Black Canyon Dam

The canyon was named for the black basalt that choked it, and that rock made the dam site. An earlier diversion, built in 1905 upriver, left concrete canal walls still visible along the highway. Black Canyon only diverts; the water it sends out is stored upstream, behind Deadwood Dam from 1931 and Cascade Dam from 1948. In the 1970s ice jams in the backwater behind the dam flooded the valley, and the Bureau of Reclamation bought out the landowners; that ground is now a wildlife area and campground. The powerhouse carries 1925 cut in its stone.

What the plaque says

Black Canyon Dam Constructed in 1924, this $1,500,000 concrete gravity dam has a 1,039 foot crest and a 183 foot structural height. A 29 mile canal, along with lesser ditches, serves 58,250 acres of Boise and Payette valley farms. A power plant at Black Canyon Dam generates electricity for commercial use as well as for irrigation pumping. Farms far from early riverside canals benefit from this project. 377 Text prepared by the Idaho Historical Society Marker made & installed by Idaho Transportation Department

Where it stands

Worth the stop nearby

• Banks and the North Fork Payette — 19 mi
  Where the Payette's two forks meet, below fifteen miles of continuous Class V whitewater beside the highway.
• Idaho State Capitol — 25 mi
  Walls hauled from the prison quarry, heat pumped from 3,000 feet down, and its newest rooms built underground.
• Basque Block — 25 mi
  A merchant's 1864 brick house became the boardinghouse where herders from the Basque Country found beds, meals and their own language.
• Old Idaho Penitentiary — 27 mi
  A territorial prison that ran for 101 years on conditions that barely changed, and closed the year its prisoners burned it.

More markers nearby

• Freezeout Hill — 6.1 mi
• Pearl — 6.1 mi
• Horse Shoe Bend — 12 mi
• New Plymouth — 19 mi