Water shortages
The Colorado River Basin is experiencing the worst drought in recorded history.
Since 2000, snowfall and runoff into the basin have been well below normal. These conditions have resulted in significant water level declines at major system reservoirs, including Lake Mead and Lake Powell.
The elevation of Lake Mead has dropped about 170 feet since 2000. The Secretary of the Interior made the first-ever shortage declaration in 2021, which reduced the amount of water available to Nevada and other water users in 2022.
A tier two shortage was declared in 2022 for 2023 operations, further reducing the amount of water available to Nevada and Arizona. The risk of shortage remains high in future years.
What you can do to conserve
- ✅ Follow mandatory seasonal water restrictions to reduce outdoor water consumption—which accounts for about 60 percent of Southern Nevada's overall water use.
- ✅ Replace nonfunctional grass with drip-irrigated trees and plants through the SNWA's Water Smart Landscapes rebate program (WSL).
- ✅ Prevent and report water waste (water flowing off a property into the gutter) to local water utilities.
Current condition: Tier two water shortage
The continued decline of Lake Mead water levels prompted the federal government to declare a tier two shortage in August 2022, further limiting the amount of water Southern Nevada is allowed to withdraw from the Colorado River at Lake Mead beginning January 2023. Nevada's total obligation under the Interim Guidelines and DCP for 2023 is 25,000 acre-feet. The total obligations by all parties, including Arizona and Mexico, is 721,000 acre-feet. (An acre-foot is equal to 325,851 gallons of water.)
Nevada is not currently using its full Colorado River allocation, and near-term shortage declarations will not likely impact current customer use. By the end of 2021, Nevada's consumptive Colorado River water use was 242,000 acre-feet. This amount is below any Colorado River water supply reduction under existing rules.
In addition to the tier two shortage, the United States Department of the Interior (DOI) requested that the seven Colorado River States develop a plan by mid-August to reduce water use by 2 to 4 million acre-feet of water next year.
In a letter sent to DOI on August 15, 2022, SNWA General Manager John Entsminger acknowledged the states' inability to finalize a plan and provided recommendations for the DOI to consider as they evaluate implementing unilateral action to reduce water use. This includes expanding opportunities to increase water efficiency and incentivize conversion to low water-use crops in the agricultural sector; investing in water recycle projects; create a grass reduction program for all Colorado River users; and creating new beneficial-use criteria in the Lower Basin to eliminate wastewater and antiquated water use practices among other recommendations.
What agreements are in place?
Federal, state and municipal water providers in the Colorado River Basin have worked together for more than a decade to slow the decline of Lake Mead water levels. The 2007 Interim Guidelines for the Coordinated Operations of Lakes Mead and Powell and the 2019 Lower Basin Drought Contingency Plan (DCP) are two agreements that benefit Nevada and other Colorado River water users.
Among other things, these agreements:
- Keep more water in the river for the benefit of all water users and the environment.
- Help slow Lake Mead water level declines to preserve critical reservoir elevations.
- Allow for water banking in Lake Mead in the form of Intentionally Created Surplus.
- Draw participation from new stakeholders, including California and Mexico.
Shortage Guidelines
The Bureau of Reclamation issued detailed guidelines in 2007 that mandate how Colorado River water stored in Lake Mead is managed during a declared shortage.
Under a shortage declaration, the amount of Colorado River water available to Nevada and Arizona is reduced. The Secretary of the Interior makes a shortage declaration for the following year when the U.S. Bureau of Reclamation's model projects Lake Mead to be at or below 1,075 feet on January 1 of the following year. The model is run annually in August.
Shortage amounts vary by state and are based on Lake Mead water levels. Nevada's shortage volume ranges from 13,000 to 20,000 AFY.
Drought Contingency Plan
Congress authorized implementation of the Lower Basin Drought Contingency Plan (DCP) in 2019. Under this agreement, Lower Basin States will begin making DCP contributions when the elevation of Lake Mead is projected to be at or below 1,090 feet.
Contribution amounts vary by state and are based on Lake Mead water levels. Nevada's DCP contribution ranges from 8,000 to 10,000 AFY. This volume of water is in addition to any mandatory reductions associated with a federally declared shortage. Nevada will receive credit for its DCP contributions. These credits can be recovered when Lake Mead is above 1,110 feet. Below this elevation, Nevada can access or borrow its credits, subject to certain restrictions.
