Muddy_Creek_Addendum_TMDL_Final

Addendum to the 2011Muddy Creek TMDL
for Impaired Segments in the
Muddy Creek Watershed,
North Carolina

Final Report
May 24, 2016

[Waterbody ID: (12-94-0.5)b2b]

Yadkin Pee Dee River Basin

Submitted by:
NC Department of Environmental Quality
Division of Water Resources
1611 Mail Service Center
Raleigh NC 27699-1611

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Introduction
As reported in the 2010 303(d) list, the North Carolina Division of Water resources (DWR) first identified
turbidity impairments in Muddy Creek within the Yadkin Pee Dee River Basin from State Road (SR)
2995 to a point 0.8 mile upstream of mouth in 2008. The associated assessment unit (AU) for the
impaired section of the creek was 12-94-(0.05)c. This impaired section is shown in “green” below in
Figure 1. As required by the Clean Water Act (CWA), the DWR developed a Total Daily Maximum Load
(TMDL) for Turbidity for Muddy Creek. The TMDL was approved by the United States Environmental
Protection Agency (EPA) Region 4 on November 17, 2011. The approved TMDL document is posted at
http://portal.ncdenr.org/c/document_library/get_file?uuid=21f0fcc5-020f-4c37-9e34-
f9da0e7dbd14&groupId=38364.
The Division identified an additional impairment for Turbidity on Muddy Creek from Silas Creek to SR
2995 on the 2014 303(d) list. The associated assessment unit for this impaired section is 12-94-(0.5)b2b.
The newly identified impaired section is located directly above the original impairment and is shown in
“red” in Figure 1. This document focuses on this impaired section in Muddy Creek and represents an
addendum to the approved TMDL document.
Watershed Description
This TMDL addendum covers the Muddy Creek watershed in theYadkin Pee Dee River Basin. The
watershed encompasses the North Carolina counties of Stokes, Forsyth and Davidson and covers 256
square miles (Figure 1). The 2011 National Land Cover Dataset (NLCD) indicates the watershed is
predominantly covered by developed lands (52%) and forested lands (30%) (Figure 2 & Appendix Table
A1). Pasture and grasslands covers only 15%. Of the developed lands, 32% is comprised of open spaces,
which includes large lot single family housing units, parks, golf courses, and vegetation planting in
developed settings. The developed open spaces is appeared to be expanded by 6% since 2006 (Appendix
Table A1).
Point sources in the watershed are all stormwater. The Village of Clemmons (NCS000247), Winston
Salem (NCS000410) and the NCDOT (NCS000250) are all Municipal Separate Storm Sewer System
(MS4) stormwater permittees in the Muddy Creek Watershed. These permittees were all named in the
original TMDL.

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Figure 1. Muddy Creek Watershed showing addendum impairment section in Muddy Creek and urban
areas across the watershed.
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Figure 2. Land use distribution in the Muddy Creek Watershed, showing addendum impairment section.
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Documentation of Impairment
The identified assessment unit is listed in Category 5 of the 2014 North Carolina Integrated Report for
high turbidity. Waters within this classification, according to 15A NCAC 02B.0221 (Fresh Surface Water
Quality Standards for Class C Waters), must meet the following water quality standard for turbidity in
order to meet their designated use:
“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 shall not 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 shall be in full
compliance with all specifications governing the proper design, installation, operation, and maintenance
of such BMPs.”
Data was collected through the NC Ambient Monitoring System station Q2600000 (Figure 1) for the
2014 303(d) assessment and are included in Appendix B and are summarized in Table 1. As per the
assessment numeric criteria for NC streams, greater than 10% of the measured turbidity exceeded the
evaluation level (50 NTU) with greater than or equal to 90% confidence. Consequently, Muddy Creek is
identified as impaired for turbidity from Silas Creek to SR 2995 (red section in Figure 1).
Table 1. Turbidity measurement from 2008 through 2012 in Muddy Creek.
Station Number of
Samples (N)
N>Evaluation Level
(EL=50 NTU)
%>EL Significant Level (%)
Q2600000 57 11 19.3 97.56

