Item 9E - Final CITY OF Item 9E
SOUTHLAKE
MEMORANDUM
(June 20, 2017)
To: Shana Yelverton, City Manager
From: Rob Cohen, Director of Public Works
Subject: Approve a Professional Services agreement with RJN Group,
Inc., to conduct a Sanitary Sewer System condition
assessment in an amount not to exceed $227,200
Action
Requested: Approve a Professional Services agreement with RJN Group, Inc.,
to conduct a Sanitary Sewer System condition assessment in an
amount not to exceed $227,200.
Background
Information: In 2007, the City contracted with RJN Group, Inc. to perform a
comprehensive Sanitary Sewer Evaluation Survey (SSES). This
study was conducted over a period of three years with the purpose
of identifying any potential deficiencies in the City's wastewater
collection infrastructure.
Southlake's wastewater collection system consists of 208.74 miles
of pipe, 3,760 manholes, 13 wastewater lift stations and 8,770
service connections (8,737 are active). While the City's wastewater
collection systems in the southern basins are approximately 35
years old, and 18 years old in the northern basins, it is a best
management practice to evaluate the integrity of the collection
system approximately every ten years.
Wastewater collection systems are, by design, primarily non-
pressurized, gravity-flow pipeline networks. For that reason, defects
in pipes and other system components are not readily apparent as
they are in water distribution systems. In order to take advantage of
the natural terrain, these gravity systems often follow creeks and
other drainage ways. This placement makes them vulnerable to
external groundwater pressure resulting in the infiltration of
significant amounts of water where defects are present. Another
source of inflow into the system results during rain events when
manholes, cleanouts and other structures are subjected to flooding
and standing water as well as any illicit connections from rain
gutters.
Item 9E
Over the course of the last ten years, Wastewater personnel have
worked to complete corrective action items identified in the SSES to
maintain the wastewater system in good condition. Some of these
corrective items include point repairs on the sewer main;
elimination of direct open access points; installation of sealant
between manhole cover and concrete structure; and rehabilitation
of deteriorating manhole structures by applying an epoxy coating to
deter corrosion from hydrogen sulfide and methane gases.
In addition, per the U.S. Environmental Protection Agency (EPA),
municipalities are required to develop a comprehensive Capacity,
Management, Operation, and Maintenance (CMOM) Plan for their
wastewater collection systems. The CMOM identifies all aspects of
the wastewater collection system and the day-to-day operations as
well as future planning for growth.
In FY 2017, City staff worked with Freese & Nichols, Inc. to develop
Southlake's CMOM Plan. As part of the FY 2017 CMOM plan gap
analysis, it is necessary for the City to perform a current condition
assessment of the wastewater infrastructure. It should be noted
that the proposed condition assessment capitalizes on the results
of the original SSES to confirm corrective action has remedied any
deficiencies identified back in 2007.
The proposed condition assessment will aid the City in identifying
any other areas that need attention to prevent inflow and infiltration
(I/I) into the wastewater collection system. Excessive inflow and
infiltration increases the City's cost of treatment to the Trinity River
Authority (TRA) wastewater treatment facility. Therefore,
performing a condition assessment aids the City in corrective
measures and managing treatment costs.
Financial
Considerations: Funding for the Professional Services agreement with RJN Group,
Inc., to conduct a Sanitary Sewer System condition assessment in
an amount of $227,200 is partially available in CIP project account
00039 in the amount of $180,000. The balance to complete the
assessment may be transferred from the Utility CIP Residual
Account in the amount of$47,200 upon Council approval.
The study also includes temporary flow monitoring to aid the City in
identifying areas of current I/I concern with the intent of correcting
these to manage wastewater treatment costs, therefore, this study
may provide for cost avoidance of unnecessarily treating ground
water from inflow and infiltration.
Item 9E
Strategic Link: The approval of this Professional Services agreement links to the
City's strategy map relative to the focus area of Infrastructure. The
specific corporate objectives that are met by these services are to
(132) collaborate with select partners to implement service solutions
and (F2) invest to provide and maintain high quality public assets.
Citizen Input/
Board Review: N/A
Legal Review: N/A
Alternatives: City Council may approve or deny this Professional Services
agreement.
Supporting
Documents: Attachment A: RJN Group Proposal
Staff
Recommendation: Approve a Professional Services agreement with RJN Group, Inc.,
to conduct a Sanitary Sewer System condition assessment in an
amount not to exceed $227,200.