Nevada's combined maximum obligation under these agreements ranges from 8,000 to 30,000 AFY. If at any time Lake Mead is projected to fall below an elevation of 1,030 feet, the Secretary of the Interior will consult with Lower Basin stakeholders to determine if additional actions are needed to protect against the potential for a Lake Mead to decline below 1,020 feet.
In 2022, the U.S. Bureau of Reclamation’s August 24-month study projected Lake Mead’s minimum probable elevation to drop below 1,040 feet. In accordance with the DCP, the Secretary of the Interior and the Lower Basin States are actively engaged in consultation to establish additional plans and actions through 2026 to protect against Lake Mead declining below elevation 1,020 feet.
| Lake Mead water level | Shortage amount | DCP contribution | Total |
|---|---|---|---|
| Above 1,090 feet | 0 acre-feet per year | 0 acre-feet per year | 0 acre-feet per year |
| At or below 1,090 feet | 0 acre-feet per year | 8,000 acre-feet per year | 8,000 acre-feet per year |
| At or below 1,075 feet | 13,000 acre-feet per year | 8,000 acre-feet per year | 21,000 acre-feet per year |
| Below 1,050 feet | 17,000 acre-feet per year | 8,000 acre-feet per year | 25,000 acre-feet per year |
| At or below 1,045 feet | 17,000 acre-feet per year | 10,000 acre-feet per year | 27,000 acre-feet per year |
| Below 1,025 feet | 20,000 acre-feet per year | 10,000 acre-feet per year | 30,000 acre-feet per year |
Hoover Dam
Hoover Dam regulates Colorado River flows, provides water storage and produces hydroelectric power to Nevada, California and Arizona. The dam created Lake Mead, which stores Colorado River water for the lower basin states of Nevada, California, Arizona and the country of Mexico. Each of the Lower Basin states receives an annual allocation of Colorado River water as detailed in the Boulder Canyon Project Act.
Lake Mead can hold almost 9 trillion gallons of water. However, due to ongoing drought conditions and a hotter, drier climate, Lake Mead is at historic lows, and water levels are expected to decline even further. If Lake Mead falls below 895 feet in elevation, or dead pool, water cannot flow through Hoover Dam to California, Arizona and Mexico.
▶️ Watch to learn more: What happens to Southern Nevada if power pool is reached at Hoover Dam?
Climate change
Drought has become synonymous with the Colorado River over the last 23 years. This term can be misleading, implying a transient condition that will end. Evidence supports the fact that climate change is happening now and that it will have a lasting effect on the availability of Colorado River water supplies.
Today, the best scientific projections available suggest that current Colorado River conditions will not only continue but worsen. Leading climate scientists warn of a permanent shift to a drier future, something known as “aridification.” In simple terms, aridification refers to drying conditions that result from warming, and it represents long-term change rather than seasonal variation or periodic droughts.
While climate change models project that warming trends will continue, the magnitude of change at a given location will depend in part on global mitigation efforts to reduce greenhouse gas emissions. Nevada's Clark County is projected to warm between 5 - 10 degrees by the end of the century. In Southern Nevada, the impacts of climate change are expected to be similar to that of drought. This includes extended durations of low Lake Mead elevations, water quality changes, possible reductions of Colorado River resources, and potential increases in water use to compensate for warmer and drier conditions.
The 2020 State of the Science Report confirms that temperature trends in the Colorado River Basin are increasing and precipitation, snowpack water volume and annual streamflow trends are decreasing.
Adaptive management
The Water Authority is responsible for anticipating future water demands and taking the steps necessary to meet them. Over the years, the agency has taken a number of adaptive management steps to reduce the impacts of drought and climate change on water supplies and facilities.
- Through one of the nation’s most progressive and comprehensive water conservation programs, Southern Nevada has reduced its Colorado River consumption. The community used 27 billion gallons less water in 2021 than in 2002, despite adding more than 745,000 residents during that time.
- The Water Authority has constructed a third drinking water intake and a low lake level pumping station at Lake Mead to ensure continued delivery of Colorado River water to Southern Nevada under low reservoir conditions.
- Through compliance and sustainability efforts, the Water Authority seeks a balance between water resource use and environmental stewardship, including species habitat conservation and protection.
- Through water banking efforts in Nevada, Arizona, California and in Lake Mead, the Authority has accrued more than 2.2 million acre-feet of water. This is more than nine times Nevada’s 2021 consumptive Colorado River water use. Like a savings account, water banking provides the Water Authority with the ability to store water for when it is needed.
Continued water conservation and adaptive management are ongoing priorities as our community responds to drought and climate change.