Source Assessment
Turbidity is a measure of cloudiness of water, which can be increased due to silt and clay from the
watershed stream erosion, organic detritus from stream bank vegetation, wastewater, and phytoplankton
growth. Potential sources of turbidity from nonpoint sources are forests, agricultural lands, land
disturbance, urban runoff, and stream channel erosion.
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Surface runoff is the main carrier of sediments from forests and agricultural land. Normally, runoff
flowing through undisturbed forest carries insignificant amounts of sediments. Runoff flowing through
agricultural land can carry a substantial amount of sediments, depending on erodibility of soils, types of
agricultural practices, crop type and density, rainfall intensity, and existence and type of agricultural
BMPs. Urbanization also increases the amount of sediment transported to receiving waters. Impervious
urban landscapes like roads, bridges, parking lots, and buildings prevent rainwater from percolating into
the ground. In impervious areas, rainwater remains above the land surface, gathers sediments and solid
materials, and runs off in large amounts.
TMDL Reductions
The required watershed reductions specified in the EPA approved TMDL for Turbidity for Muddy Creek
and the Yadkin River on November 17, 2011 are expected to achieve water quality standards in the
addendum-impaired section of the creek. Regular monitoring at the ambient station, Q2600000, will
continue to provide a measure of progress towards meeting TMDL goals.
As a result of the original TMDL Winston-Salem has prepared and is implementing a water quality
recovery program in accordance with its NPDES storm water permit. This recovery program includes the
watershed in which the addendum assessment unit is located. The program is available from Storm Water
Permitting Unit, Division of Energy, Mineral and Land Resources (DEMMLR).
DWR may reevaluate the need for a TMDL for the creek if the required reduction is determined to be
insufficient.
Public Participation
The 2011 TMDL for Turbidity for Muddy Creek and the Yadkin River was publicly noticed for a 30-day
period. Notice was published through the DWQ Modeling and TMDL unit (now known as the DWR
Modeling and Assessment Branch) website, through the Modeling and TMDL unit listserv, through the
DWQ events calendar, and through the Water Resources Research Institute (WRRI) listserv of North
Carolina State University.
A draft of this addendum to the TMDL for Turbidity for Muddy Creek and the Yadkin River was publicly
noticed for comments through the DWR TMDL listserv, Water Resources Research Institute listserv, and
the DWR Public Events Calendar. A copy of the public notice is included in Appendix C. The addendum
was made available on DWR’s website at http://portal.ncdenr.org/web/wq/ps/mtu/tmdl/tmdls. The
public comment period lasted for a minimum of 30 days, April 19 through May 23, 2016. NCDWR did
not receive comments by the end of the comment period.
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Appendix A: Land Cover Data

Appendix Table A1. Land use changes in the Muddy Creek Watershed, Yadkin Pee Dee River Basin,
from 2006 to 2011.
Land use Types 2006 Land use Data1 2011 Land use Data2
Area (sq. mi) % Area (sq. mi) %
Barren Land 0.3 0 0.13 0
Cultivated Crops 2.3 1 0.27 0
Deciduous Forest 28.2 11 60.77 24
Developed, High Intensity 6.7 3 5.41 2
Developed, Low Intensity 53.5 21 33.38 13
Developed, Medium Intensity 14.2 6 14.10 6
Developed, Open Space 65.2 26 80.67 32
Emergent Herbaceous Wetland 0 0 0.03 0
Evergreen Forest 26.8 10 10.19 4
Grassland/Herbaceous 1.2 0 10.37 4
Mixed Forest 13.8 5 1.16 0
Open Water 1.4 1 1.46 1
Pasture/Hay 37.3 15 33.41 13
Scrub/Shrub 2.7 1 2.38 1
Woody Wetlands 1.7 1 1.82 1
1. 2006 land use data was used to develop a TMDL for Turbidity for Muddy Creek, which was
approved by the EPA Region 4 on November 17, 2011.
2. 2011 land use data is used to develop this addendum TMDL for Turbidity for Muddy Creek.

