HomeMy WebLinkAbout03. Draft PP to amend agreement with V&A Consulting Engineers for Collection System Modeling UpgradeCentral Contra Costa Sanitary District
' BOARD OF DIRECTORS •
POSITION PAPER
Board Meeting Date: SEPTEMBER 17, 2015
Subject: AUTHORIZE THE GENERAL MANAGER TO EXECUTE AN AGREEMENT
AMENDMENT IN THE AMOUNT NOT TO EXCEED $400,000 WITH V &A
CONSULTING ENGINEERS FOR THE COLLECTION SYSTEM MODELING
UPGRADE, DISTRICT PROJECT 8418
Submitted By:
Justin J. Waples, Assistant Engineer
Initiating Dept. /Div.:
Engineering and Tech Services /Planning
& Development Services
REVIEWED AND RECOMMENDED FOR BOARD ACTION:
N. Hodges — Associate Engineer
D. Frost — Senior Engineer
D. Gemmell — Planning and Development Services Division Manager
JM. Petit — Director of Engineering and Technical Services
Roger S. Bailey
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.
RECOMMENDATION: 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.
FINANCIAL IMPACTS: The total anticipated cost for winter 2015 -16 flow monitoring by
V &A Consulting Engineers is $400,000. Under the existing agreement, V &A Consulting
Engineers performed the winter 2014 -15 flow monitoring for $160,000. The total cost for
winter 2014 -15 and winter 2015 -16 flow monitoring is $560,000. There are adequate
funds in the Fiscal Year 2015 -16 Collection System Program Capital Improvement
Budget (CIB) to fund the additional flow monitoring work.
PROJECT PRIORITY: Critical, as shown in the CIB.
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. The Comprehensive Wastewater Master Plan
(CWMP) will have to rely on a model calibration using the limited winter 2014 -15 flow
monitoring results, which did not capture adequate storm data and did not represent
saturated soil conditions.
Page 1 of 5
POSITION PAPER
Board Meeting Date: SEPTEMBER 17, 2015
Subject: AUTHORIZE THE GENERAL MANAGER TO EXECUTE AN AGREEMENT
AMENDMENT IN THE AMOUNT NOT TO EXCEED $400,000 WITH V &A
CONSULTING ENGINEERS FOR THE COLLECTION SYSTEM MODELING
UPGRADE, DISTRICT PROJECT 8418
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 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.
The InfoWorks dynamic model is being built for the main backbone trunk sewers. This
includes 290 miles of trunks and interceptors that convey wastewater flows to the
District's wastewater treatment plant in Martinez. The CWMP consultant is tasked with
completing the model network configuration. 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.
District's Flow Monitoring 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 included conducting
limited flow monitoring during winter 2014 -15 and determining if additional flow
monitoring is recommended.
Page 2 of 5
POSITION PAPER
Board meeting Date: SEPTEMBER 17, 2015
Subject: AUTHORIZE THE GENERAL MANAGER TO EXECUTE AN AGREEMENT
AMENDMENT IN THE AMOUNT NOT TO EXCEED $400,000 WITH V &A
CONSULTING ENGINEERS FOR THE COLLECTION SYSTEM MODELING
UPGRADE, DISTRICT PROJECT 8418
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 a nine -week duration. 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 winter 2014 -15 flow monitoring tributary area covered by the 36 flow meters
averages to a large area per meter (approximately 47 miles of tributary sewer per flow
meter). With large tributary areas, it is difficult to reflect actual variations in response
within the tributary areas. The relatively small number of flow meters used in winter
2014 -15 was to mitigate the high probability of a dry winter.
The District's CWMP consultant and District staff are recommending additional flow
monitoring during the upcoming 2015 -16 wet weather season. The monitoring would
include a repeat of most sites from the 2014 -15 flow monitoring program as well as new
sites identified from the results of the 2014 -15 flow monitoring. Specifically, monitoring
at areas showing significant flow response is recommended to 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.
