MODELLING OF A RIVER SYSTEM USING MIKE-11

Abstract

An integrated MIKE 11 NAM and HD model has been developed to simulate the rainfall-runoff process in the Ram Munshi Bagh Sub-basin of Jhelum Basin. The model was calibrated using daily rainfall, evaporation, temperature and discharge data of the period 1985 to 2005. The model was then validated by calculating the daily discharge values for next 10 years. The coefficients of determination for the model calibration and validation were 0.749 and 0.792 respectively, indicating good agreement between the observed and simulated runoff. The performance of the model was evaluated on the basis of Nash–Sutcliffe Efficiency Index (EI) and Index of Agreement (d). The EI and d values obtained were 0.75 and 0.93 respectively for calibration period while the values of EI and d for validation period were 0.79 and 0.94 respectively. Sensitivity analysis showed that Coefficient of Overland flow (CQOF) was the most sensitive parameter affecting model efficiency as well as peak and low flows significantly. The calibrated model was also used to simulate extreme flood events occurred in the study basin. History of Kashmir is full of the tragic accounts of floods, which mostly occur due to insufficient carrying capacity of its only drainage channel i.e. Jhelum. The simulated extreme flood events showed a difference of 3-17% in their peaks for different flood events. For the 2014 flood event the simulated discharge was 2055 m3/s which was only 3.2% more than the observed discharge indicating suitability of present model setup for simulating rainfall runoff process in the Jhelum basin including simulation of extreme flood events.