Incorporation of slope and rainfall variability in channel network extraction from DEM data at basin scale

This work presents an analytical framework that includes slope and rainfall variability with value of the critical area in defining a threshold for channel initiation processes for the whole river basin. The study overcomes the existing limitation of application of constant threshold for extracting channels throughout the basin by proposing slope and rainfall dependent variable threshold. The proposed algorithm successfully captures the spatial variability in drainage patterns at basin-scale characterized by different topographic characteristics. As basin-scale studies are mostly carried out using coarse-resolution digital elevation model (DEM), this methodology has been developed using Shuttle Radar Topography Mission (SRTM) data of 30 m spatial resolution. The resultant drainage pattern was compared with the published map based on field observations, which shows a closer match with field conditions. A front-end application was developed to implement the methods as an end-to-end process to make user interaction simpler.