2.9% 1,977 4.6% 764 2.4% 358 1.8% 50 0.1% 0 0.0%
Cultivated 73 0.3% 123 0.2% 80 0.2% 0 0.0% 3 0.0% 930 1.3% 1,897 2.6%
Deciduous Shrubland 56 0.2% 7 0.0% 28 0.1% 0 0.0% 6 0.0% 78 0.1% 0 0.0%
Evergreen Shrubland 23 0.1% 0 0.0% 16 0.0% 0 0.0% 16 0.1% 272 0.4% 479 0.7%
Exposed Rock 0 0.0% 0 0.0% 0 0.0% 0 0.0% 0 0.0% 240 0.3% 423 0.6%
Low Intensity
Developed
850 3.7% 9,032 15.0% 4,052 9.4% 6,304 19.4% 2785 14.2% 1,410 1.9% 1,235 1.7%
High Intensity
Developed
1,926 8.3% 10,430 17.4% 16,905 39.0% 10,420 32.1% 8067 41.0% 1,303 1.8% 1,593 2.2%
Managed Herbaceous
Cover
5,132 22.1% 8,866 14.8% 4,572 10.6% 2,004 6.2% 1889 9.6% 13,592 18.6% 19,963 27.7%
Mixed
Hardwoods/Conifers
2,031 8.7% 9,209 15.3% 4,232 9.8% 7,846 24.2% 2195 11.2% 22,537 30.8% 16,331 22.6%
Mixed Shrubland 0 0.0% 64 0.1% 75 0.2% 9 0.0% 0 0.0% 258 0.4% 194 0.3%
Mixed Upland
Hardwoods
12,525 53.9% 8,151 13.6% 7,192 16.6% 1,789 5.5% 3454 17.6% 27,050 37.0% 23,546 32.6%
Mountain Conifers 16 0.1% 133 0.2% 27 0.1% 4 0.0% 0 0.0% 4,915 6.7% 5,152 7.1%
Not Within Statewide
Land Cover Database
0 0.0% 0 0.0% 0 0.0% 0 0.0% 0 0.0% 1 0.0% 0 0.0%
Other Broadleaf
Deciduous Forests
1 0.0% 0 0.0% 0 0.0% 0 0.0% 0 0.0% 4 0.0% 0 0.0%
Other Needleleaf
Evergreen Forests
0 0.0% 0 0.0% 0 0.0% 0 0.0% 0 0.0% 5 0.0% 0 0.0%
Southern Yellow Pine 467 2.0% 12,090 20.1% 3,899 9.0% 3,308 10.2% 770 3.9% 60 0.1% 19 0.0%
Unconsolidated
Sediment
13 0.1% 0 0.0% 52 0.1% 0 0.0% 52 0.3% 33 0.0% 457 0.6%
Unmanaged
Herbaceous Upland
52 0.2% 82 0.1% 28 0.1% 0 0.0% 0 0.0% 355 0.5% 577 0.8%
Sum (acres) 23,253 60,059 43,333 32,451 19,673 73,126 72,195
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
16
1.4.2 Geology
Mecklenburg County includes Long Creek, McAlpine Creek, Sugar Creek and Little
Sugar Creek and lies within the Southern Outer Piedmont Ecoregion. Predominant rock
formations in this region include metamorphosed quartz diorite (PzZq), Granitic rock
(Dogb), Quartzite (CZq), and Metamorphosed mafic rock (PzZm). Henry Fork is located
in Catawba and Burke Counties in the Eastern Blackridge foothills and Northern Inner
Piedmont ecoregions. The Amphibolite and biotite gneiss (Czab), Megacrystic biotite
gneiss (Czba), Biotite gneiss and schist (CZbg) formations are the predominant
formations in Catawba and Burke Counties. Mud Creek, located in Henderson County, is
within the Southern Crystalline Ridges and Mountains and Broad Basins ecoregions.
Three predominant rock types occur in these regions: Henderson Gneiss (Chg), Granite
gneiss (Sogg), Garnet-mica schist (CZgms) (NCGS, 1991).

1.4.3 Soils
A full list of soils found in Mecklenburg, Burke, Catawba, and Henderson Counties is
located in Appendix A. The predominant soils in Mecklenburg County include Cecil
sandy loam, Cecil-Urban, Monacan, and Enon Sandy loam. The predominant soils in
Burke County include Evard-Cowee complex, Rhodhiss sandy loam, and Fairview sandy
clay loam. Predominat soils in Catawba County include Cecil clay loam, Pacolet soils,
Hiwassee loam, and Cecil sandy loam. Predominate soils in Henderson County include
Ashe stony sandy loam, Evard soils, Edneyville (Edneytown) fine sandy loam, and
Hayesville loam (USDA, 1991). With the exception of Cecil clay loam, Monacan, and
Pacolet soils, each of these soils has an erosion hazard of “severe” or “very severe”
indicating their potential for future erosion in inadequately protected areas. The estimated
erosion for each erosion classification is based on estimated annual soil loss in metric
tons per hectare. Values were determined using the Universal Soil Loss Equation
assuming bare soil conditions and using rainfall and climate factors for North Carolina. A
“severe” classification indicates a estimated loss of 10 to 25 tons per hectare and a “very
severe” indicates more than 25 tons per hectare of annual erosion (USDA online).

1.5 Water Quality Monitoring Program
As part of this TMDL, chemical and biological assessments were conducted throughout
the each watershed to characterize the impact and extent of turbidity impairment. Results
of this monitoring have shown occasional violations of the water quality standard for
turbidity in each of the waterbodies under discussion. Assessment of chemical and
biological data suggest continued water quality and habitat impairment for turbidity in
some of these waterbodies, while in others, water quality improvement in recent years.

1.5.1 Biological Monitoring
The NCDWQ maintains an extensive biological monitoring network of ambient stations.
A detailed 10-year history of fish and benthic invertebrate results at each station in the
impaired watersheds are presented in Appendix B. Recent benthic and fish monitoring in
McAlpine Creek, Sugar Creek, Little Sugar Creek, portions of Irwin Creek, and Mud
Creek resulted in fair and poor biological conditions. Recent monitoring in portions of
Irwin Creek and Henry Fork has shown good to fair biological conditions. No recent
monitoring is available for Long Creek.
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
17

1.5.2 Chemical Monitoring
Long Creek, McAlpine Creek, Sugar Creek, Little Sugar Creek, Irwin Creek, Henry Fork,
and Mud Creek were listed as impaired on North Carolina’s 1998 or 2000 303(d) Reports
based on turbidity data collected throughout the early and mid 1990’s (NCDENR 2004b).
Monthly ambient monitoring has continued at each station since the listing cycle in which
each of the waters were originally classified as impaired. As such, recent data (collected
between 1997-early 2004) will be analyzed to establish if turbidity remains a parameter
of impairment in each water. In the event that recent data supports the status of
impairement, a TMDL will be developed for that waterbody as appropriate. A summary
of turbidity monitoring for years 1997-2003 in each of these waterbodies is presented
below in Table 3. Raw datasets for turbidity and TSS in each of the below waterbodies
are presented in Appendix C.

Table 3 Summary of 1997-2004 turbidity data in Long Creek, McAlpine Creek, Sugar
Creek, Little Sugar Creek, Irwin Creek, Henry Fork, and Mud Creek.
Basin
Listed
Waterbody
NCDWQ
Ambient
station
Samples
(N)
Number
> 50 NTU
standard
Average
Turbidity
(NTU)
Median
Turbidity
(NTU)
Percent
exceed
standard
Catawba Long Creek C4040000 86 10 29.0 11.5 12%
Catawba McAlpine Ck C9370000 85 6 19.6 8.6 7%
Catawba Sugar Creek C9050000 86 7 32.1 7.6 8%
Catawba Little Sugar Ck C9210000 86 5 15.7 5.2 6%
Catawba Irwin Creek C8896500 84 6 17.3 5.1 7%
Catawba Henry Fork C4300000 84 4 11.1 6.4 5%
Catawba Henry Fork C4360000 82 4 18.3 8.2 5%
French Br Mud Creek E2120000 82 4 15.3 8.2 5%

An impaired waterbody is one that does not meet water quality uses, such as water
supply, fishing or propagation of aquatic life. Best professional judgment along with
numeric and narrative standards criteria and anti-degradation requirements defined in 40
CFR 131 is considered when evaluating the ability of a waterbody to serve its uses
(NCDWQ, 2004a). In the case of turbidity in the above stream segments, common
practice in applying professional judgment has been to apply impairment status to waters
in which the percent-exceedence value exceeds 10% (USEPA, 2003, and Catawba River
Basinwide Plan, 2004). The selection of 10% of standard exceedence as a ‘cut-off’ value
continues to be a common and appropriate method in categorizing waters as impaired.

As shown in Table 3, assessment of 1997-2004 turbidity data indicate less than 10%
exceedence at six of the seven ambient stations and thus attainment of water quality
standards at those locations. Based on the infrequent nature of the turbidity violations, the
development of a TMDL in McAlpine Creek, Sugar Creek, Little Sugar Creek, Irwin
Creek, Henry Fork, and Mud Creek is an inappropriate management response. Rather,
data is supportive of removing these waters from Category 5 of the Water Quality
Assessment and Impaired Waters List. A load duration curve analysis and brief
discussion of the six waterbodies proposed to be removed from Category 5 are provided
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
18
in Appendix D and below text. Long Creek does require a TMDL based on these standard
violations, thus Sections 1.5.3 through 8 will focus on the analysis of Long Creek.

In McAlpine Creek, six of eighty-six measurements violate the 50 NTU turbidity
standard. In all cases, violations occurred under high flow conditions in which the flow
was less than or equal to 10% exceedence. In Sugar Creek five of the seven violations
occurred under high flows exceeding 10% of flow duration, while two violations
occurred under flows that occur between 35 and 65% of the time. In Little Sugar Creek,
four of the 5 violations occurred under high flows that occur less than 10% of the time
while 1 violation occurred under flow conditions that occur approximately 12% of the
time. In Irwin Creek all six of the violations occur under flows that are equaled or
exceeded 11% of the time. In Henry Fork, four violations occur at each of the two
ambient stations. At ambient station C4360000, all four violations occur under flows that
occur between 10 and 95% of the time. At ambient station C4300000, violations were
widely spread from flow occurring 96% of the time to flows equal or exceeding 85% to
26% to 1% of the time. In Mud Creek, the two of the four violations occurred under
flows that were equaled or exceeded 10% of the time, the other two violations occurred at
flows equal or exceeding 46% and 67% of the time.

At the primary monitoring site along Long Creek, 86 daily observations were collected
from January 1997 to March 2004 ranging from 2 to 220 NTU. Daily observations at this
site are shown in Figure 15 along with the corresponding stream flow. The number of
violations to the 50 NTU water quality standard has increased in recent years and appears
to be associated with periods of elevated streamflow.

1.5.3 Flow Gaging
USGS has monitored stream flow at Station 02142900 (Long Creek near Paw Creek, NC)
since 1965. The station is located in Mecklenburg County at latitude 35°19'43", longitude
80°54'35". Data were obtained from the USGS NWIS system, including provisional data
updated through September 2004. Table 4 presents flow statistics for this station obtained
from the USGS and load duration curve analysis to be discussed in Section 2.2.2.

Table 4 Flow statistics for Long Creek USGS gage station #02142900 during years 1965-
2004.
Parameter Value
Count 14,325
Drainage Area 16.4 mi2
Average flow 18.1 cfs
Minimum flow 0.03 cfs
Maximum flow 1,600 cfs
High Flow Range (> 10% exceed) 31 cfs
Nonpoint Source Contributions from runoff (10-85%) 31- 2.2 cfs
Low Flow Range (95-100%) < 1.2 cfs

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
19
Figure 15. Streamflow (USGS station 02142900) and turbidity monitoring in Long Creek at
ambient station C4040000 (Long Creek at SR 2042 near Paw Creek) during 1/1997-4/2004.
0
100
200
300
400
500
1997 1998 1999 2000 2001 2002 2003 2004
Date
Tu
r
b
i
d
i
t
y

(
N
T
U
)

0
200
400
600
800
1000
1200
St
r
e
a
m
f
l
o
w

(
C
F
S
)
NC DWQ Ambient Data
50 NTU Standard
Streamflow (estimated)

2.0 Source Assessment
A source assessment is used to identify and characterize the known and suspected sources
of turbidity in the Long Creek watershed. This section outlines the assessment completed
for the purpose of developing this TMDL. The NCDENR’s Geographic Information
System (GIS) was used extensively to watershed characterization. Data sources used in
assessing Long Creek are identified in Appendix E.

2.1 Assessment of Point Sources
Two categories are included under this discussion; NPDES-regulated municipal and
industrial wastewater treatment facilities and NPDES general permitted facilities.

2.1.1 NPDES-Regulated Municipal and Industrial Wastewater Treatment
Facilities
There are no NPDES regulated municipal or industrial wastewater treatment facilities in
the Long Creek watershed and no continuous NPDES permitted facilities with turbidity
or TSS limits.

2.1.2 NPDES General Permits
Nine minor individual permitted facilities and six general permitted facilities are located
in the Long Creek watershed. A list of these facilities is presented in Appendix F.
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
20
General permitted facilities, while not subject to effluent TSS or turbidity limitations, are
required to develop a stormwater pollution prevention plan, and conduct qualitative
and/or quantitative measurements at each stormwater discharge outfall and vehicle
maintenance area. Sampling methodology and constituents to be measured are
characteristic of the volume and nature of the permitted discharge. For example, general
permits for mining operations require the permitee to measure settleable solids, total
suspended solids, turbidity, rainfall, event duration, and flow in stormwater discharge
areas. Measurements of pH, oil and grease, total suspended solids, rainfall, and flow are
required in on-site vehicle maintenance areas. Similarly, monitoring is required in mine
dewatering areas, wastewater associated with sand/gravel mining, and in overflow from
other process recycle wastewater systems.

