Yes to part of that, and meh to another part. ;)

Closed loop, off river pumped hydro puts a couple of reservoirs 400+ meters vertical apart off of rivers or streams. As a result, all they need is vertical, they don't have huge reservoirs — trading h for m in mgh —, they don't impact biospheres and they are lower risk over all.

But there's no need to use salt water. It's just horrible stuff to keep machinery working in. Closed loop off river with high head heights just moves the same water up hill and back down again. A little bit of annual top up for evaporation and life is good.