Big Cliff Dam is at river mile 58.1 on the North Santiam River, about 45 miles southeast of Salem, Ore. It is a concrete dam with gated spillways and was completed along with Detroit Dam in 1953 at a cost of $62.7 million. Big Cliff Dam has since helped prevent more than $615 million in potential damage from floods by controlling runoff from about 438 square miles of drainage area. Because the North Santiam canyon is rocky, narrow, and steep where Big Cliff Dam was constructed, it is a concrete dam, rather than an earth and rockfill embankment structure, like other Corps dams in the Willamette Valley Project.
Big Cliff Dam is used to regulate power-generating water releases from Detroit Dam, which may cause Big Cliff Lake to fluctuate as much as 24 feet daily. Big Cliff Dam has one generator capable of producing 18 megawatts. Big Cliff's authorized primary purposes are flood risk management, power generation, water quality improvement, irrigation, fish and wildlife habitat and recreation.