The Bureau of Reclamation says it is conducting a �double peak� flow regime from 151.95-MW Flaming Gorge Dam through February to accommodate regional hydroelectric generation patterns and demand.
Double peak flow regimes increase water releases twice daily from the dam, on the Green River in northeastern Utah. BuRec began the regime in mid-December 2006 with morning and evening peaks reaching 1,900 cubic feet per second.
Double peak flows had been a normal mode of operation at Flaming Gorge Dam over the course of its 40-year history. However, over the past 11 years they were not scheduled due to a combination of operational considerations and dry hydrologic conditions. Under single peak operation, the peak flows reach about 1,600 cfs during daylight hours.
BuRec resumed the double peak regime at the request of the Western Area Power Administration, which proposed the change in 2005 to better match the load pattern of federal power customers. WAPA said the regime also would reduce spot market purchases the federal power marketer must make to meet customer load demands. WAPA estimates the double peak regime will save $8,500 a day over a three-month winter season versus a �single peak� regime.
Under double peak operation, the morning peak lasts three hours, and the evening peak lasts four hours. Between morning and evening peaks, releases are reduced to about 900 cfs. Releases are scheduled for 800 cfs during late evening and early morning hours, before the double peak releases. Ascending and descending ramp rates for both peaks are 800 cfs per hour. Those ramp rates were agreed to by the Flaming Gorge Working Group to provide a level of safety, and to maintain habitat in the river corridor.
Double-peak operation is consistent with BuRec’s February 2006 record of decision for meeting objectives for the Green River below the confluence of the Green and Yampa Rivers, BuRec hydrologist Rick Clayton said. (HNN 3/20/06)