The PUD operates the Calispell Creek Pumping Plant that is located about 30 miles upstream of Box Canyon Dam near the mouth of Calispell Creek, a tributary of the Pend Oreille River. The Calispell Creek Pumping Plant is regulated by the Federal Energy Regulatory Commission under the Box Canyon Hydroelectric License, FERC No. 2042. The pumping plant was originally constructed in the early 1900s to prevent flooding of agricultural lands along the Pend Oreille River. The plant pumps water from Calispell Creek over a railroad dike (near the mouth of the creek) into the Box Canyon reservoir.
The pumping plant consists of two pump stations with six pumps and a total hydraulic capacity of 530 cfs. Operation of the pumping plant allows the PUD to maintain a higher reservoir elevation for the project and thus produce more power.
The pumps are operated under an agreement (Plan E) between the PUD and Diking District No. 2 of Pend Oreille County. Plan E provides for the plant to be operated in high-flow conditions in a manner that approximates flow conditions in Calispell Creek that existed prior to the construction of Box Canyon Dam. This ensures that water levels in Calispell Creek do not exceed water levels in the reservoir under the current backwater constraint at Albeni Falls Dam, thus preventing flooding of lands near Calispell Creek.