Local Cities take a Cost-Effective Approach to Reducing Water Pollution

St. Paul Park street raingarden

Summer in Minnesota is the season for backyard barbeques, 4th of July fireworks, of course, road construction. It’s always a mixed blessing when your neighborhood is slated for street repairs. On the one hand, you have to deal with the inconvenience and noise, on the other, you can say goodbye to the potholes that swallowed two poodles and a Prius during the spring. Along with the typical notices and schedules, some cities are starting to send their residents an unusual request when road maintenance projects begin. “We would like to build a free garden for you along the edge of the road,” they say. Those who receive the notices are often suspicious. After all, we’re taught that nothing in life is free. “What’s the catch?” they ask. “Will this increase my taxes?” These gardens, however, really do come free of charge. All that the cities ask in return is for homeowners to care for them like any other planting in their yards, water the plants a few times until they get established, and pull some weeds occasionally to keep them looking good. Of course, the cities do have an ulterior motive.

Yes, it turns out that these free gardens are part of a secret plot to reduce stormwater pollution so that we have clean water for fishing, swimming and boating. Called raingardens, the plantings capture rain and melting snow that runs off of rooftops and driveways and into the street before the runoff goes into storm sewers that connect to local lakes and streams. Raingardens soak the water into the ground within one to two days, and the plant roots and soil filter out nutrients and pollutants so that only clean water percolates down into the groundwater.  Because they are wet for such a short period of time, they do not allow mosquitoes to breed, and on most days they look like any other garden.   

By building raingardens in right-of-way areas during road repair projects, cities are able to take a big bite out of stormwater pollution at a minimal cost. During a typical road project there’s a crew of contractors and public works staff on site with machinery to grade, pave and replace curb and gutter. With all of the proper equipment on hand, it takes little extra effort to dig small depressions for raingardens and include openings in the new curb line that allow stormwater flowing down the street to detour into the gardens. Incorporating raingardens into regularly scheduled road maintenance projects helps to reduce some of the planning that would normally be needed to install raingardens throughout an entire neighborhood and because they are all being installed at the same time, the cities save money on plants and landscaping services as well.

Maplewood was the first East Metro city to start building raingardens during road projects nearly ten years ago. In recent years, several cities in Washington County have begun to follow suit, with ample assistance from the Washington Conservation District and local Watershed Districts as well. St. Paul Park built several raingardens during road repairs three years ago, all of which are reducing runoff pollution to the Mississippi River. After a few growing seasons, the plants have filled in quite well and are attracting birds and butterflies as well. Lake Elmo is planning to install around a dozen raingardens this summer in a neighborhood near Tartan Park. It will be the second year the city has included raingardens in their road projects, and the plan is to make this practice the new normal. Stillwater has been building road right-of-way raingardens for three to four years now. Raingardens along Eagle Ridge Road reduce runoff pollution to Lake McKusick, while raingardens in other parts of the city protect Lily Lake and the St. Croix River. Up at the top end of the county, Forest Lake has built raingardens in several dead-end cul-de-sacs around Forest Lake, which reduce runoff pollution and improve shoreline wildlife habitat. Meanwhile, North St. Paul has a long term plan to work with the Ramsey-Washington Metro Watershed District to transform their city streets with raingardens and pedestrian-biker friendly features over the next decade or so.

These local cities deserve credit for applying creativity to a complicated problem and finding a cost-effective way to reduce water pollution even during difficult economic times. They’re planning ahead, recognizing that it’s cheaper and easier to install raingardens now than to clean up polluted waterways later. For local residents, it’s a winning solution as well. Some are lucky enough to get free gardens for their yards, but even those who don’t enjoy the clean water and the garden lined boulevards around town.