north_buffalo_tmdl_final_report

Fecal Coliform Total Maximum Daily Load for the
Upper North Buffalo Creek Watershed
City of Greensboro, Guilford County

Final Report

January 2004 (Approved April 2004)

Cape Fear River Basin

Prepared by:

City of Greensboro NC Department of Environment
Department of Water Resources and Natural Resources
Stormwater Management Division Division of Water Quality
201 North Greene Street Water Quality Section – Planning Branch
Greensboro, NC 27402-3136 1617 Mail Service Center
[phone] Raleigh, NC 27699-1617
[phone]
Final Report North Buffalo Creek Fecal Coliform TMDL Summary Sheet
i
SUMMARY SHEET
Total Maximum Daily Load (TMDL)
North Buffalo Creek at and above Summit Avenue

1. 303(D) List Information

State: North Carolina

County: Guilford

River Basin: Cape Fear River Basin

Watershed: Upper North Buffalo Creek

303(d) Listed Waters:

Name of Stream Description Class Index # 8 Digit CU Miles
North Buffalo Creek From source to above WWTP C NSW 16-11-14-1a 03030002 8.7

NC DWQ Subbasin: 03-06-02

8 Digit Cataloging Unit: 03030002

Area of Impairment: 8.7 miles

WQS Violated: Fecal Coliform

Pollutant of Concern: Fecal Coliform

Sources of Impairment: Point and nonpoint sources within the watershed

2. Public Notice Information

Form of Public Notification: A TMDL stakeholder group was formed to provide
guidance and comment throughout the TMDL development process. The stakeholder
group was comprised of public and private sector resource professionals potentially
affected by the TMDL and/or having a general interest in water quality protection. Five
formal stakeholder meetings were held over the course of the TMDL development
process. [Additional public notification efforts will include an advertisement in the local
newspaper, etc.]

Did notification contain specific mention of TMDL proposal? _____

Were comments received from the public? _____

Was a responsiveness summary prepared? _____
Final Report North Buffalo Creek Fecal Coliform TMDL Summary Sheet
ii

3. TMDL Information

Critical condition: Highest predicted instream fecal coliform concentrations occur
during wet weather periods preceded by a period of dry weather. The period of highest
risk to public health is during dry weather periods in the summer when recreational use of
the waters is greatest and human sources of bacterial contamination dominate watershed
loads.

Seasonality: A continuous simulation model during the period August 1998 through
August 2001 (period of record for stream flow gage data and precipitation data in the
watershed) includes seasonal fluctuations in fecal coliform loading.

Development tools: WinHSPF version 2.0.6

4. TMDLs

Loading allowed at critical conditions reflective of both wet and dry weather
conditions:

Wasteload Allocation (WLA): 2.73E+11 counts/day
Load Allocation (LA): 1.25E+12 counts/day
Margin of Safety (MOS): More stringent geometric mean target of 180 counts/100mL,
as opposed to the 200 counts/100mL WQS; conservative
modeling assumptions.
TMDL (WLA+LA+MOS): 1.52E+12 counts/day

TMDL Component
(wet and dry weather conditions) TMDL Allocation Category Fecal Coliform Load Reductions
Wasteload Allocation (WLA) MS4
(NCS000248) 1 96%
Load Allocation (LA) Nonpoint Sources 2 93%
Wasteload Allocation (WLA) Cone Mills WWTP
(NC0000876 ) 3 N/A
Notes:
1 MS4 = Municipal Separate Storm Sewer System. This allocation category covers individual sources contributing
fecal coliform loads which are transported to the receiving stream via the City of Greensboro’s NPDES permitted stormwater conveyance system. 2 This allocation category covers individual sources whose loads are delivered to the receiving stream via modes not associated with the MS4.
3 The Cone Mills WWTP ceased discharging treated industrial/domestic wastewater into North Buffalo Creek during
the latter portion of the TMDL simulation period, therefore a load reduction is not applicable.

Final Report North Buffalo Creek Fecal Coliform TMDL Summary Sheet
iii
Loading allowed at critical conditions during dry weather conditions:

Wasteload Allocation (WLA): 1.98E+10 counts/day
Load Allocation (LA): 1.10E+11 counts/day
Margin of Safety (MOS): More stringent geometric mean target of 180 counts/100mL,
as opposed to the 200 counts/100mL WQS; conservative
modeling assumptions.
TMDL (WLA+LA+MOS): 1.30E+11 counts/day

TMDL Component
(dry weather conditions) TMDL Allocation Category Fecal Coliform Load Reductions
Wasteload Allocation (WLA) MS4
(NCS000248) 1 72%
Load Allocation (LA) Nonpoint Sources 2 70%
Wasteload Allocation (WLA) Cone Mills WWTP
(NC0000876 ) 3 N/A
Notes:
1 MS4 = Municipal Separate Storm Sewer System. This allocation category covers individual sources contributing
fecal coliform loads which are transported to the receiving stream via the City of Greensboro’s NPDES permitted stormwater conveyance system. 2 This allocation category covers individual sources whose loads are delivered to the receiving stream via modes not associated with the MS4.
3 The Cone Mills WWTP ceased discharging treated industrial/domestic wastewater into North Buffalo Creek during
the latter portion of the TMDL simulation period, therefore a load reduction is not applicable.

Final Report North Buffalo Creek Fecal Coliform TMDL Table of Contents
iv
TABLE OF CONTENTS

List of Tables .....................................................................................................................vi
List of Figures .................................................................................................................vii
Acronyms and Abbreviations ............................................................................................ix
Executive Summary............................................................................................................x
1.0 Introduction................................................................................................................1
1.1 BACKGROUND...........................................................................................................1
1.2 Watershed Description.............................................................................................3
1.3 Subwatersheds..........................................................................................................4
1.4 Population Estimates................................................................................................5
1.5 Existing Land Use / Land
Cover..............................................................................6
1.6 Age of Residential
Development.............................................................................9
1.7 Impervious Surfaces...............................................................................................10
1.8 Monitoring Stations ...............................................................................................11
1.9 Observed
Instream Fecal Coliform Data ...............................................................12
2.0 Source Assessment ...................................................................................................17
2.1 Point Source Assessment.......................................................................................17
2.1.1 Cone Mills WWTP .........................................................................................17
2.1.2 Illicit Discharges From Greensboro’s Stormwater Conveyance System........18
2.2 Nonpoint Source
Assessment ................................................................................21
2.2.1 Pets..................................................................................................................21
2.2.2 Sanitary Sewer Line



Exfiltration....................................................................23
2.2.3 Sewer System Overflows................................................................................24
2.2.4 Failing Septic Systems....................................................................................26
2.2.5 Waterfowl .......................................................................................................28
2.2.6 Other Sources..................................................................................................32
3.0 Modeling Approach.................................................................................................33
3.1 Model Selection .....................................................................................................33
3.2 Model Setup...........................................................................................................33
3.2.1 Subwatersheds and



Stream



Reaches ..............................................................34
3.2.2 Meteorological Data........................................................................................34
3.2.3 Model Simulation Period................................................................................35
3.2.4 Land



Use/Land



Cover and Impervious Surfaces............................................35
3.2.5 Water Withdrawals .........................................................................................35
3.3 Fecal
Coliform Source Representation..................................................................35
3.3.1 Cone Mills WWTP NPDES



Discharge ..........................................................36
3.3.2 Illicit



Discharges From Stormwater Conveyance System..............................36
3.3.3 Pets..................................................................................................................36
3.3.4 Exfiltrating Sanitary Sewer



Lines...................................................................37
3.3.5 Sanitary Sewer Overflows ..............................................................................37
3.3.6 Failing Septic Systems....................................................................................37
3.3.7 Waterfowl .......................................................................................................37
3.3.8 Other Sources..................................................................................................38
3.4 Model
Calibration
and Confirmation.....................................................................38
3.4.1 Hydrologic Calibration ...................................................................................39
Final Report North Buffalo Creek Fecal Coliform TMDL Table of Contents
v
3.4.2 Water Quality Calibration...............................................................................43
4.0 Total Maximum Daily Load....................................................................................46
4.1 Instream Water
Quality
Target ..............................................................................47
4.1.1 Dry Weather TMDL Target............................................................................48
4.1.2 All Weather Conditions



TMDL Target ..........................................................49
4.1.3 TMDL Watershed



Compliance Point.............................................................49
4.2 Margin of Safety and Model Uncertainty..............................................................49
4.3 Seasonal Variation .................................................................................................50
4.4 Predicted
Existing Water Quality Conditions........................................................50
4.4.1 Predicted Existing Water Quality Under All Weather Conditions.................50
4.4.2 Predicted Existing Water Quality Under Dry Weather Conditions................52
4.5 TMDL and Allocation For All Weather Conditions..............................................53
4.6 TMDL and Allocation For Dry Weather Conditions.............................................57
5.0 Summary and Future Considerations....................................................................62
6.0 References.................................................................................................................65
Appendix 1 Instream Fecal Coliform Monitoring Data...................................................68
Appendix 2 Dry Weather Dates.......................................................................................75
Appendix 3 Cone Mills WWTP Effluent Data................................................................77
Appendix 4 Mecklenburg County Dry Weather Flow Study Data..................................85
Appendix 5 Mecklenburg County Ground Water Study Data.........................................86
Appendix 6 Sewer System Overflows.............................................................................88
Appendix 7 Calibrated Water Quality Model Parameters.............................................102
Appendix 8 Calibrated Model Hydraulic Parameters....................................................104
Appendix 9 Greensboro’s Municipal NPDES Stormwater Permit................................105
Appendix 10 Public Notification of North Buffalo Creek Fecal Coliform TMDL........107

Final Report North Buffalo Creek Fecal Coliform TMDL Table of Contents
vi

LIST OF TABLES

Table 1.3.1 Drainage area (DA) summary for the TMDL subwatersheds 5
Table 1.4.1 Summary of 2000 population in the upper North Buffalo Creek
watershed 5
Table 1.5.1 Land use/land cover categories used for TMDL modeling 6
Table 1.5.2 Summary of 2000 land use/land cover area 7
Table 1.5.3 Percent coverage of each land use/land cover type 7
Table 1.7.1 Average impervious surface coverage for each LULC type 10
Table 1.7.2 Average impervious surface coverage in each subwatershed 10
Table 1.8.1 Monitoring stations within the TMDL subwatersheds 11
Table 1.9.1 Summary of ambient (dry weather) fecal coliform data collected by
Greensboro’s Stormwater Management Division 13
Table 1.9.2 Summary of storm fecal coliform data collected by Greensboro’s
Stormwater Management Division at the Aycock Street station 13
Table 1.9.3 Summary of ambient (dry weather) fecal coliform data collected by the
Piedmont Triad Council of Governments 14
Table 1.9.4 Summary of instream fecal coliform data collected at Summit Avenue
by Cone Mills WWTP 14
Table 2.1.2.1 Summary of selected stormwater infrastructure features within the
TMDL subwatersheds 18
Table 2.1.2.2 Summary of the number of stormwater structures, pipes, and outfalls
possibly containing non-stormwater flows 19
Table 2.1.2.3 Fecal coliform loading estimates from illicit discharges (non-stormwater
flows) from the stormwater conveyance system 21
Table 2.2.1.1 Estimated dog and cat population in the upper North Buffalo Creek
watershed based on AVMA statistics 22
Table 2.2.1.2 Fecal coliform accumulation rates from pet waste 22
Table 2.2.3.1 Summary of SSOs within the TMDL subwatersheds during the model
simulation period August 1998 through August 2001 25
Table 2.2.4.1 Septic systems within the TMDL subwatersheds 26
Table 2.2.4.2 Estimated fecal coliform load from failing septic systems located within
the upper North Buffalo Creek watershed 27
Table 2.2.5.1 Locations investigated for evidence of waterfowl populations in the
upper North Buffalo Creek watershed 28
Final Report North Buffalo Creek Fecal Coliform TMDL Table of Contents
vii
Table 2.2.5.2 Estimated waterfowl populations for three locations identified within the
TMDL subwatersheds as likely supporting year-round populations 30
Table 2.2.5.3 Estimated fecal coliform loads from waterfowl populations at Lake
Hamilton 31
Table 2.2.5.4 Estimated fecal coliform loads from waterfowl populations at the Bog
Garden 31
Table 2.2.5.5 Estimated fecal coliform loads from waterfowl populations at Buffalo
Lake 31
Table 3.4.1 Model calibration and confirmation periods 39
Table 3.4.1.1 Hydrologic calibration statistics for reach 4 at the Church Street USGS
gage 40
Table 3.4.2.1 Predicted geometric means over four flow regimes 45
Table 4.0.1 Partition of loads between the WLA and LA categories for each source 47
Table 4.5.1 Predicted load reductions necessary for each source to meet the all
weather conditions water quality target during the critical period
(11/9/98 – 12/8/98) 54
Table 4.5.2 Percent load reductions necessary to meet TMDL requirements
associated with the all weather conditions water quality target 56
Table 4.5.3 TMDL components to meet the all weather conditions water quality
target 57
Table 4.6.1 Predicted loads from each source during the dry weather conditions
water quality target critical period (11/9/98 – 12/8/98) 60
Table 4.6.2 Percent load reductions necessary to meet TMDL requirements
associated with the dry weather conditions water quality target 60
Table 4.6.3 TMDL components to meet the dry weather conditions water quality
target 61

LIST OF FIGURES

Figure 1.2.1 North Buffalo Creek watershed in the Cape Fear River Basin 3
Figure 1.3.1 Upper North Buffalo Creek watershed and modeled subwatersheds 4
Figure 1.5.1 Land use/land cover within the TMDL subwatersheds (2000) 8
Figure 1.6.1 Age of residential development in the upper North Buffalo Creek
watershed 9
Figure 1.8.1 Monitoring stations within the TMDL subwatersheds 12
Final Report North Buffalo Creek Fecal Coliform TMDL Table of Contents
viii
Figure 1.9.1 Observed fecal coliform concentrations at Summit Avenue distributed
by predicted stream flow 15
Figure 2.1.2.1 Stormwater structures and pipes, along with corresponding stream
outfalls, suspected of containing non-stormwater flows 20
Figure 2.2.3.1 Distribution of SSOs within the TMDL subwatersheds during the period
August 1998 through August 2001 25
Figure 2.2.4.1 Distribution of septic systems within the TMDL subwatersheds 27
Figure 2.2.5.1 Lakes and ponds in the upper North Buffalo Creek watershed identified
as likely supporting significant year-round waterfowl populations 29
Figure 3.4.1.1 Observed versus predicted flows at Church Street (Reach 4) 41
Figure 3.4.1.2 Frequency distribution of observed and predicted stream flows at Church
Street during the calibration period (8/1/98 – 8/1/00) 41
Figure 3.4.1.3 Observed versus predicted flows at Westover Terrace (Reach 3) 42
Figure 3.4.1.4 Frequency distribution of observed and predicted flows at Westover
Terrace (Reach 3) during the calibration period 42
Figure 3.4.2.1 Observed and predicted fecal coliform loads at Summit Avenue during
the calibration period (August 1998 – August 2000) 44
Figure 4.4.1.1 Predicted fecal coliform concentrations at Summit Avenue under
existing conditions (arithmetic scale) 50
Figure 4.4.1.2 Predicted fecal coliform concentrations at Summit Avenue under
existing conditions (log base 10 scale) 51
Figure 4.4.1.3 Predicted rolling 30-day geometric mean fecal coliform concentration at
Summit Avenue under existing conditions 51
Figure 4.4.1.4 Predicted rolling 30-day geometric mean fecal coliform concentration at
Summit Avenue under existing dry weather conditions 52
Figure 4.5.1 Percentage of delivered load to Summit Avenue from each source
category over the full simulation period 53
Figure 4.5.2 Predicted geometric mean fecal coliform concentration at Summit
Avenue before and after load reductions were applied to the calibrated
model 54
Figure 4.6.1 Percentage of delivered load to Summit Avenue from each source
category during dry weather conditions occurring over the full model
simulation period 57
Figure 4.6.2 Predicted dry weather geometric mean fecal coliform concentration at
Summit Avenue before and after load reductions were applied to the
calibrated model 59

Final Report North Buffalo Creek Fecal Coliform TMDL Acronyms and Abbreviations
ix

ACRONYMS AND ABBREVIATIONS

BIMS NC Basinwide Information Management System
BMP Best Management Practices
CFS Cubic Feet per Second
CFU Colony Forming Units
DA Drainage Area
DEM Digital Elevation Model
DMR Discharge Monitoring Report
DENR NC Department of Environment and Natural Resources
DWM Dynamic Watershed Management System – City of Greensboro
DWQ NC Division of Water Quality
EPA US Environmental Protection Agency
FC Fecal Coliform
GIS Geographic Information System
GPS Global Positioning System
GSO City of Greensboro
I&I Infiltration and Inflow
IR Infrared
LA Load Allocation
LULC Land use/land cover
MF Membrane Filter
MGD Million Gallons per Day
mL Milliliter
MOS Margin of Safety
MPN Most Probable Number
MS4 Municipal Separate Storm Sewer System
NPDES National Pollutant Discharge Elimination System
NRCS Natural Resources Conservation Service
PTCOG Piedmont Triad Council of Governments
WRF Water Reclamation Facility
SMD City of Greensboro Stormwater Management Division
TMDL Total Maximum Daily Load
USGS United States Geological Survey
WinHSPF Windows version of Hydrological Simulation Program - FORTRAN
WLA Waste Load Allocation
WQS Water Quality Standard
WWTP Wastewater Treatment Plant
Final Report North Buffalo Creek Fecal Coliform TMDL Executive Summary
x

EXECUTIVE SUMMARY

The City of Greensboro’s Department of Water Resources, in partnership with the NC
Division of Water Quality (DWQ) and local stakeholders, have developed a fecal
coliform Total Maximum Daily Load (TMDL) for the upper North Buffalo Creek
watershed. A TMDL is an estimate of the
maximum amount of pollutant load, e.g.
fecal coliform, which a waterbody can
receive and still maintain water quality
standards.

The TMDL is designed to provide an
objective analysis of potential sources of
bacteriological contamination within the
watershed, as well as the predicted impact
these sources have on water quality under
a variety of weather and stream flow
conditions. This information is intended to
enhance the City’s ongoing efforts to
improve instream water quality and
provide a foundation for future
management initiatives.







 



Approximately 8.7 stream miles of the upper North Buffalo Creek mainstem have been
listed as impaired in NC’s 2002 303(d) List due to elevated fecal coliform concentrations
(DWQ, 2003). The stream’s impaired status is a reflection that water quality standards
for fecal coliform are not being met. This in turn is an indication that recreational users
of the water resource may be at an elevated risk of contracting water borne diseases from
human pathogens. The overall management goal is to reduce instream fecal coliform
concentrations to a level such that recreational users can safely enjoy clean streams
throughout the watershed.

To achieve this goal the TMDL defines two water quality targets: one target for dry
weather when recreational use is at its highest; and another target for all weather
conditions reflective of both wet and dry periods. Defining two TMDL targets is
advantageous for several reasons. First, the dry weather target provides a framework for
local watershed managers to focus their limited resources towards reducing pollutant
loadings during a period when user exposure to potential pathogens is likely at its
highest. Thereby, managers can optimize the use of their resources while also pursuing a
target recognized by the DWQ and the US Environmental Protection Agency (EPA).
Second, the all weather conditions target supports a traditional TMDL framework for
Children enjoying a cool stream on a warm day. This tributary to North Buffalo Creek runs through Fisher
Park, and is frequently used for recreation, especially
in the summer. The TMDL summarized herein is
designed to support management efforts to reduce instream human pathogens such that recreational uses
will be protected, and where necessary restored.
Final Report North Buffalo Creek Fecal Coliform TMDL Executive Summary
xi
achieving fecal coliform water quality standards under the most critical weather and
stream flow conditions identified within the analysis period (August 1998 – August
2001). This target reflects a longer term goal for achieving standards when the number of
potential contributing sources are at its highest. Thus, the TMDL summarized herein is
actually two TMDLs reflecting different rainfall runoff conditions.

For both TMDLs the target instream fecal coliform concentration is a geometric mean
concentration of < 200 cfu/100mL. Beginning on p. 47 is additional information about
the water quality targets. North Buffalo Creek at Summit Avenue is the point within the
watershed at which these targets will be applied.










Upstream of Summit Avenue - the TMDL compliance point - the watershed has a
drainage area of 21.8 mi2. This area subject to the TMDL includes a portion of
Greensboro’s downtown and is generally “built-out” from a development perspective.
Residential land uses dominate and cover approximately 38% of the TMDL area, with
roads (right-of-ways) covering approximately 15%. Forests cover approximately 20% of
the TMDL area.

Based on an analysis of 2000 US Census data, approximately 59,000 people reside within
the TMDL area, which translates into an average population density of 4.2 persons per
acre. This compares to a city-wide population density of approximately 3.0 persons per
acre. The average impervious coverage across the TMDL area is 26%, which is a level
high enough to result in significant measurable impacts to water quality (Schueler, 1994).











Nine water quality monitoring stations, sampled by various organizations, are located
within the TMDL area. Monitoring data indicate that fecal coliform concentrations in
streams reaches throughout the watershed are high by most measures. Based on data
collected at these monitoring stations the following generalizations can be made about the
observed bacteriological conditions in the upper North Buffalo Creek watershed:

···· With only a few exceptions, the geometric means of the various datasets are
consistently above 200 cfu/100mL - suggesting bacteriological contamination of the
creek is occurring under a variety of runoff and seasonal conditions (200 cfu/100mL
is the threshold fecal coliform concentration referenced in NC’s water quality
standard).
···· The geometric mean of the various ambient (dry weather) datasets are also
consistently above 200 cfu/100mL – suggesting non-stormwater driven sources are
important contributors.
···· Fecal coliform concentrations tend to be higher in the summer than at other times of
the year, which is consistent with other general findings reported in the literature
Final Report North Buffalo Creek Fecal Coliform TMDL Executive Summary
xii
(CWP, 1999). This is significant as recreational use of the waters tends to be highest
during the warm summer months.
···· Fecal coliform concentrations during storm periods are consistently higher than
during ambient conditions – suggesting nonpoint sources of bacteria are also
important contributors.









A detailed assessment of potential sources of fecal coliform loads within the watershed
was performed as part of the TMDL development process. With stakeholder input, an
effort was made to explicitly identify as many source types as was practical. While this
approach is more costly in terms of time and effort, in the long run a detailed assessment
will better support future implementation decisions. The following is a list of sources
included in the TMDL:

···· Cone Mills WWTP – permitted to discharge 1.25 MGD of treated
industrial/domestic wastewater (facility no longer directly discharging to North
Buffalo Creek).
···· Exfiltrating sanitary sewers – loads from this source were simulated as a constant
fecal coliform concentration in groundwater based on limited studies conducted in
Mecklenburg County for a TMDL approved by EPA in 2002.
···· Failing septic systems - 56 addresses within the TMDL area were identified as
possibly using on-site wastewater treatment. Based on the collective experience of
the TMDL stakeholders an estimated failure rate of 15% was applied for calculating
loads from this source.
···· Illicit discharges from the stormwater conveyance system – 66 illicit discharges
were simulated in the TMDL based on field mapping data.
···· Pets – 13,700 dogs and 15,300 cats are estimated to reside within the TMDL area.
···· Sewer System Overflows (SSOs) – 131 SSOs were accounted for in the TMDL
based on data maintained by the City of Greensboro.
···· Waterfowl – loads from waterfowl populations in Lake Hamilton, the Bog Garden,
and Buffalo Lake were included in the TMDL.
···· Other sources – source category designated to account for sources not explicitly
identifiable/quantifiable within the watershed, e.g. urban wildlife populations. Loads
from these sources were quantified using model calibration procedures, and were
assumed to be delivered to the stream via stormwater runoff.




!

" 

Water quality computer models are frequently used during TMDL development for
establishing a relationship between instream water quality conditions and the contributing
watershed. These models use mathematical equations to represent the important physical
and chemical processes which affect the environment.
Final Report North Buffalo Creek Fecal Coliform TMDL Executive Summary
xiii

Hydrologic Simulation Program – Fortran (WinHSPF version 2.0.6) was chosen as the
modeling platform for development of this TMDL. WinHSPF is a public domain
watershed model maintained and distributed by the US EPA. WinHSPF is a continuous
simulation, precipitation-driven model designed to calculate point and nonpoint source
pollutant loadings, downstream transport, and instream pollutant decay. A model
simulation period of 8/1/98 – 8/1/01 was chosen in order to take advantage of local
precipitation and water quality data collected within the TMDL area for model
calibration.





#






The calibrated WinHSPF model was used to assess the load contributions from the
various sources delivered to the TMDL compliance point – Summit Avenue. The pie
charts below illustrate the relative contributions under all weather conditions and dry
weather conditions, respectively.

Percentage of delivered load to Summit Avenue from each source category over the full
simulation period (all weather conditions):

* When interpreting this pie chart it is important to keep in mind that Other Sources represent the load
which could not reasonably be accounted for in the source assessment using the best available data. The Other Sources category could include, for instance, loads from unknown wildlife
populations. However, contributions from Other Sources could also reflect an underestimation of
the loads from one or more of the identified sources.

















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Final Report North Buffalo Creek Fecal Coliform TMDL Executive Summary
xiv
Percentage of delivered load to Summit Avenue from each source category under dry
weather conditions:

Note from the first pie chart that during the full simulation period (reflective of all
weather conditions) stormwater related sources contribute the vast majority of the
delivered load to Summit Avenue. During dry weather conditions, human sources of
fecal coliform tend to comprise the majority of the delivered load.


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A TMDL is the calculation of the maximum amount of pollutant loading that a receiving
waterbody can assimilate while still achieving water quality targets. Per federal rules
TMDLs must include a margin of safety which accounts for uncertainty in the analysis.
As a means of meeting this requirement the water quality targets for both dry weather and
all weather conditions were lowered from 200 cfu/100mL to 180 cfu/100mL.

To calculate the TMDL, load reductions were taken from the calibrated model until all of
the 30 day geometric means were below the target threshold of 180 cfu/100mL, which
includes the explicit margin of safety. In addition, the model output was assessed to
ensure that no more than 6 (20%) of the daily fecal coliform predictions were greater than
400 cfu/100mL, in accordance with the all conditions water quality target. The figure
below illustrates the predicted rolling 30 day geometric mean fecal coliform
concentration at Summit Avenue after load reductions were applied to the calibrated
model.




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Final Report North Buffalo Creek Fecal Coliform TMDL Executive Summary
xv
Predicted 30 day geometric mean fecal coliform concentration at Summit Avenue under all
weather conditions. Geometric means for both existing conditions and under TMDL load
reductions are shown:

The following figure illustrates predicted geometric mean fecal coliform concentrations
under dry weather conditions.

Predicted “30 day” geometric mean fecal coliform concentration at Summit Avenue under
dry weather conditions. Geometric means for both existing conditions and under dry
weather TMDL load reductions are shown:
10
100
1000
10000
Aug-98 Nov-98 Feb-99 May-99 Aug-99 Nov-99 Feb-00 May-00 Aug-00 Nov-00 Feb-01 May-01
Target 180/100mL
Existing Conditions
TMDL Allocation
FC Conc. #/100mL –
30 day geometric mean
Simulation Period
10
100
1000
Aug-98 Nov-98 Feb-99 May-99 Aug-99 Nov-99 Feb-00 May-00 Aug-00 Nov-00 Feb-01 May-01 Aug-01
Target
TMDL Allocation
Existing Conditions
FC Conc. #/100mL –
30 day geometric mean
Simulation Period
Final Report North Buffalo Creek Fecal Coliform TMDL Executive Summary
xvi

The final stages of developing a TMDL involve making decisions about which sources
should be reduced and by how much. In large measure these decisions are based on
which sources are the major contributors, as well as which sources are controllable from
a practical standpoint. To facilitate an adaptive management approach, as well as to
logically partition the responsibility of implementation among management
organizations, TMDLs typically group sources into allocation categories. These
categories represent groups of sources which fall under common permitting or
management frameworks.

The following two tables outline the allocation categories and the percent load reductions
necessary to meet the TMDL requirements associated with the all weather conditions and
dry weather conditions water quality targets. The distribution of individual sources
among the categories are described in the footnotes, with additional detail presented in
Part 4 of this report.

Percent load reductions necessary to meet TMDL requirements associated with the all
weather conditions water quality target.

TMDL Allocation Category TMDL % Reduction
MS4 1 96%
Nonpoint Sources 2 93%
Cone Mills WWTP 3 N/A
1 MS4 = Municipal Separate Storm Sewer System. This allocation category includes that portion of the load from pets, Other Sources, and the full load from illicit discharges, which are transported to the receiving stream via the NPDES permitted municipal stormwater conveyance system. 2 The nonpoint source TMDL allocation category includes that portion of the load from pets, Other Sources, and
the full loads from exfiltrating sanitary sewers, SSOs, failing septic systems, and waterfowl which are
transported to the receiving stream by means other than the MS4.
3 Since the Cone Mills WWTP is no longer discharging, a load reduction is not applicable for the purposes of this TMDL.

Percent load reductions necessary to meet TMDL requirements associated with the dry
weather conditions water quality target.

TMDL Allocation Category TMDL % Reduction
MS4 72%
Nonpoint Sources 70%
Cone Mills WWTP N/A

Final Report North Buffalo Creek Fecal Coliform TMDL 1.0 Introduction
1

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The North Carolina Division of Water Quality (DWQ) has identified an 8.7 mile segment
of North Buffalo Creek as impaired due to elevated fecal coliform concentrations (DWQ,
2003). The impaired segment extends from the stream’s source to just above the North
Buffalo wastewater treatment plant (WWTP) near Summit Avenue. Fecal coliform
bacteria is a commonly used indicator test organism for detecting the possible presence of
human pathogens in lakes, streams, and estuaries throughout NC.