Facilities submitting a notice of intent (NOI) for coverage under a general permit, prior to
establishment or approval of a TMDL for a priority pollutant(s) for stormwater
discharges (i.e. wet weather flows), may be covered under a general permit during its
term. For such facilities continued coverage under the reissuance of a general permit is
subject to the facility demonstrating that it does not have a reasonable potential to violate
applicable water quality standards for such pollutants due to the stormwater discharge(s).
In part, the decision to reissue is based on the submission of water quality measurements.
For facilities that do have a reasonable potential for violation of applicable water quality
standards due to the stormwater discharge(s) the facility shall apply for an individual
permit 180 days prior to the expiration of their general permit. Once the individual permit
is issued and becomes effective the facility will no longer have coverage under the
general permit.

All construction activities in the Long Creek watershed that disturb one or more acres of
land are subject to NC general permit NCG010000 and as such are required to not cause
or contribute to violations of Water Quality Standards. As stated in Permit NCG010000,
page 2, “The discharges allowed by this General Permit shall not cause or contribute to
violations of Water Quality Standards. Discharges allowed by this permit must meet
applicable wetland standards as outlined in 15A NCAC 2B .0230 and .0231 and water
quality certification requirements as outlined in 15A NCAC 2H .0500”. Monitoring
requirements for these construction activities are outlined in Section B (page 5) of
NCG010000. As stated, “All erosion and sedimentation control facilities shall be
inspected by or under the direction of the permittee at least once every seven calendar
days (at least twice every seven days for those facilities discharging to waters of the State
listed on the latest EPA approved 303(d) list for construction related indicators of
impairment such as turbidity or sedimentation) and within 24 hours after any storm event
of greater that 0.5 inches of rain per 24 hour period.” (NCG010000, Section B)

As per 40 CFR § 122.44(d)(1)(vii)(B), where a TMDL has been approved, NPDES
permits must contain effluent limits and conditions consistent with the requirements and
assumptions of the WLA in the TMDL. While effluent limitations are generally
expressed numerically, EPA guidance on NPDES-regulated municipal and small
construction storm water discharges is that these effluent limits be expressed as best
management practices (BMPs) or other similar requirements, rather than numeric effluent
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
21
limits (EPA, 2002). Compliance with the turbidity standard in Long Creek is expected to
be met when construction and other land management activities in the Long Creek
watershed employ adequate BMPs. Upon approval of this TMDL, DWQ will notify the
NC Division of Land Resources (DLR) and other relevant agencies, including county and
local offices in the Long Creek watershed (Mecklenburg County) responsible in
overseeing construction activities, as to the impaired status of Long Creek and the need
for a high degree of review in the construction permit review process.

2.2 Assessment of Nonpoint and Stormwater Sources
Nonpoint and stormwater sources include various erosional processes, including
sheetwash, gully and rill erosion, wind, landslides, dry ravel, and human excavation that
contribute sediment during storm or runoff events. Sediments are also often produced as a
result of stream channel and bank erosion and channel disturbance (EPA, 1999).

Nonpoint sources account for the vast majority of sediment loading to surface waters. A
few of these sources include:

Natural erosion occurring from the weathering of soils, rocks, and uncultivated
land; geological abrasion; and other natural phenomena.

Erosion from agricultural activities. This erosion can be due to the large land area
involved and the land-disturbing effects of cultivation. Grazing livestock can
leave areas of ground with little vegetative cover. Unconfined animals with direct
access to streams can cause streambank damage and erosion.

Erosion from unpaved roadways can be a significant source of sediment to rivers
and streams. Exposed soils, high runoff velocities and volumes and poor road
compaction all increase the potential for erosion.

Runoff from active or abandoned mines may be a significant source of solids
loading. Mining activities typically involve removal of vegetation, displacement
of soils and other significant land disturbing activities.

Soil erosion from forested land that occurs during timber harvesting and
reforestation activities. Timber harvesting includes the layout of access roads, log
decks, and skid trails; the construction and stabilization of these areas; and the
cutting of trees. Established forest areas produce very little erosion.

Streambank and streambed erosion processes often contribute a significant
portion of the overall sediment budget. The consequence of increased streambank
erosion is both water quality degradation as well as increased stream channel
instability and accelerated sediment yields. Streambank erosion can be traced to
two major factors: stream bank characteristics (erodibility potential) and
hydraulic/gravitational forces (Rosgen, online). The predominant processes of
stream bank erosion include: surface erosion, mass failure (planar and rotational),
fluvial entrainment (particle detachment by flowing water, generally at the bank
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
22
toe), freeze-thaw, dry ravel, ice scour, liquifaction/collapse, positive pore water
pressure, both saturated and unsaturated failures and soil piping.

2.2.1 Stormwater Discharges
Urban runoff can contribute significant amounts of turbidity to Long Creek. However,
much of this runoff is regulated in compliance with the NPDES Storm Water Phase I and
Phase II program (EPA, 2000). This rule applies to a unit of government such as a city or
county, which owns or operates a municipal separate storm sewer system (MS4). The
MS4 is required to obtain a National Point Source Discharge Elimination System
(NPDES) permit for their stormwater discharges to surface waters. As such, stormwater
runoff from areas within an MS4 is considered a point source. The cities of Charlotte and
Huntersville, Mecklenburg County, and NCDOT fall under the NPDES stormwater rules
and therefore maintain stormwater management programs. There are no continuous point
sources in the watershed with NPDES permit limits for turbidity or TSS.

According to the 2000 US Census Urbanized Area, the Long Creek watershed includes
portions of the Charlotte “urbanized area.” The total Phase II area included as part of the
Charlotte urbanized area within the Long Creek watershed is approximately 13,817 acres
(21.5 mi2), or approximately 59.5% of the total Long Creek watershed.

2.2.2 Water Quality Assessment
When streamflow gage information is available, a load duration curve (LDC) is useful in
identifying and differentiating between storm-driven and steady-input sources (Stiles
2002, Cleland 2002, ASIWPCA, 2002). This method determines the relative ranking of a
given flow based on the percent of time that historic flows exceed that value. Flow data
have been collected by USGS at the primary site (USGS Gage 02142900) from June 1,
1965 to the present. Excursions that occur only during low-flow events (flows that are
frequently exceeded) are likely caused by continuous or point source discharges, which
are generally diluted during storm events. Excursions that occur during high-flow events
(flows that are not frequently exceeded) are generally driven by storm-event runoff. A
mixture of point and nonpoint sources may cause excursions during normal flows. Table
5 identifies the number of turbidity samples exceeding the 50 NTU criterion under a
variety of flow conditions.

Table 5 Number of violations to the 50 NTU turbidity standard in Long Creek classified by
flow range.
Percent of Time Flows are Equaled or
Exceeded
Total number of
samples
Number of samples >
50 NTU
0% - 10% (high flows) 4 4
10% - 40% (moist conditions) 21 3
40% - 60% (mid-range flows) 16 1
60% - 95% (dry conditions) 35 1
95% - 100% (low flows) 10 1
All flows 83 10

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
23
Because turbidity is measured as NTUs and not as a concentration, another parameter that
is measured as a concentration must be used to represent turbidity loadings in the
watershed. For this TMDL, total nonfilterable solids (or TSS, method 00530) was
selected based on a 0.77 correlation value with turbidity. The correlation was determined
using the below formula:

( )( )
yx
yi
n
i
xi
xy
yxn
σσ
µµ
ρ ⋅
−−
=
∑
=1
1
where: 11≤≤−xyρ

Given this, a linear regression was developed between turbidity and TSS to allow for the
use of TSS values in developing a LDC. This regression is shown in Figure 16. Steps
used to develop the LDC are presented in Appendix G.

Figure 16. Linear regression for TSS-Turbidity at Long Creek at C4040000 and USGS
station 02142900, Long Creek near Paw Creek, NC using data collected during years 1997-
2003.
y = 0.2983x + 2.3061
0
10
20
30
40
50
60
70
80
0 25 50 75 100 125 150 175 200 225 250
Turbidity NTU
TS
S

m
g
/
L

Using the ambient data and USGS flow values, a load duration graph was developed for
the Long Creek ambient station (see Section 3.2). Monitoring data was then matched up
with the flow duration ranking based on the collection date. No flow estimation was
necessary given that the USGS flow gage (02142900) used to develop the LDC is located
adjacent to the ambient monitoring station. Figure 17 shows TSS data as a function of
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
24
flow duration at the Long Creek ambient station. As shown in Figure 17, the surface
water quality violations occur primarily under the 5%-40% range and thus are likely
attributable to storm driven sources.

3.0 Technical Approach
A LDC and mass-balance approach was chosen to calculate this TMDL for turbidity in
Long Creek. The load duration curve approach is advantageous because it is applicable in
the initial phases of source identification, in water quality assessment to quantifying the
magnitude of exceedence during critical conditions, and in implementation planning.
Given this, the LDC/mass balance approach was used to identify source types, specify the
assimilative capacity of the stream, and quantify the necessary load reduction needed to
meet water quality standards

3.1 TMDL Endpoints
As previously discussed, to meet North Carolina Surface Water Quality Standards,
instream turbidity values cannot exceed 50 NTU. Given that the turbidity standard is
expressed as NTU, a correlation between TSS and turbidity was necessary in applying the
LDC method. A discussion surrounding the selection of TSS as a surrogate for turbidity
is presented in Section 2.2.2. A correlation coefficient of 0.77 exists between the TSS –
turbidity data, and in using a linear regression, the following relationship is observed:

TSS = (0.2983* Turbidity) –2.3061
R2 = 0.60

Thus, the Surface Water Quality Standard turbidity target of 50 NTU in Class C waters
correlates to a TSS value of 17.2 mg/L.

3.2 Load Duration Curve for Total Suspended Solids
Values that plot below the LDC represent samples below the concentration threshold
whereas values that plot above represent samples that exceed the concentration threshold.
Loads that plot above the curve and in the region between 85 and 100 percent of days in
which flow is exceeded indicate a steady-input source contribution. Loads that plot in the
region between 10 and 70 percent suggest the presence of storm-driven source
contributions. A combination of both storm-driven and steady-input sources occurs in
the transition zone between 70 and 85 percent. Loads that plot above 95 percent or below
10 percent represent values occurring during either extreme low or high flows conditions
and are thus considered to be outside the region of technically and economically feasible
management.

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
25
Figure 17. Load duration curve using TSS at Long Creek station C4040000 (1997-2004) and
flow at USGS 02142900, Long Creek near Paw Creek NC (1970-2004). “TSS estimated”
values are based on turbidity values and applying the turbidity/TSS correlation.
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent of Days Flow is Equaled or Exceeded
TS
S

l
o
a
d

(
l
b
s
/
d
a
y
)

.
Reduced Limit Curve, TSS equivelant of 45 NTU
NCDWQ TSS Observed
NCDWQ TSS Estimated

The majority of excursions of the 50 NTU criterion occurred under moderate and higher
flows. A variety of techniques have been used in applying the LDC method. Cleland
(2003) has suggested separating the load duration results into different intervals
characteristic of flow regimes. Using this methodology, Table 6 identifies the number of
TSS measurements (both actual and estimated) that exceed 17 mg/L TSS, the TSS
equivalent to 50 NTU, under five flow regimes.

Table 6 Number of measurements over 17 mg TSS/L (equivalent to 50 NTU turbidity
standard) in Long Creek classified by flow range.
Percent of Time Flows are Equaled or
Exceeded
Total number of
samples
Number of TSS
samples > 17 mg/L TSS
0% - 10% (high flows) 4 1
10% - 40% (moist conditions) 21 6
40% - 60% (mid-range flows) 16 2
60% - 95% (dry conditions) 35 1
95% - 100% (low flows) 10 2
All flows 86 12

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
26
3.3 Assimilative Capacity
The assimilative capacity is the maximum level of pollutant allowable while achieving
the water quality goal. As discussed in section 2.2.2, TSS was selected as a surrogate for
turbidity in this TMDL. To determine the TSS assimilative capacity, the TSS
concentration equivalent to the turbidity standard of 50 NTU (17 mg TSS/L) was
multiplied by the full range of measured flow values. The assimilative capacity is shown
graphically in the form of a black line in Figure 17.

4.0 TMDL Calculation
A Total Maximum Daily Load (TMDL) represents the assimilative or carrying capacity
of a waterbody, taking into consideration point and nonpoint sources of pollutants of
concern, natural background and surface water withdrawals. A TMDL quantifies the
amount of a pollutant a water body can assimilate without violating a state’s water quality
standards (in our case, Class C and WS-IV freshwaters) and allocates that load capacity
to known point and nonpoint sources in the form of wasteload allocations (WLAs), load
allocations (LAs). 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. This definition is expressed by
the following equation:

TMDL =
WLAs +
LAs + MOS

A TMDL is developed as a mechanism for identifying all the contributors to surface
water quality impacts and setting goals for load reductions for pollutants of concern as
necessary to meet the SWQS. The Code of Federal Regulations (40 CFR §130.2(1))
states that TMDLs can be expressed in terms of mass per time, toxicity, or other
appropriate measures. This TMDL will be expressed in terms of mass per time and a
percent reduction that is calculated based on estimated stream flow and both estimated
and measured instream TSS concentrations. At total of 86 TSS values were used in this
TMDL analysis; 58 collected by the NC DWQ as part of routine monitoring between
1997 and 2004 and 28 values estimated based on instream turbidity measurements and
the turbidity-TSS correlation identified in section 2.2.

