Downstream of this project are the Boundary Dam,
Seven Mile Dam and
Waneta Dam. The Waneta dam is at the confluence of the Pend d'Oreille(the river changes its name as it enters Canada[which would be illegal for the rest of us to do]) and the Columbia. One mile further south the water flows back into the US, having been in Canada for only 20 or so miles.
Completed in 1956 by the
Pend Oreille Public Utilities District, this was the first hydroelectric project in the nation to be built by a PUD. Though it impounds a substantial(55 miles long) lake behind it, the Box Canyon Dam is a run-of-the-river project that was built at the exit of a narrow channel commonly known as Box Canyon. The powerhouse has four Kaplan type turbines with "
Umbrella" type generators. The project was designed with space for a fifth unit. The powerhouse is a part of the dam, with the water entering at its upper wall, then flowing through the turbines, obviating the need for exterior penstocks.
The first of four turbine-generator unit upgrades was completed in March 2011. The second turbine upgrade is scheduled for completion in 2012, and the third and fourth turbine upgrades will be done in 2013 and 2014. The new turbines are more fish friendly, with four runner blades instead of the original five. More efficient than the 50 plus year old turbines, the upgrade should increase generation capacity by approximately 18 megawatts.
The dam itself is 160 feet wide at the base and 62.4 feet high at the top of the gates. It is capable of supplying a maximum head of water of 46 feet.