NC0081621_Speculative Limits_20160401

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Belnick, Tom fb� O' �/ � � "�°' �%j''r��
From: Belnick, Tom 6 V
Sent: Friday, April 08, 2016 11:19 AM V
To: 'Chuck Willis' � / /
Subject: NPDES/Spec WSACC Muddy Creek 3
Attachments: NCO081621 spec 2007.pdf
Chuck —see attached 2007 spec for 1/2/5/MGD. Results are still valid.
Tom Belnick
Supervisor
NPDES Complex Permitting Unit, DWR
North Carolina Department of Environmental Quality
919-807-6390 office
[e-mail]
512 North Salisbury Street
1617 Mail Service Center
Raleigh, NC 27669
N
!--'`Nothing Compares---,,_ IP
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
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Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
a.
November , 2007
Mr. Van Rowell
Water & Sewer Authority of Cabarrus County
P.O. Box 428
Concord, North Carolina 28026-0428
Coleen H. Sullins, Director
Division of Water Quality
Subject: Speculative Effluent Limits
WSACC Muddy Creek WWTIINC0081621
Proposed Expansion'��
Cabarrus County "
Dear Mr. Rowell:
This letter is in response to your request for speculative effluent limits for a proposed expansion of Muddy Creek
WWTP from 0.3 MGD to 5.0 MGD of wastewater discharging to the Rocky River.
Receiving Stream: Muddy Creek WWTP discharges into the Rocky River. This segment of the Rocky River is
classified C waters. It should be noted that the Rocky River is impaired for turbidity. Therefore, any expansion
should not have any further impact on the turbidity in the Rocky River.
Speculative Limits: The speculative limits were developed based on an EPA -approved QUAL2E model on the
Rocky River. The model was run for Muddy Creek WWTP at the current permitted discharge of 0.3 MGD and the
proposed expansions to 5.0 MGD.
Based on available information, speculative effluent limits for the proposed discharges of 1.012.015.0 MGD to the
Rocky River are presented in Table 1. A complete evaluation of these limits and monitoring frequencies in
addition to monitoring requirements for metals and other toxicants, will be addressed upon receipt of a formal
NPDES permit application request.
The model results indicate that 1.0/2.0/5.0 MGD discharges with the speculative limits presented in Table 1 will
have minor impacts on the dissolved oxygen levels in the river and will not lower the levels below the water quality
standard of 5 mg/L.
TABLE 1. Speculative Limits for Proposed Fxnansinns
Effluent Characteristic=
Flow
Effluent Limitations
Month l Average
1.0/2.0/5.0 MGD
VI/eekl Avera a "" .
Dail Maximum
f
BOD5i A ril 1 _Oct ober 31
5.0 mg/I
7.5 mg/1
BOD5i November 1 — March 31
10.0 mg/I
15.0 mg/I
Total Suspended Solids
30.0 mg/I
45.0 mg/I
NH3 as N, (April 1 —October 31
1.0 mg/I
3.0 mg/I
NH3 as N, November 1 — March 31
2.0 mg/I
6.0 mg/I
TRC
Fecal coliform geometric mean
200/100 ml
400/100 ml
28.0 ug/I
Engineering Alternatives Analysis (EAA): Please note that the Division cannot guarantee that an NPDES permit
for an expansion to 1.0/2.0/5.0 MGD will be issued. Final decisions can only be made after the Division receives
and evaluates a formal permit application for Muddy Creek WWTP's proposed expansion.
N1,11VIly
nehCarolina
North Carolina Division of Water Quality 1617 Mail Service Center Raleigh, NC 27699-1617 Phone [phone] Customer Service
Internet: www.ncwaterquality.org Location: 512 N. Salisbury St. Raleigh, NC 27604 Fax [phone]
An Equal Opportunity/Affirmative Action Employer — 50% Recycled/10% Post Consumer Paper

Mr. Lane
Page 2 of 2
In accordance with the North Carolina General Statutes, the most 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 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.
Alternatives to a surface water discharge, such as spray/drip irrigation, wastewater reuse, or inflow/infiltration
reduction, are considered to be environmentally preferable. A copy of the EAA requirements is attached to this
letter. Permit applications for new or expanding flow will be returned as incomplete if all EAA
requirements are not adequately addressed. If you have any questions regarding these requirements, please
contact the DWQ NPDES Unit at 919-733-5083.
State Environmental Policy Act (SEPA) EA/EIS Requirements: A SEPA EA or 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 wastewater discharges, significant impact is defined as a proposed
discharge of >500,000 gpd and producing an instream waste concentration of > 33% based on summer 7Q10
flow conditions. For existing discharges, significant impact is defined as an expansion of > 500,000 gpd additional
flow. Since the proposed discharge is an existing discharge with expansion of >500,000 gpd flow,
WSACC must prepare a SEPA document that evaluates the potential for impacting the quality of the
environment. The NPDES Program cannot 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). Since your proposed discharge is 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 Hannah Stallings with the DWQ Planning Branch at [phone], ext.
555.
Should you have any questions about these speculative limits or NPDES permitting requirements, please feel free
to contact Agyeman Adu-Poku at [phone], extension 508.
Sincerely,
Susan A. Wilson, P.E.
Supervisor, Western NPDES Program
Attachment: EAA Guidance Document
cc: (without Attachment)
DWQ Mooresville Regional Office/Surface Water Protection Section
Central Files
NPDES Permit File
McKIM & CREED, P.A./Keith E. Lane, P.E.
200 MacKenan Court
Cary, NC 27511
NC Wildlife Resources Commission, Inland Fisheries/Fred Harris
1721 Mail Service Center
Raleigh, NC 27699-1721
US Fish & Wild Life/Tom Augspurger
P.O. Box 33726
Raleigh, NC 27636

