NC0043176_Application_20210608

Letter of Transmittal
DUNN
ui in I Date: 05/27/21
1989*2013
To: NC Division of Water Resources From: City of Dunn-Heather Adams
NPDES Compliance 8 Expedited Permit PO Box 1065
Unit 101 E. Cleveland Street
1617 Mail Service Center Dunn, NC 28334
Raleigh, NC 27699-1617
Enclosed are the following documents for the City of Dunn NC0043176:
1 . SOC Application
2. SOC Additional Information for the City of Dunn
3. SOC Application Fee of $400
Sincerely,
G - RECEIVED
Heather Adams JUN 0 7 2021
Public Utilities Director
NCDEQ/DWR/NPDES

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STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER RESOURCES
APPLICATION FOR A SPECIAL ORDER BY CONSENT (SOC)
I. PERMIT RELATED INFORMATION:
1. Applicant(corporation, individual, or other): City of Dunn S I-100 -L.L .
2. Print or Type Owner's or Signing Official's Name and Title:
William P. Elmore, Jr, Mayor
3. Facility Name (as shown on Permit): Black River WWTP
4. Owner Phone: [phone] (or)
5. Owner Email: [e-mail]
4. Application Date: 05/21/2021
5. NPDES Permit No. (if applicable): NC0043176
6. Name of the specific wastewater treatment facility(if different from 1..3. above):
II. PRE-APPLICATION MEETING:
Prior to submitting this completed application form, applicants must meet with the appropriate
regional office staff to discuss whether or not an SOC is appropriate for this situation. Please
note the date this meeting occurred and who represented the permittee:
Representative: Steven Neuschafer (City Manager), Heather Adams (Public Utilities Director),
&Michael Goliber(City Engineer from Davis Martin Powell) Date: _04/15/2021
III. ADDITIONAL FLOW OR FLOW REALLOCATION:
In accordance with NCGS 143-215.67(b), only facilities owned by a unit of government may
request additional flow.
Additional flow may be allowed under an SOC only in specific circumstances. These
circumstances may include eliminating discharges that are not compliant with an NPDES or
Non-discharge permit. These circumstances do not include failure to perform proper
maintenance of treatment systems, collection systems or disposal systems. When requesting
additional flow, the facility must include its justification and supporting documentation.

If the requested additional flow is non-domestic, the facility must be able to demonstrate the
ability to effectively treat the waste and dispose of residuals. The applicant must provide a
detailed analysis of the constituents in the proposed non-domestic wastewater.
The total domestic additional flow requested: 750,000 gallons per day.
The total non-domestic additional flow requested: 0 gallons per day.
The total additional flow(sum of the above): 750,000, gallons per day.
Please attach a detailed description or project listing of the proposed allocation for additional
flow, with an explanation of how flow quantities were estimated. Further, any additional flow
requested must be justified by a complete analysis, by the permittee, that additional flow will not
adversely impact wastewater collection/treatment facilities or surface waters.
IV. NECESSITY NARRATIVE:
Please attach a narrative providing a detailed explanation of the circumstances regarding the
necessity of the proposed SOC. Include the following issues:
• Existing and/or unavoidable future violations(s) of permit conditions or limits(s),
• The existing treatment process and any process modifications that have been made to
date to ensure optimum performance of existing facilities,
• Collection system rehabilitation work completed or scheduled (including dates),
• Coordination with industrial users regarding their discharges or pretreatment facilities.
Identify any non-compliant significant industrial users and measure(s) proposed or
already taken to bring the pretreatment facilities back into compliance. If any industrial
facilities are currently under consent agreements, please attach these agreements,
• Date and outcome of last Industrial Waste Survey,
• Whether or not the facility is acting as a regional facility receiving wastewater from other
municipalities having independent pretreatment programs.
V. CERTIFICATION:
The applicant must submit a report prepared by an independent professional with expertise in
wastewater treatment. This report must address the following:
• An evaluation of existing treatment units, operational procedures and recommendations
as to how the efficiencies of these facilities can be maximized. The person in charge of
such evaluation must sign this document.
• A certification that these facilities could not be operated in a manner that would achieve
compliance with final permit limits. The person making such determination must sign
this certification.
• The effluent limits that the facility could be expected to meet if operated at their
maximum efficiency during the term of the requested SOC (be sure to consider interim
construction phases).
• Any other actions taken to correct problems prior to requesting the SOC.
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VI. PREDICTED COMPLIANCE SCHEDULE:
The applicant must submit a detailed listing of activities along with time frames that are
necessary to bring the facility into compliance. This schedule should include milestone dates for
beginning construction, ending construction, and achieving final compliance at a minimum. In
determining the milestone dates, the following should be considered:
• Time for submitting plans, specifications and appropriate engineering reports to DWR for
review and approval.
• Occurrence of major construction activities that are likely to affect facility performance
(units out of service, diversion of flows, etc.)to include a plan of action to minimize
impacts to surface waters.
• Infiltration/Inflow work, if necessary.
• Industrial users achieving compliance with their pretreatment permits if applicable.
• Toxicity Reduction Evaluations (TRE), if necessary.
VII. FUNDING SOURCES IDENTIFICATION:
The applicant must list the sources of funds utilized to complete the work needed to bring the
facility into compliance. Possible funding sources include but are not limited to loan
commitments,bonds, letters of credit, block grants and cash reserves. The applicant must show
that the funds are available, or can be secured in time to meet the schedule outlined as part of this
application.
If funding is not available at the beginning of the SOC process,the permittee must submit a copy
of all funding applications to ensure that all efforts are being made to secure such funds.
Note: A copy of the application should be sufficient to demonstrate timeliness unless regional
office has reason to request all information associated with securing funding.
THE DIVISION OF WATER RESOURCES WILL NOT ACCEPT THIS APPLICATION
PACKAGE UNLESS ALL OF THE APPLICABLE ITEMS ARE INCLUDED WITH THE
SUBMITTAL.
Required Items:
a. One original and two copies of the completed and appropriately executed application
form, along with all required attachments.
• If the SOC is for a City / Town, the person signing the SOC must be a ranking
elected official or other duly authorized employee.
• If the SOC is for a Corporation / Company / Industry / Other, the person signing
the SOC must be a principal executive officer of at least the level of vice-
president, or his duly authorized representative.
• If the SOC is for a School District, the person signing the SOC must be the
Superintendent of Schools or other duly authorized employee.
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Note: Reference to signatory requirements in SOCs may be found in the North
Carolina Administrative Code [T15A NCAC 2H .1206(a)(3)].
b. The non-refundable Special Order by Consent (SOC) processing fee of$400.00. A
check must be made payable to The Department of Environment and Natural
Resources.
