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19 votes
Accepted

Do dams reduce the flow of river downstream?

Once a dam has been constructed in a river, the natural flow of water will be disrupted. You correctly state that initially there will be a period required for the dam to fill. Until then, little of ...
Fred's user avatar
  • 24.8k
14 votes

Do dams reduce the flow of river downstream?

You're correct that simply putting a dam in place, once its lake is filled, doesn't change the average flow downstream by more than a few percent (those few percent can be lost to increased ...
Semidiurnal Simon's user avatar
7 votes
Accepted

Is there a quick way to roughly estimate how quickly a flood will move downstream?

My first thought would be to use Manning equation as an approximation. It does not take into account the effect of a dam burst providing excess water and immediate flooding, although for larger scales ...
Rob's user avatar
  • 751
6 votes
Accepted

Why was the flooding in Derna, Libya so catastrophic?

I hesitate to write this answer as I am neither a metereologist, nor a hydrologist, nor a civil engineer with expertise in dams. From what I gather from news reports and available data, the proximate ...
njuffa's user avatar
  • 558
6 votes
Accepted

Was the filling of the Three Gorges Dam's impact on the Earth's rotation rate detectable?

One needs to calculate the change in the moment of inertia of the Earth and use conservation of angular momentum (the rotation period is proportional to the moment of inertia). Most of the water will ...
Keith McClary's user avatar
6 votes

Was the filling of the Three Gorges Dam's impact on the Earth's rotation rate detectable?

The .06 microseconds figure doesn't sound accurate The moment of inertia for a solid sphere is $$I = \frac{2mr^2}{5},$$ where $m$ is the mass of the sphere and $r$ is its radius. Applied to the Earth,...
kingledion's user avatar
  • 3,376
3 votes

Earthen dam with rock fill and clay core

Okay have a look at this article it may be some use, it's the Journal of GeoEngineering, Vol. 8, No. 1 April 2013 Pgs 27-32 so you may be able to get a hard copy if the link fails, it talks about clay ...
Ash's user avatar
  • 4,670
1 vote

How to deal with a pond silting up

Obviously removing the silt will increase the erosion along the banks of the pond(the neighbors will probably not like this). It sounds to me like this pond is badly constructed if the erosion is ...
trond hansen's user avatar
  • 1,886
1 vote

How to deal with a pond silting up

Cut a notch into the dam so the water drains to the level you want. The marsh will shrink to a smaller size.
haresfur's user avatar
  • 4,429
1 vote

How to deal with a pond silting up

That is what lakes and ponds do , fill with silt. Serious earth moving equipment is needed to slow Mother Nature. Our community has recently removed some silt with draglines, bulldozers , trucks , etc....
blacksmith37's user avatar
  • 1,043
1 vote

What current evidence is there for a Glacial Hudson River Valley deluge?

" Who's studied the glacial dam breaking South and having cleared the Hudson River valley, forming the Verrazano Narrows, NY Harbor, Staten and Long Island, and washing through to the Atlantic ...
Knob Scratcher's user avatar

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