4.1 TMDL Endpoints
TMDL endpoints represent the instream water quality targets used in quantifying TMDLs
and their individual components. As discussed in Section 3, turbidity as a measure is not
applicable to the estimation of loading to a stream. TSS was selected as a surrogate
measure for turbidity. Based on the regression analysis, a TSS limit of 17 mg/L was
determined to be equivalent to a turbidity measure of 50 NTU. As will be discussed in
Section 4.4, a 10% explicit margin of safety was applied to the endpoint and resulted in a
reduction of the target value from 50 NTU to 45 NTU (17 mg TSS/L to 15.7 mg TSS/L).

4.2 Critical Conditions and Seasonal Variation
In Long Creek, elevated turbidity concentrations occur under both low, moderate, and
high flow conditions (Figure 17). The majority of turbidity violations during 1997-2004
occurred during the summer months between May and September with the most
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
27
violations occurring in July. Table 7 shows the number of violations in each month
during the 1997-2004 period. The TMDL has been set such that the turbidity standard is
met under all seasons and flow conditions for the 1997-2004 period.
Table 7 Violations to the 50 NTU standard for each month during the 1997-2004 period.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Violations (#) 2 0 0 0 1 1 3 1 1 0 1 0

4.3 Margin of Safety
A Margin of Safety (MOS) is provided to account for “lack of knowledge concerning the
relationship between effluent limitations and water quality” (40 CFR 130.7(c)). The MOS
may be incorporated into a TMDL either implicitly, through the use of conservative
assumptions to develop the allocations, or explicitly through a reduction in the TMDL
target. For this TMDL, an explicit margin of safety was incorporated in the analysis by
setting the TMDL target at 45 NTU, or equivalent 15.7 mg TSS/L, which is 10% lower
than the water quality target of 50 NTU or equivalent 17 mg TSS/L.

4.4 Reserve Capacity
Reserve capacity is an optional means of reserving a portion of the loading capacity to
allow for future growth. Reserve capacities are not included at this time. The loading
capacity of each stream is expressed as a function of the current load (Section 4.0), and
both WLAs and LAs are expressed as reductions for the entire Long Creek watershed.
Therefore, the reductions from current levels, outlined in this TMDL, must be attained in
consideration of any new sources that may accompany future development. Strategies
for source reduction will apply equally to new development as to existing development.

4.5 TMDL Calculation
The LDC presented in Figure 17 for 1997-2004 data is used as the basis for estimating
the TMDL. The LDC presents a maximum allowable concentration of 15.2 mg TSS/L
(value includes a 10% MOS and is equivalent to 45 NTU) and identifies a maximum
allowable load under any given flow experienced in Long Creek. The TMDL calculation
focuses on measurements observed under a range of normal or expected flow conditions
and excludes data collected under extremely high flows (occurring less than 10% of the
time) and low flows (occurring more than 95% of the time). While data obtained under
extreme flow conditions are not used to develop the TMDL, they may be appropriate for
decision making during TMDL implementation.

For this report, the TMDL calculation is accomplished in a manner similar to previous
TMDLs in which reductions are based on a confidence interval on a regression line
(NCDWQ, 2004c). The analysis is accomplished by using the LDC to establish a
regression model to predict load as a function of flow percentage. A confidence interval
on the regression line is then developed with the interval reflecting the allowable level of
exceedence to the water quality criterion. The confidence interval is a prediction interval
about the regression line. For turbidity, a waterbody is considered ‘not-impaired’ by
NCDWQ if ten-percent or less of the measurements do not exceed 50 NTU. Thus, for
turbidity, the upper 80th percentile confidence interval is sufficient to meet the ten percent
or less assessment criteria since ten percent of the observations are expected to fall in
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
28
both the upper and lower tails of the distribution. Additional detail on the methodology
can be found in Appendix H.

The regression equation and upper 80th percentile is shown in Figure 18. The exponential
regression line and confidence interval were fit to the values between 10% and 95%
percent flow exceedence. Allowable loading was then calculated at each percentage
between 10% and 95% based on the MOS-adjusted target concentration and the 80th
percentile confidence interval to the regression line. A load reduction was determined by
calculating the difference between the assimilative capacity (i.e. Reduced Limit Curve)
and corresponding 80th percentile confidence interval based on corresponding flow. The
existing and target loadings were estimated within each of the five flow range intervals
and are summarized in Table 8. The Long Creek TMDL analysis proposes a 58.4%-
reduction, specifically targeted toward conditions in which the flow recurrence interval is
40% or less (approximately 8.9 cfs or higher).

Figure 18. Load duration curve using TSS at Long Creek station C4040000 (1997-2004) and
flow at USGS 02142900, Long Creek near Paw Creek NC (1970-2004).

y = 7033.3e-4.2837x
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
0% 10% 20% 30% 40% 50% 60% 70% 80% 90%
Percent of Days Flow is Equaled or Exceeded
TS
S

l
o
a
d

(
l
b
s
/
d
a
y
)

.
80th Upper Percentile of Log-Linear Regression
Log-Linear Regression
Reduced Limit Curve, TSS equivelant of 45 NTU
NCDWQ TSS Observed
NCDWQ TSS Estimated
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
29
Table 8 TSS Target Load and Reduction Requirements Calculated using the Load-Duration
Curve Analysis.
Flow Range
Critical
Percentile
Flow
(cfs)
Target
Load
(lbs/day)
80th
Prediction
Limit
(lbs/day)
Reduction
Required
(Percent)
0% - 10% (high flows) 10.0% 31 2,286 4,583 50.1%
10% - 40% (moist conditions) 19.4% 17 1,296 3,117 58.4%
40% - 60% (mid-range flows) 41.2% 8.8 663 1,215 45.4%
60% - 90% (dry conditions) 61.1% 4.9 373 516 27.6%
90% - 95% (low flows) 94.9% 1.2 91 120 23.9%
The critical percentile is the value within the flow range in which the ratio of the 80th percentile limit to the
target load is greatest.
Flow (cfs) is the corresponding value to each critical percentile.
Target Load is the value of the adjusted (lowered by 10) instantaneous criterion limit curve at the specified
critical percentile and flow.
Reduction required is the calculated as (80th percentile prediction limit – target load)/(80th percentile
prediction limit)

4.6 Background Turbidity
As discussed in Section 1.4.3, the Long Creek watershed contains a variety of soils
classified as having a high or severe hazard of water erosion. The natural transport of
sediment, as erosion and resuspension, is an important driver in maintaining aquatic
health and quality. For the purposes of this TMDL, natural background levels of turbidity
were estimated for flows within the 10%-95% recurrence interval range. Using the LDC
method, an exponential regression line was fit to the data (1997-2004) within the 10%-
90% flow interval and below the TSS equivalent of the turbidity surface water quality
threshold of 50 NTU. As shown in Appendix I, background conditions are estimated
from the regression line to be approximately 5.0 mg TSS/L or 9.0 NTUs under lower
flows (occur approximately 95% of the time) and approximately 5.3 mg TSS/L or 10.1
NTUs under higher flows (occur approximately 10% of the time). Using estimates
obtained under each percent flow between 10 and 90, on average, the background TSS
concentration in Long Creek is 4.7 mg/L and the background turbidity is 8.3 NTU.

4.7 Allocations
As identified in Table 8, a 58.4% reduction in TSS loading is necessary to meet the
turbidity standard of 50 NTU under all flow conditions. Additional analysis is required to
address the TMDL reduction by identifying point and nonpoint contributors of turbidity
and calculating wasteload and load allocations. The wasteload allocation and load
allocations are estimated by similar methods and combined into one table below (Table
9). Activities not receiving an allocation in this TMDL are assumed to have an implicit
zero allocation for turbidity and TSS.

4.7.1 Wasteload Allocations
There are currently no permitted point sources in the watershed. However, the entire
county of Mecklenburg is authorized to discharge stormwater from its Municipal
Separate Storm Sewer System (MS4) under EPA’s NPDES Phase I stormwater permit
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
30
program. The MS4 designation, pursuant to 40 CFR § 122.26(b)(8), refers to a
conveyance or system of conveyances that are owned by a public entity and designed or
used for collecting or conveying stormwater. Within the Long Creek watershed, the MS4
designation is assumed to apply to the land area in the watershed that is within the
corporate limits of Charlotte and Huntersville, or which falls within the “high intensity
developed” land use category and is outside these cities but within Mecklenburg County.
For the purposes of this report, the total MS4 area in the Long Creek watershed is
approximated at 13,817 acres or 59.5% of the watershed area.

A wasteload allocation is assigned to these land areas consistent with the NPDES Phase I
Stormwater program. The assignment of the wasteload allocation is made on an areal
basis by the same methods used to develop load allocations in Section 4.7.2. The total
MS4 wasteload allocation is 1,000 lbs/day at 15.3 cfs critical flow (refer to Table 9).
Future urban/suburban development within the watershed will also fall under the MS4
NPDES permit, and any associated WLA with the new development will be determined
by shifting a portion of the LA to the WLA.

The WLA associated with construction and other land management activities, as
discussed in Section 2.1.2, is equivalent to the surface water quality standard for turbidity
in that any construction activity cannot cause or contribute to a violation of the water
quality standard. As discussed, these WLAs will continue to be expressed as BMPs in
general or individual construction permits rather than as numeric effluent limits.

4.7.2 Load Allocations
Load allocations account for the portion of the TMDL assigned to nonpoint sources.
According to 40 CFR § 130.2(g), load allocations are “best estimates of the loading,
which may range from reasonably accurate estimates to gross allotments, depending on
the availability of data and appropriate techniques for predicting the loading. Wherever
possible, natural and nonpoint source loads should be distinguished.” The total of the
wasteload allocation and load allocations for Long Creek is equivalent to the target load
of 1290 lbs/day at the critical flow condition of 15.3 cfs.

For this TMDL, generalized landuse load allocations have been estimated based on the
proportionate area in the watershed. Natural background loading rates are applied
equally to all land areas and are also assigned based on the percentage of land in the
watershed in each land use. The natural background loading, as explained in Section 4.6,
is estimated from the LDC and an exponential regression line through values that meet
the 50 NTU criteria. The remainder of the load allocation is assigned to those land uses
that are likely to contribute TSS load at rates above natural background; primarily
agriculture and residential land and the portion of forest area estimated to have been cut
within the past year. The acreage of forest area contributing above background conditions
was estimated at 566 acres. The MS4 WLA and LAs are summarized below in Table 9.

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
31

Table 9 Total Suspended Solids Wasteload Allocation and Load Allocations for Long Creek.
Allocations (lbs/day at 15.3 cfs flow)
Source
Percent of
Total Land Area
the Non-background
TSS Load
Natural
Background
Additional
Allocation Total
Wasteload Allocation (WLA)
MS4 ar 59.45% 90.07% 324.6 675.4 1000.0
50 NTU
Load Allocation (LA)
Fore 36.40% 3.69% 198.6 27.7 226.2
Residenti 3.90% 5.92% 21.3 44.4 65.7
Agricultu 0.20% 0.26% 0.9 2.0 2.9
Other 0.10% 0.06% 0.7 0.4 1.1
Total LAs 40.60% 9.93% 222 74.4 296.0
Margin of Safety (MOS) 10%
Grand Total 100% 100% 546 750 1296
Notes: The WLA associated with construction and other land management activities, as discussed in Section 2.1.2, is
equivalent to the surface water quality standard for turbidity in that any construction activity cannot cause or contribute
to a violation of the water quality standard. As discussed, these WLAs are and will be expressed as BMPs in the
general or individual construction permits rather than as numeric effluent limits.
“Other” includes water and unconsolidated sediment outside the MS4 area.

5.0 Follow – up Monitoring
Turbidity monitoring will continue on a monthly interval at the Long Creek ambient
monitoring station C4040000 at SR 2042 near Paw Creek and will allow for the
evaluation of progress towards the goal of reaching the turbidity water quality standard.
Additional monitoring could focus on identifying critical areas of streambank erosion and
turbidity source assessment in the watershed. This would further aid in the evaluation of
the progress towards meeting the water quality standard.

6.0 Implementation
Recent intensive construction and other land disturbing activities are the primary source
of suspended sediment in Long Creek and its tributaries. Erosion problems associated
with land-disturbing activities are compounded by increased flows, which result from an
increase in impervious area after development. Enforcement of stormwater BMP
requirements for construction sites and urban stormwater controls for sediment are
potential management options for improving turbidity levels. Among these measures are
construction entrances, diversion ditches and berms, sediment basins, and silt fences,
which, to be effective, must be installed and maintained from the initiation of land
disturbing activities until the establishment of permanent soil stabilization measures.
While stormwater controls are required on construction sites, significant loadings can
occur due to initial periods of land disturbance before controls are in place or during high
rainfall periods during which the controls are inadequate. North Carolina Phase II rules
require development, implementation, and enforcement of an erosion and sediment
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
32
control program for construction activities that disturb one or more acres of land. In
addition, Phase II rules require the development, implementation, and enforcement of a
program to address discharges of post-construction storm water runoff from new
development and redevelopment areas.

