Comparison of topo DEM and ALOS DSM in terms of 1D flood modeling: A case study from Alara River (Antalya-Turkey)

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Digital Elevation Models (DEM) and digital surface models (DSM) data are widely used in natural disasters, and they have an important to understand flood dynamics at present. Also, these DEM and DSM data have great importance in hazard and risk management studies and they are widely used for understanding the hydrodynamic of the floods. In this study, Alos DSM 30m and Topo DEM 10m data were evaluated within the scope of one dimensional (1D) flood modeling in the Alara River catchment. Extent, depth and velocity characteristics of floods are discussed over the DEM and DSM data obtained before and after the flood reclamation period, respectively. Maximum flow amounts are tested based on different return periods such as 10-50-100-1000 yrs via the hydraulic model created by Topo DEM and Alos DSM models. As a result, the flood extent in the study area did not change many indifferent return periods. DEM and DSM data have different results in terms of inundation-depth and velocity characteristics. Also, models show that the embankments have prevented the spread of water to the environment. It is seen that the water spreading over wide areas in Topo DEM data, does not spread much around the Alos DSM data except for certain points. Due to Topo DEM data was produced before the flood rehabilitation period and did not represent the present topography, it led to the existence of differences in flood modeling, especially in the spread areas. While the maximum spreading area is 3.60 km^2 in Topo DEM, it is 3.24 km^2 in Alos DSM. Both models carry similar results of the flood spreading area except for a few points show that in non-updated topography the surface Alos DSM 30m data can be used in flood studies.

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1D Flood modeling , Topo DEM , Alos , DSM , Alara river catchment

Aegean Geographical Journal

177

Aegean Geographical Journal