JordanLakeTMDLFinal

B. Everett Jordan Reservoir, North Carolina Phase I
Total Maximum Daily Load

Final Report
September 2007

(EPA Approval Date: September 20, 2007)

Prepared by:
NC Department of Environment
And Natural Resources
Division of Water Quality
1617 Mail Service Center
Raleigh, NC 27699-1617
[phone]
Cape Fear River Basin
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Executive summary

The B. Everett Jordan Reservoir (Jordan Reservoir) Total Maximum Daily Load was developed to
satisfy state Nutrient Sensitive Water (NSW) requirements and a federally-mandated TMDL. Both
the NSW and TMDL programs include the development of a calibrated nutrient response model to
support a management strategy to control nutrients and meet the state chlorophyll a standard.

Jordan Reservoir is a multi-use impoundment operated by the U.S. Army Corps of Engineers. The
reservoir was formed with the construction of a dam on the Haw River in the Cape Fear River
Basin. The lake covers an area of 13,940 acres at elevation 216 feet msl, the normal operating
level. The lake is operated for flood control, water quality (low flow augmentation), fish and
wildlife conservation, recreation, and water supply. Jordan Reservoir consists of two distinct arms
- the Haw River and New Hope Creek arms. The Haw River Arm of the lake has an average
hydraulic retention time of five days and accounts for 70 to 90 percent of the annual flow through
Jordan Reservoir. The New Hope Creek Arm of the lake has an average hydraulic retention time of
418 days. The Jordan Reservoir watershed encompasses 1,686 square miles and includes parts of
Alamance, Caswell, Chatham, Durham, Forsyth, Guilford, Orange, Randolph, Rockingham, and
Wake counties. It includes all or portions of the urban areas of Durham, Chapel Hill, Cary,
Burlington, Greensboro, and several other small municipalities.

The Clean Water Responsibility Act of 1997 (often referred to as House Bill 515) included
legislation to further address water quality problems in NSW waters (NC General Statute 143-
215.1(c1) to (c5)). The act set total nitrogen (TN) and total phosphorus (TP) NPDES permit limits
for facilities discharging greater than 0.5 MGD into the Jordan Reservoir/Haw River watershed. A
5-year compliance period for limits of 5.5 mg/L of TN and 2.0 mg/L of TP was established for
qualifying wastewater facilities. The act also established that a calibrated nutrient response model
may be developed by DWQ in conjunction with affected parties, and the model may indicate the
required TN and TP concentration limits for dischargers greater than 0.5 MGD are different from
those listed above. In 1998, Senate Bill 1366 allowed the Environmental Management
Commission (EMC) to extend the compliance deadline for these dischargers if additional time was
needed to develop a calibrated nutrient response model. The municipalities of Greensboro,
Mebane, Reidsville, Graham, Pittsboro, and Burlington, and the Orange Water and Sewer
Authority (OWASA) were granted a compliance extension in 1999. Facilities that did not seek
compliance extensions were the City of Durham/Durham South WWTP and the Durham County/
Triangle WWTP. Conditions associated with the extended compliance period were achieved and
the calibrated nutrient response model was accepted by the Water Quality Committee (WQC) of
the EMC in July 2002.

The nutrient response model predicted a high frequency of violations of the chlorophyll a standard
in the management area representing the Upper New Hope Arm of Jordan Reservoir. This
management area corresponds to that portion of the lake upstream of SR 1008. As a result of this
model prediction, the Upper New Hope Arm of Jordan Reservoir was placed on the 2002 303(d)
List of impaired waters. The Lower New Hope Arm and the Haw River Arm were later placed on
the 303(d) List of impaired waters in 2006 for chlorophyll a impairment. The Clean Water Act
(CWA) requires that a Total Maximum Daily Load (TMDL) be developed for each of the waters
appearing on the 303(d) list. The objective of a TMDL is to estimate the allowable pollutant loads
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and allocate the loads to known sources so that the waterbody may be restored to its intended uses.
All TMDLs must be approved by the US Environmental Protection Agency (EPA). This document
represents Phase I of the Jordan Reservoir TMDL. The Haw River arm of the reservoir was listed
as impaired for elevated pH on the 2006 303(d) list of impaired waters. Phase II of this TMDL will
address the pH impairment of the Haw River arm. Like chlorophyll a, elevated pH is a symptom of
excessive nutrient loading to the lake.

Jordan Reservoir has historically been one of the most eutrophic reservoirs in North Carolina.
Excursions of the state water quality standard for chlorophyll a have been noted frequently,
especially in the Upper New Hope Arm. Nutrients from a variety of point and nonpoint sources
reach Jordan Reservoir. Point sources as a whole contributed an average of 1.5 million pounds of
nitrogen and 140 thousand pounds of phosphorus to the reservoir each year. Nonpoint sources
contributed an average of 2.5 million pounds of nitrogen and 350 thousand pounds of phosphorus
per year.

Through the combined efforts of the facilities that were granted the compliance extension and the
Division of Water Quality, multiple modeling tools were developed to evaluate conditions in the
reservoir and potential management strategies for the reservoir. This includes the development of a
calibrated hydrodynamic and nutrient response model for the years 1997 through 2001, an effluent
nutrient delivery model, a nutrient fate and transport model, and a watershed loading model. The
management strategies were determined through multiple runs of the nutrient response model with
a variety of reduction strategies for both total nitrogen and total phosphorus. For each run of the
nutrient response model, the frequency of violation of the chlorophyll a standard was evaluated for
the entire modeled period (1997 - 2001) and for critical conditions during the summer months.
Critical conditions were defined as May through September based on the model results and the
measured data. The two distinct arms of the lake, the Haw River and New Hope Creek arms, were
each evaluated separately. Further, the New Hope Creek arm was separated into the Upper New
Hope Arm and the Lower New Hope Arm. The split between these two areas is SR 1008.
Reduction targets were evaluated in terms of nitrogen and phosphorus loads. Multiple
combinations of nitrogen and phosphorus loading scenarios that resulted in an 8% standard
violation frequency were considered. Ultimately, three different targets were selected for Jordan
Reservoir corresponding to the different areas of the reservoir.

Nutrient load reduction targets from 1997-2001 baseline
Area Total nitrogen (TN)
percent reduction
Total phosphorus
(TP) percent
reduction
Upper New Hope Arm (above SR1008) 35% 5%
Lower New Hope Arm (from SR1008 to the
narrows)
N/A (a) N/A (a)
Haw River Arm 8% 5%
(a) Provides a loading cap equal to 1997-2001 baseline nutrient loads.

Both point and nonpoint sources bear an equal burden for nutrient reductions. For example, point
sources in the Upper New Hope Arm of Jordan Reservoir must reduce nitrogen loads by 35% and
nonpoint sources in the Upper New Hope Arm of Jordan Reservoir must reduce nitrogen loads by
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35%. In this manner, the burden for reductions resulting from the nutrient management strategy is
equally borne by point and nonpoint sources.

Point Source Strategy.
Upper New Hope Arm of Jordan Reservoir. All of the available loading was allocated to the
existing facilities. Therefore, there will be no new nitrogen or phosphorus bearing loads permitted
in this watershed. There are four facilities discharging greater than 100,000 gallons per day in the
watershed of the Upper New Hope Arm. These facilities account for 99.7% of the total permitted
flow from point sources. The discharge allocations for these four facilities provide equivalent
concentrations for each facility. For nitrogen, this equivalent concentration is 3.04 mg/L, and for
phosphorus this equivalent is 0.23 mg/L.

Haw River Arm of Jordan Reservoir. All of the available loading was allocated to the existing
facilities. Therefore, there will be no new nitrogen or phosphorus bearing loads permitted in this
watershed. There are ten facilities discharging greater than 100,000 gallons per day in watershed of
the Haw River Arm. These facilities account for 99.3% of the total permitted flow from point
sources. The discharge allocations for these ten facilities provide equivalent treatment levels for
each facility. For nitrogen, this equivalent treatment level is 5.3 mg/L, and for phosphorus this
equivalent is 0.67 mg/L

Nonpoint Source Strategy
The NPS management strategy proposed by DWQ staff builds on concepts implemented in the
Neuse and Tar-Pamlico River Basins. All of the following elements would apply in the
subwatersheds of both the Upper New Hope and Haw River arms, while only the riparian buffer
protection and new development controls - would apply in the Lower New Hope subwatershed.
The proposed strategy would require that:
• All agricultural operations would collectively meet N and P export performance goals as
implemented by local committees (EMC has no regulatory authority over this management
area);
• Stormwater:
o New development in unincorporated areas of all counties except Caswell and
Rockingham are subject to the post-construction stormwater measure of the NPDES
Phase II requirements and are permitted by DWQ beginning July 1, 2007
o Seventeen of the twenty six municipalities in the watershed were issued permits by
December 2005 to implement all six measures of the Phase II requirements, either
alone or as part of another MS4's permit, and were required to begin implementing
post-construction permitting under those permits by December 2007
o All local governments would achieve stormwater N and P export performance goals
from all new and existing development;
• DWQ would require local governments to protect riparian buffers;
• Persons who apply fertilizers to lands in the subwatershed would complete nutrient
management training and a written plan for those lands. A tax on fertilizer would fund the
implementation of this rule;
• DWQ would work with DEH to develop programs to reduce N and P loading from on-site
wastewater (the EMC has no control over this management area);
• DWQ would refine existing wastewater land application permitting programs as needed;
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• DWQ would establish a trading program between point and nonpoint sources and among
nonpoint sources; and
• Local governments and agricultural committees would provide annual reports to the EMC.
The EMC would reexamine the management strategy every five years.

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Table of Contents

1 Introduction................................................................................................................................. 1
2 Nutrient Sensitive Waters Management ..................................................................................... 2
3 TMDL Process............................................................................................................................ 4
3.1 Reservoir and Watershed Description ................................................................................ 6
3.2 Water Quality Target .......................................................................................................... 9
3.3 Water Quality Assessment................................................................................................ 10
4 Source Assessment ................................................................................................................... 17
4.1 Point Source Assessment.................................................................................................. 17
4.2 Non-Point Source Assessment.......................................................................................... 22
5 Modeling Approach.................................................................................................................. 24
5.1 Jordan Reservoir Response Model Enhancement - Summary.......................................... 25
5.2 Watershed Model Development - Summary .................................................................... 34
6 Reduction Targets..................................................................................................................... 40
6.1 Total Maximum Daily Load (TMDL) .............................................................................. 40
6.2 Model Scenarios ............................................................................................................... 40
6.3 Critical Conditions............................................................................................................ 44
6.4 Seasonal Variation............................................................................................................ 44
6.5 Attainment of other Water Quality Standards .................................................................. 44
6.6 Model Uncertainty and Margin of Safety......................................................................... 45
6.7 Blue Green Algae.............................................................................................................. 47
7 Allocations................................................................................................................................ 49
7.1 Wasteload Allocations...................................................................................................... 50
7.2 Load Allocations............................................................................................................... 53
8 Future Efforts............................................................................................................................ 55
9 References................................................................................................................................. 57
Appendix I. Supporting documents for the Jordan Reservoir Phase I TMDL ..............................A-1
Appendix II. EPA letter to DWQ dated November 23, 2003........................................................A-2
Appendix III. Volume-weighted statistics for the Jordan Reservoir nutrient response model......A-4
Appendix IV. TMDL summary sheet............................................................................................A-6
Appendix V. WLA calculations for the Upper New Hope and Haw River Management Areas A-10
Appendix VI. DWQ responsiveness summary for public comments on the Jordan Reservoir Phase
I TMDL.........................................................................................................................................A-13

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List of Tables

Table 1. Total watershed areas for Jordan Reservoir by lake management area ..............................7
Table 2. Summary statistics for nutrients (mg/L) and chlorophyll a (ug/L) at selected
stations in Jordan Reservoir (1990 – 2003). Data for Lower Hope Arm Stations
CPF087D and CPF08801A are not shown because those stations were not
monitored continuously during these time periods. Chlorophyll a data from 9/96 –
1/01 are uncorrected for phaeophytin concentrations............................................................16
Table 3. Continuous point source dischargers in the Upper New Hope Arm watershed of
Jordan Reservoir ....................................................................................................................17
Table 4. Continuous point source dischargers in the Haw River Arm watershed of Jordan
Reservoir................................................................................................................................18
Table 5. Stormwater MS4 permits in the watershed of Jordan Reservoir ........................................22
Table 6. Nutrient load delivered to the Upper New Hope Arm of Jordan Reservoir by
continuous NPDES dischargers.............................................................................................30
Table 7. Nutrient load delivered to the Haw River Arm of Jordan Reservoir by continuous
NPDES dischargers................................................................................................................31
Table 8. Existing nutrient loads to Jordan Reservoir (1997-2001 average in lbs/yr) .......................33
Table 9. Summary of average annual field-scale loading rates by land use across all HRUs
(lbs/ac/yr)...............................................................................................................................36
Table 10. Distribution of point and nonpoint source nutrient load delivered to Jordan
Reservoir, by county..............................................................................................................38
Table 11. Long-term average proportions of point and nonpoint source loads in the Jordan
Reservoir watershed...............................................................................................................39
Table 12. Loading targets for the Jordan Reservoir management areas ...........................................44
Table 13. Wasteload and load allocations for the three management areas of Jordan
Reservoir................................................................................................................................50

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List of Figures

Figure 1. Location map for Jordan Reservoir ...................................................................................6
Figure 2. Jordan Reservoir management areas .................................................................................8
Figure 3. Distribution of land uses across the Jordan Reservoir watershed .....................................9
Figure 4. Jordan Reservoir sampling stations...................................................................................12
Figure 5. Chlorophyll a concentrations collected by DWQ for 1990 - 2003 at three stations,
CPF086F, CPF086C, and CPF081A1C, in the Upper New Hope Arm of Jordan
Reservoir. Data from 9/96 – 1/01 are uncorrected concentrations. ......................................13
Figure 6. Chlorophyll a concentrations collected by DWQ for 1990 - 2003 at three stations,
CPF087B3, CPF087D, and CPF08801A, in the Lower New Hope Arm of Jordan
Reservoir. Data from 9/96 – 1/01 are uncorrected concentrations. ......................................14
Figure 7. Chlorophyll a concentrations collected by DWQ for 1990 - 2003 at two stations,
CPF055C and CPF055E, in the Haw River Arm of Jordan Reservoir. Data from
9/96 – 1/01 are uncorrected concentrations. ..........................................................................15
Figure 8. Locations of NPDES wastewater permits, NPDES stormwater permits, and
certified confined animal operations in the Jordan Reservoir watershed ..............................21
Figure 9. WASP model surface segments for Jordan Reservoir (outline at flood pool
elevation) ...............................................................................................................................26
Figure 10. Simulated chlorophyll a concentrations (average) and frequency of
concentrations greater than 40 ug/L for Jordan Reservoir, 1997-2001..................................28
Figure 11. Sources of nitrogen (left panel) and phosphorus (right panel) nonpoint source
loading to Jordan Reservoir in the Upper New Hope Arm....................................................37
Figure 12. Volume-weighted aggregate responses to Jordan Reservoir load reductions in
the Upper New Hope Arm.....................................................................................................42
Figure 13. Volume-weighted aggregate responses to Jordan Reservoir load reductions in
the Haw River Arm................................................................................................................43

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1 Introduction

This Total Maximum Daily Load (TMDL) was prepared by the NC Division of Water Quality to
evaluate the protection and maintenance of the chlorophyll a standard within B. Everett Jordan
Reservoir. This reservoir nutrient management strategy is unusual in that both a state-mandated
nutrient management strategy and a federally-mandated TMDL were needed for the same
waterbody. Although both programs have similar goals, the methodology for reaching those goals
can be dissimilar. The strategy described herein was developed to meet the goals and methodology
of both programs in order to provide non-conflicting recommendations for controlling nutrient-
related issues.

The results of this strategy represent many years of work and collaboration between many parties.
The first Request for Proposals for nutrient modeling and evaluation was issued in 1999 and
technical work continued throughout 2004. Specifics of the NSW process are provided below in
Section 2. Subsequent placement of the Upper New Hope Arm of B. Everett Jordan Reservoir on
the North Carolina 2002 303(d) List and the Lower New Hope and Haw River Arms on the 2006
303(d) list required a TMDL to be developed for the lake. The NSW process, which preceded the
TMDL process by several years, is described in Section 2. The TMDL process is described in
Section 3.

This is a phased TMDL in that some of the wasteload allocations proposed in this document (i.e.
phosphorus) will be implemented in the next permit cycle for facilities discharging in the Jordan
reservoir. Wasteload allocations for nitrogen will be implemented in a second phase of the TMDL.
Load allocations for nonpoint sources will be implemented as dictated by rules developed in the
nutrient management strategy.

The Jordan Lake (Reservoir) Stakeholder Process began in 2003 in order to engage interested
stakeholders in the development of a nutrient management strategy that could be presented to the
North Carolina Environmental Management Commission. Through this process, approximately
113 stakeholder organizations, including the Division of Water Quality, developed
recommendations for the nutrient management strategy and TMDL. A complete description of the
meetings, discussion topics, and recommendations can be found at
http://www.tjcog.dst.nc.us/jorlak/jlsp.htm.

All documentation supporting this nutrient management strategy can be found on the worldwide
web at the following addresses:
Triangle J Council of Governments, Jordan Lake Stakeholder Project
http://www.tjcog.dst.nc.us/jorlak/jlsp.htm
Triangle J. Council of Governments, Jordan Lake Nutrient Response Modeling Project
http://www.tjcog.dst.nc.us/jorlak/index.htm
NC Division of Water Quality, Special Studies, Jordan Lake
http://h2o.enr.state.nc.us/tmdl/SpecialStudies.htm#Jordan

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2 Nutrient Sensitive Waters Management

In 1983, all waters in the Haw River watershed (subbasins 030601 to 030606), including B. Everett
Jordan Reservoir (Jordan Reservoir) received a supplemental classification of nutrient sensitive
water (NSW). This supplemental classification acknowledges that Jordan Reservoir could have
water quality problems associated with excessive nutrient inputs from both wastewater discharges
and runoff from the various land uses in the watershed. The supplemental classification requires
that a NSW strategy be created and implemented to protect the reservoir from water quality
problems associated with nutrient enrichment. As a result, total phosphorus (TP) limits of 2.0
mg/L were required for NPDES permitted wastewater facilities with permitted flows greater than
0.005 MGD. Due to special concerns in the Upper New Hope Arm of the reservoir, NPDES
permitted wastewater facilities received TP limits of 0.5 mg/L during the months from April to
October. However, nuisance algal blooms and chlorophyll a levels exceeding water quality
standards continue to be observed.

The Clean Water Responsibility Act of 1997 (CWRA, often referred to as House Bill 515) included
legislation to further address water quality problems in NSW waters (NC General Statute 143-
215.1(c1) to (c5)). The act set total nitrogen (TN) and total phosphorus (TP) NPDES permit limits
for facilities discharging greater than 0.5 MGD into the Jordan Reservoir/Haw River watershed. A
5-year compliance period for limits of 5.5 mg/L of TN and 2.0 mg/L of TP was established for
qualifying wastewater facilities. The act also established that a calibrated nutrient response model
may be developed by DWQ in conjunction with affected parties, and the model may indicate the
required TN and TP concentration limits for dischargers greater than 0.5 MGD are different from
those listed above. Amendments to the act approved in 1998 (referred to as Senate Bill 1366)
provided a compliance extension to the nutrient limits, with conditions. Those wastewater facilities
granted a compliance extension by the Environmental Management Commission were required to
develop a calibrated nutrient response model, evaluate and optimize the operation of all facilities to
reduce nutrient loading, and evaluate methods to reduce nutrient mass loading to NSW waters. The
municipalities of Greensboro, Mebane, Reidsville, Graham, Pittsboro, and Burlington, and the
Orange Water and Sewer Authority (OWASA) were granted the compliance extension by the
Environmental Management Commission in April 1999. This collective group is referred to as the
Project Partners in subsequent chapters. Facilities that did not seek compliance extensions are the
City of Durham/ Durham South WWTP and Durham County/ Triangle WWTP.

The CWRA provided a timeline for progress towards a site-specific nutrient management strategy
should facilities and/or municipalities choose to seek the compliance extension. This established
timeline is as follows:
• Two years for the collection of data needed to prepare a calibrated nutrient response model;
• A maximum of one year to prepare the calibrated nutrient response model;
• The amount of time, if any, that is required for the Commission to develop a nutrient
management strategy and to adopt rules or to modify discharge permits to establish
maximum mass loads or concentration limits based on the calibrated nutrient response
model; and
• A maximum of three years to plan, design, finance, and construct a facility that will comply
with those maximum mass loads and concentration limits.
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If the Commission finds that additional time is needed to complete the construction of a facility, the
Commission may further extend the compliance date by a maximum of two additional years.

Each municipality developed optimization plans and submitted summaries at the July 2000 Water
Quality Committee meeting. Plans for the nutrient response model development began in 1999
when the Project Partners, through the local councils of governments, released a request for
proposals for both a data review document and nutrient response model development. Screening
level and detailed nutrient response models, and an effluent nutrient delivery model, were
developed by consultants, Tetra Tech, Inc. and subcontractors. The total cost to the project
partners for the development of the data review document and the models was $370,000. The
combined hydrodynamic and water quality model was approved by the Water Quality Committee
in July 2002.

The Upper New Hope Arm of B. Everett Jordan Reservoir was placed on the 2002 303(d) list of
impaired waters based on results of the nutrient response model and the approval of the model by
the Water Quality Committee. The listing of the Upper New Hope Arm is consistent with EPA
rules that allow water quality models to be utilized as a basis for 303(d) listing. The Lower New
Hope Arm and Haw River Arms were listed on the 2006 303(d) list. The 303(d) listing of the
reservoir resulted in the need for a TMDL for the lake. Thus, the Jordan Reservoir nutrient
management strategy was developed in order to meet requirements of both the Clean Water
Responsibility Act and the federal rules and guidance regarding TMDLs.

