Satellite and UAV derived seasonal vegetative roughness estimation for flood analysis

Abstract

One of the purposes of river management is the disaster protection of the nearby population. The effect of riparian vegetation on hydraulic resistance and conveyance capacity makes it a vital parameter for this purpose. With remote sensing techniques, vegetation information can be estimated. This paper's objective is to combine UAV and satellite imagery to obtain vegetation parameters with moderate resolution for hydraulic modeling, and to assess the seasonal effect of the vegetation on the Manning coefficient. Typhoon Hagibis was simulated with a 2D hydraulic model with a dynamic vegetative roughness estimation routine. Results demonstrate that this method achieved less error than the traditional static roughness value method of hydraulic modeling. The seasonal effect of the vegetation on the roughness was shown by a relationship between the percentage of vegetation cover and the average Manning in the stretch.