c. An evaluation report prepared by an independent consultant with expertise in
wastewater. (in triplicate)
APPLICANT'S CERTIFICATION:
(NO MODIFICATION TO THIS CERTIFICATION IS ACCEPTABLE)
I, William P. Elmore, Jr., Mayor, attest this application for a Special Order by Consent (SOC)
has been reviewed by me and is accurate and complete to the best of my knowledge. I
understand if all required parts of this application are not completed and if all required
supporting information and attachments are not included, this application package may be
returned as incomplete. (Please be advised that the return of this application does not prevent
DWR from collecting all outstanding penalties upon request). Furthermore, I attest by my
signature that I fully understand that an upfront penalty, which may satisfy as a full
settlement of outstanding violations, may be imposed. {Note: Reference to upfront penalties
in Special Orders by Consent may be found in the North Carolina Administrative Code [T15A
NCAC 2H .1206(c)(3)].}
Gt/ � Date a lu o"10 a\
.gning Offi 1�� l I
Signature o Si
aw‘ R. et more 3( ry1.2t..tior
Printed Name of Signing Official
THE COMPLETED APPLICATION PACKAGE, INCLUDING THE ORIGINAL AND TWO
COPIES OF ALL SUPPORTING INFORMATION AND MATERIALS, SHOULD BE SENT
TO THE FOLLOWING ADDRESS:
NORTH CAROLINA DIVISION OF WATER RESOURCES
POINT SOURCE BRANCH
1617 MAIL SERVICE CENTER
RALEIGH,NORTH CAROLINA 27699-1617
IF THIS APPLICATION IS FOR A NON-DISCHARGE SYSTEM, THEN SEND TO:
NORTH CAROLINA DIVISION OF WATER QUALITY
AQUIFER PROTECTION SECTION
1636 MAIL SERVICE CENTER
RALEIGH,NORTH CAROLINA 27699-1636
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ADDITIONAL INFORMATION FOR CITY OF DUNN SOC APPLICATION
PREPARER
This SOC supporting document was prepared by City Engineer, Michael Goliber, of Davis Martin Powell (DMP)
with assistance from City Staff. Mr. Goliber of DMP has been actively involved with the City wastewater system
upgrades, rehabilitations, and operations, etc. for approximately 20 years, and others with DMP have been
assisting Dunn for over 50 years.
COMPLIANCE HISTORY FOR FACILITY REQUESTING THE SOC
All collection system overflow information is contained in the North Carolina Division of Water Quality
Basinwide Information Management System Database (BIMS). DMRs for the Black River WWTP are submitted
electronically each month through NCDEQ's eDMR process.
ADDITIONAL FLOW OR REALLOCATION OF EXISTING FLOW
PERMITTED CONNECTIONS
As of the date of the enacted SOC the City requests that the Moratorium be lifted and that limited flow
increases of up to 0.75 MGD additional permitted flow be allowed during the duration of the proposed SOC.
This would allow normal growth and planned development to proceed during the planning, design and
construction of collection system rehabilitation projects that the City of Dunn has received funding for. This
collection system work is funded through USDA RD, Golden Leaf and CDBG-I funding programs and totals
approximately$5M.
The Interstate 95 widening project through Dunn also includes the replacement of sanitary sewer lines
(approximately 8,300 LF) impacted by the widening and will help with eliminating Inflow/Infiltration (I/I) from
the collection system. The City will use City Staff to CCTV and smoke test in order to continue to evaluate the
system for defects and to reduce I&I.
Due to the 1-95 Project schedule being out of the City's control, this project is not included as a requirement
for the City to complete in order to achieve compliance under the SOC. However, it is being shown in Table 3
&4 to provide a representation of the additional amount of I/I to be reduced in the system. Updates for both
the 1-95 Collection System Improvements and O&M budgeted activities and repairs will be reported in the
quarterly reports.
The City requests an initial allocation of up to 0.15 MGD of additional permitted capacity be allowed once the
SOC application is submitted for projects already in progress. The City also requests additional permitted flows
of up to 0.6 MGD as collection system rehabilitation projects are completed within the system. This request
includes projects funded by Golden Leaf, CDBG-I and USDA RD.
Project Requested Flow, MGD
Golden Leaf 0.06 MGD
CDBG 0.26 MGD
USDA 0.28 MGD
These flow requests are based on the estimated I/I removed from the City of Dunn's wastewater collection
system with the completion of each project. See Table 2 & 3 for an Estimation of Potential Inflow/Infiltration
(I/I) Reduction to show the amount of I/I removed as a result of the associated projects.
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WWTP
During the period this SOC is in effect,the City also requests the WWTP ADF effluent flow limit be increased
from 3.75 MGD to 5.50 MGD. A review of the past 3 years of DMR's from Jan 2017 through March 2021 reveal
that the permitted monthly ADF of 3.75 MGD was exceeded during the months of Dec 2018, Jan 2019, Jan
2020, Feb 2020,June 2020,Aug 2020, Dec 2020,Jan 2021, Feb 2021 and March 2021. However other effluent
parameters such as BOD, NH3-N, Fecal Coliform, and TSS concentrations have remained well below NPDES
limits during the non-compliant flow months.
