NC0081370_Speculative Limits_20140212

NPDES DOCUMENT :MCANNINO COVER :MEET
NPDES Permit:
NC0081370
Claremont / McLin Creek WWTP
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Correspondence
Owner Name Change
Additional Information Received
Instream Assessment (67b)
Speculative Limits
Environmental Assessment (EA)
Document Date:
February 12, 2014
This document is printed on reuse paper - ignore any
content on the re-szerse side

A A ioiy spc Lifni
ern
ThENR
North Carolina Department of Environment and Na
Division of Water Resources
Pat McCrory Thomas A. Reeder
Governor Director
February 12, 2014
Mr. Guy Slagle, P.E., Project Director
Davis & Floyd
1073 13th Street NE
Hickory, NC 28602
Secs/416We h rl�
ural Resources
John E. Skvarla, III
Secretary
Subject: Speculative Effluent Limits
City of Claremont
McLin Creek WWTP
Permit No. NC0081370
Catawba County
Catawba River Basin
Dear Mr. Slagle:
This letter provides speculative effluent limits for 1.2 MGD at the Claremont McLin Creek
WWTP. The Division received the speculative limits request in a letter dated January 21, 2014.
Please recognize that speculative limits may change based on future water quality initiatives,
and it is highly recommended that the applicant verify the speculative limits with the Division's
NPDES Unit prior to any engineering design work. The Division understands that the
Claremont North WWTP will be decommissioned upon expansion of the McLin Creek WWTP.
Receiving Stream. McLin Creek is located within the Catawba River Basin. McLin Creek
has a stream classification of WS-IV;CA, and waters with this classification have a best
usage for a source of water supply for drinking, culinary, or food -processing purposes in
addition to the uses for aquatic life propagation and maintenance of biological integrity,
wildlife, secondary recreation and agriculture. McLin Creek has a summer 7Q10 flow of 5
cfs, a winter 7Q10 flow of 9 cfs, and an annual average flow of 26 cfs.
McLin Creek is currently listed as an impaired waterbody on the 2012 North Carolina 303(d)
Impaired Waters List for biological integrity. There are no specific permitting strategies for
McLin Creek in the Catawba River Basinwide Water Quality Plan.
Based upon a review of information available from the North Carolina Natural Heritage
Program Online Map Viewer, there are not any Federally Listed threatened or endangered
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Location: 512 N. Salisbury St. Raleigh, North Carolina 27604
Phone: [phone] FAX: [phone]
Internet www.ncwateraualitv.orq
An Equal Opportunity 1 Affirmative Action Employer
No Carolina
aurally

Mr. Guy Slagle
February 12, 2014
Page 2 of 4
aquatic species identified within a 5 mile radius of the proposed discharge location. If there
are any identified threatened/endangered species, it is recommended that the applicant
discuss the proposed project with the US Fish and Wildlife Service to determine whether the
proposed discharge location might impact such species.
Speculative Effluent Limits. Based on Division review of receiving stream conditions and
the Upper Lyle and McLin Creek Water Quality Modeling Analysis prepared by
HydroAnalysis, speculative limits for the proposed expansion to 1.2 MGD are presented in
Table 1. A complete evaluation of these limits and monitoring requirements for metals and
other toxicants, as well as potential instream monitoring requirements, will be addressed
upon receipt of a formal NPDES permit application. Some features of the speculative limit
development include the following:
• BOD/DO/NH3N Limits. The limits for BOD, DO and NH3N are based on the
results of the modeling analysis. The Qua12K model predicted DO concentrations
above the water quality standard maintaining the current concentration limits for
BOD and ammonia.
• Upstream/Downstream Monitoring. Instream monitoring for dissolved oxygen and
temperature is recommended to evaluate the increased discharge impact on the
watershed. Monitoring locations will be determined when the permit is modified to
include the expansion.
TABLE 1. Speculative Limits for
Effluent Characteristic
"
Effluent l is ii& Ons
Monthly Average
' Weed: y Average
'Daily . ximum
Flow
1.2 MGD
BOD5 (April 1- October 31)
8.0 mg/L
12.0 mg/L
BOD5 (November 1- March
31)
16.0 mg/L
24.0 mg/L
NH3 as N (April 1- October
31)
2.0 mg/L
6.0 mg/L
NH3 as N (November 1-
March 31)
4.0 mg/L
12.0 mg/L
Dissolved Oxygen
(minimum)
5.0 mg/L
TSS
30 mg/L
45 mg/L
.
TRC
28 ug/1
Fecal coliform (geometric
mean)
200/100 ml
400/100 ml
Total Phosphorus
Monitor
Total Nitrogen
Monitor
Dissolved Oxygen
Upstream/Downstream monitoring

Mr. Guy Slagle
February 12, 2014
Page 3 of 4
Temperature
Upstream/Downstream monitoring
Chronic Toxicity Pass/Fail
(Quarterly test) 27%
Engineering Alternatives Analysis (EAA). Please note that the Division cannot guarantee
that an NPDES permit for a new or expanding discharge will be issued with these
speculative limits. Final decisions can only be made after the Division receives and
evaluates a formal permit application for the new/expanded discharge. In accordance with
North Carolina Administrative Code 15A NCAC 2H.0105( c), the most environmentally
sound alternative should be selected from all reasonably cost effective options. Therefore,
as a component of all NPDES permit applications for new or expanding flow, a detailed
engineering alternatives analysis (EAA) must be prepared. The EAA must justify requested
flows and provide an analysis of potential wastewater treatment alternatives. A copy of the
Division guidance for preparing EAA documents is attached.
State Environmental Policy Act (SEPA) EA/EIS Requirements. A SEPA EA/EIS document
must be prepared for all projects that: 1) need a permit; 2) use public money or affect public
lands; and 3) might have a potential to significantly impact the environment. For new or
expanding discharges, significant impact is defined as > 500,000 gpd additional flow. Since
the City of Claremenot is proposing an increase in flow >500,000 gpd, the City must
prepare a SEPA document that evaluates the potential for impacting the quality of the
environment. The NPDES Unit will not accept an NPDES permit application for the
expanded discharge until the Division has approved the SEPA document and sent a Finding
of No Significant Impact (FONSI) to the State Clearinghouse for review and comment. A
SEPA Environmental Assessment (EA) should contain a clear justification for the proposed
project. If the SEPA EA demonstrates that the project may result in a significant adverse
effect on the quality of the environment, you must then prepare a SEPA EIS (Environmental
Impact Statement). For projects that are subject to SEPA, the EAA requirements discussed
above will need to be folded into the SEPA document. The SEPA process will be delayed if
all EAA requirements are not adequately addressed. If you have any questions regarding
SEPA EA/EIS requirements, please contact Jackie Roddy with DWR Planning at (919) 807-
6442.
Should you have any questions about these speculative limits or NPDES permitting
requirements, please feel free to contact Teresa Rodriguez at [phone] or Tom Belnick
at [phone].
Respectfully,
atgilittL
om Belnick
Supervisor, NPDES Complex Permitting Unit
Attachment: EAA Guidance Document

Mr. Guy Slagle
February 12, 2014
Page 4 of 4
Hardcopy:
Central Files
NPDES Permit File
Electronic Copy:
US Fish and Wildlife Service, [e-mail]
DWR/Mooresville Regional Office
DWR/SEPA, Jackie Roddy
DWR/Modeling, Kathy Stecker
DWR/Basinwide Planning, Jeff Manning
NPDES Server>Specs

SePC 144' C/i'ir4if/Mtt"1 j.iidl('
Belnick, Tom CawL " gA,Vri
hio
From: Belnick, Tom
Sent: Wednesday, January 22, 2014 4:22 PM
To: Behm, Pamela; Rodriguez, Teresa
Cc: Stecker, Kathy
Subject: FW: Speculative Limits Request, Claremont, NC
Attachments: DENR Speculative Limits Request.pdf
Incoming spec request. Claremont is requesting spec for expansion from current 0.3 MGD up to 1.2 MGD. I'm not sure
if Ken Hickey's QUAL2K model covered a 1.2 MGD discharge?
Teresa- I'm assigning this spec to you. Please coordinate with Pam, who was reviewing the QUAL2K effort. NPDES issued
a previous spec to Claremont dated May 4, 2011 for 0.85 MGD, and at that time we just froze the BOD/NH3 loads due to
instream DO concerns. But now we should be able to utilize the QUAL2K model results. The previous spec does contain
relevant info on receiving stream. Discharge ultimately flows to Lake Norman, so there are no nutrient TMDL
considerations.
Tom Belnick
Supervisor, NPDES Complex Permitting Unit
NCDWR/Water Quality Programs
919-807-6390
E-mail correspondence to and from this address may be subject to the
North Carolina Public Records Law and may be disclosed to third parties
From: Guy Slagle [mailto:gslagleOdavisfloyd.com]
Sent: Tuesday, January 21, 2014 4:38 PM
To: Belnick, Tom
Cc: Doug Barrick; Gene Haynes; Scott Bell; Ken Hickey
Subject: Speculative Limits Request, Claremont, NC
Tom,
Attached is a request for updated Speculative Limits for the McLin Creek WWTP.
If you need further information please let me know.
Guy
Guy E. Slagle, Jr., P.E, R.L.S.
Vice President
D 18 . Davis & Floyd, Inc.
,. 181 East Evans St., Suite 23, BTC-105
Jo Florence, SC 29506
[phone] (office) I [phone] (fax)
gslagleadavisfloyd.com ( www.davisfloyd.com
Guy Slagle, PE, PLS
Vice President

D
I, Davis & Floyd, Inc.
181 East Evans Street, Suite 23
D Florence, SC 29506
[phone] (office) I [phone] (fax)
gslagle(c�davisflovd.com I www.davisfloyd.com
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are not an intended recipient, please be advised that any use, dissemination, distribution, or copying of this email is strictly
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DIS
FL D
January 21, 2014
Mr. Tom Belnick
Supervisor, NPDES Complex Permitting Unit
NCDENR — DWQ
1617 Mail Service Center
Raleigh, N.C. 27699-1617
Re: Speculative Limits
City of Claremont, N.C.
McLin Creek Wastew eatment Plant
NPDES Permit No NC0081370
Dear Mr. Belnick:
The City of Claremont is considering the upgrade and - . 'on of its McLin Creek Wastewater
Treatment Plant from a permitted capacity of 0.3 MGD 1.2 MGD. In anticipation of this expansion the
City commissioned HAI, Inc. to perform a water quality mo • e Ing analysis of Lyle and McLin Creek. That
analysis has been completed and the study report submitted to NCDENR for review. Attached is a letter
of review from Ms. Pam Behm indicating agreement with the study findings. Therefore, on the behalf of
the City of Claremont it is requested that NCDENR provide updated Speculative Effluent Limits for the
McLin Creek WWTP in consideration the findings of the HAI modeling study. The discharge from the
expanded plant would be at its current location as illustrated in the HAI study report. A copy of the HAI
study report can be provided to you if required. Coordinates of the discharge point are as follows:
Latitude: 35.6956 Longitude: -81.1214
With the upgrade and expansion of the McLin Creek VVWTP the City proposes to decommission its North
WWTP (NPDES Permit No. NC0032662) and consolidate all wastewater treatment at the McLin Creek
facility.
If you have any questions, please do not hesitate to contact us.
Sincerely,
DAVIS & FLOYD, INC.
W‘-777/
Guy E. Slagle, Jr., PE
Project Director
Cc: Doug Barrick, Claremont City Manager
Engineering I Architecture ( Environmental I Laboratory
1073 13th Street NE Hickory, NC 28602 [828] 322 2290
davisfloyd.oam

