December’s storm that wreaked havoc for a couple of days was the largest-ever flood to hit Courtenay.
A Flood Management Study has presented a number of options to mitigate future flood risks. One is a flood wall, which would cost about $750,000. Another — a ring dike around the Puntledge Road commercial area — would exceed $5.8 million. The former would offer a medium-term solution over 20 to 50 years, Mark DeGagne of McElhanney Consulting said in a presentation to Courtenay council Monday.
The Fifth Street Bridge and several roads were closed during the Dec. 9-11 storm, along with the Lewis and LINC Youth centres, and the Airpark. Homes and businesses near the Tsolum, Puntledge and Courtenay rivers were evacuated.
A boil water advisory was issued due to elevated turbidity levels in Comox Lake and the Puntledge. Initial estimates indicated the storm caused about $140,000 worth of infrastructure damage.
Previously, storms on Nov. 15, 2009 and Jan. 11, 2010 caused more than $130,000 damage to city-owned properties in the Puntledge commercial area.
The Tsolum River Floodwall project, which DeGagne described as a “small, protective structure,” was not eligible for grant funding in 2012 because it could not meet requirements to provide protection to a 1:200 (one in 200-year) flood event. The ring dike option was designed to mitigate larger, less frequent floods. DeGagne said it is possible for a dike to fail, in response to a question from Coun. David Frisch. Dredging the Courtenay River won’t help, he added, responding to Erik Eriksson’s query.
DeGagne said studies indicate that deforestation has minimal impact on storms of this magnitude. Regarding BC Hydro’s practice of spilling water, he feels the company “did the best they could under the situation.”
The Integrated Flood Management Study cost about $320,000. Roughly $155,000 was recovered from a government grant.