WCW24

Many municipalities experience troubles with drainage crossing pedestrian walkways, creating maintenance and safety concerns, especially during freezing months. The neighborhoods of Donsdale and Carter Crest in Edmonton have experienced issues with water ponding and icy sidewalks in winter due to concrete swales between neighboring backyards collecting flows and draining them directly to sidewalks prior to overflowing to the treed boulevard and road gutter. Stantec was retained to design Absorbent Landscapes or other LID facilities to slow and promote the infiltration of flows conveyed by the concrete swales. This included designing a method of conveying the storm flows below the sidewalk and determining how to install the preferred LID facilities around existing obstacles including mature trees, Canada Post mailboxes, and utilities to minimize disturbance while maximizing the LID storage capacity. This project was completed on behalf of EPCOR Drainage and consisted of the conceptual and detailed design (complete) and support during/post construction (Fall 2023 and expected completion in 2024). Various locations experiencing ponding and ice issues were inspected and solutions were developed including Absorbent Landscapes, Bioretention Gardens, Soil Cells, Permeable Pavement, and grey infrastructure (i.e., catch basins connecting to the existing sewer). Fourteen locations were selected from the concept design to proceed to detailed design and construction. A method for flows to cross the sidewalk from the concrete swale outlet to the Absorbent Landscapes in the boulevard was developed and Stantec coordinated with the City of Edmonton Urban Forestry to construct the facilities around City trees to maximize LID storage while protecting existing tree roots. This presentation will summarize the LID locations and designs, some of the construction challenges and successes, and discuss the applicability of this stormwater management approach to other municipalities.