Arca
NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Resources
Water Quality Programs
Pat McCrory Thomas A. Reeder John E. Skvarla, III
Govemor Director Secretary
January 15, 2014
Mr. Doug Barrick
City Manager
City of Claremont
3288 East Main Street
Claremont, NC 28610
Dear Mr. Barrick,
The DWR Modeling and Assessment Branch has reviewed the final report titled "Upper Lyle and McLin
Creek Water Quality Modeling Analysis" and modeling files provided by Hydroanalysis, Inc. We agree
with the findings detailed in the report, specifically that the Qual2k models developed indicate that
there is assimilative capacity to support expansion of the City of Claremont's and City of Conover's
facilities. The analysis was performed assuming expansions to Conover NE WWTP (Lyle Creek) of up to
twice the currently permitted flow and Claremont McLin WWTP of up to four times the currently
permitted flow and closures of Claremont North WWTP (Lyle Creek) and Conover SE WWTP (McLin
Creek).
At this point, the cities will need to determine how much expansion is actually needed and where. For
permitting questions, the best contact is Tom Belnick ([e-mail]). For SEPA questions,
the best contact is Harold Brady ([e-mail]).
If you have questions, please let us know.
Pam Behm
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Location: 512 N. Salisbury St. Raleigh, North Carolina 27604
Phone: [phone] Fax: [phone]
Internet:: www,ncwateroualitv.orq
An Equal OpportunilyWffamative Action Employer

Cy pia kiwi
NPDES Permit NC00813 70
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is
authorized to discharge through Outfall 001. Such discharges shall be limited and monitored by the Permittee
as specified below:
CHARATERISTICS
[parameter codes]
EFFLUENT LIMITS
MONITORING
REQUIREMENTS
Sample
Type
Sample
Locations
Monthly
Average
Weekly
Average
Daily
Maximum
Measurement
Frequency
[50050] Flow (MGD)
0.300
Continuous
Recording
I or E
[00310] BOD, 5day, 20°C 2 (Apr 1- Oct 31)
8.0 mg/L
12.0 mg/L
Weekly
Composite
E, I
[00310] BOD, 5day, 20°C2 (Nov 1- Mar 31)
16.0 mg/L
24.0 mg/L
Weekly
Composite
E, I
[50530] Total Suspended Solids (TSS) 2
30 mg/L
45 mg/L
Weekly
Composite
E, I
[00610] NH3 as N (Apr 1 - Oct 31)
2.0 mg/L
6 mg/L
Weekly
Composite
E
[00610] NH3 as N (Nov 1 - Mar 31)
4.0 mg/L
12 mg/L
Weekly
Composite
E
[00300] Dissolved Oxygen3
Weekly
Grab
E
[31616] Fecal Coliform (geometric mean)
200/100 ml
400/100 ml
Weekly
Grab
E
[50060] Total Residual Chlorine (TRC) 4
28 µg/L 4
Weekly
Grab
E
[00010] Temperature (°C)
Weekly
Grab
E
[00400] pH
Not < 6.0 nor > 9.0 standard units
Weekly
Grab
E
[01042] Total Copper
Monthly
Composite
E
[01092] Total Zinc
Monthly
Composite
E
[EPA 1631 E] Total Mercury6
Quarterly
Grab
E
[00625] Total Nitrogen (NO2 + NO3 + TKN)
Quarterly
Composite
E
[00665] Total Phosphorus
Quarterly
Composite
E
[TGP3B] Chronic Toxicity?
Quarterly
Composite
E
[50010] Temperature, °C
Weekly
Grab
U, D
[00300] Dissolved Oxygen
Weekly
Grab
U, D
Table Footnotes:
1. Sample Locations: E = Effluent; I = Influent; U = Upstream at NCSR 1722 (south of Claremont); D = Downstream at
NCSR 1722 (east of Claremont, see map).
2. Monthly average effluent concentrations for Biochemical Oxygen Demand (BODB) and TSS shall not exceed
15% of the respective influent values (i.e. 85% removal required).
3. Daily average dissolved oxygen effluent concentration shall not fall below 5.0 mg/L.
4. Total Residual Chlorine (TRC). The Division shall consider all effluent TRC values reported below 501.tg/L to be
in compliance with the permit. However, the Permittee shall continue to record and submit all values reported by a
North Carolina certified laboratory (including field certified), even if these values fall below 50 µg/L.
5. Chronic Toxicity (Ceriodaphnia) at 9 %; quarterly during January, April, July, October; See Special
Condition A. (2.)
6. Mercury — the Permittee shall conduct sampling and analyses according to field and laboratory techniques
described in test method EPA 1631 E, or equivalently approved low-level testing.
Units:
mg/L = milligrams per liter ml = milliliter
µg/L = micrograms per liter NH3 as N = ammonia nitrogen
BOD = biochemical oxygen demand
The Permittee shall discharge no floating solids or foam visible in other than trace amounts.

Fife kUeMovi1F 44c,L14 CvK wwTP
tsJC�O?d370
Draft Modeling Work Plan for
Upper Lyle Creek and McLin Creek
February 18„ 2013
a�
Prepared by:
Ken Hickey
481 Great Road, Suite 3
Acton, Massachusetts 01720
[phone]

Draft Modeling Work Plan for
Upper Lyle Creek and McLin Creek
Table of Contents
1.0 Introduction 2
2.0 Review of Available Studies 5
2.1 Physical Characterization 5
2.2 Hydrologic Characterization 5
2.3 Water Quality and Biological Characterization 5
2.4 Summary of Observations 7
3.0 Review of 2007 Lyle Creek Water Quality Modeling Analysis 9
3.1 Overview 9
3.2 Field Program 9
3.3 Lower Lyle Creek Model Setup and Application 11
3.4 Summary 13
4.0 Draft Modeling Analysis Work Plan 16
4.1 Conceptual Approach 16
4.2 Model Selection 16
4.3 Physical Model Domain Setup 17
4.4 Hydrologic Model Setup 17
4.5 Water Quality Model Setup 19
4.6 Application of the Water Quality Model 20
5.0 References 24
1
Hydro

1.0 Introduction
This report describes a work plan for conducting a simple water quality modeling analysis of Upper Lyle
Creek and McLin Creek. The objective of the Upper Lyle-McLin Creek modeling analysis is to support
evaluation of the potential for increased wastewater treatment plant (WWTP) wasteload allocations for
the Cities of Claremont and Conover. Specifically, the potential for increased wasteloads for Conover's
Northeast WWTP situated on Lyle Creek and Claremont's McLin Creek WWTP situated on McLin
Creek (Figure 1) will be evaluated. The modeling analysis will focus on evaluating the assimilative
capacity of the river system to receive an increased load of oxygen -demanding substances. The Upper
Lyle-McLin Creek modeling analysis will build upon and be consistent with an approved Lower Lyle
Creek modeling analysis conducted in 2007 (ENSR 2007).
The Lyle Creek watershed is situated in the Catawba River basin and drains an area of 74 square miles
(Figure 1). The Lyle Creek watershed is home to approximately 34,470 people who reside in Hickory,
Conover, Claremont, Catawba, and other municipalities (Davis & Floyd 2011). Figure 1 presents the
Lyle Creek watershed with its two largest sub -watersheds, Lyle Creek and McLin Creek. Lyle Creek
flows towards the east and drains 47.4 square miles, representing 64% of the total watershed area.
Lyle Creek is over 18 miles long (FEMA 2007) and receives flow from several tributaries. The Conover
Northeast WWTP is situated on Lyle Creek at river mile 10.3 ("river miles" or RMs are defined as
distance upstream from the mouth of a river or creek).
McLin Creek is situated south of Lyle Creek, flows toward the east-northeast and joins Lyle Creek 1.4
miles from its confluence with the Catawba River (Figure 2). McLin Creek drains an area of 27.5
square miles, representing more than one-third (36%) of the total Lyle Creek watershed area. McLin
Creek is over 10 miles long (FEMA 2007) and the McLin Creek WWTP is situated at river mile 2.5.
This draft work plan provides a summary of available physical, hydrologic, water quality, and biological
conditions in Lyle and McLin Creeks (Section 2) and an overview of the 2007 Lower Lyle Creek Water
Quality Modeling Study (Section 3). The review of available information and of the 2007 modeling
analysis are intended to provide readers with background and contextual information relevant to the
draft Upper Lyle-McLin Creek modeling work plan described in Section 4.
2
Hydro
Analysis

Lyle'Qreek Waters
474 sq. allies
Lyle and McLin Creek Watersheds
�\. Stream
/\/ Roads and Highways
WWTP
Lake, Pond or River
Municipal Boundary
McUn Creek
WWTP
Watershed (HUC 12)
1 Lyle Creek
McLin Creek
Miles
0 0.5 1
NAD83 North Carolina State Plane Feet, Data from National Hydrography Database (NHD) and NC DOT
Name' 1_Watersheds Date: 2/14/2013
Figure 1. Lyle Creek watershed with two major sub -watersheds and WWTPs indicated.
3
Hydro
Analysis

Conover NE
f WWTP Lyle Creekatershed
47.4 mlles
Claremont us-7c � r
4/010414
O
Conover
J
McLin CreekCreel;aidittied
26.5 sq. miles •16
Newton
'Maiden
McLin Creek Watershed
Tkv
McLin Creek
WWTP
/\/ Roads and Highways Ell Lake, Pond or River Watershed (HUC 12)
'�. Stream `j Municipal Boundary E Lyle Creek
L' WWTP i J McLin Creek
Catawtiaz','.•
. Ww rP�
Catawba,
Miles
0 0.5 1
NAD83 North Carolina State Plane Feet, Data from National Hydrography Database (NHD) and NC DOT Name: 2 McUnWatershed_021113 Date: 2/14/2013
Figure 2. McLin Creek Watershed with WWTPs indicated.
4
Hydro
Analysis

2.0 Review of Available Studies
A review of available studies was conducted to enhance understanding of the physical, hydrologic,
water quality, and biological characteristics of the Lyle Creek and McLin Creek study area.
2.1 Physical Characterization
Three primary sources of information were used to characterize the physical conditions in the Lyle
Creek and McLin Creek study area. Two of these sources are a FEMA Flood Insurance Study and
Geographic Information System data, described below, and the third source is the 2007 modeling
study, described in Section 3.
,2007 FEMA Flood Insurance Study (FIS) of Catawba County
A 2007 FEMA FIS was obtained and will be a useful source of physical characteristics of Lyle Creek
and McLin Creek (FEMA 2007). The FIS contains flood profiles including streambed elevations
throughout Lyle Creek and McLin Creek. These profiles will be used to obtain streambed slope and
distances to key locations, including WWTPs, highway overpasses and tributary confluences.
Geographic Information Systems (GIS)
The National Hydrography Data (NHD) set was utilized as the source of stream, river, pond and lake
locations as well as the Hydrologic Unit Code (HUC) 12 watershed delineations for Lyle Creek and
McLin Creek. The sub -watersheds within the Lyle Creek watershed were established based on the
HUC 12 delineation and the North Carolina Department of Transportation (NCDOT) May 2007 LiDAR
data and associated data products including contour intervals. Municipal boundaries, roads and
highways data were provided by NCDOT. County boundaries were provided by the North Carolina
Geodetic Survey.
2.2 Hydrologic Characterization
The FEMA Flood Insurance Study provides estimated flood elevations and associated flows associated
with flooding events (i.e., extremely high flows) in Lyle Creek and McLin Creek. The FEMA study
predicts flows that are in the upper 10% annual change of occurrence range, but does not evaluate
flows outside of this high flow range (FEMA 2007). There appears to be sparse hydrologic information
available for average or low flow conditions for the Lyle Creek and McLin Creek watersheds.
The field program associated with the 2007 modeling study captured low -flow conditions in Lyle Creek
and McLin Creek and is summarized in Section 3 below.
2.3 Water Quality and Biological Characterization
The primary source of information regarding water quality conditions in the Lyle Creek watershed is
North Carolina Department of Environment and Natural Resources (DENR) Basinwide Water Quality
Plans. These plans are published approximately every five years and provide a summary of water
quality conditions in watersheds throughout the state. Basinwide Water Quality Plans published in
1995, 1999, 2004, and 2010 were obtained and reviewed for information relative to the Lyle Creek
5
Hydro

