May 2009 Water Management News Release

OMAHA – Storage in the Missouri River main stem reservoirs has significantly increased over the past year, enabling plans to move forward to put a pulse of water into the river this month to benefit the endangered pallid sturgeon.

With storage far exceeding the minimum required for the pulse, other components that go into the decision to conduct it are downstream river conditions, water temperature, and nesting activity by the protected least terns and piping plovers. The pulse must be initiated by May 19.

There are flow limits in place that trigger reduction or elimination of the spring pulse during high downstream flows. An additional safeguard is the use of observed and anticipated rainfall into the Corps’ daily river forecast to provide greater assurance that flows will remain below the limits. River levels above these flow limits coupled with forecasts from the National Weather Service for additional rain resulted in the elimination of the pulse planned for March.

“The runoff from melting snow and ice put 4 million acre feet (MAF) of water into the reservoirs in April,” said Jody Farhat, Chief of the Water Management office here. “The levels of the big reservoirs of Oahe, Garrison and Fort Peck have risen 9 feet, 4 feet and 2 feet respectively in just one month,” she added.

The current forecast for runoff is 31.5 MAF, 127 percent of average. If the forecast verifies, the level of Oahe will peak near 1614 feet and Garrison near 1839 feet this summer. Fort Peck is forecast to peak near 2222 feet by the end of the year. Storage in the system of reservoirs ended the month at 53.3 MAF and is forecast to peak at 56.5 MAF in June. That last time it was at this level was in 2000.

The 2009 navigation season opened at St. Louis, Mo., on April 1. Minimum service flow support will be provided until July 1 for navigation and other downstream uses. Forecasts show that the navigation season will most likely not be shortened this year. The final decision on season length and flow support for the second half of the navigation season will be made following the storage check on July 1.

Gavins Point releases averaged 17,000 cubic feet per second (cfs) in April. The average is 25,300 cfs. Releases will average 21,000 cfs in May.

Fort Randall releases averaged 12,700 cfs in April. They will be adjusted this month as necessary to maintain Gavins Point reservoir near its desired elevation. Fort Randall reservoir rose 2.6 feet during April. It will end May at elevation 1355.2 feet.

Big Bend reservoir will remain in its normal range of 1420 to 1421 feet. Releases will be adjusted to meet hydropower needs.

Oahe reservoir climbed almost 9 feet in April, ending at elevation 1612.5 feet msl. Releases averaged 12,000 cfs during the month and will average 9,900 cfs in May to meet power generation needs. The reservoir will rise nearly 2 feet, ending near elevation 1614.3 feet msl, 10.1 feet above its normal elevation. The reservoir is currently 5 feet into the flood pool and is 29.4 feet higher than it was last year at this time.

Garrison reservoir rose 4 feet in April, ending at elevation 1830.1 feet. Releases averaged 9,000 cfs during the month, compared to the long-term average of 19,000 cfs. The lower rate is due to sharply reduced releases to prevent flooding in the Bismarck/Mandan area from large tributary river flows. The reservoir is expected to climb just over 2 feet in May, ending at 1832.4 feet, 1.5 feet below normal. It is currently 22.8 feet higher than last year at this time.

Fort Peck reservoir rose just over 2 feet in April, ending at elevation 2214.2 feet msl. Releases averaged 4,100 cfs, compared to the long-term average of 7,500 cfs. The reservoir will climb 1.4 feet in May, ending at elevation 2215.6 feet, 14.6 feet below normal. It is currently 15.4 feet higher than last year at this time.

The six main stem power plants generated 390 million kilowatt hours (kWh) of electricity in April, only 56 percent of normal because of lower pool levels and reduced releases from the dams. Total energy production for 2009 is forecast to total 7 billion kWh, compared to the average of 10 billion kWh.