Futurology

Dams have major ecological impacts. Water towers could work but as I understand it storing heat in sand or salt is more energy dense/efficient vs elevated water and gravity. All of what I just said is based solely on things I've read some time ago but cannot cite, and documentaries about dams

A Swiss company is trying this, though using concrete instead of water. Wear and tear and moving parts are disadvantages though.

https://www.swiss.tech/news/giant-gravity-batteries-storage-renewable-energies

This has no moving parts compared to water storage which requires pumping, and you’re describing hydroelectric power that requires building of dams or levees. Reservoirs are inefficient, have issues with evaporation, and basically flood habitat.