Stormwater runoff has the potential to choke the life out of suburban lakes and streams.
Rainwater laced with lawn chemicals, moldy leaves, grass clippings and trash flows from driveways to storm drains to lakes, fueling algae growth that hurts other plants and wildlife.
A new Roseville city project soon will divert millions of gallons of that mucky water from flowing into Lake McCarrons each year. It will be captured, filtered and used to sprinkle the softball field at Upper Villa Park.
It's part of a new generation of projects across the Twin Cities designed to reuse or filter stormwater before it flows back into lakes and rivers.
• In St. Paul, rainwater from a Metro Transit Green Line station is stored and used to water the baseball diamond at CHS Field and to flush toilets at St. Paul Saints games.
• In Minneapolis, stormwater from the roof and parking lot of Edison High School will be used to water the football field.
• St. Anthony built an underground tank next to City Hall to collect runoff for irrigation use. Three fountains sit atop the tank, and the site is popular for wedding portraits.
• St. Anthony, the Mississippi Water Management Organization, Minneapolis, St. Anthony and Hennepin County are collaborating to construct a $1.6 million underground stormwater treatment and research facility. It will treat 169 million gallons of runoff annually, removing 39 tons of sediment.
• The Roseville system at Villa Park is expected to capture 10 million gallons of runoff a year and reduce potable water use by 1.3 million gallons annually.
Roseville's project is really a pre-emptive strike, said Forrest Kelley, regulator and construction project manager for the Capitol Region Watershed District, which is working with the city on the project.
"Lake McCarrons has good water quality, but in recent years we've seen a decrease," he said.
Construction on the $1 million water storage and infiltration system started this month. The tank will be buried beneath the playing field and parking lot.
"It will also help to reduce erosion in the area," said Lonnie Brokke, Roseville's director of parks and recreation. In previous years, runoff caused mudslides that closed trails and damaged parkland.
The project is being paid for in part with Minnesota Clean Water, Land and Legacy funds from the Minnesota Pollution Control Agency and Board of Water and Soil Resources. Roseville and the watershed district are also contributing.
Years of damage
Managing runoff is a critical issue for the urban watershed district, which includes St. Paul, Roseville, Maplewood, Falcon Heights and Lauderdale. When the suburbs were built in the 1950s and '60s, stormwater was directed to wetlands and lakes. In the 1980s, scientists and city planners started to realize some of the damage it was causing.
Polluted runoff is a leading cause of impairment to the nearly 40 percent of surveyed U.S. water bodies that do not meet water quality standards, according to the U.S. Environmental Protection Agency.
About 42 percent of the land in the Capitol Region watershed is now paved surfaces or rooftops that don't absorb water.
"The large amount of runoff coming through the Villa Park wetland system acts like one big funnel. It shoots out into Lake McCarrons," Kelley said.
The area provides drainage for 250 acres of the city.
He said stormwater reuse projects are the wave of the future, but "one of the biggest challenges in all of our capital improvement projects is finding the land for construction."
Drains lead to the river
Scientists say such efforts protect the lakes as well as the 2,300 miles of the Mississippi River and beyond.
"It's important to realize when it goes down the stormwater drain, it's a direct pipe to the river. In most cases, there is no treatment. It carries a lot of pollution that can impact the river locally and downstream," said Stephanie Johnson, a manager and scientist with the Mississippi Water Management Organization.
"We have the benefit of being at the headwaters — this is a really clean river right here," she said. "Downstream there are a lot of problems. There is a huge dead zone in the Gulf of Mexico which the Mississippi River contributes to."