Evaluation of automatic drainage extraction thresholds using ASTER GDEM and Cartosat-1 DEM: A case study from basaltic terrain of Central India

In the study, the digital elevation models from ASTER GDEM and Cartosat-1 of 30m resolution were used to evaluate the thresholds in automatic extraction of stream network at six thresholds of 0.05km2, 0.125km2, 0.25km2, 0.50km2, 1.0km2 and 2.0km2 in Neri watershed in basaltic terrain of Central India. At stream thresholds of 0.05km2, Cartosat-1 DEM shows higher channel initiation points (150) than ASTER (127). As we increase the stream thresholds from 0.05km2 to 2.0km2, the channel initiation points are consistently decreased in two input DEMs. The correlation coefficient R2 between the drainage area thresholds and stream length for ASTER and Cartosat-1 DEM shows 0.94 and 0.92, respectively. The comparative evaluation of morphometric indices shows that threshold of 0.05km2 is found to be optimum to obtain the finer drainage networks particularly from Cartosat-1 DEM, when compare to the ASTER GDEM of same resolution.