Low Impact Development and Bioretention Areas in Cold Climates

Low impact development (LID) is growing as a stormwater management (SWM) practice in more temperate regions, with focus on ecosystem management to preserve local water balance and quality, by mimicking the natural predevelopment hydrology by use of Integrated Management Practices (IMPs). However, in colder climate the performance of LID based IMPs are to a large extent unknown. Cold climate regions require SWM solutions that address winter runoff conditions where low temperatures and repeating cycles of frozen ground, snow cover, rain on snow, snowmelt, and refreezing are experienced. In a harsher, cold climate environment solutions designed for summer conditions often fail to operate satisfactorily or completely shut down during the winter months. The main goal of this research is to test the performance of a bioretention area, an IMP structure, in a cold climate. A test size bioretention area is being built at the Risvollan urban hydrologic monitoring station, which is located in the city of Trondheim (N63° 20', E10° 18'), Norway. The performance of the bioretention area will be evaluated based on peak runoff reduction, detention capabilities, and reduction of total suspended solids (TSS), copper, zinc, and lead in the outflow. The Risvollan station has been collecting high quality hydrology and hydraulic data on a 2 min. time step since 1986, This represents a unique data base for which to compare and complement data for the field work.