Basin 18C Drainage Improvement
Project Status
To help keep area residents informed of our construction progress, we will post project updates to this site on a regular basis. Click here to see status updates.
Project Details/Neighborhood
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SE 32nd Street and West Mercer Way
Background
Localized ponding can occur during heavy rain events along West Mercer Way, south of SE 32nd Street to the outfall. In addition to localized ponding, the high flow volumes through the pipes can potentially cause scouring of the outfall.
Description
A new catch basin will be installed at the intersection of West Mercer Way and SE 32nd Street and will be used to split the flow at this location. Some of the stormwater entering this new catch basin will be re-routed through a new pipe that will be installed along SE 32nd Street. The re-routed stormwater will flow to a second outfall that has extra capacity. The result will be reduced flow volume in the existing pipes that run along West Mercer Way, reducing ponding and high flows in this pipe.
Project Timeline
Monitoring 2024
Inspection and Identification of Storm Improvements in East Seattle 2025
Design/Construction 2026-2027
Estimated Budget
TBD
Contact
Elayne Grueber, Capital Project Manager, elayne.grueber@mercerisland.gov , cell:206-549-1036
Status Updates
February 2025
The City’s consultant installed the flow monitoring equipment in late fall.
In early January, City Staff completed training on the operation and maintenance of the equipment.
Flow data has been collected for a few months and will continue to be collected through 2025. This data is critical for understanding storm flow in Subbasin 18c (along SE 32nd Street), and will play a key role in informing design decisions for upcoming stormwater improvements in the area.
These stormwater improvements in this area are scheduled for design in 2027, with construction planned for 2028.
Upon completion of the current monitoring at this location, the City will be able to deploy the equipment at additional locations to support future stormwater initiatives.
September 2024
The City has received notification from the vendor that the purchased flow monitoring equipment is expected to arrive by the end of September. Installation is planned for October, with flow monitoring set to take place throughout the fall and winter.
August 2024
The City is in the process of procuring flow monitoring equipment, with installation planned for September. Flow monitoring will occur through fall and winter.
July 2024
The installation schedule for the monitoring equipment has been adjusted. Aspect intends to install stormwater monitoring equipment at the two locations in August or early September, instead of the previously planned July timeframe. This adjustment is due to the revised availability of the consultant. The shift does not impact the overall schedule of the project as monitoring will occur in the fall with the return of the rain.
June 2024
Aspect will be installing stormwater monitoring equipment at two locations in July, one location near West Mercer Way and SE 32nd Street and the second location near SE 32nd Street and 61st Ave SE. The purpose of the monitoring equipment is to provide storm flows in downstream stormwater pipes for Subbasin 18b and 18c that will aid in decision making for potential improvements. Monitoring activities are expected to continue through the end of the year.
To optimize costs, the construction planned for this location is being combined with other storm system improvements needed in the East Seattle Neighborhood. This will result in a shift in the design and construction dates.
May 2024
As part of the design process, the City is hiring a consultant to install flow monitoring equipment in the storm pipe along SE 32nd Street to confirm current flows in the pipe. Aspect Consulting has submitted a proposal that the City is currently reviewing.
February 2024
City would like to monitor storm flow in pipes before and after project improvements. City Staff are currently working with consultant to evaluate monitoring equipment to install at the project locations for monitoring purposes.
December 2023
The design phase is nearly completed, with the consultant submitting final design plans in December for City staff review.
October 2023
Design is ongoing, with 90 percent completion by the end of October. Construction is expected to begin in Q1/Q2 2024 (following the completion of the watermain improvements along SE 32nd Street).
July 2023
CM Design Group was hired to complete the design work. Design is currently at 60 percent with final plans expected by the end of 2023.
SW0128- Project Location (1 MB)