Seattle's South Park receives long-awaited stormwater drainage upgrades to combat flooding

SEATTLE — Seattle Public Utilities (SPU) and the King County Wastewater Treatment Division have finished the long-awaited infrastructure work to improve stormwater drainage in South Park. It's meant to prevent the devastating flooding and sewer backups that happened during the king tides for years,most recently in late 2022.

Flooding prevention is top of mind for many in South Park with a king tide expected next week.

City and county officials walked KOMO News through the upgrades Tuesday that are meant to prevent future flooding.

“Mother Nature always has surprises in store and we’ve done the best we could with the knowledge that we have,” SPU Deputy Director Ellen Stewart explained. “We’ve surveilled the river, we’ve taken the information that we have from last year’s event, we’ve added a contingency factor onto that.”

There are 106,000 sandbags stretched across a mile and a half at the Duwamish River’s edge to help resist the pressure of the river during high tide.

Grinder pumps were installed in 24 flood-prone homes to prevent sewer backups.

King County Wastewater Treatment Division Director Kamuron Gurol addressed upgrades to the regulator station that helps manage the flow of wastewater through the King County system.

"Both stormwater and wastewater flow through the system. This station helps us manage that to make sure that it can flow evenly and get to the treatment plant so it can be treated properly," Gurol explained. "In very heavy rainfall events, the regulator is set at a certain point so that flow can get through there, and we’ve modified those settings so we can get a little more flow through that."

Jill Reese said her basement and backyard were underwater last December, had an estimated $60,000 in water damage, and the city paid to rebuild the basement. She is hopeful the new grinder pump in her backyard will stop sewer backups, but she still worries about the river toppling over.

“We’re really appreciative of what the city is doing to try and prevent another catastrophe but you know this problem is one that’s just going to keep getting worse. Climate change is coming really quickly,” Reese said.

RELATED:Community-wide flood cleanup in South Park expected to take days

Additionally, a new pump station will operate during high tide and heavy rain to release storm water to the river to reduce flooding events. It's capable of pumping 32,000 gallons of storm water per minute.

Underground, crews installed a new public storm drain stretching one and a half miles to support about 17,000 people and 450 businesses.

RELATED:Heavy rain, king tides flood Seattle neighborhoods

City and county officials acknowledged the South Park neighborhood has been neglected for too long and said they are trying to right those wrongs.

“It’s a combination of factors. I would say it’s the planning, it’s the funding. We’ve had many funding partners on a lot of these projects,” Stewart explained. “So, as you can imagine, Seattle is a big city, a rainy city. We have a lot of competing priorities for our projects and our money so it’s just a matter of how we plan our projects and how we fund things.”