Question about Hydro Electric Dams

[Rapidskies]

I've always wondered why you don't see dams built in close proximity. It seems the biggest negative for a Hydro-Electric dam is its effect on the land directly upstream and the users of the water downstream but once you build a dam why not build many in the same area?

I guess what I'm asking is what are the negative implications in building a group of dams one right after another (say within 200 yards of one another). Imagine if we built another Hoover Dam or 2 next to the existing one. I would assume the water removed from downstream use would be practically the same if they are built close together and there would be minimal effect on the land directly upstream because it is already dammed. Why don't we see this done?

 

[Eli]

That's a pretty good question, and I really have no idea!.....

It seems like doing so would maximize the use of available realestate.

 

[Engineer]

I don't know the answer, but I have wondered the same thing. I think that you would need "pressure" from a decent size reservoir to make it work correctly. So I would guess that you really almost need a "lake" size amount of water to make it function correctly. Anyone else?

 

[Howard]

Conventional dams convert the gravitational potential energy to electricity, I think.

 

[Engineer]

Originally posted by: Howard
Conventional dams convert the gravitational potential energy to electricity, I think.

i.e. Water pressure turns the turbine!

 

[91TTZ]

Originally posted by: Rapidskies

I guess what I'm asking is what are the negative implications in building a group of dams one right after another (say within 200 yards of one another). Imagine if we built another Hoover Dam or 2 next to the existing one. I would assume the water removed from downstream use would be practically the same if they are built close together and there would be minimal effect on the land directly upstream because it is already dammed. Why don't we see this done?

Because the dam gets its energy from the water pressure, which means the amount of energy produced is proportional to the difference in elevation between the level of the water before the dam and the level of the water after the dam.

If you had 2 smaller dams, you'd have to limit the drop of the first dam in order to install a second dam. And even then, the cumulative energy produced wouldn't exceed the power produced by 1 large dam.

 

[Eli]

Let's think about this though....

I think the dams would have to be designed for this in the first place.

You ever realize how much water is backed up behind a dam?... And then there's just a trickle(Well, realitivly) at the bottom.

It would have to be setup so there were multiple reservoirs... levels. I believe it is the deepness of the water(pressure) that imparts energy on it, so that is a necessity.

Each level would have to allow enough water to flow to keep things filled... It would get a lot more complicated. Maybe it's better to have 1 large dam than several smaller ones?

What is the limit for the distance apart they can be? Maybe it depends on geograpgy? I know there are a few on the Snake/Columbia river..

 

[Howard]

Originally posted by: Eli
Let's think about this though....

I think the dams would have to be designed for this in the first place.

You ever realize how much water is backed up behind a dam?... And then there's just a trickle(Well, realitivly) at the bottom.

It would have to be setup so there were multiple reservoirs... levels. I believe it is the deepness of the water(pressure) that imparts energy on it, so that is a necessity.

Each level would have to allow enough water to flow to keep things filled... It would get a lot more complicated. Maybe it's better to have 1 large dam than several smaller ones?

What is the limit for the distance apart they can be? Maybe it depends on geograpgy? I know there are a few on the Snake/Columbia river..

Instead of building many of them, why not just build one? In theory, you would get the same energy.

 

[Eli]

Originally posted by: Howard
Instead of building many of them, why not just build one? In theory, you would get the same energy.

Yeah, I guess that's the real question.

I think we could build more dams, just spread farther apart... but then disruption of natural systems becomes a concern...

 

[Engineer]

Originally posted by: Eli

Originally posted by: Howard
Instead of building many of them, why not just build one? In theory, you would get the same energy.

Yeah, I guess that's the real question.

I think we could build more dams, just spread farther apart... but then disruption of natural systems becomes a concern...

As natural resources such as coal, oil, etc. start to run dry and people have to do with air condition or their PC, watch and see how fast those lands are turned into big power plants!