Service Saturdays Put Lowry Hill Neighbors to Work

Beachgoers who feel closure signs have grown more common are not imagining it. Heavier, more frequent rainstorms are washing more bacteria into the lakes, and the Minneapolis Park and Recreation Board recorded 15 beach closures in 2024, the most in 11 years and matching the wettest summer in that span.

The mechanism is direct. When heavy rain falls on a city full of hard surfaces, it sweeps contaminants off streets, lawns and rooftops into the lakes; the most common sources of the bacteria are people, pets and wildlife. "Certainly this year is a good example of that," John Bilotta, senior research and extension coordinator with the Minnesota Stormwater Research Program at the University's Water Resources Center, said of how a rainy season drives pollutants to the beaches. Minnesota's summers have grown wetter, with more rain arriving in intense bursts that overwhelm the ground's ability to absorb water and deliver a concentrated slug of bacteria at once.

The Park Board tests each beach weekly between Memorial Day and Labor Day, averaging E. coli readings as a proxy for fecal contamination. "If we're closing a beach, we are doing that because we believe that there is a higher chance that people could get sick," said Rachael Crabb, the agency's water resources supervisor. Some lakes fare far worse than others: Lake Hiawatha, the only one directly connected to Minnehaha Creek, a stormwater outlet for a dozen cities, has been closed 388 days over the past 11 years.

For the Park Board, a wetter climate turns water-quality management into a moving target. Structural defenses such as constructed wetlands and restored shorelines intercept runoff, but they were sized for the storms of the past, not the heavier bursts the region now sees. The agency, whose environmental management is directed by Deb Pilger, has also expanded testing to include cyanobacteria, the blue-green algae that thrives in warm, nutrient-rich water and can sicken people and pets.

None of this makes the lakes unusable, only less predictable. Holding the beaches open in a wetter future will take more than the structures already in the ground; it will take the whole watershed, public agencies and private property owners alike, slowing runoff harder than before.