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3 TMDL Process

The B. Everett Jordan Reservoir (Jordan Reservoir) is currently on the 303(d) list of impaired
waters in North Carolina (NC). The 303(d) list is developed biennially pursuant to 40CFR130.7.
The NC Division of Water Quality (DWQ) has identified all management areas of Jordan Reservoir
in the Cape Fear River Basin as impaired by chlorophyll a.

Section 303(d) of the Clean Water Act (CWA) requires states to develop a list of waters not
meeting water quality standards or which have impaired uses. This list, referred to as the 303(d)
list, is submitted biennially to the U.S. Environmental Protection Agency (EPA) for review.

The 303(d) process requires that a Total Maximum Daily Load (TMDL) be developed for each of
the waters appearing on Part I of the 303(d) list. The objective of a TMDL is to estimate allowable
pollutant loads and allocate the loads to known sources so that actions may be taken to restore the
water to its intended uses (USEPA, 1991). Generally, the primary components of a TMDL, as
identified by EPA (1991, 2000a) and the Federal Advisory Committee (FACA, 1998) are as
follows:

Target identification or selection of pollutant(s) and end-point(s) for consideration. The pollutant
and end-point are generally associated with measurable water quality related characteristics that
indicate compliance with water quality standards. North Carolina indicates known pollutants on
the 303(d) list.

Source assessment. All sources that contribute to the impairment should be identified and loads
quantified, where sufficient data exist.

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

Allocation of pollutant loads. Allocating pollutant control responsibility to the sources of
impairment. The wasteload allocation portion of the TMDL accounts for the loads associated with
existing and future point sources including NPDES-permitted stormwater. Similarly, the load
allocation portion of the TMDL accounts for the loads associated with existing and future non-
point sources, non-NPDES stormwater, and natural background sources.

Margin of Safety. The margin of safety addresses uncertainties associated with pollutant loads,
modeling techniques, and data collection. Per EPA (2000a), the margin of safety may be expressed
explicitly as unallocated assimilative capacity or implicitly due to conservative assumptions.

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

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Critical Conditions. Critical conditions indicate the combination of environmental factors that
result in just meeting the water quality criterion and have an acceptably low frequency of
occurrence.

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

The goal of the TMDL program is to restore designated uses to water bodies. Thus, the
implementation of source controls throughout the watershed will be necessary to restore uses in
Jordan Reservoir. An implementation plan is included as part of the combined nutrient
management strategy and TMDL document. Per TMDL program guidance, individual NPDES
wasteload allocations are provided for continuously discharging facilities subject to this TMDL.
NPDES stormwater wasteload allocations are not provided separately, but are included in the
overall nonpoint source reduction target. The nutrient management strategy provided herein
includes a majority of nonpoint sources, including NPDES stormwater, septic systems, and non-
discharge systems.
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3.1 Reservoir and Watershed Description

Jordan Reservoir is a multi-use impoundment operated by the U.S. Army Corps of Engineers and
located on Haw River and New Hope Creek, Cape Fear River Basin, in the eastern Piedmont region
of North Carolina (Figure 1). The length of the shoreline is approximately 200 miles. The lake
covers an area of 13,940 acres at elevation 216 feet msl, which is at the top of the conservation
pool and the normal operating level. The lake, impounded in 1982, is operated for flood control,
water quality (low flow augmentation), fish and wildlife conservation, recreation, and water supply
(PL 88-253). It has an estimated water supply yield of 100 million gallons per day, and currently
serves as a regional source of drinking water supply.

Jordan Reservoir consists of two distinct arms - the Haw River arm and the New Hope arm. Major
inflows are the Haw River and New Hope and Morgan Creeks. The Haw River arm of the lake has
an average hydraulic retention time of five days and accounts for 70 to 90 percent of the annual
flow through Jordan Reservoir. The New Hope Creek arm of the lake has an average hydraulic
retention time of 418 days. Maximum depth of the lake is approximately 66 feet (20 meters) with a
mean depth of five meters and a total volume of 265 million cubic meters.

Figure 1. Location map for Jordan Reservoir.

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Surface water classifications are designations applied to surface water bodies that define the best
uses to be protected within these waters (e.g., swimming, fishing, and drinking water supply) and
carry with them an associated set of water quality standards to protect those uses. The New Hope
Creek Arm of Jordan Reservoir is classified as a WS-IV B NSW CA. The Haw River Arm of
Jordan Reservoir is classified as WS-IV NSW CA. Combined, the waters of the reservoir are
protected for water supply, primary and secondary recreation, fishing, wildlife, fish and aquatic life
propagation and survival, agriculture and other uses suitable for Class C. Jordan Reservoir was
designated as a Nutrient Sensitive Water (NSW) in 1983.

The Jordan Reservoir watershed encompasses 1,686 square miles (excluding the lake itself) and
includes parts of Alamance, Caswell, Chatham, Durham, Forsyth, Guilford, Orange, Randolph,
Rockingham, and Wake counties. It includes some or all of the urban areas of Durham, Chapel
Hill, Cary, Burlington, Greensboro, and several other small municipalities. For the purposes of this
TMDL, the reservoir was divided into management areas as shown in figure 2. The drainage areas
for the three TMDL management areas are shown in Table 1.

Table 1. Total watershed areas for Jordan Reservoir by lake management area
Lake management area Acres Percent
Haw River Arm 859,442 79.65%
Upper New Hope (River) Arm 148,146 13.73%
Lower New Hope (River) Arm 71,437 6.62%
Total watershed area 1,079,026 100%

An improved land use database was created consisting of the 1992 National Land Cover Database
(NLCD) from the Multi-Resolution Land Characterization (MRLC) Consortium, updated in
Orange, Durham, Chatham, and Wake counties using current tax parcel information, and updated
in all other areas for residential density using the 2000 Census (Tetra Tech, 2003b). This yields a
near-current estimate of land use in the basin, with the primary exception that
commercial/industrial development in the Haw River basin that occurred after the date of the
NLCD. A summary provided in Figure 3 indicates approximately 18% urban, 20% agriculture, and
56% forest in the Jordan Reservoir watershed.

The Jordan Reservoir watershed lies primarily within the Carolina Slate Belt and Triassic Basins.
The Carolina Slate Belt consists of heated and deformed volcanic and sedimentary rocks. Soils in
the belt have high silt content and overlie thin saprolite. The major soils are Georgeville, Badin,
and Tatum. Streams within the belt have narrow valleys and flood plains that widen abruptly upon
entering the Triassic basin (Daniels et al., 1999). The Triassic basins are filled with sedimentary
rocks that formed about 190-200 million years ago. Mayodan, Creedmor, and White Store soils
occupy the largest area of the basin. Upper portions of the Haw River Arm are located in the
Milton Belt and the Charlotte Belt.

B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 8

Figure 2. Jordan Reservoir management areas.
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 9

Figure 3. Distribution of land uses across the Jordan Reservoir watershed.

3.2 Water Quality Target

The North Carolina fresh water quality standard for chlorophyll a in Class C waters (T15A:
02B.0211) states the following: not greater than 40 µg/l for lakes, reservoirs, and other waters
subject to growths of macroscopic or microscopic vegetation not designated as trout waters, and
not greater than 15 µg/l for lakes, reservoirs, and other waters subject to growths of macroscopic or
microscopic vegetation designated as trout waters (not applicable to lakes and reservoirs less than
10 acres in surface area).

MultiFamily
Residential
1%
Commercial/
Industrial
3%
Single Family
Residential
14%
Forest
56%
Other
6%
Agriculture
20%
MultiFamily
Residential
1%
Commercial/
Industrial
2%
Single Family
Residential
14%
Forest
55%
Other
4%
Agriculture
24%
MultiFamily
Residential
5%
Commercial/
Industrial
6%
Single Family
Residential
16%
Forest
59%
Other
10%
Agriculture
4%
Entire Watershed
Haw River Drainage Upper New Hope Drainage
MultiFamily
Residential
1%
Commercial/
Industrial
3%
Single Family
Residential
14%
Forest
56%
Other
6%
Agriculture
20%
MultiFamily
Residential
1%
Commercial/
Industrial
2%
Single Family
Residential
14%
Forest
55%
Other
4%
Agriculture
24%
MultiFamily
Residential
5%
Commercial/
Industrial
6%
Single Family
Residential
16%
Forest
59%
Other
10%
Agriculture
4%
Entire Watershed
Haw River Drainage Upper New Hope Drainage
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 10
Chlorophyll a is the endpoint for this nutrient management strategy and TMDL. The target is
based on the chlorophyll a criterion of 40 µg/L: DWQ seeks to have less than a 10% violation
frequency (excluding the margin of safety) of that criterion during the critical period where algal
growth is highest, defined for this application as May through September. The application of the
standard in this manner is supported by EPA Region 4 (Appendix II).

Algal growth is affected by numerous biotic and abiotic factors including light availability, flow
and water velocity, nutrients (particularly nitrogen and phosphorus), grazing, and other influences.
Nutrient controls are the most common focus of management schemes for reducing excessive algal
growth and chlorophyll a concentrations. Therefore, the TMDL will be written for total nitrogen
(TN) and total phosphorus (TP) loads to the lake.

The instream numeric target, or endpoint, is the restoration objective associated with implementing
the specified nutrient load reductions in the TMDL. The target allows for the evaluation of
progress towards the goal of reaching water quality standards for the impaired stream by comparing
the instream data to the target.

3.3 Water Quality Assessment

Since the reservoir was impounded in 1982, it has been monitored extensively. Monitoring on the
lake over the years has been performed by DWQ, Town of Cary, City of Durham, Orange Water
and Sewer Authority, Town of Pittsboro, Durham County, the U.S. Geological Survey, and UNC-
Chapel Hill.

In addition to historical sampling of the lake since July of 1982, the lake was sampled monthly by
DWQ during the summer in 1996 through 1999. During 2000 and 2001, sampling was conducted
twice per month during May through August, and monthly during cooler periods. The locations of
sampling stations are provided in Figure 4.

Jordan Reservoir has historically been one of the most eutrophic reservoirs in North Carolina.
Excursions of the state water quality standard for chlorophyll a have been noted frequently as
evidenced in Figures 5, 6, and 7, especially in the Upper New Hope Arm. Nutrient concentrations
in the lake are also high (Table 2). The elevated nutrient concentrations result from a combination
of point and nonpoint source loads.

A detailed presentation and summary of historical data from 1982 through 1999 can be found in
Tetra Tech (2001). The document also summarizes past research on the lake. Key results from the
evaluation of existing data include the following:

• Jordan Reservoir is eutrophic, with high algal productivity, especially in the upstream ends
of the New Hope and Haw River arms.
• Conditions in the lake appear to have improved somewhat from lake startup until the early
1990's, but have shown little change since that time.
• Excessive algal growth in the lake is supported by high levels of nutrient input and
recycling.
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 11
• Several lines of evidence, including an initial BATHTUB scoping model, N:P ratio, and
algal growth potential tests, suggest that algal response in the lake is sensitive to nitrogen
loading, with less sensitivity to phosphorus loading.
• Nonalgal turbidity and consequent reduction in light penetration plays an important role in
controlling algal growth in the lake.
• Nutrient cycling in the lake is complex, with strong feedback between algal populations and
concentrations of nutrient species. Algal biomass is sufficiently high that dissolved
inorganic forms of nutrients are rapidly scavenged from the water column during the
summer months.
• Algal response to nutrient loads differs among taxonomic groups. In particular, blue green
algae (Cyanophytes) have a high correlation with summer nuisance conditions, but show a
negative correlation with nitrate-plus-nitrite nitrogen concentration.
• Because of the complex responses of different algal groups to nutrient loads, chlorophyll a
concentrations provide only an approximate and rough indicator of responses that may
degrade or impair uses of the lake.
• Mixing patterns in the lake are complex, and involve exchanges between the Haw River and
New Hope arms. These two management areas have very different hydraulic characteristics
and residence times, and may exhibit qualitatively different responses to changes in nutrient
loads.
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 12

Figure 4. Jordan Reservoir sampling stations.
CPF086C
CPF087D
CPF087B3
CPF087B CPF086F
CPF081A1C
CPF0880A
(2000 - 2001 Study)
CPF08801A
CPF055C
CPF0884A
CPF055E
2000 - 2001 DWQ Stations
CPF049
CPF050
BYNUM
U.S.15-501
U.S.64
B. Everett Jordan Lake
DWQ Sampling Stations
N
MorganCreek
New
HopeCreek
Jordan Lake Dam
Haw River
SR1008
New Hope River arm
a b
a b c d
CPF081A1CUPS
CPF086CUPS
CPF0880A
(historical)e
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 13

CPF086F
0
20
40
60
80
100
120
140
160
Jan-90
Jan-91
Jan-92
Jan-93
Jan-94
Jan-95
Jan-96
Jan-97
Jan-98
Jan-99
Jan-00
Jan-01
Jan-02
Jan-03
ch
l

a

(
m
i
c
r
o
g
r
a
m
s

p
e
r

l
i
t
e
r
)

CPF086C
0
20
40
60
80
100
120
140
160
Jan-90
Jan-91
Jan-92
Jan-93
Jan-94
Jan-95
Jan-96
Jan-97
Jan-98
Jan-99
Jan-00
Jan-01
Jan-02
Jan-03
ch
l

a

(
m
i
c
r
o
g
r
a
m
s

p
e
r

l
i
t
e
r
)

CPF081A1C
0
20
40
60
80
100
120
140
160
Jan-90
Jan-91
Jan-92
Jan-93
Jan-94
Jan-95
Jan-96
Jan-97
Jan-98
Jan-99
Jan-00
Jan-01
Jan-02
Jan-03
ch
l

a

(
m
i
c
r
o
g
r
a
m
s

p
e
r

l
i
t
e
r
)

Figure 5: Chlorophyll a concentrations collected by DWQ for 1990 - 2003 at three stations,
CPF086F, CPF086C, and CPF081A1C, in the Upper New Hope Arm of Jordan Reservoir. Data
from 9/96 - 1/01 are uncorrected concentrations.
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 14

CPF087B3
0
20
40
60
80
100
120
140
160
Jan-90
Jan-91
Jan-92
Jan-93
Jan-94
Jan-95
Jan-96
Jan-97
Jan-98
Jan-99
Jan-00
Jan-01
Jan-02
Jan-03
ch
l

a

(
m
i
c
r
o
g
r
a
m
s

p
e
r

l
i
t
e
r
)

CPF087D
0
20
40
60
80
100
120
140
160
Jan-90
Jan-91
Jan-92
Jan-93
Jan-94
Jan-95
Jan-96
Jan-97
Jan-98
Jan-99
Jan-00
Jan-01
Jan-02
Jan-03
ch
l

a

(
m
i
c
r
o
g
r
a
m
s

p
e
r

l
i
t
e
r
)

CPF08801A
0
20
40
60
80
100
120
140
160
Jan-90
Jan-91
Jan-92
Jan-93
Jan-94
Jan-95
Jan-96
Jan-97
Jan-98
Jan-99
Jan-00
Jan-01
Jan-02
Jan-03
ch
l

a

(
m
i
c
r
o
g
r
a
m
s

p
e
r

l
i
t
e
r
)

Figure 6: Chlorophyll a concentrations collected by DWQ for 1990 - 2003 at three stations,
CPF087B3, CPF087D, and CPF08801A, in the Lower New Hope Arm of Jordan Reservoir. Data
from 9/96 - 1/01 are uncorrected concentrations.
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 15

CPF055C
0
20
40
60
80
100
120
140
160
Jan-90
Jan-91
Jan-92
Jan-93
Jan-94
Jan-95
Jan-96
Jan-97
Jan-98
Jan-99
Jan-00
Jan-01
Jan-02
Jan-03
ch
l

a

(
m
i
c
r
o
g
r
a
m
s

p
e
r

l
i
t
e
r
)

CPF055E
0
20
40
60
80
100
120
140
160
Jan-90
Jan-91
Jan-92
Jan-93
Jan-94
Jan-95
Jan-96
Jan-97
Jan-98
Jan-99
Jan-00
Jan-01
Jan-02
Jan-03
ch
l

a

(
m
i
c
r
o
g
r
a
m
s

p
e
r

l
i
t
e
r
)

Figure 7: Chlorophyll a concentrations collected by DWQ for 1990 - 2003 at two stations,
CPF055C and CPF055E, in the Haw River Arm of Jordan Reservoir. Data from 9/96 - 1/01 are
uncorrected concentrations.
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 16
Table 2. Summary statistics for nutrients (mg/l) and chlorophyll a (µg/l) collected by DWQ at
selected stations in the Jordan Reservoir (1990-2003). Data for Lower Hope Arm Stations
CPF087D and CPF08801A are not shown because those stations were not monitored continuously
during these time periods. Chlorophyll a data from 9/96 – 1/01 are uncorrected for phaeophytin
concentrations.

TP TN chl a TP TN chl a
CPF081A1C
Mean 0.11 0.66 48.3 0.09 0.77 48.3
Median 0.11 0.64 55.0 0.10 0.71 42.5
N 16 16 15 40 40 36
Std. Dev. 0.04 0.16 32.4 0.03 0.37 24.4
CPF086C
Mean 0.10 0.65 44.9 0.08 0.72 45.4
Median 0.10 0.65 44.0 0.08 0.65 37.0
N 16 16 15 40 40 38
Std. Dev. 0.03 0.12 26.8 0.02 0.35 23.3
CPF086F
Mean 0.08 0.64 37.7 0.07 0.69 40.4
Median 0.08 0.70 41.0 0.07 0.61 34.5
N 16 16 15 39 39 38
Std. Dev. 0.03 0.15 20.1 0.02 0.27 23.2
CPF087B3
Mean 0.04 0.55 20.33 0.04 0.55 26.49
Median 0.04 0.51 18.00 0.04 0.59 22.00
N 16 16 15 40 40 38
Std. Dev. 0.02 0.10 10.10 0.02 0.20 17.23
CPF055C
Mean 0.09 0.78 31.13 0.11 0.87 38.27
Median 0.08 0.75 26.00 0.08 0.85 32.00
N 16 16 15 39 39 37
Std. Dev. 0.04 0.17 20.35 0.14 0.33 33.66
CPF055E
Mean 0.06 0.66 23.87 0.06 0.67 30.00
Median 0.05 0.61 22.00 0.05 0.71 24.00
N 16 16 15 40 40 38
Std. Dev. 0.03 0.18 11.27 0.02 0.23 16.39
Ha
w

R
i
v
e
r

A
r
m
Lo
w
e
r

N
e
w

Ho
p
e

A
r
m
1990-1996 1997-2003
Up
p
e
r

N
e
w

H
o
p
e

A
r
m
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 17
4 Source Assessment

Elevated nutrient concentrations in Jordan Reservoir result from a combination of point and
nonpoint source loads. The point source loads include three major wastewater treatment plants at
the headwaters of the New Hope arm and seven major wastewater treatment plants upstream on the
Haw River. There are also several smaller dischargers. Nonpoint loading includes runoff from
urban areas in Durham, Chapel Hill, Cary, Burlington, Greensboro, and several other small
municipalities, as well as a variety of rural sources.

4.1 Point Source Assessment

All wastewater discharges to surface water in the State of North Carolina must receive a permit to
control water pollution. The Clean Water Act of 1972 initiated strict control of wastewater
discharges with responsibility of enforcement given to the Environmental Protection Agency
(EPA). The EPA then created the National Pollutant Discharge Elimination System (NPDES) to
track and control point sources of pollution. The primary method of control is by issuing permits to
discharge with limitations on wastewater flow and constituents. The EPA delegated permitting
authority to the State of North Carolina in 1975. Table 3 presents large and small dischargers in
the Upper New Hope Arm watershed, and Table 4 presents those for the Haw River Arm
watershed. Locations of dischargers in the Jordan Reservoir are shown in Figure 8.

NPDES wastewater permits are distinguished between individual and general. General permits are
issued for a given statewide activity such as the discharge of wastewaters associated with sand
dredging or non-contact cooling. Individual permits are permits developed and issued on a case-
by-case basis for activities not covered by general permits. These permits can be readily identified
by their prefix. Individual NPDES permits have the prefix NC while general NPDES permits have
the prefix NCG. General wastewater permits currently exist for the following activities: Non-
contact cooling water discharges; Petroleum-based groundwater remediation; Sand dredging;
Seafood packaging; and Domestic discharges from single family residences. Tables 3 and 4 list the
continuous wastewater discharges into the Upper New Hope and Haw River Arms of Jordan
Reservoir. There is one permitted discharger in the Lower New Hope Management Area.
Fearrington Utilities, Inc., Fearrington Utilities WWTP (NC0043559) has a permitted flow of 0.5
MGD with an average annual TN load of 8138 lb/yr and an average annual TP load of 566 lb/yr.

Table 3. Continuous point source dischargers in the Upper New Hope Watershed of Jordan
Reservoir.