watershed. These reports and other sources of information are briefly summarized in chronological
order below.
1995 Catawba River Basinwide Water Quality Plan
The 1995 Catawba River Basinwide Plan recommended that the Lyle Creek watershed implement a
management strategy for oxygen -consuming wasteloads from discharge facilities (NC DEM 1995), as
described below. The 1995 Plan does not report water quality measurements collected from the Lyle
Creek watershed. There was one benthic macroinvertebrate monitoring station reported in Lyle Creek.
Benthic macroinvertebrates, especially aquatic insects, are sampled to support evaluation of the
biological health and water quality conditions in stream and rivers (NC DENR 2012b). The nature and
extent of benthic macroinvertebrate communities have been found to be good indicators of water quality
in streams and are used as an efficient method of assessing aquatic health.
The Lyle Creek benthic monitoring location at the Highway 70 bridge is situated 3.5 miles upstream of
the mouth (Figure 1). Lyle Creek was assigned a biological rating of "Good" based on a 1992 benthic
macroinvertebrate survey and the fish community structure of Lyle Creek was assigned a "Good" rating
based on a 1993 survey (NC DEM 1995). McLin Creek was not included in the 1995 Basinwide Plan,
except that it was listed as a tributary of Lyle Creek.
Lyle Creek Watershed Management Strategy
The 1995 Basinwide Plan also reported on a water quality modeling study of Lyle Creek conducted by
the North Carolina Division of Environmental Management (NC DEM) in 1988 (NC DEM 1995). The
1988 modeling study was reportedly conducted to evaluate a request from the City of Conover for an
increased WWTP wasteload allocation. The 1988 modeling study is not provided in the 1995 Plan, but
reportedly included the entire Lyle Creek watershed and concluded that oxygen -consuming substances
had been "over allocated" under previous wasteload allocation procedures (NC DEM 1995). The 1988
modeling study provided the basis for the Lyle Creek Watershed Management Strategy.
Based on the 1988 watershed model findings, a Lyle Creek Watershed Management Strategy was
implemented to control oxygen -consuming wasteloads and protect the ambient (i.e., in -stream)
dissolved oxygen standard in the creek. Specifically, the watershed management strategy has been
applied to expanding WWTPs in the Lyle Creek watershed stating that NPDES discharges will receive
BOD5 and ammonia limits that hold their load of oxygen -consuming wasteloads constant (i.e., no
increase in BOD5 or ammonia loads will be approved). Effluent discharge limits on oxygen -consuming
wasteloads at proposed new facilities in the Lyle Creek watershed were also applied based on the
watershed management strategy.
1999 Catawba River Basinwide Water Quality Plan
The 1999 Catawba River Basinwide Plan recommended continuing to apply the Lyle Creek Watershed
Management Strategy. The 1999 plan does not report water quality measurements collected from the
Lyle Creek watershed. The benthic macroinvertebrate monitoring station on Lyle Creek at Highway 70
was re -surveyed in 1997 and was again assigned a "Good" rating. A benthic macroinvertebrate
monitoring station was added in McLin Creek at a location 0.2 miles upstream of the Old Catawba Road
6
Hydro
Analysis

bridge (Figure 2). The McLin Creek station was also assigned a "Good" rating based on the benthic
survey in 1997 (NC DENR 1999).
2004 Catawba River Basin wide Water Quality Plan
The 2004 Catawba River Basinwide Plan does not report water quality measurements collected from
the Lyle Creek watershed, but reports benthic macroinvertebrate survey ratings in tabular form. The
2004 plan lists the benthic ratings of Lyle Creek (monitored at the Highway 70 bridge) as having been
"Good -Fair" from each of three surveys conducted in 1992, 1997, and 2002. The 2004 plan lists the
benthic rating of McLin Creek (monitored 0.2 miles upstream of the Old Catawba Road bridge) as
having been "Good -Fair" from each of two surveys conducted in 1997 and 2002 (NC DENR 2004).
2010 Catawba River Basinwide Water Quality Plan
The 2010 Catawba River Basinwide Plan also does not provide water quality measurements, but does
provide the results of benthic and fisheries monitoring surveys. The 2010 Plan states that a McLin
Creek benthic monitoring survey conducted in 2007 resulted in a rating of "Fair." This benthic rating
triggered an impaired status for McLin Creek for not supporting aquatic life (NC DENR 2010). As a
result, McLin Creek was placed on a list of impaired waters and is described as requiring mitigation to
restore aquatic life support status. The 2010 Plan states that Lyle Creek had been assigned a "Good -
Fair" benthic rating based on a 2007 survey and had been assigned an "Excellent" fisheries rating
based on a 2004 survey.
Due to the impaired aquatic life listing, a restoration opportunities summary was provided for McLin
Creek as part of the 2010 Plan. The plan describes lower reaches of McLin Creek as being adjacent to
agricultural properties and opines that the "Fair" benthic rating, based on the 2007 survey, was likely
due to adverse impacts of agricultural and industrial stormwater runoff. The plan also states that;
"Stormwater runoff may have had more of an impact due to drought causing the runoff to be more
concentrated. The biological community is expected to improve as normal rainfall levels return." (NC
DENR 2010). The 2010 Basinwide Plan does not mention the McLin Creek WWTP as a potential cause
of aquatic life impairment in the creek.
2.4 Summary of Observations
The review of available Lyle Creek and McLin Creek -related studies and information (excluding the
2007 Lower Lyle Creek study described in Section 3) yields the following observations:
1. There is a paucity of hydrologic information available, with the exception of high -flow (i.e., flood)
event conditions.
2. There is also very little water quality information available.
3. NC DENR Basinwide Water Quality Plans developed over the past 20 years do not appear to
have included water quality measurements, but do provide biological survey results;
4. Based on a 1988 water -quality model, the Lyle Creek watershed was determined to be over -
allocated for oxygen -consuming wasteloads (NC DENR 1995);
7
Hydro
Analysis

5. Based on the 1988 water -quality model, a Lyle Creek Watershed Restoration Strategy was
implemented to hold wasteloads in the watershed constant (NC DENR 1995);
6. Over the past 20 years, Lyle Creek biological surveys have consistently resulted in ratings of
acceptable biological status.
7. In 2010, McLin Creek was listed as impaired for failure to support aquatic life, based on a 2007
benthic macroinvertebrate survey (NC DENR 2010). The DNER 2010 report opined that a
drought, combined with stormwater runoff from industrial and agricultural areas were the causes
of the non -supporting benthic rating obtained in 2007.
The review of available studies enhanced our understanding of the Lyle Creek watershed.
8
Hydro

3.0 Review of 2007 Lyle Creek Water Quality Modeling Analysis
3.1 Overview
In 2007, a wasteload allocation (WLA) study was conducted on Lyle Creek in support of the City of
Hickory's plan to expand the Catawba WWTP to a discharge flow of 3.0 MGD from 0.225 MGD. The
City of Hickory is located at the headwaters of Lyle Creek in the northwestern end of the basin and the
Catawba WWTP is situated near the mouth of Lyle Creek (Figure 1). The 2007 study featured a field
program and water quality modeling analysis. The study was designed and conducted to provide a
scientific basis for increasing the Catawba WWTP's wasteload allocation (ENSR 2007).
The 2007 Lyle Creek study area is shown in Figure 3, with green lines across the creeks indicating
upstream boundaries and a red line across Lyle Creek indicating the downstream boundary. The
Catawba WWTP discharges to Lyle Creek at a location 0.6 miles from the confluence with the Catawba
River. The study area was bounded upstream at the Highway 70 bridge (at RM 3.5) and downstream at
the mouth of Lyle Creek (RM 0.0), spanning a total of 3.5 miles. McLin Creek is included as a tributary
boundary, entering Lyle Creek at RM 1.5.
The study focused on determining the Toad of the oxygen -consuming substances BOD5 and ammonia
from the Catawba WWTP that Lyle Creek could assimilate while still maintaining ambient dissolved
oxygen concentrations (DO) above the minimum water quality standard of 5.0 mg/L. A field data
collection program was conducted under drought conditions in July and August 2007. The field
program featured six water quality sampling events, several river flow measurements, water level
measurements, and a time of travel study (featuring release and tracking of dye in the river). The
modeling analysis was conducted using the hydrodynamic model, DYNHYD, and the water quality
model, WASP.
A partial description of the 2007 field program and water quality modeling analysis is provided below.
The reader is referred to the modeling report for a full summary of the 2007 Lower Lyle Creek modeling
analysis (ENSR 2007). This review is focused on the overall approach of the 2007 modeling analysis
and specification of model upstream and tributary boundaries.
3.2 Field Program
The field program conducted in support of the Lower Lyle Creek modeling analysis resulted in several
findings including:
1. The field program captured severe drought conditions in July and August 2007 resulting in
worst -case conditions in terms of low flow, heat, and lack of rainfall. Specifically, the 7Q10 for
Lyle Creek is 16 cfs and is higher than any streamflow measurements collected during the
summer of 2007 field program (ENSR 2007). Thus, the 2007 field program captured low flow
conditions that were lower than the 7Q10 in the study area.
2. Streamflow and water quality measurements were collected in Lyle Creek and McLin Creek.
This may be obvious, but it is important because the measurements obtained from these creeks
during the summer of 2007 are the only measurements found in available reports. Streamflow,
9
Hydro

DO, BOD5, ammonia, and other parameter concentrations were measured at up to 10 locations
during up to 6 sampling events in July and August 2007.
3. The flow of water near the mouth of Lyle Creek was observed to reverse direction intermittently
due to dam operations in the Catawba River system. A time of travel study (i.e., dye study)
found that the water flowed efficiently out of Lyle Creek (i.e., residence time of water in this area
was short) and was not significantly delayed by intermittent flow reversals.
The 2007 field program captured hydrologic and water quality conditions during a low -flow summertime
period. Field measurements collected at the upstream Lyle Creek and McLin Creek tributary model
boundaries are summarized below.
Upper Lvle Creek Field Measurements
The upstream boundary of the 2007 model was the Highway 70 bridge over Lyle Creek. Table 1
provides measurements collected at the Highway 70 bridge during the summer of 2007. Key flow and
water quality measurement values ranged as follows:
• Streamflow: 1.9 to 9.0 cfs
• BOD5 Concentrations: 2.0 to 9.4 mg/L
• Ammonia Concentrations: 0.036 to 0.056 mg/L
• DO Concentrations: 7.7 to 9.7 mg/L
These field measurements provided the basis for establishing model boundary conditions.
Table 1. Field measurements collected at the Lyle Creek upstream boundary
Sampling
Streamflow
cBOD5
BOD5
BOD30 b Ammonia
D.O.
Tem erature
Date
(cfs)
(mg/L)
(mg/L)
(mg/L) (mg/L)
(mg1L)
(deg C)
July 5, 2007
9.00
R
R
- 0.056
9.72
23.24
July 10, 2007
July 31, 2007
8.26
5.74
4.1 U
9.4
4.1 U
2 U
11 0.052
- 0.036 J
9.71
7.74
24.37
23.04
August 1, 2007
3.94
NA
NA
NA NA
NA
NA
August 15, 2007
1.92
4.4
4.2 U
- 0.04 J
8.68
25.6
August 20, 2007
3.52
NA
NA
NA f NA
8.32
25.6
Notes:
Source: ENSR 2007
_
"R" = QC indicates that the data are unusable
"U" = Below reporting limit
"J" = Estimated value between reporting limit and minumum detection limit
"NA" = Not analyzed i
10
Hydro

