Jun 19, 2008 11:00 pm US/Central
Good Question: Are We Making Flooding Worse?
(WCCO)
More and more communities along the Mississippi River and its tributaries continue to experience flooding. Obviously floods are caused by too much rain in a short period of time. But what impact does mankind have? Are we making floods worse than they should be?
"Absolutely yes," responded Dr. Chris Paola, Director of the National Center for Earth Surface Dynamics. Paola works at the St. Anthony Falls Laboratory as part of the University of Minnesota.
"A wild river is actually a difficult thing to live with, in the same way that a live animal or a wild ecosystem maybe difficult to live with," he said.
At the lab, crews are currently building a replica of a stream in order to study better ways to control flooding and reconstruct waterways.
"We'll be able to create floods. We'll be able to watch how the stream evolves. We'll be able to test out different methods for managing streams," he said.
Paola claimed the stream is the first of its kind.
"Flooding is a natural process," he emphasized, but that process is changing because of unnatural modifications to the land.
"There are a whole variety of small changes, which were made for good reasons, that altered the landscape contributing water and sediment to the river," according to Paola.
He points to the expansion of hard surfaces, like pavement and buildings, which force rain water to run into waterways almost immediately. But it's not just about urbanization. Paola said that the filling in of wetlands in rural areas and the overplanting of crops are also major factors.
"Every one of those small changes in itself may not cause a flood but the aggregate, the sum of all those changes, can drastically change the time that it takes water to reach from when it first falls on the land to the channel," said Paola.
To mitigate flooding, the land needs to act as a sponge, he said, slowly allowing rain water to trickle into waterways.
"Are we flooding more severely than we were 100 years ago, or are there just more of us living on the river, and we get upset when it floods?" asked WCCO-TV reporter Jason DeRusha.
"I'm an academic and I'm going to give you an academic answer. Yes. And yes," responded Paola.
"The peak floods are increasing; increasing in size and increasing in frequency. And that seems to be related to the fact that basically we've changed the land so if the water runs off the land more quickly and it reaches the river faster," he said.
Paola suggested that we need better management of the river. In some countries, political decisions have been made to let some less-populated areas flood to protect larger populations.
"We could have floods that were a little bit less severe, that were a little bit more predictable. We could soften the impact," he said.
(© MMIX, CBS Broadcasting Inc. All Rights Reserved.)
Click to enlarge
Stumble It!
Reporting
