Drought grips upper Missouri basin

Drought grips upper Missouri basin Drought refuses to loosen its grip on most of the upper Missouri River basin. The disappointing runoff from rain and melting snow continues with only 45 percent of normal runoff above Sioux City, IA in April.

"Normally, the mountain snowpack peaks around mid-April, but this year it crested in March," said Larry Cieslik, chief of the Water Management office in Omaha. It topped out in the reach above Fort Peck at 84 percent of normal on March 17 and in the reach from Fort Peck to Garrison at 75 percent of normal on March 19. "Runoff from the melting mountain snow will begin entering the Missouri River main stem reservoirs in a few weeks," said Cieslik.

"The shortage of runoff continues to make it difficult to maintain steady to rising pools during the fish spawns in the upper three reservoirs," said Cieslik. "Releases are being adjusted as necessary to accomplish that goal."

With below normal mountain snow and normal rainfall the rest of the year, the forecasted annual runoff in 17.2 million acre feet (MAF). Normal runoff in 25.2 MAF. "Under the most likely runoff scenario, the navigation season will be shortened seven weeks," said Cieslik. A final determination of the navigation season length will be made after the water-in-storage check on July 1.

Releases from Gavins Point averaged 21,600 cubic feet per second (cfs) in April, compared to a long-term average of 26,500 cfs. They were increased from 21,500 cfs to 27,000 cfs on May 1 as the interior least terns and piping plovers began their nesting season. Releases are currently being varied from 27,000 to 30,000 cfs to encourage these bird species to nest on higher elevation habitat while conserving water in the reservoirs.

System storage ended April at 39.9 MAF, down 400,000 acre feet during the month. Last year at this time it was 43.6 MAF. The amount of water in the reservoirs is more than 18 MAF below normal for this time of year.

Lewis and Clark Lake will gradually rise to elevation 1206 feet msl during May.

Fort Randall releases averaged 19,900 cfs in April. They will range from 25,000 cfs to 29,000 cfs in May as needed to maintain the level of Lewis and Clark Lake. Lake Francis Case ended April at 1354.3 feet msl. It will rise gradually to elevation 1355 feet msl during May.

Lake Oahe remained essentially steady in April, dropping less than one foot, and ending the month at elevation 1581.6 feet msl. It will fall more than three feet in May as releases from Garrison Dam are reduced and increased at Gavins Point. It will end the month 29 feet below average. The reservoir is 6 feet lower than last year at this time.

Garrison releases averaged 16,900 cfs during April, ranging from 14,000 to 20,000 cfs as necessary to adjust pool levels during the fish spawn at Lake Sakakawea and Lake Oahe. They will remain at 14,000 cfs until the interior least tern and piping plover nesting season begins in mid-May, when they will be varied from 16,000 to 19,000 cfs to encourage the birds to nest on higher elevation habitat while conserving water in Lake Sakakawea during this forage fish spawn. Lake Sakakawea fell nearly one foot in April ending the month at elevation of 1814.7 feet msl. It will remain essentially steady in May, rising less than one foot. It will end the month 22 feet below average. The reservoir is 7 feet lower than last year at this time.

Fort Peck releases average 6,800 cfs in April, ranging from 5,000 to 11,000 cfs. They will remain at 11,000 cfs in May to move water to Lake Sakakawea during the fish spawn there. Releases will be reduced to 9,000 cfs in June to provide water for irrigation below the dam. The reservoir fell less than one foot during April, ending the month at elevation of 2204.9 feet msl. It will drop less than two feet in May, ending the month 31 feet below average. Last year at this time it was 8 feet higher.

The six main stem powerplants generated 584 million kilowatt hours (kWh) of electricity in April, 80 percent of normal. The forecast for 2004 energy production is 6.8 billion kWh, compared to a normal of 10 billion kWh.

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