Project Description

The Imagine Jasper Avenue (IJA) Streetscape Improvement project located within the City of Edmonton, between 109 St and 124 St, is intended to create a vibrant ‘main street’. ISL was retained to develop the design concept, preliminary and detailed engineering designs, and monitor the construction of the streetscape improvements. 
To mitigate impacts on local sewer capacities, stormwater runoff was designed to route through Low Impact Development (LID) structural soil cells located below the sidewalk areas. Urban trees and other plantings were located within the structural soil cells to enhance the streetscape improvements and take up the local stormwater runoff. 
The redevelopment of the roadway provided opportunity for improved major drainage conveyance, with the upgraded roadway designed to have capacity to convey runoff expected during the 1:100 year design event. 
In addition, it was recognized that there was a risk of ponding on Jasper Avenue through a depression at 110 Street – the location of the previous railway underpass. A 2,000 m3 underground storage facility was designed to prevent roadway ponding at this location.

Challenges:

• It was difficult to prove that the deep combined trunk sewer system had capacity to receive discharges from the project corridor during a 1:100 year design event, which was essential to minimizing the size and costs of the proposed storage facility at 110 St.

Solutions:

• ISL worked closely with EPCOR Drainage to develop a better understanding of rain intensity distribution patterns of actual, measured large events. Computer simulation modelling allowed for the sizing and cost of the proposed storage facility to be minimized.