Missouri River Water Management Monthly News Release February 2010

OMAHA – Significant adjustments in releases from the dams on the Missouri River were made in January due to extreme ice-forming cold temperatures and storms that downed major power transmission lines in South Dakota, North Dakota and Montana.

The heavy snowpack on the plains is creating high potential for flooding on many of the rivers in North Dakota, South Dakota, Nebraska and western Iowa. In addition, because of the large buildup of ice on the rivers, ice jams will likely add to the potential flooding issues.

“We adjust releases from each of the dams to allow downstream intakes to remain operational while avoiding conditions that cause ice-induced flooding,” said Jody Farhat, chief of the Water Management Office here. “It’s still too early to make reliable forecasts on potential flooding because so much depends on how much more snow accumulates, how fast it melts, and how much rain adds to the runoff.”

In contrast, the mountain snowpack is only 76 percent of normal for this time of the year, 80 percent of normal above Fort Peck and 72 percent in the reach between Fort Peck and Garrison, essentially the Yellowstone River basin. Traditionally, about 61 percent of the peak accumulation occurs by Feb 1.

Runoff for 2010 is currently forecast to total 28.6 million acre feet (MAF), 115 percent of normal. The 2009 total was 33.7 MAF, 136 percent of normal. “While the runoff is expected to be slightly above normal this year, the timing and distribution will be quite unusual with heavy runoff in March and April and much less in May and June,” said Farhat.

Gavins Point releases were increased in mid-January to 17,000 cfs as extremely cold temperatures produced significant ice cover downstream. They were returned to the planned winter rate of 15,000 cfs when the weather moderated. Average for the month was 15,900 cfs. The long-term average is 17,100 cfs. Releases will average 15,500 cfs through the end of February, but will be adjusted for ice conditions.

Fort Randall reservoir rose 5.8 feet last month as it received hydropower releases from Oahe and Big Bend. It ended January near elevation 1345.4 feet. It will climb about 7.6 feet in February, ending the month near elevation 1353 feet.

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

Oahe releases were cut to as low as 4,500 cfs in late January when severe storms damaged major electrical transmission lines. They were returned to normal when repairs were completed. The daily average for the month was 17,800 cfs with a rate of 15,100 cfs scheduled this month. The reservoir remained essentially level for the month ending at elevation 1607.5 feet. It will climb about 0.7 feet in February, ending near elevation 1608.2 feet. That is 8.2 feet above its normal elevation for this time of the year. The reservoir is currently 14.4 feet higher than it was last year at this time.

Garrison reservoir fell 1.4 feet in January, ending at elevation 1838.5 feet. Releases averaged 17,700 cfs. They will average 16,000 cfs in February. The reservoir will decline about 0.5 feet this month, ending at 1838 feet. That is 7.6 feet above normal for this time of the year. It is currently 14.5 feet higher than a year ago.

Fort Peck releases were sharply increased Jan. 25 to provide additional electricity when ice storms snapped major transmission lines. The higher releases ranged from 4,000 cfs to nearly 13,000 cfs. When repairs to the lines were completed, the releases were returned to the planned 4,000 cfs. They averaged 4,700 cfs for the month. Releases will be maintained at an average of 4,000 cfs until the end of February. The reservoir rose 0.7 feet in January, ending at elevation 2221.8 feet. The reservoir will rise 1.4 feet this month, ending at elevation 2223.2 feet, 3.3 feet below normal for this time of the year. It is currently 11.9 feet higher than last year at this time.

The six main stem power plants generated 558 million kilowatt hours (kWh) of electricity in January,78 percent of normal because of reduced releases from the dams. This is significantly higher than last year when generation was about 60 percent of normal. Total energy production for 2010 is forecast to be 8.2 billion kWh, compared to the average of 10 billion kWh.


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Other links of interest: 

www.mraps.org – Missouri River Authorized Purposes Study
www.moriverrecovery.org – Missouri River Recovery Program