After experiencing major flood events in the past year, the City of Courtenay is looking to update its floodplain mapping and modelling to develop a long-term management plan.
The city is applying to BC Emergency Management for funding through the BC Flood Protection Program.
This funding would assist the city in addressing flooding issues related to the Puntledge and Tsolum rivers, Kevin Lagan, the city’s director of operational services, and Derek Richmond, the manager of engineering, explained in their report to council, which was received Tuesday.
“Significant flooding events have been able to bypass the Lewis Park structures and flow overland, causing property damage and interrupting transportation and emergency services,” wrote Lagan and Richmond. “The proposed initiative includes floodplain modelling and mapping, acquisition of approvals and design of any proposed works and construction of same.”
The proposed work would include a diversion barrier and ancillary works along the Old Island Highway in the vicinity of the Lewis Centre, according to Lagan and Richmond’s report.
“The modelling and mapping will allow the city to develop long-range plans for land-use and flood management,” they wrote. “It is anticipated that these results will also provide the basis for other flood protection measures in the vicinity of the Puntledge/Tsolum rivers.”
The funding application will be based on a three-way equal cost-sharing split between the federal and provincial governments and the City of Courtenay.
The city submitted a preliminary application for funding in June. The application was accepted as provisional, and the city has been asked to submit a more detailed application report.
The estimated cost of the initiative, including modelling, design and implementation, is $725,000. The city’s portion would be $242,000.
The first phase of the work — which is scheduled for 2011 — includes the modelling, design and approvals at a total cost of about $198,000, of which the city’s portion is about $66,000, according to Lagan and Richmond.
“Initially, we need to do significant study work on that, which would be to look at our storm drainage flood mapping, bring that mapping up to date — it was 20 years since it was last done,” said Lagan.
“We’ve seen some significant flooding over the last few years, and we want to take a look at the increasing height and flow of the Tsolum River, rising tides, increased storm surges and try to address these for future land use planning in the area as well as storm drainage enhancement works and mapping,” Lagan added.
The four flooding occurrences Courtenay had were, in theory, 50-year floods, noted Mayor Greg Phelps.
“So if we had four of them in less than a year, obviously our 50-year forecast is sort of off balance, and we have to look at all the various factors, such as what’s happened in the Tsolum watershed, which affect us downstream,” he said.
Over Christmas, water came through the Tsolum River at 277 cubic metres per second, which is the highest on record for that particular river system, noted Lagan.
After the Tsolum flows into the Puntledge at Lewis Park, they combine to form the Courtenay River, which sometimes spills over into Lewis Park on the east side of the river.
“The flood predictions are based on historical data, and you’re predicting 30 years out, 50 years out, so it’s very difficult,” Lagan said.
Coun. Jon Ambler welcomed the initiative.
“I think that the situation is so dynamic and has changed,” he said. “Time and time again, we’ll hear from people who say ‘I’ve lived here in the Comox Valley for 50 years, and it never floods’ or this never happens or that never happens.
“Never is a big sample set, and somebody could be 80 years old living in New Orleans and say the levee never breaks. History only takes us so far because the situations that produce historical events, they’ve changed ... so to invest in a survey of the current situation, I think, is money well-spent.”
writer@comoxvalleyrecord.com