When development is completed, residents of Harmony, located in Rocky View Municipal District west of Calgary, will have a brand new 59-hectare lake around which to cluster their new community. That same lake will be the source of their drinking water. Thus, we are taking extra care to protect that lake source from degradation. A key part of that effort will be constructed wetlands that remove harmful pollutants, such as sediment, oils, and nutrients like phosphorus and nitrogen, from runoff that enters the lake. These pollutants are washed off during rain and storm events from hard surfaces such as street pavement, driveways and roofs. In the first stage of building Harmony, approximately 35 hectares of land will be developed. Urban Systems has designed three constructed wetlands, one an innovative subsurface design, to be among other critical best management practices in the Stage 1 development area that will help protect Harmony Lake.
When completed, the constructed wetlands will fit well into the proposed low density residential Phase 1 area, providing aesthetic and wildlife appeal to the community, while also treating runoff. Two of the wetlands will have a diverse mix of open water areas, including deep pools and shallow areas with dense vegetative growth, and dry areas that become flooded during large rain storms. Treatment is provided by settling in open water, filtering through soil and uptake by vegetation. The third wetland, called a subsurface gravel wetland, also relies on filtering and uptake, but provides added nutrient removal within the subsurface gravel layer; it does not have permanent open water areas.