Wanapum Dam Crack Symptom Of Several Big Problems

By Anna King

A host of problems caused the massive crack in Wanapum Dam on the Columbia River in central Washington. That’s the news out of a Grant County utility district meeting Tuesday.

Wanapum Dam photo by Anna King.A team of over 100 engineers poured through old records for 11 weeks. They found three major problems. First, the dam’s 800-foot-long spillway section isn’t anchored to bedrock with steel.

Second, they miscalculated that the concrete mass of the dam could hold the water behind it with its sheer weight. And finally, when crews poured the concrete on that part of the dam on a hot July day in 1960, they may have got that wrong too. Thomas Stredwick is with Grant County utility district.

Thomas Stredwick: “We don’t just pour massive sections of concrete at once. There’s large cubes poured. So one of those cubes, in this specific section it might not have cured properly.”

The $61-million-dollar fix involves stitching the dam to the bedrock with steel cabling and rods.

Photo: Wanapum Dam photo by Anna King.

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