How cities are preparing their water infrastructure for bigger storms

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, Minn., where more than 55 inches fell. Minnesota is now about 5 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 and apply the same scenarios to simulated upgrades so cities can plan for the future.

Neprash spoke with Climate Cast host and MPR chief meteorologist Paul Huttner. Hear the conversation using the audio player above.