McLin Creek Field Measurements
A tributary boundary of the 2007 model was located at the confluence of McLin Creek with Lyle Creek.
Field measurements were collected at the Old Catawba Road bridge over McLin Creek and applied as
the McLin tributary boundary conditions in the model. Table 2 provides measurements collected at the
Old Catawba Road bridge during July and August 2007. Key flow and water quality measurements
values ranged as follows:
• Streamflow: 1.2 to 9.7 cfs
• BOD5 Concentrations: 2.0 to 12 mg/L
• Ammonia Concentrations: 0.036 to 0.11 mg/L
• DO Concentrations: 7.2 to 9.4 mg/L
These field measurements provided the basis for establishing model boundary conditions, as described
below.
Table 2. Field measurements collected at the McLin Creek tributary boundary
Sampling
Streamflow
cBOD5
(mg/L)
BOD5
(mg1L)
BOD30
(mg1L)
L Ammonia D.O. ;Temperature
I (mg1L) (mglL) j (deg C)
Date
(cfs)
July 5, 2007
5.05
R
R
-
0.06 9.38 22.07
July 10, 2007
5.54
4.1 U
12
9.6
0.06 9.33 23.47
July 31, 2007
9.73
2
2 U
-
0.036 J k 7.73 E 21.88
Au_gust 1, 2007
5.40
NA
NA
NA
NA NA NA
August 15, 2007
9.21
3
2 U
-
0.11 J 7.9
25.46
August 20, 2007
1
= E NA
NA
NA
NA 7.15
24.55
Notes:
Source: ENSR 2007
L
!
"R" = QC indicates that the data are unusable
"U" = Below reporting limit
"J" = Estimated value between re
"NA" = Not analyzed
orting limit and
limit
minumum detection
_
3.3 Lower Lyle Creek Model Setup and Application
The 2007 modeling analysis was focused on determining the load of the oxygen -consuming
substances, BOD5 and ammonia, from the Catawba WWTP that Lyle Creek could assimilate while still
maintaining ambient dissolved oxygen concentrations (DO) above the minimum water quality standard
of 5.0 mg/L. The modeling evaluation was conducted using the hydrodynamic model, DYNHYD, and
the water quality model, WASP. These are widely -used, public domain models that were appropriate
tools to support the WLA study.
11
Hydro

The Lyle Creek water quality model was setup and calibrated using field measurements collected
during the summer of 2007 and other available information. The model was then applied to simulate a
set of "what if" scenarios using different increased Catawba WWTP effluent discharge conditions during
the summer low -flow period. The model was applied to predict ambient water quality conditions,
primarily focusing on ambient DO in Lyle Creek. The model predicted ambient water quality conditions
associated with each Catawba WWTP effluent discharge scenario. Using this approach, the 2007
modeling analysis sought to identify the largest WLA that the Catawba WWTP could receive without
resulting in a violation of the minimum DO standard of 5.0 mg/L in Lyle Creek.
The modeling report concluded that "Scenario #3" featuring Catawba WWTP flow of 3.0 MGD, BOD5 of
5 mg/L, ammonia of 2 mg/L and effluent DO of 6.0 mg/L was predicted to result in no exceedances of
the ambient DO standard of 5.0 mg/L (ENSR 2007). This scenario represented a significantly
increased wasteload allocation compared to the Catawba WWTP's previous NPDES permit conditions
of 0.225 MGD and a BOD5 of 30 mg/L.
Model upstream and tributary boundaries in the Lower Lyle Creek model are summarized below.
Upstream and tributary model boundaries are important because they represent constraints relative to
the Upper Lyle Creek and McLin Creek water quality modeling analyses described in Section 4 below.
Upstream and Tributary Boundary Conditions
The 2007 model specified the upstream Lyle Creek and McLin Creek tributary modeling boundaries
based on measurements collected during the summer 2007 field program. Streamflows were specified
using regression equations that included measured streamflows and precipitation records for the period
of July 31 through August 20 (ENSR 2007). Figure 4 provides daily average streamflows applied to the
model at the upstream Lyle Creek boundary (top) and tributary McLin Creek boundary (bottom).
Streamflows from Upper Lyle Creek ranged from 3.2 to 5.2 cfs and flows from the McLin Creek tributary
ranged from 5.4 to 5.6 (with the exception of higher flows on August 4th)
Daily water quality boundary conditions were established by interpolating between field measurements
event values during the summer 2007 field program (Tables 1 and 2). In addition, ultimate BOD
estimates were calculated, using the ratio of BOD5 to BOD30, known as an f-factor, and were applied to
the model. BOD30 laboratory analyses were performed on only one set of water quality samples
(collected on July 10, 2007). Based on review of the 2007 report, it is not entirely clear how the f-factor
was calculated and applied during the modeled time period of July 31 to August 20, 2007.
Through a combination of field data interpolation and ultimate BOD calculations, the following ranges of
water quality boundary conditions were applied to represent the upstream Lyle Creek boundary
conditions (ENSR 2007).
Upstream Lyle Creek Boundary Conditions
• Streamflow: 3.2 to 5.2 cfs
• Ultimate cBOD Concentrations: 10.8 to 24.7 mg/L
• Ammonia Concentrations: 0.036 to 0.056 mg/L
• DO Concentrations: 7.7 to 9.7 mg/L
12
Hydro

The 2007 report states that BOD5 measurements ranging from 2 to 4.2 mg/L and a BOD30
measurement of 11 mg/L were used to obtain ultimate cBOD concentrations ranging from 10.8 to 24.7
mg/L. It is not clear how the ultimate cBOD estimates were obtained.
McLin Creek Model Boundary Conditions
McLin Creek tributary boundary conditions were apparently established following the same
methodology as described for the Lyle Creek upstream boundary above. The specific values used are
not provided in the modeling report. The ranges of McLin Creek tributary boundary conditions can be
readily obtained from the daily streamflow figure (Figure 4) and water quality field measurements (Table
2), with the exception of the ultimate BOD values, as follows:
• Streamflow: 5.4 to 5.6 cfs
• Ammonia Concentrations: 0.036 to 0.11 mg/L
• DO Concentrations: 7.2 to 9.4 mg/L
3.4 Summary
In summary, the 2007 modeling analysis simulated flow and water quality conditions in the Lower Lyle
Creek study area during low -flow, summertime conditions. Under the successful "Scenario #3",
ambient DO in Lower Lyle Creek was predicted to be very close to, but not below, the water quality
standard of 5.0 mg/L. As a result, there does not appear to be significant assimilative capacity for
additional loading of oxygen -demanding substances available in the Lower Lyle Creek study area.
Streamflow and water quality measurements and modeled boundary conditions at the Lyle Creek
upstream boundary and the McLin Creek tributary boundary were evaluated and provide useful data
and information.
13
Hydro

/ uS:TO
Claremont f ��
2007 Water Quality Study Area
Upstream Boundaries of
2007 Model
\Downstream Boundary of
2007 Model
'\. Stream
/\/ Roads and Highways
Lake, Pond or River
WWTP
Municipal Boundary
Watershed (HUC 12)
Lyle Creek
McLin Creek
Miles
0 0.25 0.5
NADt33 North Carolina State Plane Feet. Data from National Hydrography Database (NHD) and NC DOT Name: 3_2007StudyArea 02123013 Date: 2/14/2013
Figure 3. 2007 Lower Lyle Creek Modeling Study Domain
14
Hydro
Analysis

Figure 3-2 Calculated daily average flow rate at Lyle Creek upstream model boundary Station t.C1a
Figure 34. Calculated deity average lbw rate at AActin Creek tributary model boundary Station MCI
4100
5.00
4,00
aoo.
ion
1.:1111111iB
1111
htf://:944"/":44P:fiti
:////11/
Figure 4. Daily Average Flows at the Upstream Lyle Creek (top) and McLin Creek tributary
(bottom) Applied in the Lower Lyle Creek Model (excerpted from ENSR 2007).
15
Hydro
Analysis

4.0 Draft Modeling Analysis Work Plan
The proposed simple water quality modeling analysis of Upper Lyle Creek and McLin Creek will focus
on determining the assimilative capacity of the creeks to receive additional WWTP wasteloads. The
modeling analysis will simulate oxygen -consuming substances, BOD and ammonia, and their effect on
ambient (i.e., in -stream) dissolved oxygen (DO) concentrations in McLin Creek and Lyle Creek. The
modeling analysis will predict whether specific loadings of oxygen -consuming substances to the stream
will result in the reduction of ambient DO concentrations to levels below the water quality standard of 5
mg/L in Lyle Creek or McLin Creek.
The objective of the Upper Lyle-McLin Creek modeling analysis is to provide sufficient information to
support determination of the acceptability of increasing the WLA to these creeks. Our conceptual
approach for conducting a modeling analysis to achieve this objective and a description of the model
setup and application process are provided below.
4.1 Conceptual Approach
The Upper Lyle-McLin Creek modeling analysis will be consistent with and built -upon the 2007
modeling analysis. The analysis will simulate steady-state, summetime low -flow conditions, based the
2007 conditions. Use of a steady-state model is appropriate for Upper Lyle Creek and McLin Creek
because, under low -flow conditions, flows and wasteloads are relatively constant. Also, the steady-
state model may be applied to simulate various scenarios (e.g., with different flows and wasteloads) to
support evaluation of assimilative capacity under different conditions.
The Upper Lyle-McLin Creek model's physical configuration will Zink with the 2007 Lower Lyle Creek
model such that the upstream boundaries of the 2007 Lower Lyle Creek model will serve as Upper
Lyle-McLin model downstream compliance points. The Upper Lyle-McLin Creek model will simulate the
combined flow and water quality characteristics of the ambient river and the VVWTPs discharges and
will support comparison of water quality conditions to those obtained in the 2007 model.
The modeling analysis will be subject to the following two constraints:
1. The concentrations of oxygen -demanding substances (BOD and ammonia) entering the Lower
Lyle Creek reach must be less than or equal to the concentrations used in the 2007 model
simulations; and
2. The ambient dissolved oxygen concentration in the model study area must be above the water
quality standard of 5.0 mg/L at all times and locations.
These constraints were selected to ensure that the conditions simulated in the Upper Lyle-McLin Creek
2013 model are consistent with 2007 drought conditions and comply with the water quality standard.
4.2 Model Selection
The QUAL2K model has been tentatively selected for the Upper Lyle-McLin Creek modeling analysis
because it is a straightforward, widely -used, public -domain modeling tool. QUAL2K is a water quality
model for streams and rivers that is available and supported by the United Stated Environmental
16
Hydro

Protection Agency (USEPA) Region 4. The model incorporates many components of water quality
including BOD and ammonia effects on ambient dissolved oxygen concentrations, as described in the
QUAL2K User's Manual (Chapra 2008). The model requires a number of inputs in order to evaluate
water quality as a function of centerline distance. The model is one-dimensional and does not
incorporate lateral conditions that may impact flow, current speed, or water quality.
QUAL2K simulates hydrology and water quality in streams and contains all of the characteristics
required to support Upper Lyle-McLin Creek modeling objectives. Equally importantly, NC DENR staff
are familiar with QUAL2K and the model has a relatively easy -to -use interface. These features will
facilitate a transparent modeling and model review process. For these reasons, QUAL2K is a good
choice to support the Upper Lyle-McLin Creek modeling analysis.
4.3 Physical Model Domain Setup
Physical characteristics required to setup the model include stream width, slope, centerline distances
(i.e. reach length), and Manning's roughness (n). River slope and centerline distances will be obtained
from a recent FEMA Flood Insurance study that includes flood profile sheets with stream distance and
streambed elevations throughout the study area (FEMA 2007). Stream widths will be estimated based
on site reconnaissance visits and Manning's n will be initially estimated based on site information (e.g.,
stream substrate) and literature values.
Upper Lyle Creek is defined as the portion of Lyle Creek above the Highway 70 bridge, drains a total of
43.6 square miles, and has several large sub -watersheds and tributaries. As shown in Figure 5 and
compiled in Table 3, these sub -watersheds were delineated and their drainage areas calculated. A
headwaters watershed of 19.9 square miles (46% of the Upper Lyle Creek sub -watershed) drains to a
location just above the Conover Northeast WWTP. Bakers Creek, Mull Creek and several other
tributaries drain to Upper Lyle Creek as it flows toward the Catawba. These tributaries will be included
in the physical specification of Upper Lyle Creek in the model. A conceptual diagram of the physical
configuration of the Upper Lyle Creek model domain is provided in Figure 6. This model domain will
include several tributary sources and the Conover Northeast WWTP discharge.
The conceptual diagram of the physical configuration of the McLin Creek model domain is provided in
Figure 7. This model domain is relatively simple because the downstream distance is shorter and there
are no large tributaries along the reach of the creek included in this analysis. The City of Claremont's
McLin Creek WWTP is situated 2.5 miles upstream of the confluence with Lyle Creek.
4.4 Hydrologic Model Setup
The hydrologic model will be setup using the low -flow conditions established in the 2007 model. For
Upper Lyle Creek, the total flow at Highway 70 will be distributed proportionately to upstream tributaries
based on watershed drainage area (as shown in Figure 5). The sub -watershed area and percent of
total drainage area used to estimate proportional flow is provided in Table 3. For model input, a
simplified tributary boundary condition scheme will likely be adapted. For example, the Trib. 1 and Mull
Creek sub -watersheds may be combined and represented as a single tributary source in the model.
17