Permit

Owner

Type
Average Annual
Flow (MGD)
(1997-2001)
Average Annual
TN Load (lbs)
(1997-2001)
Average
Annual TP
Load (lbs)
(1997-2001)
NC0047597 City of Durham/ South Durham
WRF
Municipal ,
Large
10.23 199,126 13,977
NC0025241 Orange Water & Sewer
Authority/ Mason Farm WWTP
Municipal ,
Large
8.13 313,155 10,395
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 18

Permit

Owner

Type
Average Annual
Flow (MGD)
(1997-2001)
Average Annual
TN Load (lbs)
(1997-2001)
Average
Annual TP
Load (lbs)
(1997-2001)
NC0026051 Durham County/ Triangle
WWTP
Municipal ,
Large
3.86 170,021 9,391
NC0056413 Whippoorwill LLC/ Carolina
Meadows WWTP
100% Domestic
< 1MGD
0.114 5,284 540
NC0051314 North Chatham Water & Sewer
Company, LLC/ Cole Park
Plaza
100% Domestic
< 1MGD
0.013 700 55
NC0043257 Nature Trails Association,
CLP/ Nature Trails Mobile
Home Park WWTP
100% Domestic
< 1MGD
0.032 2,795 525
NC0042803 Birchwood Mobile Home Park/
Birchwood Mobile Home Park
100% Domestic
< 1MGD
0.011 831 225
NC0074446 Hilltop Mobile Home Park/
Hilltop Mobile Home Park
100% Domestic
< 1MGD
0.003 414 49
NC0048429 Cedar Village Apartments/
Cedar Village Apartments
100% Domestic
< 1MGD
0.002 161 33
NC0025305 UNC Chapel Hill/ UNC
Cogeneration Facility
Industrial
Process &
Commercial
--- --- ---
NC0081591 Town of Cary/ Cary & Apex
WTP
Water Plants and
Water
Conditioning
--- --- ---
NC0082210 Orange Water & Sewer
Authority/ Jones Ferry Road
WTP
Water Plants and
Water
Conditioning
--- --- ---
NC0084093 County of Chatham/ Jordan
Lake WTP
Water Plants and
Water
Conditioning
--- --- ---
NC0086827 Brenntag/ Brenntag Southeast,
Inc.
Groundwater
Remediation
--- --- ---
Totals 22.40 692,488 35,210

Table 4. Continuous point source dischargers in the Haw River Arm watershed of Jordan
Reservoir.

Permit

Owner

Type
Average Annual
Flow (MGD)
(1997-2001)
Average Annual
TN Load (lbs)
(1997-2001)
Average
Annual TP
Load (lbs)
(1997-2001)
NC0047384 City of Greensboro/ T.Z.
Osborne WWTP
Municipal, Large 18.606 552,397 75,871
NC0024325 City of Greensboro/ North
Buffalo WWTP
Municipal, Large 13.058 510,119 63,382
NC0023868 City of Burlington/ Eastside
WWTP
Municipal, Large 6.65 311,609 27,217
NC0023876 City of Burlington/ Southside
WWTP
Municipal, Large 7.762 184,015 21,571
NC0024881 City of Reidsville/ Reidsville
WWTP
Municipal, Large 3.14 56,151 8,113
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 19

Permit

Owner

Type
Average Annual
Flow (MGD)
(1997-2001)
Average Annual
TN Load (lbs)
(1997-2001)
Average
Annual TP
Load (lbs)
(1997-2001)
NC0021211 City of Graham/ Graham
WWTP
Municipal, Large 1.826 51,328 10,294
NC0021474 City of Mebane/ Mebane
WWTP
Municipal, Large 0.984 25,509 3,928
NC0020354 Town of Pittsboro/ Pittsboro
WWTP
Municipal, <
1MGD
0.314 15,613 1,759
NC0066966 Quarterstone Farm
Homeowners Association/
Quarterstone Farm WWTP
100% Domestic
< 1MGD
0.054 3,250 341
NC0022691 Chateau Communities, Inc./
Autumn Forest Mfr. Home
100% Domestic
< 1MGD
0.061 3,427 329
NC0022675 Country Club Communities
LLC/ Birmingham Place
100% Domestic
< 1MGD
0.033 1,237 136
NC0042285 Trails Property Owners Assoc./
Trails WWTP
100% Domestic
< 1MGD
0.011 488 193
NC0046043 Oak Ridge Military Academy/
Oak Ridge Military Academy
100% Domestic
< 1MGD
0.011 838 209
NC0077968 Horners Mobile Home Park/
Horners Mobile Home Park
100% Domestic
< 1MGD
0.008 358 30
NC0042528 B Everett Jordan & Son – 1927
LLC
100% Domestic
< 1MGD
0.002 184 26
NC0038156 Guilford County Schools/
Northeast Middle & Senior
High WWTP
100% Domestic
< 1MGD
0.009 1,565 156
NC0073571 Mervyn R. King/ Countryside
Manor WWTP
100% Domestic
< 1MGD
0.006 228 39
NC0035866 County of Chatham/ Bynum
WWTP
Municipal, <
1MGD
0.012 1,025 146
NC0029726 NC Department of Correction/
Guilford Correctional Center
100% Domestic
< 1MGD
0.016 772 57
NC0065412 REA Enterprises, LLC/
Pleasant Ridge WWTP
100% Domestic
< 1MGD
0.014 417 44
NC0046809 Pentecostal Holiness Church/
Pentecostal Holiness Church
100% Domestic
< 1MGD
0.001 51 5
NC0060259 Willow Oak Mobile Home
Park/ Willow Oak Mobile
Home Park
100% Domestic
< 1MGD
0.009 894 122
NC0031607 Alamance-Burlington School
System/ Western Alamance
Middle School
100% Domestic
< 1MGD
0.005 681 61
NC0046019 Episcopal Diocese of North
Carolina/ The Summit WWTP
100% Domestic
< 1MGD
0.002 44 5
NC0045161 Alamance-Burlington School
System/ Altamahaw/ Ossipee
Elementary
100% Domestic
< 1MGD
0.003 383 39
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 20

Permit

Owner

Type
Average Annual
Flow (MGD)
(1997-2001)
Average Annual
TN Load (lbs)
(1997-2001)
Average
Annual TP
Load (lbs)
(1997-2001)
NC0045144 Alamance-Burlington School
System/ Western Alamance
High School
100% Domestic
< 1MGD
0.005 743 77
NC0038172 Guilford County Schools/
McLeansville Middle School
100% Domestic
< 1MGD
0.001 2,044 123
NC0022098 Cedar Valley Communities
LLC/ Cedar Valley WWTP
100% Domestic
< 1MGD
0.007 367 88
NC0045152 Alamance-Burlington School
System/ Jordan Elementary
100% Domestic
< 1MGD
0.002 232 37
NC0055271 Shields Mobile Home Park/
Shields Mobile Home Park
100% Domestic
< 1MGD
0.002 150 17
NC0038164 Guilford County Schools/
Nathanael Greene Elementary
100% Domestic
< 1MGD
0.003 469 40
NC0036994 Rockingham County Board of
Education/ Monroeton
Elementary School
100% Domestic
< 1MGD
0.002 71 61
NC0066010 Rockingham County Board of
Education/ Williamsburg
Elementary School
100% Domestic
< 1MGD
0.002 51 65
NC0045128 Alamance-Burlington School
System/ Sylvan Elementary
School
100% Domestic
< 1MGD
0.002 232 32
NC0003671 Amoco Oil Company/ Amoco
Greensboro Terminal
Industrial
Process &
Commercial
--- --- ---
NC0071463 Apex Oil Company/ Apex Oil
Company
Industrial
Process &
Commercial
--- --- ---
NC0003913 Glen Raven Inc/ Altamahaw
Division plant
Industrial
Process &
Commercial
0.021 251 48
NC0001210 Monarch Hosiery Mills Inc./
Monarch Hosiery Mills, Inc.
Industrial
Process &
Commercial
0.024 2,609 124
NC0001384 Burlington Industries, Inc./
Williamsburg plant
Industrial
Process &
Commercial
0.007 943 88
NC0048241 Staley Hosiery Mills/ Staley
Hosiery Mills
Industrial
Process &
Commercial
0.005 21 324
Totals 52.68 1,730,765 215,195

Certain types of stormwater runoff are covered under the NPDES permit program (Figures 8 and
9). Regulated discharges are those associated with large and small municipalities with municipal
separate storm sewer systems (MS4s). Phase I of this permitting program, established in 1990,
includes large municipalities serving populations greater than 100,000. In North Carolina, there are
six permitted local governments that have municipal separate storm sewer systems (MS4s) serving
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 21
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Greensboro
Durham
Burlington
Chapel Hill
Graham
Reidsville
Mebane
Cary
Pittsboro Apex
Morrisville
Jordan streams 2a.shp
Jordan mb.shp
Cb100.shp
Jordan watershed.shp
Jordan lake.shp
#Jordan anops.shp
#Jordan sw permits.shp
#Jordan gen ww permits.shp
#Jordan npdes ww permits.shp
0 20 Miles
N
EW
S
NPDES permits
General permits
Stormwater permits
Animal operations
Lake
Watershed boundary
County boundaries

Streams
populations of 100,000 or more (Raleigh, Durham, Fayetteville and Cumberland County, Charlotte,
Winston-Salem, Greensboro). Durham (NCS000249) and Greensboro (NCS000248) are the Phase
I municipalities draining to Jordan Reservoir. Stormwater from Durham discharges to the Upper
New Hope Arm of the reservoir, while stormwater from Greensboro discharges to the Haw River
Arm of the reservoir.

Industrial facilities that fall into one of the subject ten categories are required obtain permit
coverage under a general permit or an individual permit for stormwater.

Figure 8. Locations of NPDES wastewater permits, NPDES stormwater permits, and certified
confined animal operations in the Jordan Reservoir watershed.

Phase II of the NPDES Stormwater program was signed into law in December 1999. Regulated
small MS4s were required to apply for permit coverage by March 2003. Additional activities or
jurisdictions may be designated for coverage under the program based upon the potential for
significant water quality impacts. Phase I and II MS4 permits are listed in Table 5. EPA requires
that loads allocated to NPDES permitted stormwater be placed in the wasteload allocation (WLA),
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 22
which had previously been reserved for continuous point source loads (Wayland, 2002). The NC
Department of Transportation also has a NPDES stormwater permit in this watershed (statewide).

Table 5. Stormwater MS4 permits in the watershed of Jordan Reservoir.
Permit number Entity Reservoir management area
NCS000248 City of Greensboro Haw River Arm
NCS000401 (a) Guilford County Haw River Arm
NCS000402 City of Mebane Haw River Arm
NCS000403 Town of Elon Haw River Arm
NCS000404 Town of Haw River Haw River Arm
NCS000405 Town of Gibsonville Haw River Arm
NCS000408 City of Graham Haw River Arm
NCS000428 City of Burlington Haw River Arm
NCS000463 Town of Green Level Haw River Arm
NCS000477 Town of Swepsonville Haw River Arm
NCS000483 Town of Kernersville Haw River Arm
NCS000508 Piedmont Triad Airport Authority Haw River Arm
NCS000446 Town of Apex Lower New Hope Arm
NCS000250 NC Department of Transportation Statewide
NCS000427 City of Cary Upper and Lower New Hope Arm
NCS000433 (a) Wake County Upper and Lower New Hope Arm
NCS000249 City of Durham Upper New Hope Arm
NCS000414 City of Chapel Hill Upper New Hope Arm
NCS000450 City of Carrboro Upper New Hope Arm
NCS000465 Town of Morrisville Upper New Hope Arm
(a) Application in process

Land application systems for animal waste contribute nutrients to the hydrologic system. Animal
operations that are designed for, and actually serve, greater than or equal to the following number
of animals must be have a certified animal waste management plan under 15A NCAC 02H .0201:
100 head of cattle, 75 horses, 250 swine, 1,000 sheep, 30,000 birds with a liquid waste system.
There are 38 such facilities in the Jordan Reservoir watershed (31 dairy; 7 swine; Figure 7). Any
farm that has animal numbers meeting the federal threshold numbers or any farm that has had a
recent discharge violation must obtain a federal NPDES Permit. Federal Threshold Numbers are:
2500 Swine greater than 55 pounds in weight, 700 Mature Dairy Cattle, 1,000 Beef Cattle in
confinement, and 30,000 Poultry with liquid waste management system. General permits for
animal operations have been approved for swine, poultry, and cattle.

4.2 Non-Point Source Assessment

Non-point sources are diffuse sources that typically cannot be identified as entering a water body at
a single location. These sources of nutrients are typically runoff constituents from surfaces during
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 23
storm events. However, some sources may allow nutrients to be leached to shallow groundwater
and subsequently transported to surface waters.

Agricultural and urban land uses can contribute considerable amounts of nutrients due to fertilizer
use. In the Upper New Hope Management Area, agriculture makes up only approximately 4% of
land use (Figure 3). The Upper New Hope Arm is developed more intensely than the Haw River
Arm, which has 24% agriculture land use. Impervious surfaces associated with developed areas
increase the quantity and velocity of runoff and associated contaminants.

Septic systems are a potential source of nutrients to water bodies. Septic systems are designed to
pre-treat the sewage before it is applied to the soil via a drain field. The soil matrix provides
biological, chemical, and physical treatment for nutrients. However, the extent of treatment
depends on factors such as soil type, hydrology, and weather conditions of the site.

Lack of maintenance and improper use can cause septic systems to fail, creating the potential for
increased transport of nutrients to water bodies. A study by the NC Office of Budget and
Management suggested that 11% of systems surveyed had malfunctions or failures (NC DEH,
2000). Based on the CDM (1989) study for Little River Reservoir and Lake Michie subwatersheds,
a 10-15 percent steady-state rate of septic system failure was assumed, 20 percent of which is
sufficiently close to waterbodies to cause direct loading of nutrients. These septic failures are illicit
discharges and there are programs in place to detect and deter illicit discharges.

No comprehensive, up-to-date coverage of sewer service areas is available for the entire watershed.
Data from the 1990 census indicate the following sewer usage proportions (NC DEH, 1999). :
• Alamance County, 62% of population,
• Chatham County, 33% of population,
• Durham County, 91% of population, and
• Orange County, 68% of population.
The reporting conditions for Guilford County are incorrect and not presented in this document.
The 2000 census did not collect information on sewage and septic. Sanitary sewer overflows
(SSO) and sewer pipe leaks may also contribute to nutrient loading of Jordan Reservoir.

According to the NC Division of Forest Resources, managed forest activity (cut and reforestation)
totaled approximately 15,423 acres in Chatham, Durham, Alamance, Orange and Guilford Counties
between 1997 and 2001 (Raval, 2004). Assuming all of the activity occurred within the Jordan
Reservoir watershed (activities are not tracked by watershed), it would represent approximately 1%
of the total area and 3% of the total forested land use. In addition, managed forest in the Jordan
Reservoir watershed generally does not receive fertilization (Raval, 2004).

B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 24
5 Modeling Approach

The existing data memorandum (Tetra Tech 2001) documents the application of a scoping-level,
steady-state model of average annual lake response. This model does an adequate job of explaining
the spatial gradients in average chlorophyll a concentrations in the lake in a given year. A single
set of model parameters did not appear to fully capture the year-to-year variability in lake response.
This likely reflects: (1) variability in nutrient loss to sedimentation associated with differing
hydraulic patterns, (2) the complex, time-dependent interaction between the New Hope and Haw
River management areas, and (3) the inability of the model to fully distinguish between algal
responses in the short residence time Haw River arm versus the longer residence time New Hope
arm.

Accordingly, it appeared that a more sophisticated modeling approach would be required to meet
the needs for a calibrated nutrient response model. Specifically, an appropriate deterministic
modeling tool should be able to: address dynamic changes in response on an intra-seasonal scale;
represent the actual pattern of mixing between lake management areas; and include a representation
of nutrient cycling that can represent nutrient-algal and water column-sediment interactions at a
more sophisticated, process-based level.

In April 1999, the EMC approved a joint proposal from seven local governments to develop the
Jordan Reservoir Nutrient Response Model. The original "Project Partners" included Burlington,
Graham, Greensboro, Mebane, Orange Water and Sewer Authority, Pittsboro, and Reidsville.
Subsequently, the cities of Apex and Cary joined as Project Partners.

In July 2002, the Jordan Reservoir Nutrient Response Model, developed for the Jordan Reservoir
Project Partners by Tetra Tech, Inc., was delivered to the NC Environmental Management
Commission. The model was developed under a requirement of the NC Clean Water
Responsibility Act (HB 515). The model is a linked system that relies on Environmental Fluid
Dynamics Code (EFDC) and Water Analysis Simulation Program (WASP) model simulations.

Later in 2002, DWQ placed the upper New Hope Arm of Jordan Reservoir on the 303(d) list of
impaired waters requiring estimation of a Total Maximum Daily Load (TMDL) to meet the water
quality criterion for chlorophyll a. DWQ selected the Jordan Reservoir Nutrient Response Model
as a tool to develop the nutrient TMDL required by EPA.

Tetra Tech assisted DWQ in enhancing the Jordan Reservoir model for use in TMDL development
and lake management, and developing additional watershed nutrient loading analysis tools.
Additional data from an extensive monitoring study conducted by DWQ from late 2000 through
2001 was used for additional validation testing and calibration of the Jordan Reservoir Nutrient
Response Model. Also, a spreadsheet-based model was developed that combines Generalized
Watershed Loading Function (GWLF) model simulation of seasonal nutrient loads coupled with a
stream transport and delivery model that can estimate both the point and nonpoint source
component nutrient delivery to the lake.

B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 25
5.1 Jordan Reservoir Response Model Enhancement - Summary

What follows is a summary of the lake nutrient response modeling. Detailed documentation is
contained within two volumes: Tetra Tech (2002) and Tetra Tech (2003a).

The model is a linked system: hydrodynamic output and temperature simulation generated by
EFDC (Hamrick, 1996) are input to the WASP water quality model (Ambrose et al., 1993) to
account for the dynamic processes of lake mixing, seasonal changes, and nutrient cycling. A model
representation of the lake and associated segmentation is shown in Figure 9. The EFDC and
WASP input files require extensive amounts of data to predict nutrient cycling in Jordan Reservoir.
Meteorology, hydrology, and nutrient loading must be considered simultaneously to predict
impacts on the algal community. FLUX (Walker, 1987) is used to integrate observed concentration
data and continuous flow series to create time series of loads, which are used to establish the
tributary boundary loads for the Jordan Reservoir Nutrient Response Model.

The original nutrient response model was developed and calibrated based primarily on data
collected from 1997 to 2000 (Tetra Tech, 2002). The subsequent application of the lake response
model to 2001 was originally intended solely as a validation test of the previous calibration. The
initial 2001 validation, however, was only partially successful, necessitating a constrained
recalibration of the entire model.

Initial results for the recalibrated model showed that the simulation for 2001 did not meet the pre-
specified criteria for average absolute prediction error at all monitoring stations, and tended to
under-predict nutrient and algal concentrations during portions of the year. Changes in analytical
laboratories and procedures as well as changes for in-lake and tributary monitoring for 2001 are
some suspected sources of uncertainty. A final recalibration was undertaken with the intention of
obtaining the best fit to both the 1997-1999 and 2001 results. Despite some inaccuracies in the
simulation, the recalibrated model continues to provide a good representation of nutrient response
in Jordan Reservoir.
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 26

Figure 9. WASP model surface segments for Jordan Reservoir (outline at flood pool elevation).
Major discharges and withdrawals are identified.

Highlights of the recalibrated model and validation:

• During the final recalibration, a compromise was made between fit for the 1997-1999 and
2001 periods. This results in a small degradation in the quality of fit. The resulting average
absolute errors are often greater than the desired maxima of 0.25 for total nitrogen and
0.025 for total phosphorus. However, the errors for 1997-1999 and 2001 are generally of
opposite sign and compensating.
• The model provides a good representation of summer algal concentrations for 1997-2001,
represented as chlorophyll a, throughout the lake. The model, however, appears to under-
predict chlorophyll a concentrations reported by NC DWQ during the fall of 2000 and
2001. For 2000, the fall chlorophyll a data are uncorrected for pheophytin. These issues
were, however, resolved for the 2001 sampling. Thus, apparent under-estimation of
chlorophyll a in fall 2001 should be considered in model interpretation and application.
• The 2000 lake data were not used in the recalibration process, and are therefore available
for model validation. Unfortunately, only a limited amount of tributary data is available for
2000, so a relatively high degree of uncertainty in estimation of tributary loads is expected
for this year. This fit yields some noticeable improvements over the results for 2000
15 13
14
12 11
10
4
8
9
5
7
1
3 2
6Haw River
Greensboro
Burlington
Mebane
Reidsville
Graham
OWASA Durham
Durham Co.
Cary/Apex Withdrawal
Outflow
Pittsboro
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 27
presented for the previous model calibration (Tetra Tech, 2002). The only major
discrepancies in the 2000 results are for fall chlorophyll a concentrations.
• Figure 10 provides a color ramp of simulated chlorophyll a concentrations (average) and
frequency of concentrations greater than 40 µg/L for Jordan Reservoir, 1997-2001.

5.1.1 Special Issue: Carbon to Chlorophyll a Ratio

The water quality modeling tool is based on the EPA WASP5/EUTRO model. This model does
not simulate chlorophyll a directly. Rather, it simulates phytoplankton carbon and converts this
carbon concentration to a chlorophyll a concentration for reporting purposes based on a
carbon:chlorophyll ratio. In addition, the model simulates algae as a single group.

This formulation limits the ability of the model to represent the effects of seasonal changes in algal
species composition on chlorophyll a concentrations. Two major factors may influence the
apparent difference in chlorophyll response during the fall season: First, there is a shift in species
composition from summer dominance by cyanophytes to a mixed assemblage with a large
proportion of diatoms. Second, available light for photosynthesis declines during the fall, causing
algae to adjust their internal carbon:chlorophyll ratio.

The model is calibrated primarily to summer conditions, and thus reflects growth kinetic
coefficients and a carbon: chlorophyll ratio typical of cyanophyte dominance in high light
conditions (a ratio of 50 is used for calibration to observed chlorophyll a). Algae present in the fall
typically have a lower ratio under good light conditions (more chlorophyll a per unit of carbon),
and this ratio is likely to further decrease as available light declines.

The use of a theoretical calculation of carbon: chlorophyll ratios was explored for portions of the
year not dominated by cyanophytes to improve the apparent fit between model predictions and
observations. Note that interpretation with an alternate ratio does not affect the internal simulation,
which uses algal carbon as a state variable. That this approach is an appropriate one is suggested
by the fact that nutrient concentrations appear to fit reasonably well in the fall, suggesting that the
discrepancies in chlorophyll a do not represent an actual change in algal density and algal activity
that would alter the nutrient balance.