NC Division of Water Quality
Planning Section — Modeling & TMDL Unit
Technical Memorandum
October 25, 2007
TO: Toya Fields, Western NPDES Unit
CC: Kathy Stecker, Modeling & TMDL Unit
Susan Wilson, Western NPDES Unit
FROM: Pam Behm, Modeling & TMDL Unit
RE: WSACC Muddy Creek WWTP Speculative Limits — QUAL2E Model Simulation
NPDES Permit Number: NCO081621
This is in response to your request for speculative limits for a proposed expansion of the Muddy
Creek Wastewater Treatment Plant (WWTP) from 0.3 MGD to 5.0 MGD. The Rocky River
QUAL2E model, which is a low -flow, steady-state, and one-dimensional BOD model, was used
to evaluate the effect of the requested expansion on dissolved oxygen (DO) concentrations in the
Rocky River. A map of the area is provided in Figure 1.
The QUAL2E model extends 73.4 miles from Dye Branch to the USGS gage (02126000) just
below Lanes Creek near the Town of Norwood, The oldest portion of the QUAL2E model is the
upstream portion and extends 42.8 miles downstream to just below the confluence of Muddy
Creek, This portion of the model is actually a combination of three individual QUAL2E models,
which were developed for wasteload allocation. These three models are: the Mooresville
WWTP model completed in 1988, the Mallard Creek WWTP model, completed in 1992, and the
Concord Regional WWTP model, also completed in 1988. The downstream model was
developed in 2001 to extend the model down to the USGS gage in Norwood.
When the downstream model was developed, it was combined with the upstream model, but the
upstream model was not recalibrated. This means the upstream model is about 20 years old and
is based on 20-year old flow regimes. The downstream model was developed and calibrated
using very little monitoring data, although there is good time -of -travel and long term BOD data.
Most of the other parameters were estimated from data collected during one -sampling trip in
May. I am particularly concerned that tributary inputs to the Rocky are not fully accounted for in
the model. For these reasons, the Rocky River QUAL2E model is in need of recalibration and
extreme care should be taken in interpreting model results.
The model was run for the Muddy Creek WWTP current permitted discharge of 0.3 MGD and
the proposed expansion to 5.0 MGD. This discharge occurs at about river mile 43 in the model.
Figure 2 shows the simulated dissolved oxygen (DO) levels for the two different scenarios. The
model results indicate that a 5.0 MGD discharge with a monthly average BOD limit of 5 mg/i
and a monthly average ammonia limit of 1 mg/l will have minor impacts on the DO levels in the
river, but will not lower the levels below 5 mg/1. Although the model results indicate that

dissolved oxygen in the river would most likely meet water quality standards, the predicted
dissolved oxygen levels should be interpreted with caution. These levels would depend on flows
from tributaries and other WWTPs discharging to the Rocky River and the current river
conditions.
Analyses of dissolved oxygen data from 2000-2006 from various stations along the Rocky River
are provided in Figures 3-12. Stations Q8210000, Q8355000, and Q8385000 exhibit DO
concentrations below the standard of 5 mg/L during the summer months. The low DO values at
Station Q8385000 are of particular concern because this station is right below the Muddy Creek
WWTP discharge. If there is an expansion of the Muddy Creek WWTP, the permit should
contain the requirement of at least weekly monitoring of DO concentrations at this station.
It should be noted that the Rocky River is impaired for turbidity. Therefore, any expansion
should not have any further impact on the turbidity in the Rocky. River.
As part of the speculative limits request, there was also a request to determine the speculative
maximum discharge that may be permissible assuming that the plant is upgraded to best practical
technology for BOD and Ammonia removal. Due to the age of the model and the associated
uncertainties, the Rocky River QUAL2E model is not an adequate tool to determine the
maximum discharge that may be permissible.
The Rocky River QUAL2E model -reeds to be recalibrated and updated to current conditions
prior to considering any further speculative limit discharge requests. The model should also be
extended down to the confluence of the Rocky River and the Pee Dee River. The current model
ends at the USGS gage in Norwood and shows DO decreasing (see Figure 2). It is important to
extend the model further downstream to see if the DO recovers before it reaches the Pee Dee
River, which is impaired for low DO.
If the dischargers in this area are working together to develop a regional plan (as recommended
by DWQ earlier this year), perhaps they can include updating and expanding the QUAL2E
model as part of their planning process. This will provide the dischargers with a tool to test
various scenarios as they work towards developing a regional plan. The Modeling and TMDL
Unit can provide guidance and review of the model.
If you have any questions please contact me at 919-733-5083 ext. 506.
2

