NC0020559_Historical_1999 (2)

JAMES S. HUNT JR.
,GOVERNOR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
April 15, 1999
Mr. Eric M. Williams, City Manager
City of Henderson
P. O. Box 1434
Henderson, North Carolina 27536-1434
Subject:
Mr_ Williams:_ -.
DIVISION OF WATER QUALITY
City of Henderson v
Preliminary Engineering Reports
The Construction Grants and Loan Section has completed its review of the
:ct two Preliminary Engineering Reports and has the attached comments. A revised
which incorporates responses to these comments should be submitted for our
w and approval as soon as possible.
If you have any questions concerning this matter, please contact Cecil Madden at
)715-6203.
Sincerely,
J- akQo W
T. Allen Wahab, P. E.
Assistant Chief for Engineering Branch
Facilities Evaluation Unit
Attachments
CGM/pe
cc: McKim & Creed, Tim Baldwin
Raleigh Regional Office
Allen Wahab
DMU, FEU, SBG
CONSTRUCTION GRANT! 4 LOAN9 SECTION
P.O. BOX 29579, RALEIGH, NORTH CAROLINA 27626-0579
PHONE [phone] FA% 919-715-6229
AN EQUAL OPPORTUNITY/AFFIRMATIVE ACTION EMPLOYER-50% RECYCLED/10% POET-CONHUMCRPAPER

City of Henderson
Pump Station, Interceptor, and
Collection System 1/I Reduction
Review Comments
Provide a map of the existing sewer collection and transport system to the Nut Bush
Creek WWTP. Identify the problematic sewer lines, manholes, etc. and locate them on
the town sewer map. Estimate the extraneous flow amount that occurs from these sources
and estimate a flow reduction amount from each completed rehabilitation. Specify the
diameter and length of line, type of pipe, method of each repair.
2. Typically we do not encourage the use of pipe grouting because the lifespan of the repair
has been so short.
3. A detailed itemized cost estimate, based on the chosen repair methods for each repair
location, must be provided.
4. The database and smoke testing results should be appended to this report.
A copy of the ADS flow analysis should be appended to the report.
6. Provide basis for the estimate that 70% reduction of I/I can be achieved in areas that are
repaired. Typically we would expect this number to vary with type of repair and would
expect the average to be less than 70%.
Smoke testing is considered a planning cost and is not eligible as a part of construction.
8. Closed circuit TV cost is considered a planning or design cost and is not eligible as a part
of the construction.
9. The City should have an on going I/I reduction program and should not anticipate a 2.5%
annual escalation of remaining M.
10. Provide preliminary design calculations for sizing of the pumps and motors including
design flow, system head and pump curves. These calculations should also demonstrate
that the down stream collection and treatment systems are capable of handling the flows
without overflows and permit violations.
11. Provide a map showing the proposed location of the new interceptor, and identifying the
lengths and pipe sizes. This map should also clearly identify the proximity to streams.
12. It is not clear what is intended by the paragraph at the top of page 14 of 15; however, we
do expect sewers to change slopes only at manholes, and expect pipes to be placed at
slopes that will accommodate a minimum of 2 feet per second scour velocity. If a
minimum of 2 feet per second scour velocity is not possible, the City must address how

they intend to prevent accumulation of solids in the pipe.
13. Comments 1 through 9 also apply to the preliminary engineering report that suggests only
doing sewer rehabilitation.
14. Provide a copy of the SOC in the preliminary engineering reports.
15. Provide a copy of the Nut Bush Creek NPDES permit limits pages in the preliminary
engineering reports.
16. In the environmental assessments identify any necessary mitigative measures associated
with paralleling and/or crossing streams.

