Grimes Pass Dam: Harnessing the Payette

In the late 1890s, commercial dredges began to replace the independent miners who used pans, rocker boxes, and sluices in Boise Basin. These dredges, which resembled huge floating earthmovers, scooped gold-bearing sand and gravel from the basin’s streambeds.

Steam engines, which required tremendous amounts of fuel wood, powered the first dredges in Boise Basin. Grimes and Mores Creeks were too small to generate enough electricity for a hydroelectric power plant. In 1904, a Centerville miner, Norman Gratz, built an earthen filled dam and powerhouse on the South Fork of the Payette River. He planned to sell electricity to the dredges in Boise Basin, but the dam broke before Gratz could complete his power line. Gratz sold the enterprise to W.H. Estabrook’s Boston and Idaho gold Dredging Company.

Estabrook built a 50-foot wooden dam and a power line to serve the dredges at Idaho City, Centerville, Placerville, and Quartzburg. The electricity provided to the mines helped Boise Basin recover from a slump in gold production. In 1911, Boise County regained its lead over Owhyhee County as Idaho’s largest gold producer.

In 1928, Estabrook sold the dam to the Grimes Pass Power Company. The new owners added a diesel engine to run the generator during low water periods. The powerful Payette washed out the dam in 1943. The dam was never rebuilt. Today, the South Fork flows free from its headwaters in the Sawtooth Mountains to its confluence with the North Fork at Banks.

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