Implementation of conservation management plans and best management practices are
the best means of controlling agricultural sources of suspended solids. Several programs
are available to assist farmers in the development and implementation of conservation
management plans and best management practices. The Natural Resource Conservation
Service is the primary source of assistance for landowners in the development of resource
management pertaining to soil conservation, water quality improvement, wildlife habitat
enhancement, and irrigation water management. The USDA Farm Services Agency
performs most of the funding assistance. All agricultural technical assistance is
coordinated through the locally led Naturally Resource Conservation Service offices (Soil
Conservation Districts). The funding programs include: The Environmental Quality
Incentive Program (EQIP), The Conservation Reserve Program (CRP), and Soil & Water
Conservation Cost-Sharing Program practices

Management Strategies
Management measures are “economically achievable measures for the control of the
addition of pollutants from existing and new categories and classes of nonpoint and
stormwater sources of pollution, which reflect the greatest degree of pollutant reduction
achievable through the application of the best available nonpoint and stormwater source
pollution control practices, technologies, processes, siting criteria, operating methods, or
other alternatives” (USEPA, 1993). The City of Charlotte has a variety of mechanisms
already in place to protect and enhance water quality in Long Creek. Two means by
which the City of Charlotte is already addressing sediment in the Long Creek watershed
are discussed below.

The City of Charlotte is the agency responsible and active in preventing the discharge of
sediment to the surface waters and maintaining and restoring water quality conditions in
the streams and lakes in the cities jurisdiction. This jurisdiction encompasses 70% of
Mecklenburg County and includes the City’s Extra-Territorial Jurisdiction (ETJ). One of
the goals of the City of Charlotte is to achieve a 25% reduction in total suspended solid
(TSS) loads in streams that have established in-stream storm water monitoring sites. For
those streams in the County where in-stream monitoring sites have not been established,
the goal is to prevent turbidity levels from increasing in excess of 25% downstream of
construction sites as measured by portable, automated monitoring units. The
Mecklenburg County Soil Erosion and Sedimentation Control Ordinance (MCSESCO)
outlines the measures in which Mecklenburg County will regulate the installation and
maintenance of stormwater control devices (City of Charlotte Mecklenburg, 2004).

A second mechanism by which the City of Charlotte is addressing sediment in Long
Creek is the Surface Water Improvement and Management (S.W.I.M.) Program. The
S.W.I.M. approach has prioritized Mecklenburg’s creek basins and focus on preventing
further degradation, preserving the best waters, improve the good waters, and remediating
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
33
the worst waters. The program has been successful in improving water quality conditions,
enhancing efforts to enforce erosion control ordinances, reducing sediment levels in some
streams by as much as 79 percent, establishing vegetative stream buffers county wide
through the adoption of ordinances, and in the development of automated water quality
monitoring techniques. The automated monitoring technique was employed in
cooperation with NCDOT to ensure the protection of Long Creek from sediment
discharges from I-485 construction activities and is being expanded to other locations
around the county (City of Charlotte Mecklenburg, 2004).

S.W.I.M. Phase II was implemented in 2002 and started a four-year process aimed at
maintaining and/or restoring water quality conditions in identified special interest
watersheds to fulfill Mecklenburg County’s goal of "swimmable/fishable" waters. During
its first year of implementation, S.W.I.M. Phase II made significant progress toward
achieving this goal. In general, S.W.I.M. Phase II utilizes the tools developed in S.W.I.M.
Phase I, such as water quality monitoring and modeling. Phase III is planned for
implementation in 2006 for the purpose of applying the techniques developed in Phases I
and II to the remaining waters county wide with the ultimate goal of achieving the
Board’s "swimmable/fishable" goal by 2015. The S.W.I.M. Program is being used to
fulfill the Phase II Storm Water Permit requirements for Mecklenburg County and the six
towns in the county including Cornelius, Davidson, Huntersville, Matthews, Mint Hill
and Pineville. Under the S.W.I.M. Program, a Storm Water Management Program Plan
was developed and a joint permit application submitted to the state in February 2003.
Implementation of the plan began on July 1, 2003 (City of Charlotte Mecklenburg, 2004).

The NC Department of Transportation is also actively involved in managing and reducing
sediment erosion through the Sediment and Erosion control program as part of their
NPDES Highway Stormwater Program. The below paragraphs were obtained from
NCDOT to elaborate on their work in the Catawba Basin (full letter found in Appendix
K).

Presently, the NCDOT program is evaluating the water quality impact of road
construction in the Catawba River Basin through three related projects. The first project
involves detailed water quality monitoring of the Long Creek Watershed, the second is
evaluating various methods to reduce erosion and off-site sediment movement, and the
third addresses sediment loading from secondary road construction activities. The first
two projects are being conducted in Mecklenburg County and the third project noted is
located in Burke County.

In conjunction with Mecklenburg County’s S.W.I.M Program, the first project is
collecting detailed water quality data at 15 locations along a portion of Long Creek.
These data are being collected in 15 minutes intervals to determine in “real time” if
selected water quality parameters, with an emphasis on turbidity, are being violated. If a
problem is detected, the monitoring system includes the capability to send alerts to
Mecklenburg County’s Water Quality Program and the NCDOT, such that staff can
quickly respond to determine and correct the source of the water quality violation. The
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
34
project has been in place for almost two years with onsite management provided by
Mecklenburg County.

The second project is comparing the effectiveness of various innovative erosion control
systems which include the use of polyacrylamides, rolled erosion control products, and
bonded fiber matrix hydromulching. Testing of these BMPs is taking place on a segment
of the Charlotte I-485 Outer Loop. These systems are being installed, evaluated, and
modified if needed to improve their effectiveness. The project has been active for over a
year and is directed by Drs. Richard McLaughlin and Greg Jennings of North Carolina
State University.

The third project is on a secondary road bridge construction project in Burke County.
Single stage samplers have been installed up and downstream to monitor pre, during, and
post construction TSS and turbidity (NTU) levels. A crest gage has been installed to
monitor stream stage levels to develop a stage/discharge relationship. Sediment loading
values have been developed thus far for the pre-construction phase. Dr. Garry Grabow
with North Carolina State University has provided general project oversight. The
NCDOT has approximately 30 other sites across the state also under similar
investigation.

7.0 Public Participation
The TMDL was publicly noticed in The Charlotte Observer on November 17, 2004, the
Asheville Citizen-Times on November 24, 2004, and comments on the TMDL were
accepted over a period of thirty days.

8.0 Additional 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/index.htm

Technical questions regarding this TMDL should be directed to the following members
of the DWQ Modeling/TMDL Unit:

Brian Jacobson, Modeler
e-mail: [e-mail]

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
35

References
ASIWPCA TMDL, “Brown Bag,” Conference Call on Load Duration Curve Methodology, June
12, 2002.

City of Charlotte, Mecklenburg, North Carolina. 2004. Online at:
http://www.charmeck.org/Departments/LUESA/Water+and+Land+Resources/Programs/
Water+Quality/Home.htm

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.

Earth Satellite Corporation (EarthSat), 19980612, Statewide Land Cover - 1996: EarthSat,
Raleigh, North Carolina

Gilbert, R.O. 1987. Statistical Methods for Environmental Pollution Monitoring. Van Nostrand
Reinhold, New York.

Kansas Department of Health and Environment, 2002. Data Analysis: Methodology Used in
Kansas Lake TMDLs: Explanation of Bacteria TMDL Curves (PDF): Kansas TMDL
Curve Methodology. Online: http://www.kdhe.state.ks.us/tmdl/Data.htm.

North Carolina Department of Environment and Natural Resources, Division of Water Quality,
2003, TMDL Study of Lower Creek/Spainhour Creek. Catawba River Basin, Subbasin
31, Caldwell County.

North Carolina Department of Environment and Natural Resources, Division of Water Quality,
2002, Water Quality Assessment and Impaired Waters List (2002 Integrated 305(b) and
303(d) Report (Final), North Carolina Department of Environment and Natural
Resources, Division of Water Quality, Raleigh, North Carolina.

North Carolina Department of Environment and Natural Resources, Division of Water Quality,
2004a . Catawba River Basinwide Water Quality Management Plan. Raleigh, NC.

North Carolina Department of Environment and Natural Resources, Division of Water Quality,
2004b, Water Quality Assessment and Impaired Waters List (2004 Integrated 305(b) and
303(d) Report (Draft), North Carolina Department of Environment and Natural
Resources, Division of Water Quality, Raleigh, North Carolina.

North Carolina Department of Environment and Natural Resources, Division of Water Quality,
2004c, TMDL Study of Chicod Creek. Tar-Pamlico River Basin.

North Carolina Geological Survey. 1991. Generalized Geologic Map of North Carolina. Raleigh,
NC 27687.

Rosgen. D.L., A Practical Method of Computing Streambank Erosion Rate. Wildland Hydrology,
Inc. Pagosa Springs, Colorado. Online at:
http://www.wildlandhydrology.com/assets/Streambank_erosion_paper.pdf

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
36
Sheely, L. H. July 2002. Load Duration Curves: Development and Application to Data Analysis
for Streams in the Yazoo River Basin, MS. Special Project – Summer 2002. Jackson
Engineering Graduate Program.

Stiles, T.C. 2002. Incorporating hydrology in determining TMDL endpoints and allocations.
Proceedings from the WEF National TMDL Science and Policy 2002 Conference.

United States Department of Agriculture. 1991. Soil survey of Caldwell County, North Carolina.

United States Department of Agriculture, Natural Resources Conservation Service. Soil Data
Mart. Online at:
http://soildatamart.nrcs.usda.gov/Report.aspx?Survey=NC027&UseState=NC

United States Department of Agriculture. Agreement between The State of North Carolina and
The U.S. Department of Agriculture Commodity Credit Corporation concerning the
implementation of the North Carolina Conservation Reserve Enhancement Program
Online at: http://www.fsa.usda.gov/dafp/cepd/crep/NCok.htm

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

United States. Environmental Protection Agency (USEPA). 1993. Guidance Specifying
Management Measures for Sources of Nonpoint Pollution in Coastal Waters. EPA-840-
B-92-002. Washington, DC.

United States. Environmental Protection Agency (USEPA). October 1999. Protocols for
Developing Sediment TMDLs – First Edition. EPA 841-B-99-004. Washington, DC.

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

United States. Environmental Protection Agency (USEPA). Federal Advisory Committee
(FACA). 1998. Draft Final TMDL Federal Advisory Committee Report. April.

United States Environmental Protection Agency (USEPA). 2003. Guidance for 2004 Assessment,
Listing and Reporting Requirements Pursuant to Sections 303(d) and 305(b) of the Clean
Water Act; TMDL-01-03. Online at:
http://www.epa.gov/owow/tmdl/tmdl0103/2004rpt_guidance.pdf

