Drought maintains grip on Missouri basin Drought maintained its grip on the Missouri River basin throughout 2002. Lack of snow in the mountains and below normal precipitation produced only 64 percent of normal runoff. Above Sioux City, IA, runoff totaled 16 million acre-feet (MAF).
"System storage peaked in July at 48.9 MAF rather than the normal 62 MAF. The navigation service level started the season at 4,000 cubic feet per second (cfs) below full service. To further conserve water in the reservoirs, it was cut to minimum service on July 1," said Larry Cieslik, chief of the Missouri River Basin Water Management Division in Omaha. "The 2002 runoff was the 10th lowest runoff since 1898."
As part of continued conservation measures, winter releases from Gavins Point Dam were set at 13,000 cfs on Nov. 28. "We will continue to monitor weather and river conditions to assure adequate water supply along the river," said Cieslik.
System storage ended December at 42.7 MAF, down 400,000 acre feet during the month. Last year at this time it was 48.9 MAF. "Drought has cut the amount of water in the reservoirs to nearly 13 MAF below average," said Cieslik.
As of Jan. 2, the mountain snowpack was 58 percent of normal in the reach above Fort Peck and 74 percent in the reach from Fort Peck to Garrison. "With below normal mountain snow and normal precipitation the rest of the year, we are forecasting annual runoff to be 20 MAF," said Cieslik. Normal is 25.2 MAF.
Support for the 2003 navigation season will begin on April 1 at the mouth near St. Louis. Flow support will be at minimum service levels.
Hydropower for 2002 totaled 7.5 billion kilowatt hours (kWh) compared to a normal of
10.2 billion kWh. The six main stem powerplants generated 512 million kWh of electricity in December, 69 percent of normal.
Lewis and Clark Lake, which is near elevation 1207 feet above mean sea level (msl), will
gradually rise to 1207.5 feet msl during January where it will remain through the winter.
Fort Randall releases averaged 10,800 cfs in December. They will range from 10,000 to
12,000 cfs as needed to maintain the level of Lewis and Clark Lake. Lake Francis Case ended the month at elevation 1342 feet msl. It will continue to refill in January, ending the month near 1346 feet msl.
Lake Oahe rose more than one foot during December, ending the month at elevation 1584.8 feet msl. It will climb less than two feet during January, ending the month 16 feet below normal. The lake is 13 feet lower than last year at this time.
Garrison releases averaged 19,600 cfs during December. They were reduced to 18,000 cfs during cold weather events in late December and early January. Releases will be gradually increasing to 21,000 cfs during January if river ice conditions permit.
Lake Sakakawea ended December at 1822.5 feet msl. It will drop two feet in January, ending the month 14 feet below normal. The lake is 7 feet lower than last year at this time.
Fort Peck releases averaged 9,900 cfs during December. They will remain at that rate during January. The lake ended the month at elevation 2214.6 feet msl. It will drop nearly two feet during January, ending the month 19 feet below normal. Last year at this time it was five feet higher.