Improved Cartosat-1 Based DEM for Flood Inundation Modeling in the Delta Region of Mahanadi River Basin, India

Abstract

An accurate flood mapping is a non-structural measure that helps to reduce damages and minimizes losses. The availability of large-scale and good quality topographic input data is of great concern for such studies. The present study involves the integration of Cartosat-1 stereo image pairs (remotely sensed) and ground truth points (surveyed) to develop digital elevation model (DEM) for the Mahanadi delta in India. The integration was performed for two cases: (i) A single Cartosat-1 image at a time and (ii) Aggregation of Cartosat-1 images one after another. Both the cases involve different numbers of ground control points (GCPs) (to be integrated with Cartosat-1 images) to study the quality and suitability of DEMs for flood inundation modeling. The best one among the DEMs prepared for each Cartosat-1 image with different number of GCPs was further used for hydrodynamic modeling. The MIKE 11 model was calibrated for 2009 and validated for 2010 using cross-sections extracted from Cartosat-1 DEMs. Further, bathymetry for the MIKE 21 model was prepared using the best Cartosat-1 DEM. MIKE FLOOD model setup was prepared to simulate flood inundation for the year 2011. The results indicate that DEMs of reasonable quality can be generated by incorporating GCPs and rational polynomial coefficients. The areal extent of simulated flood using MIKE FLOOD is in reasonable agreement with the observed counterpart.