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

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
37

Appendix A. Burke, Mecklenburg, Catawba and Henderson Counties - soils greater
than 1% of county area (NRCS, 1991)
Map symbol
Map
unit
name Description Acres
Perc
ent
Burke FaC2
Fairview sandy clay loam, 8 to 15 percent slopes, moderately
eroded 59,443 18
Burke FaD2
Fairview sandy clay loam, 15 to 25 percent slopes, moderately
eroded 36,573 11.1
Burke RhE Rhodhiss sandy loam, 25 to 45 percent slopes 29,021 8.8
Burke EvE Evard-Cowee complex, 30 to 50 percent slopes, stony 20,802 6.3
Burke FaB2
Fairview sandy clay loam, 2 to 8 percent slopes, moderately
eroded 17,988 5.5
Burke MoE
Meadowfield-Rhodhiss complex, 25 to 60 percent slopes, very
stony 9,294 2.8
Burke CpF Cliffield-Pigeonroost complex, 50 to 80 percent slopes, very stony 9,331 2.8
Burke WoC2
Woolwine-Fairview complex, 8 to 15 percent slopes, moderately
eroded 9,365 2.8
Burke CpE Cliffield-Pigeonroost complex, 30 to 50 percent slopes, very stony 8,791 2.7
Burke AcF
Ashe-Chestnut-Buladean complex, 50 to 95 percent slopes,
extremely stony 8,810 2.7
Burke CvA Colvard sandy loam, 0 to 3 percent slopes, occasionally flooded 9,046 2.7
Burke EvD Evard-Cowee complex, 15 to 30 percent slopes, stony 8,634 2.6
Burke WoD2
Woolwine-Fairview complex, 15 to 25 percent slopes, moderately
eroded 6,682 2
Burke W Water 6,244 1.9
Burke RhD Rhodhiss sandy loam, 15 to 25 percent slopes 6,291 1.9
Burke SoE Soco-Ditney complex, 30 to 50 percent slopes, very stony 5,899 1.8
Burke AsF
Ashe-Cleveland-Rock outcrop complex, 30 to 95 percent slopes,
extremely bouldery 5,444 1.7
Burke EdE Edneytown-Pigeonroost complex, 30 to 50 percent slopes, stony 4,622 1.4
Burke AaA Arkaqua loam, 0 to 2 percent slopes, occasionally flooded 4,624 1.4
Burke DrF Ditney-Unicoi-Rock outcrop complex, 25 to 95 percent slopes 4,719 1.4
Burke EuF Evard-Cowee complex, 50 to 85 percent slopes, rocky 3,898 1.2
Burke CpD Cliffield-Pigeonroost complex, 15 to 30 percent slopes, very stony 3,241 1
Burke CkF Chestnut-Buladean complex, 50 to 95 percent slopes, stony 3,366 1
Mecklenburg CeB2 Cecil sandy clay loam, 2 to 8 percent slopes, eroded 101,192 28.8
Mecklenburg CuB Cecil-Urban land complex, 2 to 8 percent slopes 33,078 9.4
Mecklenburg CeD2 Cecil sandy clay loam, 8 to 15 percent slopes, eroded 29,078 8.3
Mecklenburg MO Monacan loam 21,003 6
Mecklenburg EnB Enon sandy loam, 2 to 8 percent slopes 16,950 4.8
Mecklenburg MeB Mecklenburg fine sandy loam, 2 to 8 percent slopes 15,714 4.5
Mecklenburg IrB Iredell fine sandy loam, 1 to 8 percent slopes 13,656 3.9
Mecklenburg Ur Urban land 12,767 3.6
Mecklenburg PaE Pacolet sandy loam, 15 to 25 percent slopes 10,812 3.1
Mecklenburg HeB Helena sandy loam, 2 to 8 percent slopes 10,451 3
Mecklenburg WkE Wilkes loam, 15 to 25 percent slopes 10,538 3
Mecklenburg WkD Wilkes loam, 8 to 15 percent slopes 10,370 2.9
Mecklenburg EnD Enon sandy loam, 8 to 15 percent slopes 9,532 2.7
Mecklenburg WkB Wilkes loam, 4 to 8 percent slopes 6,881 2
Mecklenburg MeD Mecklenburg fine sandy loam, 8 to 15 percent slopes 4,885 1.4
Mecklenburg MkB Mecklenburg-Urban land complex, 2 to 8 percent slopes 4,482 1.3
Mecklenburg VaB Vance sandy loam, 2 to 8 percent slopes 3,909 1.1
Catawba CmB2 Cecil sandy loam, 2 to 6 percent slopes, eroded 37,745 14.3
Catawba CmC2 Cecil sandy loam, 6 to 10 percent slopes, eroded 36,560 13.8
Catawba HsB2 Hiwassee loam, 2 to 6 percent slopes, eroded 23,287 8.8
Catawba PeE Pacolet soils, 10 to 25 percent slopes 21,258 8
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
38
Map symbol
Map
unit
name Description Acres
Perc
ent
Catawba CnE3 Cecil clay loam, 10 to 25 percent slopes, severely eroded 16,121 6.1
Catawba W Water 12,262 4.6
Catawba CmD2 Cecil sandy loam, 10 to 15 percent slopes, eroded 11,838 4.5
Catawba HsC2 Hiwassee loam, 6 to 10 percent slopes, eroded 11,764 4.4
Catawba Cw Chewacla loam 11,170 4.2
Catawba MgE2 Madison gravelly sandy loam, 10 to 25 percent slopes, eroded 10,137 3.8
Catawba HwC2 Hiwassee clay loam, 6 to 10 percent slopes, eroded 9,831 3.7
Catawba MgC2 Madison gravelly sandy loam, 6 to 10 percent slopes, eroded 7,471 2.8
Catawba CnC2 Cecil clay loam, 6 to 10 percent slopes, eroded 6,278 2.4
Catawba PcC Pacolet gravelly fine sandy loam, 6 to 10 percent slopes 6,180 2.3
Catawba Cy Congaree complex 5,622 2.1
Catawba AsB Appling sandy loam, 2 to 6 percent slopes 4,992 1.9
Catawba PaF Pacolet gravelly sandy loam, 25 to 45 percent slopes 4,902 1.9
Catawba MgB2 Madison gravelly sandy loam, 2 to 6 percent slopes, eroded 4,789 1.8
Catawba HsD2 Hiwassee loam, 10 to 15 percent slopes, eroded 3,607 1.4
Catawba HsE Hiwassee loam, 15 to 25 percent slopes 3,208 1.2
Catawba AsC2 Appling sandy loam, 6 to 10 percent slopes, eroded 2,791 1.1
Henderson AhG Ashe stony sandy loam, 45 to 70 percent slopes 17,734 7.4
Henderson EwF Evard soils, 25 to 45 percent slopes 17,874 7.4
Henderson EdE Edneyville (Edneytown) fine sandy loam, 15 to 25 percent slopes 17,328 7.2
Henderson HyC Hayesville loam, 7 to 15 percent slopes 16,946 7.1
Henderson EdF Edneyville (Edneytown) fine sandy loam, 25 to 45 percent slopes 16,269 6.8
Henderson EwE Evard soils, 15 to 25 percent slopes 15,818 6.6
Henderson AhF Ashe stony sandy loam, 25 to 45 percent slopes 15,548 6.5
Henderson EvC Evard fine sandy loam, 7 to 15 percent slopes 9,500 4
Henderson Co Codorus loam 9,376 3.9
Henderson TuE Tusquitee stony loam, 15 to 25 percent slopes 7,294 3
Henderson HyB Hayesville loam, 2 to 7 percent slopes 6,903 2.9
Henderson HyE Hayesville loam, 15 to 25 percent slopes 6,345 2.6
Henderson TeC Tate fine sandy loam, 7 to 15 percent slopes 5,611 2.3
Henderson BaB Bradson gravelly loam, 2 to 7 percent slopes 5,192 2.2
Henderson EwG Evard soils, 45 to 70 percent slopes 4,862 2
Henderson EdC Edneyville (Edneytown) fine sandy loam, 7 to 15 percent slopes 4,176 1.7
Henderson PoG Porters stony loam, 45 to 70 percent slopes 3,782 1.6
Henderson AhE Ashe stony sandy loam, 15 to 25 percent slopes 3,642 1.5
Henderson BrE Brevard loam, 15 to 25 percent slopes 3,518 1.5
Henderson DeB Delanco (Dillard) loam, 2 to 7 percent slopes 3,257 1.4
Henderson BrC Brevard loam, 7 to 15 percent slopes 3,007 1.3
Henderson FaE Fannin silt loam, 15 to 25 percent slopes 3,116 1.3
Henderson To Toxaway silt loam 3,216 1.3
Henderson BaC Bradson gravelly loam, 7 to 15 percent slopes 2,882 1.2
Henderson PoF Porters stony loam, 25 to 45 percent slopes 2,839 1.2
Henderson TsE Tusquitee loam, 15 to 25 percent slopes 2,750 1.1
Henderson FaC Fannin silt loam, 7 to 15 percent slopes 2,393 1
Henderson Ro Rosman loam 2,375 1
Henderson TeB Tate fine sandy loam, 2 to 7 percent slopes 2,463 1

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
39

Appendix B. Benthic macroinvertebrate results in Long Creek, McAlpine Creek,
Sugar Creek, Little Sugar Creek, Irwin Creek, Henry Fork, and Mud Creek
watersheds
Results for fish monitoring in all watersheds:
Basin Watershed Waterbody Station Date IBI Score IBI Rating
Catawba Henry Fork Henry Fork SR 1916 5/6/1997 46 Good-Fair
Catawba Henry Fork Henry Fork SR 1922 9/28/1998 52 Good
Catawba Little Sugar Little Sugar Cr NC 51 6/30/1997 40 Fair
Catawba Little Sugar Little Sugar Cr NC 51 4/15/1999 42 Good-Fair
Catawba Sugar Cr Sugar Cr SR 1156 6/30/1993 18 Poor
Catawba Sugar Cr Sugar Cr SR 1156 6/30/1997 32 Poor
Catawba Sugar Cr Sugar Cr SR 1156 4/15/1999 28 Poor
French Broad Mud Creek Bat Fork SR 1779 9/16/1997 24 Poor
French Broad Mud Creek Mud Cr SR 1647 9/16/1997 20 Poor
French Broad Mud Creek Clear Cr SR 1513 10/2/2001 44 Good-Fair
French Broad Mud Creek Clear Cr SR 1586 10/2/2001 36 Fair
French Broad Mud Creek Clear Cr SR 1587 10/2/2001 44 Good-Fair
French Broad Mud Creek Bat Fork SR 1779 6/4/2002 14 Poor
French Broad Mud Creek Mud Cr SR 1647 6/4/2002 22 Poor

Results for benthos monitoring in all watersheds:
Basin Watershed Waterbody Location Date Bioclass
Catawba Henry Fork Henry Fork SR 1144 11/16/1983 Fair
Catawba Henry Fork Ut Henry Fork BE Pantasote 6/19/1985 Poor
Catawba Henry Fork Ut Henry Fork AB Pantasote 6/20/1985 Poor
Catawba Henry Fork Henry Fork SR 1124 7/21/1986 Good-Fair
Catawba Henry Fork Ut Henry Fork bel Neuville 2/9/1987 Poor
Catawba Henry Fork Ut Henry Fork I-40 2/9/1987 Good-Fair
Catawba Henry Fork Ut Henry Fork SR 1148 2/9/1987 Good
Catawba Henry Fork Ut Henry Fork US 64 Bypass, 2/9/1987 Not Rated
Catawba Henry Fork Henry Fork SR 1124 7/22/1987 Good-Fair
Catawba Henry Fork HE CR AB Water Intake 4/18/1988 Excellent
Catawba Henry Fork Henry Fork BE HE CR 4/18/1988 Excellent
Catawba Henry Fork Black Fox Ck 4/19/1988 Excellent
Catawba Henry Fork Carswell Br 4/19/1988 Good
Catawba Henry Fork Henry Fork SR 1922 4/19/1988 Excellent
Catawba Henry Fork Ivy Creek SR 1919 4/19/1988 Good
Catawba Henry Fork Rock Creek SR 1915 4/19/1988 Good
Catawba Henry Fork Henry Fork NC 18 4/20/1988 Excellent
Catawba Henry Fork Henry Fork SR 1124 7/10/1989 Good
Catawba Henry Fork Henry Fork SR 1124 8/22/1992 Good
Catawba Henry Fork Henry Fork SR 1124 8/18/1997 Good
Catawba Henry Fork Henry Fork SR 1803 9/12/2001 Good-Fair
Catawba Henry Fork Henry Fork be dam 9/13/2001 Fair
Catawba Henry Fork Henry Fork SR 1124 8/22/2002 Good
Catawba Henry Fork Henry Fork end of SR 1854 4/1/2003 Good-Fair
Catawba Irwin Creek Irwin Creek AB WWTP 11/9/1983 Poor
Catawba Irwin Creek Irwin Creek AB Landfill 10/17/1984 Fair
Catawba Irwin Creek Irwin Creek BE Landfill 10/17/1984 Fair
Catawba Irwin Creek Stewart Creek SR 2050 2/27/1990 Not Rated
Catawba Irwin Creek Irwin Creek SR 2523 2/28/1990 Good-Fair
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
40
Basin Watershed Waterbody Location Date Bioclass
Catawba Irwin Creek Irwin Creek I-77 (West Blvd) 8/18/1992 Poor
Catawba Little Sugar Little Sugar Cr Archdale RD 11/9/1983 Poor
Catawba Little Sugar Little Sugar Cr NC 51 9/19/1992 Poor
Catawba Little Sugar Little Sugar Cr NC 51 8/21/1997 Fair
Catawba Little Sugar Worm Creek SR 1393A 6/24/2002 Not Impaired
Catawba Little Sugar Little Sugar Cr Polk St. 8/19/2002 Poor
Catawba Long Creek Long Creek SR 2042 7/12/1989 Good-Fair
Catawba McAlpine Ck McAlpine Ck NC 521 11/9/1983 Poor
Catawba McAlpine Ck McAlpine Ck SARDIS RD 11/9/1983 Fair
Catawba McAlpine Ck McAlpine Ck AB WWTP 3/26/1987 Poor
Catawba McAlpine Ck McAlpine Ck SARDIS RD 3/26/1987 Fair
Catawba McAlpine Ck McAlpine Ck NC 51 8/19/1992 Fair
Catawba McAlpine Ck McAlpine Ck NC 51 8/21/1997 Fair
Catawba McAlpine Ck McAlpine Ck NC 51 8/19/2002 Fair
Catawba Sugar Cr McCullough Br NC 51 2/27/1990 Poor
Catawba Sugar Cr Sugar Cr SR 1156, BE WWTP 8/18/1992 Poor
Catawba Sugar Cr Sugar Cr SR 1156 8/21/1997 Fair
Catawba Sugar Cr Sugar Cr SR 1156 8/20/2002 Poor
French Broad Mud Creek Mud Creek SR 1508, ab WWTP 9/12/1985 Poor
French Broad Mud Creek Mud Creek SR 1508, be WWTP 9/12/1985 Poor
French Broad Mud Creek Bat Fork nr SR 1809 4/11/1989 Poor
French Broad Mud Creek Bat Fork SR 1779 4/11/1989 Poor
French Broad Mud Creek Bat Fork SR 1807 4/11/1989 Not Rated
French Broad Mud Creek Bat Fork US 176 4/11/1989 Not Rated
French Broad Mud Creek Bat Fork SR 1803 4/12/1989 Poor
French Broad Mud Creek Clear Creek SR 1513 7/7/1992 Poor
French Broad Mud Creek Mud Creek SR 1508, ab WWTP 7/7/1992 Poor
French Broad Mud Creek Mud Creek SR 1508, be WWTP 7/7/1992 Poor
French Broad Mud Creek Clear Creek SR 1586 6/15/1993 Fair
French Broad Mud Creek Clear Creek SR 1587 6/15/1993 Fair
French Broad Mud Creek Clear Creek SR 1591 6/15/1993 Not Rated
French Broad Mud Creek Laurel Fork Wash Freeman Rd 6/15/1993 Good
French Broad Mud Creek Cox Creek SR 1587 6/16/1993 Poor
French Broad Mud Creek
Puncheon
Camp Cr SR 1591 6/16/1993 Not Impaired
French Broad Mud Creek Clear Creek SR 1513 7/8/1997 Poor
French Broad Mud Creek Mud Creek SR 1126 9/8/1997 Not Rated
French Broad Mud Creek Mud Creek SR 1508 9/8/1997 Poor
French Broad Mud Creek Mud Creek SR 1508 9/8/1997 Poor
French Broad Mud Creek Mud Creek SR 1647, 7th Ave 9/8/1997 Poor
French Broad Mud Creek Bat Fork SR 1779 9/9/1997 Fair
French Broad Mud Creek Mud Creek US 25 9/9/1997 Fair
French Broad Mud Creek Bat Fork SR 1779 7/10/2000 Fair
French Broad Mud Creek Bat Fork SR 1809 7/10/2000 Not Rated
French Broad Mud Creek Mud Creek SR 1126 7/11/2000 Not Rated
French Broad Mud Creek Mud Creek SR 1508, ab WWTP 7/11/2000 Fair
French Broad Mud Creek Mud Creek SR 1647, 7th Ave 7/11/2000 Fair
French Broad Mud Creek Clear Creek SR 1513 7/12/2000 Fair
French Broad Mud Creek Clear Creek SR 1586 7/12/2000 Poor
French Broad Mud Creek Mud Creek SR 1508 7/12/2000 Fair
French Broad Mud Creek Devils Fork SR 1006 7/13/2000 Not Rated
French Broad Mud Creek Devils Fork US 64 7/13/2000 Poor
French Broad Mud Creek Mud Creek US 25 7/13/2000 Poor
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
41
Basin Watershed Waterbody Location Date Bioclass
French Broad Mud Creek Clear Creek SR 1591 10/23/2000 Not Rated
French Broad Mud Creek Cox Creek Off SR 1569 10/23/2000 Not Impaired
French Broad Mud Creek Cox Creek SR 1587 10/23/2000 Not Rated
French Broad Mud Creek Mill Creek SR 1586 10/23/2000 Not Rated
French Broad Mud Creek Clear Creek SR 1587 10/24/2000 Good-Fair
French Broad Mud Creek Harper Creek SR 1582 (Clear Ck Rd) 10/24/2000 Excellent
French Broad Mud Creek Laurel Fork Wash Freeman Rd 10/24/2000 Excellent
French Broad Mud Creek Devils Fork SR 1006 10/25/2000 Not Rated
French Broad Mud Creek King Creek US HWY 25 10/25/2000 Not Rated
French Broad Mud Creek Mud Creek SR 1125 10/25/2000 Not Impaired
French Broad Mud Creek Mud Creek SR 1126 10/25/2000 Not Rated
French Broad Mud Creek Clear Creek SR 1513 10/26/2000 Poor
French Broad Mud Creek Devils Fork SR 1006 3/3/2001 Not Rated
French Broad Mud Creek Clear Creek SR 1513 3/13/2001 Fair
French Broad Mud Creek Clear Creek SR 1586 3/14/2001 Poor
French Broad Mud Creek Cox Creek SR 1587 3/14/2001 Not Rated
French Broad Mud Creek Kyle Creek SR 1579 3/14/2001 Not Impaired
French Broad Mud Creek Mill Creek SR 1586 3/14/2001 Not Rated
French Broad Mud Creek Bat Fork be Dunn Cr 7/23/2001 Not Rated
French Broad Mud Creek Bat Fork SR 1779 7/23/2001 Not Rated
French Broad Mud Creek Clear Creek SR 1513 10/3/2001 Fair
French Broad Mud Creek Clear Creek SR 1586 10/3/2001 Poor
French Broad Mud Creek Cox Creek SR 1587 10/3/2001 Not Rated
French Broad Mud Creek Kyle Creek SR 1579 10/3/2001 Not Rated
French Broad Mud Creek Laurel Fork Wash Freeman Rd 10/3/2001 Not Impaired
French Broad Mud Creek Mill Creek SR 1586 10/3/2001 Not Rated
French Broad Mud Creek Mud Creek SR 1125 10/3/2001 Not Impaired
French Broad Mud Creek Mud Creek SR 1126 10/3/2001 Not Rated
French Broad Mud Creek Mud Creek SR 1647, 7th Ave 10/3/2001 Poor
French Broad Mud Creek Devils Fork SR 1006 10/4/2001 Not Rated
French Broad Mud Creek Mud Creek SR 1164 10/4/2001 Fair

