PROPOSAL OF A METHOD TO FORM SURFACE FLOW DIRECTION DATASET BASED ON ACTUAL RIVER INFOMATION

Abstract

 Elevation and surface flow direction data are useful for the analysis of hydrologic processes in a catchment. Surface flow direction is generally determined by steepest downward slope based on depression-filled elevation data. However, since the steepest downward slope is affected by the elevation correction and errors in the input elevation data, resulted surface flow direction does not reflect the actual river geometry. Here, a method to form catchment dataset was developed based on actual river information to minimize elevation correction and improve reproducibility of river geometry. As a result, the reproducibility of river geometry was significantly improved and the elevation correction was reduced at multiple spatial resolutions from 30 m to 1000 m. In addition, the complex river geometry such as meandering and tributary confluence was reproduced while it was difficult to do in conventional approaches. This method contributes to catchment-scale flood control, wide-area river environment management, and disaster prevention measures using the digital twin.