The "Dambuster Run" is flown over the Ladybower Reservoirs, slightly north west of Sheffield. These are the dams that 617 Sqn. practised over before the Dams Raid.
Look on Gurgle Erf, and follow the A57 road out of Sheffield towards Manchester. The 'top' dam, Howden Reservoir, is the actual one used, for its likeness to the targets in Germany.