• 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
Page 3 of 5
POSITION PAPER
Board Meeting Date: SEPTEMBER 17, 2015
Subject: AUTHORIZE THE GENERAL MANAGER TO EXECUTE AN AGREEMENT
AMENDMENT IN THE AMOUNT NOT TO EXCEED $400,000 WITH V &A
CONSULTING ENGINEERS FOR THE COLLECTION SYSTEM MODELING
UPGRADE, DISTRICT PROJECT 8418
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, 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
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.
Including the amount spent to date, the project can be completed within the CIB Total
Project Cost of $949,998. The Collection System Modeling Upgrade, District
Project 8418, is included in the FY 2015 -16 CIB on page CS -24 with a total project cost
of $949,998. Staff has conducted a budget analysis of the FY 2015 -16 Collection
System Program budget and concluded that adequate funds are available, as shown
below:
Page 4 of 5
POSITION PAPER
Board Meeting Date: SEPTEMBER 17, 2015
Subject'. AUTHORIZE THE GENERAL MANAGER TO EXECUTE AN AGREEMENT
AMENDMENT IN THE AMOUNT NOT TO EXCEED $400,000 WITH V &A
CONSULTING ENGINEERS FOR THE COLLECTION SYSTEM MODELING
UPGRADE, DISTRICT PROJECT 8418
FY 2015 -16 Collection System (CS) Program Allocation Budget:
Authorized Estimated Allocations for Projects $ 24,650,000
Supplemental Board Authorizations: $ 0
Allocations Returned from Closeouts: $ 0
Total Board Authorized Allocations: $ 24,650,000
FY 2015 -16 Allocations to Date for CS Program: $ 5,212,000
This Allocation for DP 8418: $ 400.000
Remaining Unallocated Budget for CS Program: $ 19,038,000
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.
COMMITTEE RECOMMENDATION: The Engineering and Operations Committee
reviewed this project at its meeting on August 26, 2015, and recommended
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.
Page 5 of 5
Item No. 3
Flow Monitoring Update and
Request for
2015/16 Flow Monitoring
,,,c,* E14 GS D
August 26, 2015
Engineering & Operations Committee
PubhC Health and the En —o—ent
District Modeling Background
Steady State Model Sewer Steady State Model Enhanced
Network Analysis Program SNAP & GIS Interface Dynamic Modeling
(SNAP) (ArcSNAP) (InfoWorks)
151 Major Flow
2n1 Major Flow 3'd Major Flow
Monitoring
1
Monitoring Monitoring
Steady State
Model
Dynamic
Pipe Age & y
Calibration
I/1 Correlation Model Initial
Calibration
2014/2015 Flow Monitoring
• Installed 36 meters, 5 rain gauges
• Installation from February 4 to 6
• Monitoring Duration: 9 weeks (ended April 9)
• Distributed
throughout
Collection
System
• Along 290 -Mile
Backbone
Trunk System
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8/21/2015
Feb 6 -8, 2015 Storm Event
Example: High Response
2014/2015 Flow Monitoring Results
• Did not experience saturated soil conditions
• Preliminary PHWWF peaking factors
• Identified some areas of high 1/1
• Data for base wastewater flow rates
• Limited data for initial model calibration
Additional Flow Monitoring is
Required
• Capture entire storm w/ saturated conditions
• Potentially capture a larger storm than Feb 6 -8, 2015
• Clarify 1/1 in high response areas
• Reduce tributary area per meter and miles per meter
• Accurate model calibration for:
PHWWF for Comprehensive Wastewater Master Plan
Confirm "Expansion" projects in 10 -Year CIP ($35.7M)
Identify any new "Expansion " - required projects
Continued evaluation of development impacts
Consistency with other
Flow Monitoring Programs
8/21/2015
Flow Monitoring Agreement
Flow Monitoring 2014/15 $160,000
$295,000 (9 weeks)
Flow Monitoring 2015/16 + $105,000 (4 weeks contingency)
$400,000
New Agreement Ceiling
$560,000
Recommendations
• Perform 2015/2016 Flow Monitoring with 70 Meters
for 9 weeks (+ 4 week contingency)
• Use calibrated model to 1) confirm & identify
capacity projects and 2) ongoing evaluations of
development impacts
• Board Authorization for the General Manager to
Execute Flow Monitoring Amendment for $400,000
8/21/2015