City of Henderson
Pump Station, Interceptor, and Collection System 1/1 Reduction Improvements
Table of Contents
I.
Introduction.................................................................................
3
II.
Existing Data...............................................................................3
A. Description of Project........................................................
3
B. Collection of Data..............................................................
3
C. Existing Sewer System ......................................................
4
III.
Sewer System Evaluation...........................................................
5
A. Descriptions of Basins .......................................................
5
B. Flow Analysis.....................................................................
5
C. Smoke Testing..................................................................
5
D. Repair Alternatives...........................................................
6
E. Cost Estimate...................................................................
9
IV.
Potential 1/1 Reduction.................................................................9
A. Peak Day Flow Analysis ....................................................
9
B. Peak Instantaneous Flow Analysis.................................11
C. Selection of Repair Areas................................................11
V.
Pump Station Upgrade..............................................................12
VI.
Interceptor Design.....................................................................
13
VII.
Total Project Cost Summary .....................................................
14
VIII.
Conclusions..............................................................
................ 14
Figures and Maps
Figure 1 - Location Map
Figure 2.1 - Proposed Facilities (interceptor replacement)
Figure 2.2 - Proposed Facilities Red Bud Creek Collection System)
Map 1 - Pump Station Upgrade 1/1 Study Vicinity Map
Map 2 - Pump Station Upgrade 1/1 Study Project Map
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City of Henderson
Pump Station, Interceptor, and Collection System 1/1 Reduction Improvements
Introduction
Approximately one-third of the City's wastewater collection system is located in each of three
major drainage basins - Nutbush Creek, Sandy Creek, and Red Bud Creek. Both Red Bud
and Sandy Creeks' systems are collected and tributary to a major pump station. These are
each pumped into the Nutbush Basin, join in a common interceptor, and continue to the
wastewater treatment plant.
The treatment plant is permitted for 4.14 MGD. During the period of January to March 1998 it
received average daily flows of 4.0 MGD. In addition, the City has operated under Special
Order by Consent (SOC), one element of which is to eliminate wastewater overflows at the
Red Bud pump station and downstream interceptors.
Despite a recently completed pump station upgrade and completion of some inflow/infiltration
improvements, the City has experienced continued bypasses at the Red Bud pump station and
other points in the system this winter. Clearly, a more comprehensive approach and solution is
necessary.
This report outlines the efforts made to evaluate the sewer system and identify solutions to the
problem. This project will provide inflow/infiltration reduction (predominately inflow) in
subbasins located within all three basins - Red Bud, Nutbush, and Sandy Creek, expansion of
the Red Bud pump station, and installation of a new interceptor sewer to convey the increased
pump station flows to the Nutbush Wastewater Treatment Facility. The result is a plan that will
reduce the total 1/1 in the system and eliminate overflows.
Existing Data
A. Description of Project
McKim & Creed was commissioned by the City of Henderson to perform a master planning
study of their wastewater collection and treatment system. One major element was a general
evaluation of the system with respect to infiltration/inflow and projected future flows. The 1/1
evaluation program included (a) evaluate the sewer system with respect to overflow conditions
due to 1/1, (b) determine the sections of sewer that suffered from the most severe 1/1 conditions;
(c) create a plan to determine the extent of sewer leaks and defects in these areas, this may
also include the coordination and instruction of Henderson personnel on the use of smoke
testing, (d) determine the approximate cost to return the sewer system to within capacity; and
(e) determine the overall reduction in 1/1 that may be achieved by implementing these repairs.
B. Collection of Data
General
Several sources of information were used to provide data pertaining to Henderson's sewer
system. The firm of ADS Environmental previously had performed an evaluation of the flow
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City of Henderson
Pump Station, Interceptor, and Collection System 1/1 Reduction Improvements
conditions in Henderson's sewers. This flow monitoring included a determination of the
amount of inflow and infiltration in the system. The final report from ADS was used as a
source of data by McKim & Creed. In addition to the ADS report, Henderson personnel
provided certain data about the city sewer condition from maps of the sewer system and
historical records. McKim & Creed also visited the city to visually inspect sewer line and
manhole conditions.
2. ADS Report
Information in the ADS report describes the types and amounts of 1/1 in Henderson's sewer
system based exclusively on flow metering data in selected subbasins. The report also makes
recommendations as to which areas of the sewer system should be given the highest priority
when dealing with rehabilitation.
3. Sewer Maps
Henderson provided McKim & Creed with maps of the layout of sewer pipes covering the entire
sewer system. These maps also included information on the location of sewage pump stations
and the Nutbush Wastewater Treatment Plant. In addition, Henderson submitted information
to McKim & Creed concerning the size and condition of lines within the sewer system. This
information consisted of line sizes, manhole locations and connections that were not explicitly
shown on the maps.
4. Other Information Collected
Although the 1996 report by ADS is technically correct, and the field data collection in this
study was conducted on three of the highest priority subbasins in that study, recent
observations of the sewer system contradict the priority conclusions of the ADS report. Field
observations suggest that the 1/1 problem has worsened greatly in the Red Bud Basin. Peak 1/1
flows at Red Bud have reached in excess of 1,000 gpm. This may be due to complications
with recent connections to the system in the Red Bud basin. Areas within the Red Bud basin
have experienced rapid growth. The connection of these new facilities to the sewer system
has exacerbated the problem that already exists in Red Bud. Therefore, the focus of the
recommended project will target more of the Red Bud basin than the existing older data might
suggest.
C. Existing Sewer System
Size and Material
There is approximately 588,000 feet of sewer in Henderson. The majority of this sewer is
made of clay and is 8 or 10" in diameter. However, there exists in the system some pipes that
are made of polyvinyl chloride (PVC), which were installed recently as part of repairs,
replacements, or extensions that have taken place. In addition, some pipes are larger in size,
reaching up to 24" in diameter.
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City of Henderson
Pump Station, Interceptor, and Collection System 1/1 Reduction Improvements
III. Sewer System Evaluation
A. Descriptions of Basins
The final report from ADS included information on the definition of basins within the sewer
system. Each basin, consisting of approximately 15 to 20 thousand linear feet of sewer,
conveyed sewerage from its own area toward the Nutbush Wastewater Treatment Facility.
The basins were divided into three different groups depending on the direction of flow. These
groups are Sandy Creek, which carries wastewater to the Sandy Creek Lift Station; Red Bud
Creek, which carries wastewater to the Red Bud Lift Station; and Nutbush Creek, which is
directed toward the Nutbush Wastewater Treatment Facility without passing through any major
pump station.
The Sandy Creek and Red Bud Creek Lift Stations convey wastewater from their own area
over the ridge generally formed by US1 Business and Dabney Drive to gravity sewers in the
Nutbush area. Therefore, Nutbush basin 09 carries wastewater not only from its own sewers,
but also from Sandy Creek where the lift station force main ends on S. Williams Street.
Nutbush basin 11 carries wastewater from the Bed Bud lift station where Red Bud's force main
ends on Coble Blvd.
B. Flow Analysis
The sewer system was divided into approximately 40 separate subbasins. By dividing the
sewer system into basins and sub -basins, a closer look at the 1/1 conditions in each can be
made. ADS monitored the flow in the sewer outfall of each of these basins. In addition, five
(5) rain gauges were placed in different areas to determine rainfall. These flows and rain
gauges were monitored for approximately one month in the spring of 1996.
The flows from the days of monitoring that rained, or "wet" days, were compared to the flows
from days that had no rain ("dry" days). The difference between the two was considered to be
1/I. The basins were then assigned a priority, ordering them by the ratio of 1/1 to the size of the
basin. Inflow and infiltration are reported with respect to the amount of sewer pipe in the
basin. Inflow is expected to be proportional to the length of pipe and the number of
connections. Infiltration is measured with respect to the circumference of the pipe to allow the
potential for groundwater to enter. Therefore, infiltration is reported in units of gallons per day
per inch -mile of pipe.
C. Smoke Testing
ADS calculated the flow rates for the 1/1 in each basin and the areas with the highest rates
were identified as priority areas. McKim & Creed, along with Henderson, then instituted a
program of smoke testing the sewer system to determine the nature and the extent of inflow
related sewer defects. The goal of the program was to identify which areas of the system are
in need of the most repair and estimate the cost of such repairs.
Smoke testing consists of isolating an area of the sewer system and filling it with smoke to see
where the smoke exits. Each end of the tested sewer is blocked off with sand bags to allow
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City of Henderson
Pump Station, Interceptor, and Collection System 1/1 Reduction Improvements
flow to pass through but prevent smoke from exiting. A blower is placed over the center
manhole and smoke is blown into the isolated sewer. Crews look along the length of sewer to
find smoke exits. Each smoke exit is documented and a photo is taken. This information is
placed on a report where smoke exits are described in detail and a diagram of the area is
drawn detailing each smoke exit location.
C.1 Creation of Database
McKim & Creed created a database to determine the locations for each smoke test and track
the results of each test once complete. Using the database, McKim & Creed was able to
recommend which areas of the sewer be tested and determine which areas are to be tested
first. Each smoke test stretched between 2 and 5 manholes of sewer, containing
approximately 500 - 800 feet of pipe. The database selected which manholes to examine in
each test and which manhole would be the best suited to place the blower.
C.2 Setting Testing Order
Higher priority sub -basins were tested, with the intent to extrapolate the results over the entire
system. Areas 8 and 9 from the Nutbush Creek basin and area 9 from the Sandy Creek basin
were chosen for smoke testing. These areas consist of 57,000 ft of sewer pipe, which
represents approximately 9% of the total system. These areas were identified on the ADS
report as having the worst 1/1 problems.
Tests were structured to complete one basin at a time, beginning with the outermost reaches
of the system and moving down stream to the outfall. Each test site was chosen to begin
where the previous test ended. The result was a series of 121 tests, each covering between
300 and 800 feet of sewer.
C.3 Instruction
McKim & Creed provided initial instruction and guidance to Henderson personnel on the
procedures involved in smoke testing and the specific program to be implemented.
The instruction consisted of explaining the testing order to Henderson personnel, setting up
and performing a series of tests complete with diagrams and photos, and guiding Henderson's
crews through more tests to ensure consistency in reporting.
CA Testing
The tests were performed by Henderson personnel during the month of November 1998.
Once completed, the test reports from each basin were forwarded to McKim & Creed.
D. Repair Alternatives
Once the smoke tests were completed, the results of the tests were entered into the database.
Each smoke exit listed on the reports was classified into one of four categories; pipes,
cleanouts, services, and manholes, according what appeared to be the cause. In some cases,
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City of Henderson
Pump Station, Interceptor, and Collection System 1/1 Reduction Improvements
the cause of the smoke leak was noted on the field report (ie. "Open Cleanout at 513 Orange
St"). In other cases, the cause was assumed based on the location of the smoke exit in
relation to the sewer system.
The defects in each category were compiled from the database and exported to a
spreadsheet. An estimate was made for the cost to repair to each defect. An explanation of
the repair estimate for each category is detailed below. The totals for each category were
added to determine an estimate for repair to the entire system.
D.1 Services
The field reports noted in several areas that abandoned services were left open or leaking. In
case where a service has been left open, the service would have to be located and closed to
prevent inflow. For a leaking service, the service would have to be excavated and repaired. It
was assumed that each service would require a two man crew two hours of time for this task.
An estimate of $12 per hour for a repair crew person plus overhead calculates to $25 per hour.
It was also estimated that $300 of materials would be required for an average repair.
D.2 Cleanouts
In some cases, the field reports state "smoke from cleanout". It was assumed that a two man
crew would need one hour to repair the problem, if needed. Some of the leaks detected were
noted as "cleanout without top" or "open cleanout". In these cases, a cap would be needed to
replace the missing one. The repair costs were estimated using the same assumptions as for
services: $25 per hour per person and $300 of materials per repair.
D.3 Manholes
There were some instances where a manhole leak was detected. To estimate costs for repair,
prices to repair or seal the manhole were quoted per foot of manhole depth. These quotes
were obtained verbally from different vendors in the area. An average depth of 8 ft per
manhole was assumed. The two products estimated for were a cured in place fiberglass liner
and an applied grout with a sealant to protect from H2S damage. In both cases, flow in the
bottom channel would not need to be interrupted, but any drop inlets would have to be
temporarily stopped. The cured in place liner was estimated at $250 per foot of depth. This
price may vary depending on the extent of leaks in each manhole. The grout coat was
estimated at $220 per foot of depth.
DA Pipes
Where the smoke test reports indicated smoke coming from a crack in pavement or from a
catch basin, it was assumed that the leak resulted from a leak in sewer pipe.
Verbal estimates were obtained from three different vendors on four different products
pertaining to sewer pipe repair. These different methods were slip lining with HDPE, PVC
folded liner pipe, Insituform, and joint sealing with grout. When estimating these repairs,
additional costs such as reworking taps, excavation, cleaning, and inspecting the line using
closed circuit television (CCTV) may be added to the initial cost of repair. In addition, the cost
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of Henderson
Pump Station, Interceptor, and Collection System 1/1 Reduction Improvements
of re -instating taps may be added to certain repair methods. Since the number of taps in each
line is not known, it was assumed at one (1) tap per fifty (50) feet of pipe.
D.4.1 Grout
Grout repair is generally suitable only for pipes with separated joints and not for pipes with
structural defects. This type of repair will only seal around the joints between two pipes. The
distance between joints was estimated at one joint per four (4) feet of pipe length.
The process of grout repair includes testing each joint along the pipe and repairing those that
fail the test. According to the vendor that was contacted for this product, as a guide,
approximately one third of the joints fail the test and require repair.
D.4.2 Spot Repair
An estimate for spot repairs is $100 per foot of pipe. In addition to the cost per foot of repair,
other costs such as excavation/backfill, pavement/cut, cleaning, and area preparation must be
considered. An area that is sufficiently wide and long enough must be cut through the
pavement and dug to access the pipe. It was assumed that an area of 5 feet by 10 feet by 8
feet deep would be cut and filled for each repair. The cost for excavation and backfill were
estimated at $20 per cubic yard each and the cost for pavement removal and resurfacing were
estimated at $25 per square yard.
When estimating this repair, the length of broken pipe must be known. Since it is not known
was assumed to be approximately 8 feet per break in pipe. In addition, smoke tests that
revealed two separate smoke leaks were assumed to have two separate breaks in the pipe,
each being 8 feet in length.
D.4.3 HDPE
Slip Lining with HDPE pipe also includes cleaning and CCTV as well as the cost for installation
and taps. In addition to these processes, the flow through the pipe must be re-routed around
the repaired pipe during installation and the site must be excavated at one end in order to
install. Excavation and flow by-pass were estimated at $4,500 per repair. The excavation was
estimated $3,500 per pit for an 8 foot pit and one pit per repair. The flow by-pass was
estimated at $1,000 per setup and one setup per repair.
The taps must be installed from the exterior of the pipe and have been estimated at $300 per
tap plus the cost to cut and pave the tap. It was assumed that a pit of 5 feet by 10 feet by 8
feet deep would be cut for each tap. A cost of $1,171 per tap was calculated.
D.4.4 Folded PVC
Costs associated with this method are for the liner, cleaning, and taps. The liner was
estimated at $36 per linear foot for 8" pipe and $40 per linear foot for 10" pipe. Cleaning is
estimated at $3 per linear foot. In this process, taps can be reworked from within the pipe at a
cost of $75 per tap.
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City of Henderson
Pump Station, Interceptor, and Collection System 1/1 Reduction Improvements
D.4.5 Cured -in -Place
In the case of cured -in -place lining, the estimate was given as a complete price. Therefore, all
associated costs, including cleaning and CCTV, are included as part of the total estimate. The
estimate of $5 per inch of diameter per linear foot was given as a guide for calculating an
estimate.
E. Cost Estimate
The cost estimate was generated using the data from the completed smoke tests. An estimate
was generated for repairing all observed defects in the basins that were smoke tested. Each
different repair technique maybe more or less applicable depending upon the exact nature of
the defect. The most appropriate repair methodology for somewhat obscured defects cannot
be determined with complete accuracy without further detailed inspect, most often by closed
circuit TV inspection. Based upon past experience with similar systems and actual observed
effects, the cost estimate includes a representative weighted composite of several types of
appropriate repair methodologies. During design and preconstruction further inspection by
CCTV will be conducted. The construction bid will include suitable quantities of unit price items
which will be exercised based on the results of these observations.
IV. Potential Ill Reduction
The focus of this project is not only to reduce the total flow at the wastewater treatment facility,
but also to eliminate overflows at the Red Bud pump Station. Therefore, the 1/1 reduction
estimate will be broken into two parts; the peak day flow at the treatment plant (highest daily
flow during a month), and the peak instantaneous flow at Red Bud pump station. Keep in
mind that when estimating reduced flows due to 1/1 removal, the effect is not a direct
relationship. When 1/1 flows are removed from the system, some back-ups in the system are
avoided, allowing previously backed -up flow to now enter the sewer. This reduces the overall
effect of 1/1 flow reduction. However, the goal of the project is not just to reduce flow at the
treatment plant, but to avoid sewer system overflows.
A. Peak Day Flow Analysis
The data set used to calculate 1/1 were average monthly and maximum day flows from January
1995 through March of 1998. In addition to the flow monitoring, precipitation and industrial
contribution data from the same time period was used. Two values from the each month of the
data set were used in 1/1 calculations, the average of average monthly flows and the average of
monthly maximum flows. The average of average monthly flows uses the average daily flow
for a period and averages each of them. The average of monthly maximum flows uses the
highest day flow from each month and averages them.
The months of monitoring were divided into two groups, those where rain was above average
(wet months) and those where rain was below average (dry months). The average monthly
precipitation for the time period was 3.83 inches. Data for the time period was averaged
among each group. The average daily flow for the period (removing industrial contribution to
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City of Henderson
Pump Station, Interceptor, and Collection System 1/1 Reduction Improvements
eliminate the effect of industry changes) was 2.57 MGD. This compares to 2.47 for dry months
and 2.74 for wet months.
During each wet month, the maximum day flow represents the dry flow plus the total 1/1 in the
system. The average of the maximum day flows for wet periods was 5.55 MGD. By
subtracting the average monthly flow for dry months, the total 1/1 in the system is 5.55 - 2.47 =
3.08 MGD.
Inflow
Inflow is the amount of water that enters the sewer directly through a defect of some sort in the
sewer system. This can be measured as the increase in flow during a wet month. Therefore,
the difference between the highest daily flow and the average daily flow for a wet month
represents the amount of inflow that can be expected during the average wet month. The
average of maximum flows from wet months was 5.55 MGD. The average wet month flow was
2.74 MGD. Therefore, inflow was calculated as 2.81 MGD for wet months. This means that
2.81 MGD of the maximum daily flow for wet months is attributable to inflow.
Inflow is caused by defects in the sewer system, whether they be breaks in pipe, broken
services, or open cleanouts. By repairing these breaks, a significant portion of the total inflow
can be removed from the system. It is assumed that up to 70% of the total inflow can be
removed by repairing these defects. A decrease of 1.97 MGD of rain induced inflow would be
achieved. However, the project consists of testing and repairing only 22% of the total system.
Therefore, the expected 1/1 flow reduction will be 0.43 MGD. This value of rain induced inflow
stated above will be achieved at the treatment system influent.
2. Infiltration
Infiltration is the amount of water entering the sewer from groundwater flow when the water
table rises above the pipe level. Since infiltration enters the system throughout the wet month,
infiltration can be measured as the difference between the average flow for a wet month and
the average flow for a dry month. The average dry month flow was 2.47 MGD. The infiltration
is 0.27 MGD.
Since infiltration enters the sewer system through the joints between pipes, re -sealing the
joints will abate a portion of the flow. However, the best method for determining the conditions
for infiltration repair, the sewer system must be inspected using CCTV. Since the system has
not been inspected through this process, an estimate for the reduction in infiltration can not be
given. However, since infiltration enters also through some of the sewer system defects that
cause 1/1 (i.e. shallow manhole leak), making the repairs necessary to remove inflow will also
remove a small portion of the infiltration.
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of Henderson
Pump Station, Interceptor, and Collection System 1/1 Reduction Improvements
B. Peak Instantaneous Flow Analysis
Peak flows at the Red Bud pump station have reached as high as 1,500 gpm. This consists of
three parts; the peak pump rate by the Red Bud pumps, the peak rate at which the overflow
tank at Red Bud fills, and the bypass rate after the overflow tank fills. The overflow tank was
installed at Red Bud earlier in 1999 to help alleviate the overflow problems. During a rain
event in January 1999, the tank, which has a volume of 130,000 gallons, filled in 4 hours. In
addition to the fill rate, the tank also experienced a bypass rate of approximately 75 gpm, as
viewed by Henderson personnel during the bypass.
Therefore, the peak instantaneous flow rate at Red Bud is:
The peak rate at which the Red Bud pumps have operated: 1,042 gpm
Overflow tank fill rate (130,000 gal in 4 hr):
542 gpm
Additional bypass rate:
+ 75 qpm
Total Peak flow rate:
1,659 gpm
Average Daily flow (rainy days of January 1999):
- 583 qpm
Total Peak 1/1 flow
1,076 gpm
It is conceivable to remove an average 70% of the total 1/1 in a length of sewer by smoke
testing and repairing defects. Since approximately 22% of the total system (127,000/588,300).
we be repaired, the expected reduction in peak flow rate at Red Bud can be found.
Peak flow rate at Red Bud:
1,076 gpm
Percent of Red Bud system to be repaired:
33%
Percent of flow removed:
70%
Estimated total Peak reduction in flow:
251 gpm
Current base wet weather flow:
583 gpm
Post -repair initial flow:
1,408 gpm
C. Selection of Repair Areas
In order to choose which basins should be smoke tested and repaired during the project, two
sources of data were used; the flow data from the 1996 ADS study and which basins would
satisfy the SOC. Flows from the ADS study were collected during the spring of 1996. The
study provided an evaluation of the flows throughout the system at that time. However,
Henderson field crews have observed the overflow situation since that time and have come to
some different conclusions. In addition to the overflows described in the ADS study, bypasses
at the Red Bud pump station have also been observed.
Since the worst basins will have the most defects, which creates the most 1/I, repairing only the
worst basins will generate the best return on investment. Therefore, approximately half of the
sewers in Henderson will be selected for further design, inspection, and repairs. These
selected subbasins are:
Sandy Creek 00 Sandy Creek 09
Nutbush Creek 09 Nutbush Creek 05 Nutbush Creek 13
Red Bud 01 Red Bud 11 Red Bud 12 Red Bud 13
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City of Henderson
Pump Station, Interceptor, and Collection System 1/1 Reduction Improvements
The cost estimate calculates as follows:
1/1 Study:
Linear footage of sewer to be repaired: 126,600
• Smoke Testing Cost (100% system @ $0.60/10 $90,300
• CCTV Cost (1/3 system @ $3.00/If) $126,600
• Anticipated Repair Cost $1,139,000
• Total $1,355,900
Note that Nutbush 09 and Sandy Creek 09 were smoke tested as part of this study and will
not require repetition.
V. Pump Station Upgrade
The existing pump station at Red Bud is having difficulty in keeping up with the extraneous
flows due to the level of 1/1 in the Red Bud system. Even once some of the 1/1 flows have been
removed through the previously referenced repairs, the station will still need an upgrade to
convey current and projected flows.
As described in Section IV.B, the initial post -repair flow to the pump station is expected to be
approximately 1,408 gpm. Of the three major drainage basins in the City's system, Red Bud
has exhibited the fastest growth, owing largely to the proximity to interchange areas of 1-85
and the new servicing of Vance -Granville Community College. Therefore, while the overall
City system is expected to grow at a rate of approximately 3% annually, the Red Bud basin
should experience a higher growth rate projected at approximately 5% annually.
Since the amount of 1/1 should decrease relative to base dry -weather wastewater flow as new
extensions are installed (which are tighter than the existing system) it may be advisable to
utilize a separate "growth rate" for I/lannually. Therefore using a 5% annual escalation of the
base wastewater flow rate of 583 gpm, and a 2.5% annual escalation of the remaining 825
gpm of 1/1 yields a total required pumping flow rate of 2,800 gpm at the end of the 20-year
planning period.
The pump station is currently designed for 965 gpm, but has had difficulty maintaining this
output. The older magnetic drives themselves account for a 5-8% loss from synchronous
speed, dramatically reducing output, and the force main (given the low design velocity of only
2.0 fps) seems to have a tendency toward deposition of grit and grease build-up. Given the
extremely flat pump curve, this can have a dramatic effect on the pump output, which has
been as low as 800 gpm.
The existing building and structures are generally in good condition. The pumps and motors,
however, are undersized for the high flow conditions. Therefore, the impellers in the pumps
will be replaced with full 15.25 inch impellers and the motors will be replaced with new 150 hp
units. The outdated magnetic drives will be replaced with modem variable frequency drives
(VFDs). The remainder of the station, including the existing force main and generator, is
adequate and will remain in place.
%VACS_RAL%V0UWLERICAW40& 001140 R_Ad Page 12 of 15

