Public Meeting:
SPU will be holding a public meeting on Wednesday, October 19, in the Fellowship Hall of Luther Memorial Lutheran Church, at 13047 Greenwood Avenue N. There will be an Open House from 6:00-6:30, followed by a meeting from 6:30-8:00. SPU will be sending out meeting invitations to the community at large as they did for the April 6th meeting. This meeting will provide additional information on the two pilot projects and the sewer and stormwater improvements discussed below.
Infiltration Reduction Pilot:
95% of candidates in SPU’s Infiltration Reduction pilot area chose to participate in the program. Over the summer, the mainline sewer pipes and side sewers in this area have been inspected and cleaned, and clean-outs have been installed in side sewers that didn’t have them previously. Grouting of mainlines and side sewers will be completed by the end of September. Early indications are that the grouting has been very successful in reducing infiltration.
Backflow Prevention Pilot:
To date, 83% of potential candidates for backflow valves have allowed SPU to conduct basement elevation surveys of their homes, and the survey data is now being used to update our Broadview sewer system modeling. This modeling is critical to determining not just which homes would benefit from the installation of a backflow valve, but will guide us in our decisions regarding how to proceed with long-term sewer improvements. The next step in finalizing the list of eligible homes is to video side sewers to determine exact locations of side sewer pipes, to examine connections and groundwater issues, to decide the best type of device to install, and to locate the best spot for the devices. We hope to finalize our list of eligible homes by the end of September and begin installing valves in October.
Broadview Sewer and Stormwater Improvements Project:
Earlier this summer, SPU put out a full Request for Proposal (RFP) for a consultant for the Broadview Sewer and Stormwater Improvements Project. The engineering and support services will include public involvement, alternatives analysis, preliminary engineering, permitting, and design through construction support. Given the issues in Broadview, it is anticipated there will be multiple improvements to the sewer and stormwater system over multiple years. At this time, proposals from the top three teams have been reviewed and we expect to make a selection by the week of September 20th. After the selection, the Program Manager will work with the selected consultant team on a detailed scope of work, which is expected to take approximately 4-5 weeks.
Broadview Modeling and Flow Monitoring:
Key to the Broadview Sewer and Stormwater Improvements Project, SPU is in the process of selecting sites for additional flow monitoring of the Sanitary Sewer and Storm Drainage system. The flow monitoring data is used to determine the real-time hydraulic conditions of conveyance systems under various conditions. Flow monitoring can also be used to determine inflow/infiltration levels, calibrate dynamic hydraulic computer models, and measure capacity within the system. The calibrated computer models allow engineers to predict flow patterns within the existing system, as well as predict how changes to the system will affect flows throughout the basin.
SPU and its consultants will be in the field over the next month inspecting potential flow monitoring sites as well as installing meters. They will also be out in the basin during the fall and winter to inspect the monitoring equipment, collect data from the equipment, and perform field observations of surface flow patterns.
The drainage system flow monitors will have above-ground enclosures adjacent to the monitoring equipment. To ensure the success of the Broadview flow monitoring effort, SPU needs the assistance of the Broadview Neighborhood. If you see any of the following, please contact us at spu_broadviewprojects@seattle.gov:
• Any vandalized enclosures
• Anyone tampering with the enclosures
• Debris built up in front of or behind the flow monitors and/or the weir structures
• Loose equipment and/or wire bands floating in the drainage system.
Venema Creek Natural Drainage System (Green Stormwater Infrastructure) Project:
SPU is currently evaluating the performance and costs of the project design alternatives, based on recently furnished infiltration field test results and geotechnical investigation.
Pipers Creek Flow Control Study:
Over the next two years, SPU will be conducting a flow control study in Piper’s Creek to examine the amount of stormwater coming from different drainage areas in the creek watershed. The project objective is to identify high priority stormwater management areas and actions in the Piper’s Creek watershed to reduce the impacts of stormwater runoff on Piper’s Creek.
Please let me know if you have any questions.
Sincerely,
Celeste Duncan
Community Relations, SPU
(206) 684-8527, celeste.duncan@seattle.gov
