Most water tables use a chamber in the bottom.
Bend a steel plate and put some notches on one end.
Weld it to the floor(notched end) and the other to the wall. this chamber will fill with water.
Put a pipe in about 1-2 inches below the top of the chamber. Add air to the pipe and it will force the water out the lower slots and raise the warter level. Vent the pipe and the water level will drop down.
Much simpler than piping and 55 gal drums.