DWQ has classified North Buffalo Creek as Class C waters (DWQ, 1985). In NC, waters
with a primary classification of Class C are to be managed for the protection of secondary
recreational uses such as swimming, wading, boating, and other uses involving human
body contact with water where such activities take place in an infrequent, unorganized, or
incidental basis (DENR, 2003). The elevated levels of fecal coliform found in North
Buffalo Creek during both wet and dry weather conditions suggest there may be an
increased health risk to recreational and other users of the water resource from bodily
contact with the stream.

Section 303(d) of the Clean Water Act
(CWA) requires states to develop a list
of waters not meeting water quality
standards or which have impaired uses.
This list, contained within Categories 4
through 7 of the Integrated Report, is
submitted biennially to the US
Environmental Protection Agency
(EPA) for review. The 303(d) process
requires that a Total Maximum Daily
Load (TMDL) be developed for each of
the waters appearing on Category 5 of
the Integrated Report. The objective of
a TMDL is to estimate the maximum
amount of a pollutant (e.g. fecal
coliform) that a waterbody can receive
and still meet water quality standards,
and to allocate that load among point
and nonpoint sources (USEPA, 1991).

The City of Greensboro’s Department of Water Resources has partnered with DWQ and
interested local stakeholders to develop a TMDL for fecal coliform for the impaired
segment of North Buffalo Creek. The TMDL is intended to serve as an important
North Buffalo Creek
South Buffalo Creek
1 0 1 2 Miles
Reach impaired for fecal
coliform highlighted in red
North Buffalo Creek watershed. Approximately 8.7 miles of the upper North Buffalo Creek mainstream are listed in NC’s
303(d) List due to elevated fecal coliform concentrations.
Summit Avenue has been chosen as the TMDL compliance
point.
Summit Ave.
Final Report North Buffalo Creek Fecal Coliform TMDL 1.0 Introduction
2
management tool for guiding local implementation strategies designed to reduce loadings
of potential human pathogens to the stream. Generally, the primary components of a
TMDL, as identified by EPA (1991, 2000a) and the Federal Advisory Committee are as
follows:

Target Identification or selection of pollutant(s) and endpoint(s) for consideration. An
endpoint is an instream numeric target. The pollutant and endpoint are generally
associated with measurable water quality related characteristics that indicate
compliance with water quality
standards. North Carolina indicates
known problem pollutants on the
303(d) List.

Source assessment. Sources that
contribute to the impairment
should be identified and loads
quantified, to the extent that that is
possible.

Reduction target. Estimation of the level
of pollutant reduction needed to
achieve the water quality goal.
The level of pollution should be
characterized for the waterbody, highlighting how current conditions deviate from
the target endpoint. Generally, this component is identified through water quality
modeling.

Margin of safety. The margin of safety addresses uncertainties associated with pollutant
loads, modeling techniques, and data collection. Per EPA (2000a), the margin of
safety may be expressed explicitly as unallocated assimilative capacity (portion of
TMDL) or implicitly through conservative assumptions. The margin of safety
should be included in the reduction target.

Allocation of pollutant loads. Allocating available pollutant load (TMDL), and hence
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. The load allocation portion of the TMDL accounts for
the loads associated with existing and future nonpoint sources. Any future
nonpoint source loading should remain within the TMDL that is calculated in this
assessment; in other words, this TMDL does not leave allocation for future
sources.

Seasonal variation. The TMDL should consider seasonal variation in the pollutant loads
and endpoint. Variability can arise due to stream flows, temperatures, and
exceptional events (e.g., droughts and hurricanes).

North Buffalo Creek at Summit Avenue.
Final Report North Buffalo Creek Fecal Coliform TMDL 1.0 Introduction
3
Critical conditions. Critical conditions occur when fecal coliform levels exceed the
standard by the largest amount. If the modeled load reduction is able to meet the
standard during critical conditions, then it should meet the standard at all, or
nearly all, times.

The North Buffalo Creek TMDL establishes two instream water quality targets and
defines a watershed “compliance point” along the mainstem at Summit Avenue. The
targets are designed to be consistent with the State’s water quality standard for fecal
coliform and provide general guidance for a future implementation plan. Section 303(d)
of the CWA and the Water Quality Planning and Management regulation (USEPA,
2000a) require EPA to review all TMDLs for approval or disapproval. Once EPA
approves the TMDL, then North Buffalo Creek may be moved to Category 4a of the 2002
Integrated Report. North Buffalo Creek will remain on Category 4a until compliance
with water quality standards is achieved. Note that the entire length of North Buffalo
Creek, from its source to the confluence with South Buffalo Creek, is also listed in the
Integrated Report as being biologically impaired. This TMDL does not explicitly address
this issue as the causal agents of the biological impairment have not yet been identified.

%&-  ).$
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The North Buffalo Creek watershed is located in the headwaters of the Cape Fear River
Basin in Guilford County (Figure 1.2.1). North Buffalo Creek, just above its confluence
with South Buffalo Creek, has a drainage area of approximately 44 mi2. Drainage from
the North Buffalo Creek watershed generally flows in an easterly direction and ultimately
feeds the Haw River above Jordan Lake.
N
20 0 20 40 Miles
North Buffalo Creek Watershed
Cape Fear
River Basin
Figure 1.2.1 North Buffalo Creek watershed in the Cape Fear River Basin.
Haw River
Jordan Lake
Deep River
Cape Fear River
Final Report North Buffalo Creek Fecal Coliform TMDL 1.0 Introduction
4


%&/ + ).$

This TMDL addresses fecal coliform impairment in the upper half of the North Buffalo
Creek watershed as outlined in NC’s 2002 303(d) List. For management and modeling
purposes the upper watershed was delineated into nine subwatersheds (Figure 1.3.1).
Delineation of these subwatersheds was based on hydrologic considerations, land
use/land cover patterns, and the locations of stream flow and water quality monitoring
stations for model calibration/confirmation. The upper watershed defined for this
TMDL, which has a drainage area of 21.8 mi2, is wholly within the city limits of
Greensboro. Table 1.3.1 summarizes total contributing and individual drainage areas for
each subwatershed.

1
2
3
4
5
6.1
6.2
7
8
Summit Ave.
Subwatershed ID number 1
Buffalo Lake
Figure 1.3.1 Upper North Buffalo Creek watershed and modeled subwatersheds.
Final Report North Buffalo Creek Fecal Coliform TMDL 1.0 Introduction
5

Table 1.3.1 Drainage area (DA) summary for the TMDL subwatersheds.

1 Example: the cumulative drainage area to the outlet of subwatershed 3 equals the drainage areas of subwatersheds 1, 2, and 3 (5.1+4.0+0.5=9.6).
2 Subwatershed 6 drains to the largest open waterbody in the watershed – Buffalo Lake. The upper
subwatershed (6.1) drains to the head of the lake and subwatershed 6.2 drains directly into the lake.

%&0 "*"+# *,
! 

Approximately 26% of Greensboro’s total population (223,891 as per 2000 US census)
lives in the upper North Buffalo Creek watershed. Population density in the upper
watershed averages 4.2 persons/ac. Subwatersheds 3 and 4 have the densest populations
as well as some of the oldest residential developments. Table 1.4.1 summarizes the 2000
population by subwatershed based on US census block data.

Table 1.4.1 Summary of 2000 population in the upper North Buffalo Creek watershed.
Subwatershed 2000 Population Estimate 2000 Density (persons/ac)
1 13,123 4.0
2 8,886 3.5
3 1,532 4.6
4 16,117 5.3
5 3,058 3.4
6.1 3,515 4.2
6.2 6,439 4.1
7 6,353 4.3
8 0 0.0
Total = 59,023 Average density = 4.2

Subwatershed Subwatershed DA
(sq. mi)
Total Contributing DA to
the Subwatershed Outlet
(sq. mi) 1
1 5.1 5.1
2 4.0 4.0
3 0.5 9.6
4 4.7 14.3
5 1.4 15.7
6.1 2 1.3 1.3
6.2 2 2.5 3.8
7 2.3 6.1
8 0.05 21.8
Final Report North Buffalo Creek Fecal Coliform TMDL 1.0 Introduction
6
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In 2002 the City of Greensboro completed a city-wide GIS land use/land cover (LULC)
characterization project. A hybrid land use/land cover classification system comprised of
33 categories was devised to specifically support a variety of water resources
management and planning initiatives. The LULC GIS database was built from 2000
orthophotography, parcel and zoning data, as well as numerous additional planimetric
data sources. For modeling and reporting purposes the LULC categories were condensed
into 9 broader categories. Table 1.5.1 summarizes the LULC categories used to support
the TMDL.

Table 1.5.1 Land use/land cover categories used for TMDL modeling.
LUCL Category Description
Dwntwn Downtown area - Includes a specific densely developed, multi-use
area near the center of the city.
HERB Managed herbaceous – Cemeteries, lawns (>1 ac), open parks, golf
courses, and athletic fields.
ICO
Industrial/Commercial/Office – includes low, medium, and high
density industrial, commercial, and office properties greater than 1
acre.
INST Institutional – includes schools, university/colleges, churches, and
government uses.
MF Multi-family residential – includes apartments, condominiums, and
townhomes.
RES Single family residential – includes all single family detached homes.
Also includes duplexes.
ROW Right-of-way – includes all roadways and adjacent right-of-way on
either side of the road.
WATER Open waterbodies – includes lakes and ponds with a surface area
greater than 1 acre.
WOODS
Wooded and natural areas – includes areas greater than 1 acre
where tree cover predominates (>75%). Also includes 1 acre or
greater areas with a mix of trees and grass/herbaceous
vegetation/low-growing brush.

Table 1.5.2 and 1.5.3 summarizes the area and percent coverage of each LULC type,
respectively. On average the upper North Buffalo Creek watershed is dominated by
single family residential land uses as illustrated in the Figure 1.5.1. Roadways and
industrial/commercial/office properties are the second and third most prominent
developed land uses, respectively. On average, wooded areas cover slightly less than
20% of the upper watershed.

Final Report North Buffalo Creek Fecal Coliform TMDL 1.0 Introduction
7
Table 1.5.2 Summary of 2000 land use/land cover area. Values rounded to the nearest
acre. Area in square miles presented in parenthesis.

Subwater-shed Dwntwn HERB ICO INST MF RES ROW WATER WOODS Totals
1 0 (0) 228 (0.36) 452 (0.71) 104 (0.16) 155 (0.24) 1,288 (2.01) 497 (0.78) 19 (0.03) 521 (0.81)
3,263
(5.10)
2 0 (0) 29 (0.05) 288 (0.45) 38 (0.06) 6 (0.01) 1,110 (1.73) 438 (0.68) 14 (0.02) 613 (0.96)
2,536
(3.96)
3 0 (0) 23 (0.04) 1 (0.00) 7 (0.01) 16 (0.03) 146 (0.23) 57 (0.09) 2 (0.00) 80 (0.13) 331 (0.52)
4 215 (0.34) 205 (0.32) 445 (0.70) 218 (0.34) 119 (0.19) 967 (1.51) 506 (0.79) 6 (0.01) 338 (0.53) 3,019 (4.72)
5 0 (0) 40 (0.06) 287 (0.45) 25 (0.04) 37 (0.06) 223 (0.35) 139 (0.22) 7 (0.01) 134 (0.21) 892 (1.39)
6.1 0
(0)
10
(0.02)
79
(0.12)
7
(0.01)
35
(0.05)
396
(0.62)
114
(0.18)
0
(0)
191
(0.30)
832
(1.30)
6.2 0
(0)
40
(0.06)
67
(0.10)
42
(0.07)
104
(0.16)
684
(1.07)
209
(0.33)
95
(0.15)
342
(0.53)
1,583
(2.47)
7 0
(0)
93
(0.15)
141
(0.22)
40
(0.06)
108
(0.17)
438
(0.68)
139
(0.22)
5
(0.01)
526
(0.82)
1,490
(2.33)
8 0
(0)
3
(0.00)
3
(0.00)
0
(0)
0
(0)
0
(0)
3
(0.00)
2
(0.00)
26
(0.04)
37
(0.06)
Totals 215
(0.34)
671
(1.05)
1,764
(2.76)
482
(0.75)
578
(0.90)
5,250
(8.20)
2,102
(3.28)
150
(0.23)
2,771
(4.33)
13,984
(21.85)
Subwater- shed Dwntwn HERB ICO INST MF RES ROW WATER WOODS Totals
1 0.0% 7.0% 13.9% 3.2% 4.7% 39.5% 15.2% 0.6% 16.0% 100%
2 0.0% 1.1% 11.4% 1.5% 0.2% 43.8% 17.3% 0.5% 24.2% 100%
3 0.0% 6.8% 0.3% 2.2% 4.9% 44.0% 17.1% 0.6% 24.1% 100%
4 7.1% 6.8% 14.7% 7.2% 3.9% 32.0% 16.8% 0.2% 11.2% 100%
5 0.0% 4.5% 32.2% 2.8% 4.1% 25.0% 15.6% 0.7% 15.1% 100%
6.1 0.0% 1.2% 9.5% 0.9% 4.2% 47.5% 13.7% 0.0% 23.0% 100%
6.2 0.0% 2.5% 4.2% 2.6% 6.6% 43.2% 13.2% 6.0% 21.6% 100%
7 0.0% 6.2% 9.5% 2.7% 7.2% 29.4% 9.4% 0.4% 35.3% 100%
8 0.0% 8.6% 8.3% 0.0% 0.0% 0.0% 8.6% 4.3% 70.3% 100%
Totals 1.5% 4.8% 12.6% 3.4% 4.1% 37.5% 15.0% 1.1% 19.8% 100%
Table 1.5.3 Percent coverage of each land use/land cover type.

Final Report North Buffalo Creek Fecal Coliform TMDL 1.0 Introduction
8
TMDL subwatershed bdry
Legend
DWNTWN
HERB
ICOINSTMFRESROW
WATER
WOODS
0.5 0 0.5 1 1.5 2 Miles
Figure 1.5.1 Land use/land cover within the TMDL subwatersheds (2000).
Final Report North Buffalo Creek Fecal Coliform TMDL 1.0 Introduction
9

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$4#*"!,

Given the predominance of residential land uses in the upper North Buffalo Creek
watershed (average >41% combined single and multi-family), it is useful to examine the
age of these developments as a prelude to the fecal coliform source assessment. The age
of residential development, as determined using parcel records, can provide some insight
into the possible age (and condition) of the stormwater and sanitary sewer infrastructure
systems. Older drainage and sanitary sewer systems, particularly those constructed using
clay pipe, as was common in NC pre-1970s, may be more subject to varying degrees of
deterioration. In particular, deteriorating sanitary sewer lines can be a significant source
of fecal coliform loading to a watershed.

It is important to note however that older residential subdivisions do not necessarily
equate to areas of high fecal coliform loads, particularly where systems have been well
maintained. However, these data do provide useful information for targeting follow-up
investigations to the TMDL. Figure 1.6.1 illustrates the age of residential development in
the upper watershed.

Figure 1.6.1 Age of residential development in the upper North Buffalo Creek watershed.
Only residential areas within the Greensboro city limits are shown.

1920 − 1940
1960 − 1970 1950
1960 − 1970 1950
1920 − 1950
1960 − 1970
1950 − 1960
1910 − 1920
1920 − 1950
1930 − 1950
1960 − 1970
1950 − 1960
WHITE ST
US 29 HY S MCKNIGHT MILL RD
W WENDOVER AVE
W MARKET ST
BENJAMIN PKWY
WENDOVER AVE
North Buffalo Creek Watershed
Age of Residential Areas
Year Built
1850− 1929
1930 − 1959
1960 − 1979
1980 − 1999
Sources: City of Greensboro Parcel GIS Data and EarthData 2002 Landuse Coverages
Final Report North Buffalo Creek Fecal Coliform TMDL 1.0 Introduction
10
%&6 !")4*+
+) 

Impervious surfaces, such as rooftops and parking lots, prevent rainfall from infiltrating
into the ground. The result is an increase in runoff volumes, instream peak flows, and
pollutant loads delivered to a receiving stream. Given the importance of impervious
surfaces in the field of water resources management, the City of Greensboro has invested
in the development of a comprehensive city-wide GIS database of impervious surfaces.
This GIS database includes polygon representations of road surfaces, railroad beds,
parking lots, driveways, rooftops (including residential out buildings), swimming pools,
storage tanks, along with other impervious feature types.

Table 1.7.1 summarizes the results of a GIS analysis undertaken to estimate the average
impervious surface coverage for each LULC type used in this TMDL. Table 1.7.2
outlines the percentage of impervious cover in each subwatershed.

Table 1.7.1 Average impervious surface coverage for each LULC type.

LULC Average %
Impervious Cover
DWNTWN 66%
HERB 0%
ICO 57%
INST 43%
MF 36%
RES 15%
ROW 63%
WATER 0%
WOODS 0%

Table 1.7.2 Average impervious surface coverage in each subwatershed.
Subwatershed % Impervious
Cover
1 26%
2 25%
3 20%
4 33%
5 35%
6.1 23%
6.2 21%
7 19%
8 10%
TMDL area
average 26%

Final Report North Buffalo Creek Fecal Coliform TMDL 1.0 Introduction
11
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 *,

Within the TMDL subwatersheds there are ten fecal coliform monitoring stations and two
USGS stream flow and precipitation gaging stations. The City of Greensboro’s
Stormwater Management Division has four ambient (dry weather) stations at which fecal
coliform samples are collected. Other physical/chemical water quality parameters are
also monitored at these stations. The Aycock Street station also serves as a storm
monitoring station for fecal coliform and other water quality parameters.

In 2001 the Piedmont Triad Council of Governments initiated a special study which
included five sampling stations within the TMDL subwatersheds, in addition to stations
in other watersheds within the Triad region of NC (PTCOG, 2003). A central objective
of the study is to examine instream fecal coliform concentrations during dry weather
conditions.

The USGS, with financial support from the Greensboro Department of Water Resources,
operates two stream flow and precipitation gaging stations within the TMDL
subwatersheds. The Westover Terrace station (02095181) on North Buffalo Creek began
recording daily stream flow in June 1999. The Church Street station (02095271), also on
North Buffalo Creek, began recording in August 1998. Table 1.8.1 and Figure 1.8.1
provide additional information on the monitoring stations located within the TMDL
subwatersheds.

Table 1.8.1 Monitoring stations within the TMDL subwatersheds.
Map
ID
Subwater-
shed Location Stream Agency 1 Ambient 2 Storm 3 Flow 4 PPT 5
A 1 Market St. N. Buffalo PTCOG

B 1 Arboretum/
Lindley Park N. Buffalo SMD

C Head of 3 Elam St. N. Buffalo PTCOG

D Outlet of 3 Aycock/Westover Terrace N. Buffalo USGS


E Outlet of 3 Aycock/Westover Terrace N. Buffalo SMD


F 4 Garland Ave. N. Buffalo PTCOG

G 4 Cridland Ave. N. Buffalo PTCOG

H Outlet of 4 Church St. N. Buffalo USGS


I Outlet of 4 Church St. N. Buffalo SMD

J Outlet of 4 Church St. N. Buffalo PTCOG

K 7 16th St. UT to
N. Buffalo SMD

L Outlet of 8 Summit Ave. N. Buffalo Cone Mills
WWTP


1 PTCOG = Piedmont Triad Council of Governments; SMD = City of Greensboro Stormwater Management Division; USGS = US Geological Survey; Cone Mills WWTP = instream sampling station downstream of discharge.
2 Ambient (dry weather) sampling refers to instream water quality data collected 72 or more hours after a rainfall event.
3 Storm sampling refers to instream water quality data collected within 72 hours of a rainfall event.
4 Flow = Stream flow 5 PPT = Precipitation (rainfall)
Final Report North Buffalo Creek Fecal Coliform TMDL 1.0 Introduction
12

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 #
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The nine different sampling locations within the TMDL subwatersheds provides a
reasonably good picture of bacteriological water quality – particularly during dry weather
conditions when recreational use of the resource is highest. Generally speaking fecal
coliform concentrations at all of the stations are elevated with geometric means of the
observed datasets tending to be over the 200 cfu/100mL threshold referenced in NC’s
bacteriological water quality standard for Class C waters.

Below is a summary of the instream fecal coliform data collected by the three agencies,
SMD, PTCOG, and Cone Mills WWTP, which sample within the TMDL subwatersheds.
Each agency has appropriate quality control procedures in place and uses a State certified
laboratory to process the samples.













SMD ambient and/or storm water quality station
PTCOG ambient water quality station
USGS flow and precipitation gaging station
Cone Mills WWTP NPDES instream station
Figure 1.8.1 Monitoring stations within the TMDL subwatersheds.
A
B
C E
D
F
G
H J
I
L
K
A Map ID
(See Table 1.8.1)
Final Report North Buffalo Creek Fecal Coliform TMDL 1.0 Introduction
13
Greensboro’s Stormwater Management Division Fecal Coliform Data

SMD samples at 4 locations within the TMDL subwatersheds (see Figure 1.8.1). All
stations are ambient monitoring locations with the exception of the Aycock Street station
from which storm (runoff event) samples are also collected. Table 1.9.1 provides a
summary of fecal coliform data collected at each of the SMD monitoring locations.
Appendix 1 includes a listing of the complete dataset with sampling dates and individual
results.

Table 1.9.1 Summary of ambient (dry weather) fecal coliform data collected by
Greensboro’s Stormwater Management Division. 1
Map
ID 2 Station Geometric Mean Of
Ambient Dataset
Geometric Mean Of Summer Ambient Dataset 3
Geometric Mean Of Non-Summer Ambient Dataset 3
Total Number of
Samples
B Arboretum 1,161 2,626 788 28
E Aycock St. 433 1,124 211 14
I Church St. 306 630 178 14
K 16th St. 309 542 203 14
1 Ambient samples are collected 72 or more hours after the last measurable rainfall event. All stations were sampled during the period 7/22/99 – 9/18/01 with the exception of the Arboretum station which was sampled 7/9/96 – 4/14/99.
Geometric means expressed in units of #/100mL.
2 See Figure 1.8.1 for a map of station locations.
3 Summer dataset is defined as those samples collected during the months of June through October. Non-summer is defined as November through May.

Table 1.9.2 Summary of storm fecal coliform data collected by Greensboro’s Stormwater
Management Division at the Aycock Street station. 1
Station
Geometric Mean Of
Storm
Dataset
Geometric
Mean Of Summer Storm Dataset 2
Geometric Mean Of Non-
summer
Storm
Dataset 2
Geometric
Mean Of Ambient & Storm Dataset
Geometric Mean Of Summer
Ambient &
Storm
Dataset
Geometric
Mean Of
Non-
summer Ambient & Storm
Dataset
Number of
Samples
Aycock St. 4,586 11,303 2,921 1,090 2,427 652 9 storm
14 ambient
1 Storm samples are typically collected during or shortly after (within 24 hours) rainfall events. Geometric means expressed in units of #/100mL. Samples collected during the period 7/22/99 – 9/18/01. 2 Summer dataset is defined as those samples collected during the months of June through October. Non-summer is
defined as November through May

Piedmont Triad Council of Governments Fecal Coliform Data

PTCOG sampled 5 stations along the North Buffalo Creek mainstem within the TMDL
subwatersheds as part of a special study conducted in Greensboro and High Point, NC
(PTCOG, 2003). All samples summarized herein were collected at ambient conditions
during the period 6/11/01 – 10/30/01, with the exception of the Elam Street station which
was sampled during 6/5/01 – 10/30/01. Table 1.9.3 summarizes the PTCOG instream
fecal coliform data. Appendix 1 includes a listing of the complete dataset with sampling
dates and individual results.
Final Report North Buffalo Creek Fecal Coliform TMDL 1.0 Introduction
14

Table 1.9.3 Summary of ambient (dry weather) fecal coliform data collected by the
Piedmont Triad Council of Governments. 1
Map
ID 2 Station Geometric Mean Of Ambient
Dataset
Geometric Mean
Of Ambient
Summer Dataset 3
Geometric Mean
Of Ambient
Non-summer Dataset 3
Total Number of
Samples
A Market St. 683 822 454 16
C Elam St. 409 518 172 14
F Garland Ave. 852 1,006 462 14
G Cridland Ave. 470 610 197 13
J Church St. 309 348 206 13
1 Ambient samples are collected 72 or more hours after the last measurable rainfall event. Geometric means expressed in units of #/100mL. 2 See Figure 1.8.1 for a map of station locations. 3 Summer dataset is defined as those samples collected during the months of June through October. Non-summer is
defined as November through May

Cone Mills WWTP Instream Fecal Coliform Data

As a condition of the Cone Mill NPDES wastewater discharge permit (NC0000876) the
facility is required to conduct instream sampling for fecal coliform and other water
quality parameters at Summit Avenue.† Table 1.9.4 summarizes 300 fecal coliform
samples collected during the period 8/3/1998 – 11/24/2000 as reported in the facility’s
discharge monitoring reports (DMRs). Appendix 1 includes a listing of the complete
dataset with sampling dates and individual results.

Table 1.9.4 Summary of instream fecal coliform data collected at Summit Avenue by Cone
Mills WWTP. 1
Map
ID 2 Station
Geometric Mean Of
Complete
Dataset
Geometric Mean Of
Ambient
Samples 3
Geometric Mean Of
Storm
Samples 3
Geometric Mean Of
Summer
Dataset 4
Geometric
Mean Of
Non-summer Dataset 4
Total
Number Of Samples
L Summit Ave. 429 206 680 619 300 300
1 Geometric means expressed in units of #/100mL.
2 See Figure 1.8.1 for a map of station locations. 3 Cone Mills was not required by permit to parse their sampling into ambient and storm sampling periods. However, for the purposes of this TMDL the complete dataset was segregated into samples collected during dry weather periods
(ambient) and samples collected during or soon after a rainfall event. Precipitation data collected at the USGS gaging
stations at Westover Terrace and Church Street were used to identify dates in which the cumulative daily rainfall total was 0.1” or more. Instream samples collected within 72 hours of these rain event days were classified as storm samples. All others were considered ambient samples. 4 Summer dataset is defined as those samples collected during the months of June through October. Non-summer is
defined as November through May.

† During the TMDL simulation period (August 1998 – August 2001) Cone Mills was permitted to
discharge 1.25 MGD of treated industrial/domestic wastewater into North Buffalo Creek approximately
0.2 miles upstream of Summit Avenue. During the summer of 2001 Cone Mills began diverting its
discharge to the City of Greensboro’s North Buffalo Creek WWTP for treatment and ultimate discharge
below Summit Ave.
Final Report North Buffalo Creek Fecal Coliform TMDL 1.0 Introduction
15
Figure 1.9.1 illustrates the observed fecal coliform concentrations at Summit Avenue
over four stream flow regimes.† The x-axis is analogous to the percent chance of
exceedance for a given flow. For example, data points in line with the 50% flow duration
interval represent fecal coliform concentrations collected during predicted median flow.

Figure 1.9.1 Observed fecal coliform concentrations at Summit Avenue distributed by
predicted stream flow.1
1 High flows: 559 (modeled peak) – 70 cfs; Transition flows: 69 – 22 cfs; Typical flows: 21 - 10 cfs; Low flows: 9 – 3.4 (modeled low) cfs
The following is a summary of findings derived from Figure 1.9.1. The data summary is
not a direct comparison to the NC fecal coliform standard. Rather, it is intended to be a
general characterization of bacteriological water quality over a snap shot in time. The
200/100mL and 400/100mL values presented in the first six bullets are referenced against
grab sample results and not geometric means.

···· 72% of all the samples are above 200/100mL
···· 55% of all the samples are above 400/100mL
···· 62% of samples collected during low flow conditions exceed 200/100mL
···· 72% of samples collected during typical flow conditions exceed 200/100mL
···· 85% of samples collected during transition flow conditions exceed 200/100mL
···· 96% of samples collected during high flow conditions exceed 200/100mL
···· Geometric mean of samples collected during high flows = 1,465/100mL
···· Geometric mean of samples collected during transition flows = 942/100mL
···· Geometric mean of samples collected during typical flows = 479/100mL
···· Geometric mean of samples collected during low flows = 209/100mL

† There is no stream flow gaging station at Summit Avenue. Hence, predicted flows from the model were
used in this analysis.








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Flow Duration Interval (%)















Fecal Coliform
Conc.
(#/100mL)
Final Report North Buffalo Creek Fecal Coliform TMDL 1.0 Introduction
16
···· Over all flow regimes, except high, the range of observed concentrations (highest
and lowest values) is relatively consistent.

Exceedances of the 200/100mL threshold value occur over the full range of flows, but
generally occur at higher percentages as flows increase. Given that elevated fecal
coliform concentrations occur over the full spectrum of flow conditions, both stormwater
and non-stormwater driven sources need to be considered in the TMDL.

General Findings Applicable To Each Sampling Station

Based on a review of the data presented in Tables 1.9.1 through 1.9.4 the following
generalizations can be made about the observed bacteriological conditions in the upper
North Buffalo Creek watershed. Note that these generalizations are not intended to be a
formal evaluation of secondary recreational use support.

