PORTLAND, OR -
The U.S. Army Corps of Engineers continues to monitor snowpack levels across the Columbia River Basin. “Currently, levels are well below normal for this time of year, so we’re seeing lower than normal river flows throughout the system,” said Steve Barton, Chief of the Corps’ Water Management Division. Basin snow below 5,000 feet in the United States is either already gone or is melting ahead of normal.
Canada snowpack in the Upper Columbia River Basin, however, remains closer to normal levels. The Northwest River Forecast Center is estimating the Kootenay River water supply upstream of Libby Dam in Montana to be 79 percent of normal. Forecasts for runoff from the rest of the basin into the river system continue to decline, with current projections for The Dalles Dam water supply, April through August, at only 69 percent of normal. Snake River projections for Lower Granite Dam water supply is 51 percent of average, while forecast water supply into Libby Reservoir, is approximately 79 percent of normal.
Peak flows on the Columbia and Snake rivers have already occurred, peaking at a little over 220,000 cubic feet per second during April at The Dalles Dam. Low flow conditions are expected to persist through the rest of the summer, in particular due to early snow melt and warmer than average temperatures over the winter and into the spring.
Water supply forecasts for flows on the lower Snake River are also projected to be low. Projections for water flow on the Snake River as measured at Ice Harbor Dam are 26,000 cfs during July and August.
For the lower Columbia River, flow projections could be about 135,000 cfs during July and 120,000 cfs during August and September, which places the basin in the bottom 10% of driest water years.
“While the forecasts may seem bleak,” said Barton, “we are committed to using best engineering practices to manage and operate the dams and reservoirs of the Columbia River system to meet all of our authorized purposes.”
More information about basin forecasts can be found on the Northwest River Forecast Center’s web pages:
Current Snow Conditions: http://www.nwrfc.noaa.gov/snow/
Precipitation Map: http://www.nwrfc.noaa.gov/rfc/
The Dalles: http://www.nwrfc.noaa.gov/water_supply/ws_forecasts.php?id=TDAO3
Lower Granite: http://www.nwrfc.noaa.gov/water_supply/ws_forecasts.php?id=LGDW1
Snake River: Lower Granite: http://www.nwrfc.noaa.gov/stp/station/stpplot/stpplot.cgi?LGDW1
Columbia River: The Dalles: http://www.nwrfc.noaa.gov/stp/station/stpplot/stpplot.cgi?TDAO3