Gov. Tim Walz is asking the legislature to approve a $293 million bond program to retrofit the state’s water infrastructure to keep up with climate change.

Last year, more than 20 places in Minnesota set annual precipitation records. That includes the Twin Cities and Rochester, where more than 55 inches fell. Minnesota is now about five inches wetter on average than in 1980.

These heavier 21st century rains are overwhelming our 20th century stormwater infrastructure.

“Not only are we getting wetter in general, but more of our rainfall is coming in more intense storms,” said Randy Neprash, a stormwater regulatory specialist with Stantec Consulting and the Minnesota Cities Stormwater Coalition. “Everybody has seen what a really intense storm does to an urban stormwater system, but you can get those sort of impacts at scales where you have real problems, where you can jeopardize property, where people can get injured or even killed.”

Neprash said most cities are using computer modeling to assess whether their stormwater systems are up to the task of these rain bursts. The systems can apply predicted rainfall levels to existing systems to see how they would respond in real life, then engineers can prioritize upgrades.