More than 200 Minnesota cities, from tiny Lauderdale to wealthy Rochester, will have to devise ways to keep the rain where it falls as part of a controversial new mandate designed to protect urban streams and lakes from the dirt and pollutants that wash off streets and yards along with the stormwater.
The cities, for the first time, will be required to maintain or reduce the volume of runoff leaving their systems, under a stormwater management plan approved Tuesday by the Minnesota Pollution Control Agency governing board. The plan also requires the cities to account for their share of pollutants such as phosphorus and sediment that foul many urban lakes and streams.
Although it's been in the works for years, the proposal triggered fierce objections Tuesday from local officials, who say they are doing all they can to to improve water quality and that the new rules will add unknown millions of dollars in costs and responsibilities to cities that are already financially strapped and unable to ask residents for more fees.
"This is a huge undertaking," said Nancy Burke, an attorney for the Minnesota League of Cities. Asking cities to control stormwater volume not just pollutants is "stepping way out into new territory for the state," she said.
But after listening to hours of testimony, the board approved the plan unanimously, along with a promise by Commissioner John Link Stine to provide the cities with all the assistance and support possible.
"This is one of the questions of our time," said board member Kathryn Draeger, a farmer and agronomist at the University of Minnesota. "How to balance declining resources with increasing pressure on our water resources."
The new stormwater permitting process essentially requires each city to adopt the best way to hold water on the land techniques that could range from rain gardens to holding ponds to pervious pavements to new sediment-collecting baffles in storm sewers. The idea is to mimic the natural hydrology of each place in the most effective way to control pollution, the agency said. It can reduce phosphorus, a nutrient that causes explosions of green algae in lakes, by 90 percent, compared with the 50 percent that is typical of current water treatment systems, according to PCA officials.
That's a sharp contrast to the way that most urban areas are designed today. Pavement, lawns, concrete driveways and rooftops are, for the most part, all designed to rush water off the surface and into sewers as fast as possible carrying dirt, chemicals, oils toxins, yard chemicals and nutrients that end up in lakes and streams, along with too much water that erodes banks.