The new reservoir — built as part of the drought management plan for the Colorado River basin — passed its recent month-long testing period and is ready to store water on a temporary basis in order to control releases to Mexico. Here’s a report from the Associated Press via the San Francisco Chronicle. From the article:
The new reservoir, known during construction as Drop 2, grew out of a 2007 drought-management plan adopted by the seven states along the Colorado River. The plan identified opportunities to add water to the river by eliminating inefficient practices that led to system losses. One of those opportunities was in the system near Yuma, where billions of gallons of water allocated to U.S. farmers but never used by them flowed into Mexico, where it could be used without counting against that country’s annual allocation.
Nevada, at the time the state most at risk of running out of water, offered to pay much of the construction tab in exchange for a share of what was conserved. As the idea developed, Arizona and California agreed to contribute money for their own shares of water. In the end, Nevada paid $115 million for 400,000 acre-feet and Arizona and California added $28.6 million each for shares of 100,000 acre-feet. The states can use the water in increments over about 20 years or leave it stored in Lake Mead to delay drought restrictions…
The reservoir itself is not that big. Full, its two basins can hold up to 8,000 acre-feet. By comparison, Canyon Lake, the smallest reservoir on the Salt River, can hold more than 57,000 acre-feet. But Brock Reservoir, named for a farmer and agricultural researcher in California’s Imperial Valley, was not built to store water long-term. On any given day, it could be the largest body of water for miles in any direction, or it could be two empty holes in the ground. It will operate most often after a rainstorm, when farmers on the lower river decide they don’t need water they had ordered several days earlier. That water, which had previously flowed south into Mexico, will now be diverted into Brock and stay there until it can be returned to the system.
More Colorado River basin coverage here.