Options to consider Flood mitigation official says government wants to work quickly on projects but won’t be skipping steps
The Alberta government is promising not to cut corners on future flood protection projects, but it also wants to work quickly before the next big event arrives.
“We will be doing all the required regulatory work accompanying any project like this,” Cathy Maniego told the Bow River Basin Council’s annual meeting in Calgary June 11.
“We are looking to see what we can do concurrently and we are looking to see what we can do quickly, but we are definitely not skipping steps.”
Maniego works with the flood mitigation and recovery program that works under the umbrella of Alberta environment and sustainable re-source development. Various proposals are moving forward to manage future floods and droughts.
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Most recently, the province and TransAlta Corp. agreed to initiate a pilot project to keep the Ghost Reservoir west of Calgary at its minimum water levels until the end of July. The reservoir could reduce risk to those downstream if it can capture high water flows.
TransAlta has estimated that the peak of the 2013 flood could have been as much as 25 percent higher than observed in Calgary and as much as 45 percent higher than experienced in Canmore without its storage facilities, which are normally used for electricity generation.
The province is also considering building off-stream storage near Calgary at Springbank and a dry dam west of the city at the confluence of the Elbow River and McLean Creek.
A Highwood River diversion to bypass the town of High River is under consideration with three options.
Another possibility is an underground diversion tunnel within the city of Calgary that could cost as much as $500 million.
The public has also said it wants better forecasting.
Earlier this year, the government contracted Hydrologics Water Management of Maryland, which uses real time data, advanced forecasts and computer simulations to develop possible scenarios in the South Saskatchewan River basin.
“These are statistically based forecasts. They do not include meteorology. You cannot forecast meteorology terribly effectively for three months out,” said company president Dan Sheer. “There is no way to guarantee you will never be flooded.”
He said the probability of extreme events this year is higher than normal but not extraordinarily so because the predictions are based on statistics. They look at the depth of the snow pack, which is higher than normal this year, and stream flows and predict the likelihood of certain events based on current conditions and past events.
For example, analysts know that the Calgary region typically receives the most rainfall and snow melt between May 15 and July 15.
The work produced 27 potential stream flows between now and three months out. Based on these models, water managers are able to make better decisions as they try to control stream flows and lessen damage.
Damage can occur when rivers are flowing at 500 cubic metres per second. Last year, stream flows were more than 1,700 cubic metres per second. If a flood similar to last year’s is expected, operators may decide to start holding back water upstream in storage to reduce the flow.
The company is also working in the Red Deer watershed to combine projected land use models with hydrologic models for long-term decisions and water supply forecasting.
“These tools need to evolve to reflect the current conditions, just like they already reflect current snow pack and antecedent flows,” Sheer said. “They should also reflect the land use conditions.”
These forecasting systems should eventually be expanded to all Alberta if funding is available, he said.
