Protecting Water Quality in Urban Areas: Local Planning Approaches for Implementing Stormwater Best Management Practices at the Site Level

Abstract

With constant increases in development and the conversion of natural land cover to urban surfaces, comes increased stormwater runoff. Research has indicated that stormwater runoff is the primary source of pollutants found in surface waters and contains a toxic combination of oils, pesticides, metals, nutrients, and sediments (MPCA 2008). Moreover, studies have shown that once a watershed reaches just 10% impervious surface cover, water resources are negatively impacted (Schueler, 1994). Past efforts to control stormwater at the local level have focused on detaining peak flows and have paid little attention to pollutant reduction or restoring natural hydrologic flow regimes. However, with the growing popularity of concepts like smart growth, low-impact development, and sustainable development, there evolved a greater focus on adopting policies that consider both growth and conservation simultaneously. As a result, new goals were developed to minimize runoff by infiltrating rainfall on site and to find uses for the water as opposed to utilizing storm drains. This study aims to address three major topics of interest: How urbanization has affected hydrology and water quality in Minnesota and the current BMPs used to mitigate those effects; the tools that local communities can use to apply these BMPs; and a case study on a specific project that utilized BMPs to educate the public. This study reveals that urbanization is increasing at a rapid rate in Minnesota which is increasing the amount of stormwater runoff which leads to decreased water quality. The current BMPs that have been developed are effective, but barriers exist that are prohibiting their implementation like high costs, outdated ordinances, and a basic lack of understanding. However, through the use of incentives, innovative regulations, and the creation of pilot/educational projects, local communities can effectively require and/or encourage developers to utilize stormwater BMPs on that site level rather than utilizing storm drains. An example of this is at the University of Minnesota Landscape Arboretum’s Rainwater Runoff Model. Here, a pilot/educational project has been built that clearly illustrates how urban, impervious surfaces negatively affect water quality, and how utilizing BMPs can tremendously improve water quality.