Modelling low impact development in the Nose Creek watershed
Low impact development
Increased stormwater runoff from impervious areas is a major threat to the ecological health of urban streams and the sustainability of water resources. Low impact development (LID) is an approach to stormwater management that reduces the impact of imperviousness on urban watersheds. This study explored LID retrofitting on private lots to reduce runoff within Calgary's Nose Creek watershed. Six variations of a suburban lot scenario were designed by incorporating three low impact development practices: absorbent landscaping, bioretention/rain gardens, and rainwater capture. These scenarios were then modelled using the City of Calgary Water Balance Spreadsheet. The lowest rainfall runoff percentage (3.2%) was achieved by doubling the soil depth of absorbent landscaping. Further, capture and re-use of runoff from 5% of the impervious area would reduce indoor non-potable water use by 3.4m3. Future LID research into retrofitting costs, landowner acceptance, and hydraulic performance of existing private lot source controls is recommended.