A critical Colorado River reservoir relied on by California and millions of people across the West has sunk to its lowest level on record — putting both water supplies and hydroelectric power generation under growing pressure.

Lake Powell fell to an elevation of 3,519.91 feet above sea level Saturday — edging below the previous record set in April 2023, according to federal data cited by ABC30.

The reservoir has dropped more than 20 feet since the start of the year and is about 30 feet above the level where its turbines can no longer generate hydroelectric power, the outlet reported.

Federal officials warned in April that a “major intervention” could be needed to keep Lake Powell from reaching that threshold before the end of the year.

The record comes roughly a week after Lake Mead, the Colorado River’s other major reservoir, also fell to a historic low.

Together, the reservoirs form a crucial part of a river system that provides water and power across the Southwest and supports more than 40 million people in California, Arizona, Nevada, New Mexico, Utah, Wyoming and Colorado.

Years of heavy water use, rising temperatures, and an exceptionally dry winter have accelerated losses across the river system, according to ABC30.

The latest decline comes as California and the six other Colorado River Basin states remain at odds over how to manage the shrinking supply over the long term.

The U.S. Bureau of Reclamation proposed a 10-year plan in July that could result in major water cuts for California, Arizona and Nevada.

Lake Powell and Lake Mead are now both at their lowest levels in nearly seven decades, with federal data indicating they could fall even further, per the outlet.

The falling water has also disrupted the recreation and tourism industry surrounding Lake Powell.

Marinas have adjusted to the retreating shoreline, with boat ramps closing or relocating, new ramps being built, and some marinas temporarily moved into deeper water.