Only if there is a very large lake at the bottom. If that lake doesn't exist then you have to build it at great cost. You also lose a lot to evaporation if you do this.
Where "very large" is still a lot smaller than the water requirements for hydro generation.
The 3.6 GW Fenging pumped storage facility holds 53 thousand acre-feet of water. Lake Mead holds 28 million acre-feet of water to run a 2 GW generator.