The results indicated that a fall chlorophyll a prediction calculated with the theoretical carbon:
chlorophyll ratio (varied by month according to environmental conditions) does tend to provide a
better fit to the observed fall values. It does not, however, provide a precise fit, and appears to
underestimate November observations in the lower portion of the reservoir. One possibility is that
some of the apparent deviation between model and observations in the fall could also be due to
different algal kinetic coefficients (e.g., growth rates, cell nutrient content, Michaelis-Menton
coefficients, etc.) for the algal assemblage present in the fall. Representation of different algal
groups is not readily feasible within the existing model. Therefore, no adjustment to the model was
made based on this analysis.
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 28

Figure 10. Simulated chlorophyll a concentrations (average) and frequency of concentrations
greater than 40 µg/L for Jordan Reservoir, 1997-2001. Graphs indicate normal pool overlaid on
flood elevation.

10 - 15
15 - 20
20 - 30
30 - 40
> 40
Chlorophyll a (µg/L)
US 64
SR 1008
Percent Days
> 40 µg/L
0% - 5%
5% - 10%
10% - 15%
15% - 20%
20% - 30%
30% - 40%
> 40%
US 64
SR 1008
10 - 15
15 - 20
20 - 30
30 - 40
> 40
Chlorophyll a (µg/L)
US 64
SR 1008
US 64
SR 1008
Percent Days
> 40 µg/L
0% - 5%
5% - 10%
10% - 15%
15% - 20%
20% - 30%
30% - 40%
> 40%
Full Year Results
May – September Results
10 - 15
15 - 20
20 - 30
30 - 40
> 40
Chlorophyll a (µg/L)
US 64
SR 1008
10 - 15
15 - 20
20 - 30
30 - 40
> 40
Chlorophyll a (µg/L)
US 64
SR 1008
US 64
SR 1008
Percent Days
> 40 µg/L
0% - 5%
5% - 10%
10% - 15%
15% - 20%
20% - 30%
30% - 40%
> 40%
US 64
SR 1008
Percent Days
> 40 µg/L
0% - 5%
5% - 10%
10% - 15%
15% - 20%
20% - 30%
30% - 40%
> 40%
US 64
SR 1008
US 64
SR 1008
10 - 15
15 - 20
20 - 30
30 - 40
> 40
Chlorophyll a (µg/L)
US 64
SR 1008
10 - 15
15 - 20
20 - 30
30 - 40
> 40
Chlorophyll a (µg/L)
US 64
SR 1008
US 64
SR 1008
US 64
SR 1008
Percent Days
> 40 µg/L
0% - 5%
5% - 10%
10% - 15%
15% - 20%
20% - 30%
30% - 40%
> 40%
US 64
SR 1008
US 64
SR 1008
Percent Days
> 40 µg/L
0% - 5%
5% - 10%
10% - 15%
15% - 20%
20% - 30%
30% - 40%
> 40%
Full Year Results
May – September Results
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 29
5.1.2 Nutrient Limitation

After recalibration, the conclusions regarding the important role of light limitation remain
unchanged, but some refinements of the conclusions regarding nutrient limitation are required.
Over the course of the simulation period, the most significant nutrient limitation alternates between
nitrogen and phosphorus, with neither nutrient exerting strong limitation during the cold season.
During the warm season (May-September) nitrogen is estimated to remain the most limiting
nutrient - although it was less limiting during 2001, when there were higher inorganic nitrogen
loads relative to phosphorus loads than in earlier years.

For the Upper New Hope Arm, nitrogen is the predominant limiting nutrient, because most of the
nitrogen is tied up in organic forms. Within the remainder of the lake, nutrient limitation alternates
between nitrogen and phosphorus, indicating an approximate balance between the available
inorganic fractions of nitrogen and phosphorus.

5.1.3 Existing Nutrient Loads to Jordan Reservoir

Nutrient loads to Jordan Reservoir were calculated based on the input loads to the nutrient response
model. Since these loads do not consider the source of the load, point or nonpoint, an additional
calculation was made to determine the potential point and nonpoint source contributions to the
loading at the lake. Two different methods of determining these contributions were utilized during
this project. The first method, described in this section, utilizes the end-of-pipe effluent data
reported on discharge monitoring reports (DMRs)and the effluent nutrient delivery model (RTI
2002a). The second method utilizes the watershed loading model described in Section 6.2.

These loads due to continuous point sources were calculated in two steps, as follows:
• First, the load generated at the effluent pipe was calculated. This generated load is also
referred to as the end-of-pipe load or simply the point source load. To correspond with the
nutrient response model, effluent loads were calculated for each year of the entire modeled
period, 1997-2001. An average annual load from those five years, as shown in Tables 6 and
7, was carried forward through the analysis
• Second, the generated load was mathematically transported down-river to Jordan Reservoir.
The load that is transported down-river is referred to as the delivered load. The delivered
load is calculated using the generated load and transport factors obtained from the RTI
Jordan Reservoir Nutrient Delivery Model. (RTI 2002a).
All loads are rounded to the nearest pound. The calculation of point source loads based on DMR
data is not without uncertainty. While flow is measured daily, TN and TP concentrations are
measured monthly or weekly depending upon the facility. The exception to this is OWASA, which
collects daily TP. A simple calculation of annual load based on monthly averages is usually
unreliable. Fill-in techniques must be used to generate daily time series that is then used to
calculate the annual load values. Annual loads were calculated using methods described in RTI
(2002a). Fill-in techniques allow a more reliable and less biased estimation of annual load.
In order to be consistent with lake hydrology, point source loads are summarized based on the area
of the lake that received the delivered load. There are three different areas considered for this
exercise based on the hydrology, subsequent nutrient response model segmentation (Figure 9), and
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 30
nutrient response model results (Figure 10). The three areas are the Upper New Hope Arm, which
corresponds to model segments 1 through 4 in Figure 8, the Lower New Hope Arm, which
corresponds to model segments 5 through 13, and the Haw River Arm, which corresponds to model
segments 14 and 15. Summaries of generated and delivered loads are presented in Tables 6 and 7
for the Upper New Hope and Haw River Arms of Jordan Reservoir, respectively. The Fearrington
Utilities, Inc., Fearrington Utilities WWTP (NC0043559) in the Lower New Hope Arm has an
average annual TN load of 8138 lb/yr and an average annual TP load of 566 lb/yr. Transport
factors of 84% and 88% for TN and TP, respectively, result in average annual delivered loads of
6836 lb/yr TN and 498 lb/yr TP for this facility.

Table 6. Nutrient Load Delivered to the Upper New Hope Arm of Jordan Reservoir by continuous
NPDES dischargers
Average Annual
Generated Load,
1997-2001 (lbs)
Transport
Factors (a)
Average Annual
Delivered Load,
1997-2001 (lbs)

Permit

Owner
TN TP TN TP TN TP
NC0047597 City of Durham/
South Durham WRF
199,126 13,977 75% 67% 149,345 9,378
NC0025241 Orange Water &
Sewer Authority/
Mason Farm WWTP
313,155 10,395 63% 47% 197,288 4,886
NC0026051 Durham County/
Triangle WWTP
170,021 9,391 96% 97% 163,220 9,110
NC0056413 Whippoorwill LLC/
Carolina Meadows
WWTP
5,284 540 63% 47% 3,329 254
NC0051314 North Chatham
Water & Sewer
Company, LLC/ Cole
Park Plaza
700 55 81% 84% 567 47
NC0043257 Nature Trails
Association, CLP/
Nature Trails Mobile
Home Park WWTP
2,795 525 81% 84% 2,264 441
NC0042803 Birchwood Mobile
Home Park/
Birchwood Mobile
Home Park
831 225 70% 64% 582 144
NC0074446 Hilltop Mobile Home
Park/ Hilltop Mobile
Home Park
414 49 70% 64% 290 31
NC0048429 Cedar Village
Apartments/ Cedar
Village Apartments
161 33 100% 100% 161 33
Totals 692,488 35,210 517,045 24,324
(a) Obtained from the Jordan Reservoir Nutrient Delivery Model (RTI 2002a).
(b) Calculated by multiplying the facility generated load by the facility transport factor.

B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 31
Table 7. Nutrient Load Delivered to the Haw River Arm of Jordan Reservoir by continuous
NPDES dischargers
Average Annual
Generated Load, 1997-
2001 (lbs)
Transport Factors
(a)
Average Annual
Delivered Load, 1997-
2001 (lbs)

Permit

Owner
TN TP TN TP TN TP
NC0047384 City of Greensboro/
T.Z. Osborne WWTP
552,397 75,871 45% 44% 248,579 33,383
NC0024325 City of Greensboro/
North Buffalo
WWTP
510,119 63,382 43% 42% 219,351 26,620
NC0023868 City of Burlington/
Eastside WWTP
311,609 27,217 77% 69% 239,939 18,779
NC0023876 City of Burlington/
Southside WWTP
184,015 21,571 80% 73% 147,212 15,747
NC0024881 City of Reidsville/
Reidsville WWTP
56,151 8,113 66% 56% 37,060 3,543
NC0021211 City of Graham/
Graham WWTP
51,328 10,294 81% 71% 41,576 7,309
NC0021474 City of Mebane/
Mebane WWTP
25,509 3,928 56% 55% 14,285 2,161
NC0020354 Town of Pittsboro/
Pittsboro WWTP
15,613 1,759 76% 82% 111,866 1,442
NC0066966 Quarterstone Farm
Homeowners
Association/
Quarterstone Farm
WWTP
3,520 341 50% 43% 1,625 147
NC0022691 Chateau
Communities, Inc./
Autumn Forest Mfr.
Home
3,427 329 52% 46% 1,782 151
NC0022675 Country Club
Communities LLC/
Birmingham Place
1,237 136 55% 52% 680 71
NC0042285 Trails Property
Owners Assoc./
Trails WWTP
488 193 84% 76% 410 147
NC0046043 Oak Ridge Military
Academy/ Oak Ridge
Military Academy
838 209 46% 41% 386 86
NC0077968 Horners Mobile
Home Park/ Horners
Mobile Home Park
358 30 58% 49% 208 15
NC0042528 B Everett Jordan &
Son – 1927 LLC
184 26 84% 76% 155 19
NC0038156 Guilford County
Schools/ Northeast
Middle & Senior
High WWTP
1,565 156 52% 46% 814 72
NC0073571 Mervyn R. King/
Countryside Manor
WWTP
228 39 42% 38% 96 15
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 32
Average Annual
Generated Load, 1997-
2001 (lbs)
Transport Factors
(a)
Average Annual
Delivered Load, 1997-
2001 (lbs)

Permit

Owner
TN TP TN TP TN TP
NC0035866 County of Chatham/
Bynum WWTP
1,025 146 84% 76% 861 111
NC0029726 NC Department of
Correction/ Guilford
Correctional Center
772 57 36% 34% 278 19
NC0065412 REA Enterprises,
LLC/ Pleasant Ridge
WWTP
417 44 51% 45% 213 20
NC0046809 Pentecostal Holiness
Church/ Pentecostal
Holiness Church
51 5 46% 41% 24 2
NC0060259 Willow Oak Mobile
Home Park/ Willow
Oak Mobile Home
Park
894 122 51% 45% 456 55
NC0031607 Alamance-Burlington
School System/
Western Alamance
Middle School
681 61 64% 58% 436 36
NC0046019 Episcopal Diocese of
North Carolina/ The
Summit WWTP
44 5 46% 41% 20 2
NC0045161 Alamance-Burlington
School System/
Altamahaw/ Ossipee
Elementary
383 39 58% 49% 222 19
NC0045144 Alamance-Burlington
School System/
Western Alamance
High School
743 77 64% 58% 476 45
NC0038172 Guilford County
Schools/
McLeansville Middle
School
2,044 123 36% 34% 736 42
NC0022098 Cedar Valley
Communities LLC/
Cedar Valley WWTP
367 88 55% 52% 202 46
NC0045152 Alamance-Burlington
School System/
Jordan Elementary
232 37 84% 76% 195 28
NC0055271 Shields Mobile Home
Park/ Shields Mobile
Home Park
150 17 64% 58% 96 10
NC0038164 Guilford County
Schools/ Nathanael
Greene Elementary
469 40 75% 66% 352 27
NC0036994 Rockingham County
Board of Education/
Monroeton
Elementary School
71 61 42% 38% 30 23
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 33
Average Annual
Generated Load, 1997-
2001 (lbs)
Transport Factors
(a)
Average Annual
Delivered Load, 1997-
2001 (lbs)

Permit

Owner
TN TP TN TP TN TP
NC0066010 Rockingham County
Board of Education/
Williamsburg
Elementary School
51 65 51% 45% 26 29
NC0045128 Alamance-Burlington
School System/
Sylvan Elementary
School
232 32 84% 76% 195 24
NC0003671 Amoco Oil
Company/ Amoco
Greensboro Terminal
--- --- --- --- --- ---
NC0071463 Apex Oil Company/
Apex Oil Company
--- --- --- --- --- ---
NC0003913 Glen Raven Inc/
Altamahaw Division
plant
251 48 58% 49% 146 23
NC0001210 Monarch Hosiery
Mills Inc./ Monarch
Hosiery Mills, Inc.
2,609 124 58% 49% 2,513 61
NC0001384 Burlington Industries,
Inc./ Williamsburg
plant
943 88 48% 47% 453 41
NC0048241 Staley Hosiery Mills/
Staley Hosiery Mills
21 324 74% 65% 16 211
Totals 1,730,765 215,195 972,964 111,580
(a) Obtained from the Jordan Reservoir Nutrient Delivery Model (RTI 2002a).
(b) Calculated by multiplying the facility generated load by the facility transport factor.

Using the above delivered loading for point sources and the loading utilized for the calibrated
reservoir model, the total nutrient loading for the baseline period (1997 through 2001) is presented
in Table 8. Nonpoint source loads for each management area of the reservoir were calculated by
difference.

Table 8. Existing nutrient loads to Jordan Reservoir (1997-2001 average in lb/yr).
Total Load Point
Sources
% Point
Sources
Nonpoint
Sources
% Nonpoint
Sources
Total Nitrogen
Haw 2,790,217 972,964 35% 1,817,253 65%
Upper New Hope 986,186 517,045 52% 469,141 48%
Lower New Hope 221,929 6,836 3% 215,093 97%
Total Phosphorus
Haw 378,569 111,580 29% 266,989 71%
Upper New Hope 87,245 24,324 28% 62,921 72%
Lower New Hope 26,574 498 2% 26,076 98%
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DWQ Modeling & TMDL Unit 34
The nonpoint source loads shown in Table 8 include those from traditional nonpoint sources as
well as loads from stormwater.
5.2 Watershed Model Development - Summary

The lake model is driven by observations of flow and nutrient loads in tributaries to the lake,
calculated using the FLUX model. This reliance on observations meant that it was not necessary to
develop a full watershed model to implement the lake model. However, as part of the analyses
performed for that work, RTI developed a point source nutrient delivery tool to estimate the
fractions of discharged point source nutrient loads that are delivered to the lake. This work was
based on national parameters for an instream loss model, and not calibrated to site-specific
observations. In addition, the existing suite of tools did not explicitly represent the sources of
nonpoint nutrient loads within the Jordan Reservoir watershed. The Jordan Reservoir nutrient
response model provides an ideal platform with which to evaluate the impacts of a range of nutrient
reduction scenarios. However, additional watershed nutrient loading analysis tools were desired to
provide a foundation for attributing and evaluating nutrient load sources, delivery, and management
opportunities within the watershed. A summary of the watershed modeling for Jordan Reservoir is
provided below. Detailed documentation is provided in Tetra Tech (2003b).

Nonpoint loading of water and nutrients is simulated in the Jordan Reservoir watershed using the
Generalized Watershed Loading Function (GWLF) model (Haith et al., 1992). The complexity of
this loading function model falls between that of detailed simulation models and simple export
coefficient models. GWLF provides a mechanistic, simplified simulation of precipitation-driven
runoff and sediment delivery. Solids load, runoff, and groundwater seepage can then be used to
estimate particulate and dissolved-phase nutrient delivery to a stream, based on concentrations in
soil, runoff, and groundwater.

The GWLF model provides a well-accepted tool for generating seasonal loads at the small
watershed scale. However, GWLF is limited in its ability to simulate large watersheds (such as the
Haw River drainage) as it does not explicitly represent nutrient transformations and losses during
transport through the stream network and upstream impoundments. Therefore, a spreadsheet-based
model was developed that combines GWLF simulation of seasonal loads at the 14-digit HUC scale
coupled with a stream transport/delivery model that can estimate both the point and nonpoint
source component nutrient delivery to the lake. Such a tool provides a basis to estimate nutrient
load allocations by addressing over-land runoff, septic system input, groundwater discharge into
streams, and nutrient delivery to Jordan Reservoir.

The spreadsheet model incorporates a nonpoint loading series that ties nutrient load generation to
land use and meteorology. The loading series are developed for the major land use, geology and
soil areas in the watershed, drawing to a large extent upon existing GWLF calibrations local to the
area, including the Cane Creek Reservoir watershed and the Falls Lake watershed. Quarterly and
annual loads are generated based on variations in hydrology using the example GWLF models to
calibrate the loading factors for the entire watershed. Point source loads are input to the
spreadsheet according to outfall location in the stream network. The stream network and delivery
component of the spreadsheet are based on an enhanced and refined version of the RTI Jordan
Reservoir Nutrient Delivery Model (JLNDM).
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 35

5.2.1 Land Use

An improved land use database was created consisting of the 1992 National Land Cover Database
(NLCD) from the Multi-Resolution Land Characterization (MRLC) Consortium, updated in
Orange, Durham, Chatham, and Wake counties using current tax parcel information, and updated
in all other areas for residential density using the 2000 Census. This yields a near-current estimate
of land use in the basin, with the primary exception that commercial/industrial development in the
Haw River basin that occurred after the date of the NLCD.

5.2.2 Hydrologic Response Units

The U.S Department of Agriculture - Natural Resources Conservation Service (USDA-NRCS)
delineated the Jordan Reservoir watershed into 58 hydrologic units (HUCs), averaging 29 square
miles. For analytical and planning purposes, these units were categorized into one of 14 nutrient
response zones based on soil erodibility, geographic region, and rainfall-runoff response.

For model development, unit (per-acre) watershed loads are combined with estimates of delivery to
the lake. Different unit loads are appropriate for different areas of the watershed, due to differences
in precipitation patterns and soil characteristics. Those areas with similar characteristics can be
combined for the analysis of unit loads. Such areas of similar characteristics are termed hydrologic
response units or HRUs.

5.2.3 GWLF Development

The GWLF application requires information on land use distribution, meteorology, and parameters
that govern runoff, erosion, and nutrient load generation. In addition to the land use database, four
primary data input classes are used to develop the model parameters for the watershed simulations:
1) soil and hydrologic properties, 2) nutrient concentration, buildup, and runoff assumptions, 3)
onsite wastewater disposal information, and 4) meteorological data. The land use, watershed
delineations, population, septic numbers, and meteorology data were collected and processed to
generate a multi-year time series (April 1991 - March 2000 meteorology), which was used to derive
seasonal and annual loading rates by land use type for each model HRU.

Nutrient loading from different land uses is based on the volume of flow and its pathways
(overland or seepage), the amount of soil eroded, and coefficients that express the amount of
nutrient load per unit volume of flow or erosion from a given land use.

GWLF is used to generate unit-loading rates for Jordan Reservoir watershed land uses within 14
nutrient response zones that encompass each of the 58 hydrologic units within the basin. Average
loading rates by land use are summarized in Table 9.

B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 36
5.2.4 Stream Delivery Model

The stream network delivery model relates the field scale loading estimates by land use and
measured point source loads to the delivered or exerted load at Jordan Reservoir. Three types of
factors are assessed: major stream delivery rates, representing the fraction delivered from point
source discharges or the pour points of 14-digit HUCs during stream/river transport, trapping
within impoundments, and local-scale trapping within 14-digit HUCs. All three factors serve to
reduce the delivered nutrient load.

Table 9. Summary of Average Annual Field-Scale Loading Rates by Land Use Across all HRUs
(lb/ac/yr).
Code Land use description TN TP
BAR Barren 45.96 29.92
CIT Commercial/Heavy Industrial 24.05 3.70
FOR Forest 1.59 0.33
OFF Office/Light Industrial 16.47 2.63
PAS Pasture 5.69 1.08
RVH Residential <0.25 ac per du (sewered) 15.03 2.47
RHH Residential – 0.25-0.5 ac per du (sewered) 11.86 2.00
RMH Residential – 0.5-1.0 ac per du (sewered) 11.72 1.94
S-RMH Residential – 0.5-1.0 ac per du (unsewered) 41.42 2.03
RML Residential – 1.0-1.5 ac per du (sewered) 10.89 1.81
S-RML Residential – 1.0-1.5 ac per du (unsewered) 28.71 1.86
RLL Residential – 1.5-2.0 ac per du (sewered) 9.37 1.71
S-RLL Residential – 1.5-2.0 ac per du (unsewered) 22.09 1.74
RVL Residential – 2.0+ ac per du (sewered) 2.49 0.60
S-RVL Residential – 2.0+ ac per du (unsewered) 11.40 0.63
ROW Row Crop 13.37 5.32
UGR Urban Green Space 3.57 0.61
WAT Water 0.00 0.00
WET Wetland 2.20 0.40

Delivery through the major stream network is represented using a methodology similar to the
transport component of the USGS SPARROW approach (Smith et al., 1997). SPARROW refers to
spatially referenced regressions of contaminant transport on watershed attributes, and was
developed based on nationwide USGS NASQAN monitoring of 414 stations. The model
empirically estimates the origin and fate of contaminants in streams, and quantifies uncertainties in
these estimates based on model coefficient error and unexplained variability in the observed data.

The SPARROW tool actually contains two portions, one to generate loads and one to account for
mass transport through stream reaches. The approach used for the Jordan Reservoir watershed is to
use GWLF to generate the loads at the 14-digit HUC scale and then apply the portion of
SPARROW that estimates instream transport losses.