The City submitted a CWSRF loan/grant application in April 2021 to upgrade the clarifiers, chlorine contact
basins, and internal process piping to accommodate higher peak flows without surcharging weirs or risk of
overtopping basins.
The SOP for peak flow events includes processing the maximum flow through the WWTP before activating the
flow equalization system.This helps to prevent or minimize overflows occurring upstream of the WWTP if the
capacity of the flow equalization tank is exceeded during longer wet-weather events. This SOP also results in
increasing the monthly ADF's through the WWTP during peak flow events. However,other effluent parameters
such as BOD, NH3-N, Fecal Coliform, and TSS concentrations have remained well below NPDES limits during
the non-compliant months identified above.
Today, most WWTP's are designed with a peak flow factor of 2.5 (9.375 MGD) or higher, however, the Dunn
WWTP was re-permitted years ago with a 2.0 peak factor. The WWTP is currently unable to treat peak flows
above 8.0 MGD due to hydraulic limitations within the WWTP and limitations of the Cape Fear Effluent
Pumping System (CFEPS)force main,which conveys all effluent flow to the Cape Fear River. Further increases
of CFEPS flow rates would create high operating pressure and excessive velocities which could result in a failure
of the 40-year old, 3-mile long force main pipe. Upgrading the 40-year old, 3-mile long Cape Fear Effluent
Force Main is estimated to cost at least$10M.This estimate does not include any necessary process upgrades
to meet imposed nutrient limits.
The City is also planning to undertake a comprehensive WWTP evaluation in FY2021-22. This study will include
a nutrient model of the Black River to determine if the discharge could be relocated to the Black River which is
adjacent to the WWTP. The study will identify process upgrades to meet anticipated capacity expansion and
discharge limits for both options, allowing the City to make an informed decision about the long-term
wastewater treatment management program.
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During the period this 5OC is in effect the City also requests to be allowed to construct an interim wet
weather discharge to the Black River. To help alleviate the immediate situation,the City requests DEQ allow
an interim wet weather outfall to the Black River, which would only be activated when flows exceed the safe
pumping capacity of the CFEPS. This would allow the City to significantly reduce the frequency and volume of
overflows from manhole BR8 and provide treatment to the I/I laden wastewater prior to discharge. This would
remain in operation until an expanded WWTP and effluent conveyance to the selected discharge location is
constructed.
EXPLANATION AS TO WHY SOC IS NEEDED
The Dunn Wastewater Collection and Transportation System consists of approximately 88 miles of sewer line
ranging in size from 8 to 30 inches in diameter. The Black River Outfall (15" — 30") was installed during the
plant expansion 201 Program during the early 1980's to eliminate three wastewater-pumping stations that
were deteriorated,had inadequate capacity and were wastewater overflow sources. The Juniper Creek Outfall
(21"—27")was installed during the early 1980's expansion program to replace the deteriorated Juniper Creek
Outfall and included the Eastside Force main to transport wastewater from the Eastside Pumping Station to
the Black River WWTP.The Northern Outfall (15"-18")was also installed to replace the deteriorated Northern
Outfall.
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In 1993,the current Eastern Outfall was installed to replace the existing then 40+year old deteriorated Eastern
Outfall.The section of the original Eastern Outfall crossing Interstate 95 was not replaced at that time, but two
line segments of the outfall that were not replaced in 1993 were slipped lined using HDPE pipe manufactured
prior to 1993. It is planned that the replacement of this 65+ year old outfall segment will be completed with
the planned widening and Interchange improvements of Interstate 95. Design is complete and the project is
anticipated to be awarded in the summer of 2021.The sewer related scope includes a total of 9,100' of gravity
sewer(8"to 18"), 14 services renewals, and 58 manholes.