Belnick, Tom
From: Belnick, Tom
Sent: Tuesday, December 22, 2015 10:32 AM
To: Behm, Pamela
Cc: Rodriguez, Teresa (Teresa. Rod rig [e-mail]); Kebede, Adugna
Subject: RE: WSACC Muddy Creek Spec NCO081621
Thanks Pam. NPDES will probably need to regroup with Modeling in 2016 to discuss this spec request further. Below is
a statement I made in a prior email on this spec request:
"The 2015 request included updated USGS flow statistics, which are quite different from flows used in 1992 Level B
modeling; however, much of this can be attributed to significant differences in calculated drainage areas (553 sq miles vs
384 sq miles). "
Yesterday I asked Teresa to check DA using USGS StreamStats, and she confirmed that DA= 553 sq miles, so DWQ was
using smaller DA/smaller 7Q10's in prior modeling for this stretch of Rocky River.
Tom Belnick
Supervisor
NPDES Complex Permitting Unit, DWR
North Carolina Department of Environmental Quality
919-807-6390 office
[e-mail]
512 North Salisbury Street
1617 Mail Service Center
Raleigh, NC 27669
-5:->^Nothin9 Compares
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
From: Behm, Pamela
Sent: Tuesday, December 15, 2015 12:15 PM
To: Belnick, Tom <[e-mail]>
Subject: FW: WSACC Muddy Creek Spec NCO081621
Tom,
See Adugna's recommendation below

From: Kebede, Adugna
Sent: Tuesday, December 15, 2015 12:00 PM
To: Behm, Pamela <[e-mail]>
Subject: RE: WSACC Muddy Creek Spec NC0081621
Hi Pam,
I reviewed the documents. I also went back and checked the 2007 model and rerun the model for 1 MGD expansion with
BOD limit of 5 mg/I and ammonia limit of 2 mg/I to see if the will be any change and the results are similar to the finds of
the 2007 report — no impact. It appears to me that there is no need to require them to update the model based on
their current request. Though we should still have the same concerns about the age of the model and some of the
limitation I believe the 2007 results are still valid. If they would like to expand to 5 MGD or more, however, we might
need to sit down with the NPDES folks to discuss the request and recommend un updated model. I have looked at the
ambient data at a couple of Rocky River stations and the DO levels are above 5 mg/l. I hope this helps. Let me know is if
you still want to meet and discuss.
Thanks.
Adugna
From: Belnick, Tom
Sent: Monday, November 16, 2015 4:23 PM
To: Behm, Pamela <[e-mail]>
Cc: Rodriguez, Teresa <[e-mail]>
Subject: WSACC Muddy Creek Spec NC0081621
Pam:
Just received a spec limits request (attached) and will need your input after you digest this material.
The Muddy Creek WWTP is currently permitted for 0.15/0.30 MGD. We issued a previous 2007 spec (attached) for
1.0/2.0/5.0 MGD, based on your run of the Rocky River QUAL2E model. The 2015 spec request is now scaled down to
0.5/1.0 MGD. You stated some concerns with the QUAL2E model used for this area, so I'd like to regroup and discuss if
the 2007 specs are still valid, or should we make the Permittee conduct additional modeling.
The 2015 request included updated USGS flow statistics, which are quite different from flows used in 1992 Level B
modeling; however, much of this can be attributed to significant differences in calculated drainage areas (553 sq miles vs
384 sq miles).
Tom Belnick
Supervisor
NPDES Complex Permitting Unit, DWR
North Carolina Department of Environmental Quality
919-807-6390 office
tom. belnick(a)-ncdenr.gov
512 North Salisbury Street

