Sewer Pump Station Generator Replacement
Project Status
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Project Details/Neighborhood
Pump Stations 23 & 25
Background
On-site back-up generators provide reliable and cost-effective back-up power for pump stations serving the sewer system. Generators have a useful life of 25 to 30 years. This ongoing program replaces a generator each year. By 2023, generators will have been replaced at each pump station.
Description
Ongoing program to replace generators that provide emergency power at sewer pump stations.
Construction Project Timeline (Target Completion Date)
Complete design Q2 2022
Estimated Budget
$51,000
Contact
Christopher Marks, City of Mercer Island Utilities Engineer: chris.marks@mercerisland.gov
Status Updates
May 2, 2024
The City’s contracted arborist for the project, Urban Forestry Services | Bartlett Consulting (UFS|BC) has taken inventory of the trees within the project limits. UFS|BC’s recommendations for tree protection and/or removal are necessary to secure project approval from the City’s planning department. RH2 Engineering, continues work to incorporate the City’s latest plan review comments into the design.
October 2023
Staff from RH2 Engineering’s design team re-visited pump stations 23 and 25 this month to ensure all site-specific challenges are addressed during final design. Delivery of 100% project design documents is expected by the close of 2023.
August 2023
A project milestone was reached this month with RH2 Engineering’s delivery of 50% design documents. Based on the preliminary design requirements, City staff can now begin procurement of long lead time items such as the diesel generators and transfer switches for both pump stations.
July 2023
RH2 Engineering has provided the technical memos necessary for processing of the Shoreline Exemption Permits at both pump station 23 and 25. City staff will work to finalize the permits in the following weeks. While updated fire codes, generator design, and access requirements have delayed the project, delivery of 50% design plans and specifications by RH2 Engineering are expected by middle August.
April 2022
RH2’s staff went out in March to pump stations 23 and 25 to perform a critical areas evaluation associated with environmental permitting requirements. They will continue to assist with permits for this project.
February 2022
A Shoreline Exemption Permit is required for this replacement. This entails a critical area review by a qualified professional. The City has amended the scope of work to add RH2’s permitting assistance.
Staff also met with RH2 and will look into pre-purchasing the equipment ahead of construction, as the lead times are over 52 weeks.
November 2021
In October, RH2 Engineering visited both pump station sites. The project will replace both generators almost like-for-like back into the existing underground vaults, however, the City was recently informed that the new generator options are of a slightly larger size and this may impact the electrical spacing requirements in the underground vaults. Additionally, fire codes have changed, so external ventilation for the fuel tanks is needed. Before design work continues staff will need to discuss possible alternative options.
September 2021
This project will focus on replacing two permanent back-up generators at pump stations 23 and 25. The scope and fee for this project has been finalized and the project is expected to start in September 2021.
Project Location (369 KB)