···· With only a few exceptions, the geometric means of the various datasets are
consistently above 200 cfu/100mL - suggesting bacteriological contamination of the
creek is occurring under a variety of runoff and seasonal conditions.
···· The geometric mean of the various ambient (dry weather) datasets are also
consistently above 200 cfu/100mL – suggesting non-stormwater driven sources are
important contributors.
···· Fecal coliform concentrations tend to be higher in the summer than at other times of
the year which is consistent with other general findings reported in the literature
(CWP, 1999). This is significant as recreational use of the waters tends to be highest
during the warm summer months.
···· Fecal coliform concentrations during storm periods are consistently higher than
during ambient conditions – suggesting nonpoint sources of bacteria are also
important contributors.

Final Report North Buffalo Creek Fecal Coliform TMDL 2.0 Source Assessment
17

----&'

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One of the key elements of a TMDL analysis is the identification of sources of fecal
coliform throughout a watershed, and the estimate of the amount of pollutant loading
contributed by each sources. Potential sources of fecal coliform are numerous, widely
distributed spatially, and often occur in combination. In addition, different sources
translate into varying degrees of risk to recreational users of the water resource.
However, it is generally recognized that human sources of fecal coliform pose the
greatest health risks (CWP, 1999).

Sources of fecal coliform loads can be assigned to two broad classes: point source loads
and nonpoint source loads. Point sources of fecal coliform are characterized as those
which enter a water body from discrete, often identifiable locations such as pipes.
Nonpoint sources of fecal coliform are diffuse sources often not entering a water body at
discrete, fixed locations. Nonpoint source loads tend to be variable in time and space,
making them particularly challenging to quantify.

Working with the project stakeholders eight fecal coliform source types were identified
as being potentially significant contributors in the upper North Buffalo Creek watershed.
This list includes: Cone Mills WWTP (NC0000876); illicit discharges from the City of
Greensboro’s NPDES Phase I permitted stormwater conveyance system; pets
(specifically dogs and cats); exfiltrating sanitary sewer lines; sewer system overflows
(SSOs); failing septic systems; waterfowl (specifically ducks and geese); and other
sources, presently unidentifiable, with delivery mechanisms assumed to be associated
with rainfall runoff events.

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Cone Mills Corporation had a major
industrial discharge approximately 0.2
stream miles above Summit Avenue during
the TMDL model simulation period. The
facility was permitted to discharge 1.25
MGD of treated effluent with a monthly
geometric mean fecal coliform limit of 200
cfu/100mL. Cone Mills is a textile
manufacture for the apparel and home
furnishings market. The facility is still in
operation, however it no longer directly
discharges to the stream. Rather, its
pretreated wastewater is now sent to the
City of Greensboro’s North Buffalo Creek
North Buffalo Creek
Buffalo Lake
Cone Mills
WWTP
The Cone Mills facility is the only NPDES permitted
WWTP with a limit for fecal coliform within the TMDL
watersheds.
Final Report North Buffalo Creek Fecal Coliform TMDL 2.0 Source Assessment
18
WWTP for final treatment and disposal. The North Buffalo Creek WWTP discharges
downstream of the reach impaired for fecal coliform and is therefore not included in this
TMDL. Daily effluent flow and daily fecal coliform monitoring data submitted to DWQ
by Cone Mills were used to estimate loads from this facility (Kebede, 2003).

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Greensboro’s Stormwater Management
Division (SMD) is the lead local
government agency responsible for
managing the city’s stormwater
conveyance infrastructure. Greensboro is
permitted under EPA’s Phase I
stormwater program. In 2002 SMD
completed a state-of-the-art GIS mapping
project of its stormwater conveyance
system. This project involved locating
stormwater inlets, manholes, pipes, and
culverts using a combination of GPS and
traditional survey technologies. These
data were incorporated into a GIS
framework. Natural streams, man-made
open channels, and lake/ponds were also
included in the GIS database to provide
complete hydrologic conductivity within a watershed. Table 2.1.2.1 summarizes the
number of stormwater inlets and length of drainage pipe (12” or greater) within the
TMDL subwatersheds as identified through the stormwater infrastructure mapping
project.

Table 2.1.2.1 Summary of selected stormwater infrastructure features within the TMDL
subwatersheds.
Subwatershed
Number Of
Stormwater Inlets
(e.g. curb inlet, yard
inlet, etc.)
Total Length Of 12” Or
Greater Diameter Pipe
(miles)
1 2,070 40.1
2 1,781 35.2
3 210 3.0
4 2,693 47.7
5 647 11.9
6.1 457 10.2
6.2 1,012 21.3
7 557 12.7
8 13 0.4
Total 9,440 182.5

Nighttime aerial infrared thermographic image of a possible inappropriate discharge into North Buffalo Creek from an
institutional facility in subwatershed 1. Data from the
infrared flyover became available too late for use in the TMDL source assessment. However, these data will be used to support implementation strategies.
N. Buffalo Ck.
“Warm” discharge shows up brighter on IR image than creek at ambient
temperature.
Final Report North Buffalo Creek Fecal Coliform TMDL 2.0 Source Assessment
19
In addition to the locational mapping, various attributes which describe the conveyance
system were also collected such as inlet type, pipe size, and pipe invert elevation.
Attribution of the conveyance system also included an inventory of any illegal tie-ins to
the system. An illegal tie-in is defined as any unauthorized private piped connection to
the public stormwater conveyance system. The mapping project was not designed to
assess whether or not discharges from illegal tie-ins are comprised solely of stormwater.
These determinations are being made through follow-up investigations over time.

However, the mapping database does include a number of useful attributes which were
used to identify the possible presence of illicit discharges to the stormwater system.
These attributes included whether or not an unusual odor, such as from raw sewage, was
emanating from the system; whether or not flows in the system were unnaturally colored
or cloudy; as well as specific comments recorded in the database by the mapping field
crews which would suggest the presence of an illicit discharge in the system. Using these
attributes an analysis of the stormwater infrastructure database was conducted to identify
the number of structures and pipes possibly containing non-stormwater flows (illicit
discharges). The outfalls from which these non-stormwater flows ultimately discharge
were identified using the system connectivity built within the GIS database. Table
2.1.2.2 summarizes the results of this analysis. Figure 2.1.2.1 illustrates the locations of
stormwater structures and pipes suspected of containing non-stormwater flows.

Table 2.1.2.2 Summary of the number of stormwater structures, pipes, and outfalls
possibly containing non-stormwater flows.
Subwatershed Number of Structures
(e.g. inlets, manholes) Number of Pipes Number of Outfalls to
1:24K Scale Streams 1
1 6 10 9
2 11 12 8
3 0 0 2 2
4 14 5 27 3
5 8 8 6
6.1 2 7 1
6.2 9 8 11
7 1 1 2
8 0 0 0
Total 51 51 66
1 This column represents the number of discreet locations the possible discharge enters a 1:24,000 scale stream. For
example, in subwatershed 1 based on the connectivity of the stormwater conveyance system, the 6 structures and 10
pipes suspected of possibly containing non-stormwater flows ultimately discharge to a stream at 9 unique locations. 2 The stormwater infrastructure database indicated possible evidence that an illicit discharge had occurred at 2 instream locations. The database did not yield any evidence that the discharge was associated with a specific stormwater structure or pipe.
3 Based on the connectivity of the stormwater conveyance system, 14 structures and 5 pipes were identified as possibly
containing non-stormwater flows discharging at 9 unique locations. However, this number of non-stormwater
discharges is suspected of being an underestimate due to uncertainties associated with the mapping database. Approximately 215 acres of Greensboro’s downtown area is within subwatershed 4. The downtown area contains some of the City’s older stormwater infrastructure – much of which was inaccessible during the mapping project. Due
in part to buried manholes, 183 stormwater pipes in the downtown area could not be inspected and their network
connectivity verified. For the purposes of this TMDL, it was assumed that 10% of these older, inaccessible pipes may contain illicit tie-ins (i.e. 183 *10% = 18 pipes). It was also assumed that each of these pipes discharge to a discreet location. Therefore in subwatershed 4 a total of 27 (18+9) outfalls possibly containing non-stormwater flows were
used to estimate fecal coliform loads from illicit discharges.

Final Report North Buffalo Creek Fecal Coliform TMDL 2.0 Source Assessment
20

Figure 2.1.2.1 Stormwater structures and pipes, along with corresponding stream outfalls,
suspected of containing non-stormwater flows.

Flow and fecal coliform concentration measurements are not available at stream outfalls
suspected of containing non-stormwater flows for use in calculating loads. To estimate
loads from each outfall for the TMDL, data from various dry weather flow investigations
were obtained from the Mecklenburg County Department of Environmental Protection
(Kroening, 2002). These data are described in the fecal coliform TMDL for Irwin,
McAlpine, Little Sugar, and Sugar Creek Watersheds approved in February 2002
(MCDEP/DWQ, 2002), and presented in Appendix 4.

A median dry weather flow rate of 0.00675 cfs from each outfall was calculated from the
Mecklenburg County studies based on an analysis of outfalls in the county possessing dry
weather flow. A geometric mean fecal coliform concentration in the dry weather flow of
676 cfu/100mL was also calculated from the Mecklenburg County data. These “typical”
flow and fecal coliform concentration values were applied to each outfall suspected of
containing non-stormwater flows in the upper North Buffalo Creek watershed in order to
calculate fecal coliform loads for each subwatershed. These loads are assumed to be
constant. Table 2.1.2.3 summarizes the loading estimates from illicit discharges (non-
stormwater flows) used in this TMDL.





















































































































































































Outfall location to 1:24,000 scale stream from
stormwater structure and/or pipe
Stormwater structure (e.g. inlet, manhole)
Pipe
Some discharge
outfalls for pipes in the downtown area are not verified/shown.

Final Report North Buffalo Creek Fecal Coliform TMDL 2.0 Source Assessment
21

Table 2.1.2.3 Fecal coliform loading estimates from illicit discharges (non-stormwater
flows) from the stormwater conveyance system.
Subwatershed
Number of
Outfalls to 1:24K
Scale Streams
Total Flow (cfs) 1 Total Load (#/day) 2
1 9 0.06075 1.01E+09
2 8 0.05400 8.94E+08
3 2 0.01350 2.23E+08
4 27 0.18225 3.02E+09
5 6 0.04050 6.70E+08
6.1 1 0.00675 1.12E+08
6.2 11 0.07425 1.23E+09
7 2 0.01350 2.23E+08
8 0 0.00000 0.00E+00
1 Total flow = Number of outfalls * 0.00675 cfs
2 Total load (#/d) = Total flow (cfs) * 676/100mL * conversion factor (24470000)

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Given the predominance of residential land
uses in the upper North Buffalo Creek
watershed, pets, specifically dogs and cats,
are believed to be potential significant
contributing sources of fecal coliform
loads in the watershed. The City of
Greensboro does not have a pet licensing
program, so dog and cat populations were
estimated based on national average pet
ownership statistics published by the
American Veterinary Medical Association
(AVMA 1997). The City of Wilmington,
NC conducted a comparison of pet
population estimates made using AVMA
statistics versus local county health
department records of registered pet
owners. Wilmington found that AVMA statistics yielded reasonably similar results for
watershed source assessment purposes (Wilmington, 2002). According to AVMA
statistics:

# of dogs in a given area = 0.534 * total number of households in the area

# of cats in a given area = 0.598 * total number of households in the area

Greensboro’s city parks, such as Latham Park shown
above along North Buffalo Creek, are popular places for walking dogs.
Final Report North Buffalo Creek Fecal Coliform TMDL 2.0 Source Assessment
22
2000 US Census block data, which includes household counts, were used to estimate the
number of households in each subwatershed which was then used in turn to estimate the
dog and cat population (Table 2.2.1.1).

Table 2.2.1.1 Estimated dog and cat population in the upper North Buffalo Creek
watershed based on AVMA statistics.
Subwatershed No. of Dogs No. of Cats No. of Households
1 3,047 3,412 5,706
2 2,063 2,310 3,863
3 356 398 667
4 3,742 4,190 7,007
5 710 795 1,330
6.1 816 914 1,528
6.2 1,495 1,674 2,800
7 1,475 1,652 2,762
8 0 0 0
Totals 13,704 15,345 25,663

Based on published animal feces production rates approximately 4,400 lb/day of feces is
generated from the dog population and 2,300 lb/day of feces is produced from the cat
population within the TMDL subwatersheds (CWP, 1999). Using input from the local
stakeholders group it was assumed for the purposes of this TMDL that 100% of the dog
waste generated is deposited outside, on residential land, and subject to rainfall runoff
processes. Fifty percent (50%) of cat waste was assumed to be deposited outside, on
residential land, and subject to runoff. Based on these data and assumptions, daily fecal
coliform accumulation rates were calculated as outlined in Table 2.2.1.2.

Table 2.2.1.2 Fecal coliform accumulation rates from pet waste.
Subwatershed
Accumulation Rate On
Residential Land 1
(count/acre/day)
(ACQOP)
Total Residential
Acreage
1 9.28 X 109 1,443
2 8.12 X 109 1,116
3 9.65 X 109 162
4 1.51 X 1010 1,086
5 1.20 X 1010 260
6.1 8.33 X 109 431
6.2 8.33 X 109 788
7 1.19 X 1010 546
8 0 0
1 Calculations based on a fecal coliform loading rate from dogs of 4.09E+09 cfu/dog/day (Roessler, 2002) and a rate from cats of 5.37E+08 cfu/cat/day (calculated from data provided in CWP, 1999).

Final Report North Buffalo Creek Fecal Coliform TMDL 2.0 Source Assessment
23

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The City of Greensboro operates over 1,382 miles of sanitary sewer lines ranging in size
from 6 to 72 inches in diameter. The sanitary sewer collection system transports
wastewater to either the North Buffalo Water Reclamation Facility (WRF) or the T.Z.
Osborne WRF on South Buffalo Creek. Both plants have advanced tertiary limits for
oxygen consuming wastes as permitted under NPDES.

The infiltration and inflow (I&I) of groundwater and/or rainwater into the sanitary sewer
collection system is an important management issue for municipalities. Excessive I&I
can result in sewer system overflows and reduced treatment capacity at the WWTP. The
City of Greensboro has an on-going inspection and maintenance program which includes
the rehabilitation of aging sewer lines. Over $1.7 million is spent annually on the
rehabilitation program with a particular focus on reducing I&I related problems. The
rehabilitation program also addresses exfiltration problems, i.e. when sewage is leaking
out of the collection system. Hydraulically this situation can occur when a sewer line is
above the water table or stream water
surface, or is under pressure as is the
case with force mains. Unfortunately,
exfiltration problems are much more
difficult to detect because often there is
little visual evidence that a problem is
occurring.

The majority of Greensboro’s sanitary
collection system (~97%) are lines
which generally follow the terrain to
take advantage of gravity flow. Hence,
by design collection arteries are often
located in close proximity to streams
and tributaries to transport wastewater
downhill to the treatment plant. This
situation presents an opportunity for
untreated sewage to reach a stream
through abnormalities in the line, such
as through cracks at a joint.

Most NC municipalities have very little
data for quantifying the degree of
exfiltration which is occurring from their sanitary sewer collection system. However, in
2000 Mecklenburg County published the results of a limited study designed to investigate
fecal coliform concentrations in groundwater in the vicinity of underground sanitary
sewer lines. The study is summarized in the Fecal Coliform TMDL for the Irwin,
McAlpine, Little Sugar, and Sugar Creek Watersheds (MCDEP/DWQ, 2002), and the
data presented in Appendix 5. Briefly, Mecklenburg County found that 3 out of 4 down
gradient wells, positioned near sewer lines located above the water table, had an average
groundwater fecal coliform concentration of 58 cfu/100mL. Measured concentrations
In the North Buffalo Creek watershed data on exfiltrating sanitary sewer lines are very limited, as is generally the case throughout NC. The best professional judgment of the local
TMDL stakeholders is that exfiltrating sanitary lines could be
a potential significant source of fecal coliform loads.
However, actual load contributions from this source are not well understood. A special study being conducted by the City of Greensboro on dry weather sources of fecal coliform
within the TMDL subwatersheds was initiated in the Spring of
2003. One of the goals of this study is to gather additional
information on this potential source to support implementation strategies.
Final Report North Buffalo Creek Fecal Coliform TMDL 2.0 Source Assessment
24
Sewer system overflow draining into North Buffalo Creek within subwatershed 4. The City of Greensboro maintains a database of SSOs as part of a program to minimize the occurrence of uncontrolled discharges
from the sanitary sewer collection system.
ranged from < 10 cfu/100mL to 1,700 cfu/100mL. None of the samples collected from
the 4 up gradient wells had measurable fecal coliform concentrations. None of the
samples collected from wells positioned near sewer lines located below the water table
had measurable fecal coliform concentrations.

For this TMDL exfiltrating sanitary sewer lines were simulated in the model as a constant
fecal coliform concentration in groundwater. Per the Mecklenburg County study,
groundwater concentrations for most of the subwatersheds were assumed to be 58
cfu/100mL. In subwatershed 4 which includes 215 acres of downtown area and some
turn of the century (1900s) residential development (see Figure 1.6.1), and in
subwatershed 7 which also has elevated instream fecal concentrations during dry weather,
groundwater concentrations were assumed to be 700 cfu/100mL. An assumed
groundwater concentration of 700 cfu/100mL is based primarily on model calibrations
during dry weather periods when loadings from most other sources are reduced. It is
important to note however that although the 700 cfu/100mL fecal coliform concentration
assumed for groundwater in selected subwatersheds is well within the range observed
within Mecklenburg County, there is no local data to substantiate this assumption. In
general, fecal coliform loads from exfiltrating sanitary sewer lines represent a significant
source of uncertainty in the TMDL. Exfiltrating sewer lines and other dry weather
sources of fecal coliform loads will be investigated in more detail as part of a special
study initiated in the spring of 2003 with funding from the Cape Fear River Assembly.

-&-&-&-&-&/
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Sewer system overflows can generally be
characterized as unpermitted discharges
from the sanitary sewer collection system.
To varying degrees SSOs occur in virtually
every municipal collection system. Often
SSOs are caused by excessive volumes of
rain water entering the collection system
which exceeds the systems capacity to
transport all the flow to the WWTP. SSOs
can also be caused by blockages in the lines
from grease, debris, tree roots, and other
obstructions.

The City of Greensboro’s Department of
Water Resources maintains a database of
spills and overflows from the sanitary
sewer collection system. The database
includes among other attributes the location, date and time the discharge started and
stopped, estimated discharge volume, whether or not the discharge reached a surface
water body, and an explanation of the possible cause of the discharge. Table 2.2.3.1 and
Figure 2.2.3.1 summarize the SSOs which occurred within the TMDL subwatersheds
during the model simulation period. Appendix 6 includes data for each individual SSO.

Final Report North Buffalo Creek Fecal Coliform TMDL 2.0 Source Assessment
25

Table 2.2.3.1 Summary of SSOs within the TMDL subwatersheds during the model
simulation period August 1998 through August 2001.
Subwatershed No. of SSOs Total Volume Spilled (gal)
1 25 5,575
2 18 3,875
3 1 200
4 42 72,115
5 7 2,780
6.1 14 1,615
6.2 13 6,950
7 11 7,325
8 0 0
Total 131 100,435

Figure 2.2.3.1 Distribution of SSOs within the TMDL subwatersheds during the period
August 1998 through August 2001.

Loads from SSOs were estimated based on an assumed fecal coliform concentration in
untreated sewage of 6.4X106 cfu/100mL (CWP, 1999), and flow rates calculated from the
spill start and stop times and estimated spill volume reported in the SSO database.
Within the model framework, fecal coliform loads from SSOs are simulated as direct
discharges to a stream reach. Start and stop times for each individual SSO are maintained
within the model.










































































































































































































































































































Location of SSO

Note: In some cases more than one overflow has occurred at a given location.
1
2
3
4
5
6.1
6.2 7
8
Final Report North Buffalo Creek Fecal Coliform TMDL 2.0 Source Assessment
26

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On-site wastewater treatment systems are a very common means of treating and deposing
of wastewater in areas of NC not served by a centralized sanitary sewer system. Since all
of the area within the TMDL subwatersheds is within the Greensboro city limits, septic
systems were not believed to be in common use. However, even in urban areas it is
possible for these systems to be in existence and thus were considered as part of the
TMDL analysis.

No direct accounting of the number of septic systems in use within the TMDL
subwatersheds is available. Therefore, in order to quantify loads from improperly
functioning (failing) septic systems, the total number of systems in use had to be
estimated. This was accomplished through an analysis of water and sewer billing records
maintained by the Greensboro Department of Water Resources. Based on a comparison
of these records, it was assumed that city customers with developed properties receiving a
water bill but not a sewer bill, were disposing wastewater via an on-site system. There
are no NPDES permitted privately owned package plants within the TMDL
subwatersheds.

Based on the collective experience of the TMDL stakeholders an estimated failure rate of
10% – 20% was believed to be appropriate. This range was corroborated by the opinion
of an experienced septic system inspector with the Guilford County Health Department
(Edwards, 2002). Table 2.2.4.1 and Figure 2.2.4.1 summarize the septic system source
assessment.

Table 2.2.4.1 Septic systems within the TMDL subwatersheds.
Subwatershed Estimated Total Number
of Septic Systems
Estimated Number of Failing
Septic Systems 1
1 9 1
2 9 1
3 2 0
4 22 4
5 3 0
6.1 1 0
6.2 7 1
7 3 0
8 0 0
Total 56 7
1 The number of failing septic systems was estimated by assuming a 15% failure rate from the total number of systems and rounding to the nearest integer. In the case of subwatershed 4 the number of failing systems was rounded up to the nearest integer, as this subwatershed had a
disproportionately high number of systems.

Final Report North Buffalo Creek Fecal Coliform TMDL 2.0 Source Assessment
27

Figure 2.2.4.1 Distribution of septic systems within the TMDL subwatersheds.

Fecal coliform loads from failing septic systems were calculated by assuming 2.3
individuals are served by each septic system which is based on the average number of
persons in a Greensboro household according to the 2000 US Census. A per capita flow
rate of 70 gallons per person per day, and a fecal coliform concentration of 10,000
cfu/100mL was assumed for the loading calculations (Horsely and Whitten, 1996). Table
2.2.4.2 summarizes the estimated fecal coliform load from failing septic systems within
the TMDL subwatersheds.

Table 2.2.4.2 Estimated fecal coliform load from failing septic systems located within the
upper North Buffalo Creek watershed.
Subwatershed No. of Failing
systems Flow (cfs) FC Concentration in
Effluent (#/100mL)
FC Load
(#/day)
1 1 0.00025 10,000 6.09E+07
2 1 0.00025 10,000 6.09E+07
3 0 0.00000 10,000 0.00E+00
4 4 0.00100 10,000 2.44E+08
5 0 0.00000 10,000 0.00E+00
6.1 0 0.00000 10,000 0.00E+00
6.2 1 0.00025 10,000 6.09E+07
7 0 0.00000 10,000 0.00E+00
8 0 0.00000 10,000 0.00E+00
Totals 7 0.00174 4.27E+08





































































































Unverified septic system location based on an analysis of water and sewer billing records
Final Report North Buffalo Creek Fecal Coliform TMDL 2.0 Source Assessment
28





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-&1
-&1
-&1




; ; ; ;

Within the City of Greensboro there are
over 580 ponds and lakes.† Due in part to
the large number of open waterbodies in
the area, the City of Greensboro supports a
sizable waterfowl population, particularly
Canada geese and mallard ducks.

According to data published by the
National Audubon Society, over 10,400
sightings of Canada geese and 6,300
sightings of mallards have been recorded
in the Greensboro area during the annual
Christmas Bird Counts for the period
1991-2001 (Audubon, 2003). The 2001
one-day Greensboro Audubon count
included 1,341 Canada geese. Many NC geese populations are no longer migratory due
to the year round availability of food. Geese are primarily terrestrial feeders, often seen
harvesting grass and seeds along maintained lawn areas surrounding ponds, lakes, and
golf courses. In recent decades, non-migratory geese populations have been a growing
problem in these maintained areas because of the quantity of feces deposited by the birds.

In an effort to compile site specific data on geese and mallard populations within the
TMDL subwatersheds, several locations mostly associated with lakes and ponds, were
investigated for evidence of significant waterfowl populations. Table 2.2.5.1 outlines the
locations investigated.

Table 2.2.5.1 Locations investigated for evidence of waterfowl populations in the upper
North Buffalo Creek watershed. Survey conducted on 10/23/02.
Subwatershed Location Comment
1 Lake Hamilton Evidence of significant waterfowl
populations.
1 Lake Euphemia Access very limited due to surrounding
private property.
1 Starmount CCGC No evidence of significant waterfowl
populations.
1
Starmount Park,
Lindley Park,
Arboretum
No evidence of significant waterfowl
populations.
2 Bog Garden
Large year round waterfowl population
according to a volunteer park naturalist.
Ducks and geese fed daily by park visitors.
2 Bicentennial Garden No evidence of significant waterfowl
populations.

† Data based on an inventory of open waterbodies conducted during the stormwater infrastructure mapping
project. Ponds include both natural and engineered wet detention ponds designed as water quality BMPs.
Canada geese feeding near the banks of North Buffalo
Creek near Church St.
Final Report North Buffalo Creek Fecal Coliform TMDL 2.0 Source Assessment
29
4 Lake Daniel No evidence of significant waterfowl
populations.
4 Greensboro CCGC No evidence of significant waterfowl
populations.
4 UNC-G golf course
practice holes
No evidence of significant waterfowl
populations.
6.2 Buffalo Lake Evidence of significant waterfowl
populations.
6.2 Private pond at Irving
Park Village
Evidence present of problematic waterfowl
populations but few birds observed.
7 Pond near Mizell Rd. No evidence of significant waterfowl
populations.
7 Pond at Craft Rec.
Center near Leo Dr.
No evidence of significant waterfowl
populations.

Of the sites described in Table 2.2.5.1 Lake Hamilton, the Bog Garden, and Buffalo Lake
were identified as the locations most likely to support year round populations of
waterfowl. It is important to note that waterfowl populations are constantly changing
over space and time, however these three
locations appear most likely to support
sizable populations for inclusion in the
TMDL. Figure 2.2.5.1 illustrates the
locations of these three waterfowl sites.

Figure 2.2.5.1 Lakes and ponds in the
upper North Buffalo Creek watershed
identified as likely supporting significant
year-round waterfowl populations.

The Bog Garden Park pond, shown in the above two pictures, supports a relatively large year-round waterfowl population for its size. Many of the ducks and geese have
become “tame” from routine feedings from park visitors.



Buffalo Lake
Bog Garden
Lake Hamilton
Final Report North Buffalo Creek Fecal Coliform TMDL 2.0 Source Assessment
30

To calculate fecal coliform loads for the TMDL, waterfowl populations from the three
locations were estimated by averaging survey data collected on 10/23/02 (and 11/8/02 for
Buffalo Lake) with 10 years of National Audubon Society Christmas Bird Count data
(1991-2001). Based on data from the National Audubon Society available from their
website, the average annual Audubon one-day count for geese in the Greensboro area is
949 and for mallards is 578 (Audubon, 2003).

For the purposes of estimating how many waterfowl might be residing at the three
locations of interest for this TMDL, it was assumed that the average Audubon
populations are evenly distributed across open waterbodies within Greensboro (including
the water supply reservoirs which border the city’s northern edge). Based on the city-
wide stormwater infrastructure GIS mapping project discussed in Section 2.1.2, there are
approximately 3,320 acres of open waterbodies (lakes, ponds, and reservoirs) in the
Greensboro area. These data were used to calculate areal weighted average waterfowl
populations for the three waterbodies of interest in the TMDL as described in Table
2.2.5.2.

Table 2.2.5.2 Estimated waterfowl populations for three locations identified within the
TMDL subwatersheds as likely supporting year-round populations.
Subwatershed Location 10/23/02
Survey 1
11/8/02
Survey 1
Audubon
Areal
Weighted
Average 2
Average
Populations
Assumed for
TMDL 3
1 Lake Hamilton Geese: 0
Ducks: 22 n/a Geese: 5
Ducks: 3
Geese: 2.5
Ducks: 12
2 Bog Garden Geese: 10
Ducks: 42 n/a Geese: 4
Ducks: 2
Geese: 14
Ducks: 22
6.2 Buffalo Lake Geese: 20
Ducks: 4
Geese: 0
Ducks: 57
Geese: 26
Ducks: 15
Geese: 15
Ducks: 25
1 Observed waterfowl population in and adjacent to the waterbody based on a count conducted over roughly a one hour time period.
2 Areal weighted averages were calculated by assuming that the average annual Audubon bird count populations are
evenly distributed over Greensboro’s 3,320 acres of open waterbodies. The resulting bird/acre ratio was multiplied by
the area of the three waterbodies of interest within the TMDL subwatersheds to estimate geese and duck populations. 3 This column represents the populations used for calculating fecal coliform loads from waterfowl for the TMDL. These numbers represent an arithmetic average of the survey data and Audubon data.

Final Report North Buffalo Creek Fecal Coliform TMDL 2.0 Source Assessment
31

Tables 2.2.5.3 through 2.2.5.5 summarize fecal coliform loading rates from waterfowl
populations at Lake Hamilton, the Bog Garden, and Buffalo Lake.

Table 2.2.5.3 Estimated fecal coliform loads from waterfowl populations at Lake Hamilton.
Waterfowl Population
Daily FC
Loading Rate
(#/bird/day) 1
% of Load
Deposited
Directly in
Waterbody 2
FC Load
Deposited
Directly in
Water (#/day) 3
FC Load
Deposited
on Land
(#/day)
Geese 2.5 4.90 X 1010 5% 3.06 X 108 1.16 X 1011
Ducks
(mallards) 12 2.43 X 109 80% 1.17 X 109 5.83 X 109
1 Source: Roessler, 2002. 2 Percentages based on best professional judgment estimates of the percentage of time each species spends in the water.
3 Estimates of the load deposited directly in the water factors in a 95% removal efficiency for the waterbody.