Facility: Anywhere USA
NC00
Prepared By: Tom Belnick
NCM81Q, W_N(_C114k14a
Spec- cG,..(pd�f674)/ O.J
IWC Calculations
geaL
Enter Design Flow (MGD): 0.5
Enter s7Q10 (cfs): 21
Enter w7Q10 (cfs): 21
Total Residual Chlorine (TRC)
Daily Maximum Limit (ug/1)
Ammonia (Summer)
Monthly Average Limit (mg NH3-N/1)
s7Q10 (CFS)
21
s7Q10 (CFS)
21
DESIGN FLOW (MGD)
0.5
DESIGN FLOW (MGD)
0.5
DESIGN FLOW (CFS)
0.775
DESIGN FLOW (CFS)
0.775
STREAM STD (UG/L)
17.0
STREAM STD (MG/L)
1.0
Upstream Bkgd (ug/1)
0
Upstream Bkgd (mg/1)
0.22
IWC (%)
3.56
IWC (%)
3.56
Allowable Conc. (ug/1)
478
Allowable Conc. (mg/1)
22.1
Ammonia (Winter)
Monthly Average Limit (mg NH3-N/1)
Fecal Coliform
w7Q10 (CFS)
21
Monthly Average Limit:
200/100ml DESIGN FLOW (MGD)
0.5
(If DF >331; Monitor)
DESIGN FLOW (CFS)
0.775
(If DF<331; Limit)
STREAM STD (MG/L)
1.8
Dilution Factor (DF)
28.10 Upstream Bkgd (mg/1)
0.22
IWC (%)
3.56
Allowable Conc. (mg/1)
44.6
Total Residual Chlorine
1. Cap Daily Max limit at 28 ug/I to protect for acute toxicity
Ammonia (as NH3-N)
1. If Allowable Conc > 35 mg/I, Monitor Only
2. Monthly Avg limit x 3 = Weekly Avg limit (Municipals); capped at 35 mg/I
3. Monthly Avg limit x 5 = Daily Max limit (Non-Munis); capped at 35 mg/I
4. Lower treatment cap for Minor Domestics: 2 mg/I (summer) and 4 mg/I (winter)
5. Lower treatment cap for Major Municipals: 1 mg/I (year-round)
Fecal Coliform
1. Monthly Avg limit x 2 = 400/100 ml = Weekly Avg limit (Municipals) = Daily Max limit (Non -Muni)
NPDES Server/Current Versions/WLA; TB 1/16/2009

IWC Calculations
Facility: Anywhere USA
NC00
Prepared By: Tom Belnick
Enter Design Flow (MGD):
1
Enter s7Q10 (cfs):
21
Enter w7Q10 (cfs):
21
Total Residual Chlorine (TRC)
Ammonia (Summer)
Daily Maximurn Limit (ug/1)
Monthly Average Limit (mg NH3-N/1)
s7Q10 (CFS)
21 s7Q10 (CFS)
21
DESIGN FLOW (MGD)
1 DESIGN FLOW (MGD)
1
DESIGN FLOW (CFS)
1.55 DESIGN FLOW (CFS)
1.55
STREAM STD (UG/L)
17.0 STREAM STD (MG/L)
1.0
Upstream Bkgd (ug/1)
0 Upstream Bkgd (mg/1)
0.22
IWC (%)
6.87 IWC (%)
6.87
Allowable Conc. (ug/1)
247 Allowable Conc. (mg/1)
11.6
Ammonia (Winter)
Monthly Average Limit (mg NH3-N/1)
Fecal Coliform
w7Q10 (CFS)
21
Monthly Average Limit:
200/100ml DESIGN FLOW (MGD)
1
(If DF >331; Monitor)
DESIGN FLOW (CFS)
1.55
(If DF<331; Limit)
STREAM STD (MG/L)
1.8
Dilution Factor (DF)
14.55 Upstream Bkgd (mg/1)
0.22
IWC (%)
6.87
Allowable Conc. (mg/1)
23.2
Total Residual Chlorine
1. Cap Daily Max limit at 28 ug/I to protect for acute toxicity
Ammonia (as NH3-N)
1. If Allowable Conc > 35 mg/I, Monitor
Only
2. Monthly Avg limit x 3 = Weekly Avg
limit (Municipals); capped at 35 mg/I
3. Monthly Avg limit x 5 = Daily Max limit (Non-Munis); capped at 35 mg/I
4. Lower treatment cap for Minor Domestics:
2 mg/I (summer) and 4 mg/I (winter)
5. Lower treatment cap for Major Municipals:
1 mg/I (year-round)
Fecal Coliform
1. Monthly Avg limit x 2 = 400/100 ml = Weekly Avg limit (Municipals) = Daily Max limit (Non -Muni)
NPDES Server/Current Versions/WLA;
TB 1/16/2009

