HomeMy WebLinkAbout97-89 RESOLUTION•
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RESOLUTION NO.
97-89
A RESOLUTION AUTHORIZING PHASE II OF THE WHITE
RIVER WATERSHED SEWER STUDY TO PROCEED.
BE IT RESOLVED BY THE BOARD OF DIRECTORS OF THE CITY OF
FAYETTEVILLE, ARKANSAS:
Section 1. That the Board of Directors authorize the
McGoodwin, Williams & Yates consultants to proceed with Phase II
of the White River Watershed Sewer Study.
PASSED AND APPROVED this 17th day of October , 1989.
ATTEST:
By: Saleta
City C erk
APPROVED:
By:
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AGREEMENT FOR ENGINEERING SERVICES
SEWER SYSTEM STUDY
WHITE RIVER WATERSHED
MICROFILMED
THIS AGREEMENT, entered into this p day_in i �L , 1989,
by and between the City of Fayetteville, Arkansas,, he hereina r ferred to as
the "Owner," and the engineering firm of McGoodwin, Willis s and Yates, Inc.,
of Fayetteville, Arkansas, hereinafter referred to as the "Engineer,"
WITNESSETH THAT:
WHEREAS, the Owner has been experiencing overflows and bypasses from its
sanitary sewage collection system; and
WHEREAS, the Owner has requested proposals from qualified engineering
firms for the performance of a sewer system study to be used as a master plan
for future rehabilitation work in the city; and
WHEREAS, based on proposals received, the Engineer was deemed to be the
best qualified to perform such a study; and
WHEREAS, the Owner desires to employ the Engineer to perform this work;
NOW THEREFORE, in consideration of the mutual covenants and agreements
herein contained, the Owner and the Engineer, the parties hereto, stipulate
and agree that the Owner does hereby employ the Engineer to perform the
required engineering services as hereinafter set out and the Engineer agrees
to provide said services.
Section I. Scope of Services
The Engineer shall provide at his own expense a suitable engineering
staff to perform the necessary studies and evaluations and to report his
findings and recommendations to the Owner.
It is understood and hereby agreed that the Engineer will employ two
subcontractors on this project to assist with flow monitoring and field
investigation services. These firms are ADS Services, Inc., of Huntsville,
Alabama (flow monitoring) and Southeast Environmental Services, Inc., of
Murfreesboro, Tennessee (field investigation services).
The Sewer System Study will be completed in accordance with the "Plan of
Study" included herein as Appendix "A."
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Section II. Payment
In consideration of the performance of the foregoing services by the
Engineer, the Owner shall compensate the Engineer on the basis of lump sum
and unit prices as set out below:
Phase 1
1. Mobilization by Subconsultants (Lump Sum) $11,000
2. Installation and Calibration of Flow Monitoring
Stations (20 @ $500.00 per site) 10,000
3. Operation, Maintenance, and Data Collection of
Flow Monitoring Stations (20 at $21.00 per site
per day x 14 days)
5,880
4. Installation, Maintenance and Data Collection
of Rain Gauges (6 @ $15.00 per site x 14 days) ---- 1,260
5. Demobilization of Flow Monitoring Installations
(Lump Sum) 1,000
6. Manhole Inspection (500 @ $50.00) 25,000
7. Smoke Testing (250,000 L.F. @ 15t/ft.) 37,500
8. Dye and/or Flooding Test (50 @ $120.00) 6,000
9. Normal Line Cleaning (30,000 L.F. @ 75t/ft.) 22,500
10. Heavy Line Cleaning (1,000 L.F. @ $2.50/ft.) 2,500
11. Root Removal (1,000 L.F. @ $2.00/ft.) 2,000
12. T. V. Inspection (30,000 L.F. @ 75¢/ft.) 22,500
13. Manhole Exposure, if required (50 @ $25.00) 1,250
14. Field Engineering and Supervision (Lump Sum) $61,000
15. Engineering Review, Analysis of Data, and Report
Preparation (Lump Sum) 22,000
Subtotal Phase 1 Estimated Costs $231,390
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Phase 2
1. Mobilization by Subconsultants (Lump Sum) $ 4,000
2. Installation and Calibration of Flow Monitoring
Stations (20 @ $400.00 per site) 8,000
3. Operation, Maintenance and Data Collection of
Flow Monitoring Stations (20 @ $19.00 per site
per day x 45 days) 17,100
