Geoinformatics-Based Morphologic Analysis of the Ramis River, an Endorheic Andean River

Abstract

One way to quantify the various morphometric features of a river is through morphology. The North–south-flowing Ramis River is a major tributary of Lake Titicaca, one of the world’s largest lakes. The Ramis has been exhibiting marked changes in its morphology, loss of cultivation areas, and limitations in the operational performance of its associated public infrastructure. Thus, this study aims to present the fluvial classification of the Ramis River. To this end, the basin was examined to establish the various morphometric parameters along thirteen representative sections, which do not include the river delta, through the analysis of the planimetry, sediment properties, river dynamics, cross sections, longitudinal profiles, and hydraulic behavior. Our results indicate that the upper Ramis exhibits a rocky-alluvial valley bed relatively straight and becomes more sinuous downstream. The study stretch is classified as types E5, D4c, C4b, C4, C4c, B4c, and B4cm according to the Rosgen stream classification scheme. Positive correlations were found between stream cross-sectional flow area, bank width, and discharge concerning the size of the watershed. The Ramis River exhibits morphologic units associated with debris flows and channel processes (e.g., point bars, and mid-channel deposits). The southern Ramis exhibits lower efficiency due to a decline in slope and competition, the northern Ramis contains more energy for the conveyance of bed load. According to the Ramis’ stability report, segments 11 to 13 of the stream are deteriorating, the intermediate portions indicate a relationship related to a braided river, and the lower reaches undergo a process of aggradation.