Many sewer lines throughout Dunn were built between the 1920's and 1960's and were constructed of short
four-foot sections of vitrified clay pipe. The joints were constructed of cement mortar, and have deteriorated
with time. The manholes that have been located and inspected through the various system evaluations show
evidence of surcharging which reflects the flat grades of the sewer lines, infiltration of groundwater through
the deteriorated joints, and periodic line blockages due to root in-growth and sand buildup.
The problems associated with I/I are primarily related to the pre-1960's mortar jointed VC pipe that is still in
service throughout the City. Even after replacing numerous miles of collection system and outfall piping, the
I/I issue persists during extended wet weather periods. As the ground water level rises in the sandy wet soils
during extensive wet weather, I/I increases, and overflows occur. Installation of the flow equalization tank at
the WWTP and increasing the influent pumping capacity at the WWTP, along with additional improvements
have assisted to improve peak flow through the plant. During extreme wet weather conditions, flow is
maximized through the 3.75 MGD permitted WWTP in order to maximize the storage capacity of the 3 MG
WWTP flow equalization tank. Once the equalization tank is at capacity, SSO's will occur upstream of the
WWTP. Likewise, the Eastside pumping system has been expanded to 2,500 GPM capacity. The identified
collection system rehab projects certainly will assist with reducing I&I in the system and thus easing the burden
on the WWTP.
The City has made significant strides in replacing and repairing the wastewater collection system over the past
40 years. The City has invested in extensive man-hours efforts, acquired various loans and grants and spent
significant amounts of monies to evaluate, locate and rehabilitate or replace many of the significant I/I related
issues associated with the most deteriorated segments of the wastewater collection system. The commitment
shown below as well as other information described in the Actions Taken by the Applicant Section below
further substantiates these efforts.
Since 2008, the City has received two Rural Center grants totaling $800,000, a $3M CWMTF grant, a $2.5M
CWSRF loan, and spent over$3M of its fund balance to upgrade the capacity of the Eastside pumping system,
upgrade WWTP headworks pumping and screening equipment; construction of a 3 MG flow equalization
system at the WWTP, and rehabilitate or replacement of some of the most deteriorated segments of the
collection system that contributed significant I/I during wet weather events. After completing construction of
the projects,the City experienced a reduction in I/I, reducing flows at the Black River WWTP and Eastside Pump
Station during wet weather events until the more extensive wet weather rainfall events returned in late 2015
and early 2016. A decline in wet weather I/I wet weather events then began later in 2016 and primarily lasted
through 2019. Since 2019, the increase in wet weather events have been some of the highest recorded in
decades as indicated by the graph below.
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Graph 1.WWTP Average Annual Flows and Annual Rainfall Amounts
Wastewater Treatment Plant Actual Flow vs Permitted Flow
4.0 80
0 3.0 - 60
�
a 2.0 40
1.0 20 m
0.0 — -- 0
2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
Year
M®Average Daily Wastewater Flow(Million Gallons per Day)
�WWTP Capacity(Million Gallons per Day)
-Total Annual Rainfall(inches)
EXPLANATION OF ACTIONS TAKEN BY THE APPLICANT TO MAXIMIZE THE EFFICIENCY OF THE
FACILITY PRIOR TO REQUESTING THE SOC
The City has worked diligently over the past 20 years to implement improvements to the wastewater collection
and treatment facilities, as summarized below:
1. In 2003, the Dunn City Council adopted a 20-year Capital Improvement Program based on smoke
testing, manhole inspections, and CCTV inspections of the collection system. In 2010 an updated SSES
study was completed specifically focusing on the collection system components which contribute flows
to the Eastside Pumping system. This 2010 study was included in a CIP update in 2011. Since that
time, the City has undertaken additional studies including the completion of a Wastewater System
Asset Management Plan in 2020 and the adoption of an updated CIP in 2021. This history
demonstrates the City's understanding to the urgency in continuously addressing the collection system
I/I problems as well as improving and replacing components within their system.