4. Installation, Maintenance and Data Collection
of Rain Gauges (6 @ $14.00 per site per day x 45
days)
5. Demobilization of Flow Monitoring Installations
(Lump Sum)
*6. Hydraulic Modeling of Key Lines and Interceptors
(Lump Sum)
7. Field Engineering and Supervision (Lump Sum)
3,780
1,000
42,000
19,000
8. Engineering Review, Analysis of Data, and Report
Preparation (Lump Sum) 20,000
Subtotal Phase 2 Estimated Costs $114,880
Phase 3
1. Mobilization by Subconsultants (Lump Sum) $ 2,000
2. Manhole Inspection (1,000 @ $50 00) 50,000
3. Flow Isolation Readings (500 @ $50.00) 25,000
4. Wet Weather Inspection (40 Subconsultant Crew
Hours @ $100.00/hr.) 4,000
5. Dye and Flooding Test (50 @ $120.00) 6,000
6. Smoke Testing (200,000 L.F. @ 15t) 30,000
7. Normal Line Cleaning (50,000 L.F. @ 75C/ft.) 37,500
8. Heavy Line Cleaning (1,000 L.F. @ $2.50/ft.) 2,500
9. Root Removal (1,000 L.F. @ $2.00/ft.) $ 2,000
*It is hereby agreed that for the lump sum price set out the amount
of hydraulic modeling is limited to 250,000 L.F.
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Phase 3 (Continued)
10. T. V. Inspection (50,000 L.F. @ 75¢/ft.) 37,500
11. Field Engineering and Supervision (Lump Sum) 61,000
12. Engineering Review, Analysis of Data, and Report
Preparation (Lump Sum) 36,000
Subtotal Phase 3 Estimated Costs $293,500
Total Estimated Costs $639,770
It is hereby understood and agreed that the quantities given under the
unit price items are estimates only. Payment shall be made on the basis of
actual number of units completed; consequently, the final costs may vary
considerably from those estimated.
For any additional work not included under the unit and lump sum prices
set out above, compensation to the Engineer shall be based on salary cost
times a factor of 2.3, plus reimbursable expenses.
Salary cost is defined as the cost of salaries of engineers, draftsmen,
stenographers, surveyors, clerks, laborers, etc., for time directly
chargeable to the project, plus Social Security contributions, employment
compensation insurance, payroll taxes, medical and insurance benefits, sick
leave, vacation, and holiday pay.
The reimbursable expenses for which the Engineer will be reimbursed
shall include travel expenses when traveling outside Northwest Arkansas in
connection with the project, rental expenses for special equipment needed for
completion of the work, purchase of material and other expenses directly
attributable to the project, including any work performed by subcontractors.
The Engineer shall charge the Owner for reimbursable expenses at actual cost
plus eight percent (8%).
Payment under this agreement shall be made monthly based upon unit
prices of work completed plus a pro rata share of lump sum fees based on
percentage of work completed as calculated by the Engineer and verified by
the Owner. Payment shall be made within 15 days after claim submittal by the
Engineer. If any of the work is suspended for an extended period of time or
abandoned as a result of orders from the Owner, the Engineer shall be paid
for work actually completed; payment to be based insofar as possible upon the
unit and lump sum prices established herein.
It is hereby understood and agreed that Phases 2 and 3 of the study may
be delayed. In this event, the unit and lump sum prices shown above will be
valid so long as all work contemplated is completed within 18 months. If the
Owner determines to delay the later phases of the work beyond this 18 -month
time frame, prices will be subject to renegotiation. Work under Phases 2
and 3 above will not commence until authorized by the Owner.
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Section III. Responsibilities of the Owner
In connection with the project, it is hereby agreed that the Owner,
without cost to the Engineer, will be responsible for the following:
A. Providing all available pertinent information required by the
Engineer for conduct of the study, including maps, drawings and
specifications and complete water consumption records and sewer
system records.