B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 37
Initial estimates of rates of nutrient transmission within the stream network were developed by
RTI. The major stream delivery rates in the spreadsheet model were initially adjusted and then
modified during calibration to achieve qualitative agreement with loads calculated by FLUX.
Nutrient removal in these lakes was approximated using the same second order sedimentation rate
equations employed in the BATHTUB model (Walker, 1987).

The nonpoint load is subject to three types of removal: retention in the local HUC, removal by
lakes, and removal during instream transport. In contrast, the point source loads are subject only to
removal during instream transport (none of the point sources are upstream of major
impoundments). As a result, the delivered fraction for point sources is on average much higher
than the delivered fraction for nonpoint sources, even though point and nonpoint sources are
subject to the same instream removal processes.

5.2.5 Watershed Model Results

Sources of the nonpoint nitrogen and phosphorus load in the Upper New Hope Management Area
are summarized in Figure 11. The Jordan Reservoir watershed contains a complex overlay of
municipal and county jurisdictions with responsibility for the management of point and nonpoint
sources. These jurisdictional boundaries typically do not correspond with subwatershed
boundaries, which complicates any analysis of loads from individual jurisdictions to specific
management areas of the lake. A useful summary is provided by analyzing exerted loads (loads
delivered to the lake) by county. This is obtained by overlaying county and HUC boundaries, and
weighting the exerted load from each HUC by area in a given county. Results are shown in Table
10.

Figure 11. Sources of nitrogen (left panel) and phosphorus (right panel) nonpoint source loading to
Jordan Reservoir in the Upper New Hope Arm.

Table 11 shows the percentage breakdown between point and nonpoint load sources delivered to
Jordan Reservoir on a long term average basis. During the baseline period for the TMDL, the
Residential
39%
Comm/Indus
21%
Agriculture
10%
Forest
19%
Other
11%Residential
29%
Comm/Indus
18%Agriculture
17%
Forest
19%
Other
17%
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 38
proportions will be different due to a drier hydrological condition. The nonpoint loads represent
the long-term average derived from a 9-year simulation with the watershed model, while the point
source loads represent the average delivered load for 1996-1998, the period for which RTI
conducted a detailed analysis. The percentage contribution of point sources to nitrogen loads is
similar to previous estimates (e.g., Tetra Tech, 2002) made without a calibrated watershed model.
However, the point source contribution of phosphorus is less than was previously estimated, due to
changes in the rates of instream trapping made during calibration of the delivery model.

Table 10. Distribution of Point and Nonpoint Source Nutrient Load Delivered to Jordan Reservoir
by County.
County Nonpoint load Point source load Total delivered Percent of total
Total nitrogen
Alamance 1,057,181 551,935 1,609,117 32.1%
Caswell 39,540 0 39,540 0.8%
Chatham 648,685 13,902 662,586 13.2%
Durham 251,321 298,027 549,348 11.0%
Forsyth 3,089 0 3,089 0.1%
Guilford 698,739 556,505 1,255,244 25.0%
Orange 395,160 156,728 551,888 11.0%
Randolph 8,686 0 8,686 0.2%
Rockingham 140,240 41,799 182,039 3.6%
Wake 151,527 0 151,527 3.0%
Total 3,394,168 1,618,896 5,013,064
Total phosphorus
Alamance 244,814 45,679 290,493 34.1%
Caswell 5,505 0 5,505 0.6%
Chatham 160,706 2,383 163,089 19.2%
Durham 42,691 15,445 58,136 6.8%
Forsyth 566 0 566 0.1%
Guilford 132,043 60,986 193,029 22.7%
Orange 72,930 4,702 77,631 9.1%
Randolph 2,062 0 2,062 0.2%
Rockingham 32,384 3,987 36,371 4.3%
Wake 24,520 0 24,520 2.9%
Total 718,221 133,182 851,403

B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 39
Table 11. Long-term average proportions of point and nonpoint source loads in the Jordan
Reservoir watershed.
Watershed area Point sources Nonpoint sources
Total nitrogen
Haw River Arm 32% 68%
Upper New Hope Arm 45% 55%
Lower New Hope Arm 4% 96%
Total phosphorus
Haw River Arm 18% 82%
Upper New Hope Arm 17% 83%
Lower New Hope Arm 2% 98%

B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

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6 Reduction Targets

Reductions targets were evaluated for each area of the reservoir, as presented in Section 5. Thus,
three different sets of reduction targets were calculated for Jordan Reservoir. All targets were
derived consistent with methodology for TMDLs, regardless of current listing status. This was
performed in order to avoid inconsistencies that could occur as a result of overlapping state
programs for nutrient sensitive waters and federal programs for impaired waters.

6.1 Total Maximum Daily Load (TMDL)

A Total Maximum Daily Load is the maximum amount of a pollutant that a water body can receive
and still meet water quality standards, partitioned among point and nonpoint sources. 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), expressed by the equation:

TMDL = Σ WLA + Σ LA + MOS

The objectives of the TMDL are to estimate allowable pollutant loads, and to allocate them among
the general pollutant sources in the watershed. 40 CFR §130.2 (i) states that TMDLs can be
expressed in terms of mass per time (e.g. pounds per day), toxicity, or other appropriate measures.
This TMDL will be expressed in terms of percent load reduction and allowable load of TN and TP.
Further analysis was required to determine the breakdown between point source (WLA) and
nonpoint source (LA) loadings that meet the TMDL objectives.

6.2 Model Scenarios

A 10 percent or less frequency of predicted (daily average) chlorophyll a concentrations greater
than 40 µg/L is taken as the frequency target for management. The use of a 10 percent frequency
as a target for completion of a chlorophyll a TMDL in North Carolina is supported by EPA. This
TMDL is expected to reduce the nutrient inputs to Jordan Reservoir that contribute to algal blooms
as indicated by chlorophyll a excursions. Nutrient load reductions developed using the water
quality model must insure that the state chlorophyll a standard of 40 µg/L or less will be met 90
percent of the time during critical conditions (i.e. summer months).

For spatial applicability, results could be analyzed for individual model segments, or as an
aggregate frequency across some or all of the model segments. Temporal applicability is also
subject to interpretation. Four potential options were evaluated for the each area of Jordan
Reservoir:

1. Long-term (five-year) frequency of excursions over all seasons,
2. Long-term (five-year) frequency of excursions for summer season (May-September) only,
3. Worst-case (individual 12-month window) annual frequency of excursions, and
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 41
4. Worst-case (individual year) frequency of excursions for summer season only.

Options 3 and 4 (the worst-case analyses) were subsequently dropped as overly restrictive and
unreliable. A finding of non-compliance from the model using a worst-case approach runs a
distinct risk of being caused by anomalies in the model forcing data, such as anomalies in the
estimates of tributary load, rather than reflecting actual conditions.

The two long-term analyses (options 1 and 2) were both carried forward for further analyses.
Option 1 (frequency over the entire simulation period) is consistent with the approach taken in the
Neuse Estuary TMDL, and is likely to be less restrictive than requiring a 10 percent or less
frequency during the summer season (because lower algal concentrations are expected in winter
and early spring). However, this option has a drawback in that the model appears to underestimate
chlorophyll a concentrations during the fall. Application of the 10 percent frequency target to a
summer season (Option 2) is consistent with the TMDLs for the Roberson Creek Cove of Jordan
Reservoir and Lake Wylie. Use of this option has the advantage of focusing on the period for
which the model performs best, while avoiding the fall period in which the model may under-
predict chlorophyll a concentrations.

The general strategy for scenarios was to run the calibrated water quality model for the full
simulation period (1997-2001) with modifications to external loading and analyze the resulting
predictions of chlorophyll a concentration in relation to magnitude and frequency targets. This
procedure yields an estimate of total loading reductions necessary to meet the target. At this stage,
the analysis does not distinguish between point and nonpoint loading components.

While algal growth in the Upper New Hope Arm of Jordan Reservoir is most strongly limited by
inorganic nitrogen, algae can be expected to respond to loads of both nitrogen and phosphorus.
This means that a loading target is potentially bivariate, consisting of a paired target loading rate
for both nitrogen and phosphorus.

The recalibrated model was used to evaluate load reduction scenarios for the lake. These scenarios
address the question, "What degree of reduction in existing nutrient loads, from all sources, would
be required to achieve water quality standards in the listed portions of the reservoir?" Results of
these scenarios were used to help formulate nutrient loading targets for all parts of the reservoir,
including the 303(d) listed portion. Figure 12 presents the final scenario recommended for target
setting representing summer season chlorophyll a response to changes in nutrient load to the Upper
New Hope. Results are based on aggregated model segments, weighted by segment volume,
considering summer seasons from 1997 – 2001 collectively.

Using the 8% exceedance line to incorporate an explicit margin of safety, a 35% reduction in
existing TN loading will be needed for the Upper New Hope Arm. A large fraction of TP load
would have to be reduced to discern an effect on chlorophyll a concentrations if less TN reduction
were sought. Since P is limiting for certain algal groups and during certain times of the year, a
small reduction will be sought (5%) along with the TN reductions in this nutrient-rich system. In
addition, model analysis indicates that changes in loads from the Haw River Arm have little effect
on conditions in the Upper Hew Hope Arm (Tetra Tech 2003). Since the Upper New Hope Arm
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 42
of the reservoir is currently on the state 303(d) list of impaired waters, this target is also equal to
the TMDL for the Upper New Hope Arm of Jordan Reservoir.

Figure 12. Volume-weighted aggregate responses to Jordan Reservoir load reductions in the Upper
New Hope Arm

The nutrient response model output was also reviewed to determine the TMDL for the Haw River
Arm of the reservoir. A bivariate plot of potential reductions in TP and TN was generated for the
Haw River Arm, using model segments 14 and 15, to evaluate appropriate actions. Results are
based on aggregated model segments, weighted by segment volume, considering summer seasons
from 1997 – 2001 collectively. Unlike the Upper New Hope Arm, chlorophyll a in the Haw River
Arm is predicted to react to smaller reductions in both nitrogen and phosphorus. As seen in Figure
13, a diagonal response line is associated with chlorophyll a standard compliance. Using the 8%
exceedance line to incorporate an explicit margin of safety, an 8% reduction in existing TN loading
and a 5% reduction in existing TP loading is needed for the Haw River Arm. Since the Haw River
Arm of the reservoir is currently on the state 303(d) list of impaired waters, this target is also equal
to the TMDL for the Haw River Arm of Jordan Reservoir.

Fraction of Existing Total N Load
Fr
a
c
t
i
o
n

o
f

E
x
i
s
t
i
n
g

T
o
t
a
l

P

L
o
a
d
0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
40.0
30.0
25.0
20.0
15.0
12.0
10.0
8.0
6.0
Percent of Chlorophyll
Excursions
(Observations > 40 µg/l)
Lumped Segments 1-4 Response to New Hope,
Northeast, and Morgan Creek Load Reductions
(volume-weighted average growing season frequency of excursions)
a
10%
35% TN
5% TP
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 43

Figure 13. Volume-weighted aggregate responses to Jordan Reservoir load reductions in the Haw
River Arm

The model predicted a very low frequency of standard violations in the Lower New Hope Arm.
Thus, a chart similar to those presented above in Figures 12 and 13 was not produced. Since the
model provides no basis for loading reductions in this portion of the lake, a cap on nutrient loading
is proposed for the watershed draining to this section of the reservoir. DWQ believes the
derivation of this cap is consistent with existing TMDL guidance. Since the Lower New Hope
Arm of the reservoir is currently on the state 303(d) list of impaired waters, this cap is also equal to
the TMDL for the Lower New Hope Arm of Jordan Reservoir. It should be noted that nutrient
reductions in the Upper New Hope and Haw River watershed areas are likely to have an impact on
the Lower New Hope Arm of the reservoir, resulting in less available nutrients for algal uptake.

A summary of loading targets for the management areas of Jordan Reservoir is shown in Table 12.

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Proportion of Existing Total N Load
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Proportion of Existing Total P Load
-1.0
6.0
8.0
10.0
12.0
15.0
20.0
25.0
30.0
40.0
Lumped Segments 14 & 15 Response
Percent of Chlorophyll a
Excursions
(Observations > 40 ug/l)
(volume-weighted average growing season frequency of excursions)
to Haw River Load Changes
10%
8% TN
5% TP
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 44
Table 12. Loading targets for the Jordan Reservoir management areas
Existing Load (lbs/yr) TMDL Reduction TMDL
Upper New Hope Arm
Total nitrogen 986,186 35% 641,021
Total phosphorus 87,245 5% 82,883
Lower New Hope Arm
Total nitrogen 221,929 N/A (a) 221,929
Total phosphorus 26,574 N/A (a) 26,574
Haw River Arm
Total nitrogen 2,790,217 8% 2,567,000
Total phosphorus 378,569 5% 359,641
(a) Loading capped at level equal to 1997-2001 baseline delivered loads.
6.3 Critical Conditions

Critical conditions can be considered a subset of seasonality: the most stringent of the seasons.
The years on which the model is developed are somewhat biased toward drier conditions, which
tend to promote algal growth by increasing residence time. The model simulation period contains a
wet year (1998) a normal year (1997) and three years that were drier than normal, although each
with different characteristics (1999-2001). However, the seasonal analysis shows that inflows and
precipitation were not extraordinarily low, except for local precipitation during the summer of
1999. The drought, in terms of water supply availability, was the cumulative effect of several years
of below normal precipitation and flow, and conditions, when examined on a seasonal basis, was
generally not so extraordinarily rare as to be unrepresentative of the expected range of lake
response. In addition, the TMDL is based on an annual load allocation necessary to achieve the
chlorophyll a target during the critical conditions (May through September).

6.4 Seasonal Variation

Seasonal variation is considered in the development of the TMDL. The allocation applies to all
seasons. Seasonal variation in hydrology, climatic conditions, and watershed activities are
represented through the use of a continuous flow gage and the use of all readily available water
quality data collected in the watershed. A wide range of flow conditions is modeled for this
TMDL, demonstrated by the inter-annual variation in hydrology.
6.5 Attainment of other Water Quality Standards
Allocations for nutrients in the Jordan Reservoir TMDL cannot result in violations of other water
quality standards (CWA § 303(d)(1)(C)), such as low dissolved oxygen or elevated pH. The North
Carolina fresh water standard for pH in Class C waters (T15A: 02B.0211) states that pH shall be
normal for the waters in the area, which generally shall range between 6.0 and 9.0 except that
swamp waters may have a pH as low as 4.3 if it is the result of natural conditions. Use support
assessment in the Haw Arm of Jordan Reservoir has revealed elevated pH with respect to the
standard in greater than 10 percent of samples since the time the lake was listed for chlorophyll a.
The Haw Arm was subsequently placed on the 2006 303(d) list for pH impairment. Algal blooms
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 45
can affect pH of fresh waters through the consumption of CO2 in photosynthesis during the day
(which effectively raises pH), and the release of CO2 in respiration during the night (which
effectively lowers pH). Attainment of the chlorophyll a standard as a result of this TMDL should
reduce the frequency of pH standard excursions. However, it is not known whether the number of
excursions will be reduced sufficiently to delist the reservoir for pH impairment. Further study will
be necessary to confirm or refute this possibility.

6.6 Model Uncertainty and Margin of Safety

There is uncertainty (in data, modeling tools, and scientific understanding) in the analysis
connecting specific levels of nutrient loads to predicted frequency of chlorophyll a concentrations
greater than 40 µg/L. The inability to accurately predict specific observed concentrations of
nutrients and chlorophyll a can be attributed to many sources: model error, lack of sufficient
information in source assessment, gaps in our scientific knowledge, natural variability, field and
laboratory measurement error, and lack of current site specific model input parameters and land use
information. Because of certain lack of site-specific information, professional judgment and
literature values were sometimes used. In sum, the model results should be interpreted in light of
the model limitations and prediction uncertainty.

The margin of safety is an additional factor of the TMDL that accounts for some of the uncertainty
in the relationship between pollutant loads and receiving water quality. This margin of safety can
be provided implicitly through conservative analytical assumptions and/or explicitly by reserving a
portion of the load capacity.

This TMDL utilizes an explicit margin of safety (MOS) applied to the water quality criterion. The
frequency of exceeding the criterion (40µg/L) has been reduced from 10% to 8%. In addition, 4 of
5 years (1997-2000) of chlorophyll a data used for model calibration represent uncorrected
chlorophyll a, which is a conservation estimate of corrected chlorophyll a.

6.6.1 Data Uncertainty

Uncorrected chlorophyll a data were used for model calibration during years 1997 through 2000.
In 2001, corrected chlorophyll a data are available, and were analyzed using the fluorometric
nonacidified method, which reduces pigment interference and does not actually require a
"correction" step. The correction is for pheophytin pigment, which is a degradation product that
can interfere with the chlorophyll a measurement. DWQ used the acidification method from 1981
to January 2001.

As discussed in Tetra Tech (2003), there is a high correlation between corrected and uncorrected
chlorophyll a. The ratio of uncorrected to corrected chlorophyll a data was close to one during
July- September, increasing during other seasons. Since the nutrient reduction targets are based on
model predictions in the summer season, overestimation of algal biomass due to use of uncorrected
chlorophyll a data is minimized. Other issues contributing to uncertainty regarding chlorophyll a
and nutrient data are discussed in Tetra Tech (2003).
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DWQ Modeling & TMDL Unit 46

6.6.2 Lake Model Uncertainty

The lake model is best judged on its ability to replicate longer-term spatial and temporal trends and
the frequency distribution of chlorophyll a concentrations greater than the criterion, rather than
focusing exclusively on uncertainty in model predictions of point-in-time/point-in-space
observations.

Model output should be viewed as a range of potential values based on their probability density
functions rather than as a precise single output number. The model provides a reasonable
representation of the expected distribution of concentrations (Tetra Tech, 2004). Error statistics do
indicate some deviations between observations and predictions for individual point-in-time/point-
in-space values (Tetra Tech, 2003a). Statistics for the volume-weighted aggregate segment
responses of the Jordan Reservoir model are presented in Appendix III.

In general, the calibration strategy for the model was to capture broad spatial trends and fit multiple
parameters simultaneously. The relationships between concentrations of multiple parameters at
multiple stations are more significant than the fit to individual points at individual stations. The
model fit is aimed at reproducing the central tendency of trends in time and the approximate
frequency distribution, rather than replicating individual observations of chlorophyll a. For these
purposes the model performs reasonably well.

Despite that model prediction of lake response is an inexact science, water quality models are
essential to management, providing quantitative guidance for decision-making. As with all
modeling projects, there is uncertainty in the data and the models used for Jordan Reservoir.
However, even the most well studied, data-rich systems will not allow for certainty in model
prediction (e.g., Neuse Estuary). Uncertainty does not preclude a decision to pursue a reasonable
management strategy. Post-implementation monitoring of the nutrient management strategy will
provide feedback for appropriate adaptive management.

6.6.3 Watershed Model Uncertainty

The combined load generation and delivery models provide a comprehensive analysis of nutrient
load delivery to Jordan Reservoir on a seasonal basis. Performance of the model was calibrated
against detailed information on point source discharges and FLUX analyses of delivered loads for
1996-1998, using hydrology derived from the Cape Fear Hydrologic Model (DHI and Moffett and
Nichols, 2000). All modeling components have been incorporated into a deliverable spreadsheet,
which can be readily modified to evaluate impacts of land use changes, alteration of unit loading
rate by Best Management Practices (BMPs), or changes in point source wasteload allocations.

Model calibration was performed for the 1996-1998 time period, which corresponded to the
availability of the detailed time series of point source reduction ratios calculated by RTI using the
CFHM hydrology ratios. Model results were compared to FLUX analysis estimates of actual load
in each of the tributary arms (Haw River, Morgan Creek, New Hope Creek, and Northeast Creek).
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The FLUX analyses were performed previously for the Jordan Reservoir nutrient response model
(Tetra Tech, 2002). An additional FLUX analysis was performed at an intermediate location on the
Haw River mainstem using data from the DWQ monitoring station at Saxapahaw, NC (station
B2000000). Since FLUX estimates loads from actual monitoring data, both delivered point source
and nonpoint source loads were included in the calibration.

After the adjustments to instream loss rates, the model provides a good approximation of the FLUX
estimates of loads for the calibration period. Apparent percent differences between the model and
FLUX estimates are less than or equal to 10 percent, except for phosphorus in Northeast Creek.
The difference in phosphorus for Northeast Creek is primarily due to an over-estimation in 1998,
and could reflect an inaccurate estimate of the point source loading component, estimated at 43
percent of the total phosphorus load for 1998.

Watershed models of nutrient loading are inherently subject to high levels of variability, consisting
of both uncertainty and natural variability. The natural variability arises because of year-to-year
changes in meteorology, plant/growth cover, and land management. Uncertainty reflects the facts
that simulation models are, at best, an approximation of reality, and the parameters of simulation
models are not known with a high level of precision. Natural variability, or at least that part of it
due to meteorology, is best addressed by simulation over a number of years that provide a selection
of different weather patterns. This section focuses on the portion of variability that is due to
prediction uncertainty.

GWLF application for the majority of the Jordan watershed is not calibrated to site-specific
observations (although it uses calibrations from watersheds in the area), which will increase
uncertainty. It appears reasonable, based on the Cadmus (1995, 1996) studies, to assume that
uncertainty in the estimation of cumulative loads is on the order of 10 percent. The load generation
and transport uncertainties are multiplicative. If the transport uncertainty is taken as ± 5 percent,
this leads to a range from -14 to +16 percent about the central estimate.

