Monitoring a river channel network at Salar de Uyuni using Landsat ETM+ images

摘要

Monitoring and mapping of alluvial surfaces and distal fluvial system has an important role for studying the depositional basin and river behaviour at its terminus. Experiences show rivers in semi-arid areas get smaller through their terminus and create a complex pattern at downstream parts. Remote sensing images can be used to monitor distal fluvial system and reveal changes of channels activity. In this study, we examine the feasibility of mapping and identifying the changes over time of a semi-arid area by Landsat ETM+ images. The study area is at the terminus of a fluvial system in Bolivia. Change detection techniques were applied to emerge the temporal and spatial changes. We used precipitation data of the area for better interpreting the images in different dates. The ETM+ image analysis results show changes in river morphology. It was also observed by the visible bands that the reflectance of abandoned channels increased after several consecutive weeks of high precipitation. The changes in dry seasons are more observable by the infrared bands. The study shows that Landsat ETM+ images in combination with field work data have a good potential to identify temporal and spatial changes at river morphology in a qualitative manner.