B. Providing water from the fire hydrant nearest the line segment
being televised or, if necessary, water and a water truck for
rainfall simulation tests (flooding) and sewer line cleaning.
C. Providing fire department and police department assistance when
necessary for public safety.
D. Providing access to the site of work with sufficient area for the
placement of personnel and equipment, including all rights of way
and points of public access. The Engineer will not be responsible
for restoration of easements during the course of normal operations
unless said damage is the result of negligence on the part of the
Engineer.
E. Providing a method of transportation and a site for disposal of
sand, debris and other material removed when the cleaning of lines
is necessary to perform the study.
F. Locating and exposing any or all manholes as required to perform
the study. This item of work will be completed prior to the
initiation of the physical survey by the Engineer.
G. Providing all local or city licenses and permits.
H. Clearing all blockages which, in the opinion of the Engineer, need
to be cleared to continue the study. Blockages, if any, will be
reported by the Engineer.
I. Removing of the device and repairing of the sewer line should the
cleaning jet or television camera become lodged due to a blockage
in the line.
J. Providing any information related to the existence of known safety
hazards in the wastewater collection system and clearing the system
of the hazards sufficiently to allow safe access by the Engineer's
personnel.
K. Cleaning debris from sewer lines and manholes when required for
flow monitoring.
L. Cutting samples and repairing ductile or cast iron pipe as required
for inspection purposes.
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M. Giving thorough consideration to all documents presented by the
Engineer and informing the Engineer of all decisions within a
reasonable time so as not to delay the work of the Engineer.
N. Giving prompt written notice to the Engineer whenever the Owner
observes or otherwise becomes aware of events which might
substantially alter the Engineer's performance under this
agreement.
Section IV. Insurance
The Engineer hereby agrees to carry the following insurance with respect
to the services he performs for the duration of this agreement:
A. Workmen's Compensation
B. Public Liability, including Automobile Liability
C. Professional Liability.
This agreement shall be binding upon the parties hereto, their partners,
heirs, successors, administrators and assigns; and neither party shall
assign, sublet or transfer his interest in this agreement without the prior
written consent of the other party hereto.
IN WITNESS WHEREOF, the Owner has caused these presents to be executed
in its behalf by its duly authorized representatives, and the said Engineer
by its duly authorized representatives, and the parties hereto have set their
hands and seals on the date heretofore set out.
Attest:
CITY OF FAYETTEVILLE, ARKANSAS
McGOODWIN, WILLIAMS AND YATES, INC.
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APPENDIX A
TO
AGREEMENT FOR ENGINEERING SERVICES
BETWEEN THE
CITY OF FAYETTEVILLE
AND
McGOODWIN, WILLIAMS AND YATES, INC.
SEWER SYSTEM STUDY
WHITE RIVER WATERSHED
PLAN OF STUDY
I. Purpose of Study. McGoodwin, Williams and Yates, Inc. with
Southeast Environmental Services, Inc. (formerly McCullough
Associates, Inc.) previously accomplished a sewer system evaluation
survey for the City of Fayetteville in 1977-1978. Portions of this
study were utilized to accomplish rehabilitation on the sanitary
sewer system in certain areas. Post -monitoring after two
rehabilitation construction projects showed some progress had been
made toward correcting the infiltration/inflow problem, but
bypassing and overflows from the system still occur during major
storm events. This Plan of Study will build upon the work that has
been accomplished to date, and with follow-up rehabilitation,
continue toward the goal of eliminating overflows and bypasses from
the sanitary sewer system in the White River Watershed.
II. General. McGoodwin, Williams and Yates, Inc. still has the
data from the original sewer study in our files, both in hard copy
and in digital form. Thus, this information can be readily reloaded
into our computer to be updated. It is planned to take full
advantage of our previous experience in the Fayetteville system and
of the existing data to provide a better product. We plan to
utilize the existing data and start the project immediately. The
three phased approach to the study is designed to minimize any
slack or down time by using each climatical season for optimum
studies as soon as each season becomes available. In order to
facilitate maximum efficiency of project coordination and
communication between the City and the study team, we understand
that the city staff will form a project coordination and review
team which could coordinate with the various departments within the
City that may be affected by the on-going study activities. A
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proposed project management organizational chart follows outlining
the key management staff. Members of the study team's field
operation coordination team are outlined by dashed boxes.
