HomeMy WebLinkAbout09.a. Amend agreement with V&A Consulting Engineers re flow monitoringCentral Contra Costa Sanitary District
' BOARD OF DIRECTORS , Q.
POSITION PAPER
Board Meeting Date: SEPTEMBER 17, 2015
Subject: AUTHORIZE THE GENERAL MANAGER TO EXECUTE AN AGREEMENT
AMENDMENT TO INCREASE THE COST CEILING FROM $160,000 UP
TO $560,000 WITH V&A CONSULTING ENGINEERS FOR THE
COLLECTION SYSTEM MODELING UPGRADE, DISTRICT PROJECT
8418
Submitted By: Initiating Dept. /Div.:
Dan Frost, Senior Engineer Engineering & Technical Services /
Planning & Developme ervices
REVIEWED AND RECOMMENDED FOR BOARD ACTION:
D. Gemmell — Planning & Development Services Division Mgr. I .A* K.
E. Lopez — Capital Projects Division Manager Roger S. Bailey
JM. Petit — Director of Engineering & Technical Services General Manager
ISSUE: Board of Directors' authorization is required for the General Manager to
execute an amendment to an existing agreement in the amount greater than $100,000
or 15 percent above the original agreement amount.
BACKGROUND:
Collection System Hydraulic Model
The District's collection system hydraulic model is a critical tool used to predict flows,
analyze impacts of point discharges, investigate impacts of proposed and future
development and provide crucial flow information for strategic planning, asset
management and Capital Project design for the District's collection system and
wastewater treatment plant.
The District began the conversion to a new dynamic model in 2012 from the existing
steady state model, ArcSNAP. The new dynamic model will more accurately simulate
the hydraulic complexities of the District's collection system and will bring the District up
to current hydraulic modeling standards used in the wastewater industry. Most public
agencies, including the City of San Jose, San Francisco Public Utilities Commission,
Sacramento Regional Sewer District, and many others, have converted to dynamic
modeling. Before the model can be confidently implemented, two processes must be
completed: 1) the model network configuration; and, 2) the model calibration.
To verify that the model network matches field conditions and correctly models the
network's hydraulic response, it is critical that flow monitoring is performed and that the
model is calibrated to the flow monitoring data.
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POSITION PAPER
Board Meeting Date: SEPTEMBER 17, 2015
subject: AUTHORIZE THE GENERAL MANAGER TO EXECUTE AN AGREEMENT
AMENDMENT TO INCREASE THE COST CEILING FROM $160,000 UP
TO $560,000 WITH V&A CONSULTING ENGINEERS FOR THE
COLLECTION SYSTEM MODELING UPGRADE, DISTRICT PROJECT
8418
District's Flow Monitorinq History
System -wide flow monitoring has been conducted twice over the past 30 years, in 1985
and in early 2005. The first flow monitoring (1985) was the foundation for what became
the District's steady state hydraulic model. The second flow monitoring (2005) was
focused on the relationship of pipe deterioration to inflow /infiltration, particularly for
sewers constructed between 1985 and 2004. In late 2014, the District began a flow
monitoring program with the intent of calibrating the new dynamic model.
The current flow monitoring program, approved by the Board in 2014, included
conducting limited flow monitoring during winter 2014 -15 and determining if additional
flow monitoring is recommended.
2014 -15 Flow Monitoring Results
The 2014 -15 flow monitoring was conducted between February 2015 and mid -April
2015 at 36 sites on the collection system trunk sewers for nine weeks. Winter 2014 -15
was a continuation of drought conditions and rainfall was relatively low compared to a
typical wet weather season. Only two storm events were captured during the monitoring
period, with each event preceded by significant dry periods. When soils are not
saturated, the rate of inflow /infiltration tends to be underestimated. The flow data
obtained from the winter 2014 -15 flow monitoring provides a basis for an initial
quantification of inflow and infiltration response in the collection system. However, the
results did not represent saturated soil or maximum response conditions which are
needed for developing a design storm event response for accurate model calibration.
The District's CWMP consultant and District staff are recommending additional flow
monitoring during the upcoming 2015 -16 winter season, which is forecasted to produce
more wet weather than the past winter. The monitoring would include areas showing
significant flow response during the past winter and would provide hydraulic data at a
level of refinement necessary to calibrate the model for wet weather events, particularly
for smaller trunk sewer areas and in areas with high infiltration and inflow.
Benefits of the additional flow monitoring include:
• System -wide flow data for storm events under more favorable (wetter winter)
antecedent conditions.
• More accurate model calibration and wet weather flow predictions for both large
and small trunk lines.
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POSITION PAPER
Board Meeting Date: SEPTEMBER 17, 2015
subject: AUTHORIZE THE GENERAL MANAGER TO EXECUTE AN AGREEMENT
AMENDMENT TO INCREASE THE COST CEILING FROM $160,000 UP
TO $560,000 WITH V&A CONSULTING ENGINEERS FOR THE
COLLECTION SYSTEM MODELING UPGRADE, DISTRICT PROJECT
8418
• More refined and reliable assessment of hydraulic deficiencies and resulting
capital improvements.
This winter has a higher probability of producing a typical or normal wet weather
pattern. On July 9, 2015, the National Oceanic and Atmospheric Administration Climate
Prediction Center announced an "El Nino" advisory indicating El Nino conditions are
presently observed, and stated there is a 90 percent chance the El Nino event will last
through the northern hemisphere winter of 2015 -16. El Nino events typically are
associated with above normal precipitation in California and other states.
