Differentiating young, old and relict fan surfaces was carried out initially by using QuickBird satellite imagery. Old and relict (flood free)
surfaces exhibit a darker tone due to the presence of more weathered
and sometimes varnished clasts, while younger (flood prone) surfaces
have a lighter tone due to exposure of relatively unweathered sediments and clasts, due to recent sedimentation. For each fan surface,
the drainage pattern, surface morphology, maximum depth of channel
incision, and weathering features (i.e. presence of rock varnish and relative degree of soil development) were recorded. Using a theodolite,
three topographic cross-sections (one for each fan) were prepared to
study the fans surface morphology.