We will start the project this summer by updating and utilizing
the existing manhole and line inspection data. Only the manholes
and lines in new additions to the sewer system, plus a
representative sampling (10% +/-) of the existing data, will be
surveyed this summer. Simultaneously, flow monitors will be
installed for a two-week period this summer to obtain base flow
data to be compared to wet weather data to be obtained during this
coming fall or winter. Further, from the existing flow monitoring
data (existing report and/or permanent meters, if available),
approximately 40 percent of the sewer system would be selected for
smoke testing this summer.
This fall or winter, flow monitors will be installed as required
to obtain two or three significant wet weather events. A hydraulic
analysis, utilizing the results of the wet and dry weather
monitoring, the smoke testing conducted in the summer and the
existing data, would be accomplished. The hydraulic analysis and
a cost analysis would then be utilized to determine the proper
combination of sewer rehabilitation and/or relief sewers to
mitigate any bypassing or overflows in the system. Additional
required wet weather tasks for the sewer system study are planned
to be accomplished in the winter and spring of 1990. Existing data
from the 1977-1978 study and permanent flow monitoring will be
updated and utilized, where possible, to supplement the results of
the required wet weather field work.
The entire study will be presented to the City in hard copy and
digital form, along with all required software, such that the City
could perform future hydraulic analysis in-house and properly
record all rehabilitation or other 0 & M activities in the sanitary
sewer system. Also, as soon as data is available from any phase
of the project, it will be presented to the City so repair by
in-house forces can begin immediately and/or plans and
specifications could be prepared for phased rehabilitation.
III. Study Area. The study area is the sanitary collection system
in the White River Watershed. The system is composed of
approximately 700,000 linear feet of sewer, ranging primarily in
size from 6 to 36 inches in diameter. The study area would
generally consist of the 16 minisystems from the 1977-1978 study
that lie within the White River Watershed or flow by gravity into
that watershed. A vector diagram of the entire Fayetteville sewage
collection system delineating the White -Illinois Watershed boundary
is shown on the following page.
IV. Scope of Sewer Study. The scope of the study will be
generally divided into three phases in order to maximize
productivity during the varying climatical seasons as they occur
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PROJECT MANAGEMENT ORGANIZATION
FLOW MONITORING SERVICES
PROJECT DIRECTOR
J. GARRY WOOD
ADS SERVICES INC.
FLOW MONITORING SERVICES
TEMPORARY MONITORING DIV. MGR.
LYNNE DAVIS REYNOLDS
CITY OF FAYETTEVILLE
CITY OF FAYETTEVILLE
PROJECT OFFICER
PROJECT DIRECTOR
McGOODWIN, WILLIAMS AND YATES, INC.
L. CARL YATES. P.E.
PROJECT MANAGER
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1 McCOODWIN, WILLIAMS AND YATES, INC. I
L
r
JAMES C. ULMER, P.E.
PROJECT ENGINEER
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DATA ANALYSIS AND EVALUATION
McGOODW1N, WILLIAMS AND YATES, INC. I
LJEFFREY L. RICHARDS, P.E.
SYSTEMS ANALYST
cGOODWIN, WLLIAMS AND YATES, INC.
BRIAN L. GARTSIDE
FIELD INVESTIGATION SERVICES
PROJECT DIRECTOR
SE ENVIRONMENTAL SERVICES, INC.
ROBERT C. WYNNE, JR., P.E.
FIELD INVESTIGATION SERVICES
PROJECT MANAGER, SES, INC
JIM HARRIS, P.E.
rFLOW MONITORING SERVICES -1 r FIELD INVESTIGATION SERVICES -1
PROJECT MANAGER I I FIELD SUPT., SES, INC
DEENA R. RAMOS JAMES THORNELL
L J L J
MOUNT COMFORT L.S.
MINISYSTEM
POPLAR RD L.S.
NORTH
STREET
L.S.
MINISYSIEM
22
P
MINISYSTEM 1
12
NIM SYS
4
P
GREGG ST. L.S.
