We have redone the figure 2 and added explanations on the process (see reply to comments on figure 2). Figure 8 should now be easier to read The surface drainage network line dataset was indeed based on the simplified (n=130) network following the following approach: Small segments with less than 10 nodes were automatically removed in SKUA (Paradigm/Emerson Trademark) and one iteration of smoothing was applied that further removed small irregularities without changing the overall orientation of major drainage lines.
Results appear to be sound and supported by the illustrations.