Reservoir levels are dropping throughout the West, as the drought tightens its grip on the region and intense summer heat further stresses both water supply and the surrounding landscape. Many reservoirs are at or approaching historic low levels due to lackluster rainy seasons combined with increasing temperatures due to climate change.
The drought crisis is perhaps most apparent in the Colorado River basin, which saw one of its driest years on record, following two decades of less-than-adequate flows. The nation’s largest reservoir, Lake Mead near Las Vegas, is at its lowest level since the lake filled after the construction of the Hoover dam in the 1930s; it currently sits at 1,069 feet above sea level, or 35 percent of its total capacity. It supplies water to Arizona, Nevada, California, and Mexico.
Further upstream, Lake Powell, which feeds Lake Mead, is at only 34 percent of its total capacity. By next spring, Lake Powell is projected to hit its lowest level since it was filled in 1964, possibly jeopardizing its ability to generate power. California’s two largest reservoirs, Lake Shasta and Lake Oroville, are on track for potential record lows this summer, now at 37 percent and 31 percent of their total capacities, respectively.
Amid a warm spring and early-season heat, mountain snowpack never made it into rivers and reservoirs — it simply seeped into bone-dry soils or sublimated directly into the atmosphere. This kind of reduced runoff “efficiency” is expected in a warming climate, and it contributed to the quickly intensifying drought this year in California and other states. READ MORE