Table 2.2.5.4 Estimated fecal coliform loads from waterfowl populations at the Bog Garden.
Waterfowl Population
Daily FC
Loading Rate
(#/bird/day)
% of Load
Deposited
Directly in
Waterbody
FC Load
Deposited
Directly in
Water (#/day) 1
FC Load
Deposited
on Land
(#/day)
Geese 14 4.90 X 1010 5% 3.43 X 109 6.52 X 1011
Ducks
(mallards) 22 2.43 X 109 80% 4.28 X 109 1.07 X 1010
1 Estimates of the load deposited directly in the water factors in a 90% removal efficiency for the waterbody.

Table 2.2.5.5 Estimated fecal coliform loads from waterfowl populations at Buffalo Lake.
Waterfowl Population
Daily FC
Loading Rate
(#/bird/day)
% of Load
Deposited
Directly in
Waterbody
FC Load
Deposited
Directly in
Water (#/day) 1
FC Load
Deposited
on Land
(#/day)
Geese 15 4.90 X 1010 5% 1.84 X 109 6.98 X 1011
Ducks
(mallards) 25 2.43 X 109 80% 2.43 X 109 1.22 X 1010
1 Estimates of the load deposited directly in the water factors in a 95% removal efficiency for the waterbody.

Final Report North Buffalo Creek Fecal Coliform TMDL 2.0 Source Assessment
32

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During the development of this TMDL a significant amount of effort has been directed
towards explicitly accounting for likely sources of fecal coliform loads in the upper North
Buffalo Creek watershed. Explicitly identifying sources is an important step towards the
ultimate implementation of successful load reduction strategies.

However, it should be recognized that it is not possible to explicitly account for every
source of fecal coliform loading in the watershed - as the potential number of individual
source types is huge and site specific data much too scarce. Therefore, these other
sources, which are surely in the watershed but are not individually identifiable, have been
lumped into a category known as Other (unidentified) sources. For the purposes of this
TMDL loads from unidentified sources are assumed to be land deposited and nonpoint
source in nature. The load delivery mechanism to the stream is simulated in the model by
rainfall runoff-type processes.

Final Report North Buffalo Creek Fecal Coliform TMDL 3.0 Modeling Approach
33

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Water quality computer models are frequently used during TMDL development for
establishing a relationship between instream water quality conditions and the contributing
watershed. These models use mathematical equations to represent the important physical
and chemical processes which are believed to affect the environment. By necessity
models are simplified versions of reality, as the environment is much too complex to
fully simulate with mathematics. However, models have proven over time to be very
useful tools for gaining a better understanding of the cause-effect relationship between
pollutant loadings and the water quality issues we are concerned about.

The TMDL modeling process typically proceeds in two distinct phases. The objective of
the first phase is to simulate existing water quality conditions. Once the model is deemed
to be adequately simulating existing conditions (referred to as a calibrated model), then
the second modeling phase can begin. In the second phase, the objective is to evaluate
various pollutant load reduction strategies in order to achieve a water quality goal –
which is typically the achievement of state numeric water quality standards.

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EPA’s Hydrologic Simulation Program – Fortran (WinHSPF version 2.0.6) was chosen
as the modeling platform for development of this TMDL. WinHSPF is a public domain
watershed model maintained and distributed by the US EPA. WinHSPF is a continuous
simulation, precipitation-drive model designed to calculate point and nonpoint source
pollutant loadings, downstream transport, and instream pollutant decay.

In the world of water quality models, WinHSPF is generally considered a relatively
complex, highly parameterized model. These same characteristics also make WinHSPF a
relatively flexible model for addressing a variety of pollutant and water quality issues.
While this TMDL solely addresses fecal coliform, the Greensboro Stormwater
Management Division desired a flexible modeling platform for addressing other water
quality issues in the North Buffalo Creek watershed as the need arises, hence the
selection of WinHSPF.

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EPA’s BASINS 3.0 GIS interface was used to set up the initial WinHSPF user input file.
Given the relatively large amount of detailed local data available, most of the GIS layers
packaged with BASINS 3.0 were not used as part of the model setup. Below is a
description of the basic model setup.

Final Report North Buffalo Creek Fecal Coliform TMDL 3.0 Modeling Approach
34
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The upper North Buffalo Creek watershed was delineated into nine subwatersheds,
corresponding to the various water quality & stream flow monitoring stations, and to
selected hydrologic features such as Lake Buffalo (refer to Sections 1.3 and 1.8 for
additional details). One stream reach is simulated within each subwatershed. Most of the
information needed for estimating stream reach length, slope, and cross sectional
dimension was adopted from the GIS stormwater conveyance system mapping project
described in Section 2.1.2. As part of this project 169 surveyed cross sections were
conducted on the mainstem and tributaries within the TMDL subwatersheds. The cross
section database was reviewed and stream dimension data deemed representative of the
reach as a whole was incorporated into the model. Stage-discharge relationships were
estimated using Mannings equation.

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Most of the meteorological data used by the model, except precipitation, was collected at
the Piedmont Triad International Airport (PTIA), and obtained from the National
Climatic Data Center in Asheville, NC. PTIA is located approximately 3.4 miles west of
the headwaters of the North Buffalo Creek
watershed. Precipitation data (15 minute interval)
collected at the USGS Church Street rain gage
(02095271) were used to supplement the PTIA
meteorological data for the model. The Church
Street rain gage is centrally located within the upper
North Buffalo Creek watershed and has the longest
period of record (beginning in August 1998) of the
two rain gages in the watershed. Precipitation data
from the USGS rain gage at Westover Terrace
(02095181) was used to fill gaps in the Church
Street precipitation record when that gage was
down due to maintenance or malfunction. The
Westover Terrace gage is located approximately 2.1
miles southwest of the Church Street gage.

Having local precipitation data collected within the
watershed is a big advantage during model
calibration of stream flow. In the piedmont of NC,
summertime thunderstorms can result in
significantly different precipitation amounts over
relatively short distances. For example, on 6/19/00
the following daily rainfall totals were recorded at the three gages:

PTIA gage: 0.32 in
Westover Terrace gage: 2.69 in
Church Street gage: 3.22 in
USGS stream flow and precipitation gaging station on North Buffalo Creek at Church Street. This and other gaging stations in the
area are operated with support from
Greensboro’s Department of Water Resources.
Final Report North Buffalo Creek Fecal Coliform TMDL 3.0 Modeling Approach
35
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A continuous model simulation period from August 1, 1998 to August 1, 2001 was used
for the TMDL analysis. The TMDL simulation period start time corresponds to the
earliest available daily stream flow and precipitation data from the USGS gage at Church
St. This time window also corresponds to the period when the majority of instream fecal
coliform data within the TMDL subwatersheds were collected.

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Sections 1.5 and 1.7 describe in detail the land use/land cover data and impervious
surface estimates used to set up the model. In summary, these data sets were based
primarily on 2000 orthophotography and numerous updated GIS planimetric data layers.
On balance, the TMDL subwatersheds are dominated by residential land uses (>41%) and
have an average percent impervious surface coverage of approximately 26%. The vast
majority of the residential development was constructed between 1920-1970, with some
turn-of-the-century residential areas mostly concentrated adjacent to the downtown area.

The total area of open waterbodies in most of the subwatersheds comprised <1% of the
total subwatershed area. Hence, these small ponds were not explicitly simulated in the
model, and were treated as another 100% pervious land cover type. However, in
subwatershed 6.2 Buffalo Lake comprises 6% of the subwatershed area and was
explicitly simulated in the model as a lake.

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Buffalo Lake in subwatershed 6.2 is an industrial water supply reservoir for the Cone
Mills textile manufacturing facility. Based on an analysis of water withdrawal
registration records obtained from the NC Division of Water Resources for the calendar
year 1999, the monthly average withdrawal rate from Buffalo Lake averages 115% of the
monthly average wastewater discharge rate (DWR, 2002). For model simulation
purposes, it was assumed that the daily average withdrawal rate was also 115% of the
daily discharge rate. Appendix 3 outlines daily discharge rates for the Cone Mills
WWTP.

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The fecal coliform source assessment described in Part 2 details the eight source
categories and load quantification methods used for the TMDL. This section outlines
how these data were incorporated within the WinHSPF modeling framework.

Both point and nonpoint sources are represented in the model using various methods.
Several nonpoint source categories are not associated with land loading processes and
Final Report North Buffalo Creek Fecal Coliform TMDL 3.0 Modeling Approach
36
thus are represented in the model as direct inputs into the stream. These sources include
SSOs, failing septic tanks, and a portion of the waterfowl load contribution. Land
loading nonpoint sources are represented as indirect contributions to the stream through
build-up and wash-off processes. These sources include pets, a portion of the waterfowl
load contribution, and the Other Sources category.

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Cone Mills is the sole NPDES permitted wastewater discharger within the TMDL
subwatersheds which contributes fecal coliform loads. The discharge is represented as a
point source with direct input to the mainstem in subwatershed 8. Daily measurements of
flow and fecal coliform concentration as reported in the facilities NPDES Discharge
Monitoring Reports were used to calculate daily variable loads. For those days (e.g.
weekends) for which no fecal coliform concentration data were reported, a concentration
equal to the average of the two most recent samples preceding, and the two most recent
samples following, the missing data day were assumed. For example, if no fecal coliform
data were reported for a Saturday and Sunday then those missing values were filled by
calculating the average fecal coliform concentration from samples collected on Thursday,
Friday, Monday, and Tuesday. Section 2.1.1 provides additional details on the Cone
Mills WWTP, and Appendix 3 includes the complete effluent flow and fecal coliform
dataset used to simulate the discharge.

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Section 2.1.2 provides additional information on the 102 stormwater conveyance
structures (e.g. manholes and pipes) suspected of having an elevated chance of
transporting an illicit discharge. Flow passing through these structures ultimately drain to
66 stream outfalls. Since the locations of these outfalls are known, the number in each
subwatershed is also known. Since WinHSPF simulates one stream reach per
subwatershed, the loads from each outfall within a given subwatershed were added
together and combined into a single direct discharge to the reach.

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Given the relatively high percentage of residential land uses in the upper North Buffalo
Creek watershed pets, specifically dogs and cats, are suspected to be a potential
significant contributor of fecal coliform loads. Section 2.2.1 describes the process used
for estimating pet populations in the TMDL subwatersheds. Based on an estimate of dog
and cat populations within each subwatershed, a daily fecal coliform accumulation rate
was calculated (Table 2.2.1.2). This accumulation rate was applied to all single and
multifamily residential lands, but not to any other land cover classes. The accumulation
rate on residential lands was not changed during the water quality calibration process.

Final Report North Buffalo Creek Fecal Coliform TMDL 3.0 Modeling Approach
37

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In the model exfiltrating sanitary sewer lines are assumed to be leaking sewage into the
ground and delivering pollutant loads to the stream via groundwater inflow. WinHSPF
allows a constant fecal coliform concentration in groundwater to be assigned to each
subwatershed. Loads from exfiltrating sewer lines vary over time based on the volume of
groundwater entering a stream reach. Section 2.2.2 provides additional details on this
source and groundwater concentrations of fecal coliform used in the model.

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For this TMDL SSOs were classified as time variable (hourly) nonpoint sources which
directly discharge into the stream. For modeling purposes, all SSOs which occurred
within a given subwatershed were grouped into a single time variable discharge for that
subwatershed. No SSOs occurred within subwatershed 8 during the model simulation
period. The discharge was assumed to start and stop according to the event start and stop
times within the City’s SSO database. The total discharge duration time was rounded up
to the nearest whole hour. For the few records in which a start or stop time was not
indicated a 3 hour discharge duration was assumed. Section 2.2.3 provides additional
details and loading information from this source. Appendix 6 includes the complete SSO
dataset used in the model.

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Fecal coliform loads from failing septic systems were simulated in the model as a
continuous direct discharge into a stream reach. Loads did not vary over time but were
allowed to vary spatially depending on the estimated number of failing systems within a
given subwatersheds. Similar to SSOs and illicit discharges, multiple discharges from
failing septic systems within a given subwatershed were combined into a single discharge
for that subwatershed. Section 2.2.4 provides additional details and loading information
from this source.

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Unlike the sources described above, loads from ducks and geese were partitioned into
both loads directly discharged into a stream reach, and into land applied loads subject to
build-up and wash-off processes. This approach was taken because geese spend the
majority of the day on land feeding (and defecating), whereas ducks tend to spend most
of their time in the water. Based on a field survey of favorable waterfowl habitat
described in Section 2.2.5, only subwatersheds 1, 2, and 6.2 received direct instream fecal
coliform loads from waterfowl in the model.

Final Report North Buffalo Creek Fecal Coliform TMDL 3.0 Modeling Approach
38
Buffalo Lake is impounded by an earthen dam covered in grass which is routinely mowed
and is prime geese habitat. The dam forms the divide between subwatersheds 6.2 and 7.
Based on field observations the majority of the dam area covered in grass appears to
drain into subwatershed 7 as opposed to the lake. Thus, the land applied fecal coliform
load from waterfowl associated with Buffalo Lake was input into subwatershed 7.

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As discussed in section 2.2.6 it is not possible to explicitly identify all sources of fecal
coliform in the watershed. However, it is recognized that other potential sources do
likely exist. Sources which were not individually identifiable were lumped into a
category labeled unidentified sources. For the purposes of this TMDL, loads from
unidentified sources are assumed to be land deposited and nonpoint source in nature. The
load delivery mechanism to the stream was simulated in the model by build-up and wash-
off type processes. An accumulation rate from these sources was assigned to each land
cover type, except for residential types - MF & RES, and WATER. Since by definition it
is not possible to estimate the population of unidentified sources, the accumulation rate
was used as a water quality calibration parameter.

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Model calibration is the process of tuning or adjusting the various model parameters in
order to obtain an optimal agreement between the model calculations and the observed
monitoring data. Calibration of a dynamic watershed model such as WinHSPF involves
tuning both hydrologic and water quality components. Since WinHSPF is driven by
precipitation and the subsequent treatment of the water budget, the process of calibration
begins with adjusting the model’s hydrologic parameters to achieve a best fit between
predicted and observed stream flows. After the model’s hydrologic calibration has been
deemed satisfactory then the water quality calibration process begins.

Once calibrated, the model was confirmed by comparing predictions against a new set of
observed data not used during calibration. During the confirmation period the physical
forcing parameters, such as the meteorological data, are changed to reflect the new
conditions but the model’s hydrologic and water quality parameters remain fixed at the
values set during the calibration process. A model that agrees with the observed data
during the confirmation period can be used with greater confidence to make management
decisions. Table 3.4.1 outlines the calibration and confirmation periods specified during
model development.
Final Report North Buffalo Creek Fecal Coliform TMDL 3.0 Modeling Approach
39

Table 3.4.1 Model calibration and confirmation periods.
Model Development Phase Period Comment
Calibration August 1, 1998 –
August 1, 2000
Calibration start date corresponds to the
earliest available USGS flow gaging data
within the TMDL subwatersheds (Church
St. gage – 02095271).
Confirmation August 2, 2000 –
August 1, 2001 One year confirmation period.

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In the hydrologic calibration simulated stream flows were compared to the observed
stream flow at two USGS continuous recording stations on the North Buffalo Creek
mainstem within the TMDL subwatersheds (see Figure 1.8.1 for a map of the station
locations). Hydrologic parameters, including infiltration, upper and lower zone storage,
groundwater storage and recession, interflow, and evapotranspiration, were adjusted
within EPA recommended ranges (USEPA, 2000). Table 3.4.1.1 summarizes the
hydrologic calibration statistics for reach 4 at Church Street - the downstream most
USGS gaging station within the TMDL subwatersheds. Figure 3.4.1.1 and 3.4.1.2
illustrate predicted and observed flows at Church St.
Final Report North Buffalo Creek Fecal Coliform TMDL 3.0 Modeling Approach
40

Table 3.4.1.1 Hydrologic calibration statistics for reach 4 at the Church Street USGS gage.

Calibration period: 8/1/98 – 8/1/00 Contributing area to subwatershed 4 outlet (mi2): 14.3

Predicted Flow Volumes 1 Observed Flow Volumes 1
Total predicted instream flow: 35.6 Total observed instream flow: 32.9

Total of highest 10% flows: 19.5 Total of highest 10% flows: 17.3
Total of lowest 50% flows: 4.2 Total of lowest 50% flows: 4.2
Total of lowest 25% flows: 1.5 Total of lowest 25% flows: 1.3

Predicted Summer Flow Volume
( months 7-9): 9.4
Observed Summer Flow Volume
( months 7-9): 8.8
Predicted Fall Flow Volume
(months 10-12): 6.3
Observed Fall Flow Volume
(months 10-12): 5.7
Predicted Winter Flow Volume (months 1-3): 9.9 Observed Winter Flow Volume (months 1-3): 9.1
Predicted Spring Flow Volume
(months 4-6): 10.0
Observed Spring Flow Volume
(months 4-6): 9.3

Prediction Error (predicted – observed) Recommended Criteria 2
Error in total volume: 7.7% 10%
Error in 50% lowest flows: 0.7% 10%
Error in 10% highest flows: 11.4% 15%
Seasonal volume error - Summer: 7.2% 30%
Seasonal volume error - Fall: 8.9% 30%
Seasonal volume error - Winter: 7.8% 30%
Seasonal volume error - Spring: 7.3% 30%
Standard error 3: 0.19
R2 3: 0.815
Observed mean 3: 0.95
Number of observations: 732

1 Flow volumes in inches normalized by watershed area. 2 Adopted from the USGS HSPEXP – Expert System for Calibration of HSPF (USGS, 1994).
3 Statistics using log base 10.
Final Report North Buffalo Creek Fecal Coliform TMDL 3.0 Modeling Approach
41

Figure 3.4.1.1 Observed versus predicted flows at Church Street (Reach 4).
(Units: Precipitation in inches and flow in cfs)

Figure 3.4.1.2 Frequency distribution of observed and predicted stream flows at Church
Street during the calibration period (8/1/98 – 8/1/00).
Calibration Period Confirmation Period
Calibration Period Confirmation Period
Calibration Period Confirmation Period
Final Report North Buffalo Creek Fecal Coliform TMDL 3.0 Modeling Approach
42

Figures 3.4.1.3 and 3.4.1.4 illustrate observed and predicted flows at Westover Terrace –
the upstream most USGS gaging station.

Figure 3.4.1.3 Observed versus predicted flows at Westover Terrace (Reach 3).
Note: Westover Terrace gage began operation in June 1999.
(Units: Precipitation in inches and flow in cfs)

Figure 3.4.1.4 Frequency distribution of observed and predicted flows at Westover
Terrace (Reach 3) during the calibration period.

Calibration Period Confirmation Period
Final Report North Buffalo Creek Fecal Coliform TMDL 3.0 Modeling Approach
43
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After the hydrologic calibration was completed the model was calibrated for water
quality (fecal coliform) by adjusting model parameters within appropriate limits until an
acceptable agreement between simulation output and instream observed data was
achieved. The key model variables adjusted include:

···· Rate of accumulation of fecal coliform on land (ACQOP)
···· Maximum storage of fecal coliform (SQOLIM)
···· Rate of surface runoff which will remove 90% of stored fecal coliform (WSQOP)
···· Concentration of fecal coliform in interflow outflow (IOQC)
···· Concentration of fecal coliform in groundwater outflow (AOQC)

Fecal coliform is one of the more challenging water quality parameters to accurately
model. Observed instream fecal coliform concentrations, particularly in stormwater
runoff, are notoriously variable. This is due in part to the fact that most concentrations
represent a grab sample (discrete point in time) rather than a true flow composite
sample.† In addition, there is often a significant amount of measurement variability
when samples are counted. It is not unusual to find a one or more fold difference in
reported fecal coliform concentrations between split samples. The transient nature of
many of the sources, such as illicit discharges, also adds to the modeling challenge.

For these reasons and others, the water quality calibration strategy was to achieve
agreement with general patterns in the observed data, rather than to attempt to fit the
model output to individual instream observations. As subject to the available data,
calibration proceeded in an upstream to downstream fashion. Additional emphasis was
placed on the water quality calibration during dry weather (ambient) conditions, as this is
generally the period of highest risk of exposure to pathogens by recreational users, and
thus the period when most of the observed data has been collected (refer to Section 1.9
for a summary of the observed data).

Since TMDLs are designed to identify maximum loads a stream can assimilate and still
meet water quality targets, it is helpful to compare predicted and observed loads. Daily
fecal coliform loads (#/day) are calculated by taking the product of concentration
(#/100mL), flow (cfs), and a conversion factor (24465755). Figure 3.4.2.1 illustrates
predicted and observed daily fecal coliform loads at Summit Avenue during the
calibration period. Since there is not a flow gage at Summit Avenue, modeled flows
combined with observed fecal coliform concentrations measured by the Cone Mills
WWTP were used to calculated observed fecal coliform loads. Note from the figure that
a trend line reflecting the least squares fit through the observed data points suggest that
the observed loads tend to be over the predicted allowable load (based on 200
cfu/100mL) throughout the various flow regimes. The departure from the allowable load
tends to be greatest during high and transition flows and least during low flows.

† Holding time restrictions often make composite sampling for fecal coliform impractical.
Final Report North Buffalo Creek Fecal Coliform TMDL 3.0 Modeling Approach
44

Figure 3.4.2.1 Observed and predicted fecal coliform loads at Summit Avenue during the
calibration period (August 1998 – August 2000).

Note from Figure 3.4.2.1 that the predicted loads generally follow the trend of the
observed loads over the spectrum of flows - indicating that the model can be used within
reasonable bounds for supporting management decisions. Note though that the model
does not predict well the lowest daily loads (<4.0 X 1011). This is due in part to the fact
that several of the modeled sources (such as illicit discharges, failing septic systems, and
a portion of the waterfowl load) are represented as continuous, non-varying loads into a
stream reach. This has the effect in the model of “establishing” a minimum load level
during non-stormwater runoff periods. In reality, however, dry weather loads are not
constant over time. For example, illicit discharges are often very transient in nature and
vary tremendously in magnitude over time. The sporadic “low” observed loads over the
various flow conditions could be a reflection of the transient nature of the actual loads
throughout the watershed. Representing selected sources as continuous, non-varying
loads is a conservative modeling assumption which is part of the implicit margin of safety
built into the TMDL (refer to Part 4 for addition discussion on the margin of safety).

It important to note that during the source assessment phase of the TMDL, the best
available data were used to estimate loads from the various known sources. During
model calibration these loads were not altered for the purposes of fitting the observed
data.†

† The one identified source which is an exception to this statement is exfiltrating sanitary sewer lines.
Loads from this source in subwatersheds 4 and 7 were varied from initial estimates when it became
apparent that predicted instream FC concentrations were being underestimated. The lack of local data on














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Final Report North Buffalo Creek Fecal Coliform TMDL 3.0 Modeling Approach
45

Table 3.4.2.1 is a comparison of geometric means between predicted and observed fecal
coliform concentrations over four stream flow regimes during the calibration period.

Table 3.4.2.1 Predicted geometric means over four flow regimes.1

1 High flows: 559 (modeled peak) – 70 cfs; Transition flows: 69 – 22 cfs; Typical flows: 21 - 10 cfs; Low flows: 9 – 3.4 (modeled low) cfs

exfiltrating sewer lines is a significant source of uncertainty in the model. Targeted field studies
associated with this source are being planned to support implementation strategies.
Predicted Geometric Mean
FC Concentration (#/100mL)
Observed Geometric Mean
FC Concentration (#/100mL)
High flows : 3,172 High flows : 1,790
Transition flows : 1,887 Transition flows : 736
Typical flows : 443 Typical flows : 423
Low flows : 390 Low flows : 209
Final Report North Buffalo Creek Fecal Coliform TMDL 4.0 Total Maximum Daily Load
46

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A TMDL is the calculation of the maximum amount of pollutant loading that a receiving
waterbody can assimilate while still achieving water quality standards. TMDLs include
an allocation of that amount among point and nonpoint sources. In total a TMDL is
comprised of the sum of wasteload allocations (WLA) for point sources, load allocations
(LA) for nonpoint sources, and a margin of safety (MOS). This definition can be
expressed as:

TMDL =
WLA +
LA + MOS

where:
WLA is the sum of the allowable loads from point sources and;

LA is the sum of the allowable loads from nonpoint sources and;
MOS is the Margin of Safety

The margin of safety is intended to be an accounting of uncertainty about the relationship
between pollutant loads and receiving water quality. The MOS in a TMDL can be
provided implicitly through conservative analytical/modeling assumptions, or explicitly
by reserving a portion of the assimilative capacity, or a combination of both methods
(USEPA, 2000a).

Traditionally, geographically diffuse stormwater driven sources of fecal coliform have
been classified as nonpoint sources of pollution. Compared to WWTP discharges, which
in many respects have been the comparative basis for the definition of a point source,
sources such as pets have generally been considered nonpoint sources.

In November 2002 EPA headquarters published guidance which clarifies the regulatory
requirements for establishing wasteload allocations for stormwater discharges (USEPA,
2002). In summary, this guidance states that sources which are transported to a stream
via a NPDES regulated stormwater system must be considered point sources, and thus be
addressed in the wasteload allocation component of a TMDL. Since Greensboro is an
NPDES Phase I community, pollutant loads from pets for instance, which are discharged
to a stream reach via the stormwater conveyance system, must be considered as point
sources. Pollutant loads from pets not discharged through the stormwater conveyance
system can be considered nonpoint sources, and thus addressed by the load allocation
component of a TMDL.

Since some runoff delivered sources, such as pets, are mobile and therefore impractical to
determine the load delivered through the stormwater conveyance system using field data,
a generic yet defensible method was needed to partition the WLA and the LA. In an
effort to meet the EPA guidance, and after considering several alternatives, the
stakeholders group decided to use the average impervious surface coverage within the
TMDL subwatersheds, which is 26%, as the method for partitioning loads from runoff
Final Report North Buffalo Creek Fecal Coliform TMDL 4.0 Total Maximum Daily Load
47
driven sources between the WLA and LA categories. Since most of the impervious
surfaces within the TMDL subwatersheds are connected to the NPDES permitted
stormwater conveyance system, the consensus opinion of the stakeholders was that this
method is reasonable and defensible. Table 4.0.1 summarizes the load percentage
allocated to the WLA and LA categories for each source.

Table 4.0.1 Partition of loads between the WLA and LA categories for each source.

Source WLA category LA category
Pets 26% 74%
Other Sources 26% 74%
Sanitary Sewers 0% 100%
SSOs 0% 100%
Septic Systems 0% 100%
Waterfowl 0% 100%
Cone Mills WWTP 100% 0%
Illicit Discharges 100% 0%

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The underlying basis of a TMDL calculation is achieving a defined water quality target
which represents a desired future condition of the waterbody. The desired condition for
North Buffalo Creek is to have a stream which can be safely used for secondary
recreation (as defined by DENR for Class C waters), specifically with respect to risks
posed by human pathogens. In other words, users of the resource should expect a
relatively low risk of contracting water borne diseases from bodily contact with the
stream.

In most cases this target is expressed in a TMDL as an interpretation of the water quality
standard for the pollutant of interest. NC’s fecal coliform standard for Class C waters,
which applies to North Buffalo Creek, is as follows (DENR, 2003):

Fecal coliforms shall not exceed a geometric mean of 200/100ml (MF count)
based upon at least five consecutive samples examined during any 30 day
period, nor exceed 400/100ml in more than 20 percent of the samples
examined during such period; violations of the fecal coliform standard are
expected during rainfall events and, in some cases, this violation is expected
to be caused by uncontrollable nonpoint source pollution; all coliform
concentrations are to be analyzed using the membrane filter technique unless
high turbidity or other adverse conditions necessitate the tube dilution
method; in case of controversy over results, the MPN 5-tube dilution
technique shall be used as the reference method.
Final Report North Buffalo Creek Fecal Coliform TMDL 4.0 Total Maximum Daily Load
48

NC’s fecal coliform standard includes both numeric and narrative components. The
numeric component defines threshold concentrations which should not be exceeded
during a 30 day period. The narrative component suggests that these thresholds may not
be achievable during rainfall events due to uncontrollable nonpoint sources. The
application of NC’s fecal coliform standard within a TMDL framework is subject to a
variety of interpretations in large measure because of this narrative component.

For this TMDL two water quality targets are defined:

one target for dry weather conditions;

and another for all weather conditions, i.e. reflective of both wet and dry
weather periods.

From a management and implementation perspective, having two targets makes sense for
several reasons. First, the period of highest recreational use in North Buffalo Creek is
during warm dry weather conditions. Naturally, this period should be a focus for
implementation with the aid of a TMDL analysis. Second, dry weather sources of fecal
coliform are often associated with human sources, such as illicit discharges and
exfiltrating sanitary sewers. Human sources of fecal coliform tend to represent a higher
disease risk than other sources (CWP, 1999). In addition, dry weather sources tend to be
more technically feasible to control (although not necessarily less expensive to control).
Thus, from an implementation perspective, achieving the dry weather target should be
pursued first.

The dry weather water quality target is a logical management stepping stone towards the
second objective of controlling stormwater driven sources. A second target, reflective of
both wet and dry weather conditions, has been defined as the ultimate goal to pursue.
This target may be very difficult to achieve within an urban environment due to the
multitude and diversity of nonpoint sources - as the narrative portion of the standard
suggests. However, the type of active ongoing stormwater management necessary to
make progress towards meeting this target has widespread advantages for restoring and
protecting the water resource.