MINISYSTEM
11
MINISYSTEM
16 y
MINI SYSTEM
17
PORTER RD L.S.
FARMINGTON L.S.
MINISYSTEM
28
P
MINISYSTEM
23
P
MINISYS
8
P
MINISYSTEM
29} /
OLD WIRE RD
L.S.
MINISYSTEM
19
MINISYSTEM
13
NNIISYSIEM
2
MINISYSIEM
14
MINISYSTEM
15
MINISYSTEM
10
FAYETTEVILLE
WASTEWATER
TREATMENT
PLANT
N
...
MINISYSTEM MINISYSTEM
/41-1 T
12 w
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MINISYSTEM
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P
MINI
X202
GREENLAND
McCULLUM RD L.S.
LAKE SEOUOYAH/
BALDWIN
LEGEND
MINISYSTEM NO.
DENOTES PUMP
THIS SYSTEM IS PHYSICALLY
LOCATED WITHIN THE ILLINOIS
RIVER WATERSHED, BUT FLOWS
BY GRAVITY INTO THE WHITE
RIVER WATERSHED.
VECTOR DIAGRAM OF WASTEWATER FLOWS
FAYETTEVILLE, ARKANSAS
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beginning during the summer of 1989 when a notice to proceed is
expected to be issued. The project team will continually monitor
the progress of the study and be constantly aware and diligently
strive to mitigate any circumstances that might jeopardize the
project schedule. The following sections set out the various tasks
of each phase of the proposed study.
V. Phase 1. Phase 1 work will commence within one week of a
notice to proceed and will continue through the summer and early
fall months of 1989. The tasks accomplished will include dry
weather monitoring and a limited amount of manhole inspection,
smoke testing and TV inspection. The data from all previous
studies and work will be carefully analyzed and updated in our
computer. The White River Watershed contains ten ground water
gauges located in representative locations with the minisystems of
the 1977-78 study. These meters will be utilized to the fullest
extent possible.
A. Flow Monitoring. The flow monitoring will consist of a total
of approximately 20 identical monitors installed and
maintained for 14 days. The locations of the meters will be
approved by the City. The 14 -day flow monitoring period
during mid summer weather will be used to establish a base or
normal dry weather flow condition. This is the base line
condition by which all other flows are compared.
1. Map and Record Review. Map review with the McGoodwin,
Williams and Yates Project Engineer will be conducted by
ADS' Project Manager. Review encompasses all available
maps of the City's collection system. Additionally,
available I/I and SES reports will be studied. Any other
related information, such as maintenance records, pump
station records, package plant flow records, etc., will
also be reviewed. The purpose of these reviews is to
enable the ADS Project Manager to recommend preliminary
locations for metering and rain gauge sites.
2. Field Investigation. When the map and record review is
complete, McGoodwin, Williams and Yates will present a
list of recommended sites to the City. Upon approval of
the list, field investigation of the recommended sites
will commence. There are two primary objectives of the
field investigation. The first is verification of site
location, direction of flow, and functional relationship
to the overall system. The second objective is to
determine the suitability of the site from a hydraulic
and site access point -of -view.
ADS field personnel will descend each manhole recommended
as a monitoring location. Field reconnaissance is the
only adequate method for assuring that suitably hydraulic
configured manholes are chosen. If the site being
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investigated does not meet our hydraulic criteria for an
acceptable site, ADS' crews will investigate several
alternate upstream and downstream manholes in order to
locate a site with better hydraulics.
Site reports from each manhole selected during the field
investigation will be provided to the City prior to
installing any equipment. This gives the City the
opportunity to discuss and approve or disapprove all
recommended and alternate sites.
3 Proposed Metering Eauipment. It is planned to use ADS
Quadrascan 1500 meter. This meter has proven to be
reliable, accurate and durable in hundreds of
applications. The Quadrascan 1500 monitor consists of:
a) a solid-state computer memory bank,
b) a pressure transducer,
c) a quadredundant ultrasonic depth sensor,
d) an ultrasonic velocity sensor,
e) a quartz clock providing a real-time
synchronization, and
f) an interrogator/synchronizer to gather stored data
and to synchronize all units.
