Optimizing the environmental co-benefits of Low Impact Development and Green Infrastructure in York Region

York Region and Lake Simcoe Region Conservation Authority will partner to design a methodology for optimizing the environmental co-benefits of low impact development (LID)/green infrastructure (GI) features. LID/GI projects generally target improvements to stormwater quality and quantity. This project will go beyond business as usual, by assessing co-benefits such as chloride reduction, carbon sequestration, urban biodiversity, air quality improvements, evapotranspiration and climate change adaptation. The study will recommend desktop methods for estimating co-benefits during the planning phase of capital projects. A monitoring approach will also be developed to evaluate each benefit and trade-off (for example, carbon sequestration versus reduced retention capacity). The study will focus on a planned road reconstruction on a stretch of Highway 11 from Green Lane to Simcoe County. This is an optimal site for the study because there is a significant amount of environmentally protected land near the project limits, including the Holland Marsh Complex and Source Water Protection areas. These areas provide drinking water to approximately 48,500 residents. The anticipated outcomes of the eventual capital project include removing an average of 80% of total suspended solids (TSS) from the project area over the long term. Beyond environmental benefits, the study will allow for longer-term life cycle cost projections, including operations maintenance. More LID/GI features could also mean more recreational amenities for the York Region, by creating more accessible natural areas for residents. This project aligns with York Region’s Official Plan, Transportation Master Plan, Sustainability Strategy, and Vision 2051, which all promote green corridors and air quality improvements. The study will support these objectives by enabling more integrated, standardized incorporation of LID/GI features in the planning and design processes for capital projects. Innovative aspects: By developing methodologies for quantifying and monitoring environmental co-benefits, this study goes beyond a standard stormwater management technical assessment focussed on water quality and quantity. This approach aims to increase the number of LID/GI features implemented in future York Region capital projects by removing current barriers (for example, cost, competing departmental priorities, and buy-in from leadership). Replicability: • The methodology that this study aims to develop can be used to support practitioners in assessing environmental co-benefits of LID/GI approaches, to achieve municipal buy-in for implementing these features • York Region will provide an educational workshop to transfer knowledge gained from the study to York Region senior management, council and staff (Project description from original funding application)