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The dry weather TMDL target is defined as a geometric mean not to exceed 200/100mL
based on samples collected at least 72 hours after the last measurable rainfall event over
the course of any 30 day period. In addition, no more than 20% of these samples over the
30 day period are to exceed 400/100mL. Note that a minimum sample number is not
specified as this can not always be guaranteed in the event of an unusually rainy period.
For the TMDL calculation model predictions for days following a 72 hour dry period will
be used.

Final Report North Buffalo Creek Fecal Coliform TMDL 4.0 Total Maximum Daily Load
49

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The all conditions TMDL target is defined as a geometric mean not to exceed 200/100mL
based on 5 or more samples collected over the course of any 30 day period. No more
than 20% of these samples over the 30 day period are to exceed 400/100mL. For the
TMDL calculation all 30 daily model predictions are used. For compliance monitoring
purposes, the 5 or more samples within a 30 day period should not intentionally be
disproportionately reflective of wet or dry conditions.

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The TMDL compliance point is the location along North Buffalo Creek at which the
TMDL calculation will be made. The compliance point also represents the location were
long-term monitoring will be conducted to gage progress towards achieving the two
water quality targets defined above.

North Buffalo Creek at Summit Avenue has been designated as the TMDL compliance
point. Summit Avenue represents the safest, readily accessible, public access point at the
downstream end of the impaired reach as designated in NC’s 2002 Integrated 305(b) and
303(d) List.

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According to federal rules a margin of safety must be included in all TMDLs to provide a
measure of assurance that the impaired waterbody will meet water quality targets once
load reductions are realized. The MOS is intended to offset model uncertainty about the
relationship between pollutant loads and receiving water quality. There is uncertainty
associated with all modeling endeavors since computer models do not perfectly simulate
the complexities of natural systems. Factors such as field and laboratory measurement
error, lack of source assessment information - particularly associated with estimating time
variable loads from unmonitored sources, model error, and gaps in our scientific
knowledge, all contribute to model uncertainty. Unfortunately, most mechanistic models,
including WinHSPF, do not include formal statistical procedures for estimating model
uncertainty. Hence, the choice of a MOS is somewhat arbitrary, but made in good faith
using best professional judgment.

In TMDLs the MOS can be implicit through the use of conservative modeling
assumptions and analytical techniques; or explicit by reserving a portion of the loading
capacity; or a combination of both methods. For this TMDL both an explicit and implicit
MOS was incorporated. An explicit MOS is achieved through the use of water quality
targets based on 180 counts/100mL instead of 200/100mL. In addition, an implicit MOS
is included through the use of conservative modeling techniques, such as assuming that
selected sources contribute loads on a continuous basis, when in reality they probably do
Final Report North Buffalo Creek Fecal Coliform TMDL 4.0 Total Maximum Daily Load
50
Note that the spike in predicted fecal coliform concentration which occurred
in February 2000 was associated with an SSO.
not (see Section 4.1.3 for additional discussion). Therefore, model results should be
carefully interpreted in light of the model limitations and prediction uncertainty.


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Federal rules require consideration of season variation in watershed conditions and
pollutant loads during development of the TMDL. Through the use of a dynamic
continuous simulation model over a 3 year period (August 1998 – August 2001) seasonal
variations have been incorporated into the TMDL calculation.

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Using the calibrated model continuous daily average water quality conditions can be
analyzed. The model predictions are used to develop insights into the relative
contributions of the various sources under different weather conditions. In addition,
existing loads can be estimated and the deviation from the allowable load can be
quantified. With this information at hand, management decisions can be made as to how
the allowable load should be allocated to meet the two water quality targets.

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Figures 4.4.1.1 and 4.4.1.2 illustrate predicted existing fecal coliform concentrations in
North Buffalo Creek at Summit Avenue displayed using arithmetic and log scales,
respectively. Figure 4.4.1.3 illustrates the rolling 30-day geometric mean of predicted
fecal coliform concentrations at Summit Avenue under existing conditions. Note from
Figure 4.4.1.3 that the predicted 30-day geometric mean is consistently above 200/100mL
throughout the simulation period.

Figure 4.4.1.1 Predicted fecal coliform concentrations at Summit Avenue under existing
conditions (arithmetic scale).
Final Report North Buffalo Creek Fecal Coliform TMDL 4.0 Total Maximum Daily Load
51
10
100
1,000
10,000
Aug-98 Nov-98 Feb-99 May-99 Aug-99 Nov-99 Feb-00 May-00 Aug-00 Nov-00 Feb-01 May-01
200/100mL
400/100mL
Predicted Existing Conditions
FC Conc. #/100mL –
30 day geomean
Model Simulation Period

Figure 4.4.1.2 Predicted fecal coliform concentrations at Summit Avenue under existing
conditions (log base 10 scale).

Figure 4.4.1.3 Predicted rolling 30-day geometric mean fecal coliform concentration at
Summit Avenue under existing conditions.

Final Report North Buffalo Creek Fecal Coliform TMDL 4.0 Total Maximum Daily Load
52

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The objective of the dry weather assessment was to evaluate instream conditions during a
period when the effects of fecal coliform loads from surface runoff are minimized. To
assess instream water quality under dry weather conditions a list of dates was complied
which represent days in which 72 or more hours had elapsed without any measurable
rainfall (refer to Appendix 2 for the list of dry weather days). Precipitation data collected
at the USGS Church Street rain gage, centrally located within the TMDL subwatersheds,
was used as the source for rainfall measurements. In this report these dates are referred
to as dry weather days. This definition approximates the actual criteria used by many NC
local governments for identifying when conditions are appropriate for dry weather
instream sampling.

Within the model simulation period predicted daily fecal coliform concentrations for dry
weather days were compiled. A rolling geometric mean of all predicted dry weather day
fecal coliform concentrations within a 30 consecutive day period was calculated (Figure
4.4.1.4). Note from Figure 4.4.1.4 that the 30 day geometric means are significantly
lower when the effect of stormwater driven loads are minimized. However, geometric
means are still consistently above the 200/100mL water quality target.

Figure 4.4.1.4 Predicted rolling 30-day geometric mean fecal coliform concentration at
Summit Avenue under existing dry weather conditions.

10
100
1,000
Aug-98 Nov-98 Feb-99 May-99 Aug-99 Nov-99 Feb-00 May-00 Aug-00 Nov-00 Feb-01 May-01
Model Simulation Period
FC Conc. (#/100mL) - 30 day geomean
Predicted Existing Condition
200/100mL
400/100mL
Final Report North Buffalo Creek Fecal Coliform TMDL 4.0 Total Maximum Daily Load
53
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The data presented in Section 4.4 above, shows that geometric mean fecal coliform
concentrations are consistently higher when rainfall runoff is factored into the analysis, as
compared to dry weather only conditions. Stormwater driven nonpoint sources are
widely recognized in most fecal coliform TMDLs as being significant contributors of
watershed bacterial loads. The findings from this analysis appear to be consistent with a
situation where stormwater-driven nonpoint sources are one of the major causes of water
quality impairment.

Using the calibrated model an analysis was conducted to estimate the relative percentage
of delivered load to Summit Avenue from each of the source categories over the full
simulation period. The delivered load is that portion of the total load generated in the
watershed and transported downstream to Summit Avenue. Hence, the delivered load
reflects the various bacterial die-off processes simulated in the model. Figure 4.5.1
illustrates the relative load contributions from each source.

Figure 4.5.1 Percentage of delivered load to Summit Avenue from each source category
over the full simulation period.
* When interpreting this pie chart it is important to keep in mind that Other Sources represent the load
which could not reasonably be accounted for in the source assessment using the best available data.
The Other Sources category could include for instance loads from unknown wildlife populations.
However, contributions from Other Sources could also reflect an underestimation of the loads from one or more of the identified sources.

Note that pets (dogs and cats) are estimated to account for the largest percentage of
delivered load over the full simulation period - which includes both wet and dry weather
conditions. Other Sources are estimated to account for approximately one third of the
delivered load. It is important to keep in mind that Other Sources represent a category
which might include unknown wildlife populations or other unidentified source types.
However, it is also reasonable to assume that loads from Other Sources could potentially
include contributions which were underestimated from one or more of the identified

















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Final Report North Buffalo Creek Fecal Coliform TMDL 4.0 Total Maximum Daily Load
54
source types. In other words, it is possible that the load from pets, for instance, could be
greater than what is reflected in Figure 4.5.1.

From Figure 4.5.1 it is clear that stormwater-driven sources have to be a focus during
allocation. However from Figure 4.4.1.4, which illustrates that geometric mean
concentrations are also elevated during dry weather conditions, it is evident that reducing
stormwater-driven loads alone will not result in achieving the water quality target.
Hence, a balanced allocation incorporating both stormwater and non-stormwater
driven sources is needed to meet the all conditions water quality target.

To calculate the TMDL, load reductions were taken from the calibrated model until all of
the 30 day geometric means were below the target threshold of 180/100mL (which
includes the explicit margin of safety). In addition, the model output was assessed to
ensure that no more than 6 (20%) of the daily fecal coliform predictions were greater than
400/100mL, in accordance with the all conditions water quality target. Figure 4.5.2
illustrates the predicted rolling 30 day geometric mean fecal coliform concentration at
Summit Avenue after load reductions were applied to the calibrated model. Table 4.5.1
summarizes predicted gross loads from each source before and after modeled reductions
are employed.

Figure 4.5.2 Predicted geometric mean fecal coliform concentration at Summit Avenue
before and after load reductions were applied to the calibrated model.

10
100
1000
10000
Aug-98 Nov-98 Feb-99 May-99 Aug-99 Nov-99 Feb-00 May-00 Aug-00 Nov-00 Feb-01 May-01
Target 180/100mL
Existing Conditions
TMDL Allocation
FC Conc. #/100mL –
30 day geometric mean
Simulation Period
Final Report North Buffalo Creek Fecal Coliform TMDL 4.0 Total Maximum Daily Load
55

Table 4.5.1 Predicted loads from each source during the all weather conditions water
quality target critical period (11/9/98 – 12/8/98).

1 Failing septic systems are estimated to be a minor contributor of fecal coliform loads to the watershed and
technically a large reduction is not needed to achieve the target. However, since failing septic systems are a
controllable source, and since human sources of fecal coliforms are generally recognized as representing a greater disease risk, a large reduction was applied. 2 Due to the practical difficulties of controlling waterfowl populations, no reduction from this source was applied. 3 Cone Mills WWTP no longer discharges directly to North Buffalo Creek as of the summer of 2001.

For the TMDL calculation the critical 30 day period was identified as 11/9/98 – 12/8/98.
This period corresponds to the 30 day period with the highest geometric mean fecal
coliform concentration after load reductions were taken. It is interesting to note from
Figure 4.5.2 that the critical period is not the same as the period of highest geometric
mean concentrations under existing conditions.

This is due in part to the fact that the summer and fall of 1998 was an exceptionally dry
period. In the three months (August, September, and October 1998) leading up the
critical period, the cumulative rainfall total was 6.07 inches as measured at the Church
Street rain gage. This compares to the long term (68 year) average rainfall total of 10.93
inches for those same three months as measured at the airport (PTIA). Hence, for the
three months leading up to the critical period rainfall was approximately 4.9 inches below
normal.

Rainfall during the critical period totaled 2.01 inches. This compares to a long term
average rainfall for the month of November of 2.82 inches. The notable dry spell
preceding the critical period allowed land-based fecal coliform loads to buildup across
the watershed. Although rainfall during the critical period was somewhat below average
also, there was sufficient rain to transport these loads into the stream. To compound the
problem, low stream flows during the critical period minimized the beneficial effects of
dilution, so direct loads to the stream from waterfowl, exfiltrating sanitary sewers, etc,
also contributed significantly to the elevated bacterial concentrations.

Source
Category Source
FC Load Under
Existing
Conditions
(#/30 days)
FC Load After
Reduction
(#/30 days)
WLA & LA Pets 1.42E+13 4.23E+11
WLA & LA Other Sources 8.48E+12 2.53E+11
LA Sanitary Sewers 1.01E+12 1.61E+11
LA SSOs 1.50E+10 7.70E+09
LA Septic Systems 1 9.57E+09 5.55E+08
LA Waterfowl 2 5.78E+11 No reduction
WLA Cone Mills WWTP 3 3.90E+11 No longer
discharging
WLA Illicit Discharges 2.42E+11 9.67E+10
Final Report North Buffalo Creek Fecal Coliform TMDL 4.0 Total Maximum Daily Load
56
The same load reductions applied during wetter conditions, e.g. July 1999, have a larger
affect on reducing geometric mean fecal coliform concentrations, as shown in Figure
4.5.2. During July 1999, for example, rainfall totaled 7.12 inches as compared to a long
term average for the month of July of 4.5 inches. The significant amount of runoff which
occurred during July 1999 contributed to one of the highest predicted geometric mean
fecal coliform concentrations within the simulation period. However, mean stream flow
for July 1999 was approximately double the mean flow during the TMDL critical period
(5.6 cfs vs. 2.8 cfs, respectively as measured at the Church St USGS gage). The
additional instream dilution available during July 1999, as compared to that in November
1998, is part of the reason why load reductions have a larger predicted effect during
wetter conditions.

Table 4.5.2 specifies the percent reductions needed from the major allocation
categories to meet the TMDL requirements associated with the all weather
conditions water quality target. Individual sources (i.e. pets, waterfowl, etc.) have been
grouped into categories to facilitate the distribution of responsibility for implementation.
For example, the MS4 allocation category represents that portion of the fecal coliform
load which is to be addressed through implementation strategies managed as part of the
City of Greensboro’s NPDES stormwater permit. Implementation of load reduction
measures associated with the Nonpoint Source (NPS) allocation category will be
addressed through other local government programs. For the sake of completeness, the
Cone Mills WWTP is presented as an individual allocation category, since
implementation is specifically associated with a NPDES wastewater discharge permit.
However, since this facility was no longer discharging by the end of the TMDL
simulation period, a TMDL load reduction is not applicable (N/A).

Table 4.5.2 Percent load reductions necessary to meet TMDL requirements associated
with the all weather conditions water quality target.

TMDL Allocation Category TMDL % Reduction
MS4 1 96%
Nonpoint Sources 2 93%
Cone Mills WWTP 3 N/A
1 MS4 = Municipal Separate Storm Sewer System. This allocation category includes that portion of the load from pets, Other Sources, and the full load from illicit discharges, which are transported to the receiving stream via the NPDES permitted municipal stormwater conveyance system. 2 The nonpoint source TMDL allocation category includes that portion of the load from pets, Other Sources, and
the full loads from exfiltrating sanitary sewers, SSOs, failing septic systems, and waterfowl which are
transported to the receiving stream by means other than the MS4.
3 Since the Cone Mills WWTP is no longer discharging, a load reduction is not applicable for the purposes of this TMDL.

Table 4.5.3 outlines the sum of the WLAs and LAs for the all weather conditions TMDL.
To calculate the sum of the WLAs and LAs, loads for each source (after reductions were
taken as presented in Tables 4.5.1 and 4.5.2) were partitioned between the two TMDL
components as summarized in Table 4.0.1.
Final Report North Buffalo Creek Fecal Coliform TMDL 4.0 Total Maximum Daily Load
57

Table 4.5.3 TMDL components to meet the all weather conditions water quality target.

WLA
(#/30 days)

LA
(#/30 days) MOS TMDL
(#/30 days)
2.73E+11 1.25E+12 Explicit 1 and Implicit 1.52E+12
1 Explicit Margin of Safety (MOS) is equivalent to 10% of the 30 day geometric mean fecal coliform water quality standard.

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Managing fecal coliform loads is a complex and difficult task, especially in urban
watersheds containing a wide variety of potential sources. From a management
perspective in an urban watershed, focusing resources on the control of dry weather loads
should be the first step. Dry weather fecal coliform loads are often associated with
human sources which are generally recognized as representing a greater risk of disease.
In addition, the recreational use of North Buffalo Creek is generally higher during dry
weather periods. These combination of factors warrant development of a dry weather
TMDL to serve as a guide for targeting implementation strategies.

Using the calibrated model, an analysis was conducted to estimate the relative percentage
of delivered load to Summit Avenue from each of the source categories during dry
weather conditions (72 or more hours after a measurable rainfall event). Figure 4.6.1
illustrates the relative delivered load contributions to Summit Avenue from each source.

Figure 4.6.1 Percentage of delivered load to Summit Avenue from each source category
during dry weather conditions occurring over the full model simulation
period.

Note from Figure 4.6.1 that over three quarters of the total delivered dry weather load to
Summit Avenue is from human sources (exfiltrating sanitary sewers and SSOs). The



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Final Report North Buffalo Creek Fecal Coliform TMDL 4.0 Total Maximum Daily Load
58
residual precipitation induced load from sources such as pets and Other Sources is
negligible, which verifies that 72 hours or more hours after a rainfall event is adequate for
defining dry weather conditions.

From Figure 4.6.1 it is clear that reducing the loads from exfiltrating sanitary sewers and
SSOs have to be a focus in order to meet the dry weather water quality target. To
calculate the dry weather TMDL, load reductions were taken from the calibrated model
until the geometric mean of fecal coliform concentrations for dry weather days during
any 30 day period were below the target threshold of 180/100mL. In addition, the model
output was assessed to ensure that no more than 20% of the daily dry weather fecal
coliform concentrations were greater than 400/100mL, in accordance with the dry
weather water quality target. Figure 4.6.2 illustrates the predicted rolling geometric mean
of dry weather fecal coliform concentrations over any 30 day period at Summit Avenue.

Final Report North Buffalo Creek Fecal Coliform TMDL 4.0 Total Maximum Daily Load
59
Figure 4.6.2 Predicted dry weather geometric mean fecal coliform concentration at
Summit Avenue before and after load reductions were applied to the
calibrated model.

Note from Figure 4.6.2 above that the critical period, i.e. the 30 day period preceding the
highest predicted geometric mean concentration, is very similar to the critical period
reflective of all weather conditions. For the dry weather TMDL the critical period was
identified as 11/9/98 – 12/8/98. Recall from the discussion in Section 4.5, the summer
and fall of 1998 was an especially dry period with very low stream flows to provide
dilution of pollutant loads. Table 4.6.1 summarizes predicted gross loads from each
source before and after modeled reductions are employed during dry weather conditions.

10
100
1000
Aug-98 Nov-98 Feb-99 May-99 Aug-99 Nov-99 Feb-00 May-00 Aug-00 Nov-00 Feb-01 May-01 Aug-01
Target
TMDL Allocation
Existing Conditions
FC Conc. #/100mL –
30 day geometric mean
Simulation Period
Final Report North Buffalo Creek Fecal Coliform TMDL 4.0 Total Maximum Daily Load
60

Table 4.6.1 Predicted loads from each source during the dry weather conditions water
quality target critical period (11/9/98 – 12/8/98).
Source
Category Source
Dry Weather FC
Load Under
Existing
Conditions
(#/30 days)
Dry Weather FC
Load After
Reduction
(#/30 days)
WLA & LA Pets 3.76E+09 No reduction 1
WLA & LA Other Sources 1.13E+09 No reduction 1
LA Sanitary Sewers 2.63E+11 9.81E+09
LA SSOs
No SSOs
occurred during
the critical period

LA Septic Systems 5.07E+09 2.40E+08 2
LA Waterfowl 9.67E+10 No reduction
WLA Cone Mills WWTP 6.57E+10 No longer
discharging 3
WLA Illicit Discharges 6.82E+10 1.85E+10
1 No reductions in precipitation driven sources, such as pets and Other Sources, is warranted during dry weather conditions as these sources are negligible contributors. 2 Failing septic systems are estimated to be a minor contributor of fecal coliform loads to the watershed and technically a large reduction is not needed to achieve the target. However, since failing septic systems are a
controllable source, and since human sources of fecal coliforms are generally recognized as representing a
greater disease risk, a large reduction was applied. 3 Cone Mills WWTP no longer discharges directly to North Buffalo Creek as of the summer of 2001.

Table 4.6.2 specifies the percent reductions needed from the major allocation categories
to meet the TMDL requirements associated with the dry weather conditions water quality
target. During dry weather conditions, illicit discharges to the stormwater conveyance
system are the only individual source type which contributes significant fecal coliform
loads via the MS4.

Table 4.6.2 Percent load reductions necessary to meet TMDL requirements associated
with the dry weather conditions water quality target.

TMDL Allocation Category TMDL % Reduction
MS4 1 72%
Nonpoint Sources 2 70%
Cone Mills WWTP 3 N/A
1 MS4 = Municipal Separate Storm Sewer System. This allocation category includes that portion of the load from pets, Other Sources, and the full load from illicit discharges, which are transported to the receiving stream via
the NPDES permitted municipal stormwater conveyance system. During dry weather conditions, illicit
discharges are the only individual source type which contributes significant fecal coliform loads from the MS4.
2 The nonpoint source TMDL allocation category includes that portion of the load from pets, Other Sources, and the full loads from exfiltrating sanitary sewers, SSOs, failing septic systems, and waterfowl which are transported to the receiving stream by means other than the MS4.
3 Since the Cone Mills WWTP is no longer discharging, a load reduction is not applicable for the purposes of this
TMDL.

Final Report North Buffalo Creek Fecal Coliform TMDL 4.0 Total Maximum Daily Load
61

Table 4.6.3 outlines the sum of the WLAs and LAs for the dry weather conditions
TMDL. To calculate the sum of the WLAs and LAs, the loads for each source after
reductions were taken (as presented in Table 4.6.1), and partitioned between the two
categories as summarized in Table 4.0.1.

Table 4.6.3 TMDL components to meet the dry weather conditions water quality target.

WLA
(#/30 days)

LA
(#/30 days) MOS TMDL
(#/30 days)
1.98E+10 1.10E+11 Explicit 1 and Implicit 1.30E+11
1 Explicit Margin of Safety (MOS) is equivalent to 10% of the 30 day geometric mean fecal coliform water quality standard.
Final Report North Buffalo Creek Fecal Coliform TMDL 5.0 Summary and Future Considerations
62

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Observed instream monitoring data in North Buffalo Creek and its tributaries indicate
that fecal coliform concentrations are above acceptable levels during both dry and wet
weather conditions. The sources of fecal coliform in this urban watershed are many and
diverse. In order to make effective, measurable progress at reducing loads, it will be
important to target implementation efforts in a systematic fashion. A key to success will
be to divide implementation strategies into two categories: one which focuses on
addressing dry weather sources, and another which focuses on stormwater driven sources.
To support the development of these strategies, this document includes a TMDL for dry
weather conditions and another TMDL reflective of all weather (both wet and dry)
conditions.

The dry weather source assessment and TMDL suggests that human sources of fecal
coliform, such as exfiltrating sanitary sewer lines and SSOs, are primary contributors.
Achieving measurable reductions in instream fecal coliform concentrations during dry
weather depends in large measure on controlling these sources. Mapping the major
components of the sanitary sewer collection system is an important component of the
implementation strategy. The control of
other sources, such as illicit discharges to
the stormwater conveyance system, may
also be a key to a successful
implementation strategy.

One of the primary benefits of a TMDL
comes from compiling and analyzing data
about sources in the watershed. Although
exfiltrating sanitary sewers are estimated
to be an significant source within the
watershed, an important consideration to
keep in mind is that very little local data
exists to quantify loads from this source.
In this TMDL studies from another NC
local government and best professional
judgment were relied upon to estimate
loads from exfiltrating sewers.
Therefore, successful implementation
must first be proceeded by local studies to further our understanding of this source.

During stormwater runoff conditions, dogs and cats are estimated to be significant
sources. Reducing fecal coliform loads from pets is especially difficult because the most
effective strategies involve changing the behavior of pet owners. Pet waste ordinances
requiring owners to clean up after their pets are often not very effective as a primary
Aging sanitary sewer lines, especially those constructed with short sections (2’) of clay pipe as shown above, have the potential to be significant sources of bacterial
contamination due to leaks at the joints. Mapping the
major components of the sanitary sewer collection
system will be an important foundation to future implementation strategies.
Final Report North Buffalo Creek Fecal Coliform TMDL 5.0 Summary and Future Considerations
63
management strategy. Few local governments have the resources to enforce such an
ordinance. Rather, a community culture must be developed where citizens expect and
demand that pet owners clean up after their animals. This will require a targeted long-
term public education campaign.

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In the spring of 2003 Greensboro’s Department of Water Resources initiated a follow up
study of dry weather fecal coliform sources in the watershed. This study is supported by
aerial infrared imagery taken in March 2003 to aid in the detection of illicit discharges
from the stormwater conveyance system and other sources. A primary goal of this study
is to target specific catchments within the
TMDL area and identify actions to be taken
as part of a comprehensive implementation
strategy.

Greensboro is one of a number of
municipalities providing support for a
Microbial Source Tracking (MST) study
managed by the NC Division of Water
Quality. North Buffalo Creek is one of
several streams statewide being investigated
using MST technologies. While
considerable effort went into the source
assessment for this TMDL, the MST study
may provide additional insight as to the
importance of sources such as wildlife, for
which very little is known.

Public education initiatives aimed at encouraging citizens to use tight fitting trash can
lids, and other proper solid waste disposal practices, can be effective at discouraging
nuisance urban wildlife. However, a balanced wildlife population is an important
component of a healthy ecosystem. Future implementation strategies targeted towards
wildlife populations will need to be carefully considered.

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Greensboro’s Department of Water Resources is currently engaged in a multi-year effort
to develop stormwater masterplans for each of the major watersheds within its
jurisdictions. The objective of each plan is to identify the major water quantity and
quality issues within the watershed and outline structural and nonstructural BMPs to
correct/minimize the identified problems. The South Buffalo Creek watershed
masterplan was completed in 2002, and the draft Horsepen Creek watershed masterplan
was completed in the spring of 2003. The City’s Horsepen Creek planning process
Wildlife, such as the raccoon who left this track, were
grouped and accounted for in this TMDL with other
unknown sources for which no field data was
available. The MST study currently underway may provide some insight as to the importance of wildlife as a source of fecal coliform contamination in North
Buffalo Creek.
Final Report North Buffalo Creek Fecal Coliform TMDL 5.0 Summary and Future Considerations
64
included significant support for, and coordination with DWQ’s Watershed Assessment
and Restoration Project (WARP), to add value to both water quality improvement
initiatives. Such multi-agency cooperative efforts are essential for solving complex urban
water quality challenges. The City of Greensboro will continue its tradition of supporting
the Division of Water Quality and other organizations dedicated to improving water
quality and restoring impaired uses.

Final Report North Buffalo Creek Fecal Coliform TMDL 6.0 References
65

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))))

Kebede, 2003. Adugna Kebede. Environmental Modeler – NC Division of Water
Quality. Personal communication. Provided effluent data for the Cone Mills WWTP.
March 2003.

Audubon, 2003. National Audubon Society. Data for the period 1991 – 2001 accessible
from: http://www.audubon.org/bird/cbc/.

AVMA, 1997. U.S. Pet Ownership & Demographics Sourcebook. Published by the
American Veterinary Medical Association.

DENR, 2003. NC Department of Environment and Natural Resources. North Carolina
Administrative Code - 15A NCAC 02B .0202 (57) Definition of secondary recreation;
15A NCAC 02B .0211 Fresh surface water quality standards for Class C waters. April 1,
2003. Accessible from: http://h2o.enr.state.nc.us/admin/rules/

DWQ, 1985. NC Division of Water Quality. North Carolina Schedule of Classifications.
North Buffalo Creek classification data listed as 8/1/85. Accessible from:
http://h2o.enr.state.nc.us/bims/Reports/reports.html

DWQ, 2003. NC Division of Water Quality. North Carolina Water Quality Assessment
and Impaired Waters List (2002 Integrated 305(b) and 303(d) Report). Final February
2003. Accessible from: http://h2o.enr.state.nc.us/tmdl/

DWR, 2002. NC Division of Water Resources. 1999 water withdrawal registration
records accessible from: http://dwr32.ehnr.state.nc.us:81/cgi-
bin/foxweb.exe/c:/foxweb/reg99reg^0048-0003

CWP, 1999. Center for Watershed Protection. April 1999. Microbes and Urban
Watersheds. Watershed Protection Techniques. 3(1): 551-595.

Edwards, 2002. Jay Edwards. Inspector, Guilford County Health Department. Personal
communication. April 2002.

Horsely and Whitten, 1996. Identification and evaluation of nutrient and bacterial
loadings to Maquiot Bay, New Brunswick and Freeport, Maine. Final Report. Casco
Bay Estuary Project, Portland, ME.
Final Report North Buffalo Creek Fecal Coliform TMDL 6.0 References
66

Kroening, 2002. David Kroening. Water Quality Surface Water Systems Analyst –
Mecklenburg County Department of Environmental Protection. Personal
communication. Provided data from Mecklenburg County studies on dry weather flow
from stormwater outfalls and ground water fecal coliform concentrations near sanitary
sewer lines. January 2002.

MCDEP/DWQ, 2002. Fecal Coliform Total Maximum Daily Load for the Irwin,
McAlpine, Little Sugar and Sugar Creek Watersheds, Mecklenburg County. Final
February 2002. Prepared by the Mecklenburg County Department of Environmental
Protection and the NC Division of Water Quality. Accessible from:
http://h2o.enr.state.nc.us/tmdl/TMDL_list.htm#Final_TMDLs

PTCOG, 2003. Identification and Reduction of Fecal Coliform Bacteria Sources for
North Carolina 303(d) Listed Waters in Greensboro and High Point. Report produced by
Carol Patrick with the Piedmont Triad Council of Governments. August 2003.
Accessible from: http://www.ptcog.org/d_water.htm

Roessler, 2002. Chris Roessler. Environmental Modeler. NC Division of Water Quality.
Personal communication. March 2002. Provided electronic spreadsheet of USEPA’s
Fecal Tool and MS Word document of: Fecal Tool User’s Guide. Draft report submitted
to USEPA by Tetra Tech, Inc. 2001 Fairfax, Virginia.