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
42

Appendix C. NC DWQ Ambient Monitoring Results for TSS and Turbidity in Long
Creek, McAlpine Creek, Sugar Creek, Little Sugar Creek, Irwin Creek, Henry
Fork, and Mud Creek watersheds
Ambient Chemical Data Station C4040000, LONG CRK AT SR 2042 NR PAW CREEK.
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
01/08/97 6 11
02/17/97 14 28
03/12/97 5 12
04/07/97 28 40
05/13/97 8 7.3
06/04/97 16 32
07/16/97 6 17
08/06/97 14 26
09/04/97 5 4.2
10/21/97 18 37
11/06/97 4 7.9
12/09/97 5 7.7
01/07/98 23 75
02/02/98 4 13
03/04/98 1 10
04/01/98 7 6.6
05/04/98 1 11
06/03/98 7 9.6
07/01/98 64 120
08/24/98 4 5.8
09/08/98 3 8.8
10/28/98 1 2.9
11/16/98 11 35
12/21/98 3 14
01/06/99 9 27
02/08/99 3 10
03/10/99 7 23
04/12/99 4 4.9
05/12/99 5 9.3
06/10/99 8 22
07/13/99 28 43
08/10/99 3 11
09/01/99 1 5.6
10/06/99 1 20
11/08/99 1 45
12/13/99 2 18
01/20/00 61 95
02/02/00 2 50
03/09/00 2 4.7
04/05/00 4 13
05/09/00 4 10
06/14/00 4 3.6
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
43
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
07/06/00 5 8.5
08/03/00 4 11
09/06/00 50
10/09/00 3.8
11/08/00 2 2
12/13/00 5.2
01/11/01 13
02/08/01 1 4.7
04/26/01 18
05/16/01 5 4.6
06/07/01 8.3
07/02/01 100
08/21/01 3 4.9
09/17/01 220
10/18/01 14
11/15/01 2.5 3.8
12/05/01 4.5
01/09/02 21
02/20/02 2.5 4.5
03/11/02 5.2
04/10/02 4.8
05/16/02 9 28
06/06/02 75
07/09/02 12
08/08/02 20 22
09/11/02 9.5
10/01/02 9.8
11/06/02 76 160
12/30/02 13
01/22/03 5.8
02/11/03 6 16
03/13/03 9.6
04/03/03 14
05/22/03 21 170
06/10/03 24
07/10/03 120
08/05/03 22 160
09/11/03 4.5
10/02/03 5.2
11/04/03 4 2.9
12/04/03 4
01/14/04 9
02/09/04 21 40
03/03/04 28

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
44
Ambient Chemical Data Station C9370000, McAlpine Crk at SR 3356 Sardis Rd near
Charlotte
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
02/18/97 6 16
03/17/97 6 11
04/16/97 11 9.4
05/20/97 5 3.6
06/23/97 14
07/30/97 44 80
08/26/97 7 8.1
09/24/97 4 190
10/28/97 26 40
11/20/97 1 5.3
12/30/97 8 25
01/20/98 10 38
02/18/98 17 50
03/12/98 1 15
04/27/98 5 8.6
05/05/98 11 6.6
06/15/98 5 7.3
07/21/98 98 110
08/06/98 4 5
09/15/98 3 6.7
10/13/98 5 16
11/05/98 3 8.3
12/08/98 1 5.7
01/05/99 6 23
02/04/99 12 28
03/04/99 3 12
04/06/99 2 7.8
05/11/99 4 5.8
06/15/99 19 16
07/21/99 2 4.7
08/19/99 3 4.8
09/07/99 4 16
10/18/99 1 4.6
11/18/99 1 2.4
12/14/99 30 80
01/19/00 1 6
02/03/00 3 29
03/06/00 2 7.6
04/04/00 8 5.5
05/10/00 5 5.5
06/22/00 6 4.1
07/25/00 14 23
08/14/00 8 12
09/11/00 9 14
10/17/00 4.1
11/20/00 18
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
45
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
12/12/00 4 4.7
01/04/01 3.8
02/07/01 3.2
04/05/01 2
05/03/01 4.4
06/12/01 4 7.6
07/10/01 12
08/06/01 4.9
09/06/01 12 27
10/02/01 7.2
11/07/01 8.8
12/10/01 4 7.6
01/07/02 37
02/12/02 10
03/06/02 5 16
04/09/02 6.3
05/09/02 5.8
06/04/02 3 8.6
07/10/02 12
08/05/02 8.5
09/03/02 6 22
10/03/02 4.1
11/05/02 7.4
12/03/02 2.5 3.9
01/21/03 7.3
02/06/03 8.6
03/10/03 5 14
04/01/03 19
05/22/03 100
06/12/03 8 14
07/17/03 160
08/04/03 23
09/24/03 9 14
10/20/03 5.3
11/13/03 5
12/22/03 8.1
01/08/04 3.9
02/11/04 11
03/04/04 6 15

Ambient Chemical Data Station C9050000, Sugar Creek at NC 51 at Pineville.
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
1/29/97 84 22
2/11/97 44 29
3/17/97 14 14
4/8/97 10 7.6
5/14/97 1 5.5
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
46
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
6/12/97 85 36
7/21/97 25 14
8/13/97 24
9/18/97 1 3.8
10/28/97 26 37
11/20/97 3 6.9
12/8/97 3 6.7
1/6/98 6 6.2
2/3/98 29 16
3/5/98 4 6.2
4/2/98 27
5/5/98 5 7.6
6/10/98 2000 1100
7/15/98 5 3.7
8/4/98 8 7.4
9/2/98 1 1.9
10/1/98 6 3.9
11/5/98 7
12/2/98 4 2.2
1/4/99 24 50
2/3/99 18 36
3/3/99 4 5.6
4/5/99 9 5.8
5/4/99 7 15
6/3/99 1 4.7
7/1/99 25 19
8/5/99 3 3
9/7/99 6 5.2
10/7/99 1 3
11/3/99 7 11
12/1/99 1 4.2
1/3/00 4 3
2/1/00 22 38
3/1/00 4 7
4/3/00 110 40
5/8/00 8 5.2
6/8/00 5 3.4
7/25/00 5 8.9
8/17/00 2.3
9/20/00 11 17
10/30/00 2.4
11/27/00 15
12/19/00 14 11
1/10/01 7.8
2/6/01 2.3
4/4/01 7
5/2/01 3.6
6/13/01 5 3.6
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
47
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
7/10/01 5.1
8/7/01 6.4
9/5/01 33 33
10/1/01 3.7
11/7/01 4.1
12/3/01 2.5 6.7
1/7/02 80
2/11/02 23
3/5/02 10 22
4/1/02 200
5/8/02 6.9
6/3/02 7 11
7/2/02 160
8/1/02 6.2
9/4/02 6 19
10/2/02 3.3
11/4/02 4.3
12/2/02 2.5 4.1
1/2/03 16
2/5/03 55
3/11/03 12 13
4/1/03 19
5/28/03 24
6/18/03 68 60
7/23/03 15
8/19/03 24
9/25/03 12 13
10/23/03 3.8
11/19/03 30
12/22/03 6.4
1/15/04 5.1
2/12/04 130
3/18/04 5 7.3

Ambient Chemical Data Station C9210000, Little Sugar Creek at NC 51.
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
1/29/97 10 11
2/11/97 19 21
3/17/97 62 26
4/8/97 8 4.9
5/14/97 7 5.3
6/12/97 81 24
7/21/97 6 2.6
8/13/97 3 3.5
9/18/97 9 3.8
10/28/97 11 17
11/20/97 2 4.3
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
48
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
12/8/97 3 3.4
1/6/98 50 33
2/3/98 44 16
3/5/98 1 2.4
4/2/98 9
5/5/98 8 3.8
6/10/98 410 200
7/15/98 1 2.5
8/4/98 2 2.4
9/2/98 6 1.9
10/1/98 21 2.7
11/5/98 8 3.5
12/2/98 2 1.4
1/4/99 13 28
2/3/99 8 15
3/3/99 4 3.2
4/5/99 10 3.5
5/4/99 1 5.7
6/3/99 2 4.1
7/1/99 15 6.7
8/5/99 4 3.2
9/7/99 4 3.5
10/7/99 3 3
11/3/99 6 8
12/1/99 3 3.3
1/3/00 3 2
2/1/00 15 21
3/1/00 1 5.1
4/3/00 45 12
5/8/00 29 3.3
6/8/00 1 3.1
7/25/00 5 6.5
8/17/00 6 2.4
9/20/00 3 5.6
10/30/00 2.2
11/27/00 30
12/19/00 2 6.1
1/10/01 4.1
2/6/01 1.6
4/4/01 4
5/2/01 2.6
6/13/01 4 3
7/10/01 2.9
8/7/01 3.8
9/5/01 11 13
10/1/01 2
11/7/01 4
12/3/01 2.5 7.7
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
49
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
1/7/02 36
2/11/02 9.1
3/5/02 4 11
4/1/02 80
5/8/02 3.8
6/3/02 6 6
7/2/02 23
8/1/02 4
9/4/02 9 9.6
10/2/02 1.7
11/4/02 2.1
12/2/02 2.5 2.9
1/2/03 6.3
2/5/03 14
3/11/03 7 11
4/1/03 24
5/28/03 29
6/18/03 200 140
7/23/03 27
8/19/03 13
9/25/03 6 6.4
10/23/03 5.7
11/19/03 100
12/22/03 4.7
1/15/04 4.2
2/12/04 95
3/18/04 17 35