of Henderson
Pump Station, Interceptor, and Collection System 1/1 Reduction Improvements
When making such large scale changes to a pump station, some additional items must also be
taken into consideration. First, given that the station is set up as a duplex, minimal backup or
redundancy is present, so a spare pump and motor will be made available for emergency use.
A telemetry/SCADA system must also be installed to monitor the station from a remote
location. Finally, new monitoring and controls for the wet well, equalization basin, chemical
feed system, and other mechanical systems will be installed.
The expected cost of each item mentioned in the pump station upgrade is as follows:
• Replace impeller/rotating assemblies in 2 existing 5°
5416 pumps with the full 15.25-inch impeller and
replace motors
• Replace magnetic drives with variable frequency drives
• Provide one complete shelf - spare pump/motor
combination
• Install telemetry/SCADA RTU
• Install automated monitoring
• Total Pump Station Construction
VI. Interceptor Design
$140,000
$80,000
$45,000
$15,000
+ $45,000
$325,000
As the flows are pumped from the Red Bud pump station, they are conveyed to the 18 and 24"
gravity sewers at on Coble Boulevard in Nutbush basin 11 and on to the treatment plant.
Currently many, if not all segment surcharge, and some portions of the gravity sewer overflow
during peak events. With the addition of flow due to the Red Bud pump station upgrade, the
existing sewers will not be able to properly handle flows. Therefore, an upgrade to the existing
sewers will be performed.
The current post -repair required peak flow from the Red Bud pump station is 1,408 gpm.
Therefore, this sewer must be capable of conveying this flow, whether through upgrade of the
existing sewer or installation of a parallel sewer of larger size.
When designing this sewers upgrade and installation, the overall capacity of the treatment
system must be considered. This interceptor carries flows from not only the Red Bud pump
station, but from the Nutbush and Sandy Creek basins as well. Therefore, the downstream
portion of the sewer (that carries flows after the Nutbush and Sandy Creek connections) must
be designed to carry the current and anticipated future flows at the treatment plant. The
anticipated flow at the treatment plant is 7.0 MGD (4,800 gpm) in twenty years. The
anticipated flow at the Red Bud pump station (with the expected 1/1 reduction) is 2,800 gpm in
twenty years. Each flow is assigned a peak factor of 2.5 to allow for the diurnal variation in
flow. This new interceptor, along with the existing sewer, must be capable of conveying this
future flow, beginning at 5,800 gpm on Coble Boulevard and ending at 12,000 gpm at the
treatment plant.
MCE_RABVOU�CL.ERICAL\t AOOWWIUMPER_AA Page 13 of 15

