Is there a way to use hydro electric power in a contained water source.. like... making a large tank reservoir, then making a spillway at the top, and several wheels to the bottom.. is this just a loss of power if I used pumps to return the water to its res.

Hydro power works on the principle of converting the gravitational potential energy of the water into electrical energy. In order for electrical energy to be produced, the water must end with less gravitational potential energy than it started. Therefore, it must leave the system at a lower altitude than it started. Pumping the water back to its original starting position does not meet this criterion. It will, as you said, be a net loss of energy (due to the fact that the system is less than 100% efficient). Unless there's a natural (i.e. not powered by pumps) in-flow of new water into the reservoir, you can't magically create energy out of it. Sorry.