Aprilhydroelectric power production surged above historical averages in the PacificNorthwest as warm weather depleted much of the region's snowpack.
Evenas the region experienced below-normal precipitation, data from the U.S. ArmyCorps of Engineers show that total net generation at 23 hydroelectric plantsacross the Pacific Northwest was 41.9% above the year-ago level and 18.4% abovethe 12-year average as it reached 8.03 million MWh. That figure is up 2.1% fromMarch.
Year-to-datehydropower production through April totaled 27.93 million MWh, down 4.6% versusthe year-ago level but up 9.9% from the 12-year average for the period.
Inthe upper Columbia River Basin, the Grand Coulee Dam, the largest of the region, generated2.05 million MWh, up 27.9% and 12.9%, respectively, versus the year-ago monthand the 12-year average for the period. The Chief Joseph Dam generated 1.18 million MWh, up25.4% and 15.2% versus April 2015 and the 12-year average for the month,respectively.
Meanwhile,April flows in the lower Columbia River Basin were higher versus historicalaverages. Located on the Washington-Oregon border, the Dam produced 497,625MWh, up 63.8% versus April 2015 and 20.8% higher versus the 12-year average forthe month. The DallesDam, 50 miles downstream, produced 750,300 MWh, up 45.7% from the year-agomonth and up 23.8% from the 12-year average for April.
Duringa May 5 presentation on the region's water supply, Northwest River ForecastCenter senior hydrologist Kevin Berghoff noted a more rapid depletion of thearea's snowpack during the month as the region experienced temperatures thatwere from 3 degrees F to more than 6 degrees F above normal. Even so, snowpackremains healthy relative to year-ago levels.
Accordingto data from the U.S. Department of Agriculture's Natural Resource ConservationService, Lower Columbia River basin snowpack on May 7 was 56% of the median,compared to a year-ago level of 6% of the median. Upper and lower Yakima Riverbasin snowpack was at 55% and 76% of the median, respectively, compared toyear-ago levels of 0% and 16% of the median. Lower Snake River basin snowpackwas 64% of the median, compared to the year-ago level of 45% of the median.
ForApril to September, the U.S. National Oceanic and Atmospheric Administrationpredicts near-normal runoff conditions across the Columbia River basin andcoastal drainages. Forecasts issued May 4 for the upper Columbia River basinproject that water supply will be 100% of normal at the Grand Coulee Dam whileat the Lower GraniteDam, water supply will be 91% of normal.