Btw acre-foot = 43,560 square feet 1 foot high [43,560 cubic feet]
A cubic foot of salt water weighs 64.1 lbs
A cubic foot of fresh water weighs 62.4 lbs

So if you a pipe which has volume of 1 cubic foot per foot and it's a 1000' long, with salt water this water weighs:
64,100 lbs
And fresh water weighs 62,400 with difference of 1700 lbs and if divide by 144 sq inches you get a psi of only 11.8.

Hmm, that doesn't work as well as I thought it would. If the pipe was 10,000' you would get 118 psi. Though not many places with 10,000' of ocean.

You if you had a pipe filled with fresh water the differences in weight would force the fresh water upwards [and if took the salt out the water at the bottom it would continue pushing the water up].

But wait a minute, you should have that 118 psi at the top of the pipe, oh yeah and also 118 psi difference at the bottom.

But you do have a lot pressure at the bottom, and it should some difference in the pressure if the tap at top is opened a little bit or wide open.
Another aspect is one could make the water in pipe weigh less- if half it's volume was air than it weigh half as much- thereby giving more difference in pressure at the bottom of the pipe.
What happens if you combined mining methane Hydrate with water desalination?

Water in in Great Salt Lake weighs from 69 to 76 lb per cubic foot. And is as deep as 1000' and gives at 70 lbs, it gives 52 psi in 1000'.

Anyways there should somehow this could work and preferable in less water depth, like in ballpark of 3000-4000' so aren't limited in areas of just deep water [of course, deepest water in the world is around 39,000'].