Ambient Chemical Data Station C8896500, Irwin Creek at Irwin Creek WWTP near
Charlotte.
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
01/22/97 6 7.1
02/20/97 1 6.6
03/19/97 5 5.5
04/17/97 1 3.7
05/19/97 2 1.6
07/22/97 2 1.9
08/14/97 2.3
09/16/97 1 1.6
10/21/97 5 7.9
11/13/97 30 35
12/10/97 110 120
01/08/98 60 150
02/16/98 13 13
03/11/98 22 18
04/29/98 2 3.2
05/20/98 2 2.2
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
50
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
06/23/98 130 6.4
07/22/98 2 5.3
08/10/98 34 40
09/21/98 1 1.9
10/29/98 3 4.4
11/23/98 6 5.9
12/30/98 2 5.8
01/27/99 6 12
02/23/99 2 7.1
03/18/99 4 4.5
04/28/99 42 70
05/24/99 1 2.6
06/28/99 8 17
08/03/99 1 1.2
08/19/99 2 1.7
09/13/99 1 6
10/19/99 1 1.1
11/03/99 1 8.6
12/06/99 1 1.2
01/05/00 4 21
02/21/00 1 4.5
03/16/00 1 1.7
04/18/00 11 26
05/17/00 4 1.6
06/20/00 2 3.9
07/27/00 3 2.2
08/25/00 3 1.3
09/13/00 1.3
10/19/00 3.6
11/29/00 2 4.8
12/28/00 5.8
01/29/01 5.6
02/13/01 5 8
04/23/01 1.7
05/29/01 32 28
06/13/01 45
07/23/01 4
08/23/01 2 1.2
09/18/01 1.2
10/22/01 1.5
11/29/01 2.5
12/17/01 2.6
01/16/02 3.7
02/14/02 3 5.5
03/18/02 45
04/25/02 8.6
05/22/02 7 4.9
06/13/02 1.5
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
51
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
07/01/02 2
08/13/02 4 1.7
09/09/02 1
10/24/02 5.7
11/20/02 3 8.6
01/06/03 4.2
02/13/03 20 5.2
03/04/03 6.8
04/02/03 4.5
05/22/03 270 200
06/12/03 10
07/23/03 17
08/04/03 8 24
09/24/03 20
10/21/03 1.6
11/13/03 2.5 2
12/10/03 200
01/15/04 2.3
02/12/04 190 100
03/04/04 6.8

Ambient Chemical Data Station C4360000, Henry Fork River at SR 1143 Near Brookford.
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
03/13/97 5 5.6
04/03/97 21 4.1
05/01/97 22 12
06/26/97 24 18
07/29/97 40 32
08/21/97 8
09/23/97 8 6.1
10/29/97 10 13
11/24/97 1 5
01/05/98 5 3.5
02/24/98 14 15
03/18/98 12 7
04/23/98 14 9.6
05/19/98 8 6.2
06/09/98 17 13
07/08/98 1 8
08/27/98 2 6.5
09/24/98 32 6.6
10/07/98 36 26
11/09/98 2 2.3
12/17/98 4 3.9
01/14/99 1 3.2
02/16/99 2 3.1
03/24/99 24 13
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
52
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
04/22/99 14 8.4
05/17/99 56 35
06/17/99 31 23
07/19/99 140 70
08/12/99 5 8.6
09/09/99 7 6.5
10/13/99 16 20
11/02/99 42 38
12/02/99 1 2.4
01/04/00 7 4.4
02/09/00 21 16
03/02/00 5 3.2
04/05/00 42 33
05/11/00 4 3.8
06/13/00 40 18
07/06/00 8 16
08/07/00 13 17
09/07/00 22
10/12/00 2.3
11/02/00 3 2.8
12/05/00 2.9
01/09/01 4.7
02/14/01 5 6.8
04/11/01
05/08/01 8 3.6
06/04/01 9.9
07/05/01 190
08/20/01 4 6.2
09/12/01 7.1
10/08/01 27
11/08/01 2.5 5.3
12/04/01 4.1
01/08/02 8.4
02/13/02 7 9.7
03/12/02 5.3
04/08/02 6.3
05/14/02 14 15
06/12/02 12
07/15/02 300
08/06/02 6.1
09/05/02 7.7
10/15/02 45
11/07/02 8 9.6
12/18/02 12
01/08/03 4.4
02/12/03 3 4.1
03/05/03 11
04/03/03 5.4
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
53
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
05/20/03 22 15
06/05/03 36
07/08/03 13
08/13/03 75 65
09/10/03 8.6
10/16/03 9.6
11/10/03 13 7.2
12/08/03 3.4
01/13/04 5.6
02/10/04 24 23
03/02/04 2.4

Ambient Chemical Data Station C4300000, Henry Fork Riv at SR 1124 Nr Henry River.
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
01/07/97 6 17
03/13/97 2 4.1
04/03/97 1 2.7
05/01/97 2 5.2
06/26/97 14 13
07/29/97 17 17
08/21/97 6.9
09/23/97 8 7.4
10/29/97 3 7.2
11/24/97 1 3.1
01/05/98 3 3.2
01/27/98 94 65
02/24/98 6 13
03/18/98 2 2.2
04/23/98 14 5.1
05/19/98 4 6.1
06/09/98 6 9
07/08/98 12 10
08/27/98 3 7.9
09/24/98 1 5.6
10/07/98 9 8
11/09/98 4 2.5
12/17/98 2 2.8
01/14/99 3 1.8
02/16/99 1 3.5
03/24/99 3 3.6
04/22/99 5 5.5
05/17/99 7 7.6
06/17/99 15 20
07/19/99 48 70
08/12/99 10 5.6
09/09/99 5 6.4
10/13/99 10 11
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
54
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
11/02/99 12 17
12/02/99 3 1.6
01/04/00 1 2.2
02/09/00 2 1.1
03/02/00 1 2.5
04/05/00 8 9.4
05/11/00 1 5
06/13/00 4 5.2
07/06/00 2 4.1
08/07/00 6 8
09/07/00 8.9
10/12/00 2.2
11/02/00 1 1.7
12/05/00 1.4
01/09/01 2.5
02/14/01 3 1.8
05/08/01 5 2.6
06/04/01 4.5
07/05/01 150
08/20/01 71 80
09/12/01 10
10/08/01 3.5
11/08/01 3 7
12/04/01 4.4
01/08/02 6.6
02/13/02 8 8.7
03/12/02 4.4
04/08/02 4.8
05/14/02 4 8
06/12/02 6.7
07/15/02 17
08/06/02 6.9
09/05/02 9.8
10/15/02 18
11/07/02 6 8.5
12/18/02 20
01/08/03 4.2
02/12/03 3 3.3
03/05/03 9.5
04/03/03 8.4
05/20/03 16 12
06/05/03 20
07/08/03 6.4
08/07/03 23 18
09/10/03 6.1
10/16/03 7.5
11/10/03 3 2.3
12/08/03 4.3
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
55
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
01/13/04 4
02/10/04 17 10.3
03/02/04 3.1

Ambient Chemical Data Station E2120000, Mud Crk at SR 1508 Nr Balfour.
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
1/2/97 6 4.9
2/26/97 9 6.2
3/13/97 13 5.8
4/24/97 26 14
5/29/97 9 6.3
6/16/97 45 31
7/23/97 12 8.5
8/7/97 10 9.4
9/18/97 9 7.9
10/22/97 4 4.5
11/25/97 2 4.2
12/11/97 3 7
1/14/98 10 13
2/25/98 25 9.8
3/12/98 10 9.9
4/7/98 19 6.8
5/14/98 15 8.4
6/4/98 11 11
7/22/98 30 33
8/26/98 5 7.2
11/30/98 3 2.6
12/14/98 6 7.9
1/7/99 4 5.4
2/25/99 4 5.9
3/18/99 6 6.5
4/8/99 8 6.8
5/26/99 8 9.4
6/17/99 15 14
7/15/99 11 3.9
8/5/99 6 4.3
9/23/99 6 5.8
10/14/99 4 7.4
11/23/99 2 6.3
12/16/99 7 9.1
1/20/00 5 6.2
2/17/00 9 9
3/23/00 21 15
4/13/00 33 24
5/16/00 8 5.2
6/21/00 20
7/11/00 9 6.3
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
56
DATE
TOTAL NONFILTRABLE RESIDUE
MG/L (method 00530)
TURBIDITY, NEPHELOMETRIC
TURBIDITY UNITS NTU (method 82079)
8/16/00 5.3
9/14/00 6.4
10/24/00 2.3
11/8/00 7
12/29/00 7
1/17/01 3.9
4/11/01 11 9.4
5/29/01 19
6/20/01 18
7/2/01 41 50
8/8/01 49
9/20/01 8.3
10/9/01 2 2.5
11/7/01 4
12/19/01 4 4.1
1/29/02 8 7.4
3/21/02 43
4/9/02 8 5.1
5/1/02 79
6/5/02 83
7/10/02 5 7
8/21/02 13
9/4/02 8
10/17/02 16 14
11/6/02 17
12/5/02 36
1/15/03 12 13
2/12/03 3.9
3/18/03 14
4/30/03 20 17
5/28/03 13
6/16/03 50
7/22/03 19 19
8/6/03 70
9/24/03 26
10/8/03 4.6 4.3
11/5/03 12
12/10/03 90
1/21/04 3.2 4
2/11/04 14
3/10/04 4.18

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
57

Appendix D Load Duration Curves for waters in which TMDLs will not be
developed.
McAlpine Creek at Ambient Station C9370000 (1997-2004), and flow at USGS gage #
02146600 (1970-2004).
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent of Days Flow is Equaled or Exceeded
TS
S

l
o
a
d

(
l
b
s
/
d
a
y
)
Reduced Limit Curve, TSS equivelant of 45 NTU
Observed data

Sugar Creek at Ambient Station C9050000 (1997-2004), and estimated flow at
02146381using USGS gage #02146300 (1970-2004).
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent of Days Flow is Equaled or Exceeded
TS
S

l
o
a
d

(
l
b
s
/
d
a
y
)
Reduced Limit Curve, TSS equivelant of 45 NTU
Observed data

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
58
Little Sugar Creek at Ambient Station C9210000 (1997-2004), and estimated flow at
02146530 using USGS gage #02146507 (1970-2004).
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent of Days Flow is Equaled or Exceeded
TS
S

l
o
a
d

(
l
b
s
/
d
a
y
)
Reduced Limit Curve, TSS equivelant of 45 NTU
Observed data

Irwin Creek at Ambient Station C8896500 (1997-2004), and flow using USGS gage
#02146300 (1975-2004).
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent of Days Flow is Equaled or Exceeded
TS
S

l
o
a
d

(
l
b
s
/
d
a
y
)
Reduced Limit Curve, TSS equivelant of 45 NTU
Observed data

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
59
Henry Fork at Ambient Station C4360000 (1997-2004), and estimated flow at the
ambient station (weighted by watershed size) using USGS gage # 02143000 (1970-2004).
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent of Days Flow is Equaled or Exceeded
TS
S

l
o
a
d

(
l
b
s
/
d
a
y
)
Reduced Limit Curve, TSS equivelant of 45 NTU
Observed data

Mud Creek at Ambient Station E2120000 (1997-2004), and using USGS gage #
03446000 (1970-2004).
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent of Days Flow is Equaled or Exceeded
TS
S

l
o
a
d

(
l
b
s
/
d
a
y
)
Reduced Limit Curve, TSS equivelant of 45 NTU
Observed data

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
60

Appendix E Data Sources used to develop the Long Creek TMDL.
The NCDENR’s Geographic Information System (GIS) was used extensively to
watershed characterization. The following is general information regarding the data used
to describe the watershed:

• Ambient chemical monitoring locations: NC DENR Div of Water Quality,
Water Quality Section, 9/30/2000, Ambient Water Quality Monitoring Sites: NC
DENR Div of Water Quality, Water Quality Section, Raleigh, North Carolina.
• Biological monitoring locations: NC DENR Clean Water Management Trust
Fund, NC DENR - Div. of Water Quality, Biological Assessment Unit,
11/15/2000, Benthic monitoring results: NC DENR - Div. of Water Quality,
Biological Assessment Unit, Raleigh, North Carolina.
• Urban area boundary: NC Department of Transportation-GIS Unit, 2002,
Municipal Boundaries - Powell Bill 1999: NC Department of Transportation,
Raleigh, North Carolina.
• County boundaries: information NC Center for Geographic Information &
Analysis, 12/01/1998, Boundaries - County (1:100,000): NC Center for
Geographic Information & Analysis, Raleigh, North Carolina.
• Detailed stream coverage: North Carolina Center for Geographic Information
and Analysis, 4/19/2001, Hydrography (1:24,000): North Carolina Center for
Geographic Information and Analysis, Raleigh, NC.
• Hydrologic Units: USDA, Natural Resources Conservation Service, 12/01/1998,
Hydrologic Units - North Carolina River Basins: USDA, Natural Resources
Conservation Service, Raleigh, North Carolina.
• Land use/Land cover information: Earth Satellite Corporation (EarthSat),
6/12/1998, Statewide Land Cover - 1996: EarthSat, Raleigh, North Carolina.
• NPDES Permitted Facilities: NC DENR Division of Water Quality, Planning
Branch, 10/11/2000, National Pollutant Discharge Elimination System Sites: NC
DENR Division of Water Quality, Planning Branch, Raleigh, North Carolina.
• Roads: NC Department of Transportation - GIS Unit, 9/21/1999, Transportation -
NCDOT Roads (1:24,000): NC Department of Transportation, Raleigh, NC.
• Stream Gaging Stations: NC DENR-Division of Water Resources, 12/01/1998,
Stream Gaging Stations: NC DENR-Division of Water Resources, Raleigh, North
Carolina.
• Streamflow gage data was obtained online from the United States Geological
Survey (USGS) at: http://nc.water.usgs.gov/.
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
61

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Turbidity TMDLs in the Catawba and French Broad Basins January 2005
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Appendix F. NPDES permitted facilities within the Long Creek watershed.

