KVIG Informative

Heavy rain across the Four Corners region sent a burst of water into Lake Powell this month, pulling the reservoir back from its lowest point on record. Lake Mead, downstream and Nevada’s actual water source, barely noticed.

Lake Powell’s water level rose to roughly 3,529 feet above sea level by Oct. 25, climbing about 10 feet above the record low of 3,519 feet the reservoir touched in September, according to National Weather Service data and the Bureau of Reclamation’s own Lake Powell measurements.

The rise traces to heavy rainfall across the Four Corners region of Utah, Colorado, New Mexico and Arizona, compounded by remnants of two tropical storms that moved through the Southwest in October. The San Juan River alone contributed roughly 251% of its average October flow into Lake Powell this month, well above the roughly 13% share it typically provides.

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Lake Mead, situated downstream of Lake Powell behind Hoover Dam, has not seen a comparable rise, since most of the recent rainfall fell upstream of Glen Canyon Dam. Lake Mead set record low water levels on Oct. 9 and again on Oct. 15, and its level has risen just a fraction of a foot over the same two-week stretch that lifted Lake Powell by roughly 10 feet.

The Bureau of Reclamation’s October 24-Month Study, released Oct. 14, was the first projection in months to come in better than the prior month’s forecast. The study still shows both reservoirs ending the year lower than their current levels, and projects Lake Powell could fall below 3,510 feet during the coming water year — a threshold that puts the reservoir in the new federal operating guidelines’ infrastructure protection range.

The added water gives Glen Canyon Dam additional cushion to continue generating hydropower, which becomes difficult to sustain once Lake Powell’s level falls too close to the dam’s intake structures.

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The rise comes as Nevada, the Colorado River Commission of Nevada and the Southern Nevada Water Authority pursue a federal lawsuit challenging the Department of the Interior’s new 10-year operating plan for both reservoirs, arguing the plan could eventually cut Nevada’s Colorado River allocation by up to 71% while imposing no mandatory cuts on Upper Basin states.

A few feet of rain-driven relief at Lake Powell doesn’t change the math Nevada’s lawsuit is built on. Lake Mead, the reservoir Southern Nevada actually draws its water from, is still sitting at a record low — and the storm that briefly rescued its sister reservoir upstream never made it that far south.