Analyzing the connectivity potential of landscape geomorphic systems: a radar remote sensing and GIS approach, Estufa Canyon, Texas, USA

摘要

Connectivity is considered one of the fundamental aspects that influences the rateof mass movement in the landscape. The connectivity aspect has been acknowledgedfrom various conceptual geomorphic frameworks. None of these provided adevelopmental methodology for studying the connectivity of geomorphic systems,especially at the scale of the fluvial system. The emphasis in this research is placed ondefining variables of the geomorphic systems that influence the connectivity potential ofthese systems. The landscape gradient, which is extracted from the Digital ElevationModel (DEM), and the surface roughness, which is extracted from radar images, areused to analyze the connectivity potential of geomorphic systems in the landscape.Integration of these variables produces a connectivity potential index of the variousgeomorphic systems that compose the fluvial system. High values of the connectivitypotential index indicate high potential of the geomorphic system to transport masswhereas the low values indicate low potential of the geomorphic system to transportmass in the landscape. Using the mean values of the connectivity potential index, the geomorphic systems in the landscape can be classified into geomorphic systems of lowconnectivity potential, geomorphic systems of intermediate connectivity potential andgeomorphic systems of high connectivity potential. In addition to the determination ofthe relative connectivity potential of various geomorphic systems, the connectivitypotential index is used to analyze the system-wide connectivity.The ratios between the connectivity potential index of the upstream geomorphicsystems and the connectivity potential index of the downstream geomorphic systemsdefine system-wide connectivity in the landscape. High ratios reflect the high potentialof the upstream geomorphic systems to transport mass in the downstream direction. Lowratios indicate the influence of the downstream geomorphic systems in maximizing massmovement in the upstream geomorphic systems. The presence of high and low ratiossuggests the presence of a high system-wide connectivity. As the ratio approaches unity,mass movement is minimized in the landscape indicating low system-wide connectivity.Applying the above approach to Estufa Canyon, Texas, illustrated that Estufa Canyon isa dynamic fluvial system with high system-wide connectivity.