The Colorado River feeds Lake Mead, which is a lifeline for over 40 million people in the western United States and Mexico. Whenever a study is released showing low water levels at Lake Mead, one question flows to the forefront of a lot of people's minds: "Why are we sharing our water?" The answer is as simple: we agreed to it.
The Colorado River Compact is the complicated back story to that answer. Established in 1922 and ratified in 1944, the agreement between seven states located in the Colorado River Basin, was negotiated between the states and the federal government.
(Signing of Colorado River Compact, Photo Courtesy: Water Education Foundation)
The federal government had to get involved because initially the states could not agree on how the waters of the Colorado River Basin should be allocated among them, so the Secretary of Commerce Herbert Hoover suggested the basin be divided into an upper and lower half, with each basin having the right to develop and use 7.5 million acre-feet of river water annually, the Bureau of Land Reclamation said. This approach reserved water for future upper basin development and allowed planning and development in the lower basin to proceed.
(Upper and Lower Basin map courtesy Water Education Colorado)
The Upper Basin is for the states of Colorado, New Mexico, Utah and Wyoming. Arizona, California and Nevada were assigned to the Lower Basin.
The annual allotments in the Upper Basin were established by the Upper Colorado River Basin Compact of 1948. The Lower Basin states were given their annual allocations in 1928 as part of the Boulder Canyon Project Act, which also authorized the construction of the Hoover Dam. At the time it was called the Boulder Dam.
(Photo of Hoover Dam by Ansel Adams, 1941)
Lake Mead is a manufactured lake that came about when the Hoover Dam was built in the 1930s. It’s one of several reservoirs along the Colorado River. However, the Colorado River flow fluctuates greatly from year to year, between 4.4 million acre-feet to more than 22 million acre-feet, due to the systems storage and reservoir elevations, which are used to determine the annual operations for Lake Mead.
Projections for allocation are based on the effects of extended drought extreme temperatures, wildfires, and in some cases flooding and landslides. In 2021, the basins experienced its 22nd year of drought due to climate change, the Bureau of Reclamation said.
On Aug. 16, 2021 the federal government, prompted by the low water levels in Lake Mead, issued a water shortage declaration on the Colorado River.
The shortage will reduce the amount of water Southern Nevada will be allowed to withdraw from Lake Mead beginning in January 2022.
Bronson Mack with the Las Vegas Valley Water District says due to lake levels being low we are now being allocated 279,000 acre feet of water instead of 300,000 acre feet. The good news is that thanks to the strong water conservation efforts Southern Nevada has achieved over the last 25 years, the shortage declaration will have little impact initially. Last year we only used 255,000 acre feet, so we are already ahead of the problem.
Some of our efforts in Southern Nevada includes recycling 100% of our indoor water use.
The Colorado River Compact's existing management guidelines are set to expire in 2026, but the agreement was and remains a historic achievement because it was the first time in U.S. history that more than three states negotiated among themselves to divide and allocate the waters of a stream or river.
For more on the southwestern drought and Lake Mead's 2021 water levels, along with ways to conserve water go here.