The reservoir is fed from the Todd Brook, a stream which has a catchment area of around including the moorland on Shining Tor and farmland around Kettleshulme village. Water enters the reservoir on its north bank via a small waterfall. The first several inches of water do not flow into the reservoir but flow down the reservoir's run-off into the River Goyt. The reservoir often receives little or no inflow during periods when rainfall does not allow the level to exceed the barrier, and this often affects the reservoir's water level, particularly in the summer months.