Analyses by Piotrowski demonstrate that the annual production of water from one typical catchment of would normally drain through its associated tunnel valley in less than 48 hours. The debris found in tunnels and at the mouth of tunnels tends to be coarse rocks and boulders – this is indicative of high flow velocities and an extremely erosive environment. This erosive environment is consistent with creation of tunnels over deep and wide, as have been observed in the Antarctic. Piotrowski's model predicts a cycle as follows: