Streambank Stabilization Project

Project Description
Streambank erosion was undermining an old creosote timber retaining wall and the anchors for cables supporting the radar towers at CFRS Newport Corner. As a result, excavation and streambank stabilization was required for a natural watercourse flowing through the radar towers in order to stabilize the watercourse and prevent further erosion from taking place. The stream itself was found to be a trout habitat with significant brook trout populations.

Services Provided
Terrain Group was retained as a sub-consultant by Jacques Whitford Environment Limited to conduct hydrologic and hydraulic analysis in order to project maximum flow depths and maximum flow velocities for the proposed channel upgrades. This involved estimation of peak flows and runoff volumes for a total drainage area of approximately 1,100 acres. Flow calculations were based on a 24 hour design event with return periods ranging from 2 years to 100 years. Estimated peak flows for the 100 year return period were in the order of 500 cubic feet per second (CFS), or 14,000 litres per second. Once peak flows and runoff volumes were determined, an estimation of maximum flow depth and maximum flow velocity for three proposed channel upgrades were provided. Channel cross-sections were analyzed to estimate depth and maximum velocity based on open channel analysis. A variety of channel geometry options were examined, along with stabilization techniques.