Floods bring rare relief to US Southwest reservoirs as Lake Powell rises 20 feet

Recent flooding in the U.S. Southwest has brought much-needed relief to parched reservoirs that had hit record lows due to a prolonged megadrought. The storms, which occurred in late October and early November, sent torrents of water through creeks and flooded communities, forcing hundreds of evacuations. While most of the water will replenish depleted lakes and underground aquifers, Martin Hoerling, a climate scientist at the University of Colorado, Boulder, noted that it's an unexpected boost from Mother Nature.

Lake Powell, the second-largest reservoir in the U.S., rose more than 20 feet from its mid-September low, outpacing its gains from this year's snowmelt. However, the reservoir still only stands at over a quarter full, with 15 of its 17 boat launches still unusable. Despite the floods, water supply concerns remain high. In the region, cities reported some of their wettest weather in decades, with Pagosa Springs, Colorado, under water restrictions for over 10,000 residents. Those restrictions have now been lifted, with restaurants only serving water upon request.

The storms have also replenished Upper Lake Mary, which supplies Flagstaff, Arizona, with up to 40% of its water. Flagstaff water production manager Brian Huntzinger said that storms dumped more than 3 billion gallons of water into the town's surface water supply since early October, providing a crucial buffer for the region's water-dependent operations.

In central Arizona, heavy floodwaters trapped people in their homes and gushed into streams feeding the Verde River. Water officials released water from two nearly full dams into the Verde's normally dry stretch in metro Phoenix. Wet weather is unlikely to alter decisions on the Colorado River's water releases for now. The U.S. Bureau of Reclamation, which manages the reservoirs, is waiting to see when the snowpack peaks, typically in April, before making any changes.

While some Arizona cities have agreed to fund preliminary work to reduce reliance on the Colorado River, others are challenging the water-use reduction plan in court.