2. In 2003, a 20-year CIP was prepared for the water and sewer system with grant funds from the Rural
Center and included approximately 32 sewer projects and 8 water projects. As part of the 2009
Wastewater Improvements nearly half of the sewer system CIP projects were implemented utilizing 2
Rural Center grants, a CWMTF grant, and a CWSRF loan. The total cost of the 2009 improvements
totaled over$9.0M.
3. In 2010 a Sewer System Evaluation Study (SSES), funded by a Rural Center grant, was conducted on
the portion of the sewer system which contribute flows to the Eastside pump system. The SSES
included smoke testing approximately 800 manholes and 29± miles of sewer mains that contribute
flows to the Eastside pumping system. The SSES identified sewer system areas that are subject to
significant I/I during wet weather rainfall events and included preparation of a GIS based map of the
sewer system. The results of the study included 45 public and 99 private plumbing defects that were
discovered during the smoke testing process. In addition, 9 areas were identified where sewer main
sections revealed the highest potential for Ill related issues and cost estimates were prepared for the
rehabilitation or replacement of these areas. City Staff repaired most of the service and plumbing
defects identified in the 2010 SSES.
4. In 2011 an update of the 2003 CIP was undertaken as a condition of a grant program, integrating the
findings of the 2010 Eastside SSES. Approximately 37 sewer projects and 12 water projects are
included in the 2011 CIP update.
5. In 2019,the City of Dunn received an Asset Inventory and Assessment grant to complete a Sewer Asset
Management Plan (AMP) and CIP Update for the City of Dunn wastewater system. The AMP was
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created to document, map and assess the condition of the assets in the City of Dunn wastewater
system. In addition,the AMP assists with prioritizing potential improvements within the system. The
AMP was finalized and adopted in November 2020 by the City of Dunn and an update to the City's CIP
was adopted in April 2021.
6. The WWTP Aeration Replacement Project was funded in 2018 by a DWI 0% Loan. The $3.OM project
readily met all of the DWI milestone dates and was completed in December 2020.
7. In August 2019,the City of Dunn received a $142,500 Hurricane Disaster Relief Grant from the Golden
Leaf Foundation to perform an I/I study as a result of suspected collection system damage caused by
Hurricane Florence. The City completed the study and has received additional funding from Golden
Leaf to perform the identified repairs. The project includes eight-line segments within the sanitary
sewer system to be repaired by a combination of CIPP, Pipe Bursting and direct Dig and Replace. The
line segments total nearly 2,700±LF. The project also includes repairing and recoating 14 SSMH's. This
project has an anticipated $313,586 project cost.
8. In 2021 the City of Dunn the received a CDBG award to improvement the sanitary sewer system. The
CDBG project will repair over 13,600 LF of 8" and 12" sanitary sewer lines and has an anticipated
$1,999,129 project cost.
9. Since late 2018,the City has been working with the USDA on the planning and funding associated with
a multi-phase collection system rehabilitation project. The Project is divided into four phases; Phase 1
PER was approved and funding was awarded to the City in March 2021. The initial Phase 1 sewer
rehabilitations will include over 9,000 LF of sanitary sewer, 42 SSMH's and 134 service connections.
This project has an anticipated $2,650,000 Project Cost.
10. NCDOT 1-95 Collection System Improvements will be completed as part of the Interstate 95 widening
project through Dunn. This project will include the replacement of approximately 8,300 LF of gravity
sewer(8" to 18"), 14 services renewals, and 58 manholes. This project has an anticipated sewer cost
of$2.6M.
11. The City will be undertaking internal smoke testing, lateral repairs and line repairs with City staff. There
repair and on-going O&M of the system will provide additional benefits to the reduction of I/I. Updates
on the City's Staff progress will be detailed in quarterly reports.
Planning efforts and implementation of the currently funded projects described above substantiates the City's
commitment to continuing to address I/I related problems throughout the collection system and at the
WWTP.
