Alberta floods have permanently altered Rockies, foothills, rivers

While the flooding in Calgary and other communities in Alberta has, at the very least, temporarily changed the lives of many people in the province, the surging torrent of water that coursed down out of the mountains has permanently changed the landscape, so much so that some plants and wildlife may now be endangered and current maps are likely useless for future flood predictions.

This is the word from Professor John Pomeroy of the University of Saskatchewan, who is the Canada Research Chair in Water Resources & Climate Change, and director of USask's Centre for Hydrology.

"Even if the climate stayed exactly the same and we just had regular precipitation events in the future, the way the watersheds translate rainfall and snowfall into streamflow is going to be different now," Pomeroy told The Canadian Press from a research station near Canmore, AB.

"The channels are different. The curves we use to figure out the height of streams are different," he added. "They need to be remapped."

[ Related: Efforts turn to cleanup and recovery after Alberta flood waters recede ]

This news is particularly alarming given recent studies that show how flooding is going to become more common as our climate warms, and this flooding is going to affect more and more people.

"We estimated the change in population exposed to flood by overlaying simulated flooded area onto global population data. Flood exposed population was projected to be increased significantly following global temperature rise," said study co-author Dr. Dai Yamazaki, a researcher at the University of Bristol who studies global-scale river and floodplain modeling.

"Adaptations to flood risk change should therefore be made before the increase trend in flood risk becomes significant," Yamazaki said in a press release.

Pomeroy agrees, according to The Canadian Press article:

Alberta should build flood walls along the Bow River and manage its reservoirs for flood control as well as power generation, Pomeroy suggested. He said it was just luck that some reservoirs upstream from Calgary were unusually low and were able to hold back some of the water.

The province also will have to rethink what it considers developable land, said Pomeroy. The location of some developments in the Bow Valley are actually built on flood plains, something he calls "absurd hubris."

"This is Pacific Northwest U.S. weather we're getting and we're not built for it. We didn't design our cities, our floodways, our flood maps, anything for this," Pomeroy said.

It's not just the rivers and streams, though. According to Pomeroy, the mountains themselves have been changed by the massive flux of water — something he personally witnessed at a mountain not far from his research station.

"A side of it sloughed off and a large section created a debris flow 50 metres wide through a little creek you could have jumped across," he said in the interview.

"The Rockies have changed from this. They're even going to look a little bit differently."

Wildlife is also at risk, as during the interview, Pomeroy pointed to an example from back in 2011, when a buildup of water in the Spray Lakes Reservoir had to be released into the Spray River (one of the Bow River's tributaries), resulting in a "complete kill off of the trout in that river. They were wiped out."

A dedicated recovery plan put into place later that year helped the trout population in the Spray River to recover. However, apparently with the Bow River, the problem is the amount of silt that the water transported, which may have completely covered over the pebble-strewn ares of the riverbed that the trout need to spawn.

The flood waters can have a devastating effect on trees and plants as well, not only washing away or changing the nutrients in the soil, but also introducing chemicals, fuel and raw sewage washed downstream from cities and towns affected by the flood, but submerged plants can drown and tree branches under water for even a few days can die, weakening the tree and making it more vulnerable to other stresses, such as chemical contaminants, diseases and insects.

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One more-immediate concern for people in the flooded regions though, in addition to trying to get their lives back on track, is that all the standing water left behind by the flood will be a veritable breeding ground for mosquitoes. Some were already calling it 'mosquito mayhem' in Calgary, and that was before the flooding hit, and whereas mosquitoes can just be a nuisance, some — 3 species out of the 44 found in the province — are known to carry the West Nile Virus. Getting bit by a mosquito is no guarantee that someone will get the virus, or even that they'll get sick from it if they do. However, apparently 1 in 5 people develop 'West Nile Non-Neurological syndrome' (or 'West Nile fever'), coming down with a fever, severe headache, body aches and possibly a rash, and some can even develop a more severe illness called 'West Nile Neurological Syndrome'.

You can protect yourself by dumping out any standing water you see left over in containers, by wearing long-sleeve shirts and long pants when outside during early morning or late evening (their peak 'biting' period), and using a mosquito repellent with DEET.

(Photo courtesy: Jonathan Hayward/The Canadian Press)

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