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Appendix B: NC AMS

Appendix Table B1. Turbidity data used to assess impairment on Muddy Creek for the 2014 303(d) list.
Station Date Turbidity (NTU)
Q2600000 1/30/2008 7.9
Q2600000 2/27/2008 9.5
Q2600000 3/25/2008 5.9
Q2600000 4/16/2008 6.9
Q2600000 5/29/2008 7.2
Q2600000 6/23/2008 65
Q2600000 7/28/2008 9.3
Q2600000 8/27/2008 310
Q2600000 9/25/2008 5.3
Q2600000 10/23/2008 3.6
Q2600000 12/1/2008 40
Q2600000 12/18/2008 23
Q2600000 1/20/2009 8.8
Q2600000 2/19/2009 20
Q2600000 3/26/2009 8.4
Q2600000 5/5/2009 40
Q2600000 6/4/2009 25
Q2600000 6/29/2009 6.9
Q2600000 7/22/2009 20
Q2600000 8/25/2009 6.4
Q2600000 9/21/2009 5.4
Q2600000 10/21/2009 3.9
Q2600000 11/30/2009 5.4
Q2600000 12/10/2009 39
Q2600000 1/19/2010 20
Q2600000 2/3/2010 100
Q2600000 3/16/2010 13
Q2600000 4/29/2010 3.8
Q2600000 5/18/2010 23
Q2600000 6/16/2010 50
Q2600000 8/3/2010 6.8
Q2600000 9/1/2010 12
Q2600000 9/30/2010 110
Q2600000 10/27/2010 290
Continued on next page:
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Appendix Table B1 Continued:
Station Date Turbidity (NTU)
Q2600000 11/16/2010 5.1
Q2600000 12/14/2010 5
Q2600000 1/12/2011 3.7
Q2600000 2/10/2011 7.6
Q2600000 3/17/2011 7.8
Q2600000 5/4/2011 140
Q2600000 5/17/2011 75
Q2600000 6/20/2011 6.5
Q2600000 7/20/2011 70
Q2600000 8/31/2011 2.9
Q2600000 9/6/2011 160
Q2600000 10/6/2011 3.1
Q2600000 11/21/2011 11
Q2600000 12/15/2011 5.1
Q2600000 2/28/2012 8.3
Q2600000 4/3/2012 5.6
Q2600000 4/23/2012 5.6
Q2600000 5/10/2012 230
Q2600000 6/27/2012 3.6
Q2600000 8/29/2012 220
Q2600000 9/27/2012 3.3
Q2600000 11/5/2012 1.9
Q2600000 12/4/2012 2.8
Maximum 310
Minimum 1.9
Average 40.27
% Result above standard 19.30
Binominal Probability of Exceeding the Standard 0.97

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Appendix C: Public Notice

Public Comment Period for the Addendum to the 2011 Muddy
Creek TMDL

Event Description
Now Available for Public Comment
2016 Addendum to the 2011 Muddy Creek TMDL for Impaired Segments in the Muddy Creek
Watershed, North Carolina

April 19, 2016

This Draft Addendum TMDL report was prepared as a requirement of the Federal Water
Pollution Control Act, Section 303(d). Interested parties are invited to comment on the Draft
Addendum TMDL report by May 23, 2016. Comments and questions concerning the report
should be directed to Narayan Rajbhandari at [e-mail].

The draft TMDL can be downloaded from the following website:
https://ncdenr.s3.amazonaws.com/s3fs-
public/Water%20Quality/Planning/TMDL/Draft%20TMDLs/Muddy_Creek_AddendumTMDL_
Draft_2016.pdf