In September 2023, more than 11,000 people died after torrential rainfall triggered the collapse of two dams in Libya (1). In May 2024, a flash flood in Mashhad, Iran, led to loss of lives because of poorly designed and malfunctioning stormwater drainage systems (2). Developing nations will increasingly confront similar hazards as their aging water infrastructure encounters more frequent and intense storms, population growth, and urbanization. Financial shortfalls, mismanagement, and corruption complicate efforts to upgrade infrastructure, exacerbating the dangers. In September 2023, more than 11,000 people died after torrential rainfall triggered the collapse of two dams in Libya (1). In May 2024, a flash flood in Mashhad, Iran, led to loss of lives because of poorly designed and malfunctioning stormwater drainage systems (2). Developing nations will increasingly confront similar hazards as their aging water infrastructure encounters more frequent and intense storms, population growth, and urbanization. Financial shortfalls, mismanagement, and corruption complicate efforts to upgrade infrastructure, exacerbating the dangers. Science