Table 3. Upper Lyle Creek Watershed Areas and Flow Proportions
Sub -watershed & Tributary
Rivermile of
Sub -watershed
% of Upper Lyle
above Highway 70 bridge
Confluence
area (sq miles)
Creek Area & Flow
Headwaters
10.3
19.9
46%
Bakers Creek
9.7
6.8
16%
Unnamed Trib
7.1
2.7
6%
Central Watershed
NA
4.1
5.0
' 9%
Mull Creek
5.5
11%
Trib 1
5.4
1.3
3%
Lower Watershed
NA
3.8
9%
For McLin Creek, the total flow at the Old Catawba bridge was assumed to be the same as the flow
above the McLin Creek WWTP (except for the WWTP flow itself). This simplifying assumption appears
to be appropriate because of the relatively short distance and small watershed area associated with the
McLin Creek reach.
Actual flows from the Conover Northeast WWTP and McLin Creek WWTP for August 2007 were
obtained from discharge monitoring reports (DMRs) and are presented in Tables 4 and 5, along with
NPDES-permitted conditions. As shown in Table 4, the Conover Northeast WWTP was operating at
approximately one-third of permitted flow and one -tenth of permitted BOD5 concentration during the
August 2007 period. During August 2007, the McLin Creek WWTP was operating at approximately
60% of permitted flow and 90% of permitted BOD5 concentration (Table 5).
Table 4. Conover Northeast WWTP Effluent Characteristics
Conover Northeast WWTP
Parameters
Actual Aug. 2007
Existin
Effluent
NPDES Permit
Characteristics 1
Conditions
(monthly ave.)
(monthly ave.)
Flow
0.559 MGD
1.5 MGD
BOD5 concentration (summer)
0.7 mg/L
8.0 mg/L
NH3 as N concentration (summer)
0.56 mg/L
2.0 mg/L
Dissolved Oxygen concentration
7.23 mg/L
5.0 mg/L
' Source: City of Conover 2007
18
Hydro

Table 5. McLin WWTP Effluent Characteristics
McLin Creek WWTP Parameters
Actual Aug. 2007
Existing
Effluent
NPDES Permit
Characteristics 1
Conditions
(monthly ave.)
0.174 MGD
(monthly ave.)
0.3 MGD
Flow
BOD5 concentration (summer)
7.1 mg/L
8.0 mg/L
NH3 as N concentration (summer)
0.9 mg/L
2.0 mg/L
Dissolved Oxygen concentration
7.12 mg/L
5.0 mg/L
Source: Woodard & Curran 2007
4.5 Water Quality Model Setup
Water quality model set up will feature specification of a suite of water quality parameter values at
upstream boundaries, tributary boundaries, and at the WWTP effluent discharge locations. Locations
of water quality boundary conditions in Lyle and McLin Creek are shown in schematic Figures 6 and 7.
Water quality parameters specified will include:
• Temperature
• Dissolved oxygen concentration
• cBOD concentration
• Ammonia concentration
Upstream (situated above the Conover Northeast WWTP in Lyle Creek and above the McLin Creek
WWTP in McLin Creek) and tributary water quality conditions will be estimated based on available data.
Actual WWTP discharge water quality conditions from August 2007 time period are provided in Tables
4 and 5 and will be applied to setup the water quality model.
Selection of appropriate water quality rate coefficients is a critical step in the model setup process.
Coefficients specifying the rates of several key biological and chemical processes will be selected
based on available guidance and literature (e.g., Bowie et al. 1985). These rate coefficients are
important because they specify the rates at which reactions controlling the consumption and generation
of ambient dissolved oxygen occur. A number of natural processes that occur in a water body have an
effect on the availability of DO in the water body. These rates include carbonaceous and nitrogenous
oxygen consumption and surface re -aeration rate. Values for these rates will be carefully selected and
documented as part of the modeling process.
19
Hydro

4.6 Application of the Water Quality Model
The QUAL2K model of Upper Lyle Creek and McLin Creek will be a simple model designed to assess
the potential effects of small WWTP wasteloads on ambient water quality. The model will be set up and
run using available physical, hydrologic and water quality data and parameter values as described
above.
Upper Lyle-McLin Creek Model will be applied to simulate two types of scenarios:
1. August 2007 conditions, with creek hydrologic and water quality conditions associated with the
2007 summertime drought period. This type of scenario will be simulated using (a) actual
August 2007 WWTP characteristics and (b) NPDES permitted WWTP characteristics, as
presented in Tables 4 and 5. These modeling analyses will support evaluation of whether the
existing NPDES-permitted WLAs are acceptable in terms of ambient water quality in Lyle Creek
and McLin Creek.
2. Auqust 2007 conditions; with various increased wasteload conditions, This type of scenario will
support evaluation of assimilative capacity of the river system to receive increased WLA.
Increased wasteloads will be specified for the Conover Northeast WWTP and/or the McLin
Creek WWTP and the model will be applied to predict the ambient water quality conditions
resulting from these increased wasteloads.
We will coordinate closely with NC DENR modeling staff in setting up and applying the Upper Lyle
Creek and McLin Creek models.
20
Hydro
Analysis

Headw'ters Watershed
t a 19.9 q. mil
Lyle and McLin Creek Watersheds
Stream
Bakers Creek Watershed
•6:8\q. mites
Unnamed) rib.
Watershed
2.7 sq; miles
1
Watershed
1.3�qlmiles
Centra Watershed
SSr
4.1 sq. miles, J,
Conover J _^
NE WWTP
-`-1.ao er Water•'
3.8 sq. miles
ull Cr 1t Watersh d�
1 Ssq.'1nilW
Lake. Pond or River
/\/ Roads and Highways n Lyle Creek Watershed draining to U.S. 70
A
Miles
0 0.5 1
NADa3 North Groins Stale Plane Feet, Data from National Hydrography Database INFO) Name: 5_VatitershedsDetin
Figure 5. Lyle Creek Watershed with sub -watershed delineations
21
Hydro
Date: 2/14,2013
Analysis

Upper Lvle Creek Headwaters:
Q, T, DO, BOD, NH3
77
Conover Northeast
WWTP Outfall
Q, T, DO, BOD, NH3
G_
Tributary Inflows 77�
Representing Bakers Creek,
Mull Creek, and other
tributaries
Q, T, DO, BOD, NH3
10
40
Figure 6. Conceptual Schematic of Upper Lyle Creek Model Domain
22
Hydro

McLin Creek:
Q, T, DO, BOD, NH3
McLin Creek �� WWTP O utfa II �{O� �c)
Q, T, DO, BOD, NH3 C°,>
Figure 7. Conceptual Schematic of McLin Creek Model Domain
23
Hydro
Analysis

5.0 References
Chapra, S.C., Pelletier, G.J. and Tao, H. 2008. QUAL2K: A Modeling Framework for Simulating River
and Stream Water Quality, Version 2.11: Documentation and User's Manual. Civil and Environmental
Engineering Dept., Tufts University, Medford, MA.
City of Conover 2007. Effluent Discharge Log for City of Conover NEWWTP, NPDES Permit No.
NC00024252, August 2007.
Davis & Floyd 2011. Preliminary Engineering Report for Catawba County, N.C., McLin/Lyle Creek —
Basin Study, Catawba County, Newton, NC, Davis & Floyd Job No. 041016.00, December 2011.
Bowie, G.L. , Mills, W.B., Porcella, D.B., Campbell, C.L., Pagenkopf, J.R., Rupp, G.L., Johnson, K.M.,
Chan, P. W.H. 1985, Gherini, S.A. Rates, Constants, and Kinetics Formulations in Surface Water
Modeling (Second Edition). Tetra Tech, Inc. for the Environmental Research Laboratory, Office of
Research and Development, U.S. Environmental Protection Agency, Athens, GA. EPA/600/3-85/040.
ENSR 2007. Wasteload Allocation Study for the Hickory Catawba WWTP, Catawba, North Carolina.
Prepared for HSMM, Spartanburg, South Carolina; Prepared by ENSR Corporation, Document No.
12401-001. December 2007.
FEMA 2007. Flood Insurance Study. A Report of Flood Hazard in Catawba County, North Carolina.
Federal Emergency Management Agency, State of North Carolina, Flood Insurance Study Number
37035CV001A. September 5, 2007.
NC DEM 1995. Catawba River Basinwide Water Quality Management Plan. Prepared by: North
Carolina Division of Environmental Management, Water Quality Section, Raliegh, NC. July 1995
NC DENR 1999. Catawba River Basinwide Water Quality Plan. North Carolina Department of
Environment and Natural Resources, Division of Water Quality, Water Quality Section. December 1999.
NC DENR 2004. Catawba River Basinwide Water Quality Plan. Prepared by: Dave Toms, NC
Department of Environment and Natural Resources, Division of Water Quality - Planning, September
2004.
NC DENR 2010. Catawba River Basinwide Water Quality Plan. North Carolina Department of
Environment and Natural Resources, Division of Water Quality, Basinwide Planning Unit, September
2010.
NC DENR 2012. Standard Operating Procedures for Benthic Macroinvertebrates. Biological
Assessment Unit, North Carolina Department of Environment and Natural Resources, Division of Water
Quality, Environmental Sciences Section. October 1, 2012.
Woodard & Curran 2007. City of Claremont, North Carolina, Monthly Operating Report, August 2007.
24
Hydro

/Y
Belnick, Tom
From: Behm, Pamela
Sent: Friday, February 22, 2013 3:56 PM
To: Belnick, Tom; Berry, Ron; Stecker, Kathy
Subject: FW: Draft Upper Lyle-McLin Creek modeling work plan
Attachments: Draft Upper Lyle-McLin Modeling Work Plan Feb 18 2013.pdf
***************************************************************
Pam Behm
NC DWQ Modeling and TMDL Unit
1617 Mail Service Center
Raleigh, NC 27699
Email: [e-mail]
Phone: [phone]
Fax: [phone]
E-mail correspondence to and from this address may be subject to the North Carolina Public Records Law and may be disclosed to third parties.
From: Ken Hickey[mailto:khickeyCa�hydroanalysisinc.com]
Sent: Thursday, February 21, 2013 12:01 PM
To: Behm, Pamela
Cc: Gene Haynes; Guy Slagle
Subject: Draft Upper Lyle-McLin Creek modeling work plan
Pam,
Please find attached a draft modeling work plan for Upper Lyle and McLin Creek, as previously discussed.
Please distribute this document to your team prior to our meeting on Tuesday. I look forward to talking with
you about this project.
By the way, do you have a projector setup that I could use during our meeting? I would like to present some
Powerpoint slides to facilitate the discussion.
Thank you,
Ken Hickey
HydroAnalysis, Inc.
978-501-5111 (mobile)
978-263-1092 (office)
1