IWC Calculations
Facility: Anywhere USA
NC00
Prepared By: Tom Belnick
Enter Design Flow (MGD): 0.5
Enter s7Q10 (cfs): 38.7
Enter w7010 (cfs): 38.7
Total Residual Chlorine (TRC)
Daily Maximum Limit (ug/1)
Ammonia (Summer)
Monthly Average Limit (mg NH3-N/1)
s7Q10 (CFS)
38.7
s7Q10 (CFS)
38.7
DESIGN FLOW (MGD)
0.5
DESIGN FLOW (MGD)
0.5
DESIGN FLOW (CFS)
0.775
DESIGN FLOW (CFS)
0.775
STREAM STD (UG/L)
17.0
STREAM STD (MG/L)
1.0
Upstream Bkgd (ug/1)
0
Upstream Bkgd (mg/1)
0.22
IWC (%)
1.96
IWC (%)
1.96
Allowable Conc. (ug/1)
866
Allowable Conc. (mg/1)
39.9
Ammonia (Winter)
Monthly Average Limit (mg NH3-N/1)
Fecal Coliform
w7Q10 (CFS)
38.7
Monthly Average Limit:
200/100ml DESIGN FLOW (MGD)
0.5
(If DF >331; Monitor)
DESIGN FLOW (CFS)
0.775
(If DF<331; Limit)
STREAM STD (MG/L)
1.8
Dilution Factor (DF)
50.94 Upstream Bkgd (mg/1)
0.22
IWC (%)
1.96
Allowable Conc. (mg/1)
80.7
Total Residual Chlorine
1. Cap Daily Max limit at 28 ug/I to protect for acute toxicity
Ammonia (as NH3-N)
1. If Allowable Conc > 35 mg/I, Monitor Only
2. Monthly Avg limit x 3 = Weekly Avg limit (Municipals); capped at 35 mg/I
3. Monthly Avg limit x 5 = Daily Max limit (Non-Munis); capped at 35 mg/I
4. Lower treatment cap for Minor Domestics: 2 mg/I (summer) and 4 mg/I (winter)
5. Lower treatment cap for Major Municipals: 1 mg/I (year-round)
Fecal Coliform
1. Monthly Avg limit x 2 = 400/100 ml = Weekly Avg limit (Municipals) = Daily Max limit (Non -Muni)
NPDES Server/Current Versions/WLA; TB 1/16/2009

IWC Calculations
Facility: Anywhere USA
NC00
Prepared By: Tom Belnick
Enter Design Flow (MGD): 1
Enter s7Q10 (cfs): 38.7
Enter w7Q10 (cfs): 38.7
Total Residual Chlorine (TRC)
Daily Maximum Limit (ug/1)
Ammonia (Summer)
Monthly Average Limit (mg NH3-N/1)
s7Q10 (CFS)
38.7
s7Q10 (CFS)
38.7
DESIGN FLOW (MGD)
1
DESIGN FLOW (MGD)
1
DESIGN FLOW (CFS)
1.55
DESIGN FLOW (CFS)
1.55
STREAM STD (UG/L)
17.0
STREAM STD (MG/L)
1.0
Upstream Bkgd (ug/1)
0
Upstream Bkgd (mg/1)
0.22
IWC (%)
3.85
IWC (%)
3.85
Allowable Conc. (ug/1)
441
Allowable Conc. (mg/l)
20.5
Ammonia (Winter)
Monthly Average Limit (mg NH3-N/1)
Fecal Coliform
w7010 (CFS)
38.7
Monthly Average Limit:
200/100m1 DESIGN FLOW (MGD)
1
(If DF >331I Monitor)
DESIGN FLOW (CFS)
1.55
(If DF<331; Limit)
STREAM STD (MG/L)
1.8
Dilution Factor (DF)
25.97 Upstream Bkgd (mg/1)
0.22
IWC (%)
3.85
Allowable Conc. (mg/1)
41.2
Total Residual Chlorine
1. Cap Daily Max limit at 28 ug/I to protect for acute toxicity
Ammonia (as NH3-N)
1. If Allowable Conc > 35 mg/I, Monitor Only
2. Monthly Avg limit x 3 = Weekly Avg limit (Municipals); capped at 35 mg/I
3. Monthly Avg limit x 5 = Daily Max limit (Non-Munis); capped at 35 mg/I
4. Lower treatment cap for Minor Domestics: 2 mg/I (summer) and 4 mg/I (winter)
5. Lower treatment cap for Major Municipals: 1 mg/I (year-round)
Fecal Coliform
1. Monthly Avg limit x 2 = 400/100 ml = Weekly Avg limit (Municipals) = Daily Max limit (Non -Muni)
NPDES Server/Current Versions/WLA; TB 1/16/2009

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4IIIISENGINEEAS l�dA vm
November 2, 2015 1968.015 (34)
Mr. Tom Belnick
North Carolina Department of Environmental Quality
Division of Water Resources
Water Quality Permitting Section RECEIVEDID
1617 Mall Service Center ��RlDI�%R
Raleigh, North Carolina 27699 ���✓ a
Subject: Request for Speculative NPDES Permit Limits WaterQuaiq
"dater and Sewer Authority of Cabarrus County In(�Sectlo►i
Muddy Creek WWTP (NPDES Permit No. NC0081621)
Dear Mr. Belnick,
On behalf of the Water and Sewer Authority of Cabarrus County (WSACC) we request
speculative discharge limits for expansion of the Muddy Creek WWTP (NPDES Permit No.
NC0081621). The facility currently has a NPDES Permit with limits for 0.15 and 0.3 MGD.
As growth in this area continues WSACC would like to make plans for future expansion of
this facility to 0.5 MGD or 1.0 MGD. We anticipate the facility will continue to treat primarily
domestic wastewater.
We have been in correspondence with US Geological Survey regarding low flow data for
the receiving water course, Rocky River. Attached is a copy of the email correspondence
with Mr. J. Curtis Weaver, P.E. indicating that the drainage area for this location on the
Rocky River is approximately 553 square miles with an approximate annual discharge rate
of 500 cfs. The 7Q10 discharge rate is estimated to be 38.7 cfs and the 30Q2 discharge is
estimated to be 94 cfs.
We appreciate your efforts in determining speculative discharge limits for this facility so
that WSACC can continue orderly planning for wastewater service to its customers.
Should you have any questions or need any additional information from us please do not
hesitate to contact me at 704.338.4668 or via email at [e-mail].
Yours very truly,
WI ENGI E E R
Charles . Willis, Jr`..
r., .E., BCEE
Attachments
CC' Mr. Timothy R. Kiser, P.E.,
UQA9fr �A= 5S3s� m�l�
7(� /0.7I 1 .1 r I
cFi
L hA 3
C
10700 Sikes Place, Suite 115
Charlotte, North Carolina 28277
704.377.9844 / NC License F-0114

Chuck Willis
Subject: FW: Response from USGS concerning... Re: Request for low flow characteristics
From: Weaver, John [mailto:[e-mail]]
Sent: Thursday, October 29, 2015 9:40 AM
To: Chuck Willis <[e-mail]>
Cc: John Weaver <[e-mail]>
Subject: Response from USGS concerning... Re: Request for low flow characteristics
Mr. Willis,
Thank you for your patience the past several weeks as my focus was directed to field activities following the storm surge
and flooding that affected both North Carolina and South Carolina.
In response to your inquiry about the low -flow characteristics for a location on the Rocky River near Midland in
southeastern Cabarrus County, the following information is provided:
A check of the low -flow files here at the USGS South Atlantic Water Science Center (Raleigh office) indicates several
previous low -flow determinations nearby the specific point of interest on the Rocky River, as identified by the lat/long
coordinates (35 12 28 N, 80 29 30 W) you provided via email dated October 13, 2015. No USGS discharge records are
known to exist for the point of interest.
In the absence of site -specific discharge records sufficient for a low -flow analysis, estimates of low -flow characteristics at
ungaged locations are determined by assessing a range in the low -flow yields (expressed as flow per square
mile drainage area, or cfsm) at nearby sites where estimates have been determined.
For streams in Cabarrus County, low -flow characteristics published by the USGS are provided in the following reports:
(1) The first is a basin -wide report for the Rocky River basin published in 2003. It is USGS Water -Resources
Investigations Report 03-4147, "Low -Flow Characteristics and Profiles for the Rocky River in the Yadkin -Pee Dee River
Basin, North Carolina, through 2002 (Weaver and Fine, 2003). An online version of the report is available
through http://pubs.usgs.gov/wri/wri034147/. The report provides the low -flow characteristics (based on data through
2002) for continuous -record gaging stations and partial -record sites within the Rocky River basin. The report also
provides low -flow discharge profiles (7Q10, 30Q2, winter 7Q10, and 7Q2) for the Rocky River from its headwaters in
Mecklenburg County to its mouth.
(2) The second is a recently published statewide report published in March 2015. It is USGS Scientific Investigations
Report 2015-5001, "Low -flow characteristics and flow -duration statistics for selected USGS continuous -record
streamgaging stations in North Carolina through 2012" (Weaver, 2015). The report is available online
at http://pubs.usgs.gov/sir/2015/5001/. The report provides updated low -flow characteristics and flow -duration statistics
for 266 active (as of 2012 water year) and discontinued streamgages across the state where a minimum of 10 climatic
years discharge records were available for flow analyses.
A basin delineation completed for the point of interest using the USGS StreamStats application for North Carolina
(http://water usgs gov/osw/streamstats/north carolina.html) resulted in a drainage area at 553 sgmi.
As noted above, low -flow profiles were developed for the 7Q10 and 30Q2 discharges (figures 7 and 8, respectively) in the
first report. Interpolation of the profiles allows users to estimate the low -flow statistics for ungaged locations along the
Rocky River. In the second report, only low -flow characteristics for selected continuous -record streamgages in North
Carolina were updated for publication, including the downstream streamgage on the Rocky River near Norwood (station id
02126000, drainage area 1,372 sqmi). This is the only site on the Rocky River for which low -flow characteristics were

