South Park Flooding

On December 27, 2022, the Duwamish River flooded a South Park neighborhood, damaging local homes and businesses. The flooding was caused by a combination of factors including higher-than-average tides, rain runoff, and melting snow. This area has faced prior flooding, as well as environmental and health challenges due to historical inequities and industrial contamination.

The City Responded:

• The City partnered with local community groups and disaster relief organizations to provide assistance to impacted residents.
• The immediate response with partners was to provide food assistance, hotel vouchers, pumps, clean-up equipment, and other supplies.
• Once immediate needs were addressed, the City and partners began to assist with clean-up efforts, safety inspections of impacted properties, and finding long-term housing support for families who need it.
• Community partners included Duwamish River Community Coalition, Just Health Action, Khmer Community of Seattle King County, Villa Communitaria, Cultivate South Park, and SeaMar Community Health.
• Disaster relief partners included the Red Cross, Team Rubicon, King County Office of Emergency Management, and Public Health – Seattle & King County.
• City agencies involved Seattle Public Utilities, Human Services Department, Office of Emergency Management, and Department of Construction & Inspections, with support from the Mayor’s Office, Office of Sustainability and Environment, Facilities and Administrative Services, and others.

Seattle Public Utilities has invested in flooding mitigation projects and initiatives, and flood response activities including:

1. Grinder Pumps: This SPU and King County project has installed 22 grinder pumps in homes most at risk for sewer backups.
2. South Park Pump Station.  This facility is now operational, and will help reduce flooding in northeast South Park by enabling drainage pipes to flow into the Duwamish River during high tide. It will reduce right-of-way flooding during many (but not all) high tide events in locations where we have drainage infrastructure.
3. South Park Roadway and Drainage Project, Phase 1.  This SPU and SDOT project installed ten blocks of new roadway and drainage pipes within the industrial area, connecting those areas to the pump station. Sidewalk and landscape improvements were also included on some blocks. This project was largely funded by the King County Flood Control District.

SPU is leading and/or participating in multiple near-term infrastructure investments in South Park including:

1. South Park Roadway and Drainage Project, Phase 2. This project will install pipes to expand the footprint and the number of blocks served by the pump station.  Included blocks and improvements have not yet been finalized. It is in the planning phase and working to secure additional external funding. (internal note: Anticipated approx. $18-$24M investment.)
2. South Park Stormwater Quality Facility.  This project will treat stormwater before it flows to the Duwamish River. It is in the planning phase and is working to acquire land that may meet community river access priorities and would require contaminated site cleanup. Anticipated to be constructed by the end of 2030 but that the schedule for completion may change given that the project is in the planning phase (internal note: Anticipated approx. $60M investment.) 
3. King County Wastewater Treatment Division’s (WTD) Sewer Capacity Long-term Planning. SPU is participating is this work which is evaluating long-term approaches to prevent wastewater backups throughout South Park.

SPU is also working with several City departments on climate adaptation and long-term resilience in the Duwamish Valley. To protect South Park from flooding, there needs to be both drainage/sewer improvements and climate adaptation improvements.