Rainfall data will be collected by means of tipping
bucket rain gauges.
4 Data Collection/Analvsis/Reporting. At the conclusion
of temporary monitoring, all raw data will be packaged
and sent, along with the calibrations, to the Data
Processing Center at ADS headquarters in Huntsville,
Alabama. In Huntsville, analysts will develop, by means
of the computer, the "Big Picture" look at what the
system is doing. After combining the calibration data,
site information and collected data, ADS Data Processing
produces final flow data results in both a tabular and
hydrograph format. ADS will also provide a decomposition
of all pertinent base and peak wet weather and dry
weather flows. Subsystems are ranked from worst to best
within the entire sewer system to isolate and identify
heavy inflow and infiltration areas.
B. Manhole Inspection. The next task of Phase 1 of the study
will be a manhole survey and inspection. The purpose of this
task is to determine the physical condition, location and
length of the sewer system, and possible sources of I/I in new
additions to the sewer system and to verify a representative
sample. Information obtained during the physical survey will
be utilized in determining rehabilitation cost and methods.
This phase will also familiarize field crews with the system,
identify covered manholes, and help verify the sewer map.
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The following data will be recorded from above ground:
- -Identify each manhole
- -Identify covered or unlocated manholes
- -Length between manholes
--Number & size of holes, if any, in manhole cover
--Draw invert and show direction of flow
--Construction materials and conditions of cover,
rings, and upper walls, steps
- -Quantify visible sources of extraneous flow
--Special problems & conditions, such as overflows,
bypasses, etc.
Next, the interior of the manhole will be inspected with the
use of a strong artificial light or reflected sunlight. The
following data will be recorded for each manhole inspected:
--Conditions of lower walls, steps, and troughs
- -Evidence of leaks and location
- -Type and depth of debris in the manhole
--Groundwater level at the manhole, if monitored
--Evidence of surcharge
Incoming and outgoing sewer lines connected to the manhole
shall be inspected, and the following information shall be
recorded:
--Length, size, type, and depth of pipe
--Root growth in pipe
- -Type and depth of deposition in pipe and
recommended cleaning method
- -Visible infiltration/inflow sources
--Structural conditions of pipe
- -Special problems and conditions in pipe
During the manhole and sewer inspection and during other
phases of this project, where required, traffic control for
the public safety shall be maintained. The disruption of
traffic shall be minimized. The instances where cleaning,
monitoring, or other activities do take place in the streets,
barricades, flashing lights, signs, etc. shall be provided.
C. Inflow Investigation. In this task of the Sewer System Study,
approximately 40 percent of the system which experiences
inflow during periods of rainfall will be selected for inflow
investigations. Rainfall simulation tests include, but are
not limited to, dye tests and smoke testing. Smoke testing
includes the simultaneous testing of mains and connections.
It is a very effective method of locating of the planned and
unplanned inlets of extraneous water into the sanitary system.
Each and every located problem will be referenced to at least
two permanent stationary points. Photographs will be taken
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of every located problem and referenced in the final computer
printout as an aid to the rehabilitation contractor. A
schematic drawing giving explicit directions for locating each
problem will be included.
A combined field survey form will be utilized on all field
work (flow isolation, physical survey, smoke testing), such
that numerous different forms are not required. All smoke
problems will be quantified by giving consideration to the
surrounding area contributing to the problem and the size and
density of the smoke encountered. A mass balance will be
undertaken based on flow monitoring results to ensure proper
quantification.
Dye testing will be performed on questionable or suspected
inflow sources in order that possible identification and
quantifications can be made.
1. Smoke Testing. Smoke testing shall be conducted at
approved locations. Functions to be performed and data
to be gathered include the following:
a. Locate sewer sections and manholes to be smoke
tested and check flow conditions.
b. Notify proper authorities of nature and time of
test.
c. Induce smoke and observe appearance of smoke coming
out of inlets and inflow sources.
d. Photograph and identify sources and other problems
and record data.
e. Prepare detailed sketch complete with measures from
the smoke source to two permanent objects.
f. Quantify potential inflow from the smoke source and
determine required rehabilitation method.
