The Pacific Northwest had lower hydropower production than historical averages in July, as warm and dry conditions prevailed in the region.
Pacific Northwest temperatures were 1 degree F to more than 6 degrees F higher than normal in July, while precipitation was below 50% of normal over nearly the entire region, according to the U.S. National Oceanic and Atmospheric Administration.
Data from the U.S. Army Corps of Engineers show that total net generation at 23 hydroelectric plants across the Pacific Northwest was 1.6% below the year-ago level and 12.7% lower than the 10-year average as it reached 5.96 million MWh. That figure is down 26.5% from June.
Year-to-date hydropower production through July totaled 54.22 million MWh, down 2.6% versus the year-ago level but up 10.0% from the 10-year average for the period.
In the upper Columbia River Basin, the Grand Coulee Dam, the largest of the region, generated 2.16 million MWh, up 1.8% versus the year-ago month but down 10.9% versus the 10-year average for the period. The Chief Joseph Dam generated 1.14 million MWh, up 1.8% versus July 2017 but down 1.5% versus the 10-year average for the month.
July flows in the lower Columbia River Basin were lower versus the year-ago period. Located on the Washington-Oregon border, the Bonneville Dam produced 204,680 MWh, down 17.0% versus July 2017 and 29.9% lower versus the 10-year average for the month. The Dalles Dam, 50 miles downstream, produced 417,448 MWh, down 4.9% from the year-ago month and down 16.3% from the 10-year average for July.