The provincial map that delineates flood zones does not identify areas near mountain creeks as at risk in the future for flooding.
The issue of the map for the community of Canmore came up at an information session held July 22 by the provincial government. Many residents expressed concern about the flood identification program from the province, which maps flood zones and flood fringes for the Bow River and the channel of Cougar Creek, but not the homes that run alongside it.
David Ardell, Alberta Environment and Sustainable Resource Development executive director of operations and infrastructure, explained the map looks only at flood ways and flood fringes for a one in 100 year event, or a flood event that has a one per cent chance of occurring.
“So we looked at the one in 100 year or one per cent chance mapping, what would be that number and how would that look on the landscape and that is what that map reflects,” Ardell said. “This last event was obviously much greater than that; we are not sure what the number is and the primary issue is of erosion.”
He said the province will carefully examine all the information about what happened across the southern part of the province in June and use that information to update maps and plans. In particular, Ardell said, the province will look closely at mountain hydrology issues and how it affects the flood mapping program in cooperation with the municipality.
The maps were an issue as well at the second meeting of Canmore’s flood recovery committee last week.
“We believe it is mapping from the ’94 era and it has not changed historically for Canmore,” said Chief Administrative Officer Lisa de Soto. “There are broad areas that flooded in Canmore that are not identified as floodway or flood fringe in the mapping.”
Mayor John Borrowman said the fact the map does not identify alluvial fans related to mountain creeks as flood risks is not a concern at this time. He said the map can be updated once information about the flood risks along creeks is better understood.
The Town of Canmore recruited consultants for an expert review panel to look at the 2013 flood event and conduct a risk and hazard assessment of mountain creeks in the valley. Borrowman said he expects the details that come out of that work to be included in the map, something echoed by provincial officials at the Monday night meeting.
“I think the work we do will inform changes to the map,” he said.
MLA Ron Casey said the flood risk in alluvial fans is different from the risk a river presents with overland flooding.
“The alluvial fan is not a flood plain, so again they have a risk factor involved, but not the same as construction on flood plains and as far as I know that was really the intent of the mapping; to look at high risk areas where floods were occurring,” Casey said. “Just because it isn’t mapped doesn’t mean it isn’t a risk.”
However, there are implications for future development as a result of the hazard map.
Because homes along Cougar Creek were not labelled as being in the flood zone, eligible owners can rebuild with disaster recovery funds and still be compensated in the future if another event occurs. It also means there are no provincial funds for relocation available to homeowners.
But homes in the flood zone, particularly South Canmore, that apply for recovery funds will have to put in mitigations otherwise they will not be eligible for future funding.
There are also two projects slated within the flood areas of the map – the expansion of the wastewater treatment plant to include a waste transfer station and material recycling facility and expansion of the Bow River Lodge.
“I think we have to consider flood proofing the new wing,” Borrowman said of the lodge expansion. “The Town (of Canmore) will talk about changing our own building requirements in these areas and with our own projects.
“We are going to lead the way with building flood smart.”
