Evaluation of Conceptual Hydrological Model (HBV) Parameters for Predicting Shahid Rajaei Dam Basin Flow by Monte Carlo Method

Water management in water basins requires information of some facts and full acquaintance of basin conditions, which is problematic due to the deficiency of data collection stations in the country. One of the most suitable methods for flow simulation is the use of hydrological models. In this study, in order to simulate runoff caused by precipitation and to investigate the apparatus of runoff formation and outflow at the outlet of Shahid Rajaei Dam basin located in Sari, the HBV-Light model was used. The purpose of evaluating the stochastic method is to estimate the model parameters and reduce the uncertainty. The length of the daily statistical period was the variables of temperature, precipitation, runoff and evaporation from 1981 to 2015. The Monte Carlo random method was used to estimate the appropriate parameters for the study area. For a consistent assortment, the values of the parameters with a relatively good coefficient of determination were used in the validation section. Finally, the results show the good aptitude of the model in simulating runoff in the study basin. The values of coefficient of determination 0.87, Nash coefficient (NS) equal to 0.66 in the range of good evaluation and RMSE equal to 0.26 in the validation period indicate this issue. In the analysis of uncertainty caused by model parameters, K1, K2 and UZL parameters were identified as the most sensitive in the model reaction subroutine. Therefore, the results showed the importance of accurate determination of water and soil parameters affecting subsurface runoff.