Sewer Pump Station Condition Assessment
Project Status
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Project Details/Neighborhood
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7697 W Mercer Way (PS 19); 8790 85th Ave. SE (PS 20); 8000 Avalon Dr. (PS 21); 6223 E Mercer Way (PS 22); 5406 96th Ave SE (PS 23)
Background
Mercer Island’s sewer system was constructed in the 1950s and 1960s. Since then, 3 pump stations have undergone substantial upgrades with two occurring within the last 12 years and one starting construction soon. The other 15 pump stations have undergone less significant upgrades including pump replacements over the past 20-30 years. Rehabilitation or replacement (R/R) at these pump stations is imminent.
Description
Using a phased approach, pump stations 19, 20, 21, 22, and 23 will be the first stations to receive a comprehensive condition assessment and prioritized plan for repairs/rehabilitation.
Project Timeline
Planning/Design (Q2 of 2021 – Q3 of 2023)
Project Completion (Q3 of 2023)
Estimated Budget
$200,000
Contact
Christopher Marks, City of Mercer Island Utilities Engineer: chris.marks@mercerisland.gov
Status Updates
January 17, 2024
In December 2023, the City received RH2 Engineering’s 100% submittal of the sewer pump station condition assessment, which identifies defects and deficiencies, prioritizes improvements, and assigns a rank to sewer pump stations 19, 20, 21, 22, and 23. It will be a vital tool in the planning of future capital improvement projects. City staff convened early this week to review the assessment and will return one last round of comments to the consultant for incorporation into the final report.
Week of October 30th 2023
Photo 1: Each station has two levels, grate level and pump level. Pump level (bottom level) is almost 20 feet below the surface.
Photo 2: PumpTech performs vibration analysis of the sewer pumps and motors during operation.
Last week the City’s consultant (RH2 Engineering) and their subcontractor (PumpTech) performed final data collection at City sewer lift stations 19, 20, 21, 22, and 23. The project team inspected the structural condition of the station’s vault walls, ladders, and grating; noted deficiencies in lighting, ventilation, and safety equipment; and tested the operation of all electrical control panels, valves, pumps and motors. The results of the site evaluations will be included in RH2’s final pump station condition assessment which is expected to be received for comment in December 2023.
October 2023
RH2 Engineering will be out this week to continue evaluating pump stations 19, 22, and 23. The site visits are expected to be completed by the end of October, at which point they will have all the observations and data needed to deliver the final report.
July 2023
RH2 Engineering delivered the preliminary draft assessment of pump stations 20 and 21 on July 6th. The City reviewed and returned comments to the contractor on July 29th. RH2 Engineering will use the City’s comments to refine the scope of their evaluations to ensure the City’s objectives are met. Installation of the previously approved temporary flow meters at all sites, and evaluations of pump stations 19, 22, and 23, is tentatively scheduled for the latter part of August.
June 2023
The engineering consultant has recommended the installation of temporary flow meters at the pump station sites to confirm the pumping rates calculated during prior site visits. Additional site visits and a review of the preliminary draft assessment are expected to take place in early July.
May 2022
City staff met with the Consultant, RH2 Engineering, where they provided a preliminary overview of their findings at the two pump stations. RH2 will start working on the draft assessment report for these two sites in the next couple of months.
April 2022
Photo 1: Data logger installed on pump
Photo 2: Consultant measuring elevation at associated pump station manhole
Photo 3: Consultants looking down into pump station
RH2 Engineering came out in February to install temporary data loggers at the five pump stations and recorded good wet-weather flow data. Condition assessments for two pump stations were also completed in February. RH2 is reviewing information from the data loggers and their site visit and will provide an update at a meeting later in April.
February 2022
A contract was executed with RH2 Engineering in December and the kick-off meeting occurred the first week in January. The first two station assessments are expected to occur in February with an evaluation to follow before continuing with the remaining sites.
November 2021
Photo 1: Consultant's data logger
Photo 2: Hand valve on pump
Contract negotiations with RH2 continue. As part of the assessment, the City wants to have flow capacity evaluated for each pump station. This can be accomplished by temporarily installing the consultant’s data loggers on each pump’s hand valve.
The City received the revised scope and fee from the consultant in November and a contract is expected to start later in December.
SU0117 Project Location (807 KB)