Schueler, T. 1994. The importance of imperviousness. Watershed Protection
Techniques. 1(3): 100-111.

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

USEPA, 2000. U.S. Environmental Protection Agency. BASINS Technical Note 6.
Estimating Hydrology and Hydraulic Parameters for HSPF. Office of Water, Washington
DC. EPA 823-R-00-012. July 2000. Accessible from:
http://www.epa.gov/waterscience/basins/tecnote6.pdf

USEPA, 2000a. U.S. Environmental Protection Agency. 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).

USEPA, 2002. U.S. Environmental Protection Agency. EPA National TMDL Guidance.
Establishing Total Maximum Daily Load (TMDL) Wasteload Allocations (WLAs) for
Storm Water Sources and NPDES Permit Requirements Based on Those WLAs. Robert
H. Wayland, III and James A. Hanlon -- November 22, 2002. Accessible from:
http://www.epa.gov/npdes/pubs/final-wwtmdl.pdf

Final Report North Buffalo Creek Fecal Coliform TMDL 6.0 References
67
USGS, 1994. U.S. Geological Survey. Users Manual for an Expert System (HSPEXP)
for Calibration of the Hydrological Simulation Program—Fortran. By Alan M. Lumb,
Richard B. McCammon, and John L. Kittle, Jr. Water-Resources Investigations Report
94-4168. Accessible from:
ftp://water.usgs.gov/pub/software/surface_water/hspexp/doc/hspexp.pdf

Wilmington, 2002. City of Wilmington Stormwater Services. Hewletts Creek
Restoration Plan for Recreational and Shellfish Waters. November 2002. Accessible
from:
http://www.ci.wilmington.nc.us/pubservices/stormwater/PDF%20files/hewletts_shellfish
_plan_finalprint.pdf
Final Report North Buffalo Creek Fecal Coliform TMDL A-1 Instream Fecal Coliform Monitoring Data
68



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Piedmont Triad Council of Governments Sampling Data
All Stations in North Buffalo Creek

Fecal coliform concentrations - #/100mL (Hours since previous rainfall)
Source: PTCOG, 2003
Date Market St.
(Subwatershed 1)
Elam St.
(Head of subwatershed 3)
Garland Ave.
(subwatershed 4)
Cridland
Ave.
(subwatershed 4)
Church St.
(outlet of subwatershed 4)
6/5/2001 515 (72)
6/11/2001 1,081 (96) 1,182 (96) 800 (96) 786 (96) 891 (96)
6/18/2001 540 (48) 740 (48) 600 (48) 6,000 (48) 365 (48)
6/20/2001 2,400 (96) 840 (96)
7/23/2001 890 (96) 520 (96) 1,140 (96) 211 (96) 1,100 (96)
8/6/2001 493 (72) 510 (72) 1,040 (72) 460 (72) 280 (72)
8/8/2001 1,000 (120) 300 (120) 1,140 (120) 370 (120) 150 (120)
8/17/2001 880 (72) 595 (72) 2,300 (72) 620 (72) 460 (72)
8/23/2001 820 (72) 1,060 (72) 1,220 (72) 840 (72) 500 (72)
9/10/2001 1,230 (120) 550 (120) 585 (120) 483 (120) 200 (120)
9/17/2001 853 (144) 300 (144) 780 (144) 430 (144) 181 (144)
9/18/2001 250 (168) 194 (168) 1,530 (168) 390 (168) 210 (168)
10/2/2001 507 (72) 131 (72) 540 (72) 373 (72) 200 (72)
10/4/2001 690 (72) 445 (72) 730 (72) 195 (72) 220 (72)
10/17/2001 790 (48)
10/30/2001 200 (72) 88 (72) 250 (72) 105 (72) 200 (72)
11/1/2001 350 (48)
12/5/2001 600 (48)
12/20/2001 330 (48)
5/8/2002 947 (72) 800 (72)
7/18/2002 800 (48) 800 (48)
10/22/2002 3,300 (72) 2,200 (72) 3,400 (72) 3,400 (72) 3,700 (24)
10/24/2002 760 (96) 460 (96) 3,900 (96) 700 (96) 720 (72)
10/30/2002 2,500 (96) 5,000 (96) 3,600 (96) 5,656 (96) 5,500 (96)
11/7/2002 1,267 (48) 860 (48) 2,467 (48) 4,900 (48) 460 (48)
11/13/2002 960 (24) 2,300 (24) 2,600 (24) 3,550 (24) 3,867 (24)
11/18/2002 600 (36) 2,350 (36) 2,600 (36) 2,350 (36) 2,950 (36)
11/19/2002 580 (48) 600 (48) 2,150 (48) 1,530 (48) 2,300 (na)
12/16/2002 968 (48) 968 (48)
Final Report North Buffalo Creek Fecal Coliform TMDL A-1 Instream Fecal Coliform Monitoring Data
69
PTCOG Sampling Data - continued
Date Market St.
(Subwatershed 1)
Elam St.
(Head of subwatershed 3)
Garland Ave.
(subwatershed 4)
Cridland
Ave.
(subwatershed 4)
Church St.
(outlet of subwatershed 4)
12/18/2002 1,180 (na)
12/19/2002 400 (na)
1/30/2003 1,060 (na)
2/24/2003 440 (24)
Shading indicates data collected outside the model simulation period. These data
are presented for information purposes, but were not used for model calibration.

Final Report North Buffalo Creek Fecal Coliform TMDL A-1 Instream Fecal Coliform Monitoring Data
70

Greensboro Stormwater Management Division Sampling Data
All Stations Except 16th St. in North Buffalo Creek

Fecal coliform concentrations - #/100mL
Source: Greensboro Stormwater Management Division
Date Arboretum
(subwatershed 1)
Aycock St.
(outlet of subwatershed 3)
Church St.
(outlet of subwatershed 4)
16th St.
(subwatershed 7)
7/9/1996 4,200
8/13/1996 8,900
9/10/1996 4,500
10/9/1996 2,200
11/12/1996 520
12/10/1996 560
1/13/1997 210
2/11/1997 140
3/11/1997 220
4/8/1997 460
5/13/1997 1,200
6/10/1997 790
7/8/1997 10,000
8/12/1997 1,400
9/9/1997 1,900
10/14/1997 750
11/14/1997 240
12/10/1997 19,000
1/13/1998 2,000
2/10/1998 260
3/10/1998 500
4/14/1998 5,800
5/12/1998 1,200
6/9/1998 1,400
7/14/1998 1,200
10/12/1998 3,700
1/13/1999 270
4/14/1999 770
7/22/1999 17,000 9,100 4,500
8/25/1999 29,000
9/20/1999 760 1,200 1,000
11/10/1999 450 790 580
12/10/1999 6,400
2/17/2000 74 2 98
Final Report North Buffalo Creek Fecal Coliform TMDL A-1 Instream Fecal Coliform Monitoring Data
71
Greensboro Sampling Data - continued
Date Arboretum
(subwatershed 1)
Aycock St.
(outlet of subwatershed 3)
Church St.
(outlet of subwatershed 4)
16th St.
(subwatershed 7)
2/18/2000 2,600
3/15/2000 400 480 54
4/13/2000 5,700
5/10/2000 760 810 570
7/11/2000 4,800
7/12/2000 6,000 2,300
8/18/2000 8,300
9/12/2000 970 580 2,100
11/9/2000 8,400
11/13/2000 380 1,100 590
1/16/2001 37 72 40
1/30/2001 150
3/27/2001 72 58 150
4/24/2001 5,200
5/1/2001 390 360 460
7/17/2001 4,200 330 580
7/25/2001 6,000
9/18/2001 8 5 2

Shading indicates data collected outside the model simulation period.
These data are presented for information purposes, but were not used
for model calibration.

Final Report North Buffalo Creek Fecal Coliform TMDL A-1 Instream Fecal Coliform Monitoring Data
72

Cone Mills WWTP – Instream fecal coliform sampling data from North Buffalo Creek at
Summit Avenue.
Date
Summit Ave.
Fecal coliform
(#/100mL)
8/3/1998 870
8/4/1998 10
8/5/1998 5
8/6/1998 5
8/7/1998 17
8/10/1998 653
8/11/1998 1,210
8/12/1998 1,900
8/13/1998 720
8/14/1998 328
8/17/1998 290
8/18/1998 570
8/19/1998 210
8/20/1998 2,000
8/21/1998 270
8/24/1998 810
8/25/1998 280
8/26/1998 750
8/27/1998 790
8/28/1998 270
9/1/1998 252
9/2/1998 650
9/3/1998 613
9/4/1998 143
9/8/1998 430
9/9/1998 77
9/10/1998 770
9/11/1998 2,000
9/14/1998 860
9/15/1998 810
9/16/1998 1,210
9/17/1998 350
9/18/1998 2,300
9/21/1998 152
9/22/1998 860
9/23/1998 3,700
9/24/1998 330
Date
Summit Ave.
Fecal coliform
(#/100mL)
9/25/1998 10
9/28/1998 5
9/29/1998 5
9/30/1998 213
10/1/1998 64
10/2/1998 82
10/5/1998 415
10/6/1998 370
10/7/1998 290
10/8/1998 4,700
10/9/1998 870
10/12/1998 460
10/13/1998 623
10/14/1998 407
10/15/1998 113
10/16/1998 5
10/19/1998 10
10/20/1998 5
10/21/1998 5
10/22/1998 5
10/23/1998 109
10/26/1998 260
10/27/1998 5
10/28/1998 2
10/29/1998 28
10/30/1998 363
11/2/1998 214
11/3/1998 2,750
11/4/1998 114
11/5/1998 135
11/6/1998 84
11/9/1998 10
11/10/1998 141
11/11/1998 2,800
11/12/1998 3,400
11/13/1998 730
11/16/1998 4,600
Date
Summit Ave.
Fecal coliform
(#/100mL)
11/17/1998 740
11/18/1998 840
11/19/1998 2,100
11/20/1998 3,000
11/23/1998 120
11/24/1998 570
11/25/1998 90
11/27/1998 423
11/30/1998 10
12/1/1998 53
12/2/1998 145
12/3/1998 82
12/4/1998 212
12/7/1998 76
12/8/1998 537
12/9/1998 4,900
12/10/1998 1,280
12/11/1998 1,170
12/14/1998 1,090
12/15/1998 930
12/16/1998 447
12/17/1998 195
12/18/1998 165
12/21/1998 119
12/22/1998 1,000
12/23/1998 3,000
12/29/1998 667
12/30/1998 1,010
12/31/1998 5,600
1/4/1999 970
1/5/1999 400
1/6/1999 1,070
1/7/1999 5,000
1/8/1999 950
1/11/1999 790
1/12/1999 5,100
1/13/1999 2,200
Final Report North Buffalo Creek Fecal Coliform TMDL A-1 Instream Fecal Coliform Monitoring Data
73
Date Summit Ave. Fecal coliform
(#/100mL)
1/14/1999 1,200
1/15/1999 1,800
1/18/1999 4,200
1/19/1999 420
1/20/1999 20
1/21/1999 1,180
1/22/1999 1,100
1/25/1999 640
1/26/1999 370
1/27/1999 660
1/28/1999 377
1/29/1999 1,000
2/1/1999 5,500
2/2/1999 1,300
2/3/1999 280
2/4/1999 10
2/5/1999 42
2/8/1999 114
2/9/1999 10
2/10/1999 4
2/11/1999 2
2/12/1999 5
2/15/1999 240
2/16/1999 19
2/17/1999 54
2/18/1999 3,800
2/22/1999 3,000
3/3/1999 76
3/10/1999 2,900
3/17/1999 110
3/24/1999 820
4/1/1999 5,630
4/7/1999 97
4/14/1999 175
4/21/1999 198
4/28/1999 9,200
5/5/1999 475
5/12/1999 333
5/19/1999 980
Date Summit Ave. Fecal coliform
(#/100mL)
5/26/1999 6,300
6/1/1999 213
6/2/1999 690
6/3/1999 3,300
6/7/1999 373
6/9/1999 362
6/11/1999 6,000
6/14/1999 6,100
6/16/1999 2,200
6/17/1999 5,900
6/21/1999 780
6/23/1999 470
6/25/1999 720
6/28/1999 1,160
6/29/1999 2,200
6/30/1999 665
7/6/1999 293
7/7/1999 620
7/8/1999 2,300
7/12/1999 1,440
7/13/1999 6,030
7/14/1999 1,340
7/19/1999 2,200
7/20/1999 6,500
7/21/1999 4,000
7/27/1999 740
7/28/1999 135
7/29/1999 6,600
8/3/1999 89
8/4/1999 6
8/5/1999 235
8/9/1999 645
8/10/1999 22
8/12/1999 83
8/17/1999 220
8/18/1999 69
8/19/1999 176
8/24/1999 430
8/25/1999 1,250
Date Summit Ave. Fecal coliform
(#/100mL)
8/26/1999 185
8/31/1999 81
9/1/1999 105
9/3/1999 145
9/8/1999 114
9/9/1999 330
9/13/1999 348
9/14/1999 213
9/16/1999 10,000
9/20/1999 555
9/21/1999 378
9/22/1999 1,180
9/28/1999 7,900
9/29/1999 286
9/30/1999 280
10/8/1999 50
10/14/1999 470
10/22/1999 255
10/27/1999 570
11/3/1999 1,220
11/10/1999 22
11/17/1999 33
11/23/1999 83
12/1/1999 195
12/8/1999 1,100
12/15/1999 1,140
12/21/1999 278
12/29/1999 3,400
1/4/2000 81
1/12/2000 88
1/19/2000 455
1/28/2000 18
2/2/2000 198
2/10/2000 135
2/16/2000 323
2/24/2000 278
3/2/2000 640
3/9/2000 78
3/16/2000 1,120
Final Report North Buffalo Creek Fecal Coliform TMDL A-1 Instream Fecal Coliform Monitoring Data
74
Date Summit Ave. Fecal coliform
(#/100mL)
3/23/2000 330
3/29/2000 285
4/6/2000 205
4/12/2000 120
4/20/2000 67
4/27/2000 155
5/3/2000 320
5/10/2000 170
5/17/2000 5,700
5/24/2000 495
6/1/2000 535
6/2/2000 860
6/6/2000 3,100
6/7/2000 800
6/8/2000 1,100
6/13/2000 395
6/14/2000 575
6/15/2000 5,600
6/20/2000 1,660
6/21/2000 5,350
6/22/2000 1,020
6/27/2000 685
6/28/2000 210
6/29/2000 9,200
7/5/2000 3,950
7/6/2000 5,500
7/7/2000 11,800
7/11/2000 12,000
7/12/2000 8,200
7/13/2000 10,000
7/17/2000 1,630
7/18/2000 310
7/19/2000 250
7/20/2000 280
7/25/2000 2,900
7/26/2000 700
7/27/2000 3,400
8/1/2000 4,650
8/2/2000 11,600
Date Summit Ave. Fecal coliform
(#/100mL)
8/3/2000 5,030
8/9/2000 780
8/10/2000 1,780
8/11/2000 12,400
8/14/2000 920
8/15/2000 210
8/16/2000 210
8/22/2000 198
8/23/2000 188
8/24/2000 710
8/29/2000 2,800
8/30/2000 3,700
8/31/2000 2,300
9/6/2000 860
9/7/2000 460
9/8/2000 880
9/12/2000 6,000
9/13/2000 400
9/14/2000 940
9/19/2000 4,200
9/20/2000 1,060
9/21/2000 230
9/25/2000 952
9/26/2000 20
9/27/2000 31
10/5/2000 430
10/13/2000 230
10/18/2000 6,600
10/25/2000 880
11/1/2000 545
11/9/2000 535
11/15/2000 4,600
11/24/2000 1,320

Final Report North Buffalo Creek Fecal Coliform TMDL A-2 Dry Weather Dates
75













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Dry weather dates used for calculations associated with the dry weather TMDL
)00 --)-00 --) 0 0 --)0)0 ---0 0 ---,00 --- +00 --- 00+++
)0*0 --)-0,0 --) 00 --)0-0 ---0 0 ---,00 --- +00 --- 00+++
)00 --)-0)0 --) 00 --)0 +0 ---0 0 ---,0 ,0 --- +0,0 --- 0,0+++
)00 --)-0-0 --) 0*0 --)0 0 ---0 ,0 ---,0 )0 --- +0)0 --- 0)0+++
)0 0 --) +00 --) 0-0 --)0 0 ---0 )0 ---,0 -0 --- 0 0 --- 0 0+++
)0 *0 --) +0 0 --) 0+0 --)00 ---0 -0 ---)0 0 --- 00 --- 0 ,0+++
)0 0 --) +0 0 --) 0 0 --)00 ---0+0 ---)00 --- 00 --- 0 )0+++
)0+0 --) +0 0 --) 00 --)0*0 ---0 0 ---)00 --- 0,0 ---00+++
)0 0 --) +0 *0 --) 00 --)00 ---00 ---)0*0 --- 0)0 ---0,0+++
)00 --) +0 0 --) 0*0 --)0 0 ---00 ---)00 --- 0-0 ---0)0+++
)00 --) +0 0 --) 00 --)0 -0 ---0*0 ---)00 --- 0 +0 ---0-0+++
)0*0 --) +0 ,0 --) 00 --)0+0 ---00 ---)0,0 --- 0 0 ---0 +0+++
)00 --) +0 )0 --) 0,0 --)0)0 ---0-0 ---)0 0 --- 0 0 ---0 0+++
)00 --) +0 -0 --) 00 --)0-0 ---0+0 ---)0 0 --- 0 0 ---00+++
)0,0 --) +0+0 --) 0 0 ---0+0 ---0 0 ---)0 ,0 --- 0 *0 ---00+++
)0)0 --) +0 0 --) 00 ---0 0 ---0 0 ---)0 )0 --- 0 0 ---0*0+++
)0-0 --) +00 --) 0,0 ---*0*0 ---00 ---)0 -0 --- 0 -0 ---00+++
-00 --) +00 --) 0 0 ---*0)0 ---00 ---)00 --- 0+0 ---00+++
-0,0 --) +0*0 --) 0 0 ---*0 -0 ---0*0 ---)0+0 --- 00 ---0 0+++
-0 0 --) +00 --) 0 *0 ---*0+0 ---00 ---)0 0 --- 0*0 ---00+++
-0 0 --) +00 --) 0 0 ---*0 0 ---00 ----0 0 --- 0-0 ---00+++
-0 0 --) +0,0 --) 00 ---*00 ---0,0 ----00 --- 0 ,0 ---0*0+++
-0 *0 --) +0)0 --) 0,0 ---*00 ---0)0 ----00 --- 0 )0 ---00+++
-0 0 --) +0-0 --) 0)0 ---*0*0 ---0-0 ----0 0 --- 00 ---00+++
-0 0 --) 00 --) 0-0 ---*00 ---0 +0 ----0 *0 --- 0,0 ---0,0+++
-0 ,0 --) 0,0 --) 0+0 ---00 ---0 0 ----0 -0 --- 0)0 ---0)0+++
-0 )0 --) 0)0 --) 0 0 ---0*0 ---0 0 ----0+0 --- 0-0 ---0-0+++
-0 -0 --) 0-0 --)00 ---0)0 ---0 -0 ----00 --- 0+0 ---0 +0+++
-0+0 --) 0 -0 --)00 ---0-0 ---0-0 ----00 --- 0 0 ---0 *0+++
-00 --) 0+0 --)0,0 ---0 +0 ---,0*0 --- +00 --- 0 0+++0 0+++
Final Report North Buffalo Creek Fecal Coliform TMDL A-2 Dry Weather Dates
76

Dry weather dates - continued

0*0+++0 0+++-0+0+++ +0+0+++ 00+++0,0++ 0 0++ 
*0,0+++0 0+++ +0 0+++ +0 0+++ 0*0+++0)0++ 00++ 
*0 0+++00+++ +00+++ 0 0+++ 00+++0-0++ 00++ 
*0 0+++0*0+++ +00+++ 00+++ 00+++0)0++ 0*0++ 
*0+0+++,00+++ +0*0+++ 00+++ 0,0+++0 0++ 00++ 
*0 0+++,00+++ +00+++ 0*0+++ 0)0+++00++ 0-0++ 
*00+++,0 +0+++ +00+++ 00+++ 0-0+++0)0++ 0 +0++ 
*00+++,0 0+++ +0,0+++ 00+++ 0+0+++0-0++ 0 0++ 
*0*0+++,0 ,0+++ +0)0+++ 0 0+++ 0 0+++0 +0++ 0 0++ 
0 0+++,0 )0+++ +0-0+++ 0 0+++ 0 0++ 0 0++ 0 ,0++ 
00+++,0 -0+++ +0 +0+++ 00+++ 00++ 0 -0++ 0 )0++ 
00+++,0+0+++ +0 0+++ 00+++ 00++ 0*0++ 0 -0++ 
0*0+++,0 0+++ +0 0+++ 0*0+++ 0*0++ 00++ 0+0++ 
00+++,00+++ +0 0+++ 0+0+++ 00++ 00++ 0+0++ 
00+++,0-0+++ +0 *0+++ 0 0+++ 00++ 0,0++ ,0,0++ 
0,0+++,0+0+++ +0 0+++ 00+++ 0,0++ 0)0++ ,0 0++ 
0)0+++)0 0+++ +0 0+++ 00+++ 0 0++ *00++ ,0 0++ 
0-0+++)0 ,0+++ +0 ,0+++ 0*0+++ 0 0++ *0,0++ ,0 ,0++ 
0 +0+++)0 0+++ +0 )0+++ 00+++ 00++ *0)0++ ,0 0++ 
0 0+++)00+++ +0 -0+++ 00+++ 0*0++ *0-0++ ,00++ 
0 0+++)00+++ +0+0+++ 0,0+++ 00++ *0 +0++ ,00++ 
0 0+++-0,0+++ +0 0+++ 0)0+++ 00++ *0 0++ 
0 *0+++-0)0+++ +00+++ 0-0+++ 0,0++ *0 0++ 
0 0+++-0-0+++ +00+++ 0 +0+++ 0)0++ *0+0++ 
0 0+++-0 +0+++ +0*0+++ 0 0+++ 0-0++ *0 0++ 
0 0+++-0 0+++ +00+++ 0 0+++00++ *00++ 
00+++-0 0+++ +00+++ 0 0+++00++ *00++ 
0-0+++-0 0+++ +0,0+++ 0 *0+++0*0++ *0)0++ 
0 +0+++-0)0+++ +0)0+++ 0 0+++00++ *0-0++ 
0 0+++-0-0+++ +0-0+++ 00+++00++ *0+0++ 

Final Report North Buffalo Creek Fecal Coliform TMDL A-3 Cone Mills WWTP Effluent Data
77



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Cone Mills WWTP effluent data. Flow and fecal coliform concentrations (August 1998 –
June 2001) (Kebede, 2003).

