Blogs > Climate change and Global Warming > Why Rivers Flood – and How to Reduce Risk

Posted by Susan Sharma on May 24, 2011

.............very high amounts of rain, snowmelt, or both lead to floods. All the land that drains downhill into rivers—or into the streams and tributaries that eventually join the river—is called a watershed. When that watershed receives a lot of rain, the river will rise higher than its banks and spread out into the floodplain, which is the name for low lying areas along a river.

But what most people don’t realize is that floods are not some departure from the way a river is “supposed” to behave – witness the common description in the press of a river “bursting from its banks” during a flood, like a convict breaking out of jail. The river and floodplain are actually one single highway for moving water downstream (and not just water, but also sediment, which is why the Missouri River is nicknamed the “Big Muddy.”) It’s just that the floodplain part of this highway is dry much or most of the time...............

....on average, natural rivers will spread out onto their floodplains anywhere from once a year to once every 3 years....Floodplains themselves are part of the solution............
Strategic designation of such floodways, with policies that compensate people who live within them, can be critical to reducing the damage of massive floods. We also need to make these floodways more “flood-proof.” For example, there may be ways to develop crops that are more tolerant of floodwater. ......Read more at

http://www.nature.org/ourinitiatives/habitats/riverslakes/why-rivers-flood-andhow-to-reduce-risk.xml

or at

http://tinyurl.com/4y6as9s
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