updated as part of the recent statewide update. Of note, the drainage area at the streamgage is almost 2.5 times the
drainage area at the point of interest, .
Comparison of the published 7Q10 discharges for the Norwood streamgage in the first and second reports indicates the
7Q10 increased from 45.8 cfs to 47.0 cfs, respectively, a percentage increase of about 2.6 percent. Comparison of the
published 30Q2 discharges indicates no change in value (113 cfs) between the two reports. Because of the small
percentage change in the 7Q10 discharge values and no change for the 30Q2 discharge, it appears reasonable and
appropriate to consider the low -flow profiles in the first report as still being applicable for determining low -flow
characteristics at ungaged locations along the Rocky River.
Using interpolation between discharge values used to develop the profile, the 7Q10 and 30Q2 low -flow yields at the point
of interest are approximately 0.07 cfsm and 0.17 cfsm, respectively. Applied to the drainage area at the point of interest
(553 sgmi), the 7Q10 discharge is estimated at 38.7 cfs, and the 30Q2 discharge is estimated at 94 cfs.
The flow statistics presented in the above two reports indicate the annual average discharge yields in the Rocky River
basin are more commonly in the range of 0.9 to 1.0 cfsm. When applied to the drainage area at the point of interest, the
average annual discharge is estimated between 500 and 550 cfs.
Please note the estimated flows are provided in units of cubic feet per second (cfs).
Please understand the information provided in this message is based on a preliminary assessment and considered
provisional, subject to revision pending further analyses.
Hope this information is helpful.
Thank you.
Curtis Weaver
J. Curtis Weaver, Hydrologist, PE Email. jcweaver@usgs._gov
USGS South Atlantic Water Science Center Online: http://nc.water. usgs._gov/
North Carolina - South Carolina - Georgia
3916 Sunset Ridge Road
Raleigh, NC 27607
Phone: [phone] // Fax: [phone]
On Tue, Oct 13, 2015 at 1:09 PM, Chuck Willis <[e-mail]> wrote:
Mr. Weaver
We are working for the Water and Sewer Authority of Cabarrus County (WSACC) who operates a small wastewater
treatment plant on the Rocky River near Midland (35 12 28N, 80 29 30W). WSACC is considering expansion of this
plant and will be requesting speculative limits from the NC Division of Water Resources. As part of the request DWR will
want to know more about the low flow conditions of the river, specifically the drainage area, average flow, 7Q10 and
30Q2. Can you assist in providing this information? If there is a fee associated with this please let us know and we will
remit payment promptly.
Thank you in advance for your assistance.
- Chuck
Charles A. Willis, Jr., P.E., BCEE
Willis Engineers
10700 Sikes Place, Suite 115
Charlotte, North Carolina 28277
704.377.9844 office
704.338.4668 direct
704.641.1621 cell

Chuck Willis
Subject: FW: Response from USGS concerning... Re: Request for low flow characteristics
From: Weaver, John [mailto:[e-mail])
Sent: Thursday, October 29, 2015 9:40 AM
To: Chuck Willis <[e-mail]>
Cc: John Weaver <[e-mail]>
Subject: Response from USGS concerning... Re: Request for low flow characteristics
Mr. Willis,
Thank you for your patience the past several weeks as my focus was directed to field activities following the storm surge
and flooding that affected both North Carolina and South Carolina.
In response to your inquiry about the low -flow characteristics for a location on the Rocky River near Midland in
southeastern Cabarrus County, the following information is provided:
A check of the low -flow files here at the USGS South Atlantic Water Science Center (Raleigh office) indicates several
previous low -flow determinations nearby the specific point of interest on the Rocky River, as identified by the lat/long
coordinates (35 12 28 N, 80 29 30 W) you provided via email dated October 13, 2015. No USGS discharge records are
known to exist for the point of interest.
In the absence of site -specific discharge records sufficient for a low -flow analysis, estimates of low -flow characteristics at
ungaged locations are determined by assessing a range in the low -flow yields (expressed as flow per square
mile drainage area, or cfsm) at nearby sites where estimates have been determined.
For streams in Cabarrus County, low -flow characteristics published by the USGS are provided in the following reports:
(1) The first is a basin -wide report for the Rocky River basin published in 2003. It is USGS Water -Resources
Investigations Report 03-4147, "Low -Flow Characteristics and Profiles for the Rocky River in the Yadkin -Pee Dee River
Basin, North Carolina, through 2002" (Weaver and Fine, 2003). An online version of the report is available
through http://pubs.usgs.gov/wri/wri034147/. The report provides the low -flow characteristics (based on data through
2002) for continuous -record gaging stations and partial -record sites within the Rocky River basin. The report also
provides low -flow discharge profiles (7Q10, 30Q2, winter 7Q10, and 7Q2) for the Rocky River from its headwaters in
Mecklenburg County to its mouth.
(2) The second is a recently published statewide report published in March 2015. It is USGS Scientific Investigations
Report 2015-5001, "Low -flow characteristics and flow -duration statistics for selected USGS continuous -record
streamgaging stations in North Carolina through 2012" (Weaver, 2015). The report is available online
at http://pubs.usgs.gov/sir/2015/5001/. The report provides updated low -flow characteristics and flow -duration statistics
for 266 active (as of 2012 water year) and discontinued streamgages across the state where a minimum of 10 climatic
years discharge records were available for flow analyses.
A basin delineation completed for the point of interest using the USGS StreamStats application for North Carolina
(http://water.usgs.gov/osw/streamstats/northcarolina.html) resulted in a drainage area at 553 sgmi.
As noted above, low -flow profiles were developed for the 7Q10 and 30Q2 discharges (figures 7 and 8, respectively) in the
first report. Interpolation of the profiles allows users to estimate the low -flow statistics for ungaged locations along the
Rocky River. In the second report, only low -flow characteristics for selected continuous -record streamgages in North
Carolina were updated for publication, including the downstream streamgage on the Rocky River near Norwood (station id
02126000, drainage area 1,372 sqmi). This is the only site on the Rocky River for which low -flow characteristics were

