Posted by: Vicki Burns | April 15, 2013

Warnings about Wetland Drainage and Increased Flooding From 34 Years Ago

image of green vegetation arund a marshy area

Wetland Holding Water

Recently I was searching the web for any information relating wetlands and drainage to increased flood severity. Its an area of particular interest right now as we await another spring flood in Manitoba. DUC(Manitoba) has done some excellent work on this issue, relating the drainage of almost 70% of our Prairie wetlands over the past century, to increased peak flows during floods and heavy rain events. Its well-recognized now that when the peak flows occur they bring a great deal of the phosphorus off the landscape and deliver it quickly into Lake Winnipeg and other lakes. There it stimulates the growth of blue-green algae that are threatening the health of our lakes.
I was very interested to find this paper “ THE ROLE OF WETLANDS IN PROVIDING FLOOD CONTROL BENEFITS” By Len Cernohous U. S. Fish and Wildlife Service, Bismarck Area Office, North Dakota December 1979. I was struck by the fact that 34 years ago there was recognition of the connection between wetlands and flood control, yet we seemed to have ignored this and now are dealing with the consequences of more frequent and more severe flooding. I certainly don’t want to diminish the contribution of climate change and more extreme weather events to flooding but I do think its time to get serious about taking action on anything we can to decrease the severity of flooding.
The final comments in Cernohous’paper are more apt then ever now.Its time for us to make serious and meaningful investments in wetland protection and restoration. “Whatever the flood reduction potential achieved by wetland protection, 2 percent, 10 percent, or 20 percent, the important point is that it is a percentage that man can control. We have no control over a rapid melt, spring rains or heavy snows, but we can control the impact of drainageand poor land use. By protecting existing wetlands, restoring drained wetlands, and practicing good land use, we can expect to gain a significant measure of flood control and reduce the escalating economic losses.”


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