City of Henderson
Pump Station, Interceptor, and Collection System 1/1 Reduction Improvements
The new sewer will be installed at the point where the existing sewer no longer has the
capacity to carry all flows. This point is located approximately 4,500 feet from the treatment
plant. A 42" pipe, laid at the existing sewers slope, will carry between 7,000 and 14,000 gpm
when flowing half full, depending on the slope of the existing section. Rather than increase
pipe size to achieve this flow requirement at the minimum or existing slope, it is much more
economical to allow for the light surcharging required in a few of the flattest pipe segments. It
is not possible to lay the entire 4,500 feet at a uniform "average" slope due to constraints
imposed by existing ground surface and conflict elevations. However, where possible to install
the pipe at an average slope across several steeper and flatter segments. Final vertical
alignment will be based an actual field survey data during design. A 30" pipe laid at the
existing sewer slope will convey between 5,000 and 9,000 gpm depending on the slope of the
section. Therefore, the combination of repairing the existing sewer and installing the new 30"
interceptor from Radio Lane to the intersection of the Sandy Creek Interceptor and a 42"
interceptor from that point to the treatment plant will properly convey all flows without overflow
and provide for adequate capacity for the 20-year planning period.
The estimated costs for the installation of the new interceptor are as follows:
• Install new 42 inch diameter interceptor $455,000
• Install new 30 inch diameter interceptor $110,000
• Install new 30 inch diameter interceptor with 48 inch $160,000
casing across 1-85 to Radio Lane pipe junction.
• Total Interceptor Construction $725,000
VII. Total Project Cost Summary
Project Cost sommary
III Study
$1,350,000
Pump Station Upgrade
$325,000
Interceptor Installation
$725,000
Total
$2,400,000
10% Contingency
$240,000
10%Technical Services
$240,000
5% Administrative and Legal Services
$120,000
Project Total
$3,000,000
Vill. Conclusions
There exists in Henderson an amount of Infiltration and Inflow (1/1) that causes excessive flow
and/or overflows in the sewer system during wet weather events. These excessive flows are
caused by defects in the sewer system due to the system's age and condition.
Given the observations made during site visits and from the reports generated during smoke
testing, it is believed that the a large percentage of the inflow portion of the I/I can be removed
%ACE RAL\VOLT%CLERICAL%1405�OW1%2WER_AA Page 14 of 15

City of Henderson
Pump Station, Interceptor, and Collection System 1/1 Reduction Improvements
from the system by repairing system defects and resealing joints. It was assumed that 70% of
the inflow can be reduced by making repairs to the sewer system defects identified in the
smoke tests.
Since each repair method has a unique cost associated to it, the cost estimates previously
discussed generate a range of costs. The range assumes that every repair will be made using
the same method. However, each repair will contain certain conditions that will be allow one
specific repair to be more feasible. Therefore, the actual cost will be made from a combination
of each of the repair methods. It was assumed that the repairs will be spread equally among
each method.
The project will result in a reduction of 1/1 throughout the system, with special focus on the Red
Bud pump station. The expected "average peak day" flow reduction throughout the system will
be 1.10 MGD. This 1/1 reduction is the anticipated decrease in the average daily flow on the
peak day of each month. The expected flow reduction at the Red Bud pump station will be
251 gpm. This reduction is the anticipated decrease in the peak instantaneous flow to the
pump station.
The expected cost of the project will be $3,000,000. This cost will include upgrade of the
existing Red Bud pump station, installation of a new 30/42" interceptor to parallel the existing
sewer from 1-85 to the treatment plant, and repair of selected defective portions of the sewer
system.
MACE_RALWOLMLERICAL11A081 MWPER A.A Page 15 of 15

i"
JO
Project
Area
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City of flende4son
City of Henderson vM NF &CREED I Figure 1
Preliminary Engineering Report Location Map

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Proposed Facilities

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City of Henderson V
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Report
Figure 2.2
Proposed Facilities

TABLE OF CONTENTS
1. CONTACTS....................................................................................................................3
2. PROJECT DESCRIPTION..............................................................................................3
3. EXISTING ENVIRONMENT.............................................................................................4
3.1 Project Location...................................................................................................4
4. NEED FOR PROJECT....................................................................................................4
S. ENVIRONMENTAL CONSEQUENCES AND MITIGATIVE MEASURES ........................4
5.1
Land Use Changes..............................................................................................4
5.2
Wetlands and Floodplains...................................................................................4
5.3
Prime or Unique Agriculture Lands......................................................................4
5.4
Public Lands........................................................................................................4
5.5
Scenic and Recreational Areas...........................................................................5
5.6
Areas of Archaeological/Historical Value............................................................. 5
5.7
Air Quality............................................................................................................ 5
5.8
Groundwater Quality............................................................................................ 5
5.9
Solid Waste Management...................................................................................5
5.10
Nuisance Conditions............................................................................................5
a) Transportation.................................................................................................5
b) Noise.............................................................................................................. 5
c) Construction.................................................................................................... 6
5.11
Endangered/Threatened Species........................................................................6
5.12
Toxic Substances................................................................................................6
5.13
Indirect Impacts...................................................................................................6
EXHIBITS
Exhibit 1 - Location Map
Exhibit 2.1 - Proposed Facilities (interceptor replacement)
Exhibit 2.2 - Proposed Facilities (Red Bud Creek Collection System)
Exhibit 3 - National Wetlands Inventory Map
Exhibit 4 - Land Use Map
Exhibit 5 - Floodplain Map
Exhibit 6 - Soils Map
IWCE_RAUVOLIICLERICAL\I�1120�EA d. Page 2 of 6

ENVIRONMENTAL ASSESSMENT
FOR
INTERCEPTOR SEWER REPLACEMENT PROJECT
City of Henderson, North Carolina
CONTACTS
The environmental assessment for the was prepared under the State Environmental
Policy Act guidelines by:
Timothy J. Baldwin, P.E., Project Manager
McKim & Creed Engineers, P.A.
5625 Dillard Road, Building 1, Suite 117
Cary, NC 27511
[phone]
For the City of Henderson:
Eric M. Williams, City Manager
180 Beckford Drive
Henderson, North Carolina 27536
[phone]
2. PROJECT DESCRIPTION
The project involves the replacement of the existing interceptor sewer from the vicinity of
Radio Lane, near 1-85 to the Nutbush Creek Wastewater Treatment Plant influent
structure. This would entail the installation of approximately 5,000 linear feet 30-inch and
42-inch diameter interceptor sewer. It also includes rehabilitation of the wastewater
collection system in the Red Bud Creek basin.
The purpose of this report is to determine the environmental impacts of the proposed
interceptor sewer replacement.
3. EXISTING ENVIRONMENT
3.1 Project Location
The City of Henderson currently operates a system of interceptor sewers of 18 through
24-inch diameter located from the vicinity of Radio Lane, near 1-85 north to the Nutbush
Creek Wastewater Treatment Plant. The proposed project involves the replacement of
this interceptor sewer. See Exhibit 1 for a more detailed location map.
The Red Bud Creek collection system is delineated in Exhibit 2.2.
\WCE RAL\VOLI\CLERrAL\1406VM1\]tAEAd Page 3 of 6

