Monitoring of a Rain Garden in Cold Climate: Case Study of a Parking Lot near Montréal

Abstract

Poor stormwater management is one of the primary factors behind the environmental degradation of water bodies. As a result, best management practices (BMP) and low-impact development (LID) have been implemented and promoted in many cities. This study presents some interesting results from a 1-year monitoring program for a rain garden located at a car park in Longueuil, Quebec, Canada (near Montréal). The design was specific in nature as it combines a perforated underdrain, an internal water storage zone of 0.97 m, an almost impervious surrounding soil, and a flow regulator at the outlet. A monitoring program was conducted to assess the performance of the rain garden in warm and cold conditions. Inflow volumes were estimated with an SCS method using precipitation data, but runoff resulting from snowmelt was not monitored. Outflow rates were directly measured. Results from this monitoring program showed that the bioretention system retained