On 04/08/2019 20:30, Steve Walker wrote:
On 04/08/2019 20:20, NY wrote:
"Tim+" wrote in message
...

Why not syphons?Â* I mean, pumps use power, quite a lot of it and are
relatively expensive. For a syphon, you just need a suitably sized
bit of
pipe.

I suppose they would still need a pump to "prime" the syphon, and it
would have to remain "in circuit" afterwards, because would be very
difficult to remove safely when there's a lot of water flowing, and an
unpowered pump may significantly reduce the possible flow rate.

You can start a syphon by placing the whole pipe in the water, letting
it fill, closing a valve on the end, lifting the end over and down and
opening the valve. A job for a mobile crane.

You probably don't want to be driving a mobile crane on the top of the dam.

Yes it *could* be done with a Chinook and a lot of men on top of the dam.

In the big scheme of things, fire engines have the pumps and hoses and
experienced staff. A few thousand gallons of diesel is neither here nor
there.