| | | Mineral deposits on the canyon walls show where Lake Mead water levels used to touch. The reservoir is the lowest it’s been since it was first filled in the 1930s. Photo © J. Carl Ganter / Circle of Blue |
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| Shrinking Reservoirs Trigger Deeper Cuts for Lower Colorado River
The implications of the drying American Southwest and the limits to the region’s water supply are steadily becoming more apparent.
The federal government acknowledged the changing conditions on Monday, declaring a Tier 1 shortage for the lower Colorado River basin. The shortage declaration will force Arizona and Nevada, as well as Mexico to further reduce their withdrawals from the river in 2022.
California, the other lower basin state, is not affected. The declaration also sets the stage for more drastic measures in the near future since Lake Mead is projected to fall another 30 feet over the next two years.
The lower basin was already in a Tier Zero shortage this year, which required modest reductions in water withdrawals from the river by users in Arizona, Nevada, and Mexico. Even so, total water storage in the basin’s reservoirs dropped from 49 percent of capacity at this time last year to 40 percent today. The decline was due to a dry spring and parched soils, which resulted in the second-lowest runoff into Powell on record.
A Tier 1 shortage will demand deeper cuts from the lower basin. Nevada and Mexico will be affected, but the cuts will mostly fall on Arizona, and more specifically, to farmers in Arizona who receive water from the Central Arizona Project canal. |
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| | | Lake Mead sits at a record low. Federal officials are expected to declare a first-ever Tier 1 shortage, which will require water cuts that fall most heavily on Arizona. Photo © J. Carl Ganter / Circle of Blue |
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| The Colorado River Basin’s Daunting New Math
Lakes Mead and Powell, icons of 20th-century water engineering in the American West, are in bad shape.
The story of their decline is written into the edges of the receding siblings — it’s evident in the minerals deposited on the rock walls hundreds of feet above Lake Mead, signs of where water once stood, like a white tea stain on nature’s mug. It’s also evident in the sandbars and sandstone arches of Glen Canyon that are reemerging as Lake Powell ebbs. This story, playing out across decades, is deeply consequential for some of the most rapidly growing and intensely irrigated regions of the country; for stressed ecosystems and endangered species; for Native American tribes; for the more than 40 million people who get a portion of their drinking water from the Colorado River.
Both reservoirs, the largest by capacity in the United States, are puddles of their former selves. Each about one-third full, they sit today at record lows, products of the Colorado River’s unforgiving math, in which demand exceeds supply.
Circumscribed in a body of law and policy known as the Law of the River, the math is complex and arcane, setting water deliveries across seven states and Mexico. New numbers will soon be added, altering the equation. |
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| HotSpots H2O: In Madagascar, Droughts Caused by Climate Change Contribute to Famine
Over the past year, Madagascar's parched landscape has grown even more barren, as the country’s worst drought in over four decades has ravaged food supplies, sweeping hunger throughout the region.
The drought’s human toll is enormous. Over one million people in southern Madagascar need food urgently. Residents have resorted to eating cacti and celebrating the arrivals of usually unwanted, though edible, locust swarms.
As the situation grows increasingly dire, and resources increasingly scarce, the majority of these communities now face outright famine. As famines historically are caused by conflict or political issues, and socioeconomic vulnerabilities, the famine in Madagascar–one of the lowest emitters of carbon and greenhouse gasses in the world–stands out as being heavily influenced by climate change. |
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| What’s Up With Water — August 16, 2021
For the news you need to start the week, tune into “What’s Up With Water” fresh on Monday’s on iTunes, Spotify, iHeart Radio, and SoundCloud. Featured coverage from this week's episode of What's Up With Water looks at: In the United Kingdom, government leaders are hoping to solve two problems with one effort. In the United States, a far-ranging drought is causing wells to dry up across multiple states as groundwater levels decline. In Greenland, warm temperatures are devastating the island’s ice reserves. This week, Circle of Blue looks at a major new climate report, which finds that a warming planet is accelerating the water cycle. |
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| From Circle of Blue's Archives: |
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| | | Lake Mead, the largest reservoir on the Colorado River, is a centerpiece for water supplies in Arizona, California, and Nevada. Mead’s declining water levels, projected to reach record lows in the next two years, will challenge water managers in the basin. Photo © J. Carl Ganter / Circle of Blue |
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| A complex and arcane water banking program in the lower Colorado River basin, adopted in 2007 and later amended, was designed to incentivize water conservation, prevent waste, and boost storage in a waning Lake Mead. The program has already proved its worth, lifting Lake Mead dozens of feet higher than it otherwise would have been and nurturing collaboration among states that will need to work together to surmount daunting challenges of water availability. In the next two years, the program will be tested in another way, becoming a small but important source of water for Arizona and California even as the lake continues to fall to levels that haven’t been witnessed in several generations. Water managers in the basin view the program, called intentionally created surplus or ICS, as a flexible tool for adapting to a drying climate. It is a tool that they will soon call upon. |
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