4. NEED FOR PROJECT
Approximately one-third of the City's wastewater collection system is located in each of
the three basins - Nutbush Creek, Sandy Creek, and Red Bud Creek. Both Red Bud and
Sandy Creeks' systems are collected and tributary to a major pump station. These are
each pumped into the Nutbush Basin, join in a common interceptor, and continue to the
wastewater treatment plant.
The treatment plant is permitted for 4.14 MGD. During the period of January to March
1998 it received average daily flows of 4.0 MGD. In addition, the City has operated under
Special Order by Consent (SOC), one element of which is to eliminate wastewater
overflows at the Red Bud pump station and downstream interceptors.
Despite a recently completed pump station upgrade and completion of some
inflow/infiltration improvements, the City has experienced continued bypasses at the Red
Bud pump station and other points in the system this winter. Clearly, a more
comprehensive approach and solution is necessary.
This project will provide inflow/infiltration reduction in subbasins located within Red Bud,
Nutbush, and Sandy Creek basins, upgrade the pumping capacity at Red Bud station.
and upgrade the capacity of the common plant interceptor so as to eliminate current
overflows and preclude such occurrences in the future.
5. ENVIRONMENTAL CONSEQUENCES AND MITIGATIVE MEASURES
The following section addresses key environmental issues.
5.1 Land Use Changes
The entire project area right-of-way is owned and maintained by the City of
Henderson. Existing residential and industrial development boarders the site.
Therefore, construction of the new interceptor lines will require no change in land
use for this site, nor influence land use changes in adjacent properties. A Land
Use Map is presented in Exhibit 4.
5.2 Wetlands and Floodplains
A review at the NC Federal Emergency Management Agency has been
performed, and floodplains have been identified and delineated in the vicinity of
the project. However, based on a preliminary evaluation, no impacts are
proposed. A national wetlands inventory map is presented in Exhibit 3 and a
floodplain map of the area is presented in Exhibit 5.
5.3 Prime or Unique Agriculture Lands
As indicated on Exhibit 4 - Land Use Map, there are no prime farmlands affected
by this project.
5.4 Public Lands
No public lands will be impacted.
WCE_RAuvou{OLERICAL%1406%OW1�Ad. Page 4 of 6

5.5 Scenic and Recreational Areas
A review of the project area at the NC Department of Environmental Health and
Natural Resources, Division of Parks and Recreation has been performed, and it
has been determined that no scenic or recreational areas will be impacted.
5.6 Areas of Archaeological/Historical Value
A review of the project area at the NC Archaeology Branch/Division of Archives
has been performed, and it has been determined that no properties of
architectural, historic, or archaeological significance would be affected by the
project.
5.7 Air Quality
There will be some short-term, temporary increase in dust and in exhaust
emissions from construction equipment during the construction phase. These air
emissions are expected to be very localized and of brief duration. There are no
known topographical or meteorological conditions which hinder dispersal of air
emissions in the project area. The temporary air emissions resulting from project
construction will be mitigated by dust control procedures, such as water spraying
and sweeping, and compliance with engine emissions control regulations.
5.8 Groundwater Quality
Ground water quality will not be affected by this project. Wastewater generated at
the facility will be disposed of by connection to the existing municipal system.
5.9 Solid Waste Management
The amount of solid wastes produced from this project is minimal. All solid
wastes generated will be from construction (i.e. miscellaneous rock deposits,
scrap metal, and construction debris.) All solid waste will be disposed of in the
County Landfill or a state approved private landfill.
5.10 Nuisance Conditions
a) Transportation
The primary transportation routes for the project area are Roanoke Avenue, I-
85, and NC39. Construction vehicle traffic may increase slightly on one or
more of these routes. No traffic patterns will be modified to accommodate this
project.
b) Noise
There will be some temporary noise impacts associated with the construction
equipment in the immediate vicinity of work. These impacts are expected to be
brief and localized. Noise impacts will be regulated by limiting construction to
normal working hours and the use of typical silencing on construction
equipment and vehicles.
NdCE_R OVOLIICLERICPL1�1120EA . Page 5 of 6

c) Construction
Sediment and erosion control measures, as required by the Land Quality
Division of the NCDEHNR, will be taken during the construction phase to
minimize the erosion and siltation of nearby waters. Dust control will be
accomplished to the extent possible through water -spraying.
5.11 Endangered/Threatened Species
A review of the project area at the NC Department of Environmental Resources,
Fish and Wildlife Division has been performed, and it has been determined that no
impacts to endangered/threatened species would be affected by the project
5.12 Toxic Substances
There will be no toxic substances introduced as a result of this project. The
potential exists for very minor introduction of toxic substances resulting from the
direct construction activities such as hydraulic oils, lubricants, and fuels. This
should be mitigated through careful attention to appropriate fueling and
maintenance procedures, restriction of areas where these activities can take
place and attention to appropriate maintenance of construction vehicles.
5.13 Indirect Impacts
Vehicle traffic on local City streets leading to the project site may increase slightly.
The existing infrastructure (roadways, water, and sewer) is capable of
accommodating the increased service demand.
%WCE RAL%VOLIICLERICAL11a06W0 Ik2MAd. Page 6 of 6

J�
Project
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City of Henderson I <
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City of Henderson `v 1V1nIQM&CREED
Environmental Assessment
Figure 1
Location Map

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city of
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City of Henderson V
Environmental Assessment vMCKWCRED
Figure 2.2
Proposed Facilities

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City of Henderson
City of Henderson
Environmental Assessment
46NYM&CREED
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Figure 3
National Wetlands
Inventory Map

Exhibit 4
Land Use Map

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is none i �
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FEDERAL EMERGENCY MANAGEMENT AGENCY
3 iaoo o /ooa �000 �000 see.
a CITY OF HENDERSON, NC
c YIINCE COUNTY FLOOD INSURANCE RATE MAP AUGUST 4. 1987
�' COMMUNITY NUMBER 370367 !

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City of Henderson Figure 6
Environmental Assessment :2WcIOM&CREED Soils Map

I
'IVE
MAR 31 1999
CONSTRUCTION GRANTS i I.OTiTQS SECTION
PRELIMINARY ENGINEERING REPORT
Collection System 1/1 Reduction Improvements
CITY OF HENDERSON, NC
March 1999
prepared by:
McKim & Creed Engineers, PA
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vMCKIM&CREED

City of Henderson
Collection System 1/1 Reduction Improvements
Table of Contents.
Introduction................................................................................. 3
II. Existing Data...............................................................................3
A. Description of Project........................................................ 3
B. Collection of Data.............................................................. 3
C. Existing Sewer System......................................................4
III. Sewer System Evaluation........................................................... 5
A. Descriptions of Basins ....................................................... 5
B. Flow Analysis..................................................................... 5
C. Smoke Testing.................................................................. 5
D. Repair Alternatives............................................................ 7
E. Cost Estimates.................................................................. 9
IV. Potential 1/1 Reduction.................................................................9
A. Peak Day Flow Analysis .................................................... 9
B. Peak Instantaneous Flow Analysis.................................11
C. Selection of Repair Areas................................................11
VII. Total Project Cost Summary .....................................................12
Vill. Conclusions..............................................................................12
Figures and Maps
Figure 1 - Location Map
Map 1 - 1/1 Study Vicinity Map
Map 2 - 1/1 Study Project Map
F ZLERICAW 4O8=1 VOUIER Rd. Page 2 of 13

City of Henderson
Collection System 1/1 Reduction Improvements
Introduction
Approximately one-third of the City's wastewater collection system is located in each of three
major drainage basins - Nutbush Creek, Sandy Creek, and Red Bud Creek. Both Red Bud
and Sandy Creeks' systems are collected and tributary to a major pump station. These are
each pumped into the Nutbush Basin, join in a common interceptor, and continue to the
wastewater treatment plant.
The treatment plant is permitted for 4.14 MGD. During the period of January to March 1998 it
received average daily flows of 4.0 MGD. In addition, the City has operated under Special
Order by Consent (SOC), one element of which is to eliminate wastewater overflows at the
Red Bud pump station and downstream interceptors.
Despite a recently completed pump station upgrade and completion of some inflow/infiltration
improvements, the City has experienced continued bypasses at the Red Bud pump station and
other points in the system this winter. Clearly, a more comprehensive approach and solution is
necessary.
This report outlines the efforts made to evaluate the sewer system and identify solutions to the
problem. This project will provide inflow/infiltration reduction (predominately inflow) in
subbasins located within all three basins - Red Bud, Nutbush, and Sandy Creek. The result is
a plan that will reduce the total 1/1 in the system and eliminate overflows.
Existing Data
A. Description of Project
McKim & Creed was commissioned by the City of Henderson to perform a master planning
study of their wastewater collection and treatment system. One major element was a general
evaluation of the system with respect to infiltration/inflow and projected future flows. The 1/1
evaluation program included (a) evaluate the sewer system with respect to overflow conditions
due to 1/I; (b) determine the sections of sewer that suffered from the most severe 1/1 conditions,
(c) create a plan to determine the extent of sewer leaks and defects in these areas, this may
also include the coordination and instruction of Henderson personnel on the use of smoke
testing; (d) determine the approximate cost to return the sewer system to within capacity; and
(e) determine the overall reduction in 1/1 that may be achieved by implementing these repairs.
B. Collection of Data
General
Several sources of information were used to provide data pertaining to Henderson's sewer
system. The firm of ADS Environmental previously had performed an evaluation of the flow
conditions in Henderson's sewers. This flow monitoring included a determination of the
amount of inflow and infiltration in the system. The final report from ADS was used as a
\V.ICE_RALIVO IIQERICALII4�1\ ER_8E Page 3 of 13

