Above and beyond. MPCA recognizes Ramsey County for responsible stormwater runoff management.
As Minnesotans, we love to have beautiful parks and recreation areas in our communities for all to enjoy. We also want those parks to have amenities that provide accessibility while maintaining the integrity of precious natural resources. Ramsey County Parks and Recreation Department provided that balance by installing a permeable asphalt trail in Vadnais-Snail Lakes Regional Park earlier this year.
According to state stormwater regulations, construction projects that add an acre or more of new impervious surface (i.e., asphalt, concrete, roofing) are required to build permanent stormwater management systems that collect and treat runoff that would be generated by the increase in impervious surface. The size of the Vadnais-Snail Lakes project was 5.5 acres, including the one-mile trail, but by using the permeable asphalt, the net increase in impervious surface was zero.
This is the third such project in Ramsey County since 2013. According to Ramsey County Landscape Architect Gus Blumer, permeable asphalt is preferred because, “it eliminates sheet flows of stormwater that could potentially run into area lakes. Stormwater infiltrates into the asphalt and more slowly seeps through gravel underneath, and adjacent turf areas, helping slow volume rates.” Blumer also says the 20-25% of void space in permeable asphalt is more than enough space for water/ice to expand, and has eliminated concerns about cracking or trail heaving with changing seasons.
Permeable asphalt requires little to no de-icer in the winter, as the asphalt warms up in the sun and ice melts into the openings of the surface. This is especially beneficial for this project since the trail runs next to Vadnais Lake, which is a highly sensitive lake and is a drinking water source for St. Paul.
The Vadnais-Snail Lakes trail was installed by T. A. Shifsky & Sons contractors, and they have detailed information on the uses and benefits of permeable asphalt on the company’s Eco Paving web page. Learn more about the many parks, trails, and recreation opportunities in Ramsey County on its Parks & Trails web page.
For providing residents with parks and trails that minimize environmental impacts to natural resources, the MPCA thanks Ramsey County Parks and Recreation Department for responsible stormwater runoff management.