Actions and corrective measures taken for each individual overflow is on file with the State of North Carolina
Division of Water Quality or is contained in the North Carolina Division of Water Quality Basinwide Information
Management System Database (BIMS).
Based upon the efforts being undertaken as a part of this SOC and the monies,grants, loans, and other efforts
previously committed to rehabilitate and replace sections of the sewer collection system, or for pumping
capacity increase projects and flow equalization facilities added to the WWTP to reduce I/I or to process the
I/I with less overflows, the City of Dunn requests leniency in enforcement actions against the City while the
SOC is in effect.
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DocuSign Envelope ID:9B957453-C116-4E9D-AA5D-74544734C090
CITY OF DUNN REQUESTED TIME SCHEDULE TO BRING THE FACILITY INTO COMPLIANCE WITH
PERMIT CONDITIONS AND STATE REGULATIONS/STATUTES
Table 1. Collection System Rehabilitation Projects
Golden Leaf Funded Collection System Projects
Item Task Dates
Completed August 1, 2019
1. Receive approval of funding assistance from Golden Leaf. and August 11, 2020
2. Prepare Final Design Documents Completed
3 Submit for Permitting,Agency Reviews and Easement Completed
Acquisition and Receive Authorization to Construct p
4. Bid and Award Construction Contract for Golden Leaf Projects Award August 2021
180 days after issuance of
5. Complete Construction of various projects
Notice to Proceed
CDBG Funded Collection System Projects
Item Task Dates
1. Receive approval of funding assistance from CDBG Completed April 14, 2021
2. Prepare Final Design Documents 480 Days after award of
Funding
3.
Submit for Permitting, Agency Reviews and Easement 150 Days after submittal of
Acquisition and Receive Authorization to Construct Plans
180 Days after receipt of
4. Award Construction Contract for various projects Authorization to Construct,
permits and easements
5. Complete Construction of various projects 365 days after issuance of
Notice to Proceed
USDA Funded Collection System Project
Item Task Dates
1. Receive approval of funding assistance from USDA for Phase 1 Completed April 14,2021
Improvements and ESA concurrence.
2. Prepare Final Design Documents 180 Days after award of
Funding
3.
Submit for Permitting,Agency Reviews and Easement 150 Days after submittal of
Acquisition and Receive Authorization to Construct Plans
Bid and Award Construction Contract for USDA Phase 1 120 Days after receipt of
4. Authorization to Construct,
Projects
permits and easements
5. Complete Construction of various projects 330 days after issuance of
Notice to Proceed
Some of the items above may be dependent on agency reviews. The schedules shall be adjusted depending
upon the responsiveness in completing those reviews and the City of Dunn shall not be held responsible.
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IDENTIFY FUNDING SOURCES TO BE USED TO BRING THE FACILITY INTO COMPLIANCE
Funding for these projects will be pursued through different sources. The sources will include USDA RD grant
loan program, Golden Leaf and CDBG-I monies. The City has also developed a cost sharing plan with NCDOT
for the construction of the sanitary sewer improvements associated with the 1-95 Project. The City will use the
City's annual sewer budget to continue to utilize City staff to assist with I/I reduction activities as well.
ENGINEER's CERTIFICATION
Based upon Davis Martin Powell's (DMP) extensive experience with the City of Dunn Wastewater System,
Michael Goliber, PE certifies the accuracy of the information presented in the SOC application and this SOC
supporting document. Mr. Goliber also certifies that the City Staff operates the wastewater system to best of
their abilities utilizing as much flexibility as possible to contain I/I laden flows until such time the flow rate or
total volume of the I/I flows exceeds the wastewater systems capacity.
