| U.S. declares first-ever Colorado River water shortage
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U.S. declares first-ever Colorado River water shortage

Glen Canyon Dam, Lake Powell, ArizonaExtreme and accelerating drought conditions are drastically depleting water levels in the Colorado River Basin, which supplies water from Rocky Mountains snowfall runoff to 40 million people from Wyoming to Mexico. The record lows prompted historic action last week when federal officials declared the river’s first-ever water shortage and mandatory cuts in accordance with the 2007 Colorado River Operating Guidelines. (Photo credit: Glen Canyon Dam, Lake Powell, Arizona/U.S. Bureau of Reclamation)

An Aug. 16 press release from the U.S. Bureau of Reclamation (USBR) stated, “Given ongoing historic drought and low runoff conditions in the Colorado River Basin, downstream releases from Glen Canyon Dam and Hoover Dam will be reduced in 2022 due to declining reservoir levels. In the Lower Basin the reductions represent the first ‘shortage’ declaration—demonstrating the severity of the drought and low reservoir conditions.”

Seven impacted Western U.S. states -- Colorado, Utah, New Mexico, Wyoming, California, Nevada and Arizona – took additional action to help mitigate years of declining water levels by participating in many water conservation efforts (such as the Pilot System Conservation Agreement) and implementing measures specified in a 2019 Drought Contingency Plan in coordination with the USBR, which operates the Colorado River system. The measures helped reduce demands on Lake Mead and included a variety of conservation efforts, water source diversification, underground water storage and reductions in agriculture irrigation.

However, the ongoing drought, reduced snowpack and hotter and drier weather have decreased the flows of the Colorado River and resulted in Lake Mead and Lake Powell reservoirs falling to record low levels. The unprecedented low level at the Lake Mead reservoir triggered mandatory cuts to Colorado River water deliveries in Arizona (18% of annual apportionment), Nevada (7%) and parts of Mexico (5%) beginning in 2022.

Jim Lockhead, Denver Water“One clear lesson is that we can’t look to the past as a reliable indicator of the future,” said Jim Lochhead (pictured right), Denver Water’s CEO/Manager. “We are charting new territory and must take actions that reflect a new reality, without banking on the idea that things will return to ‘normal’. There is a tremendous need for a united approach across the Basin to find a way forward, along with investment at all levels of government in climate resiliency on a major scale.”

The USBR press release stated, “Today’s announcement of a Level 1 Shortage Condition at Lake Mead underscores the value of the collaborative agreements we have in place with the seven basin states, Tribes, water users and Mexico in the management of water in the Colorado River Basin. While these agreements and actions have reduced the risk, we have not eliminated the potential for continuing decline of these critically important reservoirs.”

Colorado River Basin geography

Several man-made reservoirs store water from the 1,450-mile Colorado River, which is a source for drinking water, irrigation and hydropower. These include the river’s two largest reservoirs, Lake Powell and Lake Mead. Both massive reservoirs are key to the reliability of the region’s water supply. Their alarmingly low levels impact the environment and wildlife as well as farming, hydropower and recreation. (Click here for a Denver Water video series about the Colorado River)

In the Upper Basin, Lake Powell, located on the Utah-Arizona Border, serves as a savings account for the Upper Basin states of Colorado, Utah, New Mexico and Wyoming, to meet delivery obligations to the Lower Basin. 

“Denver Water has a scenario planning approach that addresses a variety of situations out to 50 years,” Lochhead said. “Our planning is reflected in our investments, and our investments are focused on resilience, sustainability, conservation and response. Examples include our partnerships in forest management to reduce the risk of catastrophic wildfire to our watersheds, a new water treatment plant that will generate its own electricity, a conservation and efficiency program that has kept customer water use essentially flat for decades and ongoing work to diversify our supplies in a way that gives us greater options in difficult times.”

Lake Powell releases water to the Lower Basin states of California, Nevada and Arizona, where Colorado River water is captured and stored in the Lake Mead reservoir, the country’s largest reservoir located on the Arizona-Nevada border near Las Vegas. The Lower Basin continues south into Mexico, and the Republic of Mexico also participates in shared shortages and contributions under a Binational Water Scarcity Plan.

John Entsminger SNWA“Every Colorado River water user must adapt to the new reality of a warmer and drier climate where today’s Colorado River hydrology is not what it was a century ago,” said John Entsminger, general manager of the Southern Nevada Water Authority. “Managing the Colorado River into the future will require all of us that share this critical river to continue to collaborate and use less.”

Extreme measures

The 2019 drought contingency plan helped ensure enough water remained in Colorado River Basin reservoirs to manage water supplies. In the Upper Basin, reservoirs upstream of Lake Powell made emergency releases of water. In the Lower Basin, states curtailed water usage.

USBR reported that Lake Mead’s projected elevation on Jan. 1, 2022, is about 9 feet below the Lower Basin shortage determination trigger and about 24 feet below the drought contingency plan, triggering the first-ever Level 1 Shortage Condition. Lake Powell’s projected elevation on Jan. 1, 2022, is about 45 feet above the minimum power pool and it will operate in a Mid-Elevation Release Tier.

Under the Colorado River’s 2007 Operating Guidelines, deeper Tier 2 and Tier 3 cuts are on the table for as soon as 2023 should extreme conditions persist. 

“Relying on the best available scientific information to guide operations, investing in water conservation actions, maximizing the efficient use of Colorado River water and being prepared to adopt further actions to protect the elevations of Lake Powell and Lake Mead remains reclamation’s priority and focus,” stated the press release.

More information about water resource planning and sustainability is available on AWWA’s online resource page and at drought.gov. Register here for AWWA’s Aug. 31 webinar, "An Eye to the Future: Examining Long-term Drought and Climate Change Trends." 
 

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