Rainfall runoff modeling using conceptual NAM model

Abstract

This paper describes the application of NAM (Nedbor Afstromnings Model), to investigate its performance, efficiency and suitability in Bina river basin of Madhya Pradesh. NAM is a deterministic, lumped and conceptual rainfall-runoff model. The model was developed, calibrated and validated using flow data at Rahatgarh site on Bina river. The model was found suitable for Bina basin in simulating hydrological response of the basin to the rainfall and predicting daily runoff with high degree of accuracy. The coefficient of determinations for the model calibration and validation were 0.796 and 0.609 respectively indicating good agreement between the observed and simulated runoff in terms of timing, rate and volume and shape of hydrograph. The model was evaluated based on Nash–Sutcliffe Efficiency Index (EI) and Sum of Square of Error (SSE). The model was found efficient with Efficiency Index 81% and found capable of predicting runoff for extended time period in Bina basin. The sensitivity analysis of the model was carried out to identify the most sensitive model parameters. Effects of the model parameters on simulated peak and low flows were analysed. Coefficient of Overland flow (CQOF) was the only model parameter showing significant effects on peak and low flows both.