2 Dve Testing. Dye water test may be conducted to further
identify and quantify inflow sources resulting primarily
from rainfall events where smoke testing provides
inadequate or conflicting data. The City shall make
water available for this test. The test results shall
include the following information:
a. Evidence of dye water in manholes downstream from
the ponding area, stream crossing, or other
suspected sources where the dyed water is placed.
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b. Time of travel from contributing source to manhole
sampled and the concentration of the dyed water.
D. Line Cleaning. Selected sewer lines approved by the City will
be cleaned to eliminate obstructions for television inspection
in order that the existing condition of the sanitary sewers
can be fully assessed. Cleaning will be accomplished by use
of high pressure water jet cleaners. Where deposition
requires over three (3) passes with the jet cleaner, then
heavy cleaning employing numerous passes with the jet cleaner
or use of "Beeline" or "sewer scooters" will be implemented
at the price stated in the agreed price proposal. Root
removal, where necessary, will be with hydraulic cutters at
the agreed price proposed.
E. Television Inspection. In this phase, the specific location,
condition, estimated flow rate, and cost of rehabilitation for
each source of inflow defined in the selected segments will
be determined. Descriptive records of all structural defects,
service connections, abnormal conditions, and other pertinent
observations will be prepared during TV inspection. Video
tapes will be made of the entire TV inspection and will be
turned over to the City after the study is complete.
F Data Analysis. Data collected during the 1977-1978 study,
during rehabilitation and from flow monitoring and manhole
inspection, smoke testing and internal inspection during
Phase 1 will be verified, then processed and evaluated through
our computerized data processing system. The results of the
flow monitoring, manhole inspection, and smoke testing will
be stored for the duration of the survey.
1. Flow Data. Raw flow monitoring data will be reviewed and
transferred from solid state or magnetic tape to computer
storage. This data will be used in sub -routines to
calculate quantities of infiltration/inflow and basic
flows. Hydrographs of flow monitoring will be computer
plotted to provide a visual display of data.
2. Rainfall. Rainfall recorded during the study will be
entered in the computer. This data will be computer
plotted with the flow hydrograph to provide a visual
display of rainfall intensity and duration.
3. Inflow Investigation Information. Field information
obtained during smoke testing and related work tasks will
be stored and utilized in various analyses, correlated
with rate of flows vs. smoke testing and rainfall
simulation data.
4. Internal Inspection Data. Results of the internal
inspection will be input into the computer for data
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processing. Field logs and video tapes will be made
available at any time. At this time, records of major
defects will be made available to the City for
rehabilitation by in-house forces and/or for
implementation into plans and specifications for contract
repair.
VI. Phase 2. Phase 2 work will commence as soon as adequate wet
weather is available to provide the proper response in the sanitary
sewer system. It is estimated it will commence in early winter of
1989 and be complete in 1990. The tasks will include wet weather
flow monitoring and hydraulic modeling and analysis of the sanitary
sewer system, and a report detailing the monitoring and analysis
work, with recommendations for further sewer study and/or relief
sewers.
A. Flow Monitoring (Wet Weather).
1. Flow Monitoring Duration. The flow monitoring will
consist of approximately 20 identical monitors installed
and maintained for approximately 45 days.
2. Flow Monitoring Eauxoment. The flow monitoring equipment
will be the same as previously described in Phase 1.
B. Hydraulic Analysis. As determined by the Engineer and the
City, certain interceptors and mains (estimated to be 250,000
linear feet) will be evaluated to determine flow capacity
under existing conditions during certain storm events; and
then under future conditions during certain storm events after
varying degrees of extraneous water removal have been
accomplished by rehabilitation of the sewer system.
1. pata Input. In the drainage basins designated for the
flow monitoring, general flow routing patterns and
possible cross connections and relief sewer routes will
be established and input into the computer. A
computerized hydraulic network will be developed from
information gathered from existing as -built and record
drawings. In the absence of verifiable as built data,
the Engineer will default to minimum grade data or to a
reasonable determination of the probable grade utilizing
all as built and mapping data. Information collected
from these records will be recorded onto standard forms
and input into the computer analysis program.
