The latest runoff projections for the Missouri River system, including North Dakota's Lake Sakakawea, show little change from one month ago.
The amount of snow that falls in portions of the Rocky Mountains and western Montana during the winter is generally responsible for the greatest influence in Missouri and Yellowstone River runoff that eventually reaches Lake Sakakawea. The amount of runoff that entered the Missouri River basin in 2012 is expected to total 19.7 million acre feet of water. That amount is substantially lower than the long-term average of 24.8 maf.
Lake Sakakawea's elevation Thursday was 1,830.3 feet. The latest forecast supplied by the U.S. Army Corps of Engineers projects an end of year elevation of 1,829.7 for Sakakawea, a scant two-tenths lower that what was projected in early November. Looking ahead, Lake Sakakawea is forecast to drop to 1,828.5 feet by Jan. 31, 2013, and 1,827.7 feet by Feb. 28, 2013. Lake Sakakawea surpassed spillway level of 1,854 feet during 2011.
Elevation forecasts can be expected to change significantly as spring approaches and more information about snowpack and ground moisture becomes known. Nationally the trend has been drought conditions, particularly in the lower reaches of the Missouri River below Lake Sakakawea. Nebraska and Oklahoma are said to be experiencing their driest conditions in 150 years over much of both states. Missouri has been lobbying for the Corps to release water from Upper Missouri reservoirs to alleviate declining water levels in the Mississippi River. To date, the Corps has declined the request, citing the need to conserve water in the event that the drought continues into 2013.
While Lake Sakakawea's current and projected elevations are somewhat low, they are not necessarily out of the norm for the season. However, less than normal runoff next spring would likely lead to less than desired levels in the Missouri River system's three upper reservoirs - Fort Peck in Montana, Lake Sakakawea in North Dakota and Lake Oahe in North and South Dakota.
The Climate Prediction Center is calling for "above average" snowfall over the Montana portion of the Missouri River basin in December. However, the CPC rates the region as having an "equal" chance of normal snowfall through March. Historically, the majority of snowfall in the Rocky Mountains falls late in the season. Therefore, the March 1, 2013, runoff outlook will be considered one of the most important forecasts to be issued in the months ahead.