By: , Date: 05/25/2021
Michael P. Goliber, PE(DMP)
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CITY OF DUNN -ESTIMATION OF POTENTIAL INFILTRATION/INFLOW(I/I) REDUCTION
The City of Dunn sewer system is very similar to other older sewer systems installed in during the same time
period. Many of the gravity pipeline sections were constructed of Vitrified Clay Pipe (VCP) with short 2', 3',
and 4' mortar joints. The summary below of proposed construction projects are all areas with the older VCP
that experience excessive I/I during and after high groundwater wet weather rainfall events. In addition, the
estimations are based on the review of recent and past Sewer System Evaluation Studies(SSES),findings from
CCTV inspections,smoke testing,flow monitoring in specific drainage sub-basins,observations of manhole flow
depths during I/I events, 40+years of Engineering experience within the City of Dunn Sewer System and the
findings of one day of"Electro Scan, Inc.", scanning of 3,830'of the sewer system during a high ground water
period and when the scanned sewer lines were flowing nearly full.
The scanning of some 8" piping resulted in calculations of 0.1 to 0.5 gpm per joint I/I for 3 pipe segments, 0.5
to 1.0 gpm for another 3 pipe sections, 1.0 to 5 gpm for 4 pipe sections and over 5 gpm for one pipe section.
These calculations were based on Electro Scan's software that considers electric currents created by leaking
lines and groundwater pressures, etc.
In order to predict the potential I/I reductions for the three funded projects under the City's control, Golden
Leaf Foundation(GLF),Community Development Block Grant(CDBG)program and the Rural Development(RD)
Phase 1 project, plus the sewer line replacements included in the 1-95 widening project, estimations of I/I
reduction of 0.1 gpm per joint of 8" pipe, 0.2 gpm per joint of 12" pipe, and 0.3" gpm for larger pipes were
used. This is a very conservative approach and considering some pipe segments with open joints, cracked
pipes, etc. will actually experience considerably more I/I during high ground water and wet weather rainfall
events. Table 2 provides the potential reduction based on these assumptions.
Table 2. Potential I/I Reduction
NO. OF I/I PER POTENTIAL I/I
PROJECT SIZE LENGTH JOINTS JOINT REDUCTION
Golden Leaf Project 8 2,106 527 0.1 75,816
12 560 140 0.2 40,320
Total this project 116,136
CDBG Project 8 13,039 3,260 0.1 469,404
12 586 147 0.2 42,192
Total this project 511,596
Rural Development P1
Rehab 8 4,210 1,053 0.1 151,560
12 430 108 0.2 30,960
15 2,317 579 0.3 250,236
18 1,352 338 0.3 146,016
Total this project 578,772
Total of I/I Reduction Potential for the 3 Projects Currently Funded 1,206,504
Wage

tocuSign Envelope ID:9B957453-C116-4E9D-AA5D-74544734C090
I/I PER POTENTIAL I/I
PROJECT SIZE LENGTH NO. OF JOINTS JOINT REDUCTION
8 4210 1,053 0.1 151,560
NCDOT I-95 Sewer Lines 12 430 108 0.2 30,960
Replacements included in 15 2317 579 0.3 250,236
widening Project 18 1352 338 0.3 146,016
Total This Project 578,772
TOTAL ALL 4 PROJECTS 1,785,276
Knowing this I/I reduction potential is based on high groundwater wet weather rainfall events, and I/I will be
less during times when groundwater is not as high or when rainfall is not as intense an even more conservative
I/I reduction potential was considered. Table 3 provides and estimation of only 50% of the I/I estimated
reduction as predicted for each project.
Table 3. Potential I/I Reduction @ 50%
I/I reduction I/I reduction at
Project initial calculation 50%of I/I
Golden Leaf Project 116,136 58,068
CDBG Project 511,596 255,798
Rural Development
Phase 1 Rehab 578,772 289,386
Sub Total 1,206,504 603,252
Add 1-95 Project 578,772 289,386
Total All 4 Projects 1,785,276 892,638
Based on the information presented,the City of Dunn requests the I/I reduction potential associated with the
planned sewer system rehabilitations be considered when evaluating the quantity of additional sewer growth
potential that can be connected to the sewer system during the period of the SOC.
9IPage