The water level of the Green River is projected to increase by as much as two feet as officials prepare to restore normal water flows at the Howard A. Hinson Dam in the coming days. This decision follows the temporary reduction in flow that was implemented after the Desimone Levee experienced a breach in Tukwila earlier this week.
To manage the situation effectively, the U.S. Army Corps of Engineers has acknowledged the need to revert to standard outflows in order to create capacity in the reservoir. Travis Ball, the Seattle District chief of hydraulic and coastal engineering, stated, “We understand rivers are stressed with continued high flows and conditions on the ground may be changing. We’ll continue to evaluate outflows as we work to regain space in the reservoir in anticipation of the upcoming storm event this week, as well as provide downstream flood risk reduction as safely as possible.”
The anticipated increase in water flow is estimated to be around 10% to reach normal levels, according to a press release from the Corps. Engineers assessed the site of the Tukwila breach on Tuesday, finding that the temporary patch appeared to be stable.
While the situation is being monitored closely, there are ongoing concerns from county officials regarding multiple weak points in the broader levee system that may pose risks of further breaches. John Taylor, director of the King County Department of Natural Resources and Parks, mentioned, “(There are) more than a dozen, I would suspect, across the entire system, some more severe than others.”
Adding to the urgency, another levee failure on the White River led to significant flooding in the town of Pacific early Tuesday morning, resulting in the evacuation of hundreds of residents. The sustained heavy rainfall across the Pacific Northwest raises alarm bells about the potential for additional increases in river levels.
As communities prepare for a challenging weather pattern ahead, the combined efforts of engineers and local officials serve to address the risks while ensuring public safety and flood mitigation.