Staff Contact: Rob Cohen, Director of Public Works
Cristina McMurray, M.P.A, C.P.M, Deputy Director of Public
Works/Operations
Attachment A
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June 1, 2017
Cristina McMurray
Deputy Director Public Works Operations
1950 E. Continental Blvd.
Southlake,TX 76092
RE: Sanitary Sewer Flow Monitoring and Field Investigation Services
Dear Cristina:
Thank you for the opportunity to provide you with a proposal for flow monitoring sewer investigation
services for Southlake,Texas. We understand that the City is interested determining the capacity and
performance of the sanitary sewer system as a part of the City's overall CMOM Efforts. We are
proposing system-wide flow monitoring along with smoke testing and dyed water flooding in select
areas designated by Southlake staff.
The proposed flow monitoring scope includes twenty(20)gravity flow meters and five (5) rain gauges
proposed for a monitoring period of 60 days. A detailed scope of services for the Flow Monitoring and
Field Investigation Services in attached.The abridged scope of services for the flow monitoring is as
follows:
Flow Monitoring Equipment—The equipment will be redundant depth-velocity meters outfitted with a
pressure transducer, ultrasonic depth sensors and Doppler velocity sensor.This equipment will capture
flow rates under varying hydraulic conditions, such as back-up and surcharge.The equipment will be
activated to record the depth and velocity at 5 minute intervals.
Wireless Telemetry- Remote Terminal Units (RTU) shall be provided at each flow monitoring and rain
gauge location to remotely collect the data. On a daily basis, all data stored in the remote RTU will be
collected by the host system and available for viewing by authorized parties.
Installation —The sensors will be mounted on a thin metal ring inserted on the upstream pipe.The
cabling will be secured to the manhole walls and attached to a data logger at the top of the manhole for
easy access. Prior to leaving the site, each flow monitor will be configured and activated. Finally,the
equipment will undergo a series of diagnostic tests and calibrations to validate and confirm the meter
data.
Hydraulic Calibrations— Each monitored location will be calibrated at installation and during scheduled
visits,thereafter. Calibration involves comparing the returned sensor values against independent
devices to ensure that the hydraulic characteristics and various flow regimes will support the accuracy
level desired. A velocity profile will also be obtained during each calibration by measuring the
12160 Abrams Road, Suite 400 D. 972.437.4300 972.437.2707
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instantaneous velocity at pre-defined depths, and then integrated to derive an average for comparison
to the meters calculated average velocity.
Data Management and Maintenance— Each flow meter will be collected by the Host System daily and
the data shall be reviewed by the data analyst twice per week. During each review, data will be graphed
to check for inconsistencies, gaps, or adverse trends. In the event that a meter or sensor is not
performing correctly, a field crew will be dispatched to diagnose the problem and make necessary
adjustments or repairs.Any equipment found to be working improperly will either be repaired at the
site or replaced with a spare unit to minimize the data downtime. If necessary, a service visit will be
conducted during the monitoring period to obtain calibrations. All field activities are recorded on
standard field forms and provided at the end of the project.
Data Analysis and Quality Control — RJN engineers will analyze data from each monitoring site
immediately upon delivery from the field.The engineers will use various analytical tools, such as
hydrographs, scattergraphs, and flow balancing methods to verify the accuracy and precision of the
equipment, in addition to identifying unusual hydraulic events.The engineers will look for unique
hydraulic conditions such as bottlenecks, surcharging, suspected overflows, and excessive inflow and
infiltration. Indications of concern will be reported immediately.
Data Delivery— Within four weeks of the meter removal, RJN will submit a report summarizing the flow
data and our findings. Depth, velocity, and flow quantity data will be submitted in electronic format in
excel, .csv or in model format as you prefer.
12160 Abrams Road, Suite 400 D. 972.437.4300 972.437.2707
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Compensation—Compensation for providing these services will be based upon the following table:
Description Quantit Unit Unit Cost Cost
Project Administration 1 LS $17,050 $17,050
Flow Meter Investigation 20 Each $615 $12,300
Flow Meter Installation 20 Each $700 $14,000
Rain Gauge Investigation and Installation 5 Each $450 $2,250
FM Monitoring Period 1,200 Meter-Days $69 $83,256
RG Monitoring Period 300 Gauge-Days $21 $6,255
1/1 Hydraulc Analysis and Reporting 1 LS $24,579 $24,579
Flow Monitoring = $159,690
Project Administration 1 LS $8,690 $8,690
Public Relations/Smoke Notices 77,000 Linear Feet $0.15 $11,550
Smoke Testing 77,000 Linear Feet $0.50 $38,500
Dyed Water Flooding 10 Each $645 $6,445
Data Processing / Management 1 LS $6,750 $6,750
Source Defect Anaysis and Reporting 1 LS $6,300 $6,300
Field Investigations = $78,235
Flow Monitoring and Field Investigation as 2 separate projects = $237,925
NOTE: If both projects are combined into a larger project with one final report there's a savings
in Project Administration and Reporting Costs
Flow Monitoring and Field Investigation as 1 project = $227,200
We appreciate you considering our services and thank you for the opportunity to submit this proposal.
