After the alpha-cut is performed the potential extent of discharge is predicted over the area modelled. Consequently the effectiveness of the model is ultimately dependant upon alpha. It consists of a north aligned central ridge with numerous first and second order catchments draining east and west. The study area is approximately 4.5km by 2.5km. Elevation ranges from 440m to 540m.
Geology is granitic on the west side of the study area and sedimentary on the east.
The contact is about 200m to the east of, and parallel with, the ridge. Numerous intrusive dykes are aligned with the ridge and there are few depositional areas within the study boundary. The model was also run at the Mona Vale study site. The catchment dimensions are approximately 2.5km by 2km, and total area is 228ha. Elevation varies from 210m to 340m.