Calibration and Validation of HEC-HMS Model for Chalakudy River Basin

Prediction of flood prone areas in a basin and evolution of the impact of climate change on water resources needs a correct estimation of the availability of water which will solely be achieved by hydrological modelling of the basin. However, modelling the hydrology of a basin is a complex task and models should be well calibrated to increase user confidence in its predictive ability which in turn makes the application of the model effective. In this study rainfall-runoff simulation model viz., Hydrologic Modelling System, developed by the Hydrologic Engineering Centre USA (HEC-HMS) has been calibrated and validated for Chalakduy river basin in Kerala, in Sothern India for prediction of its hydrologic response. The result shows Curve Number (CN), Lag time and initial abstraction (Ia) to be the sensitive parameters for the simulated stream flow. The statistical analysis of Nash-Sutcliffe model efficiency criteria, the percentage error in peak, percentage error in volume, and net difference of observed and simulated time to peak, which were used for performance evaluation, have been found to range from (0.70 to 0.87), (4.39 to 19.47%), (1.9 to 19%) and (0 to 1day) respectively, indicating a very good performance of the model for simulation of stream flow.