Date
Flow
(mgd)
FC
(#/100mL)
8/1/1998 0.76 1
8/2/1998 0.70 1
8/3/1998 0.75 1
8/4/1998 1.09 1
8/5/1998 1.58 1
8/6/1998 1.33 1
8/7/1998 1.46 9
8/8/1998 1.45 3
8/9/1998 1.27 3
8/10/1998 1.16 1
8/11/1998 1.27 1
8/12/1998 1.63 4
8/13/1998 1.62 1
8/14/1998 1.58 8
8/15/1998 1.11 7
8/16/1998 0.82 6
8/17/1998 1.00 1
8/18/1998 1.08 16
8/19/1998 1.09 1
8/20/1998 1.12 4
8/21/1998 1.00 85
8/22/1998 0.85 27
8/23/1998 0.04 27
8/24/1998 0.76 13
8/25/1998 1.17 8
8/26/1998 1.05 1
8/27/1998 0.84 1
8/28/1998 0.84 27
8/29/1998 0.84 29
8/30/1998 0.54 29
8/31/1998 0.97 78
9/1/1998 0.97 7
9/2/1998 0.90 1
9/3/1998 0.97 1
9/4/1998 0.88 1
9/5/1998 0.80 1
9/6/1998 0.73 1
Date
Flow
(mgd)
FC
(#/100mL)
9/7/1998 0.73 1
9/8/1998 0.89 1
9/9/1998 1.18 1
9/10/1998 1.17 1
9/11/1998 1.14 88
9/12/1998 1.19 37
9/13/1998 1.08 37
9/14/1998 1.13 11
9/15/1998 1.22 48
9/16/1998 1.29 62
9/17/1998 1.33 113
9/18/1998 1.38 98
9/19/1998 1.01 54
9/20/1998 1.01 54
9/21/1998 1.25 4
9/22/1998 1.95 1
9/23/1998 1.20 15
9/24/1998 1.20 1
9/25/1998 1.20 1
9/26/1998 1.20 1
9/27/1998 1.20 1
9/28/1998 0.97 1
9/29/1998 0.97 1
9/30/1998 1.17 1
10/1/1998 0.97 12
10/2/1998 0.91 1
10/3/1998 0.70 24
10/4/1998 0.55 24
10/5/1998 0.91 9
10/6/1998 0.89 76
10/7/1998 1.46 9
10/8/1998 1.45 23
10/9/1998 1.27 22
10/10/1998 1.16 1
10/11/1998 1.27 4
10/12/1998 1.13 4
10/13/1998 0.71 4
Date
Flow
(mgd)
FC
(#/100mL)
10/14/1998 0.73 2
10/15/1998 0.77 2
10/16/1998 0.98 2
10/17/1998 1.06 2
10/18/1998 0.77 2
10/19/1998 0.83 1
10/20/1998 0.97 2
10/21/1998 1.13 1
10/22/1998 1.12 1
10/23/1998 1.10 7
10/24/1998 0.98 3
10/25/1998 0.62 3
10/26/1998 0.71 2
10/27/1998 0.82 1
10/28/1998 0.87 20
10/29/1998 1.47 17
10/30/1998 1.25 58
10/31/1998 0.89 61
11/1/1998 0.54 61
11/2/1998 0.54 12
11/3/1998 0.58 156
11/4/1998 0.67 8
11/5/1998 0.69 1
11/6/1998 0.70 1
11/7/1998 0.46 1
11/8/1998 0.33 1
11/9/1998 0.36 1
11/10/1998 0.69 1
11/11/1998 0.90 10
11/12/1998 0.95 100
11/13/1998 1.02 197
11/14/1998 0.98 152
11/15/1998 0.41 152
11/16/1998 0.84 2
11/17/1998 0.94 311
11/18/1998 1.00 124
11/19/1998 1.12 183
Final Report North Buffalo Creek Fecal Coliform TMDL A-3 Cone Mills WWTP Effluent Data
78
Date
Flow
(mgd)
FC
(#/100mL)
11/20/1998 1.11 101
11/21/1998 0.89 430
11/22/1998 0.44 429
11/23/1998 0.57 1198
11/24/1998 0.94 233
11/25/1998 0.94 96
11/26/1998 0.26 90
11/27/1998 0.33 5
11/28/1998 0.94 40
11/29/1998 0.38 40
11/30/1998 0.70 27
12/1/1998 1.01 87
12/2/1998 1.49 24
12/3/1998 1.49 1
12/4/1998 1.49 125
12/5/1998 1.49 180
12/6/1998 1.49 180
12/7/1998 1.49 359
12/8/1998 1.49 235
12/9/1998 1.33 329
12/10/1998 1.33 214
12/11/1998 1.25 325
12/12/1998 1.12 177
12/13/1998 0.78 176
12/14/1998 0.56 83
12/15/1998 0.88 83
12/16/1998 0.78 54
12/17/1998 0.79 25
12/18/1998 0.67 43
12/19/1998 0.87 78
12/20/1998 0.87 78
12/21/1998 0.60 117
12/22/1998 0.60 125
12/23/1998 0.67 150
12/24/1998 0.72 153
12/25/1998 0.64 153
12/26/1998 0.58 153
12/27/1998 0.65 153
12/28/1998 0.67 153
12/29/1998 0.61 236
12/30/1998 0.62 102
12/31/1998 0.61 116
1/1/1999 0.67 81
1/2/1999 0.76 81
1/3/1999 0.74 81
1/4/1999 0.77 81
1/5/1999 0.96 65
Date
Flow
(mgd)
FC
(#/100mL)
1/6/1999 1.67 42
1/7/1999 1.55 62
1/8/1999 1.61 260
1/9/1999 1.28 278
1/10/1999 1.06 719
1/11/1999 1.06 1139
1/12/1999 1.75 1199
1/13/1999 1.44 4303
1/14/1999 1.82 24
1/15/1999 1.76 2
1/16/1999 1.39 30
1/17/1999 1.25 30
1/18/1999 1.34 2
1/19/1999 1.15 93
1/20/1999 1.34 10
1/21/1999 1.18 66
1/22/1999 0.85 222
1/23/1999 0.78 163
1/24/1999 0.95 162
1/25/1999 0.80 172
1/26/1999 0.79 190
1/27/1999 0.81 274
1/28/1999 1.23 384
1/29/1999 1.10 218
1/30/1999 0.72 151
1/31/1999 0.57 151
2/1/1999 0.55 2
2/2/1999 0.54 2
2/3/1999 0.50 2
2/4/1999 0.45 2
2/5/1999 0.40 1
2/6/1999 0.38 1
2/7/1999 0.45 1
2/8/1999 0.94 2
2/9/1999 1.11 1
2/10/1999 1.15 1
2/11/1999 1.30 1
2/12/1999 1.46 1
2/13/1999 1.00 2
2/14/1999 0.85 2
2/15/1999 0.92 2
2/16/1999 1.05 2
2/17/1999 1.14 2
2/18/1999 1.26 2
2/19/1999 1.41 9
2/20/1999 1.41 4
2/21/1999 1.19 4
Date
Flow
(mgd)
FC
(#/100mL)
2/22/1999 1.12 2
2/23/1999 1.27 2
2/24/1999 1.36 1
2/25/1999 1.43 21
2/26/1999 1.38 121
2/27/1999 1.14 55
2/28/1999 0.83 55
3/1/1999 0.92 35
3/2/1999 0.62 42
3/3/1999 0.75 49
3/4/1999 0.72 22
3/5/1999 0.60 42
3/6/1999 0.46 19
3/7/1999 0.62 19
3/8/1999 0.36 7
3/9/1999 0.73 4
3/10/1999 1.07 2
3/11/1999 1.14 1
3/12/1999 1.15 1
3/13/1999 0.91 1
3/14/1999 0.70 1
3/15/1999 0.72 1
3/16/1999 0.82 1
3/17/1999 0.94 1
3/18/1999 1.00 4
3/19/1999 1.07 19
3/20/1999 0.83 152
3/21/1999 0.61 152
3/22/1999 0.69 204
3/23/1999 0.82 379
3/24/1999 0.94 471
3/25/1999 0.97 280
3/26/1999 1.00 380
3/27/1999 0.93 439
3/28/1999 0.79 441
3/29/1999 0.79 280
3/30/1999 1.03 819
3/31/1999 1.24 1140
4/1/1999 1.41 363
4/2/1999 1.40 627
4/3/1999 1.28 317
4/4/1999 1.01 316
4/5/1999 0.78 381
4/6/1999 0.95 206
4/7/1999 0.74 62
4/8/1999 1.24 20
4/9/1999 1.34 105
Final Report North Buffalo Creek Fecal Coliform TMDL A-3 Cone Mills WWTP Effluent Data
79
Date
Flow
(mgd)
FC
(#/100mL)
4/10/1999 1.09 123
4/11/1999 0.83 124
4/12/1999 0.79 105
4/13/1999 0.92 264
4/14/1999 0.99 127
4/15/1999 1.09 69
4/16/1999 1.09 281
4/17/1999 0.88 170
4/18/1999 0.74 170
4/19/1999 0.80 206
4/20/1999 1.01 122
4/21/1999 1.16 85
4/22/1999 1.31 92
4/23/1999 1.48 108
4/24/1999 1.31 163
4/25/1999 1.04 163
4/26/1999 1.04 254
4/27/1999 1.28 197
4/28/1999 1.32 234
4/29/1999 1.54 131
4/30/1999 1.41 106
5/1/1999 1.25 118
5/2/1999 1.21 118
5/3/1999 1.22 115
5/4/1999 1.32 119
5/5/1999 1.32 5
5/6/1999 1.34 26
5/7/1999 1.33 128
5/8/1999 1.29 134
5/9/1999 1.01 134
5/10/1999 1.04 197
5/11/1999 1.59 186
5/12/1999 1.55 197
5/13/1999 1.50 140
5/14/1999 1.44 287
5/15/1999 1.37 246
5/16/1999 1.23 247
5/17/1999 1.32 252
5/18/1999 1.47 305
5/19/1999 1.24 225
5/20/1999 1.32 328
5/21/1999 1.33 195
5/22/1999 1.30 157
5/23/1999 0.98 157
5/24/1999 0.84 69
5/25/1999 1.12 38
5/26/1999 1.39 239
Date
Flow
(mgd)
FC
(#/100mL)
5/27/1999 1.40 88
5/28/1999 1.08 136
5/29/1999 0.70 392
5/30/1999 0.69 390
5/31/1999 0.70 392
6/1/1999 1.09 136
6/2/1999 1.27 1200
6/3/1999 1.48 647
6/4/1999 1.66 260
6/5/1999 1.35 232
6/6/1999 1.23 234
6/7/1999 1.14 18
6/8/1999 1.29 8
6/9/1999 1.36 14
6/10/1999 1.78 46
6/11/1999 1.87 136
6/12/1999 1.75 82
6/13/1999 1.10 82
6/14/1999 1.00 80
6/15/1999 1.19 66
6/16/1999 1.25 591
6/17/1999 1.88 143
6/18/1999 1.30 781
6/19/1999 1.42 277
6/20/1999 1.32 276
6/21/1999 1.24 85
6/22/1999 1.32 97
6/23/1999 1.38 331
6/24/1999 1.30 331
6/25/1999 0.99 226
6/26/1999 0.70 486
6/27/1999 0.62 485
6/28/1999 0.59 305
6/29/1999 0.60 1081
6/30/1999 0.59 1332
7/1/1999 1.47 2
7/2/1999 1.30 669
7/3/1999 0.79 169
7/4/1999 0.84 169
7/5/1999 0.91 169
7/6/1999 1.22 2
7/7/1999 1.08 2
7/8/1999 0.96 2
7/9/1999 1.07 14
7/10/1999 1.12 58
7/11/1999 1.09 58
7/12/1999 1.25 82
Date
Flow
(mgd)
FC
(#/100mL)
7/13/1999 1.65 135
7/14/1999 1.82 1179
7/15/1999 1.57 135
7/16/1999 1.68 2
7/17/1999 1.39 975
7/18/1999 1.15 977
7/19/1999 1.24 468
7/20/1999 1.48 3296
7/21/1999 1.78 1010
7/22/1999 1.38 2
7/23/1999 1.41 2
7/24/1999 1.41 13
7/25/1999 1.12 13
7/26/1999 0.17 13
7/27/1999 0.27 2
7/28/1999 0.40 46
7/29/1999 1.00 2
7/30/1999 0.88 27
7/31/1999 0.65 21
8/1/1999 0.46 21
8/2/1999 0.43 39
8/3/1999 0.43 15
8/4/1999 0.67 7
8/5/1999 1.23 16
8/6/1999 1.16 82
8/7/1999 1.20 37
8/8/1999 1.12 37
8/9/1999 0.86 50
8/10/1999 1.10 1
8/11/1999 0.95 8
8/12/1999 0.86 17
8/13/1999 0.84 212
8/14/1999 1.04 86
8/15/1999 0.61 86
8/16/1999 0.74 86
8/17/1999 0.93 25
8/18/1999 1.15 88
8/19/1999 0.58 25
8/20/1999 1.12 4
8/21/1999 1.01 42
8/22/1999 0.94 26
8/23/1999 1.13 26
8/24/1999 1.14 27
8/25/1999 1.14 31
8/26/1999 1.14 4
8/27/1999 1.10 27
8/28/1999 1.00 49
Final Report North Buffalo Creek Fecal Coliform TMDL A-3 Cone Mills WWTP Effluent Data
80
Date
Flow
(mgd)
FC
(#/100mL)
8/29/1999 0.96 20
8/30/1999 0.97 20
8/31/1999 1.00 20
9/1/1999 1.00 1
9/2/1999 1.01 3
9/3/1999 1.00 1
9/4/1999 1.00 8
9/5/1999 0.98 8
9/6/1999 1.04 8
9/7/1999 1.01 13
9/8/1999 1.01 16
9/9/1999 0.99 55
9/10/1999 0.97 28
9/11/1999 1.01 23
9/12/1999 1.01 23
9/13/1999 1.00 4
9/14/1999 1.03 3
9/15/1999 1.48 4
9/16/1999 1.95 39
9/17/1999 1.25 58
9/18/1999 1.11 43
9/19/1999 0.97 43
9/20/1999 0.95 22
9/21/1999 0.92 54
9/22/1999 0.85 72
9/23/1999 0.99 38
9/24/1999 0.79 32
9/25/1999 0.73 62
9/26/1999 0.52 62
9/27/1999 0.65 38
9/28/1999 0.74 141
9/29/1999 0.90 8
9/30/1999 0.91 55
10/1/1999 1.93 7
10/2/1999 1.95 17
10/3/1999 0.58 17
10/4/1999 0.46 3
10/5/1999 1.00 2
10/6/1999 1.02 2
10/7/1999 1.02 3
10/8/1999 1.02 9
10/9/1999 1.02 6
10/10/1999 0.98 6
10/11/1999 0.97 7
10/12/1999 1.11 4
10/13/1999 10.10 28
10/14/1999 1.06 17
Date
Flow
(mgd)
FC
(#/100mL)
10/15/1999 1.06 25
10/16/1999 0.80 26
10/17/1999 0.69 25
10/18/1999 0.83 5
10/19/1999 0.75 55
10/20/1999 0.98 86
10/21/1999 1.01 24
10/22/1999 0.94 8
10/23/1999 0.89 115
10/24/1999 0.72 115
10/25/1999 0.83 285
10/26/1999 0.52 142
10/27/1999 0.63 196
10/28/1999 0.87 19
10/29/1999 0.87 27
10/30/1999 0.79 21
10/31/1999 0.82 22
11/1/1999 0.63 18
11/2/1999 0.66 22
11/3/1999 0.85 391
11/4/1999 0.54 119
11/5/1999 0.75 12
11/6/1999 0.73 81
11/7/1999 0.51 81
11/8/1999 0.42 12
11/9/1999 0.67 182
11/10/1999 0.63 106
11/11/1999 0.35 87
11/12/1999 0.77 6
11/13/1999 1.26 27
11/14/1999 0.97 27
11/15/1999 0.84 13
11/16/1999 1.02 2
11/17/1999 1.01 10
11/18/1999 1.03 4
11/19/1999 1.01 51
11/20/1999 0.99 139
11/21/1999 0.81 139
11/22/1999 0.20 200
11/23/1999 0.35 301
11/24/1999 0.81 38
11/25/1999 0.67 114
11/26/1999 0.44 112
11/27/1999 0.39 39
11/28/1999 0.39 39
11/29/1999 0.41 4
11/30/1999 0.99 2
Date
Flow
(mgd)
FC
(#/100mL)
12/1/1999 1.06 2
12/2/1999 1.00 58
12/3/1999 1.15 65
12/4/1999 1.05 123
12/5/1999 0.86 123
12/6/1999 0.91 270
12/7/1999 1.07 100
12/8/1999 1.11 188
12/9/1999 0.96 234
12/10/1999 0.88 96
12/11/1999 0.94 125
12/12/1999 0.93 125
12/13/1999 0.77 130
12/14/1999 0.67 40
12/15/1999 0.81 84
12/16/1999 1.18 67
12/17/1999 0.57 5
12/18/1999 0.77 174
12/19/1999 0.60 174
12/20/1999 0.60 355
12/21/1999 0.66 268
12/22/1999 0.68 337
12/23/1999 0.52 155
12/24/1999 0.72 155
12/25/1999 0.65 155
12/26/1999 0.41 155
12/27/1999 0.36 155
12/28/1999 0.29 12
12/29/1999 0.55 3
12/30/1999 0.45 5
12/31/1999 0.44 5
1/1/2000 0.44 5
1/2/2000 0.54 5
1/3/2000 0.94 10
1/4/2000 1.08 1
1/5/2000 1.03 1
1/6/2000 0.32 1
1/7/2000 0.49 54
1/8/2000 0.67 75
1/9/2000 0.98 75
1/10/2000 1.09 165
1/11/2000 0.99 80
1/12/2000 0.95 80
1/13/2000 0.59 117
1/14/2000 0.50 299
1/15/2000 0.49 252
1/16/2000 0.51 252
Final Report North Buffalo Creek Fecal Coliform TMDL A-3 Cone Mills WWTP Effluent Data
81
Date
Flow
(mgd)
FC
(#/100mL)
1/17/2000 0.50 360
1/18/2000 0.38 232
1/19/2000 0.40 620
1/20/2000 0.68 243
1/21/2000 0.78 165
1/22/2000 0.99 138
1/23/2000 0.97 138
1/24/2000 0.90 5
1/25/2000 0.60 73
1/26/2000 0.56 35
1/27/2000 0.54 86
1/28/2000 0.55 56
1/29/2000 0.07 159
1/30/2000 0.70 184
1/31/2000 0.80 184
2/1/2000 0.99 257
2/2/2000 0.97 238
2/3/2000 0.99 346
2/4/2000 1.00 311
2/5/2000 0.92 270
2/6/2000 0.84 270
2/7/2000 0.84 208
2/8/2000 1.02 216
2/9/2000 1.06 231
2/10/2000 1.06 95
2/11/2000 1.09 100
2/12/2000 1.13 72
2/13/2000 1.09 72
2/14/2000 1.11 83
2/15/2000 1.22 9
2/16/2000 1.27 24
2/17/2000 1.32 194
2/18/2000 1.37 105
2/19/2000 1.39 80
2/20/2000 1.07 81
2/21/2000 1.08 19
2/22/2000 0.93 4
2/23/2000 1.15 101
2/24/2000 1.23 262
2/25/2000 1.21 246
2/26/2000 0.91 245
2/27/2000 0.85 245
2/28/2000 0.85 365
2/29/2000 0.94 110
3/1/2000 0.94 130
3/2/2000 0.92 310
3/3/2000 0.89 92
Date
Flow
(mgd)
FC
(#/100mL)
3/4/2000 0.94 119
3/5/2000 0.91 119
3/6/2000 0.90 54
3/7/2000 0.91 21
3/8/2000 1.21 32
3/9/2000 1.19 31
3/10/2000 1.07 46
3/11/2000 1.06 51
3/12/2000 0.99 51
3/13/2000 0.99 74
3/14/2000 1.03 53
3/15/2000 1.05 39
3/16/2000 1.32 59
3/17/2000 1.18 88
3/18/2000 1.04 80
3/19/2000 1.04 80
3/20/2000 0.92 98
3/21/2000 0.86 75
3/22/2000 1.12 37
3/23/2000 1.01 16
3/24/2000 1.05 1
3/25/2000 0.99 5
3/26/2000 0.80 5
3/27/2000 0.77 1
3/28/2000 0.96 1
3/29/2000 1.20 5
3/30/2000 1.15 28
3/31/2000 1.20 68
4/1/2000 1.24 66
4/2/2000 1.12 66
4/3/2000 1.26 117
4/4/2000 1.18 51
4/5/2000 1.10 35
4/6/2000 0.93 66
4/7/2000 0.67 50
4/8/2000 0.72 54
4/9/2000 0.65 54
4/10/2000 0.73 67
4/11/2000 0.93 32
4/12/2000 0.97 98
4/13/2000 1.12 72
4/14/2000 1.00 99
4/15/2000 1.08 46
4/16/2000 0.96 46
4/17/2000 1.07 46
4/18/2000 0.99 10
4/19/2000 1.00 2
Date
Flow
(mgd)
FC
(#/100mL)
4/20/2000 1.17 66
4/21/2000 1.41 20
4/22/2000 1.30 20
4/23/2000 0.78 20
4/24/2000 1.01 1
4/25/2000 1.01 11
4/26/2000 0.65 13
4/27/2000 0.87 3
4/28/2000 0.91 4
4/29/2000 0.77 3
4/30/2000 0.69 3
5/1/2000 0.97 1
5/2/2000 0.91 3
5/3/2000 0.96 6
5/4/2000 1.07 31
5/5/2000 1.04 8
5/6/2000 0.99 11
5/7/2000 0.87 11
5/8/2000 0.96 4
5/9/2000 0.74 1
5/10/2000 0.78 3
5/11/2000 0.88 2
5/12/2000 0.91 1
5/13/2000 0.89 1
5/14/2000 0.79 1
5/15/2000 0.82 1
5/16/2000 0.80 1
5/17/2000 0.87 29
5/18/2000 0.95 2
5/19/2000 1.06 3
5/20/2000 1.06 14
5/21/2000 0.95 13
5/22/2000 0.92 27
5/23/2000 0.93 22
5/24/2000 0.79 9
5/25/2000 0.59 6
5/26/2000 0.84 59
5/27/2000 0.84 17
5/28/2000 0.84 17
5/29/2000 0.84 17
5/30/2000 0.85 2
5/31/2000 0.85 2
6/1/2000 0.85 27
6/2/2000 0.84 121
6/3/2000 0.84 53
6/4/2000 0.84 53
6/5/2000 0.85 18
Final Report North Buffalo Creek Fecal Coliform TMDL A-3 Cone Mills WWTP Effluent Data
82
Date
Flow
(mgd)
FC
(#/100mL)
6/6/2000 0.84 47
6/7/2000 0.84 27
6/8/2000 0.72 89
6/9/2000 0.70 108
6/10/2000 0.07 69
6/11/2000 0.70 69
6/12/2000 0.96 50
6/13/2000 0.95 31
6/14/2000 0.95 121
6/15/2000 0.96 33
6/16/2000 0.91 89
6/17/2000 0.81 148
6/18/2000 0.81 148
6/19/2000 0.81 188
6/20/2000 0.96 280
6/21/2000 1.28 229
6/22/2000 0.96 89
6/23/2000 1.01 116
6/24/2000 0.91 99
6/25/2000 0.91 99
6/26/2000 0.91 131
6/27/2000 1.30 58
6/28/2000 0.91 64
6/29/2000 0.81 241
6/30/2000 0.81 247
7/1/2000 0.81 217
7/2/2000 0.81 217
7/3/2000 0.81 164
7/4/2000 0.81 136
7/5/2000 0.91 58
7/6/2000 1.01 75
7/7/2000 1.01 129
7/8/2000 1.12 197
7/9/2000 1.12 197
7/10/2000 1.12 360
7/11/2000 0.81 224
7/12/2000 0.81 193
7/13/2000 0.81 106
7/14/2000 0.81 142
7/15/2000 0.81 63
7/16/2000 0.81 63
7/17/2000 0.81 1
7/18/2000 1.01 2
7/19/2000 1.34 16
7/20/2000 1.12 1
7/21/2000 1.01 14
7/22/2000 1.01 97
Date
Flow
(mgd)
FC
(#/100mL)
7/23/2000 1.01 97
7/24/2000 1.01 127
7/25/2000 1.01 248
7/26/2000 1.01 137
7/27/2000 1.34 184
7/28/2000 1.34 268
7/29/2000 1.34 187
7/30/2000 1.01 187
7/31/2000 0.81 51
8/1/2000 1.01 247
8/2/2000 1.01 212
8/3/2000 1.01 170
8/4/2000 1.01 229
8/5/2000 1.01 122
8/6/2000 0.91 122
8/7/2000 0.30 51
8/8/2000 1.01 37
8/9/2000 0.82 48
8/10/2000 1.11 268
8/11/2000 1.16 135
8/12/2000 1.14 102
8/13/2000 1.10 102
8/14/2000 1.55 2
8/15/2000 1.43 2
8/16/2000 0.89 13
8/17/2000 1.24 7
8/18/2000 1.28 20
8/19/2000 0.98 33
8/20/2000 0.51 33
8/21/2000 0.87 59
8/22/2000 0.96 44
8/23/2000 1.01 25
8/24/2000 0.91 212
8/25/2000 1.01 217
8/26/2000 1.01 211
8/27/2000 1.01 211
8/28/2000 1.01 124
8/29/2000 1.06 291
8/30/2000 1.06 87
8/31/2000 1.06 189
9/1/2000 1.06 189
9/2/2000 1.06 218
9/3/2000 1.06 218
9/4/2000 1.06 218
9/5/2000 1.06 68
9/6/2000 0.95 427
9/7/2000 0.88 1
Date
Flow
(mgd)
FC
(#/100mL)
9/8/2000 1.17 1
9/9/2000 1.09 57
9/10/2000 1.04 57
9/11/2000 0.93 102
9/12/2000 0.70 123
9/13/2000 0.73 101
9/14/2000 1.02 158
9/15/2000 1.32 529
9/16/2000 1.10 427
9/17/2000 0.77 425
9/18/2000 0.96 621
9/19/2000 1.29 394
9/20/2000 1.06 210
9/21/2000 1.06 286
9/22/2000 1.06 900
9/23/2000 1.06 358
9/24/2000 1.06 358
9/25/2000 1.02 244
9/26/2000 1.02 2
9/27/2000 1.02 1
9/28/2000 1.01 77
9/29/2000 0.48 138
9/30/2000 1.20 76
10/1/2000 1.36 76
10/2/2000 0.69 56
10/3/2000 0.57 33
10/4/2000 0.54 32
10/5/2000 0.76 60
10/6/2000 1.83 164
10/7/2000 1.31 140
10/8/2000 0.54 141
10/9/2000 0.76 113
10/10/2000 1.01 225
10/11/2000 1.06 242
10/12/2000 1.08 225
10/13/2000 1.08 354
10/14/2000 0.71 208
10/15/2000 0.60 208
10/16/2000 0.60 118
10/17/2000 1.18 138
10/18/2000 1.27 332
10/19/2000 1.17 225
10/20/2000 1.18 200
10/21/2000 0.92 218
10/22/2000 0.70 218
10/23/2000 0.54 174
10/24/2000 0.37 272
Final Report North Buffalo Creek Fecal Coliform TMDL A-3 Cone Mills WWTP Effluent Data
83
Date
Flow
(mgd)
FC
(#/100mL)
10/25/2000 0.84 227
10/26/2000 1.25 238
10/27/2000 1.14 217
10/28/2000 0.51 230
10/29/2000 0.46 230
10/30/2000 0.51 140
10/31/2000 0.63 325
11/1/2000 0.89 108
11/2/2000 1.18 179
11/3/2000 0.88 181
11/4/2000 0.88 4674
11/5/2000 0.88 4674
11/6/2000 0.53 310
11/7/2000 0.59 18054
11/8/2000 0.59 42
11/9/2000 1.20 70
11/10/2000 1.10 104
11/11/2000 0.96 104
11/12/2000 0.72 104
11/13/2000 0.52 89
11/14/2000 0.61 213
11/15/2000 0.72 104
11/16/2000 1.04 170
11/17/2000 1.44 258
11/18/2000 1.13 193
11/19/2000 0.63 193
11/20/2000 0.57 105
11/21/2000 0.58 237
11/22/2000 0.91 105
11/23/2000 1.55 167
11/24/2000 1.39 108
11/25/2000 1.37 180
11/26/2000 0.60 180
11/27/2000 0.99 219
11/28/2000 1.22 213
11/29/2000 1.24 105
11/30/2000 1.30 219
12/1/2000 1.23 195
12/2/2000 0.77 216
12/3/2000 0.42 216
12/4/2000 0.21 239
12/5/2000 0.52 214
12/6/2000 0.85 160
12/7/2000 0.84 243
12/8/2000 1.02 173
12/9/2000 0.97 150
12/10/2000 0.83 150
Date
Flow
(mgd)
FC
(#/100mL)
12/11/2000 1.12 75
12/12/2000 1.12 108
12/13/2000 1.03 235
12/14/2000 1.10 304
12/15/2000 1.16 400
12/16/2000 1.22 322
12/17/2000 0.99 322
12/18/2000 0.94 272
12/19/2000 1.10 307
12/20/2000 1.06 160
12/21/2000 1.13 308
12/22/2000 0.88 244
12/23/2000 0.26 193
12/24/2000 0.58 192
12/25/2000 0.75 192
12/26/2000 0.94 192
12/27/2000 0.91 192
12/28/2000 0.91 115
12/29/2000 0.88 102
12/30/2000 0.94 122
12/31/2000 1.11 122
1/1/2001 0.54 122
1/2/2001 0.68 74
1/3/2001 1.25 198
1/4/2001 1.30 268
1/5/2001 1.44 110
1/6/2001 1.25 186
1/7/2001 1.10 186
1/8/2001 1.06 177
1/9/2001 0.83 189
1/10/2001 0.77 222
1/11/2001 0.86 238
1/12/2001 0.98 138
1/13/2001 0.90 182
1/14/2001 0.47 182
1/15/2001 0.33 182
1/16/2001 0.83 168
1/17/2001 0.79 354
1/18/2001 1.10 355
1/19/2001 1.20 279
1/20/2001 1.03 292
1/21/2001 0.78 292
1/22/2001 0.75 263
1/23/2001 0.95 272
1/24/2001 1.03 205
1/25/2001 0.91 123
1/26/2001 0.97 123
Date
Flow
(mgd)
FC
(#/100mL)
1/27/2001 0.95 123
1/28/2001 0.89 123
1/29/2001 0.91 123
1/30/2001 0.96 123
1/31/2001 1.14 123
2/1/2001 1.55 5
2/2/2001 1.44 11
2/3/2001 1.02 29
2/4/2001 0.86 29
2/5/2001 0.85 51
2/6/2001 0.87 48
2/7/2001 0.88 26
2/8/2001 0.89 69
2/9/2001 0.93 106
2/10/2001 0.67 56
2/11/2001 0.54 56
2/12/2001 0.61 27
2/13/2001 0.71 22
2/14/2001 0.77 35
2/15/2001 0.87 18
2/16/2001 1.30 42
2/17/2001 1.34 29
2/18/2001 1.12 29
2/19/2001 0.95 54
2/20/2001 1.10 2
2/21/2001 1.16 4
2/22/2001 1.21 4
2/23/2001 1.16 3
2/24/2001 1.18 3
2/25/2001 1.13 3
2/26/2001 0.86 2
2/27/2001 1.23 2
2/28/2001 0.56 10
3/1/2001 1.06 8
3/2/2001 1.13 292
3/3/2001 1.49 121
3/4/2001 0.87 121
3/5/2001 0.47 70
3/6/2001 0.95 114
3/7/2001 0.47 175
3/8/2001 1.13 70
3/9/2001 1.14 70
3/10/2001 1.07 169
3/11/2001 0.72 168
3/12/2001 0.68 168
3/13/2001 1.14 169
3/14/2001 1.09 169
Final Report North Buffalo Creek Fecal Coliform TMDL A-3 Cone Mills WWTP Effluent Data
84
Date
Flow
(mgd)
FC
(#/100mL)
3/15/2001 1.16 168
3/16/2001 1.10 268
3/17/2001 0.89 233
3/18/2001 0.54 233
3/19/2001 0.70 266
3/20/2001 1.46 330
3/21/2001 1.19 268
3/22/2001 1.08 200
3/23/2001 0.99 230
3/24/2001 0.61 204
3/25/2001 0.45 204
3/26/2001 0.98 210
3/27/2001 1.09 175
3/28/2001 1.12 70
3/29/2001 1.30 70
3/30/2001 1.15 241
3/31/2001 0.98 238
4/1/2001 0.90 238
4/2/2001 0.90 270
4/3/2001 1.73 370
4/4/2001 1.60 110
4/5/2001 1.48 80
4/6/2001 1.00 89
4/7/2001 0.71 78
4/8/2001 0.47 78
4/9/2001 0.90 96
4/10/2001 1.01 48
4/11/2001 1.16 50
4/12/2001 1.26 24
4/13/2001 1.26 35
4/14/2001 0.91 35
4/15/2001 0.66 35
4/16/2001 1.08 27
4/17/2001 1.03 40
4/18/2001 0.98 44
4/19/2001 0.94 37
Date
Flow
(mgd)
FC
(#/100mL)
4/20/2001 1.04 25
4/21/2001 0.93 35
4/22/2001 0.76 35
4/23/2001 0.89 48
4/24/2001 0.84 30
4/25/2001 1.21 34
4/26/2001 1.03 10
4/27/2001 1.30 14
4/28/2001 0.89 8
4/29/2001 0.81 8
4/30/2001 0.73 4
5/1/2001 0.80 13
5/2/2001 0.86 3
5/3/2001 0.92 16
5/4/2001 0.93 19
5/5/2001 0.90 12
5/6/2001 0.66 12
5/7/2001 0.63 8
5/8/2001 0.99 5
5/9/2001 1.19 28
5/10/2001 1.10 228
5/11/2001 0.98 21
5/12/2001 0.87 69
5/13/2001 0.44 70
5/14/2001 0.51 70
5/15/2001 1.14 3
5/16/2001 1.23 13
5/17/2001 1.12 26
5/18/2001 1.08 16
5/19/2001 0.87 9
5/20/2001 0.51 8
5/21/2001 0.75 13
5/22/2001 1.01 2
5/23/2001 0.99 21
5/24/2001 0.97 6
5/25/2001 1.16 65
Date
Flow
(mgd)
FC
(#/100mL)
5/26/2001 0.97 56
5/27/2001 0.63 56
5/28/2001 0.72 56
5/29/2001 0.85 66
5/30/2001 0.80 86
5/31/2001 1.07 90
6/1/2001 1.09 41
6/2/2001 0.45 38
6/3/2001 0.50 38
6/4/2001 0.78 7
6/5/2001 0.88 13
6/6/2001 1.01 16
6/7/2001 0.94 22
6/8/2001 0.78 33
6/9/2001 0.59 24
6/10/2001 0.50 25
6/11/2001 0.76 12
6/12/2001 0.95 31
6/13/2001 0.98 24
6/14/2001 0.96 31
6/15/2001 0.92 57
6/16/2001 0.85 39
6/17/2001 0.53 39
6/18/2001 0.68 30
6/19/2001 0.83 38
6/20/2001 0.83 22
6/21/2001 0.85 25
6/22/2001 0.96 35
6/23/2001 0.79 33
6/24/2001 0.54 33
6/25/2001 0.48 28
6/26/2001 0.71 45
6/27/2001 0.78 91
6/28/2001 0.76 103
6/29/2001 0.73 76
6/30/2001 0.70 76

Final Report North Buffalo Creek Fecal Coliform TMDL A-4 Mecklenburg Co. Dry Weather Flow Study Data
85






0

!> 9

$

 ;

$
0

!> 9

$

 ;

$
0

!> 9

$

 ;

$
0

!> 9

$

 ;

$

Data from Mecklenburg County dry weather flow study (Kroening, 2002). Flow and fecal
coliform concentrations from outfalls found to possess dry weather flow. These data were used
to support calculations associated with dry weather flow/illicit discharges from stormwater outfalls
in the North Buffalo Creek TMDL subwatersheds.

