Morphological characterization using South Rivers Toolbox in the Duqueco river: A support tool for river management

The phenomena associated with global climate variability may lead to more intense extreme events, thus causing an increase in floods and prolonged droughts. In view of this situation, the Chilean Directorate of Hydraulic Works (DOH) has the task of selecting the works to be executed with the highest priority with the annual budget, to control and mitigate the effects of floods. Hence the need for a tool that includes the evaluation of fluvial morphodynamics, which allows the management of hydraulic works compatible with the processes of response and adjustment of the channels. The objective of this study is to characterize the fluvial styles of the Duqueco River based on its geomorphology, to understand the character and behavior of the fluvial corridor in a semi-automatic way applying GIS techniques and Python geoprocessing. The first stage of the River Styles framework is applied through the South Rivers Toolbox program, which characterizes and classifies fluvial styles based on hydromorphological attributes measured at segment scale, implementing a semi-automatic approach that reduces expert judgment. Previously, the disaggregation and aggregation framework is used, which determines channel attributes at a local scale, and then aggregates them with a statistical test in larger reaches. The whole process is performed in a semi-automated way with tools from the South Rivers Toolbox set within the QGIS software. As results, 36 main fluvial styles and 47 complementary styles are classified and characterized, and the river channel is analyzed in 3 zones. The upper zone is characterized by being mostly confined, mono-channel, with a bed of boulders and blocks, being highly intervened by power generation works; the middle zone is still mostly confined and mono-channel, with a change in the type of bed towards boulders. Finally, the lower zone is more diverse in styles, mostly unconfined, with a high presence of geomorphic units that give way to multichannel and transition zones.