A Manitoba hydrologist with 30 years of experience says extreme precipitation, rather than drainage, caused this year’s flooding on the Assiniboine River.
Eric Blais, who works for an engineering consulting firm in Winnipeg, said the debate over drainage in Sask-atchewan and whether it causes flooding misses the point.
Flooding will occur If 150 millimetres of rain falls over a wide geographic area on soil that is already soaked, he added.
“If you’re in a very wet climatic period and all the storages (on the land) get used up, all bets are off,” Blais said.
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He said there’s no doubt farmland drainage changes the hydrologic regime and reduces the amount of water stored on the land.
“(But) when you’re talking about these really, really extreme hydrologic events, I don’t think you can point the finger solely at the producer.”
John Pomeroy, a University of Sask-atchewan water expert, released a report this summer on the Smith Creek in eastern Saskatchewan and how the loss of wetlands increases flows in the creek.
Blais said wetlands are a factor, but flooding occurred on the Prairies before the arrival of the backhoe and drainage plow.
“One of the largest floods on the Assiniboine was in 1888,” he said.
“Same, the biggest flood on the Red (River) was in 1826, before there was any drainage.”