Information input into the computer will include physical
data, such as rim elevation, invert elevation, pipe
diameter, length of pipe between manholes, and roughness
coefficients.
2 Hydraulic Model. A sanitary sewer computer model will
be used to evaluate system capacity, existing peak wet
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weather induced flows, and to identify either
1) overloaded line segments or 2) available remaining
pipe capacity. The software will be commercially
available, such as "SANSYS" by Civil Systems or "HYDRA"
by Pizer Software, and will be selected by the Engineer
subject to approval by the City. Selected design flows
will be input into the computer network model to evaluate
system behavior along main interceptors and sub -mains.
Flow routing will be dynamic and model real-time travel
of peak flows through the system to the outlet points.
The computer model will identify relief sewers required
and estimate cost for 1) parallel relief, 2) replacement,
or 3) rerouting if possible where bottlenecks occur.
Peak flow distribution within a basin will be made from
the rational formula and actual instantaneous flow rates
measured at keypoints during multiple storm events. Peak
flows will be determined from extrapolation of the
statistical relationship between measured flow (Q) and
rainfall intensity (i). There exists a third ungraphed
dimension which must be considered in the analysis, i.e.,
antecedent ground conditions. Special care will be given
to the antecedent ground -runoff conditions for each
minisystem to prevent any erroneous judgments being made
regarding the apparent flow vs. rainfall intensity
relationship.
Computer output reports will display existing system physical
description, capacity, surcharge capacity, and estimated
percentage hydraulic overload for predetermined rainfall
events.
C Report. The report will present a detailed description of all
tasks performed with results, conclusions and recommendations
taken from the flow monitoring and hydraulic analysis clearly
presented. The report will detail and rank the sub -basins
from the flow monitoring. Recommendations for additional
inflow reduction tasks will be made and costing provided. The
percent of utilization of the sanitary sewer lines
hydraulically evaluated (including overloading) will be
presented and recommendations for resolving inadequate
capacity made.
VII. Phase 3. Phase 3 field work will commence as soon as the
results from Phase 2 are available. It is estimated Phase 3 will
commence approximately March 1, 1990 and will continue through June
1990. The tasks will be determined by the results of the
monitoring and hydraulic and cost analysis, but will include
additional manhole inspection, smoke testing and TV inspection.
It will also include wet weather infiltration investigation work
such as flow isolation and wet weather inspections, where the
results of flow monitoring analysis show that they are needed.
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A. Manhole Inspection. Additional manhole inspections will be
accomplished as in Phase 1, where required.
B . Infiltration Investigation.
1. Flow Isolation. In those areas determined to have
possible excessive infiltration, "microsystems" of from
1,000 to 3,000 feet shall be delineated. Infiltration
will then be measured at microsystem key manholes by
taking "instantaneous" flow measurements during the early
morning hours. These measurements will be correlated
with continuous flow monitoring results. "Instantaneous"
flow measurements will be obtained using hand weirs as
follows:
a. Flow isolation shall consists of isolating a
designated reach of sewer during the early morning
hours (midnight to 6:00 a.m.) by measuring in the
sewer as necessary to determine infiltration rates.
b. Where practical, weiring shall be performed to
measure the flows. Where weiring is not practical,
the flow shall be measured by dipstick and velocity
measurements.
c. For each location where flow isolation is performed,
a flow isolation (WEIR) report shall be completed.
Then based on microflow isolation, a determination
will be made whether further flow isolation, manhole
inspection in wet weather, or TV inspection work is
required to locate infiltration sources. If
required, in some instances, flow isolation may be
accomplished on a segmental basis (manhole to
manhole).
2 Wet Weather Inspection. In areas of high incidence of
"rainfall -related" infiltration, inspection of manholes,
service lines, main lines, bypasses, etc., as required,
will be performed during wet periods after rainfall
events to specifically identify I/I.
C. Inflow Investigation. Inflow investigations will be
accomplished as previously described in Phase 1.
D . Jine Cleaning. Line cleaning
previously described in Phase 1.
E . TV Inspection. TV inspection
previously described in Phase 1.
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will be accomplished as
will be accomplished as