The flow monitoring planned for this winter is necessary to assess the hydraulic
behavior of the present collection system infrastructure and calibrate the new collection
system model to enable representative simulations of base sewer flows and peak
design event sewer flows in the new InfoWorks® model. The District's hydraulic model
is used frequently to assess the hydraulic impact of new commercial developments on
District sewers and to identify capacity - related capital improvement projects. As part of
the CWMP, the calibrated model will be used to identify potential new capacity - related
capital improvements and to confirm the $35.7M in capacity - related (expansion) capital
improvements currently identified in the District's 10 -year Capital Improvement Plan.
Consultant Selection
In 2014, using a competitive selection process, District staff selected V&A Consulting
Engineers to conduct flow monitoring. On December 18, 2014, the Board approved an
Engineering Services Agreement with V &A Consulting Engineers to conduct 2014 -15
flow monitoring in an amount not to exceed $160,000. The scope of work also included
an option for 2015 -16 flow monitoring at the District's discretion that includes 70 flow
meters and five rain gauges at a cost of $295,000 for a period of nine weeks. Because
of the uncertainty of weather conditions, an additional four weeks of monitoring has
been negotiated with V&A Consulting Engineers as a contingency for a cost of
$105,000. This brings the total cost of 2015 -16 wet weather flow monitoring to
$400,000 for a period of 13 weeks. The new contract ceiling will be $560,000.
Staff intends to work with V &A Consulting Engineers, in consultation with weather
forecasts, to install flow meters after soils have been estimated to be saturated and wet
weather is expected. If the wet weather season is typical, nine weeks of flow monitoring
is sufficient and the meters will be removed. However, if storms do not materialize as
forecasted or storms are significantly spread out, flow monitoring may continue for the
entire 13 week period. Ideally, we will collect flow data for multiple, significant storm
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POSITION PAPER
Board Meeting Date: SEPTEMBER 17, 2015
subject: AUTHORIZE THE GENERAL MANAGER TO EXECUTE AN AGREEMENT
AMENDMENT TO INCREASE THE COST CEILING FROM $160,000 UP
TO $560,000 WITH V&A CONSULTING ENGINEERS FOR THE
COLLECTION SYSTEM MODELING UPGRADE, DISTRICT PROJECT
8418
events with saturated soil conditions. If there are no significant storms forecasted after
nine weeks, flow monitoring will be terminated and the four -week contingency amount
of $105,000 will not be spent. Prior to authorizing the additional four weeks, staff will
present the status of the flow monitoring effort for winter 2015 -16 to the Engineering &
Operations Committee for discussion.
The CIB provides for contingency funding for capital projects. The program contingency
is set aside in a separate account and used for new projects not identified in the CIB, or
to fund budget overruns, and /or pay for urgent/emergency work as needed. The
authorization limits for contingency spending are shown and approved annually in the
CIB.
Project Priority
Critical, as shown in the CIB.
CEQA: The Board concluded at the April 3, 2014, Board meeting that this project is
exempt from the California Environmental Quality Act (CEQA) under District CEQA
Guideline Section 15306 as the project involves data collection that will not result in a
serious or major disturbance to an environmental resource.
ALTERNATIVES /CONSIDERATIONS: Do not perform flow monitoring for winter 2015-
16. This alternative is not recommended, as there will be limited data to calibrate the
new collection system hydraulic model. Staff relies on the model to conduct day to day
operation and provide services to potential new development and customers. A
calibrated model is desirable to provide more accurate and timely response to
customers. Furthermore, the Comprehensive Wastewater Master Plan (CWMP) will
also rely on a calibrated model to determine potential capacity deficiencies of the
collection system.
FINANCIAL IMPACTS: The total estimated project cost for the Collection System
Modeling Upgrade project in the Fiscal Year (FY) 2015 -16 Capital Improvement Budget
(CIB) is $950,000. This amendment will increase the budget from $950,000 to
$1,350,000. The FY 2015 -16 Collection System Program Contingency Account
originally had $900,000 budgeted. To date the remaining contingency is $660,000. An
allocation of $400,000 to the Collection System Modeling project is needed to fund this
amendment. This will leave a balance of $260,000 in the Collection System program
contingency account.
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POSITION PAPER
Board Meeting Date: SEPTEMBER 17, 2015
Subject: AUTHORIZE THE GENERAL MANAGER TO EXECUTE AN AGREEMENT
AMENDMENT TO INCREASE THE COST CEILING FROM $160,000 UP
TO $560,000 WITH V&A CONSULTING ENGINEERS FOR THE
COLLECTION SYSTEM MODELING UPGRADE, DISTRICT PROJECT
8418
By using contingency, this project will not delay or defund other projects within the
Collection System Program. The projected cash flow and total estimated expenditures
for the Collection System Program are within the amount approved in the CIB.
COMMITTEE RECOMMENDATION: The Engineering and Operations Committee
reviewed this project at its meeting on August 26, 2015, no recommendation was
provided.
RECOMMENDED BOARD ACTION: Authorize the General Manager to amend an
existing Engineering Services Agreement with V &A Consulting Engineers, Agreement
No. 042498, in an amount not to exceed $400,000, increasing the contract ceiling to
$560,000 for the Collection System Modeling Upgrade, District Project 8418.
Attached Supporting Document.,
1. PowerPoint Presentation
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