We look forward to working with you on this project. Should you have any questions, please do not
hesitate to contact me.
CITY OF SOUTHLAKE,TEXAS RJN GROUP, INC.
By: By: (s 4o"\,
Laura Hill, Mayor Daniel Jack on, P.E., Vice President
ATTEST:
By:
Lori Payne,TRMC City Secretary
12160 Abrams Road, Suite 400 D. 972.437.4300 972.437.2707
PROPOSAL FOR ENGINEERING SERVICES
CITY OF SOUTHLAKE FLOW MONITORING AND SEWER INVESTIGATION
SCOPE OF SERVICES
A. SCOPE OF SERVICES
The Services to be provided under this PROPOSAL shall consist of sanitary sewer evaluation study
(SSES) services including system-wide flow monitoring and targeted field investigation services to
complement the City's CMOM efforts.
Flow Monitoring
A.1.1 Project Administration
The Engineer shall coordinate the overall work of the project to include all field inspections
and engineering analysis. The Engineer shall provide monthly progress reports that will
show the percent completion of each task. A bi-monthly progress meeting with the CITY
OF SOUTHLAKE will be conducted.
A.1.2 Field Verification
Prior to beginning the flow monitoring project, the Engineer will verify sewer line
interconnectivity and sewer flow direction at various locations across the collection system to
confirm proposed sewer shed delineations and understand impact of the sewers upstream of
proposed flow monitoring locations. The Engineer shall conduct field investigations to verify the
suitability of each potential monitoring location.
A.1.3 Flow Monitoring Services
Prior to installing flow monitors, the Engineer will develop a now monitoring plan. The flow
monitoring plan will include the preliminary monitoring sites selected from a review of the
City's existing sewer maps. These sites will be based on a distribution of approximately
25,000 to 60,000 linear feet per flow monitor. Special attention areas or split now conditions
may require additional flow monitors. Potential flow monitoring sites will be identified with
consideration given to basin size, evidence of surcharging, overflow locations, projected
maintenance activities, and other factors. Potential and alternate sites will be inspected and the
site hydraulics evaluated.
The Engineer shall conduct field investigations to verify the suitability of each potential
monitoring location. The field investigations will verify sewer line interconnectivity and sewer
flow direction in various locations across the collection system and in the proposed meter
locations. The Engineer shall prepare a site investigation sheet for each selected site and shall
submit to the CITY OF SOUTHLAKE.
After approval of the recommended sites, the Engineer shall install and maintain the meters for
Scope of Services— Southlake
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a 60-day period. The Engineer shall also select rain gauge monitoring sites and install
continuous recording rain gauges.
Flow monitoring will be performed utilizing ADS or equal monitors capable of measuring both
depth and velocity of flow. Tipping bucket gauges will be installed to obtain rainfall distribution
data.
A total of twenty (20) Flow Meters and five (5) tipping bucket rain gauges are proposed for
the study.
A.1.4 Flow Data Management
During the flow monitoring study, flow data will be continually reviewed and analyzed in order to
assess the accuracy and quality of the data.
A.1.5 Flow Data Analysis
A.1.5.1 Rainfall Relationship
Adequate rainfall will be necessary to establish the relationship between peak inflow
and rainfall intensity. This relationship will be used to determine the impact on the
collection system during wet weather and high groundwater conditions. A correlation
of flow and rainfall intensity will be made using the area-coefficient method of
analysis. It is anticipated that a minimum of three storm events that do not cause
surcharging of the collection system will be recorded during the 60-day monitoring
period.
Data from the continuously recording rainfall gauges will be used to establish the
intensity of rainfall and duration for each storm event. The Thiessen Method for rainfall
distribution analysis will be used.
For each monitoring site, data developed as part of the analysis will include:
- Average Dry Weather Diurnal Curve Flows for weekdays and weekends
- Rainfall /Wet Weather Wastewater Flow Correlations for selected storm events during
the monitoring period
- Design peak inflow rate at the design storm event
- Capacity analysis at the monitoring sites
A.1.5.2 Based on the flow data analysis the various basins will be ranked according to
their inflow contribution and infiltration contribution. The I&I ratings shall be used to
develop a prioritization for each basin. Using the various rankings, the ENGINEER shall
provide the CITY OF SOUTBLAKE with a recommendation for the basins in which to
perform SSES activities.
A.1.5.3 Incorporate flow analysis and flow projections will be summarized in a
Technical Memorandum and submitted to the CITY OF SOUTBLAKE for review.
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SSES Field Investigation proposed for
Field Investigation Work will consist of smoke testing, dye water flooding and data analysis.
A.2.1 Project Administration
The Engineer shall coordinate the overall work of the project to include all field inspections,
engineering analysis. The Engineer shall provide monthly progress reports that will show the
percent completion of each task. A bi-monthly progress meeting with the CITY OF
SOUTHLAKE will be conducted.