Some further evidence on uncertainty is provided by the comparison of 1996-1998 total loads
(point and nonpoint) from the model and FLUX. Error relative to FLUX on annual loads appears
to be on the order of ± 10 percent. This results, however, from adjustment of loss rates to achieve a
better fit. Bringing together lines of evidence suggests that the total uncertainty on cumulative
nutrient loads is likely to be on the order of 20 percent.
6.7 Blue Green Algae

Blue-green algae frequently dominate the summer phytoplankton community in eutrophic lakes,
including management areas of North Carolina's Jordan Reservoir. Phytoplankton communities in
eutrophic waters may contain the particularly noxious genera of Anabaena, Aphanizomenon, and
Mycrocystis. However, these genera are not dominant in Jordan Reservoir at present. Will the
proposed nutrient management targets for the lake unintentionally promote a dominance of these
noxious genera? The following discussion illuminates the issue.

There are many potential physical, chemical, and biological factors that can lead to blue green
dominance of an algal assemblage. Hyenstrand et al. (1998) discusses nine factors: nutrient ratio
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competition, differential light requirements, carbon dioxide competition, buoyancy, high
temperature tolerance, herbivory avoidance, cellular nutrient storage, ammonium-nitrogen
exploitation, and trace element competition.

Heterocysts are found in certain filamentous blue-green algae (e.g., Anabaena, Aphanizomenon)
enabling fixation of dinitrogen from the atmosphere for growth. In Jordan Reservoir, the dominant
blue-green algae (Oscillatoria) during 2003, and indeed in most years, were algae that do not have
heterocysts and thus incapable of N fixation (Vander Borgh, 2003).

The ability to fix N has been thought to play a factor in enabling certain blue-green algae to out-
compete other species and form noxious blooms when N is in limited supply at low N:P ratios.
This hypothesis was initiated by Schindler (1977) and Smith (1983). Along these lines, Smith
(2001) cautions against implementing N reduction, alone, or reducing the N:P loading ratios to
levels that may promote blue-green algae. Note that in Jordan Reservoir reductions to both
nutrients have been proposed.

On average, algae require nutrients in N:P ratios of approximately 7 to 1 by weight, known as the
Redfield (1958) ratio (16:1 molar; 7.2:1 weight). Deviations from this ratio in ambient water
samples may indicate a potential nutrient limitation. Ratios less than 7:1 tend toward N limitation
and higher ratios tend toward P limitation. In systems with an abundance of both nutrients, algal
growth may be limited by other factors such as light availability. Due to variability in algal
stoichiometry, the ratio should not be considered as an absolute threshold. Accordingly, Thomann
and Mueller (1987) suggested that ratios greater than 20:1 likely reflect P limited systems while
ratios of 5:1 or less may reflect N limited systems.

In Jordan Reservoir, the currently proposed nutrient reductions will result in average TN:TP
watershed loading to the lake in ratios equal to 8:1 to the Upper New Hope Arm, representing a
slight decrease for the Upper New Hope Arm. The targets for Jordan Reservoir will result in point
source-loading ratio of 14:1 or greater in the Upper New Hope Arm. The proposed reductions
should not result in dramatic alterations of the N:P ratios and the target loading ratios exceed the
Redfield ratio.

New light has been shed on the prevailing suggestion that low N:P ratios lead to blue-green algal
dominance. Ferber et al. (2004) and Downing et al. (2001) cast considerable doubt on the use of
N:P ratios as sole predictors of blue-green algal dominance. A multitude of factors contribute to
dominance by blue-green algae. Therefore, while the issue may remain somewhat equivocal, the
most recent science does not support the use of this hypothesis as a reason not to pursue nutrient
reductions. Continued monitoring, including monitoring of the algal community composition, will
enable DWQ to evaluate future lake response to these management strategies, allowing for adaptive
management as conditions in the lake warrant.

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7 Allocations

Both point and nonpoint sources bear an equal burden for nutrient reductions. For example, point
and nonpoint sources in the Upper New Hope Arm of Jordan Reservoir must individually reduce
nitrogen loads by 35%. This type of reduction strategy is consistent with North Carolina General
Statute 143-215.8B(b)(1).

The total allowable nitrogen and phosphorus loads to the reservoir were derived using the modeling
tools described previously. In each subdrainage of the reservoir, these loads were divided into the
allowable point and nonpoint source loads, referred to as the wasteload and load allocations (i.e.,
WLA and LA). The allowable loads are divided in the same PS:NPS proportions as were estimated
for the baseline period. The WLA was then divided among the existing NPDES dischargers as
described below.

The modeling tools take into account that some portion of the nutrients from any given source is
lost in transport to the reservoir due to instream processes. The load reaching the reservoir from a
particular source is less than the load generated at that source, and the percent loss depends on the
source's location in the drainage. As a result of these losses, allowable mass loadings for point
sources must be expressed in two different but equivalent forms: the load as it leaves the effluent
pipe (i.e., the generated load) and the load as it reaches the reservoir (i.e., the delivered load). The
wasteload allocation and the allocations for individual NPDES facilities are expressed as delivered
loads. However, permit limits are measured at the point of discharge, so nutrient limits are given in
terms of generated loads.

The allowable point and nonpoint source loads, referred to as the wasteload and load allocations,
were calculated using information from the modeling tools. Allowable mass loading for point
sources is calculated in two forms, the load as it reaches the reservoir (i.e., the delivered load) and
the load as it leaves the effluent pipe (i.e., the generated load). These are two different loading
rates and, due to instream losses, the load reaching the reservoir is always less than the load leaving
the effluent pipe or discharged from an upstream watershed. Thus, the wasteload allocation can be
expressed in terms of both the generated and the delivered loads. Wasteload and load allocations
presented below are in terms of the load delivered to the reservoir.

No attempt was made to separate permitted (WLA-SW) and nonpermitted (LA) loading associated
with nonpoint sources. EPA requires that loads allocated to NPDES permitted stormwater be
placed in the wasteload allocation, which had previously been reserved for continuous point source
loads (EPA 2002). Since the WLA allocation associated with NPDES permitted stormwater was
not separated in a formal manner, the percent reduction associated with the management area (i.e.
Upper New Hope Arm, Lower New Hope Arm, and Haw River Arm) will apply. According to the
Phase II rules, MS4 permittees are responsible for reducing the loads associated with stormwater
outfalls for which it owns or otherwise has responsible control.

The loading allocation for the Upper New Hope Arm of Jordan Reservoir is shown below in Table
13. This table presents the existing nutrient load at the lake, the fraction of that load from point
sources, the TMDL loads and the allocations between continuous discharging facilities
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DWQ Modeling & TMDL Unit 50
(wastewater) and permitted and non-permitted stormwater. The wasteload allocation for
wastewater was calculated by multiplying the TMDL by the fraction of the baseline load due to
point sources.

Table 13. Wasteload and load allocations for the three management areas of Jordan Reservoir (a)

(a) Wasteload and load allocations presented as delivered loads.
(b) Loading capped at level equal to 1997-2001 baseline nutrient loads.
(c) WLA-wastewater data for Lower New Hope Arm was inadvertently input as end-of-pipe load
instead of delivered load in the Public Review Draft TMDL. Data presented here reflect
delivered loads. LA plus WLA-stormwater load was also revised to reflect the change in
WLA.

The following sections describe the point and nonpoint source strategies developed as part of the
nutrient management strategy. Each portion of this strategy was developed over a 1½ year period
in a series of open meetings with extensive participation and input of the affected stakeholders.
7.1 Wasteload Allocations

The wasteload allocation (WLA) presented in Table 13 provides the total poundage of nitrogen and
phosphorus that continuous point sources may contribute. This loading is the load delivered to the
lake, versus the load generated at the wastewater treatment facility. As previously stated, the load
generated at the wastewater treatment facility naturally attenuates and a reduced load is delivered to
Jordan Lake. However, wastewater treatment NPDES permits are provided in terms of the load
generated at the facility, thus the allocation needs to reflect these loads. Non-nutrient bearing
loads, such as those from water treatment plants and cooling water, are not included in the
allocations.

There are numerous factors considered in the point source allocation strategy. These include the
distance from the reservoir and the amount and type of waste discharged. Weighting of the amount
of wasteload allocations for each facility was evaluated using the actual annual average flow during
the 1997-2001 period, the permitted flow during the 1997-2001 period, and the permitted flow in
2004. Although all three of these scenarios were considered, the final allocations are based on the
permitted flow in 2004.

Existing
Load
(lbs/yr)
% Point
Source
Load
TMDL
Reduction TMDL WLA-
wastewater
LA plus WLA
stormwater
Upper New Hope Arm
Total nitrogen 986,186 52% 35% 641,021 336,079 304,942
Total phosphorus 87,245 28% 5% 82,883 23,106 59,777
Lower New Hope Arm (c)
Total nitrogen 221,929 3% N/A (b) 221,929 6,836 215,093
Total phosphorus 26,574 2% N/A (b) 26,574 498 26,076
Haw River Arm
Total nitrogen 2,790,217 35% 8% 2,567,000 895,127 1,671,873
Total phosphorus 378,569 29% 5% 359,641 106,001 253,640
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The equivalent treatment concentration method was used to determine allocations. This method
satisfies NC General Statute 143-215.8B(b)(1) which requires equitable allocations. Thus, all
wastewater treatment plants received allocations based on equitable levels of technology.
Allocated annual generated loads were calculated by multiplying the maximum permitted flow by
the equivalent treatment concentration and a conversion factor (3,044). These loads will be used in
NPDES permits as annual loading targets. Compliance will be judged using the annual loads, not
the equivalent treatment concentration. Allocated annual delivered loads calculated by multiplying
allocated generated loads by the appropriate transport factor in Table 6. The sum of the allocated
annual delivered loads must equal the WLA in Table 13. Summaries of the wasteload allocation
analyses for the Upper New Hope Arm and Haw River Arm are listed below.

Upper New Hope Arm. All of the available loading was allocated to the existing facilities.
Therefore, there will be no new nitrogen or phosphorus bearing loads permitted in this watershed.
There are four facilities discharging greater than 100,000 gallons per day in the watershed of the
Upper New Hope Arm: The City of Durham- South Durham WRF, the Orange Water & Sewer
Authority- Mason Farm WWTP, the Durham County- Triangle WWTP, and the Whippoorwill
LLC- Carolina Meadows WWTP. These facilities account for 99.7% of the total permitted flow
from point sources. The discharge allocations for these four facilities provide equivalent
concentrations for each facility. For nitrogen, this equivalent concentration is 3.04 mg/L, and for
phosphorus this equivalent is 0.23 mg/L. The remaining facilities in the Upper New Hope
watershed were allocated at equivalent concentrations of 12.0 mg/L and 2.0 mg/L for nitrogen and
phosphorus, respectively.

Haw River Arm. All of the available loading was allocated to the existing facilities. Therefore,
there will be no new nitrogen or phosphorus bearing loads permitted in this watershed. There are
ten facilities discharging greater than 100,000 gallons per day in watershed of the Haw River Arm:
The City of Greensboro- T.Z. Osborne WWTP, the City of Greensboro- North Buffalo Creek
WWTP, the City of Burlington- Eastside WWTP, the City of Burlington- Southside WWTP, the
City of Reidsville- Reidsville WWTP, the City of Graham- Graham WWTP, the City of Mebane-
Mebane WWTP, the Town of Pittsboro- Pittsboro WWTP, the Quarterstone Farm Homeowners
Association- Quarterstone Farm WWTP, and the Glen Raven Inc- Altamahaw Division plant.
These facilities account for 99.3% of the total permitted flow from point sources. The discharge
allocations for these ten facilities provide equivalent treatment levels for each facility. For
nitrogen, this equivalent treatment level is 5.3 mg/L, and for phosphorus this equivalent is 0.67
mg/L. The remaining facilities in the Upper New Hope watershed were allocated at equivalent
concentrations of 12.0 mg/L and 2.0 mg/L for nitrogen and phosphorus, respectively.
7.1.1 Permitting Options

The strategy for point sources (i.e., wastewater dischargers) calls for all affected dischargers to
implement appropriate nutrient controls. Each facility will receive annual mass discharge limits for
total nitrogen and for total phosphorus in its NPDES permit. Limits will be expressed as end-of-
pipe limits, that is, limits that will apply at the point of discharge. In order to meet the new limits,
it will be necessary for most dischargers to upgrade their facilities to effectively remove nutrients.
The strategy also calls for all dischargers to optimize nutrient removal in their existing facilities
while modifications are designed and built.
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The compliance schedule for meeting the nutrient management strategy is outlined in NCGS §143-
215.1B(b)(iv). This section describes the following timeline for compliance: "a maximum of three
years to plan, design, finance, and construct a facility that will comply with those maximum mass
loads and concentration limits. If the Commission finds that additional time is needed to complete
the construction of a facility, the Commission may further extend an extended compliance date by a
maximum of two additional years."

The strategy provides two permitting options to interested dischargers in order to allow some
flexibility with target compliance. One option is a "bubble" permit, which allows individual
permittees with multiple permitted facilities to pool its nutrient limits. The second option is a
"group compliance" option, which allows multiple dischargers to pool the nutrient limits for their
various facilities and work collectively to meet their combined limits. Each of these options is
discussed in more detail below.

7.1.1.1 Bubble Permits

A bubble permit option allows any permittee with more than one permitted facility to meet the
combined nutrient limits of its facilities, rather than the individual limits for each facility. This
option is only available to the municipalities of Burlington and Greensboro, which own and operate
two wastewater treatment plants each. The option is voluntary and, if pursued, will be implemented
through modification of the affected NPDES permits.

Conformance with this TMDL will be determined in terms of the nutrient loads delivered to the
reservoir. Generated, or end-of-pipe, load limits for different facilities cannot be combined directly
because each discharger's transport losses are different. Thus, nutrient limits under a bubble permit
must be expressed as total delivered loads for the affected facilities.

The following equations will be used to establish combined limits in any such bubble permits and
to measure compliance with the TMDL:

For total nitrogen loading:

(M 1,N * TF 1,N ) + (M 2,N * TF 2,N ) = DL M,N

where
M 1,N = End-of-pipe annual nitrogen loading from facility 1, lbs/yr
M 2,N = End-of-pipe annual nitrogen loading from facility 2, lbs/yr
TF 1,N = Nitrogen transport factor for facility 1,
TF 2,N = Nitrogen transport factor for facility 2,
DL M,N= Allowable delivered nitrogen load from the municipality, lbs/year.

For total phosphorus loading:

(M 1,P * TF 1,P ) + (M 2,P * TF 2,P ) = DL M,P
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where
M 1,P = End-of-pipe annual phosphorus loading from facility 1, lbs/yr
M 2,P = End-of-pipe annual phosphorus loading from facility 2, lbs/yr
TF 1,P = Phosphorus transport factor for facility 1,
TF 2,P = Phosphorus transport factor for facility 2,
DL M,P= Allowable delivered phosphorus load from the municipality, lbs/yr.
NPDES Compliance Group

Similar to the bubble permit option, the group compliance option allows one or more groups of
permittees in the same subdrainage to work collectively to meet the combined nutrient limits of its
member facilities, rather than each facility being subject to its individual limits. Thus, it provides
interested dischargers to pursue an alternative approach to meeting the nutrient reduction goals of
the TMDL and allows dischargers, as a group, the flexibility to develop their own strategy for
doing so. This option is voluntary and is open to any interested discharger.

Each group will be governed through a group NPDES permit. The group permit will contain limits
for nitrogen and phosphorus only and will supplement the individual NPDES permits of the
member facilities. The individual permits will remain in full effect, including other effluent limits
and monitoring, reporting, and other requirements. The group permit will include a detailed list of
the co-permittee members, their individual and group nutrient allocations, reporting requirements
for the group, and procedures for modifying the permit to reflect changes in membership or
changes in individual or group allocations. The group permitting approach is expected to be similar
to that already employed in the Neuse River basin.

As with the bubble permit, the end-of-pipe limits for each facility under a compliance permit must
be converted and the new limits expressed in terms of delivered load. An association's nutrient
limits will be the sum of delivered nutrient allocations for its co-permittee members. Transfers of
mass loads would be allowed within management areas (i.e., Upper New Hope Arm watershed,
Haw River watershed), but not outside of the areas (i.e., load transfer from the Upper New Hope
Arm to the Haw River Arm watershed).

7.2 Load Allocations

The management of load allocations (i.e. nonpoint source loads) falls outside the requirements of
the TMDL, with the exception of developed lands that fall under the NPDES stormwater program.
The state is currently addressing NPDES stormwater statewide, including within the Jordan
watershed, as a separate effort. However, a conceptual nonpoint source management strategy was
developed as part of the Jordan stakeholder process. Using the stakeholders' recommendations, the
Division subsequently developed a proposed NPS management strategy. This strategy, rules, and
fiscal analysis can be found on the Environmental Management Commissions website at
http://h2o.enr.state.nc.us/admin/emc/2007/Mar08Agenda.htm under action item number three.

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Reasonable Assurance. EPA requires reasonable assurance that allocations will result in the water
body of concern meeting water quality standards. Reasonable assurance is a demonstration that
TMDLs will be implemented through regulatory or voluntary actions, including management
measures or other controls, by Federal, State or local governments, authorized Tribes, or
individuals. For nonpoint sources, storm water sources for which an NPDES permit is not
required, atmospheric deposition, ground water or background sources of a pollutant, the
demonstration of reasonable assurance must show that management measures or other control
actions to implement the load allocations contained in each TMDL meet the following four-part
test:
1. They specifically apply to the pollutant(s) and the waterbody for which the TMDL is being
established;
2. They will be implemented as expeditiously as practicable;
3. They will be accomplished through reliable and effective delivery mechanisms; and
4. They will be supported by adequate water quality funding.

Rules have been established for the Jordan Reservoir watershed that strive to reduce nitrogen and
phosphorus loading to the lake. These rules include provisions for nutrient management, runoff
from agricultural operations, stormwater controls for both existing and new development, and the
protection and maintenance of riparian buffers. These rules will be effective soon after they
become implemented.

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8 Future Efforts

This nutrient management strategy and TMDL represents an early phase of a long-term restoration
project to reduce nutrient loading in the Jordan Reservoir watershed. The implementation of these
reductions will take many years, particularly in the case of nonpoint sources of pollution. As such,
it may be many years before improvement in Jordan Reservoir is noted.

Using the results of the trend analysis of watershed loading and lake response, the NCDWQ will
determine if progress has been made towards meeting the water quality standards and loading
targets. If the trend analyses indicate that the reservoir is improving or that nutrient loads are
decreasing, NCDWQ will not reopen the TMDL to adjust target loading rates downward.

The Division currently considers equivalent concentrations of 3.0 mg/L TN and 0.18 mg/L TP as
the limits of wastewater treatment technology. While the equivalent concentrations for wastewater
dischargers in the Haw River Arm watershed of Jordan Reservoir are greater than the limits of
technology, the margin is significantly less for those in the Upper New Hope Arm watershed. This
will affect any potential expansion of major wastewater treatment facilities in Durham, Chapel Hill,
and Durham County. These large wastewater treatment facilities in the upper New Hope Arm
watershed of Jordan Reservoir are allocated at equivalent concentrations of 3.04 mg/L TN. These
facilities would, therefore, be subject to the limits of wastewater treatment technology for total
nitrogen. Future opportunities to increase wastewater treatment capacity without increasing
nitrogen loading will come from technological improvements in the industry or from effluent re-
use programs. Equivalent concentrations of total phosphorus are greater than the level considered
the limit of wastewater technology. Thus, opportunities to increase wastewater treatment capacity
without increasing phosphorus loading can be achieved by utilizing the best available technology.

The NCDWQ has an approved nutrient criteria development plan that includes a re-evaluation of
the existing chlorophyll a standard and a review of other potential indicators of nutrient
enrichment. Changes to the water quality standard will warrant a re-opening of the TMDL to
evaluate if the reduction targets continue to be appropriate.

Phase II of this TMDL addressing pH impairment of the Haw River arm of Jordan Reservoir has
been scheduled to begin in 2012. This effort will require additional field monitoring and modeling
to allocate nutrient loading among point and non-point sources in the watershed.
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Public Participation

Two stakeholder processes occurred during the development of this nutrient management strategy
and TMDL. The first process was through the efforts of the Project Partners. During the initial
development of the data review technical memorandum and the nutrient response model, the
Project Partners held regular meetings with DWQ staff. At major completion steps, the Project
Partners convened greater stakeholder meetings to share and discuss results of the data review and
the modeling.

DWQ staff, the Triangle J Council of Governments, and the Piedmont Triad Council of
Governments initialized a more formal stakeholder process to carry a greater group of stakeholders
forward through the development of management targets and the management strategy. A USEPA
grant, in the amount of $29,730, was used to support this stakeholder process. A total of 21
stakeholder meetings were held between May 2003 and December 2004 to discuss TMDL
development, modeling issues, target setting, and management strategy development. The councils
of governments prepared a stakeholder report that includes descriptions of the meetings,
stakeholder comments and concerns, and recommendations (TJCOG 2005). The Triangle J
Council of Governments also continues to maintain a project website, with links to presentations
and handouts posted regularly. Materials can be downloaded from this website at
http://www.tjcog.dst.nc.us/regplan/jorlknm.htm#.

The following excerpt was taken from the stakeholder report:

Source: TJCOG 2005
The stakeholders generated many recommendations for the Jordan Lake TMDL and nutrient management
strategy. These recommendations are condensed into the Results section and address the TMDL, nutrient
targets, nutrient allocations, nutrient management strategies and water quality monitoring for Jordan Lake and its
watershed. The recommendations and concerns are grouped by topic and represent a summary of the entire
series of stakeholder meetings.

All of the stakeholder recommendations are consistent with three overarching recommendations, and all
stakeholder concerns could be addressed within that framework. The three overarching stakeholder
recommendations are as follows:
1. All of the stakeholders supported an adaptive management approach for the TMDL, nutrient targets,
and nutrient management strategy.
2. All of the stakeholders supported a phased implementation of the nutrient management strategy.
Most of the stakeholders were interested in exploring the possibility of a nutrient trading program.

