Sewer and Stormwater Improvements
Goals
- Reduce sewer backups in homes
- Reduce sewer backups in streets
- Reduce flooding related to public health and safety
- Maintain or improve current flow control to creeks
- Determine and implement the best solutions to meet these goals, ones that are cost-effective, supported by the majority of the community and meet SPU’s environmental objectives
Project
The larger project is now underway. It will focus on all of the above-mentioned goals for areas in Broadview that have been identified as locations where the levels of service for sewer and stormwater systems could be improved. This project will take a number of years to complete, though the work may occur in phases.
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.
Pilots
Key to helping us decide what long-term solutions we want to propose, SPU is currently conducting two pilots in Broadview, the Infiltration Reduction Pilot and the Backflow Valve Pilot.
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