Spatial variation in drainage characteristics and geomorphic instantaneous unit hydrograph (GIUH); implications for watershed management—A case study of the Varada River basin, Northern Karnataka

Geomorphological characteristics can be treated as signatures of hydrological responses. Geomorphologic instantaneous unit hydrograph (GIUH) is of utmost use in planning watershed management programs on a broad scale in absence of hydrologic data. Fifth order basins from different agroclimatic zones in the Varada River basin were selected to understand the spatial variation in drainage characteristics. These sub-basins show significant differences in their morphometric properties such as basin area, drainage density, bifurcation ratio, circularity ratio, constant of channel maintenance etc. These differences reflect variation in the hydrological process and geomorphologic instantaneous unit hydrograph (GIUH) of different sub-basins and can be used to understand watershed management aspects. Fifth order sub-basin in the Southern Transition agroclimatic zone is potential for artificial recharge programs. Sub-basins in the Hilly non-forest zone on the north are ideal for surface water storage like tank development program while Forested Hilly zone on the north are environmentally sensitive and prone to erosion.

Research Highlights
► Morphometric characteristics of the Sub-basins located in different agroclimatic zone within the Varada basin are studied.
► NASH parameters-scale (K) & shape (n) derived using the morphometric properties are used to asses the basins potential.
► These results are used to compare and prioritize the basins for watershed management and decision making.
► While Sub-basin in the Hilly (non-forest) zone on the north is ideal for surface water storage.
► Sub-basin in the Southern Transition agroclimatic zone is potential for ground water storage and artificial recharge.