Long-term hydrologic simulation using storage and source area concepts

A daily rainfall–runoff model of the lumped, storage- and source area-based concepts incorporating in runoff generation the processes of initial abstraction, evaporation transpiration, infiltration, drainage, percolation, deep seepage, source area runoff, throughflow and base flow, is proposed. It is calibrated and validated for data of five catchments falling in different climatic regions of India. The model is found to perform well on all the watersheds except one, exhibiting minimum runoff coefficient. It performs better on the high runoff producing watersheds than on the low ones. In addition, the dormancy/dominancy of various processes in various watersheds is identified, and the expansion/contraction of the source area explained. The deep percolation is found to affect significantly the runoff generation in all the considered watersheds. Since the models of Moore et al. (1983) and Putty and Prasad (1993) do not account for this process, the proposed model forms advancement over these models.