HomeMy WebLinkAboutMurray Smith - Task Order No. 5 - NW Svc Area Capacity AnalysisTASK ORDER NO. 5
Reviewed By: Z -//7 City Project Code: y5b•9 D• lo(as-,5(�. Co5/Io
REGARDING GENERAL AGREEMENT BETWEEN CITY OF PASCO
AND
MURRAY, SMITH & ASSOCIATES, INC.
Project Description:
The professional engineering services associated with this Task Order 5 are for further evaluation of
capacity limitations in the City's wastewater collection system to serve anticipated future development
within the existing service area. The key element of this analysis is the capacity impacts with adjusting the
orientation of the diversion manhole at Chapel Hill Blvd and Broadmoor Blvd as recommended in the 2014
Comprehensive Sewer Plan.
Scope of Services:
See Attachment 1.
Time of Performance:
Work will be completed within 2 months of the City's notice to proceed.
Fee for Services:
On call engineering services will be billed on a time and materials basis with a total estimated budget of
$8,750, which shall not be exceeded without prior written authorization from the City. Compensation and
payment is per the On -Call Municipal Engineering Services, Professional Services Agreement.
Proposed: 14UI j 2SZG / -7
Muko, 9mith & Associates, Inc. Date
Joseph Foote, Senior Engineer, Associate
Approved: 95 2a !44&
sco
Dave Zabell, City Manager
Professional Services Agreement- Murray, Smith & Associates, Inc.
On -Call Municipal Engineering Services
9-122.11-1
Date
Page 1 of I
ATTACHMENT 1
SCOPE OF SERVICES
for the
CITY OF PASCO
EXISTING NORTHWEST SERVICE AREA CAPACITY ANALYSIS
This Scope of Services is for professional services between Murray, Smith & Associates, Inc.
(MSA) and the City of Pasco, Washington (City). The intent of this work is to assist the City
with further evaluation of capacity limitations in the northwest area of the wastewater
collection system to serve planned and anticipated future development. Key element of this
analysis are the capacity impacts associated with adjusting the orientation of the diversion
manhole at Chapel Hill Boulevard and Broadmoor Boulevard as recommended in the 2014
Comprehensive Sewer Plan.
BACKGROUND
MSA completed a Comprehensive Sewer Plan Update for the City in 2014. To address
capacity limitations for serving the existing and defined growth area in the northwest area of
the City two improvements were recommended. One was adjusting the upstream diversion
structure at Chapel Hill Blvd and Broadmoor Blvd to convey flows to the West Pasco Trunk
Sewer to address future capacity limitations in the Road 44 Interceptor. The other
improvement project included approximately 9,200 feet of 30 -inch sewer trunk line that
would extend the West Pasco Trunk Sewer, which is reviewed under the On -Call Municipal
Engineering Services, Professional Services Agreement, Task Order No. 4. This is to provide
service to the areas northwest of I-182, which includes the area west of Road 52 and north of
Powerline Road.
The City wants to further evaluate the proposed adjustment of the diversion manhole
improvement to confirm the available capacity in the Road 44 Interceptor and existing West
Pasco Trunk under existing and future (20 year) conditions. Based on available capacity of
the collection system in the northwest area, the City will better understand the benefits and
impacts of implementing the diversion to growth within its existing service area.
SCOPE OF SERVICE
Task 1— System Capacity Analysis
MSA will review the impacts of adjusting the orientation of the upstream diversion structure
at Chapel Hill Boulevard and Broadmoor Boulevard on the Road 44 Interceptor and existing
West Pasco Trunk capacity. MSA will use the sanitary sewer loading and flow rates
developed for the 2014 Comprehensive Sewer Plan, which incorporates updated planning
information from Task Order No. 4 with the additions of the proposed full build out of the
City of Pasco, WA MURRAY, SMITH & ASSOCIATES, INC. Diversion Downstream Analysis
January 2017 Engineers/Planners 1 of 2
DNR property as well as including previous development analysis loadings that MSA has
completed over the past 3 years. The existing and future system models will be updated to
include the refined flow rates for dry and wet weather conditions. Model scenarios will be
created and simulated for two future condition, under existing conditions and with the
diversion in place. The analysis will identify available capacity for the sewer collection
system serving the existing Northwest Service Area and any potential sewer capacity
deficiencies associated with the diversion. Specifically determining the available capacity in
the Road 44 Interceptor and existing West Pasco Trunk based on the change in sewer
diversion. System deficiencies will be based on City design criteria related to maximum
water depth to pipeline diameter ratios during peak dry weather and maximum surcharging
allowances during peak wet weather. Any locations where pipelines or manholes exceed the
accepted City design criteria will be identified.
Assumptions
MSA will utilize the existing hydraulic model without modification except for the
flow/loading update for the full buildout of the DNR property and previous
development analysis over the past 3 years. MSA will utilize the design standards
developed for the Comprehensive Sewer Plan Update in the analysis. Future (20 year)
dry and wet weather conditions will be evaluated.
This evaluation does not include reviewing alternative alignment or performing cost
comparisons.
Deliverables
• A final technical memorandum summarizing the analysis will be provided in
electronic format.
City of Pasco, WA MURRAY, SMITH & ASSOCIATES, INC. Diversion Downstream Analysis
January 2017 Engineers/Planners 2 of 2