Outfall Flow
(cfs)
Fecal coliform
(#/100mL)
1 0.02000 6,000
2 0.13000 100
3 0.02000 100
4 0.00200 15,000
5 0.01800 100
6 0.00020 2,700
7 0.00100 600
8 0.01400 4,600
9 0.00800 100
10 0.01100 100
11 0.00550 6,000
12 0.04170 100
13 0.00900 200
14 0.00070 6,000
15 0.00010 8,000
16 0.00050 6,000
17 0.03500 6,600
18 0.00800 100
19 0.00060 100
20 0.00020 1,200
21 0.00350 100
22 0.00520 100
Final Report North Buffalo Creek Fecal Coliform TMDL A-5 Mecklenburg Co. Ground Water Study Data
86









1111

!> 9



!> 9



!> 9



!> 9







$

$

$

$

Data from Mecklenburg County ground water study (Kroening, 2002). Fecal coliform
concentrations in ground water sampled from wells up and down gradient from sanitary sewer
lines. These data were used to support calculations associated with exfiltrating sanitary sewer
lines in the North Buffalo Creek TMDL subwatersheds.

Site Date
MW-2
(Upgradient)
Fecal coliform
(#/100 ml)
MW-1
(Downgradient)
Fecal coliform
(#/100 ml)
Beatties Ford Road 11/13/2000 <200 <200
Beatties Ford Road 11/20/2000 <10 <200
Beatties Ford Road 11/28/2000 <10 <10
Beatties Ford Road 12/5/2000 <10 <10
Latta Park 11/16/2000 - <200
Latta Park 11/20/2000 - <10
Latta Park 11/28/2000 - <10
Latta Park 12/5/2000 - <10
Latta Park 12/13/2000 - <10
Latta Park 12/20/2000 - <10
Latta Park 12/27/2000 - <10
Latta Park 7/11/2001 - <10
Masonic 11/16/2000 <200 <200
Masonic 11/20/2000 <200 <200
Masonic 11/28/2000 <10 1,700
Masonic 12/5/2000 <10 80
Masonic 12/14/2000 <10 <10
Masonic 12/20/2000 <10 <10
Masonic 12/27/2000 <10 <10
Masonic 7/11/2001 <10 <10
McDonald 11/13/2000 <200 330
McDonald 11/20/2000 <10 <200
McDonald 11/28/2000 <20 30
McDonald 12/5/2000 <10 <10
McDonald 12/13/2000 <10 <10
McDonald 12/20/2000 <10 20
McDonald 12/27/2000 <10 <10
McDonald 7/11/2001 <10 <10
Meadowbrook 11/13/2000 2000 <200
Meadowbrook 11/20/2000 30 <200
Meadowbrook 11/28/2000 <10 <10
Meadowbrook 12/6/2000 <10 <10
Final Report North Buffalo Creek Fecal Coliform TMDL A-5 Mecklenburg Co. Ground Water Study Data
87
Site Date
MW-2
(Upgradient)
Fecal coliform
(#/100 ml)
MW-1
(Downgradient)
Fecal coliform
(#/100 ml)
Meadowbrook 12/20/2000 <10 <10
Meadowbrook 12/27/2000 <10 <10
Mint Museum 11/13/2000 <200 <200
Mint Museum 11/20/2000 <200 <200
Mint Museum 11/28/2000 <10 <10
Mint Museum 12/6/2000 <10 <10
Sharon View 11/16/2000 <200 <200
Sharon View 11/20/2000 <10 <10
Sharon View 11/28/2000 <10 <10
Sharon View 12/5/2000 <10 <10
Sharon View 12/21/2000 <10 <10
Sharon View 12/27/2000 <10 <10
Southwest Blvd. 11/13/2000 <200 <200
Southwest Blvd. 11/20/2000 <200 <200
Southwest Blvd. 11/28/2000 <10 <10
Southwest Blvd. 12/5/2000 <10 <10
Thermal Road 11/16/2000 <200 <200
Thermal Road 11/21/2000 <200 <200
Thermal Road 11/29/2000 <10 140
Thermal Road 12/5/2000 <10 30
Thermal Road 12/21/2000 <10 <10
Thermal Road 12/27/2000 <10 <10
Thermal Road 7/11/2001 40 100

Final Report North Buffalo Creek Fecal Coliform TMDL A-6 Sewer System Overflows
88



5

;


* ; 

5

;


* ; 

5

;


* ; 

5

;


* ;

SSOs in subwatershed 1 during the model simulation period. Source: City of Greensboro
Department of Water Resources.

Date
Start/Stop
hour used in
model
Flow
(cfs)
Fecal coliform load
(#/hr)
1998/10/29 15:00 (start) 0.00186 1.21E+10
1998/10/29 16:00 (stop)

1998/12/05 09:00 0.00062 4.04E+09
1998/12/05 12:00

1998/12/20 14:00 0.00037 2.42E+09
1998/12/20 17:00

1998/12/28 10:00 0.00186 1.21E+10
1998/12/28 11:00

1999/01/29 15:00 0.00093 6.06E+09
1999/01/29 17:00

1999/03/10 07:00 0.00743 4.85E+10
1999/03/10 08:00

1999/03/17 10:00 0.00031 2.02E+09
1999/03/17 13:00

1999/06/26 09:00 0.00124 8.08E+09
1999/06/26 12:00

1999/11/14 12:00 0.00031 2.02E+09
1999/11/15 12:00

1999/11/26 12:00 0.00464 3.03E+10
1999/11/26 16:00
Final Report North Buffalo Creek Fecal Coliform TMDL A-6 Sewer System Overflows
89

SSOs in subwatershed 1 - continued
Date
Start/Stop
hour used in
model
Flow
(cfs)
Fecal coliform load
(#/hr)
1999/12/04 16:00 0.00093 6.06E+09
1999/12/04 18:00

1999/12/29 15:00 0.00371 2.42E+10
1999/12/29 17:00

1999/12/31 16:00 0.00149 9.69E+09
1999/12/31 21:00

2000/01/07 08:00 0.00743 4.85E+10
2000/01/07 09:00

2000/01/11 09:00 0.00186 1.21E+10
2000/01/11 11:00

2000/03/11 13:00 0.01485 9.69E+10
2000/03/11 18:00

2000/03/13 12:00 0.00093 6.06E+09
2000/03/13 13:00

2000/03/23 12:00 0.00046 3.03E+09
2000/03/23 14:00

2000/03/24 09:00 0.00046 3.03E+09
2000/03/24 13:00

2000/09/19 16:00 0.00371 2.42E+10
2000/09/19 17:00

2000/09/27 19:00 0.00464 3.03E+10
2000/09/27 23:00

2000/10/11 11:00 0.00012 8.08E+08
2000/10/11 14:00

2001/01/06 18:00 0.00111 7.27E+09
2001/01/06 23:00

Final Report North Buffalo Creek Fecal Coliform TMDL A-6 Sewer System Overflows
90
SSOs in subwatershed 1 - continued
Date
Start/Stop
hour used in
model
Flow
(cfs)
Fecal coliform load
(#/hr)
2001/04/10 10:00 0.00012 8.08E+08
2001/04/10 13:00

2001/04/22 17:00 0.01300 8.48E+10
2001/04/22 19:00

Final Report North Buffalo Creek Fecal Coliform TMDL A-6 Sewer System Overflows
91
SSOs in subwatershed 2 during the model simulation period. Source: City of Greensboro
Department of Water Resources.

Date
Start/Stop
hour used in
model
Flow
(cfs)
Fecal coliform load
(#/hr)
3/1/1999 20:00 (start) 0.00173 1.13E+10
3/1/1999 24:00 (stop)

6/18/1999 12:00 0.00086 5.59E+09
6/18/1999 14:00

9/8/1999 12:00 0.00743 4.85E+10
9/8/1999 13:00

9/19/1999 8:00 0.00301 1.96E+10
9/19/1999 11:00

10/7/1999 13:00 0.00053 3.46E+09
10/7/1999 15:00

10/13/1999 17:00 0.00134 8.72E+09
10/13/1999 18:00

5/19/2000 13:00 0.00093 6.06E+09
5/19/2000 14:00

6/20/2000 8:00 0.00474 3.09E+10
6/20/2000 9:00

7/2/2000 16:00 0.00906 5.91E+10
7/2/2000 19:00

7/4/2000 19:00 0.00127 8.26E+09
7/4/2000 21:00

7/7/2000 18:00 0.01921 1.25E+11
7/7/2000 19:00

7/7/2000 18:00 0.00113 7.34E+09
7/7/2000 20:00

8/19/2000 11:00 0.00025 1.65E+09
8/19/2000 13:00
Final Report North Buffalo Creek Fecal Coliform TMDL A-6 Sewer System Overflows
92
SSOs in subwatershed 2 - continued
Date
Start/Stop
hour used in
model
Flow
(cfs)
Fecal coliform load
(#/hr)
12/6/2000 8:00 0.01160 7.57E+10
12/6/2000 10:00

12/7/2000 14:00 0.04285 2.80E+11
12/7/2000 15:00

1/1/2001 17:00 0.00142 9.28E+09
1/1/2001 21:00

1/16/2001 13:00 0.00028 1.82E+09
1/16/2001 15:00

1/16/2001 8:00 0.05570 3.63E+11
1/16/2001 9:00

Final Report North Buffalo Creek Fecal Coliform TMDL A-6 Sewer System Overflows
93
SSOs in subwatershed 3 during the model simulation period. Source: City of Greensboro
Department of Water Resources.

Date
Start/Stop
hour used in
model
Flow
(cfs)
Fecal coliform load
(#/hr)
2/21/2000 17:00 (start) 0.00356 6.52E+12
2/21/2000 20:00 (stop)

Final Report North Buffalo Creek Fecal Coliform TMDL A-6 Sewer System Overflows
94
SSOs in subwatershed 4 during the model simulation period. Source: City of Greensboro
Department of Water Resources.

Date
Start/Stop
hour used
in model
Flow
(cfs)
Fecal coliform load
(#/hr)
9/14/1998 9:00 (start) 0.00074 4.85E+09
9/14/1998 11:00 (stop)

12/13/1998 13:00 0.02153 1.40E+11
12/13/1998 17:00

12/24/1998 11:00 0.14417 9.41E+11
12/24/1998 14:00

1/2/1999 10:00 0.00147 9.56E+09
1/2/1999 12:00

1/7/1999 8:00 0.00088 5.77E+09
1/7/1999 10:00

1/7/1999 8:00 0.00177 1.15E+10
1/7/1999 11:00

1/21/1999 11:00 0.00056 3.63E+09
1/21/1999 13:00

2/24/1999 14:00 0.00014 8.94E+08
2/25/1999 11:00

4/13/1999 11:00 0.00117 7.65E+09
4/13/1999 15:00

4/13/1999 12:00 0.00619 4.04E+10
4/13/1999 15:00

4/21/1999 10:00 0.00099 6.46E+09
4/21/1999 11:00

4/23/1999 9:00 0.00768 5.01E+10
4/23/1999 10:00

4/30/1999 7:00 0.24866 1.62E+12
4/30/1999 15:00
Final Report North Buffalo Creek Fecal Coliform TMDL A-6 Sewer System Overflows
95
SSOs in subwatershed 4 – continued
Date
Start/Stop
hour used
in model
Flow
(cfs)
Fecal coliform load
(#/hr)
7/1/1999 12:00 0.01238 8.08E+10
7/1/1999 15:00

9/1/1999 12:00 0.00025 1.62E+09
9/1/1999 13:00

9/29/1999 14:00 0.01114 7.27E+10
9/29/1999 15:00

10/1/1999 14:00 0.00023 1.50E+09
10/1/1999 16:00

1/8/2000 9:00 0.00099 6.43E+09
1/8/2000 11:00

1/14/2000 10:00 0.00107 6.99E+09
1/14/2000 12:00

1/19/2000 12:00 0.00092 5.97E+09
1/19/2000 14:00

1/26/2000 8:00 0.00098 6.38E+09
1/26/2000 10:00

3/9/2000 13:00 0.00111 7.27E+09
3/9/2000 15:00

5/22/2000 14:00 0.00025 1.62E+09
5/22/2000 15:00

6/11/2000 17:00 0.00166 1.08E+10
6/11/2000 19:00

6/28/2000 22:00 0.00174 1.14E+10
6/29/2000 1:00

6/29/2000 10:00 0.00594 3.88E+10
6/29/2000 12:00
Final Report North Buffalo Creek Fecal Coliform TMDL A-6 Sewer System Overflows
96

SSOs in subwatershed 4 – continued
Date
Start/Stop
hour used
in model
Flow
(cfs)
Fecal coliform load
(#/hr)
8/22/2000 16:00 0.03229 2.11E+11
8/22/2000 19:00

9/7/2000 8:00 0.01447 9.44E+10
9/7/2000 10:00

9/15/2000 12:00 0.00248 1.62E+10
9/15/2000 15:00

9/27/2000 17:00 0.00265 1.73E+10
9/27/2000 18:00

10/27/2000 8:00 0.00039 2.55E+09
10/27/2000 13:00

11/10/2000 11:00 0.00446 2.91E+10
11/10/2000 12:00

12/8/2000 15:00 0.00315 2.06E+10
12/8/2000 16:00

1/31/2001 11:00 0.01485 9.69E+10
1/31/2001 12:00

3/8/2001 10:00 0.00037 2.42E+09
3/8/2001 11:00

6/20/2001 12:00 0.00248 1.62E+10
6/20/2001 15:00

6/27/2001 10:00 0.00186 1.21E+10
6/27/2001 11:00

7/4/2001 11:00 0.01238 8.08E+10
7/4/2001 13:00

7/30/2001 13:00 0.00019 1.21E+09
7/30/2001 14:00

Final Report North Buffalo Creek Fecal Coliform TMDL A-6 Sewer System Overflows
97
SSOs in subwatershed 5 during the model simulation period. Source: City of Greensboro
Department of Water Resources.

Date
Start/Stop
hour used
in model
Flow
(cfs)
Fecal coliform load
(#/hr)
2/22/1999 15:00 (start) 0.00637 4.15E+10
2/22/1999 17:00 (stop)

4/20/1999 11:00 0.01547 1.01E+11
4/20/1999 13:00

6/1/2000 12:00 0.00036 2.34E+09
6/1/2000 13:00

7/27/2000 13:00 0.00477 3.11E+10
7/27/2000 14:00

7/28/2000 13:00 0.02958 1.93E+11
7/28/2000 15:00

7/28/2000 11:00 0.00175 1.14E+10
7/28/2000 16:00

6/8/2001 9:00 0.02228 1.45E+11
6/8/2001 10:00

Final Report North Buffalo Creek Fecal Coliform TMDL A-6 Sewer System Overflows
98
SSOs in subwatersheds 6.1 & 6.2 during the model simulation period. Source: City of
Greensboro Department of Water Resources.

Date
Start/Stop
hour used
in model
Flow
(cfs)
Fecal coliform load
(#/hr)
1/30/1999 14:00 (start) 0.00159 1.04E+10
1/30/1999 17:00 (stop)

2/11/1999 16:00 0.00696 4.54E+10
2/11/1999 18:00

3/4/1999 9:00 0.01375 8.97E+10
3/4/1999 11:00

3/19/1999 8:00 0.00679 4.43E+10
3/19/1999 10:00

4/1/1999 20:00 0.00201 1.31E+10
4/1/1999 22:00

4/14/1999 13:00 0.01342 8.76E+10
4/14/1999 15:00

10/15/1999 10:00 0.00093 6.06E+09
10/15/1999 11:00

10/29/1999 9:00 0.03713 2.42E+11
10/29/1999 11:00

11/2/1999 10:00 0.00637 4.15E+10
11/2/1999 12:00

12/23/1999 10:00 0.00371 2.42E+10
12/23/1999 11:00

1/11/2000 21:00 0.00061 3.96E+09
1/12/2000 4:00

2/7/2000 13:00 0.00124 8.08E+09
2/7/2000 15:00
Final Report North Buffalo Creek Fecal Coliform TMDL A-6 Sewer System Overflows
99

SSOs in subwatersheds 6.1 & 6.2 - continued
Date
Start/Stop
hour used
in model
Flow
(cfs)
Fecal coliform load
(#/hr)
2/21/2000 15:00 0.00365 2.38E+10
2/21/2000 18:00

3/15/2000 11:00 0.00248 1.62E+10
3/15/2000 13:00

4/25/2000 16:00 0.00191 1.25E+10
4/25/2000 19:00

5/4/2000 14:00 0.00149 9.69E+09
5/4/2000 17:00

5/23/2000 8:00 0.00371 2.42E+10
5/23/2000 10:00

6/10/2000 23:00 0.00321 2.10E+10
6/11/2000 1:00

8/7/2000 12:00 0.00052 3.38E+09
8/7/2000 14:00

9/3/2000 22:00 0.00259 1.69E+10
9/3/2000 24:00

11/30/2000 8:00 0.00535 3.49E+10
11/30/2000 11:00

2/7/2001 9:00 0.04165 2.72E+11
2/7/2001 11:00

2/22/2001 7:00 0.01663 1.08E+11
2/22/2001 9:00

3/27/2001 10:00 0.01013 6.61E+10
3/27/2001 12:00

4/4/2001 14:00 0.00011 7.13E+08
4/5/2001 10:00
Final Report North Buffalo Creek Fecal Coliform TMDL A-6 Sewer System Overflows
100
SSOs in subwatersheds 6.1 & 6.2 - continued
Date
Start/Stop
hour used
in model
Flow
(cfs)
Fecal coliform load
(#/hr)
5/7/2001 19:00 0.00413 2.69E+10
5/7/2001 21:00

7/20/2001 12:00 0.00016 1.04E+09
7/20/2001 15:00

Final Report North Buffalo Creek Fecal Coliform TMDL A-6 Sewer System Overflows
101
SSOs in Subwatershed 7 during the model simulation period. Source: City of Greensboro
Department of Water Resources.

SSOs in Subwatershed 7
Date
Start/Stop
hour used
in model
Flow
(cfs)
Fecal coliform load
(#/hr)
5/7/1999 14:00 (start) 0.00262 1.71E+10
5/7/1999 16:00 (stop)

5/15/1999 10:00 0.00036 2.38E+09
5/15/1999 16:00

10/26/1999 10:00 0.01505 9.82E+10
10/26/1999 14:00

3/24/2000 12:00 0.00518 3.38E+10
3/24/2000 13:00

9/10/2000 17:00 0.00190 1.24E+10
9/10/2000 21:00

12/21/2000 11:00 0.00836 5.45E+10
12/21/2000 12:00

2/26/2001 11:00 0.00316 2.06E+10
2/26/2001 17:00

6/5/2001 14:00 0.11140 7.27E+11
6/5/2001 15:00

6/18/2001 19:00 0.00285 1.86E+10
6/19/2001 11:00

6/23/2001 14:00 0.08569 5.59E+11
6/23/2001 15:00

7/20/2001 13:00 0.00637 4.15E+10
7/20/2001 14:00

Note: no SSOs occurred in subwatershed 8 during the model simulation period.

Final Report North Buffalo Creek Fecal Coliform TMDL A-7 Calibrated Water Quality Model Parameters
102









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Subwatershed Land use/land cover ACQOP1 SQOLIM2 IOQC/AOQC3
1 Roads (ROW) 1.37E+09 2.47E+09 16400
1 Woods 1.37E+09 2.47E+09 16400
1 Institutional 1.60E+10 2.88E+10 16400
1 Residential 9.28E+09 1.67E+10 16400
1 Industrial/Commercial 1.60E+10 2.88E+10 16400
1 Herbaceous 1.37E+09 2.47E+09 16400
2 Roads (ROW) 1.37E+09 2.47E+09 16400
2 Woods 1.37E+09 2.47E+09 16400
2 Institutional 1.60E+10 2.88E+10 16400
2 Residential 8.12E+09 1.46E+10 16400
2 Industrial/Commercial 1.60E+10 2.88E+10 16400
2 Herbaceous 1.37E+09 2.47E+09 16400
3 Roads (ROW) 1.37E+09 2.47E+09 82100
3 Woods 1.37E+09 2.47E+09 82100
3 Institutional 1.60E+10 2.88E+10 82100
3 Herbaceous 1.37E+09 2.47E+09 82100
3 Residential 9.65E+09 1.74E+10 82100
4 Roads (ROW) 1.37E+09 2.47E+09 200000
4 Woods 1.37E+09 2.47E+09 200000
4 Institutional 1.60E+10 2.88E+10 200000
4 Residential 1.51E+10 2.72E+10 200000
4 Industrial/Commercial 1.60E+10 2.88E+10 200000
4 Herbaceous 1.37E+09 2.47E+09 200000
4 Downtown 1.60E+10 2.88E+10 200000
5 Roads (ROW) 1.37E+09 2.47E+09 16400
5 Woods 1.37E+09 2.47E+09 16400
5 Institutional 1.60E+10 2.88E+10 16400
5 Industrial/Commercial 1.60E+10 2.88E+10 16400
5 Herbaceous 1.37E+09 2.47E+09 16400
5 Residential 1.20E+10 2.16E+10 16400
6.1 Roads (ROW) 1.37E+09 2.47E+09 16400
6.1 Woods 1.37E+09 2.47E+09 16400
6.1 Institutional 1.60E+10 2.88E+10 16400
6.1 Residential 8.33E+09 1.50E+10 16400
6.1 Industrial/Commercial 1.60E+10 2.88E+10 16400
6.1 MF 8.33E+09 1.50E+10 16400
6.1 Herbaceous 1.37E+09 2.47E+09 16400
6.1 Residential 8.33E+09 1.50E+10 16400
Final Report North Buffalo Creek Fecal Coliform TMDL A-7 Calibrated Water Quality Model Parameters
103
Subwatershed Land use/land cover ACQOP1 SQOLIM2 IOQC/AOQC3
6.2 Roads (ROW) 1.37E+09 2.47E+09 16400
6.2 Woods 1.37E+09 2.47E+09 16400
6.2 Institutional 1.60E+10 2.88E+10 16400
6.2 Residential 8.33E+09 1.50E+10 16400
6.2 Industrial/Commercial 1.60E+10 2.88E+10 16400
6.2 Herbaceous 1.37E+09 2.47E+09 16400
7 Roads (ROW) 1.37E+09 2.47E+09 200000
7 Woods 1.37E+09 2.47E+09 200000
7 Institutional 1.60E+10 2.88E+10 200000
7 Residential 1.19E+10 2.14E+10 200000
7 Industrial/Commercial 1.60E+10 2.88E+10 200000
7 Herbaceous 1.37E+09 2.47E+09 200000
8 Roads (ROW) 1.37E+09 2.47E+09 16400
8 Woods 1.37E+09 2.47E+09 16400
8 Industrial/Commercial 1.60E+10 2.88E+10 16400
8 Herbaceous 1.37E+09 2.47E+09 16400
1 ACQOP is the rate of accumulation of fecal coliform (#/ac-day). Rate given used for both
the pervious and impervious portions of the land cover. See Part 2 – Source Assessment
for additional details.
2 SQOLIM is the maximum storage of fecal coliform (#/ac). Rate given used for both the
pervious and impervious portions of the land cover.
3 IOQC and AOQC is the concentration of fecal coliform in interflow outflow and
groundwater outflow, respectively (#/ft3). See Part 2 – Source Assessment for additional
details.

Final Report North Buffalo Creek Fecal Coliform TMDL A-8 Calibrated Model Hydraulic Parameters
104



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Subwatershed LZSN1 INFILT2 AGWRC3 DEEPFR4 INTFW5 IRC6 LZETP7
1 10 0.06 0.99 0.1 1 0.3 0.1-0.5
2 10 0.06 0.99 0.1 1 0.3 0.1-0.5
3 10 0.06 0.99 0.1 1 0.3 0.2-0.5
4 7 0.25 0.98 0.1 1 0.3 0.1-0.7
5 6 0.16 0.98 0.1 0.75 0.5 0.1-0.7
6.1 10 0.16 0.98 0.1 1 0.3 0.3
6.2 6 0.16 0.98 0.1 0.75 0.5 0.1-0.7
7 6 0.16 0.98 0.1 0.75 0.5 0.1-0.7
8 6 0.16 0.98 0.1 0.75 0.5 0.1-0.7
1 Lower zone nominal storage (inches)
2 Soil infiltration rate (in/hr)
3 Groundwater recession rate (/day)
4 Fraction of infiltrating water which is lost to deep aquifers (no units)
5 Interflow inflow (no units)
6 Interflow recession coefficient (no units)
7 Lower zone evapotranspiration (no units)

Final Report North Buffalo Creek Fecal Coliform TMDL A-9 Greensboro’s Municipal NPDES Stormwater Permit
105



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The City of Greensboro is authorized to discharge stormwater from its Municipal Separate
Storm Sewer System (MS4) under EPA’s NPDES Phase I stormwater permit program. The
NC Division of Water Quality is the delegated permitting authority for the NPDES program.
Greensboro’s NPDES permit (NCS000248) became effective on December 30, 1994 with
the first five year term expiring on June 30, 1999. The second NPDES permit term began
on July 1, 1999 and is set to expire on June 30, 2004. The City’s NPDES stormwater
permit, and associated Stormwater Quality Management Program (SWQMP), is designed to
control the discharge of pollutants from the MS4 to the maximum extent practicable. To
meet this objective and comply with NPDES stormwater regulations, the City has developed
four major program areas as follows:

Commercial and Residential Program

Illicit Discharge and Improper Disposal Detection and Elimination Program

Industrial and Related Facilities Program, and;

Construction Site Runoff Program

Commercial and Residential Program

The focus of the Commercial and Residential Program is to develop structural and source
control measures to reduce pollutants from runoff from commercial and residential areas
that are discharged from the MS4. The program also includes development of pollutant
load reduction estimates resulting from these activities and a proposed schedule for
implementing such controls. The program is divided into six main components as
follows:

¨¨¨¨ BMP maintenance and inspections
¨¨¨¨ New development and regional master planning
¨¨¨¨ Street maintenance and operations
¨¨¨¨ Flood control structures and retrofitting
¨¨¨¨ Municipal waste management
¨¨¨¨ Pesticide, fertilizer, and herbicide management

Illicit Discharge and Improper Disposal Detection and Elimination Program

The focus of this program is to detect and remove illicit discharges into the stormwater
conveyance system. The City has developed its illicit discharge detection and elimination
program into seven categories as follows:
Final Report North Buffalo Creek Fecal Coliform TMDL A-9 Greensboro’s Municipal NPDES Stormwater Permit
106

¨¨¨¨ Establishment of legal authority
¨¨¨¨ Field screening program
¨¨¨¨ Follow-up investigation program
¨¨¨¨ Spill response program
¨¨¨¨ Public reporting program
¨¨¨¨ Used oil and household hazardous waste program
¨¨¨¨ Sanitary waste management program

Industrial and Related Facilities Program

The focus of this program is to monitor and control pollutants in stormwater discharges
from municipal landfills, hazardous waste treatment, disposal, and recovery facilities,
industrial facilities that are subject to section 313 of title III of the Superfund
Amendments and Reauthorization Act of 1986 (SARA), and industrial facilities that are
contributing a substantial pollutant loading to the MS4. The industrial and related
facilities program is divided into two main components as follows:

¨¨¨¨ Inspections, control, and training
¨¨¨¨ Monitoring

Construction Site Runoff Program

The focus of this program is to implement and maintain structural and non-structural
BMPs to reduce pollutants in stormwater runoff from construction sites to the MS4. The
construction site runoff program is divided into four main components as follows:

¨¨¨¨ Site planning
¨¨¨¨ BMP requirements
¨¨¨¨ Site inspections and enforcement
¨¨¨¨ Site operator education

Implementation of Greensboro’s NPDES Phase I permit is supported by a Stormwater
Utility funding mechanism which ensures a dedicated source of revenue for the
aforementioned programs and activities. More information about the City’s Stormwater
Management Program can be found at the following web address:

http://www.ci.greensboro.nc.us/stormwater/
Final Report North Buffalo Creek Fecal Coliform TMDL A-10 Public Notification of North Buffalo Creek Fecal Coliform TMDL
107



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Now Available Upon Request

Fecal Coliform
Total Maximum Daily Load
North Buffalo Creek
Public Review Draft – January 2004

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 the pollutants, determines allowable
loads to surface waters, and suggests pollutant allocations.

TO OBTAIN A FREE COPY OF THE TMDL REPORTS:

Please contact Ms. Robin Markham [phone], extension 558 or write to:
Adugna Kebede
Water Quality Planning Branch
NC Division of Water Quality
1617 Mail Service Center
Raleigh, NC 27699-1617

The draft TMDL is also located on the following website: http://h2o.enr.state.nc.us/tmdl.
Interested parties are invited to comment on the draft TMDL study by February 13, 2004.
Comments concerning the report should be directed to the Division of Water Quality at
the above address.

Public Meeting Notice
A public meeting to discuss the TMDL will be held on
January 29 at 9 AM at the following address:
CITY OF GREENSBORO WATER RESOURCES DEPARTMENT
201 North Green Street (2nd floor), NC 27402
Phone: [phone]

Final Report North Buffalo Creek Fecal Coliform TMDL A-10 Public Notification of North Buffalo Creek Fecal Coliform TMDL
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