Lake Mead – The Largest Reservoir in the US – Drops to a Report Low
The reservoir stands at its lowest stage for the reason that Thirties.
Lake Mead is the most important reservoir in the US and a part of a system that provides water to at the very least 40 million folks throughout seven states and northern Mexico. It stands in the present day at its lowest stage since Franklin Delano Roosevelt was president. This implies much less water will likely be portioned out to some states within the 2022 water 12 months.
As of August 22, 2021, Lake Mead was filled to only 35 % of its capability. The low water stage comes at a time when 95 % of the land in 9 Western states is affected by some level of drought (64 % is excessive or worse). It continues a 22-year megadrought which may be the area’s worst dry spell in twelve centuries.
These natural-color photos have been acquired in August 2000 and August 2021 by Landsat 7 and Landsat 8. The tan fringes alongside the shoreline in 2021 are areas of the lakebed that may be underwater when the reservoir is crammed nearer to capability. The phenomenon is sometimes called a “bathtub ring.”
The lake elevation knowledge under come from the U.S. Bureau of Reclamation, which manages Lake Mead, Lake Powell, and different parts of the Colorado River watershed. On the finish of July 2021, the water elevation on the Hoover Dam was 1067.65 ft (325 meters) above sea stage, the lowest since April 1937, when the lake was nonetheless being crammed. The elevation on the finish of July 2000—across the time of the Landsat 7 photos above and under—was 1199.97 ft (341 meters).
At most capability, Lake Mead reaches an elevation 1,220 ft (372 meters) close to the dam and would maintain 9.3 trillion gallons (36 trillion liters) of water. The lake last approached full capacity within the summers of 1983 and 1999. It has been dropping ever since.
In most years, about 10 % of the water within the lake comes from native precipitation and groundwater, with the remainder coming from snowmelt within the Rocky Mountains that melts and flows right down to rivers, touring via Lake Powell, Glen Canyon, and the Grand Canyon on the way in which. The Colorado River basin is managed to supply water to thousands and thousands of individuals—most notably the cities of San Diego, Las Vegas, Phoenix, and Los Angeles—and 4-5 million acres of farmland within the Southwest. The river is allotted to states and to Mexico via legal guidelines just like the 1922 Colorado River Compact and by a current drought contingency plan announced in 2019.
With the Lake Mead reservoir at 35 % of capability, Lake Powell at 31 %, and the complete Decrease Colorado system at 40 %, the Bureau of Reclamation announced on August 16 that water allocations can be reduce over the subsequent 12 months. “The Higher [Colorado] Basin skilled an exceptionally dry spring in 2021, with April to July runoff into Lake Powell totaling simply 26 % of common regardless of near-average snowfall final winter,” the USBR assertion mentioned. ”Given ongoing historic drought and low runoff situations within the Colorado River Basin, downstream releases from Glen Canyon Dam and Hoover Dam will likely be diminished in 2022 because of declining reservoir ranges. Within the Decrease Basin the reductions characterize the primary “scarcity” declaration—demonstrating the severity of the drought and low reservoir situations.”
For the 2022 water 12 months, which begins October 1, Mexico will obtain 80,000 fewer acre-feet, roughly 5 % of the nation’s annual allotment and Nevada’s take will likely be reduce by: 21,000 acre-feet (about 7 % of the state’s annual apportionment). The most important cuts will come to Arizona, which can obtain 512,000 fewer acre-feet, roughly 18 % of the state’s annual apportionment and eight % of the state’s complete water use (for agriculture and human consumption). An acre-foot is sufficient water to provide one to 2 households a 12 months.
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