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Southern Nevada Water Authority

Surplus & Shortages

Surplus & Shortages

The Department of the Interior has
guidelines and agreements to manage
surplus Colorado River water.

The elevations in Lake Powell and Lake Mead are intended to rise and fall in order to capture excess water in high flow years and to buffer against dry years (or droughts).

The Secretary of the Interior is responsible for delivering water from Lake Mead to the Lower Basin States and Mexico. Shortages and surpluses of water are based upon Lake Mead's elevation.

Interim Guidelines
In response to the severe Colorado River Basin drought conditions, the Bureau of Reclamation and the seven basin states began collaborating in 2005 on methods to share surplus and bear shortages.

In 2007, the Secretary of the Interior issued a Record of Decision for Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated
Operations for Lake Powell and Lake Mead.
The Interim Guidelines define the availability of Colorado River water for use in the lower basin based on Lake Mead’s water surface elevation.

According to the Interim Guidelines, the Secretary of the Interior would base a shortage declaration on projections of Lake Mead water levels as determined by the U. S. Bureau of Reclamation's Colorado River modeling efforts. The forecast is reviewed annually in August.

Lake Level Elevation
(above sea level)
Nevada Shortage Reduction Arizona Shortage Reduction
1,075 feet 13,000 acre feet 320,000 acre feet
1,050 feet 17,000 acre feet 400,000 acre feet
1,025 feet 20,000 acre feet 480,000 acre feet

The guidelines also created a new type of surplus called Intentionally Created Surplus. The SNWA has a number of water resources available for use under rules for Intentionally Created Surplus and other agreements.

Domestic Surplus
Under the provisions for "domestic surplus," when Lake Mead's elevation is above 1,145 feet, the Southern Nevada Water Authority will have access to an additional 100,000 acre-feet of water per year to meet customer demands.

In the future and until the Interim Guidelines expire, SNWA will use domestic surplus water when it is available and needed to meet demands.

Flood Control Surplus
The Secretary may also allocate additional water in order to control or alleviate flood potential along the Lower Colorado River.

The Water Resource Plan does not assume the availability of flood control surplus water during the planning horizon. However, the SNWA will use this resource as a priority when it is available.


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