Low runoff ends navigation season

Low runoff ends navigation season
Releases from Gavins point Dam were cut in early October, which brought the 2006 Missouri River commercial navigation season to an end, 44 days early to conserve water in the system of reservoirs. The last day of navigation was Oct. 17 at St. Louis. River stages dropped by nearly 5.7 feet at Sioux City, 5.7 feet at Omaha, 3.4 feet at Kansas City and nearly 3 feet at Hermann, MO.

"Runoff throughout the basin continues to be extraordinarily low," said Larry Cieslik, Chief of the Water Management office here. " A record-low storage of 34.7MAF was set last month, surpassing the previous record of 34.8 MAF set in January 2005. Reservoir storage is expected to remain relatively level the rest of the year."

Because of drought-depleted reservoirs, the main stem powerplants continue to produce less than normal hydropower. To make up for the generation, the Western Area Power Administration, which markets the power produced by the dams, had to purchase additional electricity to meet its contract obligations to utilities throughout the upper Midwest.

The draft 2006-07 Annual Operating Plan was published in late September. It is available on the Northwestern Division Web site at: http://www.nwd-mr.usace.army.mil/rcc/aop.html. A series of public meetings to review, discuss and take comments on the draft plan were conducted in October from Fort Peck, MT, to St. Louis MO. Comments on the draft plan will be accepted through Nov. 20.

Releases from Gavins Point Dam will average 11,700 cfs in November compared to the normal 32,400 cfs. The reservoir will remain near its current elevation of 1207.5 feet above mean sea level (msl). Releases averaged 14,600 cfs in October, compared to the long-term average of 35,500 cfs.

Fort Randall releases averages 12,400 cfs in October. They will be adjusted in November as necessary to maintain Gavins Point near its desired elevation. The fall drawdown continued throughout most of October, dropping the reservoir nearly 7 feet to 1337.6 feet. It is drawn down annually to provide storage space for winter hydropower releases and to prevent ice-related damage along the river. It will remain near its current level throughout the month.

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

Oahe reservoir rose just over a foot in October, ending at elevation 1572.6 feet msl. The reservoir is expected to rise nearly a foot in November, ending the month near elevation 1573.4 feet, 3.2 feet above its record low level of 1570.2 feet set on Aug. 30, but nearly 26 feet below its normal elevation. The reservoir is 1.3 feet lower than it was last year at this time.

Garrison releases averaged 12,100 cfs during October compared to the long-term average of 19,400 cfs. Releases will be maintained near 13,100 cfs through Nov., compared to the average of 20,400 cfs. Garrison reservoir held essentially level in October, ending the month at 1809.6 feet, and is expected to decline slightly in November, ending at 1809.3 feet. It will end the month 26.7 feet below normal. The reservoir is 4.4 feet lower than last year at this time.

Fort Peck releases averaged 5,700 cfs in October, compared to the long-term average of 8,300 cfs, and will be maintained at 7,300 cfs this month. The reservoir fell 0.2 feet in October, ending at elevation 2202.5 feet msl. It will fall 0.8 feet in November, ending the month at elevation 2201.7 feet, about 30 feet below normal. It is currently at the same level it was last year at this time. The reservoir is forecast to reach a record low of 2197.1 feet at the end of February, surpassing the previous record of 2198.3 feet set in January 2005.

The six main stem power plants generated 334 million kilowatt hours (kWh) of electricity in October, only 40 percent of normal because of lower pool levels and reduced releases from the dams. The forecast for energy production in 2006 is 6.3 billion kWh, compared to the average of 10 billion kWh.

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