FW schools unlikely to be affected by Green River flood

The Federal Way School District does not expect to be affected by potential flooding of the Green River Valley.

The district’s schools are all outside of the flood zone. So far, they have not been contacted by any of the districts in the flood zone who may need assistance if their schools are under water.

“We have not had communications. They have their own plans,” spokeswoman Diane Turner said. “If contacted in an event, though, we would want to do everything we could to support them.”

None of the Federal Way school buildings are located in the valley, although some are in Auburn and Kent, just not the areas that would be affected.

The district did not know if Federal Way students would be affected by flooding. “We’re always in contact with principals and staff about any concerns,” Turner said.

The school district will follow the city’s emergency plan.

“We do have a comprehensive emergency plan,” said Ray Gross, emergency management coordinator. “In the event of flooding, we would use this plan for impacts on the Federal Way area.”

Impacts could include a loss of utilities and power. A shelter is available if needed. The city’s Public Safety Committee is looking into shelter options, including the Community Center. Federal Way is working with Red Cross and the valley cities on how to help, Gross said.

The Hanson Dam, built in 1961, hugs a mound of land called the right abutment. The structure was left by a landslide. Together, the abutment and the man-made architecture restrict water flow in the Green River.

Boulders, sand, clay and a variety of materials make up the abutment, said Patricia Graesser, U.S. Army Corps of Engineers Seattle District spokeswoman. Water has naturally wound a path through the land mass since the dam’s construction, she said.

In January, the U.S. Army Corps of Engineers, which manages the dam, noticed water leaking through the abutment. The Corps became concerned the water could find a direct path through the mound, taking soil with it, and compromise the dam’s integrity. Fearing the dam’s effectiveness has been weakened, the Corps announced it will keep the reservoir behind the dam at a lower level following massive rainfalls. Larger quantities of water will flow through the river below.

The Corps installed a grout curtain along the abutment and improved drainage. However, crews are also working on a long-term repair — a subterranean concrete cut-off wall, but that will not be done for quite some time.

The damage has increased the risk of flooding in the Green River Valley, with an initial 1-in-4 likelihood. However, the Corps announced Thursday that the early fixes have dropped the odds of flooding to 1-in-25. Sandbags line the river in some places to prevent major flooding and give the levees a few extra feet.

Evacuation routes for those in the valley include several routes into Federal Way.