Implementing a neighbourhood scale stormwater retrofit : effect of self-draining rain barrels on an urban stream

Over the past 50 years, as North America has become more urbanized, extensive research has been done to understand the impact of urbanization on the hydrological cycle. Specifically, land development is known to significantly alter the hydrological cycle and consequently the aquatic habitat by increasing the magnitude and frequency of flooding events, by increasing storm flow flashiness and by altering base flow regimes in streams. The current approach to mitigating the negative impacts of land development on receiving streams involves decentralized treatment of frequently occurring rainfall events at the source in other words on-site stormwater management. Stormwater practitioners and researchers have identified the need for pilot scale research projects to improve the current understanding of on-site stormwater management techniques. The objectives of the current study were to determine the level of effort and methods required to gain volunteer participation for on-site stormwater management retrofit projects as well as to determine if retrofitting single family lots on a neighbourhood scale can have a an effect on the hydrological response of the receiving stream. The objectives were achieved through collaborating with the City of Burnaby, to plan and implement a pilot project in two residential neighbourhoods in the Beecher Creek Watershed. It was hypothesized that with the cooperation of the municipality, sufficient landowner participation (at least 30% of the study area residents) could be gained through door-to-door meetings with residents and through offering incentives for participation in the study. It was also hypothesized that retrofitting the houses in the study area with self-draining rain barrels that detain roof runoff could have a regulating effect on the stream response. Two sub-catchments in the Beecher Creek watershed were chosen as the sites of the study and flow-monitoring stations were set up at sub-catchments’ outfalls. A communication strategy was developed and executed over a seven-month period that resulted in participation of 26 (out of 77 possible) residents. Overall, 40 rain barrels were installed to capture the runoff from about 3.5% to 7% of the catchment area. Analysis of the initial collected data indicated that the rain barrels had a regulating effect on the stream response.Applied Science, Faculty ofCivil Engineering, Department ofGraduat