Aging and undermaintained infrastructure in the United States, combined with changing climate over the coming decades, is setting the stage for more dam disasters like the one that struck Midland, Michigan, last week.

More than 91,000 dams dot the nation—and roughly 15,500 of them could cause fatalities if they failed, according to the National Inventory of Dams. Most of these dams were built many decades ago. By 2025, 70 percent of them will be more than a half century old, according to the American Society of Civil Engineers.

This means many U.S. dams were built with now-outdated standards and methods, as well as for different climate trends. What’s more, dams need continual maintenance to keep operating safely over the decades. Valves