Rainfall-runoff Modelling Based on GIUH Approach in a GIS Environment

摘要

Geomorphological Instantaneous Unit Hydrograph (GIUH) is a physically based rainfall-runoff modelling approach, appropriate for ungauged catchments. Here, the characteristics of the instantaneous unit hydrograph (IUH) are related to the geomorphological characteristecs of the basin. A mathen atical model, which enables the evaluation of parameters of the Clark model for derivation of the IUH using geomorphological characteristics was applied to a small catchment, Barchi, which lies in the North Karnatra district, Karnataka. Observed hourly rainfall-runoff records were used to check the applicability of this method. The geomorphological parameters and time-area diagram form important input for the GIUH based Clark model and these parameters for the catchment -were generated using a GIS software Integrated Land and Water Information system (IL WIS). From the hourly rainfall-runoff records, eight events were extracted for the analysis. The GIUH based Clark model simulated these events quantitatively as well as qualitatively. Further, the me of GIS has provided a great automation and efficiency in the estimation of the geomorphological parameters required for the model application.