US Army Corps 1616 Capitol Avenue
of Engineers Omaha, Nebraska 68102
Release No.09-003 Date: March 6, 2009
Water Management Monthly News Release
OMAHA – With one of the three conditions met, the Army Corps of Engineers is continuing with its plan to put a pulse of water into the Missouri River later this month for the benefit of the endangered pallid sturgeon.
The other two conditions, downstream river flows and National Weather Service predictions for significant rain, will be evaluated just before the anticipated two-day peak. Timing of the pulse will correspond with the annual increases in releases from Gavins Point Dam to meet navigation targets at Sioux City, Omaha, Nebraska City and Kansas City. The water needed for the pulse will be gradually staged in Fort Randall and Gavins Point reservoirs prior to its implementation, further reducing negative impacts to storage in the three large upper reservoirs of Oahe, Garrison and Fort Peck.
“There are flow limits in place that trigger reduction or elimination of the spring pulse during high downstream flows”, said Larry Cieslik, Chief of the Water Management office here. “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” he added.
The pulse is part of the 2003 Amended Biological Opinion of the U.S. Fish and Wildlife Service. The opinion identified pulses in the spring from Gavins Point as part of the Reasonable and Prudent Alternative to avoid jeopardizing the continued existence of the endangered pallid sturgeon as required by the Endangered Species Act.
On Feb. 28, ice formation upstream of Sioux City, Iowa, resulted in Missouri River level drops of 2 to 4 feet from Sioux City to St. Joseph, Mo., as the “sag” moved downstream. Releases were increased from Gavins Point to help ensure the continued operation of downstream water intakes.
The mountain snowpack is about 93 percent of normal for this time of the year. Usually around 80% of the mountain snowpack is in place by the first of March. Despite significant accumulation in eastern North Dakota and South Dakota, the plains snowpack is below normal, making the current forecast for runoff 23.6 MAF, 95 percent of average. If the forecast verifies, the level of Oahe is forecasted to peak near 1599 feet and Garrison near 1831 feet this summer. Fort Peck is forecast to peak near 2218 feet by the end of the year. Storage in the system of reservoirs increased 1.1 million acre feet (MAF) in February, ending the month at 45.4 MAF
The 2009 Annual Operating Plan contains a detailed description of continued drought conservation measures because reservoir levels are still below normal. There will be reduced navigation support, reduced hydropower generation, and lower than desired reservoir levels.
Steady to rising reservoir levels during the spring fish spawn at the three large upper reservoirs are likely if there is normal or above normal runoff. However, continued drought conditions may not make that possible at all three. If that is the case, the Corps will set releases at Garrison Dam to result in a steady to rising pool during April and May, to the extent reasonably possible. The ability to provide such conditions depends on the volume, timing and distribution of the runoff from melting snow on the plains and in the mountains of Montana and Wyoming.
The 2009 navigation season will open at St. Louis, Mo., on April 1. Because of the below normal storage, only minimum service flow support will be provided for navigation and other downstream uses. Forecasts show that the navigation season will be shortened 0 - 30 days. The final decision on season length will be made following the storage check on July 1. Releases from the reservoirs will be increased incrementally beginning in mid-March until they reach the level necessary to provide minimum service flows. The navigation season opening dates are:
Mar 23 Sioux City, Iowa
Mar 25 Omaha, Neb.
Mar 26 Nebraska City, Neb.
Mar 28 Kansas City, Mo.
Apr 1 Mouth at St. Louis, Mo.
A series of six public meetings will be conducted next month to review the 2008 Annual Operating Plan for the six main stem reservoirs. There will be presentations on this winter’s operation, planned operations for the rest of the year and an opportunity for people to ask questions and make comments. The meetings will be held:
Apr 6 7 p.m. Fort Peck, MT Fort Peck Interpretive Center
Apr 7 1 p.m. Bismarck, ND Radisson Hotel, 605 E. Broadway Ave.
Apr 7 6 p.m. Ft. Pierre, SD AmericInn, 312 Island Drive
Apr 8 1 p.m. Jefferson City, MO Capitol Plaza Hotel, 415 W. McCarty St.
Apr 8 6 p.m. Kansas City, MO Embassy Suites, 7640 NW Tiffany Springs
Apr 9 1 p.m. Nebraska City, NE Lewis & Clark Center, 100 Valmont Drive
Gavins Point releases averaged 10,300 cubic feet per second (cfs) in February. The average is 17,400 cfs. They were temporarily increased from 10,000 cfs to 12,000 cfs early this month in response to the ice formation upstream of Sioux City. Following the cold spell, releases were gradually reduced to 9,000 cfs. Releases for the pulse later this month will coincide with the annual increase to meet minimum navigation flows. The peak will be no more than 5,000 cfs above the minimum releases for two days. This is 1,000 cfs less than full service releases that are typical when storage is near normal levels. Releases will be then reduced 1,000 cfs a day back to minimum navigation service levels.
Fort Randall releases averaged 6,000 cfs in February. They will be adjusted this month as necessary to maintain Gavins Point reservoir near its desired elevation. Fort Randall reservoir rose 6 feet during February due to hydropower production releases from Oahe Dam.
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 3 feet in February, ending at elevation 1596.1 feet msl. Releases averaged 10,600 cfs during the month and will average 11,600 cfs in March to meet power generation needs. The reservoir will rise more than 2 feet, ending near elevation 1598.4 feet msl, 2.9 feet below its normal elevation. The reservoir is currently 14.3 feet higher than it was last year at this time.
Garrison reservoir fell 0.7 feet in February, ending at elevation 1823.3 feet. Releases averaged 16,100 cfs during the month, compared to the long-term average of 24,000 cfs. The reservoir is expected to climb 1.7 feet in March, ending at 1825 feet, 7 feet below normal. It is currently 15.7 feet higher than last year at this time.
Fort Peck reservoir rose 0.5 foot in February, ending at elevation 2210.5 feet msl. Releases averaged 5,900 cfs, compared to the long-term average of 11,200 cfs. The reservoir will climb a foot in March, ending at elevation 2211.5 feet, 15.8 feet below normal. It is currently 11.7 feet higher than last year at this time.
The six main stem power plants generated 356 million kilowatt hours (kWh) of electricity in February, 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 6.5 billion kWh, compared to the average of 10 billion kWh.
# # #
View daily and forecasted reservoir and river information on the Water Management section of the Northwestern Division homepage at www.nwd.usace.army.mil.
MISSOURI RIVER MAIN STEM RESERVOIR DATA
WATER RELEASES AND ENERGY GENERATION FOR FEBRUARY
|© 2011 WaterWebster.org All rights reserved. Acceptable Use Policy | Privacy Statement Policy|