• Effectiveness of Low Impact Development Design in Poorly Draining Soils in BC’s Lower Mainland

  • Project Components:
    Conference Presentation, Design, Stormwater
Effectiveness of Low Impact Development Design in Poorly Draining Soils in BC’s Lower Mainland
2016 Salish Sea Ecosystem Conference

KWL's Sara Pour gave a presentation at the 2016 Salish Sea Ecosystem Conference in Vancouver, BC.


Kerr Wood Leidal (KWL) has designed, constructed and monitored low impact development (LID) designs across the Lower Mainland of British Columbia. This presentation focuses on the findings of monitoring programs at three new construction residential sites: Silver Ridge Development in Maple Ridge, East Clayton Development in Surrey, and Routley Neighbourhood in Langley. Conclusion will be drawn on effectiveness of LIDs in till and clay soils, their ability to meet stormwater targets in the Lower Mainland, and their performance over time.

The Silver Ridge residential development in Maple Ridge consists of roadside bio-retention rain gardens and disconnected roof leaders to absorbent amended soil layer and infiltration rock pits.  Continuous flow, rainfall, groundwater levels, and runoff water temperature data were collected for three years following the development of the site to evaluate the performance of the LIDs with a particular focus on volume reduction.  Recently, eight years after installation of the LIDs, water quality data was collected to evaluate the effectiveness of these mature bio-retention facilities at treating typical pollutants in urban stormwater runoff. At East Clayton residential development in Surrey, KWL monitored flow and groundwater levels for three years. For this neighbourhood, the effectiveness of disconnected roof leaders and infiltration trenches in clay soils is evaluated.  Lastly, KWL monitored flows in the Routley Neighbourhood in Langley for eight years.  The data is used to compare the flow response between an area that has implemented LIDs (disconnected roof leaders, on-lot infiltration galleries, greenway swales, and base flow diversions) and an area with traditional stormwater conveyance systems. 

The operation of the monitored LIDs is compared with stormwater criteria outlined in Fisheries and Oceans Canada’s Urban Stormwater Guidelines for the Protection of Fish and Fish Habitat.  Conclusions are reached on performance of LIDs in poorly-draining soils both in saturated and unsaturated soil conditions.

SW3F_Pour_SalishSea2016_SourceControls1.pdf (application/pdf, 8.359Mb)