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Author Topic: How can rivers be prevented from bursting their banks?  (Read 1403 times)

Offline thedoc

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Jenny Mant, from the River Restoration Centre, explains how we manage river levels and how we can stop rivers from bursting their banks...
 Read a transcript of the interview by clicking here
or Listen to it now or [download as MP3]


What can be done to reduce the risk of flood damage in future?  Interview with Roger Falconer, Cardiff University.
 Read a transcript of the interview by clicking here
or Listen to it now or [download as MP3]


What can cities do to reduce the risk of flooding? Professor Nigel Wright, from Leeds University, explains the Blue-Green cities project...
 Read a transcript of the interview by clicking here
or Listen to it now or [download as MP3]
« Last Edit: 12/03/2014 04:52:40 by CliffordK »


 

Offline CliffordK

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Re: How can rivers be prevented from bursting their banks?
« Reply #1 on: 12/03/2014 01:00:30 »
One of the worst (recent) floods to hit the Northwest USA was the Christmas Flood of 1964.

Apparently it had 3 factors.
Unusually cold December freezing the ground, causing later rain to run off rather than soaking in.
Heavy Snow on top of the frozen ground.
Heavy Pineapple Express Rain melting the snow and rain together.

I don't think the exact same conditions have recurred in the last 50 years. 

Other parts of the USA deal with hurricane rains that can dump several inches in a day.

In this area, our rainfall and snowfall is very seasonal, leading to most of the flooding in the winter and spring.  With the mountainous environment, most major river drainages have multiple hydroelectric dams.  By law they drain down the dams significantly during the winter to give a flood buffer, sometimes causing debate over holding water for winter or early spring floods.

However, I'm not sure how well the dams would deal with the 1964 flood, where in some places the Rogue river was 80 feet above normal, and still fast flowing.

Some of the things I've seen for river flood control.
  • Flood control hydroelectric dams
  • Design river banks so one bank is protected, while the opposite bank has open agricultural fields to allow flooding and the river to spread out
  • Build a secondary channel and flood control berms with the location of the berms set a significant distance from the river.  Use the area between the berms and the river for agriculture.

The western USA has fast moving flood waters, while the midwest has slow moving floods, that may take a week or so to travel between major cities.  Bottlenecks in the cities can be a problem, but allowing the flood waters to spread out before and after the bottlenecks can help a little.

Good points about silt control, more important in some areas than in others.
 
 

Offline Ophiolite

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Re: How can rivers be prevented from bursting their banks?
« Reply #2 on: 12/03/2014 06:45:32 »
Stop building on flood plains (the clue is in the name) and allow them to burst their banks.
 

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Re: How can rivers be prevented from bursting their banks?
« Reply #2 on: 12/03/2014 06:45:32 »

 

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