The three overarching recommendations could address the concerns about data quality, model uncertainty, and
model validity, as well as the concerns about the costs and feasibility of implementation, while at the same time
providing certainty that the water quality objective for Jordan Lake would be achieved. The adaptive
management approach with phased implementation supported by the stakeholders is more conservative than
typical adaptive management approaches to TMDLs, because an explicity margin of safety would be included in
the TMDL and nutrient target calculations from the beginning. The phased implementation approach for the
nutrient management strategy would apply to the point and nonpoint source nutrient management strategies.
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9 References

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Gilbert, R.O. 1987. Statistical Methods for Environmental Pollution Monitoring. Van Nostrand
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Haith, D.A., R. Mandel, and R.S. Wu. 1992. GWLF, Generalized Watershed Loading Functions,
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Hamrick, J.M. 1996. User's Manual for the Environmental Fluid Dynamics Computer Code.
Special Report No. 331 in Applied Marine Science and Ocean Engineering. Virginia Institute of
Marine Science, The College of William and Mary, Gloucester Point, VA.

B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 58
Hyenstrand, P., Blomqvist, P., and Petterson, A. 1998. Factors determining cyanobacterial success
in aquatic systems-a literature review. Arch. Hydrobiol. Spec. Issues Adv. Limnol. 15: 41-62.

North Carolina Department of Agriculture. 2001. Agricultural Statistics Division-County Statistics.
www.ncagr.com/stats/cntysumm/ and http://govinfo.library.orst.edu/cgi-
bin/agstate?North+Carolina.

North Carolina Division of Environmental Health (NCDEH). NCDENR. 1999. North Carolina On-
Site Wastewater Non-Point Source (NPS) Pollution Program.
www.deh.enr.state.nc.us/oww/nonpointsource/ NPS.htm June 24, 1999.

North Carolina Division of Environmental Health (NCDEH). NCDENR. 2000. Report on the
Proper Maintenance of Septic Tank Systems in Accordance with Section 13.5 of HB 1160 (Clean
Water Act of 1999). http://www.deh.enr.state.nc.us/oww/Maintenance.PDF. March 15, 2000.

Office of Water. 1997. Guidelines for preparation of the comprehensive state water quality
assessments. EPA-841-B-97-00. U.S. Environmental Protection Agency, Washington D.C.

Paerl, H.W., R.S. Fulton, III, P.H. Moisander, and J. Dyble. 2001. Harmful freshwater algal blooms
with an emphasis on cyanobacteria. The Scientific World. 2001(1):76-113.

Raval, Shardul. 2004. NC Division of Forest Resources. Personal Communication.

Redfield, A. 1958. The biological control of chemical factors in the environment. Am. Sci. 45:205-
221.

Research Triangle Institute (RTI). 2002a. Point Source Nutrient Delivery Model for Jordan
Reservoir. Research Triangle Institute, Research Triangle Park, NC. January 23, 2002

Research Triangle Institute (RTI). 2002b. Nitrogen and Phosphorus Delivery From Small
Watersheds to Jordan Reservoir. Prepared for Tetra Tech, Inc. and the North Carolina Division of
Water Quality By Research Triangle Institute, Research Triangle Park, NC. June 30, 2002

Schindler, D.W. 1977. Evolution of phosphorus limitation in lakes. Science. 46:260-262.

Smith, R.A., G.E. Schwarz, and R.B. Alexander. 1997. Regional interpretation of water-quality
monitoring data. Water Resources Research, 12:2781-2798.

Smith, V.H. 1983. Low nitrogen to phosphorus ratios favor dominance by blue-green algae in lake
phytoplankton. Science. 221: 669-671.

Smith, V. H. 2001. Blue-green Algae in Eutrophic Fresh Waters. Lakeline. 21(1):34-37.

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

B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 59
Tetra Tech. 2001. Jordan Reservoir Nutrient Response Modeling Project: Existing Data
Memorandum. Prepared for Triangle J Council of Governments and the Jordan Reservoir Project
Partners by Tetra Tech, Inc. Research Triangle Park, NC. August 2001.

Tetra Tech. 2002. Jordan Reservoir Nutrient Response Model. Prepared for the Jordan Reservoir
Project Partners by Tetra Tech, Inc., Research Triangle Park, NC. November 2002.

Tetra Tech. 2003a. B. Everett Jordan Reservoir Nutrient Response Model Enhancement. Prepared
for the North Carolina Division of Water Quality by Tetra Tech, Inc., Research Triangle Park, NC.
Final - September 2003.

Tetra Tech. 2003b. B. Everett Jordan Reservoir TMDL Watershed Model Development. Submitted
to NC Division of Water Quality. November 2003.

Tetra Tech. 2004. Memorandum to NC DWQ from Jon Butcher. Subject: Jordan Reservoir
Nutrient Response Model Uncertainty. Date: 7/26/04

Thomann, R.V. and Mueller, J.A. 1987. Principles of Surface Water Quality Modeling and Control.
Harper and Row, New York, NY.

Triangle J Council of Governments (TJCOG). 2005. Jordan Lake Stakeholder Project. Final
Project. Research Triangle Park, NC

U.S. Environmental Protection Agency (USEPA) 1985. Rates, constants, and kinetics formulations
in surface water quality modeling (II ed.). Athens, GA: EPA-600-3-85-040.

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

U.S. Environmental Protection Agency (USEPA). 1993. Statistical Methods for the Analysis of
Lake Water Quality Trends. EPA 841-R-93-003. Office of Water, Washington D.C.

U.S. Environmental Protection Agency, Federal Advisory Committee (FACA). Draft final TMDL
Federal Advisory Committee Report. 4/28/98.

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

U.S.Environmental Protection Agency (USEPA) 2000b. Implementation Guidance for Ambient
Water Quality Criteria for Bacteria - 1986. DRAFT. Office of Water. EPA-823- D-00-001.

U.S. Environmental Protection Agency (USEPA). 2000c. Nutrient Criteria Technical Guidance
Manual. Lakes and Reservoirs. First Edition. Office of Water, Washington D.C. EPA-822-B00-
001.
B. Everett Jordan Reservoir Phase I Nutrient TMDL – Final

DWQ Modeling & TMDL Unit 60

U.S.Environmental Protection Agency (USEPA). 2003. Letter from Mr. Andrew Bartlett, USEPA
to Ms. Michelle Woolfolk, NCDWQ. November 23, 2003. Subject: Application of chlorophyll a
criterion in Jordan Reservoir to address nutrient enrichment.

U.S. Geological Survey (USGS). 1992. Techniques of Water Resources Investigations of the
United States Geological Survey. Book 4. Hydrologic Analysis and Interpretation. Chapter A3.
Statistical Methods in Water Resources. by D.R. Helsel and R.M. Hirsch.

Vander Borgh, Mark. 2003. Personal communication. NC Department of Environment and Natural
Resources. Division of Water Quality. Environmental Sciences Branch.

Walker, W.W., Jr. 1987. Empirical Methods for Predicting Eutrophication in Impoundments.
Report 4-Phase III: Applications Manual. Technical Report E-81-9. U.S. Army Corps of Engineers,
Waterways Experiment Station, Vicksburg, MS.

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Appendix I. Supporting documents for the Jordan Reservoir Phase I
TMDL

The following titles are available for download at
http://h2o.enr.state.nc.us/tmdl/SpecialStudies.htm#Jordan.

Jordan Reservoir Watershed Model Development
Jordan Reservoir Nutrient Response Model Enhancement
Jordan Additional Target Analysis and Figures
Nitrogen and Phosphorus Delivery from Small Watersheds to Jordan Reservoir
Point Source Delivery Model for Jordan Reservoir
Jordan Reservoir Nutrient Response Model
Jordan Reservoir Nutrient Response Modeling Project: Existing Data Memorandum
Jordan Reservoir Nutrient Response Model Uncertainty

Additional project information is available at
http://www.tjcog.dst.nc.us/regplan/jorlkstk.htm#tabcont

In particular, the Jordan Lake Stakeholder report is available at
ftp://ftp.tjcog.org/pub/jorlake/jlsprep1.pdf
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Appendix II. EPA letter to DWQ dated November 23, 2003
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Appendix III. Volume-weighted statistics for the Jordan Reservoir
nutrient response model

The following is taken from an analysis by Tetra Tech (March 29, 2004).

Results are provided for aggregated segments 1-4 and aggregated segments 14- 15. Accomplishing this
required calculation of volume-weighted concentrations for each observation date. As not all stations are
present with valid data on all dates, weighting was performed over the set of stations that are available on
each date. Volume-weighted predictions from the model were then retrieved for the matched set of dates.

In addition to volume weighting, the statistics calculated differ from those presented in the two model
calibration reports in the following respects:
• Statistics for chlorophyll a are provided in relation to the observed values. That is, the model
results in segments 4, 14, and 15 are corrected for depth support, rather than correcting the
observed values, as was done previously.
• The depth correction factor for segment 4 was set at the revised value of 0.84, as described in
Table 11 of the B. Everett Jordan Lake Nutrient Response Model Enhancement report of
September 2003.
• Observed data were re-accessed from the most up-to-date spreadsheets provided by DWQ. This
resulted in the identification of several valid data points that were omitted from the previous
statistical tabulation.

Reported non-detects were set at one half the quantification limit for the statistical analysis. However,
observations with non-detects at abnormally high detection limits were eliminated from the analysis.
Results for TN, TP, and chlorophyll a are provided in Table 1. Statistics are provided both with and
without 2000. As noted previously, 2000 results are believed to be less reliable due to a shortage of
tributary monitoring data in this year.
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Appendix IV. TMDL summary sheet

Summary Sheet
Total Maximum Daily Load (TMDL)

1. 303(d) List Information

State: North Carolina

County: Alamance, Caswell, Chatham, Durham, Forsyth, Guilford, Orange, Randolph, Rockingham, and
Wake

Major River Basin: Cape Fear River Basin

Watershed: Upper New Hope Creek, Lower New Hope Creek, and Haw River Arms of B. Everett Jordan
Reservoir (Jordan Lake)

303(d) Listed Waters (North Carolina)
Name of stream Description Class Index # Subbasin Acres
Morgan Creek From Chatham County SR
1726 (Durham County SR1109)
to New Hope Creek Arm of
New Hope Creek River Arm of
B. Everett Jordan Reservoir
WS-IV
NSW CA
16-41-2-(9.5) 30605 851
New Hope
Creek
From a point 0.8 mile
downstream of Durham County
SR 1107 to confluence with
Morgan Creek Arm of New
Hope River Arm of B. Everett
Jordan Reservoir
WS-IV
NSW CA
16-41-1-(14) 30605 1377
New Hope
River Arm of B.
Everett Jordan
Reservoir
From source at confluence of
Morgan Cr and New Hope Cr.
Arms of B. Everett Jordan
Reservoir (an east-west line
across the southern tip of the
formed peninsula) to Chatham
County SR 1008
WS-IV B
NSW CA
16-41-(0.5) 30605 1205
New Hope
River Arm of B.
Everett Jordan
Reservoir
From Chatham County SR
1008 to Haw River Arm of B.
Everett Jordan Lake
WS-IV B
NSW CA
16-41-(3.5)a 30605 5673
Haw River From a point 0.5 mile
downstream of U.S. Hwy. 64 to
approximately 1.0 mile below
US Hwy 64
WS-IV
NSW CA
16-(37.3) 30604 53
Haw River Arm
of B. Everett
Jordan
Reservoir
From a point 1.0 mile
downstream of U.S. Hwy. 64 to
dam at B. Everett Jordan Lake
WS-IV B
NSW CA
16-(37.5) 30604 1392
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Constituents of Concern: Total nitrogen, total phosphorus, and chlorophyll a

Designated Uses: Biological integrity, aquatic life propagation, secondary and primary recreation, and
water supply

Applicable Water Quality Standards for Class C Waters in NC:

Chlorophyll a (corrected): not greater than 40 ug/L for lakes, reservoirs, and other waters subject
to growths of macroscopic or microscopic vegetation not designated as trout waters, and not
greater than 15 ug/L for lakes, reservoirs, and other waters subject to growths of macroscopic or
microscopic vegetation designated as trout waters (not applicable to lakes and reservoirs less than
10 acres in surface area).

2. TMDL Development

Development tools: EFDC, WASP, Jordan Reservoir Point Source Delivery Model, GWLF

Critical condition: The TMDL has been determined using the average of a 5-year simulation (1997-2001)
covering a wide range of hydrologic conditions with three years that were drier than normal. The TMDL
is based on meeting the criterion exceedance frequency of 10% during the period from May through
September.

Seasonality: Seasonal variation in hydrology, climatic conditions, and watershed activities are
represented through the use of a continuous flow gage and the use of all readily available water quality
data collected in the watershed.

3.0 Allocation Watershed/Stream Reach

3.1 Upper New Hope Arm

Total Nitrogen
Percent reduction: 35%
Total maximum daily load (TMDL): 641,021 lbs/yr
Continuous waste load allocation (WLA): 336,081 lbs/yr
LA plus WLA-SW: 304,940 lbs/yr
WLA-SW: 35% reduction
Load allocation (LA): 35% reduction

Total Phosphorus
Percent reduction: 5%
Total maximum daily load (TMDL): 82,883 lbs/yr
Continuous waste load allocation (WLA): 23,108 lbs/yr
LA plus WLA-SW: 59,775 lbs/yr
WLA-SW: 5% reduction
Load allocation (LA): 5% reduction
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3.2 Lower New Hope Arm

Total Nitrogen
Percent reduction: 0% (a)
Total maximum daily load (TMDL): 221,929 lbs/yr
Continuous waste load allocation (WLA): 6,836 lbs/yr
LA plus WLA-SW: 215,093 lbs/yr
WLA-SW: 0% reduction
Load allocation (LA): 0% reduction

Total Phosphorus
Percent reduction: 0%
Total maximum daily load (TMDL): 26,574 lbs/yr
Continuous waste load allocation (WLA): 498 lbs/yr
LA plus WLA-SW: 26,076 lbs/yr
WLA-SW: 0% reduction
Load allocation (LA): 0% reduction

(a) Provides a loading cap equal to 1997-2001 baseline nutrient loads.

3.3 Haw River Arm

Total Nitrogen
Percent reduction: 8%
Total maximum daily load (TMDL): 2,567,000 lbs/yr
Continuous waste load allocation (WLA): 895,127 lbs/yr
LA plus WLA-SW: 1,671,873 lbs/yr
WLA-SW: 8% reduction
Load allocation (LA): 8% reduction

Total Phosphorus
Percent reduction: 5%
Total maximum daily load (TMDL): 359,641 lbs/yr
Continuous waste load allocation (WLA): 106,001 lbs/yr
LA plus WLA-SW: 253,640 lbs/yr
WLA-SW: 5% reduction
Load allocation (LA): 5% reduction

WLA-WW = wasteload allocation for wastewater facilities
LA = load allocation for nonpoint sources
WLA-SW = wasteload allocation for permitted stormwater

Margin of Safety: This TMDL utilizes an explicit margin of safety (MOS) applied to the water quality
criterion. The frequency of exceeding the criterion (40 ug/L) has been reduced from 10% to 8%. In
addition, 4 of 5 years (1997-2000) of chlorophyll a data used for model calibration represent uncorrected
chlorophyll a, which is a conservation estimate of corrected chlorophyll a.
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4. Public Notice Date: April 1, 2007 - May 15, 2007

5. Submittal Date: September 12, 2007

6. Establishment Date:

7. Endangered Species (yes or blank):

8. EPA Lead on TMDL (EPA or blank):
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Appendix V. WLA calculations for the Upper New Hope and Haw River
Management Areas

The following spreadsheets detail the calculations involved in determining the WLAs of this TMDL.
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Appendix VI. DWQ responsiveness summary for public comments on the
Jordan Reservoir Phase I TMDL

The B. Everett Jordan Reservoir, North Carolina Phase I Total Maximum Daily Load was public noticed
in the relevant counties on 4/1/07 in four local newspapers (The Durham Herald-Sun, the Winston-Salem
Journal, the Greensboro News & Record, and the Raleigh News & Observer). The TMDL was also
public noticed through the North Carolina Water Resources Research Institute email list serve. Finally,
the TMDL was available on DWQ’s website http://h2o.enr.state.nc.us/tmdl/ during the comment period.
The comment period lasted 45 days from April 1, 2007 until May 15, 2007. DWQ received ten public
comments to the draft TMDL. Specific commenters are listed below.

Glen Whisler, Durham County
Stephen Shoaf, City of Burlington
Sean Brogan, NCDFR
Sheri Bryant, NC Wildlife Resources Commission
Gregory Thorpe, NCDOT
Elaine Chiosso, Haw River Assembly
James Gray and Henry Randolph, Society of American Foresters, Sandhills Chapter
Howard “Bud” Taylor, Central Carolina Forestry Club
Loren Hintz, Private Citizen
John Cox, City of Durham

Many of the comments received were related to the Jordan Reservoir Nutrient Management Strategy (the
Jordan Rules) and were not relevant to the TMDL document. These comments will be forwarded to the
DWQ Non-Point Source Planning Unit for incorporation into the Jordan Rules public comment
documentation.

DWQ response to comments on the Jordan Lake Phase I TMDL document follows.

COMMENT: Several commenters expressed support for the proposed nutrient reduction targets detailed
in the TMDL.

RESPONSE: DWQ appreciates support for the nutrient reduction targets.

COMMENT: Three commenters noted that on page v, the note that “DWQ would protect existing
riparian buffers” is inconsistent with the proposed regulations 15A NCAC 02B .0267 in which the local
governments are responsible for protecting riparian buffers.

RESPONSE: This is true. This sentence was revised as follows.

DWQ would require local governments to protect riparian buffers.

COMMENT: On page v, the note that “All local governments would meet NPDES Phase II stormwater
requirements of S1210”, is incorrect as all local governments, such as the County of Durham, are not
covered by the Phase II requirements.
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RESPONSE: This is true. The note was revised to provide further clarification on Phase II requirements
as follows.

• Stormwater:
o New development in unincorporated areas of all counties except Caswell and
Rockingham are subject to the post-construction stormwater measure of the
NPDES Phase II requirements and are permitted by DWQ beginning July 1, 2007
o Seventeen of the twenty six municipalities in the watershed were issued permits by
December 2005 to implement all six measures of the Phase II requirements, either
alone or as part of another MS4's permit, and were required to begin implementing
post-construction permitting under those permits by December 2007.
o All local governments would achieve stormwater N and P export performance
goals from all new and existing development.

COMMENT: Two commenters believe that the TMDL Draft and Strategy should have been completed
including an atmospheric deposition evaluation, and considering the strategy of improved air quality.

RESPONSE: It is true that atmospheric deposition is a source of nutrients in the Jordan Lake watershed.
The nutrient load associated with atmospheric deposition is accounted for in the TMDL as part of the non-
point source load. The Jordan Lake watershed model, used for implementation of this TMDL, accounted
for atmospheric deposition of nutrients in urban areas by using a “build up” rate (Tetra Tech, 2003).
These loading rates were based on annual stormwater unit loading rates developed for the Town of Cary,
NC in close proximity to Jordan Lake. Unfortunately, a more sophisticated approach to accounting for
atmospheric deposition in the Jordan Lake watershed is not feasible at present since the scientific
understanding of atmospheric deposition of nutrients is not yet adequate to be useful in modeling the
spatial and temporal variation of deposition in watershed modeling and there are currently no deposition
monitoring sites in the Jordan Lake watershed. DWQ intends to stay abreast of the latest research in
atmospheric deposition and will incorporate these findings in adaptive management strategies as they
emerge. DWQ is not pursuing an air quality strategy for this TMDL, but encourages local governments to
pursue improvements in air quality to address nutrient loading to the lake.

COMMENT: Design changes for the road crossings should be considered.

RESPONSE: Road causeways do have the potential to affect the spatial distribution of nutrient
concentrations in Jordan Lake, and removal of these causeways may improve water quality in terms of
chlorophyll a concentrations in lake segments upstream. However, this proposal has the potential to
cause additional impairments or worsen existing impairments in lake segments downstream of the present
road causeways. Further, segments of the Cape Fear River just 4 miles downstream of the dam at Jordan
Lake are currently listed as impaired for chlorophyll a standard exceedances on the 2006 303(d) list.
While this proposal may have some merit, it is clear that we should proceed with caution in considering a
strategy that could affect water quality downstream. At this point, DWQ believes we need to move
forward with the current TMDL and nutrient management strategy, and if further actions are required to
improve water quality in the lake as identified in the adaptive management strategy, alternatives such as
removing road causeways will be considered.

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The Jordan Lake TMDL does not prohibit the pursuit of this strategy. However, since the lake is
impaired for chlorophyll a and is listed on the 303(d) list, a TMDL must be determined to address this
impairment pursuant to the Clear Water Act. A TMDL addresses pollutant loads and reductions of those
loads, it does not address other management alternatives such as modifications to road crossings.

COMMENT: Page iii Senate Bill 1366 actually replaced the requirements of House Bill 515
regarding what would be required based on the results of the nutrient response model. The limits of 5.5
mg/L of TN and the 2.0 mg/L of TP did not apply in SB 1366. It did establish a compliance period as
discussed in paragraph 3 of this page.

RESPONSE: The third paragraph on page iii was revised as follows.

The Clean Water Responsibility Act of 1997 (often referred to as House Bill 515) included legislation to
further address water quality problems in NSW waters (NC General Statute 143-215.1(c1) to (c5)). The
act set total nitrogen (TN) and total phosphorus (TP) NPDES permit limits for facilities discharging
greater than 0.5 MGD into the Jordan Reservoir/Haw River watershed. A 5-year compliance period for
limits of 5.5 mg/L of TN and 2.0 mg/L of TP was established for qualifying wastewater facilities. The
act provides conditions for an extended compliance period, including the development of a calibrated
nutrient response model and the development of plans to optimize nutrient removal at the wastewater
facility. The act also established that a calibrated nutrient response model may be developed by DWQ in
conjunction with affected parties, and the model may indicate the required TN and TP concentration
limits for dischargers greater than 0.5 MGD are different from those listed above. In 1998, Senate Bill
1366 allowed the Environmental Management Commission (EMC) to extend the compliance deadline for
these dischargers if additional time was needed to develop a calibrated nutrient response model. The
municipalities of Greensboro, Mebane, Reidsville, Graham, Pittsboro, and Burlington, and the Orange
Water and Sewer Authority (OWASA) were granted a compliance extension in 1999. Facilities that did
not seek compliance extensions were the City of Durham/Durham South WWTP and the Durham County/
Triangle WWTP. Conditions associated with the extended compliance period were achieved and the
calibrated nutrient response model was accepted by the Water Quality Committee (WQC) of the
Environmental Management Commission EMC in July 2002.

