Stormwater Management in Cold Climates: A Green Solution for Salinity Reduction

The escalation of extreme wet weather events driven by climate change impacts both the quantity and quality of water, putting communities with outdated infrastructure and limited resources at a disadvantage. The implementation of bioretention cells, bioswales, and check dams will mitigate the effects of extreme wet weather events in Dollar Bay, MI, a disadvantaged community located in the northern United States that receives a high rate of snowfall at 206 inches per year. Rain-on-snow events will affect Dollar Bay resulting in flooding during the spring snowmelt. Another issue cold-climate communities like Dollar Bay experience are high salinity levels in the watershed due to road salts used in the winter. The cells will be modified to reduce salinity in urban runoff through the addition of biochar and kaolin clay to the soil. The green infrastructure design, modeled using ArcGIS Pro, HEC-HMS, and EPA SWMM, will reduce 69% of runoff in a 100-yr storm event, and reduce the peak flow velocity by 66%. Bench-scale testing utilizing a soil mix of 2% biochar and 5% kaolin clay confirmed 100% salinity reduction. Overall, the stormwater design not only decreases the risk of flooding and salinity concentrations in runoff, but also implements green space and provides economic and societal benefits for residents, appealing to all aspects of the triple bottom line of sustainability.