Vol. 2, Issue 6, Part L (2016)

Abstract
Geographical Information System (GIS) support based Geomorphological characteristics of Swarnamukhi river watershed located in Nellore district of Andhra Pradesh have been used to generate Geomorphologic Instantaneous Unit Hydrograph (GIUH). GIUH can be used as a transfer function for modelling the transformation of excess rainfall into surface runoff, in which excess rainfall is an excitation to the hydrologic system. The drainage network and slope map can be extracted from the Arc GIS software. The computation of Horton’s ratios and their application in generating the Geomorphological Instantaneous Unit Hydrograph (GIUH) can provide a solution for ungauged watershed. The aim of this paper was to estimate the peak discharge of the swarnamukhi river basin located at Nellore district. Peak discharge is estimated on an event based approach during the period of 2009 - 2013, total ' 10 ' events are considered. The maximum and minimum elevation of the basin is 312 m and 29 m above MSL, respectively. Swarnamukhi River is the 5th order watershed comprised of about 957.92 km2 area. The slope of the watershed has maximum area covered nearly level (0-1)% and very gently sloping (1-3)%. Length of maximum order stream is 46.92 km, whereas Stream length ratio (Rl) is 2.29. The obtained results were compared with recorded peak discharge in hydro observation site of watershed. The models of Relative Mean Error (RME), Nash- sutlciff Error (NSE) and Root of Mean Square Error (RMSE) in watershed were compared with each other.