A.2.2 Public Information Program
The Engineer shall conduct a public notification program prior to the field inspections in order
to minimize potential alarm over the presence of field personnel in backyards and over the
potential for entry of test smoke into the various premises.
A.2.2.1 The ENGINEER will complete press releases to submit to the CITY OF
SOUTHLAKE, hold informational meetings, and coordinate with CITY OF
SOUTHLAKE's staff.
A.2.2.2 Notification will be given to the CITY OF SOUTHLAKE, building owners, and
residents by the distribution of door hangers at least 48 hours prior to commencing
smoke testing activities. The local fire department, police department, emergency
vehicle services (EMSA) and the CITY OF SOUTHLAKE staff will be notified each
day prior to tests through the use of facsimile machines/E-Mail.
A.2.2.3 Special coordination with property managers will be necessary for hospitals,
medical offices, banks, government buildings, and other large commercial facilities.
A.2.2.4 The ENGINEER will respond to all telephone calls by building owners or
occupants during all active phases of the project.
A.2.3 Manhole Inspections—Not Proposed at this time
A.2.4 Smoke Testing
A.2.4.1 Smoke testing will be conducted using dual axial blowers. Smoke testing lengths
shall be limited to one line segment between the upstream and downstream blower
locations. Each 12-inch diameter and smaller segment shall be isolated by sandbagging.
Smoke candles shall be used to generate smoke for the smoke testing. Segments totaling
less than 500 feet may include straight through manholes. Smoke testing will be
performed only during dry ground periods which are anticipated to be between July and
September.
A.2.4.2 Flags shall be placed at observed smoke locations and digital images shall be
captured. All defects identified by smoke testing shall be flagged and photographed.
Smoke defect locations shall be recorded on sketches or by obtaining GPS
coordinates. All private sector smoke defect images shall be entered into the field
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inspection database.
A.2.4.3 Main line defects and service lateral defects shall be carefully scrutinized to
ensure that a conservative determination of public vs. private side defects is made. If
necessary the line shall be earmarked for television inspection.
A.2.4.4 During the smoke testing, each building in the vicinity of the line segment will
be observed for evidence of illegal or illicit connections, or other defects. All such
defects shall be noted on the smoke test form. Where suspect defects are identified but
are not confirmed by the smoke test, the building address, type, and suspected defect
shall be noted. All such buildings will be submitted to the CITY OF SOUTHLAKE as
candidates for a detailed building inspection or dyed water flooding. Upon review and
approval by the CITY OF SOUTHLAKE these buildings will be subsequently inspected
by the Engineer.
A.2.5 Dye Water Flooding
A.2.5.1 Line segments requiring dye water testing will be identified on the basis of smoke
test results. Prior to initiating dye water testing, a list of line segments recommended for
dye water testing will be provided to the CITY OF SOUTHLAKE for review and
approval. The line segments on the list will be annotated as to the priority and reason for
recommendation. It is anticipated that dyed water flooding of suspected downspouts,
drains, and storm sewers in the downtown area may be performed in lieu of smoke testing.
A.2.5.2 Dyed water flooding shall be conducted at selected locations prior to televised
inspection to verify the existence of inflow and infiltration sources. Dye testing will also
be conducted concurrently with television inspections on those line segments approved by
the CITY OF SOUTHLAKE for dye testing.
A.2.5.3 The dye water will be induced into the line by flooding storm sewers and drainage
ditches. Sufficient time will be allowed for the source to activate, at which time the
television inspection equipment will be introduced into the line segment.
A.2.6 Cleaning and Television Inspection—Not Proposed at this time
A.2.7 Data Management/ Quality Assurance
A.2.7.1 Each field inspection form will be reviewed to ensure that the field data is
complete and free from obvious errors or inaccuracies. Smoke test photos will be
reviewed to ensure that background reference features appear in the photo. Dyed water
forms will be reviewed to ensure that they correlate with the CITY OF SOUTHLAKE's
atlas. Data entry will be performed concurrently with the field inspections to ensure that
errors are identified, addressed, and corrected as soon after the inspection was performed
as possible.
A.2.7.2 All smoke testing, dyed water and any other observed defects shall be captured
with a digital camera and loaded on to a CD or Flash drive for delivery to the CITY OF
SOUTHLAKE.
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A.2.7.3 Discrepancies between the CITY OF SOUTHLAKE's sewer atlas and actual
field conditions will be recorded on standard forms and periodically delivered to the
CITY OF SOUTHLAKE.
A.2.8 Defect Analysis and Technical Memorandum:
At the conclusion of the field investigation services, an engineering analysis of field survey
data shall be performed to develop recommendations for prioritizing UI source repairs.
A description of field investigations, engineering analysis, and recommended action to reduce
I/I will be included.
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