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Yakima County Water Resources Manager Terry Keenhan walks along the old river levee along W. Powerhouse Road in Yakima on Friday. Engineers are moving a county-owned levee to reduce flooding and associated damages.

If it keeps on raining, the Ramblers Park Levee is going to break.

OK, not really. But after calculations by federal officials found the Naches River has risen by as much as 5 feet since 1974, the county has begun to move the levee farther inland to protect the area from flooding. The levee runs along the bank of the Naches River parallel to a section of U.S. Highway 12, between West Powerhouse and Pence roads.

“This will provide a lot more safety,” said Terry Keenhan, water resource manager for Yakima County. “This is a massive step in the right direction. It will reduce damages for everybody for all flood events.”

A levee is an elongated wall built along a body of water to contain rising waters during floods. Levees can form naturally, but are typically man-made. Measuring about 3,000 feet long and 10 feet tall on the river side, the Ramblers Park Levee is a bulwark of rocks and compact soil. Its oldest portion was built in 1948.

Moving the levee back is just one part of a larger, seven-phase project to protect the area. Apart from infrastructure, the area includes several homes and businesses. Preparation for the project began in 1998, when the county bought and demolished 10 houses in the area. Preparation continued in 2006, when the county moved West Powerhouse Road several hundred feet east.

The first official phase of the project began in 2012. At that time, workers moved the lower half of the levee inland. In the second phase, which started this month, crews are tasked with moving the remaining half of the levee. To do so, they’ll break the levee apart and — reusing the debris — rebuild it several yards inland.

After the entire levee is moved back, Keenhan said the Naches River will reoccupy an additional 24 acres as it moves through that area.

The second phase of the project also involves relocating Weber’s Auto Parts, a wrecking yard that originally rested fewer than 30 yards from the Naches River. After it’s been moved, the levee will run through what used to be the center of the wrecking yard. The county purchased a swath of land to the northeast so the business could move.

Work to be done in the other five phases includes replacing the nearby Nelson Dam and digging channels in front of where the upper half of the levee will be once it’s been moved. Keenhan said those channels help disperse water and keep pressure off of the levee.

“What we’re doing by putting these channels upstream is creating a natural outlet for the rise in water surface,” he said. “In other words, it’s like punching a hole in the balloon.”

Including preparation, the entire project will cost just under $30 million. Keenhan said most of the funding comes from federal and state grants. Funding for the second phase comes from Floodplanes by Design, a partnership of local, state, federal and private organizations that work to improve floodplain areas in Washington.

Keenhan predicts the entire project will be finished in the next two to three years.

Since its construction, the levee has failed to contain rising waters during several floods. The worst was in 1996, when water from the river spilled over the levee and flooded the area, destroying several homes and businesses and doing significant damage to Nelson Dam and the Powerhouse Road Bridge.

“It caused unprecedented damages at this location,” Keenhan said.

Back when the levee was first constructed, developers didn’t know as much about flooding as they do today. Keenhan blames the levee’s repeated failure on that lack of knowledge.

“We put too much infrastructure too close to the river,” he said. “We did it by design with lack of awareness about what the impacts were. There was no 100-year flood mapping or hydraulic models back in those days. Now, we model everything to assess what the risk is. Back then, we had no idea about the risk we were taking, and that’s nationwide.”