City of Henderson
Collection System 1/1 Reduction Improvements
source of data by McKim & Creed. In addition to the ADS report, Henderson personnel
provided certain data about the city sewer condition from maps of the sewer system and
historical records. McKim & Creed also visited the city to visually inspect sewer line and
manhole conditions.
2. ADS Report
Information in the ADS report describes the types and amounts of 1/1 in Henderson's sewer
system based exclusively on flow metering data in selected subbasins. The report also makes
recommendations as to which areas of the sewer system should be given the highest priority
when dealing with rehabilitation.
3. Sewer Maps
Henderson provided McKim & Creed with maps of the layout of sewer pipes covering the entire
sewer system. These maps also included information on the location of sewage pump stations
and the Nutbush Wastewater Treatment Plant. In addition, Henderson submitted information
to McKim & Creed concerning the size and condition of lines within the sewer system. This
information consisted of line sizes, manhole locations and connections that were not explicitly
shown on the maps.
4. Other Information Collected
Although the 1996 report by ADS is technically correct, and the field data collection in this
study was conducted on three of the highest priority subbasins in that study, recent
observations of the sewer system contradict the priority conclusions of the ADS report. Field
observations suggest that the 1/1 problem has worsened greatly in the Red Bud Basin. Peak 1/1
flows at Red Bud have reached in excess of 1,000 gpm. This may be due to complications
with recent connections to the system in the Red Bud basin. Areas within the Red Bud basin
have experienced rapid growth. The connection of these new facilities to the sewer system
has exacerbated the problem that already exists in Red Bud. Therefore, the focus of the
recommended project will target more of the Red Bud basin than the existing older data might
suggest.
C. Existing Sewer System
Size and Material
There is approximately 588,000 feet of sewer in Henderson. The majority of this sewer is
made of clay and is 8 or 10" in diameter. However, there exists in the system some pipes that
are made of polyvinyl chloride (PVC), which were installed recently as part of repairs,
replacements, or extensions that have taken place. In addition, some pipes are larger in size,
reaching up to 24" in diameter.
\DICE_RAUVMIICLERICALX1 O 1\ ER RA Page 4 of 13

City of Henderson
Collection System 1/1 Reduction Improvements
III. Sewer System Evaluation
A. Descriptions of Basins
The final report from ADS included information on the definition of basins within the sewer
system. Each basin, consisting of approximately 15 to 20 thousand linear feet of sewer,
conveyed sewerage from its own area toward the Nutbush Wastewater Treatment Facility.
The basins were divided into three different groups depending on the direction of flow. These
groups are Sandy Creek, which carries wastewater to the Sandy Creek Lift Station; Red Bud
Creek, which carries wastewater to the Red Bud Lift Station; and Nutbush Creek, which is
directed toward the Nutbush Wastewater Treatment Facility without passing through any major
pump station.
The Sandy Creek and Red Bud Creek Lift Stations convey wastewater from their own area
over the ridge generally formed by US1 Business and Dabney Drive to gravity sewers in the
Nutbush area. Therefore, Nutbush basin 09 carries wastewater not only from its own sewers,
but also from Sandy Creek where the lift station force main ends on S. Williams Street.
Nutbush basin 11 carries wastewater from the Bed Bud lift station where Red Bud's force main
ends on Coble Blvd.
B. Flow Analysis
The sewer system was divided into approximately 40 separate subbasins. By dividing the
sewer system into basins and sub -basins, a closer look at the 1/1 conditions in each can be
made. ADS monitored the flow in the sewer outfall of each of these basins. In addition, five
(5) rain gauges were placed in different areas to determine rainfall. These flows and rain
gauges were monitored for approximately one month in the spring of 1996.
The flows from the days of monitoring that rained, or `wet" days, were compared to the flows
from days that had no rain ("dry" days). The difference between the two was considered to be
1/I. The basins were then assigned a priority, ordering them by the ratio of 1/1 to the size of the
basin. Inflow and infiltration are reported with respect to the amount of sewer pipe in the
basin. Inflow is expected to be proportional to the length of pipe and the number of
connections. Infiltration is measured with respect to the circumference of the pipe to allow the
potential for groundwater to enter. Therefore, infiltration is reported in units of gallons per day
per inch -mile of pipe.
C. Smoke Testing
ADS calculated the flow rates for the Ill in each basin and the areas with the highest rates
were identified as priority areas. McKim & Creed, along with Henderson, then instituted a
program of smoke testing the sewer system to determine the nature and the extent of inflow
related sewer defects. The goal of the program was to identify which areas of the system are
in need of the most repair and estimate the cost of such repairs.
Smoke testing consists of isolating an area of the sewer system and filling it with smoke to see
where the smoke exits. Each end of the tested sewer is blocked off with sand bags to allow
\WCE_RAL%VOLI`CLERICAL\1d0810001U"ER Bd Page 5 of 13

City of Henderson
Collection System 1/1 Reduction Improvements
flow to pass through but prevent smoke from exiting. A blower is placed over the center
manhole and smoke is blown into the isolated sewer. Crews look along the length of sewer to
find smoke exits. Each smoke exit is documented and a photo is taken. This information is
placed on a report where smoke exits are described in detail and a diagram of the area is
drawn detailing each smoke exit location.
C.1 Creation of Database
McKim & Creed created a database to determine the locations for each smoke test and track
the results of each test once complete. Using the database, McKim & Creed was able to
recommend which areas of the sewer be tested and determine which areas are to be tested
first. Each smoke test stretched between 2 and 5 manholes of sewer, containing
approximately 500 - 800 feet of pipe. The database selected which manholes to examine in
each test and which manhole would be the best suited to place the blower.
C.2 Setting Testing Order
Higher priority sub -basins were tested, with the intent to extrapolate the results over the entire
system. Areas 8 and 9 from the Nutbush Creek basin and area 9 from the Sandy Creek basin
were chosen for smoke testing. These areas consist of 57,000 ft of sewer pipe, which
represents approximately 9% of the total system. These areas were identified on the ADS
report as having the worst 1/1 problems.
Tests were structured to complete one basin at a time, beginning with the outermost reaches
of the system and moving down stream to the outfall. Each test site was chosen to begin
where the previous test ended. The result was a series of 121 tests, each covering between
300 and 800 feet of sewer.
C.3 Instruction
McKim & Creed provided initial instruction and guidance to Henderson personnel on the
procedures involved in smoke testing and the specific program to be implemented.
The instruction consisted of explaining the testing order to Henderson personnel, setting up
and performing a series of tests complete with diagrams and photos, and guiding Henderson's
crews through more tests to ensure consistency in reporting.
C.4 Testing
The tests were performed by Henderson personnel during the month of November 1998.
Once completed, the test reports from each basin were forwarded to McKim & Creed. The
most recent group of test reports was sent from Henderson to McKim & Creed on November
16, 1998.
wncE_RABVWCLEMCA01mao 1ER se. Page 6 of 13

City of Henderson
Collection System 1/1 Reduction Improvements
D. Repair Alternatives
Once the smoke tests were completed, the results of the tests were entered into the database.
Each smoke exit listed on the reports was classified into one of four categories; pipes,
cleanouts, services, and manholes, according what appeared to be the cause. In some cases,
the cause of the smoke leak was noted on the field report (ie. "Open Cleanout at 513 Orange
St"). In other cases, the cause was assumed based on the location of the smoke exit in
relation to the sewer system.
The defects in each category were compiled from the database and exported to a
spreadsheet. An estimate was made for the cost to repair to each defect. An explanation of
the repair estimate for each category is detailed below. The totals for each category were
added to determine an estimate for repair to the entire system.
D.1 Services
The field reports noted in several areas that abandoned services were left open or leaking. In
case where a service has been left open, the service would have to be located and closed to
prevent inflow. For a leaking service, the service would have to be excavated and repaired. It
was assumed that each service would require a two man crew two hours of time for this task.
An estimate of $12 per hour for a repair crew person plus overhead calculates to $25 per hour.
It was also estimated that $300 of materials would be required for an average repair.
D.2 Cleanouts
In some cases, the field reports state "smoke from cleanout". It was assumed that a two man
crew would need one hour to repair the problem, if needed. Some of the leaks detected were
noted as "cleanout without top" or "open cleanout". In these cases, a cap would be needed to
replace the missing one. The repair costs were estimated using the same assumptions as for
services: $25 per hour per person and $300 of materials per repair.
D.3 Manholes
There were some instances where a manhole leak was detected. To estimate costs for repair,
prices to repair or seal the manhole were quoted per foot of manhole depth. These quotes
were obtained verbally from different vendors in the area. An average depth of S ft per
manhole was assumed. The two products estimated for were a cured in place fiberglass liner
and an applied grout with a sealant to protect from H2S damage. In both cases, flow in the
bottom channel would not need to be interrupted, but any drop inlets would have to be
temporarily stopped. The cured in place liner was estimated at $250 per foot of depth. This
price may vary depending on the extent of leaks in each manhole. The grout coat was
estimated at $220 per foot of depth.
D.4 Pipes
Where the smoke test reports indicated smoke coming from a crack in pavement or from
catch basin, it was assumed that the leak resulted from a leak in sewer pipe.
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City of Henderson
Collection System 1/1 Reduction Improvements
Verbal estimates were obtained from three different vendors on four different products
pertaining to sewer pipe repair. These different methods were slip lining with HDPE, PVC
folded liner pipe, Insituform, and joint sealing with grout. When estimating these repairs,
additional costs such as reworking taps, excavation, cleaning, and inspecting the line using
closed circuit television (CCTV) may be added to the initial cost of repair. In addition, the cost
of re -instating taps may be added to certain repair methods. Since the number of taps in each
line is not known, it was assumed at one (1) tap per fifty (50) feet of pipe.
D.4.1 Grout
Grout repair is generally suitable only for pipes with separated joints and not for pipes with
structural defects. This type of repair will only seal around the joints between two pipes. The
distance between joints was estimated at one joint per four (4) feet of pipe length.
The process of grout repair includes testing each joint along the pipe and repairing those that
fail the test. According to the vendor that was contacted for this product, as a guide,
approximately one third of the joints fail the test and require repair.
D.4.2 Spot Repair
An estimate for spot repairs is $100 per foot of pipe. In addition to the cost per foot of repair,
other costs such as excavation/backfill, pavement/cut, cleaning, and area preparation must be
considered. An area that is sufficiently wide and long enough must be cut through the
pavement and dug to access the pipe. It was assumed that an area of 5 feet by 10 feet by 8
feet deep would be cut and filled for each repair. The cost for excavation and backfill were
estimated at $20 per cubic yard each and the cost for pavement removal and resurfacing were
estimated at $25 per square yard.
When estimating this repair, the length of broken pipe must be known. Since it is not known, it
was assumed to be approximately 8 feet per break in pipe. In addition, smoke tests that
revealed two separate smoke leaks were assumed to have two separate breaks in the pipe,
each being 8 feet in length.
fNx*MCl#]»
Slip Lining with HDPE pipe also includes cleaning and CCTV as well as the cost for installation
and taps. In addition to these processes, the flow through the pipe must be re-routed around
the repaired pipe during installation and the site must be excavated at one end in order to
install. Excavation and flow by-pass were estimated at $4,500 per repair. The excavation was
estimated $3,500 per pit for an 8 foot pit and one pit per repair. The flow by-pass was
estimated at $1,000 per setup and one setup per repair.
The taps must be installed from the exterior of the pipe and have been estimated at $300 per
tap plus the cost to cut and pave the tap. It was assumed that a pit of 5 feet by 10 feet by 8
feet deep would be cut for each tap. A cost of $1,171 per tap was calculated.
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City of Henderson
Collection System 1/1 Reduction Improvements
D.4.4 Folded PVC
Costs associated with this method are for the liner, cleaning, and taps. The liner was
estimated at $36 per linear foot for 8" pipe and $40 per linear foot for 10" pipe. Cleaning is
estimated at $3 per linear foot. In this process, taps can be reworked from within the pipe at a
cost of $75 per tap.
D.4.5 Cured -in -Place
In the case of cured -in -place, the estimate was given as a complete price. Therefore, all
associated costs, including cleaning and CCTV, are included as part of the total estimate. The
estimate of $5 per inch of diameter per linear foot was given as a guide for calculating an
estimate.
E. Cost Estimate
The cost estimate was generated using the data from the completed smoke tests. An estimate
was generated for repairing all observed defects in the basins that were smoke tested. Each
different repair technique maybe more or less applicable depending upon the exact nature of
the defect. The most appropriate repair methodology for somewhat obscured defects cannot
be determined with complete accuracy without further detailed inspect, most often by closed
circuit TV inspection. Based upon past experience with similar systems and actual observed
effects, the cost estimate includes a representative weighted composite of several types of
appropriate repair methodologies. During design and preconstruction further inspection by
CCTV will be conducted. The construction bid will include suitable quantities of unit price items
which will be exercised based on the results of these observations.
IV. Potential 1/1 Reduction
The focus of this project is not only to reduce the total flow at the wastewater treatment facility,
but also to eliminate overflows at the Red Bud pump Station. Therefore, the 1/1 reduction
estimate will be broken into two parts; the peak day flow at the treatment plant (highest daily
flow during a month), and the peak instantaneous flow at Red Bud pump station. However,
when 1/1 flows are removed from the system, some back-ups in the system are avoided,
allowing previously backed -up or bypassed flow to now enter the sewer. This slightly reduces
the overall effect of 1/1 flow reduction.
A. Peak Day Flow Analysis
The data set used to calculate 1/1 were average monthly and maximum day flows from January
1995 through March of 1998. In addition to the flow monitoring, precipitation and industrial
contribution data from the same time period was used. Two values from the each month of the
data set were used in 1/1 calculations, the average of average monthly flows and the average of
monthly maximum flows. The average of average monthly flows uses the average daily flow
for a period and averages each of them. The average of monthly maximum flows uses the
highest day flow from each month and averages them.
WCERALW00%CLERCAU14onwo 1QOz ERGa Page 9 of 13

City of Henderson
Collection System 1/1 Reduction Improvements
The months of monitoring were divided into two groups, those where rain was above average
(wet months) and those where rain was below average (dry months). The average monthly
precipitation for the time period was 3.83 inches. Data for the time period was averaged
among each group. The average daily flow for the period (removing industrial contribution to
eliminate the effect of industry changes) was 2.57 MGD. This compares to 2.47 for dry months
and 2.74 for wet months.
During each wet month, the maximum day flow represents the dry flow plus the total 1/1 in the
system. The average of the maximum day flows for wet periods was 5.55 MGD. By
subtracting the average monthly flow for dry months, the total 1/1 in the system is 5.55 - 2.47 =
3.08 MGD.
Inflow
Inflow is the amount of water that enters the sewer directly through a defect of some sort in the
sewer system. This can be measured as the increase in flow during a wet month. Therefore,
the difference between the highest daily flow and the average daily flow for a wet month
represents the amount of inflow that can be expected during the average wet month. The
average of maximum flows from wet months was 5.55 MGD. The average wet month flow was
2.74 MGD. Therefore, inflow was calculated as 2.81 MGD for wet months. This means that
2.81 MGD of the maximum daily flow for wet months is attributable to inflow.
Inflow is caused by defects in the sewer system, whether they be breaks in pipe, broken
services, or open cleanouts. By repairing these breaks, a significant portion of the total inflow
can be removed from the system. It is assumed that up to 70% of the total inflow can be
removed by repairing these defects. A decrease of 1.97 MGD of rain induced inflow would be
achieved. However, the project consists of testing and repairing only 42% of the total system.
Therefore, the expected 1/1 flow reduction will be 0.83 MGD. This value of rain induced inflow
stated above will be achieved at the treatment system influent.
2. Infiltration
Infiltration is the amount of water entering the sewer from groundwater flow when the water
table rises above the pipe level. Since infiltration enters the system throughout the wet month,
infiltration can be measured as the difference between the average flow for a wet month and
the average flow for a dry month. The average dry month flow was 2.47 MGD. The infiltration
is 0.27 MGD.
Since infiltration enters the sewer system through the joints between pipes, re -sealing the
joints will abate a portion of the flow. However, the best method for determining the conditions
for infiltration repair, the sewer system must be inspected using CCTV. Since the system has
not been inspected through this process, an estimate for the reduction in infiltration can not be
given. However, since infiltration enters also through some of the sewer system defects that
cause 1/1 (i.e. shallow manhole leak), making the repairs necessary to remove inflow will also
remove a small portion of the infiltration.
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City of Henderson
Collection System 1/1 Reduction Improvements
B. Peak Instantaneous Flow Analysis
Peak flows at the Red Bud pump station have reached as high as 1500 gpm. This consists of
three parts; the peak pump rate by the Red Bud pumps, the peak rate at which the overflow
tank at Red Bud fills, and the bypass rate after the overflow tank fills. The overflow tank was
installed at Red Bud earlier in 1999 to help alleviate the overflow problems. During a rain
event in January 1999, the tank, which has a volume of 130,000 gallons, filled in 4 hours. In
addition to the fill rate, the tank also experienced a bypass rate of approximately 75 gpm, as
viewed by Henderson personnel during the bypass.
Therefore, the peak instantaneous flow rate at Red Bud is:
The peak rate at which the Red Bud pumps have operated: 1,042 gpm
Overflow tank fill rate (130,000 gal in 4 hr): 542 gpm
Additional bypass rate: + 75 qpm
Total Peak flow rate: 1,659 gpm
Average Daily flow (rainy days of January 1999): - 583 qpm
Total Peak 1/1 flow 1,076 gpm
It is conceivable to remove an average 70% of the total 1/1 in a length of sewer by smoke
testing and repairing defects. Since approximately 42% of the total system (248,100/588,300),
will be repaired, the expected reduction in peak flow rate at Red Bud can be estimated as:
Peak flow rate at Red Bud: 1,076 gpm
Percent of Red Bud system to be repaired: 74%
Percent of flow removed: 70%
Estimated total Peak reduction in flow: 559 gpm
Current base wet weather flow: 583 gpm
Post -repair initial flow: 1,100 gpm
C. Selection of Repair Areas
In order to choose which basins should be smoke tested and repaired during the project, two
sources of data were used; the flow data from the 1996 ADS study and which basins would
satisfy the SOC. Flows from the ADS study were collected during the spring of 1996. The
study provided an evaluation of the flows throughout the system at that time. However,
Henderson field crews have observed the overflow situation since that time and have come to
some different conclusions. In addition to the overflows described in the ADS study, bypasses
at the Red Bud pump station have also been observed.
The goal of the project is to not only minimize the flow at the Nutbush Wastewater Treatment
Facility, but also to eliminate the overflows at the Red Bud pump station. This will be
accomplished by repairing defects in the sewer system to minimize 1/I. Portions of the system
will be smoke tested and the defects catalogued. Each defect will be viewed using closed
circuit television (CCTV) and a repair method chosen.
Since the worst basins will have the most defects, which creates the most 1/I, repairing only the
worst basins will generate the best return on investment. Therefore, approximately half of the
MICE_RALIVOLIICLERICAU140el000 UMPER_Bd Page 11 of 13