COMMENT: The lake was listed as impaired for chlorophyll a, however there has not been a
determination that the intended uses are not being met. The statement that the TMDL is intended “…to
estimate the allowable pollutant loads and allocate the loads to known sources so that the waterbody may
be restored to its intended uses...” (paragraph 4) implies a curtailment of an intended use, and this has
not been demonstrated.

RESPONSE: EPA requires states to use the numeric water quality standard as endpoints for TMDLs
when such a standard exists (EPA 1999). North Carolina has a chlorophyll a standard that is used both to
conduct use support and to set TMDL endpoints. DWQ cannot vary from this water quality standard
when developing target loads and concentrations.

COMMENT: Page v The nonpoint source strategy includes provisions for agriculture that are
not controlled by NCDENR/DWQ.

RESPONSE: This is true. The agricultural operations bullet was revised as follows.

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All agricultural operations collectively meet N and P export performance goals as implemented by local
committees (EMC has no regulatory authority over this management area);

COMMENT: In paragraph 2 there is an omission in the discussion of SB 1366. The way this paragraph
is written, it leads the reader to conclude that the HB 515 TN and TP limits were/are still in effect. There
is no mention that the calibrated nutrient response model would be used to generate new nutrient limits in
the basin.

RESPONSE: Revised paragraph as follows.

The Clean Water Responsibility Act of 1997 (CWRA, often referred to as House Bill 515) included
legislation to further address water quality problems in NSW waters (NC General Statute 143-215.1(c1)
to (c5)). The act set total nitrogen (TN) and total phosphorus (TP) NPDES permit limits for facilities
discharging greater than 0.5 MGD into the Jordan Reservoir/Haw River watershed. A 5-year compliance
period for limits of 5.5 mg/L of TN and 2.0 mg/L of TP was established for qualifying wastewater
facilities. The act also established that a calibrated nutrient response model may be developed by DWQ
in conjunction with affected parties, and the model may indicate the required TN and TP concentration
limits for dischargers greater than 0.5 MGD are different from those listed above. Amendments to the act
approved in 1998 (referred to as Senate Bill 1366) provided a compliance extension to the nutrient limits,
with conditions. Those wastewater facilities granted a compliance extension by the Environmental
Management Commission were required to develop a calibrated nutrient response model, evaluate and
optimize the operation of all facilities to reduce nutrient loading, and evaluate methods to reduce nutrient
mass loading to NSW waters. The municipalities of Greensboro, Mebane, Reidsville, Graham, Pittsboro,
and Burlington, and the Orange Water and Sewer Authority (OWASA) were granted the compliance
extension by the Environmental Management Commission in April 1999. This collective group is
referred to as the Project Partners in subsequent chapters. Facilities that did not seek compliance
extensions are the City of Durham/ Durham South WWTP and Durham County/ Triangle WWTP.

COMMENT: Page 7 The land use data seems to be dated and much of the 1992 NLCD is now
over 15 years old.

RESPONSE: This is true. However, because the model baseline period was 1997-2001, DWQ believes
that the 1992 NLCD data are appropriate for this study.

COMMENT: Page 9 The discussion of the 40 ug/L chlorophyll a standard does not include
discussion of the confusion about the standard. This standard was developed using an older analytical
method (spectrophotometric method) and now the State is using a fluorometric method that is more
sensitive by a factor of about 2X. Thus it appears that the 40 ug/L limit being enforced is equivalent to
what was a 20 ug/L concentration.

RESPONSE: The chlorophyll a standard was not developed based on any one analytical method. It was
developed through consensus with researchers and managers in the late 1970's. The state was using an
EPA approved spectrophotometric method when the chlorophyll a standard was adopted and then moved
to using an EPA approved fluorometric method in 1981.

The US EPA (under contract # 68-C-04-006) published a summary of literature comparisons for all
analytical methods. This report, entitled “Summary of literature Comparing Methods for the Analysis of
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Chlorophyll in water Samples” noted differences in predicted analysis – but, most predictions were in the
range of 10% overestimation when spectrophotometric methods were used. To follow up on the literature
search, US EPA region IV – conducted a study of 3 labs using split sample and the fluorometric method
results indicated no large discrepancies. They completed their review by using 5 different methods and 2
laboratories. Only results from the HPLC methods indicated significantly lowered responses with the
split sample results.

DWQ continues to work with certified laboratories to ensure that data used for assessment purposes are
comparable.

COMMENT: Page 10 In the first paragraph, the final sentence states that the USEPA Region 4
supports the application of the 40 ug/L standard as a seasonal standard with less than 10% frequency of
exceedance. In some instances this standard was applied using an annual interpretation. Upon reading
the letter from Region 4, it seems that they cautioned NCDENR that this is not how the standard was
applied in other circumstances, but that it could be applied that way if the State chose to do so. The final
determination was left to the State’s discretion.

RESPONSE: The load reductions proposed in the Jordan Lake TMDL are based on a 10% chlorophyll a
standard exceedance frequency during summer months (i.e. June – September). Other TMDLs (Neuse
Estuary) were based on annual exceedance rather than summer months, while others (Robeson Creek) are
based on summer months like the Jordan Lake TMDL. The EPA memo dated 11/23/03 (Appendix II of
TMDL document) supports using summer months only, noting that “The use of non-growing season
chlorophyll a data would tend to mask the growing season impact of nutrient enrichment in reservoirs
such as Jordan Lake” and that considering the summer season only will be“…more likely to ensure
attainment of the narrative criteria requiring that a balanced and indigenous community can thrive under
the most critical conditions, which in this case occurs during the growing season for the lake.” EPA
guidance (Protocol for Developing Nutrient TMDLs, 1999) states that “an approvable TMDL will need to
include…consideration of seasonal variation and high and low flow conditions such that water quality
standards for the allocated pollutant will be met during all design environmental conditions.”

COMMENT: Page 10 An additional monitoring effort was conducted by the UNC-CH Department
of Environmental Sciences and Engineering under contract with the Army Corps of Engineers.

RESPONSE: We added UNC-Chapel Hill to list of previous studies.

COMMENT: It should be pointed out that there were analytical problems with the chlorophyll a
analyses, and the region was experiencing a drought during 1999 – 2002 that was cumulative in its
effects and became severe.

RESPONSE: The chlorophyll a data issues are discussed in a later section of the Draft TMDL document
(see section 6.6.1- Data Uncertainty). Due to analytical problems, laboratory samples for phaeophytin-
corrected chlorophyll a processed in 1997-2000 were unusable (uncorrected chlorophyll a data were still
valid). Data collected in 2001 did not have this problem. DWQ used the uncorrected chlorophyll a
concentrations for model calibration during these years. The ratio between corrected and uncorrected
chlorophyll a concentrations was found to be very close to unity during July-September (Tetra Tech,
2003), increasing during the remaining months. Since the nutrient load reductions proposed in the TMDL
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document are based on summer months, DWQ believes that using the uncorrected chlorophyll a data
during 1997-2000 to establish load reduction targets is appropriate.

The low rainfall in 2000 and 2001 are discussed in a later section of the Draft TMDL document (see
section 6.3- Critical Conditions). The model simulation period consisted of a wet year (1998) a normal
year (1997) and three years that were drier than normal, although each with different characteristics
(1999-2001). However, the seasonal analysis shows that inflows and precipitation were not
extraordinarily low, except for local precipitation during the summer of 1999. The drought, in terms of
water supply availability, was the cumulative effect of several years of below normal precipitation and
flow. Conditions, when examined on a seasonal basis, were not so extraordinarily rare as to be
unrepresentative of the expected range of lake response.

COMMENT: Tetra Tech acknowledged the short-comings of the data and subsequent model and made
suggestions of how to improve model performance. They recognized the complexity of the system and the
difficulty in modeling it. The suggested improvements included better spatial and temporal coverage
during sampling events. To date this has not been done.

RESPONSE: As part of the original Jordan Lake modeling report, Tetra Tech presented
recommendations for additional monitoring in Jordan Lake and its tributaries (Tetra Tech, 2002). These
were presented for “further refinement of the Jordan Lake Nutrient Response Model.” In these
recommendations, Tetra Tech acknowledged that “the [2000-2001] data provided good coverage both
temporally and spatially” but that “it would be desirable to improve temporal coverage for laboratory
parameters even at the expense of less spatial coverage.”

Any mathematical model of a natural system has some level of uncertainty and can be improved upon
given sufficient time and financial resources. DWQ believes that the Jordan Lake Nutrient Response
Model in its current form provides an adequate representation of nutrient response in the lake and that it
can be used to evaluate nutrient management scenarios such as those presented in this TMDL document.
Section 6.6.2- Lake Model Uncertainty provides additional discussion on this issue.

DWQ will continue to monitor water quality in the lake to gauge progress toward attainment of the
chlorophyll a standard through adaptive management.

COMMENT: Pages 13, 14, and 15 The data sources should be identified for these graphs.

RESPONSE: The data were collected by DWQ. This information was added to the figure captions.

COMMENT: Page 16 A statement should acknowledge which data in Table 2 contains estimated
(uncorrected) data and the data source.

RESPONSE: Added “Chlorophyll a data from 9/96-1/01 are uncorrected for phaeophytin
concentrations” to the table caption.

COMMENT: Page 18 In Table 4. the NPDES permit number for the City of Burlington South
Burlington WWTP is incorrect. The correct permit number is NC0023876.

RESPONSE: The permit number was changed to read NC0023876.
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COMMENT: Page 21 The last paragraph of this page discusses the Phase II stormwater
permitting program. It should be pointed out that the Phase II programs have not been fully implemented
and thus we cannot judge their impacts on future water quality.

RESPONSE: The point of this paragraph is to simply discuss the background of Phase II and to list the
permits issued in the Jordan Lake watershed. It is true that the program has not been completely
implemented and it will remain to be seen the magnitude of water quality improvements achieved as a
result of this program. DWQ will continue to monitor water quality in the Jordan Lake watershed to help
assess the impact of the stormwater permitting process.

COMMENT: Page 22 The second paragraph under this section is either confusing or misleading.
The statement that “…Agriculture makes up only approximately 4% of land use (Figure 3)” is not
correct. Agriculture makes up 4% of the land use in the Upper New Hope Arm, 24% in the Haw River
Arm, and 20% of the land use in the entire watershed based on Figure 3.

RESPONSE: The paragraph was revised as follows.

Agricultural and urban land uses can contribute considerable amounts of nutrients due to fertilizer use. In
the Upper New Hope Management Area, agriculture makes up only approximately 4% of land use (Figure
3). The Upper New Hope Arm is developed more intensely than the Haw River Arm, which has 24%
agricultural land use. Impervious surfaces associated with developed areas increase the quantity and
velocity of runoff and associated contaminants.

COMMENT: Page 23 In the third paragraph the discussion of sewer service should indicate that
the percentages presented represent the population served and not the land area (ie. 62% of the
population of Alamance County is served by sewer). I think that was intended but not 100% clear.

RESPONSE: The paragraph was revised as follows.

No comprehensive, up-to-date coverage of sewer service areas is available for the entire watershed. Data
from the 1990 census indicate the following sewer usage proportions (NC DEH, 1999). :
• Alamance County, 62% of population sewer usage,
• Chatham County, 33% of population sewer usage,
• Durham County, 91% of population sewer usage, and
• Orange County, 68% of population sewer usage.

COMMENT: Page 26 Header uses the word “validation” which is incorrect. The model has not
been validated. The discussion that followed this header points out the problems with calibration, poor
model fit, and the issues surrounding seasonal fit. There were very few data points outside of the summer
growing season, so it is not surprising that the results were inconsistent for the fall data.

RESPONSE: Typically, the output of water quality models is compared to measured data so that model
input parameters can be adjusted to achieve the best agreement between simulated and measured water
quality data. This process is known as calibration. After calibration, model output is compared to another
set of measured data (from a different time period than the data used for calibration) in a process called
validation.
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The initial Jordan Lake Nutrient Response Model was calibrated using data from 1997-1999. When the
Upper New Hope Arm of the lake was listed as impaired on the 303(d) list in 2002, it was decided to use
the additional monitoring data collected in 2000 and 2001 to complement the initial modeling study for
TMDL development. It was found that the initial model input parameters used for the 1997-1999 time
period did not provide satisfactory results for 2001 (the model was not calibrated for 2000 because there
were limited tributary data that year). This may have been due in part to using uncorrected chlorophyll a
in 1997-1999 and corrected data in 2001. A constrained recalibration was undertaken to find a set of
model input parameters that would allow the best compromise between both sets of data. The recalibrated
model used monitoring data from 2000 for validation.

It is true that there were few monitoring data points that fell outside the summer season and that model fit
with measured data outside the summer season is poor. However, this TMDL is based on the percentage
of chlorophyll a standard exceedances during the summer season, where there are many monitoring data
points and where the model fit with measured chlorophyll a concentrations was the best.

COMMENT: Page 31 In Table 7. the NPDES permit number for the City of Burlington South
Burlington WWTP is incorrect. The correct permit number is NC0023876. Also, the average annual
delivered load for TP for the South Burlington WWTP and the Reidsville WWTP are incorrect. There
appears to be a decimal instead of a comma in those two numbers (typo’s).

RESPONSE: The permit number for the Burlington South WWTP was corrected. The decimal was
replaced with a comma for the TP average annual delivered load for Burlington as well as Reidsville.

COMMENT: Page 37 The first sentence in this section should expressly state that the nitrogen and
phosphorus loads shown in Figure 11 are for the Upper New Hope Arm.

RESPONSE: The first sentence was revised as follows.

Sources of the nonpoint nitrogen and phosphorus load in the Upper New Hope Management Area are
summarized in Figure 11.

COMMENT: Page 43 Figure 13 should use the same scale of 1:1 TN:TP like the Figure 12. This
would present a truer picture of the two arms of the lake. It is misleading to present Figure 13 with a
scale of 1.5:1.5.

RESPONSE: Figure 13 was revised to show a scale of 1:1 TN:TP similar to that of Figure 12.

COMMENT: Page 46 In the first line on this page there is a typo with the word statistics used
twice.

RESPONSE: This has been corrected.

COMMENT: Page 47 It is important to note that blue green algae blooms occur in other
waterbodies and some have no direct discharges of pollutants.

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RESPONSE: The TMDL document does not suggest that blue green blooms only occur in waterbodies
with direct discharges; therefore no changes to the document were made.

COMMENT: Page 50 In the next to last paragraph on this page, the flow used for determining the
allocation should be the flow related to the baseline nutrient determination. It doesn’t make sense to use
flows from 2004 and nutrient data from the 1997-2001 baseline period.

RESPONSE: The discharger permitted flow is simply a means of dividing up the waste load allocation
established by this TMDL among dischargers in the Jordan Lake watershed. The permitted flow for 2004
was used because there were permitted WWTP expansions already underway or completed during 2004
and 2005, after the 1997-2001 baseline period. Using the 2004 permitted flows thus accounted for these
expansions and represents the most current representation of point source dischargers to Jordan Lake.
These are the correct flows to use for allocation purposes.

COMMENT: Three commenters believed that the statement “DWQ would work with DFR to require
forestry pre-harvest notification (EMC has no control over this management area)” should be deleted
from the document.

RESPONSE: This statement was inadvertently left in the TMDL from a previous version. The statement
was removed from the TMDL document.

COMMENT: Two commenters expressed concern that reductions in chlorophyll a may affect the
productivity of the lake for recreational fishing.

RESPONSE: It is true that algal communities are the foundation of the aquatic food web in Jordan Lake,
and that reductions in algal concentrations below a certain level could affect the productivity of the Jordan
Lake fishery. DWQ acknowledges the need for a minimum level of chlorophyll a concentration in the
lake. Model results indicate that mean summer chlorophyll a concentrations will remain above the 15
µg/l minimum concentration recommended by the NC Wildlife Resources Commission.

COMMENT: The DOT was not invited to participate in the stakeholder process to develop the Jordan
Reservoir TMDL and management strategy described on page 56 of the TMDL report.

RESPONSE: This was an oversight by DWQ and the Triangle J Council of Governments who facilitated
the stakeholder process for the development of the Jordan Lake Nutrient Management Strategy, and it was
completely unintentional. DWQ apologizes for not specifically including DOT in the stakeholder
process.

COMMENT: The DOT is concerned that DWQ made no effort to quantify nutrient loads from DOT
facilities in the TMDL.

RESPONSE: DWQ assumes that DOT is referring to nutrient loads as they pertain to their MS4 permit.
Permitted stormwater loading (WLA-SW) was not explicitly separated from non-permitted loading from
non-point sources (LA) in this TMDL (see Section 7, page 49). As such, the percent reduction in nitrogen
and phosphorus loads for all MS4s is the same as that indicated in the TMDL for non-point source loads.
There are 20 stormwater MS4 permits in the Jordan Lake watershed. DWQ did not attempt to quantify
nutrient loads from any of these individual permitees.
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COMMENT: The watershed model is poorly explained and documented in the TMDL report.

RESPONSE: The watershed model was not used in the calculation of total maximum daily loads to
Jordan Lake, rather it was used to estimate nutrient loading by point and non-point sources from 14-digit
HUCs, counties, land uses, etc. for the implementation of the nutrient reductions proposed in this TMDL
document. As a result, DWQ did not go into great detail regarding the development and implementation
of the watershed model in the TMDL document. The DOT is encouraged to refer to the B. Everett Jordan
Lake TMDL Watershed Model Development report (Tetra Tech, 2003) for watershed model details not
presented in the TMDL document. DWQ will provide the DOT with a copy of this report if necessary.

COMMENT: We are not convinced that the requirement for a Margin of Safety for the Jordan Lake
TMDL has been met – since all assimilative capacity has been allocated.

RESPONSE: It is true that all of the available mass loading was allocated to existing facilities with no
additional mass allocations for future discharges or expansions. The TMDL document discusses the
incorporation of an explicit margin of safety used to account for uncertainty in the relationship between
pollutant loads and receiving water quality (Section 6.6, pages 44-45). The margin of safety was
incorporated by reducing the maximum frequency of chlorophyll a exceedances from 10% to 8% when
evaluating nutrient load reduction scenarios. The Jordan Lake Nutrient Management Strategy addresses
future expansions of existing discharges in the watershed such that the total nutrient loading to the lake
will not increase over the 1997-2001 baseline levels.

COMMENT: The goal is to not exceed by more than 10% the chlorophyll a standard for water quality.
If it’s a standard, we do not see how the target includes allowing it to be violated.

RESPONSE: This interpretation of the chlorophyll a standard is also used by DWQ (and supported by
EPA) for use support determination. There can be unforeseen events both natural and human-induced that
could occasionally cause chlorophyll a concentrations to exceed the chlorophyll a standard. Other
TMDLs developed in North Carolina and approved by EPA have had similar interpretations of the
standard (e.g. Neuse Estuary, Roberson Creek).

COMMENT: Two commenters noted that this draft TMDL is proposed for the Jordan Reservoir sub-
basins of the Cape Fear River Basin and that it is not being developed for the remainder of the basin.
They oppose this rule being extended across the remainder of the basin without input from those parties
impacted outside of the Jordan Reservoir sub-basin.

RESPONSE: This TMDL applies only to the Jordan Lake watershed. It does not apply to the entire
Cape Fear River basin.

COMMENT: On page iii, third paragraph, a word is missing that reverses the meaning of the sentence:
“Facilities that did not seeking compliance extension are the City of Durham/Durham South WWTP and
the Durham County/Triangle WWTP…”

RESPONSE: The sentence was revised to read:

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Facilities that did not seek compliance extensions were the City of Durham/Durham South WWTP and
the Durham County/Triangle WWTP.

COMMENT: …From the Cape Fear River Basinwide Water Quality Plan. “DWQ performed a
statistical trend analysis at site BA177 using total nitrogen, total phosphorus and total suspended solids
data collected from 1990 to 2004. There was a significant decrease in total nitrogen of 0.17 mg/l per
year in New Hope Creek. Downward trends were noted for total phosphorus and total suspended solids,
although these trends were not significant.”

RESPONSE: It is true that nitrogen loads have decreased in New Hope Creek, and DWQ appreciates the
efforts of the City of Durham in implementing plant improvements that make this possible. However,
despite reductions in nitrogen loads from New Hope Creek, there are still many instances of exceedance
of the chlorophyll a standard in the New Hope Creek arm of the lake as well as in downstream segments
(see pages13-15). These excursions of the chlorophyll a standard indicate that the reductions in nitrogen
loading in this tributary have not been enough to address the impairment in Jordan Lake and that further
reductions are needed.

COMMENT: The flux software was used to calculate loads into the lake and nonpoint sources loads
were estimated by subtracting the nearby upstream wastewater loads. This appears to over-estimate the
nonpoint source contribution.

RESPONSE: The proportion of nutrient loading to Jordan Lake contributed by non-point sources was
estimated by subtracting the total delivered point source loads to the lake from the total loading to the lake
over the 1997-2001 time period. The total delivered point source loads were estimated using measured
discharger loads adjusted for attenuation in the tributary network. The total loading (point and non-point
source loading) to the lake was estimated using the FLUX software to create a daily time series of nutrient
loading from each of the tributaries to the lake based on measured flow and nutrient concentrations. This
is an accepted means of calculating non-point source loads.