On 05/08/2019 19:01, Terry Casey wrote:
In article , steve@walker-
family.me.uk says...


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.


Like a Chinook, possibly?

If the outlet were placed at the bottom of the dam, there would be a
decent head until the reservoir was virtually empty.


Sorry - only about 34 feet. Beyond that, you would just create
a vacuum in the pipe as the weight of the water exceeeds the
atmospheric pressure needed to push the water up the pipe.

I was assuming that the depth behind the dam was less than it actually
is. Today's report was that they'd got down to 8m below the top of the
dam, with another 8m to go. I didn't expect it to be quite as deep.

SteveW