Merwin Dam

Merwin Dam is a concrete arch gravity type hydroelectric dam on the Lewis River in the state of Washington. Since 1931 the dam had been blocking 117 miles of salmon and steelhead habitat. A temporary MSE wall was proposed as a part of this project, to provide an elevated crane working pad necessary for the construction of the proposed fish friendly detour.

Initially, a geogrid wall was proposed but the high crane loading did not allow the weaker geogrid material to be used.

The solution was a Hilfiker Welded Wire Wall. It was as tall as 24' and burdened with as much as 4,600 psf crane loading.