Posted by: Vicki Burns | July 21, 2014

Wetland Restoration For Flood Reduction – – Is It Worth Doing? Hurricane Katrina May Give Us Some Answers

Over the last few weeks Manitoba and Saskatchewan have been plagued with summer flooding related to massive rainfall and already water-logged land. There has been a lot of talk about how to decrease the negative impacts of flooding in Manitoba by creating a bigger channel to drain some of the excess water from Lake Manitoba , ultimately into Lake Winnipeg. The problems of flooding around Lake Manitoba have been exacerbated by the diversion of some of the Assiniboine River flow into Lake Manitoba in order to decrease threats to Portage La Prairie and other communities downstream.
This approach of large engineered solutions is certainly useful for harm prevention to a great extent. However, it doesn’t help those upstream of the diversions and it doesn’t take into account drought resilience, decreasing transport of excess nutrients that are feeding blue-green algae in our lakes, or the water holding capacity of wetlands. A recent report from John Pomeroy of the University of Saskatchewan has determined that drainage of wetlands over the last 50 years on the Prairies has increased the peak flow during flood events by over 30% and that if we were able to restore wetlands to their level of several decades ago, it could reduce the peak flows by 25 % . Those are very significant numbers.

Satellite image of Hurricane Katrina, courtesy of NASA

Satellite image of Hurricane Katrina, courtesy of NASA

I am aware that there is some questioning of this approach and as yet, it has not been seriously embraced by decision makers who are controlling how our flood reduction $$ are being spent. So when I saw this news about wetland restoration around Lousiana and how it is being viewed as a key flood prevention strategy, I was impressed. We are all aware of the devastation Katrina brought to New Orleans. If they believe that restoring the wetlands in their area can help prevent future disasters, can we not learn from that?
The Manitoba government has recently proposed strong regulations to stop wetland drainage and that is terrific. Now we need to move quickly on developing a comprehensive plan along with Saskatchewan to restore wetlands. Large engineered solutions for moving water are one part of the solution but restoring the water holding capacity of our land is equally important.

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