Can the Southwest Survive With Less Water?Sometime next month, for the first time, the federal government is likely to declare a water shortage ...

Can the Southwest Survive With Less Water?Sometime next month, for the first time, the federal government is likely to declare a water shortage ...Can the Southwest Survive With Less Water?

Sometime next month, for the first time, the federal government is likely to declare a water shortage at Lake Mead.

This vast turquoise reservoir, formed in 1935 when the Hoover Dam corked the Colorado River in Arizona and Nevada, is part of a broader network of natural and artificial aqueducts and dams that supplies water to 40 million people and homes, farms, manufacturers and businesses across several states, tribal lands and parts of Mexico. Lights stay on in Phoenix, Tucson, Las Vegas, San Diego, Los Angeles and other Southwestern cities because Hoover Dam hydropower helps generate the region’s electricity.

But the lake is shrinking, faster and sooner than hydrologists and other experts predicted. A stark white band of dry rock, 120 feet wide, circles its craggy perimeter, marking how far the water line has fallen in the ongoing drought. Locals call it the “bathtub ring.”

Walking Lake Mead’s shoreline in the blistering July sunshine offers other reminders of the receding water. Swimmers gather in an area that they call a beach but is really an exposed portion of the reservoir’s rocky floor — some distance from the place further inland where people used to sunbathe. Marina ramps are closed because the water isn’t high enough to properly launch a boat. Formerly submerged infrastructure supporting enormous “straws” that suck water from the reservoir to be delivered to Las Vegas now tower above the lake. Saddle Island, home to a major water treatment plant, is so parched, it’s no longer an island — it’s a peninsula.

Lake Mead and its troubled fellow reservoir upriver, Lake Powell, symbolize a broader threat. The entire Southwest has been baking in a 21-year drought and in this summer’s successive heat waves, which have also roasted Northwestern states. How communities and businesses everywhere live with this change — how they adjust to the idea that water is a precious, waning resource rather than an abundant, inexpensive commodity — is being tested in the Southwest. Dry, sizzling summers and warmer winters that restrict water supplies may now be the norm, courtesy of a permanently altered climate.

“A lot of our problems are creeping. They aren’t acute. Drought isn’t something that just happened here — it’s been going on for two decades,” says Kristen Averyt, Nevada’s climate policy coordinator and a research professor at the University of Nevada at Las Vegas. “But this recent heat wave should be sobering because this is arguably the most significant heat wave North America has experienced. And it’s here to stay.”

Interlocking legal agreements, built on earlier pacts dating back at least a century and layered atop a hodgepodge of local rules, govern how Colorado River water is shared among seven states, Native American nations and Mexican territories. In 2019, after years of thorny negotiations over a diminishing water supply, states and the federal government signed the Drought Contingency Plan, which lays out how water will be doled out if a shortage occurs.

When the plan was signed, Arizona and Nevada accepted reduced water allocations from Lake Mead — a feature of the DCP known as Tier Zero. California was initially spared from cutbacks. Colorado, New Mexico, Utah and Wyoming are served water from Lake Powell, where water levels have plunged; a shortage may be declared next year.

The hope was that these first, incremental steps might slow Lake Mead’s depletion and delay more severe restrictions. The reservoir’s surface elevation at Tier Zero was 1,090 feet, well below its peak of 1,226 feet in 1983. When the reservoir drops to 1,075 feet, it will become Tier 1 — which represents just 40% of total capacity. (Other, more wrenching shortfalls accompany plunges to Tiers 2, 2a, 2b and 3.)
SOURCE:https://www.bloomberg.com/graphics/2021-opinion-us-drought-southwest-arizona-water-crisis/