As Colorado evacuees return home after the flood, water managers along rivers downstream are watching reservoirs rise.
Last week’s epic storm started out as a low pressure center that tapped the Pacific Ocean near western Mexico, then moved northeast and hovered over Colorado when it hit a dome of high pressure. It settled over the Rocky Mountains on Sept. 11 and dropped a record nine inches of rain on Sept. 12.
The rain continued to fall on Boulder and Denver for five days straight. The resulting floods killed six people and took out 1,500 homes.
Most of the water fell onto the eastern side of the Rockies, flowing into the Pecos River and the Rio Grande in New Mexico. The flood waters combined with heavy rain over New Mexico and wreaked havoc on the drought-stricken landscape that couldn’t hold the deluge.
The Cochiti Reservoir rose almost 15 feet and the Elephant Butte Reservoir came up about eight feet.
On the west side of the Rockies, Lake Powell in northern Arizona saw levels rise two feet with the help of rain in Utah and northern Arizona.
Katrina Grantz, a hydraulic engineer for Glen Canyon Dam, said this amazing rain event is not enough to pull the Southwest out of its record drought.
“That two feet was kind of a nice bonus that we were able to put into the bank but we don’t expect the lake levels to continue rising much further,” Grantz said.
Grantz said snowpack, not rain, is the primary driver when it comes to drought relief. But if there’s a silver lining to the storm clouds, Grantz said an extreme rain event like this decreases the probability of water shortages in the Southwest in coming years.
Updated 9/19/2013 at 8:38 a.m.