Flood mitigation plans for the Willow Estates area east of Drumheller Valley Secondary School (DVSS) were revealed during a virtual information session hosted by the Drumheller Resiliency and Flood Mitigation Office (DRFMO) on Thursday, March 31.
The community was affected by flooding in both 2005 and 2013 and, along with the risk to homes in the area, there is also risk to vital infrastructure-the town’s main water supply lift station.
“In 2005, there was some temporary fill brought in for flood protection,” Woods Water Resources senior project engineer Liv Hundal explained during the presentation. “We want to minimize that kind of emergency response, especially from more frequent flood events.”
The berm will be about 710 in length and will ring the community of Willow Estates with three main segments.
This design will help protect the community from direct flooding from the Red Deer River and offer protection against back flooding from a drainage gully within the community.
Some 45 existing properties will be protected along with future development of some 20 properties.
One unique feature of the Willow Estates berm is it will not encroach on private property. However, some work must be undertaken within the river channel to install about 50 metres of rock riprap upstream and roughly 100 metres of riprap downstream.
“Ideally we do try to avoid encroaching into the river, but sometimes it is necessary to place this rock riprap to prevent erosion,” Mr. Hundal explained. “We only do this work after careful consideration and make sure we are not causing any adverse impacts on adjacent areas or our fish habitat.”
The berm design will still allow for public access to the riverbank at the southeast portion of the berm, along with swift water rescue access near the pumphouse at the west end of the berm.
Some trees in the area will need to be removed, and an initial tree assessment has been completed. Trees assessed at good to fair condition will be replaced with five trees, shrubs, or a combination thereof for each tree removed. The berm will also be landscaped with a low maintenance native seed mix.
Regulatory submissions will be underway in early April and, pending regulatory approvals, tendering is expected to go forward in June to July.
Construction is anticipated to begin in September 2022 with completion expected by the end of 2022.
