Flow Routing and Surface Water Balance Simulation of a Tank Cascaded Catchment Using Coupled MIKE SHE/MIKE 11 Modeling

摘要

Hydrology of a tank cascaded basin in semiarid region is unique and different from a plain terrain hydrology as it consists of intervening surface storage structures called tanks. The incorporation of physical processes of irrigation tank cascaded system in hydrological modeling is essential for accurate estimation and simulation of its water balance components. The earlier studies of rainfall-runoff modeling in such catchments and the effects and processes of these tanks were lumped while modeling as it requires extensive data. Routing through the streams without considering the intervening tank storages will not give accurate estimation of surface water resource potential. Hence, an attempt has been made in this study to characterize the physical processes and to simulate the flow routing through an irrigation tank cascaded system with the application of coupled MIKE SHE and MIKE 11, a fully integrated physically based deterministic and distributed model. With the help of primary and secondary data, the model has been set up by coupling MIKE SHE and MIKE 11 model and the dynamics of water movement has been simulated. The model simulation results have been evaluated through calibration and validation of simulated tank yield with that of observed values. Water level at three tank outlets located at the upper, middle and tail reach of the tank cascaded catchment was used to study the model performance evaluation. The Nash-Sutcliffe coefficients obtained are 0.91, 0.94 and 0.92 for three tank water levels showing satisfactory goodness of fit between the observed and simulated water levels. The statistical parameters obtained from the validation process, such as error matrix, correlation coefficient and Nash-Sutcliffe coefficient values, indicate good simulation and prediction capability of the developed coupled model that incorporates a methodology which takes into account all the physical processes of the tank cascaded system.