CO/C/aAmn,%J -r Z/1//3 ;OM
Belnick, Tom
• Subject:
Location:
Mfg with Cities of Claremont and Conover
9th Floor Conference Room
Start: Tue 2/26/2013 1:30 PM
End: Tue 2/26/2013 3:00 PM
Show Time As: Tentative
Recurrence: (none)
Meeting Status: Not yet responded
Organizer: Behm, Pamela
Required Attendees: Belnick, Tom; Berry, Ron; Stecker, Kathy
Aw lake Notisf
CGovvIt.4, Rt.
Meeting with Cities of Claremont and Conover to discuss the draft Mclin/Lyle Creek modeling work plan, potential
expansion options.
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McLin Creek Watershed
McLri Creek WWTP Lake. Pond or Reservoir A August 20t2 Obsorvabon Points
/\/ Roads and Highways Municipal Boundary
Stream or RNer n Watershed (HUC 12)
IMMO Mies
0 0.5 t
NA063 North Carolna Stab Rand Feet Data ham Nabotil Hydrogapay Oatatane (NND1 and NC DOT Name 2_111cL,nWatarahed Dais tOr4r2O12
Figure 2. Map of McLin Creek Watershed
5
Hydro
Analysis

Lyle and McLin Creek Watersheds
'Th•—• Stream or River
Lake, Pond or Reservoir
Watershed (HUC 12)
Ell
Municipal Boundary
County Boundary
/\/ Major Highway
NAD83 North Carolina State Plane Feet, Data from National Hydrography Database (NHD) and NC DOT
0 0.5 1
Name: Watersheds Date:
A
M'

ATA
NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins Dee Freeman
Governor Director Secretary
May 4, 2011
Mr. Doug Barrick
City Manager
City of Claremont
P. O. Box 446
Claremont, NC 28610
f�tareK-4 LK /Vovwfa•i
Pvire
tiv ki- n 1 ) u)n /
Subject: Speculative Effluent Limits
Claremont WWTPs
Permits NC0032662 and NC0081370
Catawba County
Catawba River Basin
Dear Mr. Barrick:
This letter provides speculative effluent limits for 0.25 MGD at the Claremont North WWTP, which is
currently permitted at 0.10 MGD, and for 0.60 MGD and 0.85 MGD at the Claremont McLin Creek WWTP,
which is currently permitted at 0.30 MGD. The Division received the speculative limits request in a letter
dated March 2, 2011 from William S. Clayton of Davis & Floyd, Inc. Please recognize that speculative limits
may change based on future water quality initiatives, and it is highly recommended that the applicant verify
the speculative limits with the Division's NPDES Unit prior to any engineering design work.
Receiving Streams. Mull Creek, the receiving stream for Claremont North WWTP, and McLin Creek,
the receiving stream for Claremont McLin Creek WWTP, both flow into Lyle Creek and are part of the
Lyle Creek watershed within the Catawba River Basin. Lyle Creek discharges into Lake Norman. Mull
Creek and McLin Creek have stream classifications of WS-IV and WS-IV CA, respectively. Waters with
the WS-IV classification have a best usage as a water supply for drinking, culinary, or food -processing
purposes and for aquatic life propagation and maintenance of biological integrity, wildlife, secondary
recreation and agriculture. The CA classification applies additional Nonpoint Source and Stormwater
Pollution Control Criteria. Mull Creek has a summer 7Q10 flow of 1 cfs, a winter 7Q10 flow of 1.6 cfs,
and an annual average flow of 5 cfs. McLin Creek has a summer 7Q10 flow of 5 cfs, a winter 7Q10 flow
of 9 cfs, and an annual average flow of 26 cfs.
Speculative Effluent Limits. Based on Division review of receiving stream conditions, the Lyle Creek
Watershed Management Strategy, and other water quality modeling results, speculative limits were
developed. The proposed expansion to 0.25 MGD at Claremont North WWTP is presented in Table 1.
Page 1 of 3
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Location: 512 N. Salisbury St. Raleigh, North Carolina 27604
Phone: [phone] FAX: [phone] Customer Service: 1-877-623-6748
Internet: www.ncwaternualitv.org
NoIle Carolina
�tura!ly

The proposed expansions to 0.60 MGD and 0.85 MGD at Claremont McLin Creek WWTP are presented
in Tables 2 and Tables 3, respectively. A complete evaluation of these limits and monitoring
requirements for metals and other toxicants, as well as potential instream monitoring requirements,
will be addressed upon receipt of a formal NPDES permit application.
A feature of the speculative limit development include the following:
• BOD/NH3/DO Limits. The Lyle Creek Management Strategy was developed to establish BOD,
NH3, and DO limits for new or expanding dischargers in the Lyle Creek watershed so the dissolved
oxygen water quality standard would be met in Lyle Creek prior to discharge into Lake Norman. In
the case of the Claremont McLin Creek WWTP, the strategy limits had already been applied so any
future expansion will be based on freezing current permitted BOD and ammonia loads (i.e., facility
will not be allowed to discharge oxygen -consuming waste above what is currently permitted). The
resultant limits at expanded flows of 0.25 MGD (Table 1) and 0.60 MGD (Table 2) are considered
technologically -feasible.
TABLE 1: Speculative Limits for Claremont North WWTP (Proposed Expansion to 0.25 MGD)
Effluent Characteristic
Effluent Limitations
Monthly Average
Weekly Average
Daily Maximum
Flow
0.25 MGD
BOD5 summer
8.0 mg/L
12.0 mg/L
BOD5 winter
16.0 mg/L
24.0 mg/L
NH3 as N summer
2.0 mg/L
6.0 mg/L
NH3 as N summer
4.0 mg/L
12.0 mg/L
Dissolved Oxygen
Not less than 5.0 mg/L, daily average
TSS
30 mg/L
45 mg/L
TRC
28 ug/L
Fecal coliform (geometric mean)
200/100 ml
400/100 ml
Chronic Toxicity Pass/Fail
(Quarterly test)
28%
TABLE 2: Speculative Limits for Claremont McLin Creek WWII' (Proposed Expansion to 0.60 MGD)
Effluent Characteristic
Effluent Limitations
Monthly Average
Weekly Average
Daily Maximum
Flow
0.60 MGD
BOD5 summer
4.0 mg/L
6.0 mg/L
BOD5 winter
8.0 mg/L
12.0 mg/L
NH3 as N summer
1.0 mg/L
3.0 mg/L
NH3 as N winter
2.0 mg/L
6.0 mg/L
Dissolved Oxygen
Not less than 5.0 mg/L, daily average
TSS
30 mg/L
45 mg/L
TRC
28 ug/L
Fecal coliform (geometric mean)
200/100 ml
400/100 ml
Chronic Toxicity Pass/Fail
(Quarterly test)
16%
Page 2 of 3

TABLE 3: Speculative Limits for Claremont McLin Creek WWTP (Proposed Expansion to 0.85 MGD)
Effluent Characteristic
Effluent Limitations
Monthly Average
Weekly Average
Daily Maximum
Flow
0.85 MGD
BOD5 summer
2.8 mg/L*
4.2 mg/L
BOD5 winter
5.6 mg/L
8.4 mg/L
NH3 as N summer
0.7 mg/L
2.1 mg/L
NH3 as N winter
1.4 mg/L
4.2 mg/L
Dissolved Oxygen
Not less than 5.0 mg/L, daily average
TSS
30 mg/L
45 mg/L
TRC
28 ug/L
Fecal coliform (geometric mean)
200/100 ml
400/100 ml
Chronic Toxicity Pass/Fail
jQuarterly test)
21%
*Note: BOD5 limit of 2.8 mg/L are most likely not sustainable and may be considered not
technologically -feasible. More detailed review of the final design would be required.
Engineering Alternatives Analysis (EAA). Please note that the Division cannot guarantee that an
NPDES permit for an expanded discharge will be issued with these speculative limits. Final decisions
can only be made after the Division receives and evaluates a formal permit application for the
expanded discharge. In accordance with the North Carolina General Statutes, the practicable
wastewater treatment and disposal alternative with the least adverse impact on the environment is
required to be implemented. Therefore, as a component of all NPDES permits applications for new or
expanding flow, a detailed engineering alternatives analysis (EAA) must be prepared. The EAA must
justify requested flows and provide an analysis of potential wastewater treatment alternatives
including justification for not connecting to the City of Hickory WWTP. A copy of Division guidance
for preparing EAA documents is attached.
State Environmental Policy Act (SEPA) EA/EIS Requirements. A SEPA EA/EIS document must be
prepared for all projects that: 1) need a permit; 2) use public money or affect public lands; and 3) might
have a potential to significantly impact the environment. For existing discharges, significant impact is
defined as an expansion of > 500,000 gpd additional flow. Since Claremont is proposing expansions <
500,000 gpd flow, the SEPA document and evaluation are not required.
Should you have any questions about these speculative limits or NPDES permitting requirements,
please feel free to contact Ron Berry at [phone] or Tom Belnick at [phone].
Respectfully,
Tom Belnick
Supervisor, NPDES Complex Permitting Unit
cc:
Mooresville Regional Office/Surface Water Protection
Kathy Stecker/Modeling TMDL Unit
Central Files
NPDES Permit Files/NC0032662 and NC0081370
Page 3 of 3

DIVISION OF ENVIRONMENT MANAGEMENT
March 21,1994
MEMORANDUM
TO: Ruth Swanek
Steve Bevington
FROM: Jacquelyn M. Nowell/so,.
SUBJECT: Lyle Creek Management Strategy
This strategy was developed in 1988 when the Town of Conover -Northeast
(discharging into Lyle Creek) requested an expansion to 1.5 MGD. The Lyle Creek
watershed has several other municipalities discharging into the system, Pine Ridge
Subdivision, Bunker Hill H.S., Claremont North (Huffman Branch), Claremont South
(UT McLin Creek), Conover SE (McLin Creek), Witherspoon Crossroads (Hagans Fork),
and the Town of Catawba (Lyle Creek ). Level B model results for the Conover expansion
showed interaction between the dischargers and predicted a DO minimum of 5 mg/l
downstream,below the Town of Catawba near the mouth of Lyle Creek. The limits
developed in 7/88 for Conover NE to protect the DO standard were 8/2/5 and 16/4/5.
After consultation with supervisors (Trevor Clements and Dave Vogt), it was
decided to assign the same limits to proposed and expanding facilities in the Lyle Creek
watershed because of the potential for water quality problems in the backwaters of Lake
Norman (mouth of Lyle Creek). This strategy has been implemented since 1989 for any
expanding or proposed discharger in the basin. Facilities that have received 8/2/5 and
16/4/5 limits based on this strategy are Claremont -Southwest (permit rescinded due to lack
of construction), Rock Barn Properties (renewed 2/94) and proposedClaremont-McLin
Creek WWTP.
In May, 1991, Tech Support responded to Construction Grants that The Town of
Claremont - South WWTP upon expansion could receive 1) existing BOD5 loading
capacity or 2) limits equivalent to Conover NE WWTP (8/2/5 & 16/4/5).
Attached is the original model run for the Conover NE expansion, based on the DO
minimum of 5 mg/1 in the last reach just before entering Lake Norman, Tech Support had
implemented the 82/5 limit strategy.
cc: WLA File

inC.LikGyvtif
rrlJ // Crrf�'
Ly/1e'CveK _(hNui,
/
Conover NE WWTP
1.5 MGD
BOD= 8/16
NH3 =2/4
DO =5
Pine Ridge Subdivision WWTP
0.02 MGD (inactive)
BOD=30
NH3=MONITORED
DO=NO REQUIREMENTS
•
C00 0872
UPS Ground (Overnite) WWTP
0.003 MGD (inactive)
BOD=30
NH3=MONITORED
DO=NO REQUIREMENTS
Conover SE WWTP
0.3 MGD
BOD=30
NH3=2/5.2
DO=5
Claremont North WWTP
0.1 MGD l I
BOD=30
NH3=MONIT fifE—'
DO=5
CATAWBA RIVER BASIN, LYLE CREEK SUBBASIN NPDES PERMITS AS OF 4/29/11
Bunker Hill HS WWTP
0.015 MGD
BOD=16/30
NH3=4.3/15
DO=6
Catawba WWTP
0.225 MGD
BOD=30
NH3=MONITORED
DO=NO REQIREMENTS
Country Valley WWTP
0.1 MGD
BOD=8/16
NH3=5.3/10
DO=MONITORED
`r ' _ (ti..` .. i t rr. ,.

.0ovtsw e 44 'I
Belnick, Tom
From: Belnick, Tom
' Sent: Thursday, November 08, 2012 3:58 PM
To: Behm, Pamela
Cc: Berry, Ron; Parker, Michael
Subject: RE: City of Hickory - Lyle Creek Expansion Model Review
zu rz,„
Crs 4')I,4&)1»
,ite4- LI(46'mmt
Pam- I talked with Claremont's modeler Ken Hickey with HydroAnalysis- told him I was a
"middle man" in this process. Relayed your thoughts about submitting a modeling analysis
plan, which he thought was good idea. He might call you with questions.
Ron- fyi. Modeling Unit will take lead with this possible extension of WASP model to
evaluate Claremont expansion. If modeling results are positive, we might need to issue
another spec letter down the road.
Mike- fyi. Claremont evaluating possibility of expansion, based on impasse with connection
to Hickory/Catawba WWTP.
Tom Belnick
Supervisor, NPDES Complex Permitting Unit NCDENR/Division of Water Quality
919-807-6390
E-mail correspondence to and from this address may be subject to the North Carolina Public
Records Law and may be disclosed to third parties
Original Message
From: Behm, Pamela
Sent: Thursday, November 08, 2012 12:02 PM
To: Belnick, Tom
Subject: FW: City of Hickory - Lyle Creek Expansion Model Review
Original MTU comments on Lyle Creek model are attached. The consultant for Claremont has the
model and report. I would suggest that you require that Claremont submit a modeling analysis
plan to NPDES to describe how they would intend to use the model to evaluate the impact of
their discharge. We will review this plan. I expect there may need to be some modification
to the model to more explicitly represent McLin Creek in order to evaluate local impact.
***************************************************************
Pam Behm
NC DWQ Modeling and TMDL Unit
1617 Mail Service Center
Raleigh, NC 27699
Email: pamela.behm(tncdenr.gov
Phone: [phone]
Fax: [phone]
E-mail correspondence to and from this address may be subject to the North Carolina Public
Records Law and may be disclosed to third parties.
Original Message
From: Pam Behm[mailto:pamela.behm(alncmail.net]
Sent: Thursday, May 22, 2008 1:45 PM
1

To: Susan Wilson; Sergei Chernikov; Jackie Nowell; Kathy Stecker; Hannah Stallings;
dianne.reid
Subject: City of Hickory - Lyle Creek Expansion Model Review
Hello everyone,
Attached is the review of the Lyle Creek Model developed by ENSR to assess the feasibility of
an expansion of the Hickory Catawba WWTP from
0.225 MGD to 3.0 MGD. The way this memo is written, you will need to have the report and
memorandum submitted by ENSR to refer to specific pages and figures.
Hannah and Dianne- I included you on this because.I know you are involved with the EA part of
this.
Let me know if you have any questions. Thanks.
Pam
2

NC Division of Water Quality
Planning Section — Modeling & TMDL Unit
Technical Memorandum
May 22, 2008
TO: Kathy Stecker, Modeling and TMDL Unit
FROM: Pam Behm, Modeling & TMDL Unit
CC: Susan Wilson, Western NPDES Unit
Sergei Chernikov, Western NPDES Unit
Jackie Nowell, Western NPDES Unit
Dianne Reid, Basinwide Planning Unit
Hannah Stallings, Basinwide Planning Unit
Trish MacPherson, Biological Assessment Unit
RE: Lyle Creek WASP Model Review
The Modeling and TMDL Unit (MTU) has reviewed the documentation listed below to
evaluate the effect of a 3.0 MGD discharge from Catawba WWTP (NC0025542) on
dissolved oxygen (DO) concentrations in Lyle Creek. A summary of the MTU's review is
provided below:
1. Documentation:
a. Wasteload Allocation Study for the Hickory Catawba WWTP, Catawba North
Carolina (ENSR - Dec. 2007) - The initial modeling report submitted to DWQ.
b. Memorandum from Ken Heim, ENSR to Pam Behm, DWQ, April 24, 2008,
Subject: Comments Regarding the WASP Model of the Catawba River - After
initial review of the December 2007 report, MTU reported to the Western NPDES
Unit that the report was not complete as submitted and more information was
needed to evaluate the model. ENSR responded with the memorandum.
c. DVD containing model input files: "Lyle Creek Model DYNHYD/WASP Input
files 12401-001 ", ENSR 4/28/08 — Submitted to DWQ with the memorandum in
response to an MTU comment that DWQ should have all relevant model files.
2. Limitations and Uncertainty:
As always, there is uncertainty associated with interpretation of the model results.
Uncertainty results from: (1) limitations within the WASP model framework, (2)
assumptions made during model development, and (3) model calibration.
Limitations specific to the Lyle Creek Model include: (1) the modeling time period is
less than a month, although the time period does represent worst case conditions
(August 2007, during a drought), (2) there are limited data points available for

calibration, and (3) calibration results were provided for 2 out of the 7 monitoring
stations.
Pages 3-18 to 3-20 of the December 2007 Report document the results of model
calibration, with the DO calibration provided on page 3-20. Model predictions are
vertically averaged and represent average DO throughout the water column. The
difference between measured and predicted DO is as high as 1.5 mg/L at times.
In order to better understand the uncertainty associated with the model predictions,
ENSR provided a sensitivity analysis in the memorandum at DWQ's request. ENSR
evaluated the sensitivity of model predictions to changes in several key parameter
rates. The most sensitive parameter is the sediment oxygen demand rate, which is
estimated from ranges found in literature to be 4.0 g/m /day in the model. See Figure
7A in the memorandum for the results of the sensitivity analysis.
The MTU recognizes the complexity of the analysis done to develop the Lyle Creek
Model. Significant fieldwork was performed to provide site -specific information for
model development. This included dye studies, collection of chemical and physical
parameters, and flow gages. However, due to the limited number of data points,
sufficient conclusion on the accuracy of the calibration and the level of uncertainty
cannot be determined. Therefore the interpretation of model results and
determination of speculative limits should be viewed carefully in light of this
limitation.
3. Results of Loading Scenarios:
Three loading scenarios based on possible permit limits for a discharge of 3.0 MGD
were evaluated for this effort. Details on the three scenarios are provided in the
December 2007 Report on pages 4-1 and 4-2. Results of the three scenarios at
monitoring station LC7 (Lyle Creek near mouth) are provided in Figure 4-1 (page 4-3
of the report). As shown in Figure 4-1, Scenarios 1 and 2 both result in DO
concentrations below 5.0 mg/L at times during the model runs, while DO remains
above 5.0 mg/L for Scenario 3. Therefore, Scenario 3, 3.0 MGD flow with limits
consistent with tertiary treatment and effluent aeration, is the most viable option for
consideration of an expansion of discharge into Lyle Creek.
The December 2007 Report provided modeling results only at station LC7, which is
the most downstream monitoring station. The memorandum (mentioned above in
bullet lb) resulted from DWQ's initial response that impacts of the discharge should
be evaluated throughout Lyle Creek, not just at the most downstream monitoring
station. The memorandum contains plots of DO longitudinally (Figure 1A) and as a
time -series at each monitoring station (Figures 2A-6A). At no point in the modeling
time period does Scenario 3 result in DO below 5.0 mg/L.
Figure 1 provided below shows the locations of the monitoring stations and their
associated model segments. Figures 2-9 provided below contain additional plots
comparing current conditions (referred to as "calibration") with Scenario 3. MTU
generated these figures using the model input files provided by ENSR.

It should be noted that, as shown in Figure 1 A of the memorandum and in Figures 8-9
below, DO decreases longitudinally to just above 5.0 mg/L at the confluence with the
Catawba River. The model predicts downstream DO concentrations will be higher
than current conditions for Scenario 3, however the decreasing DO trend remains (see
Figures 8-9 below). In addition, reversing flows occur in Lyle Creek due to
hydropower dam releases. Because of this, MTU recommends that if speculative
limits are issued for this discharge, there should be frequent monitoring at this
downstream site to ensure that DO levels do not fall below 5.0 mg/L.
4. The model was not evaluated for nutrients (e.g. total phosphorus (TP) and total
nitrogen (TN)). This discharge is not far from the confluence of Lyle Creek with the
Catawba River/Lake Norman and the expansion to 3.0 MGD represents a huge
increase from the current flow and potential nutrient load coming into Lake Norman
from Lyle Creek. Therefore, to protect Lake Norman from degradation, MTU
recommends that if speculative limits are issued, the Western NPDES Unit should
consider the current and future TP and TN loads, and issue appropriate limits on both
TP and TN.
5. MTU is concerned about the effect of the increased discharge on the channel
morphology of Lyle Creek and the quality of the benthic community. This expansion
will result in a permitted flow that is 13 times greater than what is currently
permitted. Flows in Lyle Creek were calculated to be 4.8 cfs on 8/20/07 at Station
LC2, which is just upstream of the discharge. This equates to about 3.1 MGD. So, in
essence, a permitted discharge at 3.0 MGD will double the in -stream flow under
similar flow conditions.
DWQ should ensure that such a significant increase in flow does not increase erosion
of the stream banks and impact the benthic community. MTU recommends that the
DWQ Environmental Sciences Section (particularly Biological Assessment) have the
opportunity to comment on the possible effect of the increase in discharge on the
stream morphology and the condition of the benthic community.
6. MTU's interpretation of model results is based on model documentation and review
of model input files. Specific questions about model development should be directed
to ENSR.