City of Henderson
Collection System 1/1 Reduction Improvements
sewers in Henderson will be selected for further design, inspection, and repairs. These
selected subbasins are
Sandy Creek 00 Sandy Creek 09
Nutbush Creek 06 Nutbush Creek 09 Nutbush Creek 05
Red Bud 01 Red Bud 03 Red Bud 08
Red Bud 10 Red Bud 11 Red Bud 12
V. Total Project Cost Summary
The project budget for this project scope is:
Nutbush Creek 13
Red Bud 09
Red Bud 13
Prnjeci Cyst atammary:.
Linear footage of sewer to be repaired:
248,100
• Smoke Testing Cost:
$186,000
• CCTV Cost:
$124,000
• Anticipated Repair Cost:
$2,233,000
• Total
$2,543,000
10% Contingency
$254,000
10% Technical Services
$254,000
5% Administrative & Legal Services
+ $127,000
Project Total
$3,178,000
VI. Conclusions
There exists in Henderson an amount of Infiltration and Inflow (1/1) that causes excessive flow
and/or overflows in the sewer system during wet weather events. These excessive flows are
caused by defects in the sewer system due to the system's age and condition.
Given the observations made during site visits and from the reports generated during smoke
testing, it is believed that the a large percentage of the inflow portion of the 1/1 can be removed
from the system by repairing system defects and resealing joints. It was assumed that 70% of
the inflow can be reduced by making repairs to the sewer system defects identified in the
smoke tests.
Since each repair method has a unique cost associated to it, the cost estimates previously
discussed generate a range of costs. The range assumes that every repair will be made using
the same method. However, each repair will contain certain conditions that will be allow one
specific repair to be more feasible. Therefore, the actual cost will be made from a combination
of each of the repair methods. It was assumed that the repairs will be spread equally among
each method.
\VACE_RAUVOLMLERICALtl40B100 IMPER B.d Page 12 of 13

of Henderson
1/1 Reduction Improvements
The project will result in a reduction of 1/1 throughout the system, with special focus on the Red
Bud pump station. The expected "average peak day" flow reduction throughout the system will
be 1.10 MGD. This 1/1 reduction is the anticipated decrease in the average daily flow on the
peak day of each month. The expected flow reduction at the Red Bud pump station will be
559 gpm. This reduction is the anticipated decrease in the peak instantaneous flow to the
pump station.
%WCE RALIVOLMLERIC�1406M1V01PER_RA Page 13 of 13

Project
■ Area
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•
City of HendersonJV
t
City of Henderson 4, NF QM&CREED Figure 1
Preliminary Engineering Report Location Map

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OFFICES THROUGHOUT
THE SOUTHEAST
800 • 743 • 5557
HEADQUARTERS:
243 NORTH FRONT ST.
WILMINGTON. NC 28401
TEL: [phone]
FAX: [phone]
vMCMM&CREED

!R 31 1999
CONSTRUCTION GRANTS &
LOAN SECTION
ENVIRONMENTAL ASSESSMENT
for
INFLOW/INFILTRATION REDUCTION
CITY OF HENDERSON, NC
McKIM & CREED ENGINEERS, P.A.
5625 Dillard Drive
Cary, NC 27511
Project No. 1406-0002.OR
March, 1999
%WCE_RAL\VOLI FRICAL\14081 IU1 EA_4MI,E Page 1 Of 5
vMCIOV&CREED

0
TABLE OF CONTENTS
1. CONTACTS....................................................................................................................3
2. PROJECT DESCRIPTION..............................................................................................3
3. EXISTING ENVIRONMENT............................................................................................3
3.1 Project Location...................................................................................................3
3.2 Site Characteristics..............................................................................................3
4. NEED FOR PROJECT....................................................................................................4
5. ENVIRONMENTAL CONSEQUENCES AND MITIGATIVE MEASURES
........................4
AirQuality.......................................................................................................................4
Solid Waste Management...............................................................................................5
NuisanceConditions.......................................................................................................5
a) Transportation................................................................................................5
b) Noise..............................................................................................................5
c) Construction...................................................................................................5
ToxicSubstances............................................................................................................5
EXHIBITS
Exhibit 1 - Location of Proposed Facilities (Red Bud Creek Collection System)
FICLERICAW 406o01120EA-1wdLd. Page 2 of 5

0
ENVIRONMENTAL ASSESSMENT
FOR
1/1 Reduction
City of Henderson, NC
CONTACTS
The environmental assessment for the was prepared under the State Environmental
Policy Act guidelines by:
Timothy J. Baldwin, P.E., Project Manager
McKim & Creed Engineers, P.A.
5625 Dillard Road, Building 1, Suite 117
Cary, NC 27511
[phone]
For the City of Henderson:
Eric M. Williams, City Manager
180 Beckford Drive
Henderson, North Carolina 27536
[phone]
2. PROJECT DESCRIPTION
The project involves the rehabilitation of the existing wastewater collection system in
various areas of the City of Henderson. The system consists of a total of 43,000 feet of
collection sewer and six pump stations. The rehabilitation will include manhole repairs,
manhole replacements, pipeline defect repairs, service defect repairs, and direct
connection eliminations. The project goal is to provide necessary structural repairs and
remove excessive infiltration and inflow from the system, minimizing the risk of
overflows or spills.
3. EXISTING ENVIRONMENT
3.1 Project Location
The project is located within the City of Henderson or its immediate environs.
3.2 Site Characteristics
The project work will be confined to the immediate area of the collection segment under
repair (i.e. manhole, service lateral, etc.). Most of the work will be inside the segment
itself (lining, patching, etc.) and involve no land disturbance at all. Land disturbing
actually will be confined to minimum necessary for repair/replacement of the item in
question.
MICE_ RAL\VOLI%CLERICAL114080WIW2 EA_WMI. o Page 3 of 5

4. NEED FOR PROJECT
Approximately one-third of the City's wastewater collection system is located in each of
three major drainage basins - Nutbush Creek, Sandy Creek, and Red Bud Creek. Both
Red Bud and Sandy Creeks' systems are collected and tributary to a major pump
station. These are each pumped into the Nutbush Basin, join in a common interceptor,
and continue to the wastewater treatment plant.
The treatment plant is permitted for 4.14 MGD. During the period of January to March
1998 it received average daily flows of 4.0 MGD. In addition, the City has operated
under Special Order by Consent (SOC), one element of which is to eliminate
wastewater overflows at the Red Bud pump station and downstream interceptors.
Despite a recently completed pump station upgrade and completion of some
inflow/infiltration improvements, the City has experienced continued bypasses at the
Red Bud pump station and other points in the system this winter. Clearly, a more
comprehensive approach and solution is necessary.
This project will provide inflow/infiltration reduction (predominately inflow) in subbasins
located within all three basins - Red Bud, Nutbush, and Sandy Creek.
5. ENVIRONMENTAL CONSEQUENCES AND MITIGATIVE MEASURES
Given the rehabilitative nature of the project, there should be no permanent impacts to
the SEPA list of parameters:
Land Use Changes
Wetlands
Floodplains
Prime or Unique Agriculture Lands
Public Lands
Scenic and Recreational Areas
Areas of Archaeological/Historical Value
Air Quality
Groundwater Quality
Solid Waste Management
Nuisance Conditions
Endangered/Threatened Species
Toxic Substances
Indirect Impacts
There will be short term direct impacts associated with the construction activity itself:
Air Quality
There will be some short-term, temporary increase in dust and in exhaust
emissions from construction equipment during the construction phase. These
air emissions are expected to be very localized and of brief duration. There are
\VACE_RAL\VOLICLERICAL%14�1�A_landlE Page 4 of 5

no known topographical or meteorological conditions which hinder dispersal of
air emissions in the project area. The temporary air emissions resulting from
project construction will be mitigated by dust control procedures, such as water
spraying and sweeping, and compliance with engine emissions control
regulations.
Solid Waste Management
The amount of solid wastes produced from this project is minimal. All solid
wastes generated will be from construction (i.e. miscellaneous rock deposits,
scrap metal, and construction debris.) All solid waste will be disposed of in the
Regional Landfill or a state approved private landfill.
Nuisance Conditions
a) Transportation
Construction vehicle traffic may increase slightly in the project area. No
traffic patterns will be modified to accommodate this project.
b) Noise
There will be some temporary noise impacts associated with the construction
equipment in the immediate vicinity of work. These impacts are expected to
be brief and localized. Noise impacts will be regulated by limiting
construction to normal working hours and the use of typical silencing on
construction equipment and vehicles.
c) Construction
Sediment and erosion control measures, as required by the Land Quality
Division of the NCDEHNR, will be taken during the construction phase to
minimize the erosion and siltation of nearby waters. Dust control will be
accomplished to the extent possible through water -spraying.
Toxic Substances
There will be no toxic substances introduced as a result of this project. The
potential exists for very minor introduction of toxic substances resulting from the
direct construction activities such as hydraulic oils, lubricants, and fuels. This
should be mitigated through careful attention to appropriate fueling and
maintenance procedures, restriction of areas where these activities can take
place and attention to appropriate maintenance of construction vehicles.
\VALE RAUVOUZLERCAUI�1�A_IaWl.' Page 5 of 5

'h
o
• City of
Henderson
HEED :!; <
Red Bud
Basin ,/
• Red Bud
Pump Station
City of Henderson V
Environmental Assessment ' - 1NF IM&CREED
Figure 1
Location of
Proposed Facilities

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