The similarity of the results is due to the dominance of upness . See Figures 6 -9. To improve the model requires an increase in complexity. FLAG is intended as a rapid appraisal tool, and any improvement could be outweighed by the cost of its application. The variations in the results are largely due to the different landforms of each catchment, which are due to geology, and this difference reflects the variety of discharge factors present in the landscape.
Alpha is only valid for the landform in which it has been calculated.
Also, the Tout Park study site contains less depositional areas than the Mona Vale site. The results for Tout Park were better than at Mona Vale primarily because there is little depositional material within the study area. Also the local relief at Tout Park is greater than at Mona Vale and has trained a to more concave values. At Tout Park the effect of the north oriented intrusive dykes has been differentiated by the model. The surface expression of these features is to constrict the gullies, creating bottlenecks that the concavity filter has differentiated and local depressions discriminated by the lowness filter.