updated as part of the recent statewide update. Of note, the drainage area at the streamgage is almost 2.5 times the
drainage area at the point of interest, .
Comparison of the published 7Q10 discharges for the Norwood streamgage in the first and second reports indicates the
A 7Q10 increased from 45.8 cfs to 47.0 cfs, respectively, a percentage increase of about 2.6 percent. Comparison of the
published 30Q2 discharges indicates no change in value (113 cfs) between the two reports. Because of the small
percentage change in the 7010 discharge values and no change for the 30Q2 discharge, it appears reasonable and
appropriate to consider the low -flow profiles in the first report as still being applicable for determining low -flow
characteristics at ungaged locations along the Rocky River.
Using interpolation between discharge values used to develop the profile, the 7Q10 and 30Q2 low -flow yields at the point
of interest are approximately 0.07 cfsm and 0.17 cfsm, respectively. Applied to the drainage area at the point of interest
(553 sgmi), the 7Q10 discharge is estimated at 38.7 cfs, and the 30Q2 discharge is estimated at 94 cfs.
The flow statistics presented in the above two reports indicate the annual average discharge yields in the Rocky River
basin are more commonly in the range of 0.9 to 1.0 cfsm. When applied to the drainage area at the point of interest, the
average annual discharge is estimated between 500 and 550 cfs.
Please note the estimated flows are provided in units of cubic feet per second (cfs).
Please understand the information provided in this message is based on a preliminary assessment and considered
provisional, subject to revision pending further analyses.
Hope this information is helpful.
Thank you.
Curtis Weaver
J. Curtis Weaver, Hydrologist, PE Email: jcweaver0us_gs._gov
USGS South Atlantic Water Science Center Online: ht_tp://nc.water. usgs._gov/
North Carolina - South Carolina - Georgia
3916 Sunset Ridge Road
Raleigh, NC 27607
Phone: [phone] // Fax: [phone]
On Tue, Oct 13, 2015 at 1:09 PM, Chuck Willis <[e-mail]> wrote:
Mr. Weaver —
We are working for the Water and Sewer Authority of Cabarrus County (WSACC) who operates a small wastewater
treatment plant on the Rocky River near Midland (35 12 28N, 80 29 30W). WSACC is considering expansion of this
plant and will be requesting speculative limits from the NC Division of Water Resources. As part of the request DWR will
want to know more about the low flow conditions of the river, specifically the drainage area, average flow, 7Q10 and
30Q2. Can you assist in providing this information? If there is a fee associated with this please let us know and we will
remit payment promptly.
Thank you in advance for your assistance.
- Chuck
Charles A. Willis, Jr., P.E., BCEE
Willis Engineers
10700 Sikes Place, Suite 115
Charlotte, North Carolina 28277
704.377.9844 office
704.338.4668 direct
704, 641.1621 cell

Plevm(l rf(NCn616D
7/Zoos
Belnick, Tom
From: Belnick, Tom
Sent: Monday, July 20, 2015 12-35 PM
To: Parker, Michael; Berry, Ron
Subject: NCO081621 WSACC/Muddy Creek WWTP
Mike/Ron- just a heads up for potential future permit action. Facility already has permitted phased flow for future
expansion to 0.3 MGD, but would need ATC permit. See link below.
http://www.independenttribune.com/news/growth-minded-midland-plans-to-double-water-treatment-
capacity/article 373f248a-2c8b-11e5-a470-5fb1de4f9948.html
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