Permit
Number Owner Name Facility Description Waterbody Stream Index
NC0004839 ExxonMobil Refining and Supply Company Kinder Morgan Southeast Terminals - Charlotte Terminal 2 Long Creek 11-120-(0.5)
NC0005185 Magellan Terminals Holdings L P Charlotte II Terminal Long Creek 11-120-(0.5)
NC0046213 Marathon Ashland Petroleum LLC Charlotte Terminal Long Creek 11-120-(0.5)
NC0046892 Motiva Enterprises LLC Charlotte South Terminal Long Creek 11-120-(0.5)
NC0086002 Livingstone Coating Corporation Livingstone Coating Corporation Long Creek 11-120-(2.5)
NCG080584 McKenzie Tank Lines Inc McKenzie Tank Lines Inc - Charlotte Long Creek 11-120-(0.5)
NCG080652 USF Holland Inc USF Holland Inc - Charlotte Long Creek 11-120-(0.5)
NCG140053 Concrete Supply Co Concrete Supply Co-Croft Plt Long Creek 11-120-(0.5)
NCS000037 Clariant Corporation Mount Holly East (MHE) Facility Long Creek 11-120-(0.5)
NCG020089 Ogelbay Norton Specialty Minerals Oglebay Norton Spcty Minerals Dixon Br 11-120-1
NCG030434 Torque Traction Int Tech Inc Torque Traction Int Tech Inc Dixon Br 11-120-1
NCG160169 Rea Contracting LLC Rea Contracting LLC - North Mecklenburg Plant 078 Dixon Br 11-120-1
NC0021962 CITGO Petroleum Corporation Paw Creek Terminal Gum Br 11-120-5
NC0022187 Motiva Enterprises LLC Paw Creek Terminal Gum Br 11-120-5
NC0031038 Colonial Pipeline Company Paw Creek Terminal Gum Br 11-120-5
NC0032891 Kinder Morgan Southeast Terminals LLC KMST Charlotte Terminal Gum Br 11-120-5

List of individual permitted facilities including permit limits for TSS or turbidity in Long Creek watershed.
Permit
Number Facility Name Flow Limit
Turbidity
Limit (NTU)
Daily Max
(TSS mg/L)
NC0004839 Kinder Morgan Southeast Terminals - Charlotte Terminal 2 45
NC0005185 Charlotte II Terminal
NC0046213 Charlotte Terminal 45
NC0046892 Charlotte South Terminal 45
NC0086002 Livingstone Coating Corporation 0.0216
NC0021962 CITGO Petroleum Corporation/ Paw Creek Terminal 45
NC0022187 Motiva Enterprises LLC/ Paw Creek Terminal 45
NC0031038 Colonial Pipeline Company/ Paw Creek Terminal 45
NC0032891
Kinder Morgan Southeast Terminals LLC/ KMST
Charlotte Terminal 50 45

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
63
List of facilities with General Permits including permit limits for TSS or turbidity in Long Creek watershed.
Permit
Number Facility Name
Turbidity
Limit (NTU)
TSS Daily Max
(TSS mg/L)
Annual Max
Measurement
NCG020089 Ogelbay Norton Specialty Minerals 50 100
NCG030434 Torque Traction Int Tech Inc 100
NCG160169 Rea Contracting LLC- North Mecklenburg Plant 078 100
NCG080584 McKenzie Tank Lines Inc - Charlotte 100
NCG080652 USF Holland Inc - Charlotte 100
NCG140053 Concrete Supply Co-Croft Plt 30

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
64

Appendix G. Methodology for developing the Load Duration Curve

The load duration curve method is based on comparison of the frequency of a given flow
event with its associated water quality load. In the case of applying the NTU criteria, a
correlation is necessary between NTU and TSS to allow for calculation of a load in mass
per time units. Data from the Long Creek ambient station (Station C4040000) was used
in this TMDL resulted in the below equation:

TSS concentration (mg/L) = (0.2986* Turbidity (NTU) + 2.3061)
R2 = 0.60

A LDC can be developed using the following steps:

1. Plot the Flow Duration Curve, Flow vs. % of days flow exceeded.
2. Develop TSS-turbidity correlation.
3. Translate turbidity values to equivalent TSS values using the linear regression
equation from the correlation.
4. Translate the flow-duration curve into a LDC by multiplying the water quality
standard (as equivalent TSS concentration), the flow and a units conversion factor;
the result of this multiplication is the maximum allowable load associated with each
flow.
5. Graph the LDC, maximum allowable load vs. percent of time flow is equaled or
exceeded.
6. Water quality samples, expressed as estimated TSS values, are converted to loads
(sample water quality data multiplied by daily flow on the date of sample).
7. Plot the measured loads on the LDC

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
65
Appendix H. Development of Regression Equation
Results of the regression analysis of total suspended solids load on flow frequency, Long
Creek TSS and turbidity data, 1997-2004 are summarized below.
SUMMARY OUTPUT

Regression Statistics
Multiple R 0.794845
R Square 0.631778
Adjusted R Square 0.626199
Standard Error 0.861016
Observations 68

ANOVA
df SS MS F Significance F
Regression 1 83.95031 83.95031 113.2399 5.86E-16
Residual 66 48.92905 0.741349
Total 67 132.8794

Coefficients
Standard
Error t Stat P-value Lower 95% Upper 95%
Intercept 7.671917 0.262339 29.24431 1.69E-39 7.148141 8.195693
X Variable 1 -4.54411 0.427021 -10.6414 5.86E-16 -5.39668 -3.69154

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,

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
66
where sy is the sample standard deviation of the y values, and t
-2 is the Student’s t


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

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
nss .

Explanation taken from NCDENR, 2004c.

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
67

Appendix I. Background TSS conditions in Long Creek as a function of percent of
flow exceedence.

y = 1136.3e-3.8583x
R2 = 0.7015
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
0% 10% 20% 30% 40% 50% 60% 70% 80% 90%
Percent of Days Flow is Equaled or Exceeded
TS
S

l
o
a
d

(
l
b
s
/
d
a
y
)

.
Reduced Limit Curve, TSS equivelant of 45 NTU
NCDWQ TSS Observed
NCDWQ TSS Estimated
Background Conditions

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
68

Appendix J. Public Notification of Public Review Draft of Long Creek Turbidity
TMDL.

Long Creek, Catawba River Basin

Now Available Upon Request

Long Creek Turbidity Total Maximum Daily Load

Is now available upon request from the North Carolina Division of Water Quality. This
TMDL study was prepared as a requirement of the Federal Water Pollution Control Act,
Section 303(d). The study identifies the sources of pollution, determines allowable loads
to the surface waters, and suggests allocations for turbidity.

TO OBTAIN A FREE COPY OF THE TMDL REPORT:

Please contact Mr. Brian Jacobson [phone], extension 552 or write to:

Mr. Brian Jacobson
Water Quality Planning Branch
NC Division of Water Quality
1617 Mail Service Center
Raleigh, NC 27699-1617

Interested parties are invited to comment on the draft TMDL study by December 17, 2004.
Comments concerning the reports should be directed to Mr. Brian Jacobson at the above
address. The draft TMDL is also located on the following website:
http://h2o.enr.state.nc.us/tmdl

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
69

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
70

Turbidity TMDLs in the Catawba and French Broad Basins January 2005
71
Appendix K. Responsiveness Summary to TMDL Report Comments.

Responsiveness Summary for “Total Maximum Daily Loads (TMDLs) for Turbidity in
Long Creek, McAlpine Creek, Sugar Creek, Little Sugar Creek, Irwin Creek, Henry Fork,
and Mud Creek in North Carolina”

NC Division of Water Quality
January 6, 2005

Comments from specified organizations are in italics as they appear in the delivered
documents. DWQ’s response follows in plain text.

COMMENT: Will there be a public meeting for the Draft Catawba French Broad Basin
TMDL report after the comment period? (Bob Holman, Environmental Operations
Engineer, North Carolina Department of Transportation, Division of Highways,
Environmental Operations Section)

RESPONSE: No. The Division of Water Quality is not conducting public meetings in
TMDL watersheds of the size and scope of Long Creek.

COMMENT: The NC Department of Transportation appreciates the opportunity to
review and comment on the draft Turbidity TMDLs for the subject streams in the
Catawba and French Broad River basins. The protection of surface water quality is a
very important component of our department’s mission to provide our citizens with safe
transportation facilities in an environmentally responsible manner.

Since 1974 the Department has implemented a delegated Erosion and Sediment Control
Program. We continually strive to improve this program through comprehensive water
quality monitoring and the implementation of proven erosion control BMPs. The
Department invests in an ongoing research program to develop innovative erosion
control BMPs in partnership with local governments, such as Mecklenburg County, and
leading university researchers.

Attached is a brief summary of some of the innovative erosion control activities we are
implementing within the Long Creek TMDL watershed and in other locations across the
state. We respectively request that this summary be included within Section 6.0
Implementation of the TMDL report.

The NCDOT began implementation of a delegated Erosion and Sediment Control
Program in 1974. The program continually strives to improve its effectiveness through
water quality monitoring, research, and the development of innovative erosion control
BMPs. Presently, the program is evaluating the water quality impact of road
construction in the Catawba River Basin through three related projects. The first project
involves detailed water quality monitoring of the Long Creek Watershed, the second is
evaluating various methods to reduce erosion and off-site sediment movement, and the
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
72
third addresses sediment loading from secondary road construction activities. The first
two projects are being conducted in Mecklenburg County and the third project noted is
located in Burke County.

In conjunction with Mecklenburg County’s S.W.I.M Program, the first project is
collecting detailed water quality data at 15 locations along a portion of Long Creek.
These data are being collected in 15 minutes intervals to determine in “real time” if
selected water quality parameters, with an emphasis on turbidity, are being violated. If a
problem is detected, the monitoring system includes the capability to send alerts to
Mecklenburg County’s Water Quality Program and the NCDOT, such that staff can
quickly respond to determine and correct the source of the water quality violation. The
project has been in place for almost two years with onsite management provided by
Mecklenburg County.

The second project is comparing the effectiveness of various innovative erosion control
systems which include the use of polyacrylamides, rolled erosion control products, and
bonded fiber matrix hydromulching. Testing of these BMPs is taking place on a segment
of the Charlotte I-485 Outer Loop. These systems are being installed, evaluated, and
modified if needed to improve their effectiveness. The project has been active for over a
year and is directed by Drs. Richard McLaughlin and Greg Jennings of North Carolina
State University.

The third project is on a secondary road bridge construction project in Burke County.
Single stage samplers have been installed up and downstream to monitor pre, during,
and post construction TSS and turbidity (NTU) levels. A crest gage has been installed to
monitor stream stage levels to develop a stage/discharge relationship. Sediment loading
values have been developed thus far for the pre-construction phase. Dr. Garry Grabow
with North Carolina State University has provided general project oversight. The
NCDOT has approximately 30 other sites across the state also under similar
investigation. (Don Lee, Chief, Roadside Environmental Unit, North Carolina
Department of Transportation)

RESPONSE: DWQ appreciates the additional information on water quality
improvement projects and BMP implementation. This information will be included in
Section 6.0 as requested.

COMMENT: The City of Charlotte, Storm Water Services Division has obtained and
reviewed the draft Turbidity TMDL dated November 2004 for creeks in Charlotte and
Mecklenburg County. We have the following comments on the draft report.

Pages 33 and 34 of the report reference the responsible agency and jurisdiction
regarding addressing water quality impairments in Mecklenburg County.

• The City of Charlotte is the responsible jurisdiction for streams within the City’s
jurisdiction. This jurisdiction encompasses 70% of Mecklenburg County and
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
73
includes the City’s Extra-Territorial Jurisdiction (ETJ). Certain programs to
address water quality impairments are conducted in partnership with
Mecklenburg County. However, the City’s water quality program, roles,
initiatives, and responsibility level is separate from that of Mecklenburg County.

• The City of Charlotte, not Mecklenburg County, is the responsible agency for the
sediment and erosion control program throughout the City and its ETJ. Although
the City and County programs are similar, questions about the City’s sediment
and erosion control program and related initiatives should be directed to Dave
Weekly of the Charlotte Land Development Services Division.

• The draft report states that the City of Charlotte was contacted regarding the
Long Creek Turbidity TMDL. No staff person of the City has been coordinated-
with or contacted regarding this report or of the development of this TMDL. It is
important that every effort be made by the Division of Water Quality to notify and
coordinate with the appropriate City of Charlotte staff member regarding the
development of any TMDL or other related regulatory activities affecting streams
in the City’s jurisdiction and ETJ. (Daryl Hammock, PE, Water Quality Program
Manager, City of Charlotte, Storm Water Services)

RESPONSE: Pages 34 and 35 have been changed to reflect the comments outlined by the
City of Charlotte. It is the desire of the Division of Water Quality to work closely with all
local and state agencies responsible in managing water quality to address such issues as
outlined in the TMDL Report. The City of Charlotte is correct; future efforts to coordinate
will be improved.
Turbidity TMDLs in the Catawba and French Broad Basins January 2005
74

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