There have only been four times in the history of the drought monitor that we have seen more than 40% U.S. drought coverage as we come into early May, The current U.S. drought coverage is 46.6% of the lower 48 states in drought!
The Southwest seems to be the worst affected and water shortages are brewing… in fact, the region may be headed into a period more severe than any on memory as the so-called “megadrought” deepens. Projections released by the U.S. Bureau of Reclamation indicate that water levels in Lake Mead, America’s largest reservoir, could plummet low enough to trigger a water emergency declaration for the first time ever in the United States and result in the largest mandatory Colorado River reduction in history.
The agency’s models project Lake Mead will fall below 1,075 feet (328 meters) for the first time in June 2021. That’s the level that triggers what’s called a Tier One shortage under agreements negotiated by seven states that rely on Colorado River water: Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming. The agency will release its next major update in August. An initial round of cuts was triggered in the summer of 2019 after Lake Mead reached 1,090 feet (332 meters), with Arizona and Nevada voluntarily implementing minor cutbacks under a drought contingency plan for the river. If projections have not improved with the August update, the next tier of cuts would be implemented starting in January 2022.
An emergency declaration would automatically subject Arizona and Nevada to further water cuts. California would participate in cuts at lower shortage levels if the reservoir continues to fall. According to Capital Press, of the first 7.5 million acre-feet of mainstem water in the Lower Basin, California is entitled to 4.4 million acre-feet, Arizona to 2.8 million acre-feet and Nevada to 300,000 acre-feet. Each state’s water resources department is responsible for allocating water and making cuts as needed if a shortage is declared.
Nevada says mitigation efforts should insulate it from any impacts. That’s not the case for central Arizona farmers though, which are first in line to cut their water share under the 2019 drought plan and could see as much as one-third of their water supply cut. Officials from Central Arizona’s water management agency, known as CAP, anticipate the first-tier shortage will likely continue into 2023.
CAP’s water allocations won’t dole out cuts evenly across the board with some counties seeing less than others. Pinal County farmers who now receive water from the CAP Canal expect to see their deliveries reduced by more than half next year, and then slashed to zero in 2023 under the current plan. Some of that will be offset by enabling irrigation districts to pump more groundwater. However, infrastructure projects to support more groundwater extraction are running behind and unlikely to be finished by 2023 as planned.
The Colorado River is the West’s most important water source, running down from the Rocky Mountains through the manmade reservoirs of Lake Powell and Lake Mead, the deserts of the U.S. Southwest, and eventually across the border into Mexico. The river, its tributaries, and land make up the Colorado River Basin which is divided into two distinct regions known as the Upper Basin and Lower Basin. The Upper Colorado Region alone irrigates about 3.5 million acres of farmland. Lake Powell represents the majority of the Upper Colorado River Basin’s water supply, while Lake Mead supplies the Lower Basin.
The entire Colorado River Basin has been mired in a drought that began in 2000 and has seen the river slipping closer to a shortage for years now. Unfortunately, the drought has worsened this year, with a disappointing monsoon season followed by an equally disappointing snowpack season. Lake Mead, the biggest reservoir on the river, has declined dramatically over the past two decades and now stands at just 39% of its full capacity while Lake Powell is at 36%.
The Bureau of Reclamation also predicts Lake Mead may drop to the point that it threatens electricity generation at Hoover Dam. The dam’s hydropower serves millions of customers. To prepare for a future with less water, the bureau has spent 10 years replacing parts of the dam’s turbines to operate more efficiently at lower water levels. But Len Schilling, a dam manager with the bureau, noted that less water moving through the Hover Dam will mean less hydropower to go around.
The seven states in the Colorado River Basin are currently preparing for negotiations over the next set of rules when the current contingency plan expires in 2026. Ahead of that, disagreements are heating up over plans in the Upper Basin to take more water from the river. One of the most controversial is Utah’s proposal to build a 140-mile pipeline that would transport 86,000 acre-feet of water per year from Lake Mead to support St. George, one of the nation’s fastest-growing cities. In September, representatives of the six other states pushed back against Utah’s pipeline proposal, voicing concerns in a letter to the federal government and warning of a potential court battle. Wyoming has several new dams on the drawing board, as does Colorado, which is also planning a new diversion from the headwaters of the Colorado River to Denver and other cities on the Rocky Mountains’ east slope.
Meanwhile, the Klamath River Basin along the Oregon-California border is at a historic low. Farmers and ranchers that are part of the Klamath Project were notified earlier this month that they will receive just 33,000 acre-feet, dramatically lower than the bureau’s original estimate in March of 130,000 acre-feet and barely 8% of historical demand. The Klamath Project provides irrigation for 230,000 acres of farmland in Southern Oregon and Northern California. The Bureau of Reclamation’s current plans are designed to prevent the lake from dipping under 4,138.3 feet, which is expected to protect a fish species important to the region’s indigenous Klamath Tribe. The Tribe says the level is insufficient and is now suing the Bureau. (Sources: Capital Press, Associated Press, Gizmodo, LA Times)
