Imelida G. Torrefranca, R.E.S. Otadoy, A.F. Tongco
The study presented a method of characterizing landform dynamics that integrates a divide stability metric and hypsometric analysis. Chi (χ) - a proxy for steady-state river channel elevation - indicated a drainage divide stability. Simultaneously, the hypsometric analysis provided information on a basin's geologic development stage and erosion proneness. The study used a 30 m SRTM digital elevation data, the DivideTool/TopoToolbox of MATLAB, and the SWAT model. The tool computed χ values following the stream network, enabled the selection of divide sections, extracted channel head's χ values, determined divide stability by predicting migration direction for unstable divides, and produced histograms of χ values for each divide section. Equal χ values at the channel heads of opposing river networks indicated a stable divide. In contrast, a difference in χ values suggested an unstable divide and a potential to migrate from low χ values towards the divide's high χ values side. The study proposed the mean χ difference (χmd) metric to indicate the degree of divide mobility. Meanwhile, the SWAT model defined the basins and subbasins and set the hypsometric analysis parameters. Each subbasin's hypsometric integral (HI) was used to create a continuous surface of HI values. The combination of χmd and HI analysis revealed nine subbasins with highly mobile divides and high erosional areas, identifying them as high-priority conservation zones. River basin characterization can utilize the new approach to target areas for location-specific land and water conservation measures and other developmental goals. © 2022 International Association for Hydro-Environment Engineering and Research.
Graduate School of Engineering, University of San Carlos, Cebu City, Philippines; Department of Agricultural and Biosystems Engineering, Bohol Island State University, Bohol, Philippines; Theoretical, Computational Sciences and Engineering Group, Department of Physics, University of San Carlos, Cebu City, Philippines; Center for Geomatics and Environmental Solutions, University of San Carlos, Cebu City, Philippines