J �,
/ f
1, i
l \
Upstream Variable Flow,..,.
Model Boundary
'LC1
•
•
Trn Transact 0113100
TI T1/LCIA 0
T2 100
73 200
T4 300
75 400
76 500
77 600
TO 700
79 800
T10 900
711 72 1000
712 1100
113 1200
T14 1300
716 1400
T16 1500
717 1000
T18 1700
T19 1800
720 1900
7 721 73 2000
722 20'.ro
T23 2100
724 2150
T25 2200
T26 2250
727 2300
T28 2350
T29 2400
T30 2450
Trn Transact Dlat (11)
731 2600
732 2560
T33 2600
734 2650
735 2700
T36 2750
737 2600
738 2850
739 2000
T40 2960
741 74 2000
742 3050
743 3100
744 3160
745 3200
746 3250
T47 3300
748 3350
749 3400
750 3450
751 3500
752 3560
T53 3600
754 3650
755 3700
766 3760
757 3800
758 3860
T59 3500
760 2650
Trn Transact 01st(It)
1121 711 10000
7122 10100
7123 10200
1124 10300
T126 10400
T126 10500
T127 LC2 10060
7128 10700
7129 10800
T130 10900
T131 T12 11000
T132 11100
T133 11200
T134 11300
7135 LC3 11400
T136 11500
7137 11600
1.130 11700
` 1
_MC9_ McClin Creek Variable
Flow Tributary Boundary
,•' T
• Trn Transact 01s1(11)
T61 TS 4000
762 4100
T63 4200
764 4300
765 4400
766 4500
T67 4600
T68 4700
769 4800
T70 4900
771 76 5000
772 5100
773 5200
774 5300
775 5400
T76 5500
T77 5600
778 5700
T79 5500
780 5900
Trn Transco 013t(6)
7130 1800
T140 1900
T141 713 2000
7142 2100
T143 2200
7144 2300
7145 LC4 2400
7146 2500
T147 2600
7148 2700
7149 2800
7150 2900
7151 714 3000
T162 3100
7163 LC5 3200
7154 3300
7155 3400
T156 3500
T157 3600
T158 3700
T159 3800
7160 311100
1161 715 4000
7162 4100
7163 420)
T164 4300
7165 4400
7166 4500
T167 LC6 4600
T160 4700
T169 4800
T170 4900
Trn Transact DIM(n)
T81 77 6000
782 6100
783 6200
784 6300
785 6400
786 0500
T87 6600
T88 6700
789 6800
T90 6900
791 78 7000
792 7100
793 7200
T54 7300
795 7400
T08 7600
797 7600
T98 7700
799 7800
7100 7900
Y0
)
Trn Transact 01s1(11)
T171 716 16000
7172 15100
7173 15200
T174 15300
T175 LC7 15400
7176 15500
T177 15600
7178 15700
T179 15800
T180 15500
7181 T17 18000
T182 16100
7183 T18 16200
Trn Tranascl Dlst(It)
7101 Ti 8000
T102 8100
7103 8200
7104 6500
T105 841:0
7106 8544
7107 8600
T108 8700
7109 6000
7110 8900
7111 710 9040
T112 9100
7113 9200
T114 9306
T115 9400
7116 9500
1117 9600
7116 9700
7119 9800
7120 9900
,•�. '—�;90b?i 4,000
1 •Feet
Transects and Sampling Station Locations
"Trn" Numbers are Coincident with WASP Segment Numbers
Figure 1. Model segmentation and locations of monitoring stations.
IP

8.5
8
7.5
ij;
7
O 6.5
6
5.5
5
7/31
DO - Segment 151 (at the discharge)
8/4 8/8 8/12
Date (2007)
- Calibrated Scenario 3
8/16
8/20
Figure 2. DO (mg/L) at Segment 151, the location of the discharge. Calibrated refers to
conditions as they existed in August 2007 and Scenario 3 represents the expansion to 3.0 MGD
with tertiary treatment and DO of 6.0 mg/L.
8.5
8
7.5
7
O 6.5
6
5.5
5
DO - Segment 153 (below the discharge)
7/31 8/4 8/8 8/12 8/16 8/20
Date (2007)
- Calibrated Scenario 3
Figure 3. DO (mg/L) at Segment 153, downstream of the discharge.

Figure 4. DO (mg/L) at Segment 164.
Figure 5. DO (mg/L) at Segment 175, the location of monitoring station LC7.

8.5
8
7.5
7
J
5) 6.5
O 6
5.5
5
4.5
DO -Segment 181
I/
4
7/31 8/4 8/8 8/12 8/16 8/20
Date (2007)
- Calibrated Scenario 3
Figure 6. DO (mg/L) at Segment 181.
8.5
8.0
7.5
7.0
- J
'irn 6.5
O 6.0
0
5.5
5.0
4.5
4.0
DO - Segment 182 (at Catawba R.)
JI
7/31 8/4 8/8 8/12
Date (2007)
- Calibrated Scenario 3
8/16 8/20
Figure 7. DO (mg/L) at Segment 182, at the Catawba River.

8.5
8.0
7.5
J 7.0
Of
E 6.5
0
0 6.0
5.5
5.0
4.5
DO Longitudinal Profile 8/9/07
Hickory WWTP
Discharge
1
0 20 40 60 80 100
Segment
120
Calibrated Scenario 3
140
160
180
Figure 8. DO longitudinal profile for 8/9/07 at 10:36.
9.0
8.5
8.0
7.5
J
`a) 7.0
E
0 6.5
0
6.0
5.5
5.0
4.5
DO Longitudinal Profile 8/14/07
Hickory WWTP
Discharge
0 20 40 60 80 100
Segment
120
Calibrated Scenario 3
140
160
180
Figure 9. DO longitudinal profile for 8/14/07 at 15:24.

7� 11 S'e c Om /
AVA
NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins
Governor Director
May 4, 2011
Mr. Doug Barrick
City Manager
City of Claremont
P. O. Box 446
Claremont, NC 28610
Dee Freeman
Secretary
Subject: Speculative Effluent Limits
Claremont WWTPs
Permits NC0032662 and NC0081370
Catawba County
Catawba River Basin
Dear Mr. Barrick:
This Ietter provides speculative effluent limits for 0.25 MGD at the Claremont North WWTP, which is
currently permitted at 0.10 MGD, and for 0.60 MGD and 0.85 MGD at the Claremont McLin Creek WWTP,
which is currently permitted at 0.30 MGD. The Division received the speculative limits request in a letter
dated March 2, 2011 from William S. Clayton of Davis & Floyd, Inc. Please recognize that speculative limits
may change based on future water quality initiatives, and it is highly recommended that the applicant verify
the speculative limits with the Division's NPDES Unit prior to any engineering design work.
Receiving Streams. Mull Creek, the receiving stream for Claremont North WWTP, and McLin Creek,
the receiving stream for Claremont McLin Creek WWTP, both flow into Lyle Creek and are part of the
Lyle Creek watershed within the Catawba River Basin. Lyle Creek discharges into Lake Norman. Mull
Creek and McLin Creek have stream classifications of WS-IV and WS-IV CA, respectively. Waters with
the WS-IV classification have a best usage as a water supply for drinking, culinary, or food -processing
purposes and for aquatic life propagation and maintenance of biological integrity, wildlife, secondary
recreation and agriculture. The CA classification applies additional Nonpoint Source and Stormwater
Pollution Control Criteria. Mull Creek has a summer 7Q10 flow of 1 cfs, a winter 7Q10 flow of 1.6 cfs,
and an annual average flow of 5 cfs. McLin Creek has a summer 7Q10 flow of 5 cfs, a winter 7Q10 flow
of 9 cfs, and an annual average flow of 26 cfs.
Speculative Effluent Limits. Based on Division review of receiving stream conditions, the Lyle Creek
Watershed Management Strategy, and other water quality modeling results, speculative limits were
developed. The proposed expansion to 0.25 MGD at Claremont North WWTP is presented in Table 1.
Page 1 of 3
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Location: 512 N. Salisbury St. Raleigh, North Carolina 27604
Phone: [phone] FAX: [phone] Customer Service: 1-877-623-6748
Internet: www.ncwaternuality.orq
NorthCarolina
Naturally

The proposed expansions to 0.60 MGD and 0.85 MGD at Claremont McLin Creek WWTP are presented
in Tables 2 and Tables 3, respectively. A complete evaluation of these limits and monitoring
requirements for metals and other toxicants, as well as potential instream monitoring requirements,
will be addressed upon receipt of a formal NPDES permit application.
A feature of the speculative limit development include the following:
• BOD/NH3/DO Limits. The Lyle Creek Management Strategy was developed to establish BOD,
NH3, and DO limits for new or expanding dischargers in the Lyle Creek watershed so the dissolved
oxygen water quality standard would be met in Lyle Creek prior to discharge into Lake Norman. In
the case of the Claremont McLin Creek WWTP, the strategy limits had already been applied so any
future expansion will be based on freezing current permitted BOD and ammonia loads (i.e., facility
will not be allowed to discharge oxygen -consuming waste above what is currently permitted). The
resultant limits at expanded flows of 0.25 MGD (Table 1) and 0.60 MGD (Table 2) are considered
technologically -feasible.
TABLE 1: Speculative Limits for Claremont North WWTP (Proposed Expansion to 0.25 MGD)
Effluent Characteristic
Effluent Limitations
Monthly Average
Weekly Average
Daily Maximum
Flow
0.25 MGD
_
BOD5 summer
8.0 mg/L
12.0 mg/L
BOD5 winter
16.0 mg/L
24.0 mg/L
NH3 as N summer
2.0 mg/L
6.0 mg/L
_
NH3 as N summer
4.0 mg/L
12.0 mg/L
Dissolved Oxygen
Not less than 5.0 mg/L, daily average
TSS
30 mg/L
45 mg/L
TRC
28 ug/L
Fecal coliform (geometric mean)
200/100 ml
400/100 ml
Chronic Toxicity Pass/Fail
(Quarterly test)
28°r6
TABLE 2: Speculative Limits for Claremont McLin Creek WWTP (Proposed Expansion to 0.60 MGD)
Effluent Characteristic
Effluent Limitations
Monthly Average
Weekly Average
Daily Maximum
Flow
0.60 MGD
BOD5 summer
4.0 mg/L
6.0 mg/L
BOD5 winter
8.0 mg/L
12.0 mg/L
NH3 as N summer
1.0 mg/L
3.0 mg/L
NH3 as N winter
2.0 mg/L
6.0 mg/L
Dissolved Oxygen
Not less than 5.0 mg/L, daily average
TSS .
30 mg/L
45 mg/L
TRC
28 ug/L
Fecal coliform (geometric mean)
200/100 ml
400/100 ml
Chronic Toxicity Pass/Fail
(Quarterly test)
16%
_
Page 2 of 3

TABLE 3: SpecuIative Limits for Claremont McLin Creek WWTP (Proposed Expansion to 0.85 MGD)
Effluent Characteristic
Effluent Limitations
Monthly Average
Weekly Average
Daily Maximum
Flow
0.85 MGD
BOD5 summer
2.8 mg/L*
4.2 mg/L
BOD5 winter
5.6 mg/L
8.4 mg/L
NH3 as N summer
0.7 mg/L
2.1 mg/L
"
NH3 as N winter
1.4 mg/L
4.2 mg/L
Dissolved Oxygen
Not less than 5.0 mg/L, daily average
TSS
30 mg/L
45 mg/L
TRC
28 ug/L
Fecal coliform (geometric mean)
200/100 ml
400/100 ml
Chronic Toxicity Pass/Fail
(Quarterly test)
21%
_
ote: BODS limit of 2.8 mg%L are most likely not sustainable and may be considered not
technologically -feasible. More detailed review of the final design would be required.
Engineering Alternatives Analysis (EAA). Please note that the Division cannot guarantee that an
NPDES permit for an expanded discharge will be issued with these speculative limits. Final decisions
can only be made after the Division receives and evaluates a formal permit application for the
expanded discharge. In accordance with the North Carolina General Statutes, the practicable
wastewater treatment and disposal alternative with the least adverse impact on the environment is
required to be implemented. Therefore, as a component of all NPDES permits applications for new or
expanding flow, a detailed engineering alternatives analysis (EAA) must be prepared. The EAA must
justify requested flows and provide an analysis of potential wastewater treatment alternatives
including justification for not connecting to the City of Hickory WWTP. A copy of Division guidance
for preparing EAA documents is attached.
State Environmental Policy Act (SEPA) EA/EIS Requirements. A SEPA EA/EIS document must be
prepared for all projects that: 1) need a permit; 2) use public money or affect public lands; and 3) might
have a potential to significantly impact the environment. For existing discharges, significant impact is
defined as an expansion of > 500,000 gpd additional flow. Since Claremont is proposing expansions <
500,000 gpd flow, the SEPA document and evaluation are not required.
Should you have any questions about these speculative limits or NPDES permitting requirements,
please feel free to contact Ron Berry at [phone] or Tom Belnick at [phone].
cc:
Mooresville Regional Office/Surface Water Protection
Kathy Stecker/Modeling TMDL Unit
Central Files
NC0032662 and NC0081370
NPDES Permit Files/
Re pectfully,
om Belnick
Supervisor, NPDES Complex Permitting Unit
S-ez_ 9nC®®324L2
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Page 3 of 3