It’s another dry year on the Colorado River. The two-decade long drought on the river significantly lowered reservoir levels. Lake Powell is about 48 percent full, and Lake Mead, which is downstream from Lake Powell, is about 38 percent full. The federal Bureau of Reclamation believes there is a 57 percent chance of a shortfall in Lake Mead by 2020 with odds of shortages increasing in the future.
The Colorado River faces shortfalls for the foreseeable future because of a structural deficit. The users along the river and its tributaries are legally entitled to more water than the river actually carries. Original allocations that were made in 1922 were based on water flows that were abnormally high. Droughts, climate change and demand from growing cities have exacerbated the problem since then.
A shortfall will trigger mandatory cutbacks of water allotments affecting Arizona, Nevada and Mexico. California has senior and relatively secure rights, but benefits from solutions that reduce the costs of shortages for all parties. The U.S. Department of the Interior has given the seven basin states until the end of the year to complete the drought contingency plans. (Upper Basin states—Colorado, Wyoming, Utah and New Mexico. Lower Basin states—Arizona, California and Nevada).
The Upper Basin states’ drought contingency plan is designed to protect critical elevations at Lake Powell and authorize storage of conserved water in the basin. The Lower Basin states’ plan is designed to require the three states to contribute additional water to Lake Mead storage at predetermined elevations and create additional flexibility to encourage additional voluntary conservation of water to be stored in Lake Mead.
California has agreed to soften the blow by voluntarily reducing its Colorado River use by 6 percent if conditions get worse. California wants to avoid Congress or the U.S. Department of the Interior engaging and dictating a solution. If Lake Mead falls below 1,045 feet, it is very likely the federal government will take over and decide how to divide the river’s flows to keep the lake from sinking lower and approaching “dead pool” where no water could be pulled from Lake Mead.
The Colorado River supports 40 million people and 6,300 square miles of farmland in the United States and Mexico. California’s allotment serves the urban areas of Ventura to the Mexican border and farmland in the Coachella Valley, Riverside and Imperial counties.