BISMARCK, N.D. (AP) — Electric power generation from the Missouri River's six upstream dams fell far below average in 2013, as water was kept in reservoirs to make up for a dry 2012, according to the U.S. Army Corps of Engineers.
The Corps, which manages dams and reservoirs along the 2,341-mile river, said energy production from the dams in the Dakotas, Montana and Nebraska totaled 7.6 billion kilowatts of electricity last year, down from 10.4 billion kilowatts in 2012.
The plants have generated an average of 9.4 billion kilowatt hours of electricity since 1967, including a high of 14.6 billion kilowatts in 1997, said Mike Swenson, a corps engineer in Omaha, Neb.
The Western Area Power Administration, which buys and sells power from 55 hydropower plants around the nation, says the six Missouri River dams are WAPA's second-largest producer of energy.
Randy Wilkerson, a WAPA spokesman in Lakewood, Colo., said the shortfall in electricity production from hydropower meant WAPA had to get energy from other, more expensive sources. The supplemental energy cost an additional $126 million for the fiscal year that ended in September, he said.
WAPA has spent more than $1.5 billion since 2000 to fulfill contracts due to shallow river levels caused by drought.
"It's not unusual," Wilkerson said of the shortfall in energy production last year.
Oahe Dam near Pierre, S.D., which holds Lake Oahe in the Dakotas, and Garrison Dam, which creates Lake Sakakawea in western North Dakota, are typically the biggest power producers in the Missouri River system.
Oahe Dam generated 1.9 billion kilowatt hours last year, below the long-term average of 2.6 billion kilowatt hours, data show. The dam recorded a low of 1.1 billion kilowatt hours in 2007.
Garrison Dam also generated 1.9 billion kilowatt hours of electricity last year, data show. The long-term average at the dam is 2.2 billion kilowatt hours.
Swenson said 2013 was about average for rain and snow runoff in the Missouri River system, though the reservoirs are still recovering from a below-average year for moisture in 2012. Energy production from the six upstream dams totaled 11.1 billion kilowatts of electricity in 2011 and the highest in more than a decade.
The Corps is charged with finding a balance between upstream states, which want water held in reservoirs to support fish reproduction and recreation, and downstream states, which want more water released from the dams, mainly to support barge traffic.
Swenson said more water was released from upstream reservoirs in 2012 than in 2013 to meet "downstream targets." In doing so, more water ran through turbines, creating more electricity than in 2013, when the water was held to replenish the reservoirs.
The water storage level of the six upstream reservoirs in the Missouri River system is about 50 million acre-feet at present, about 6 million acre-feet below the ideal level, said Joel Knofczynski, a corps hydraulic engineer. An acre-foot is the amount of water covering one acre, a foot deep.
Based on runoff estimates for 2014, the Corps has forecast 8.4 billion kilowatt hours of electricity this year, and a billion kilowatt hours below the long-term average.
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