Analysis of the possibility of\ud using the distributed two-dimensional model Flo-2D for hydrological modelling

Abstract

The paper presents a hydrological model of the Glinščica watershed with the program \ud Flo-2D. The aim of \ud the research was to analyze the applicability of the two-dimensional mathematical model Flo-2D for \ud hydrological modeling and to compare the results with the one-dimensional HEC-HMS model. Flo-2D is \ud a commercial, physically based model with distributed parameters. lts main purpose is \ud modeling river hydraulics. lt continuously computes the rainfall runoff from the watershed according to the \ud topography or a\ud digital elevation model (DEM), the quantity and intensity of precipitation, the land use and soil \ud type. On the other hand, HEC-HMS is freely available software that enables to create a simple and \ud sufficiently detailed hydrologic model on the basis of precipitation, discharge and some watershed \ud characteristics. ln both cases precipitation losses were computed with SCS (Soil Conservation \ud Service) Curve Number loss method. Flo-\ud 2D model was calibrated by varying input and modeling parameters including grid size, roughness \ud coefficients and SCS Curve Numbers. The results of 10-year and 100-year events and 2, 12 and \ud 24-hour storms are also compared. The results of runoff volumes are comparable, but the shape of \ud runoff hydrograph computed with HEC-HMS model is much better. ln the Flo-2D model assessing the \ud Manning roughness coefficient and selecting the size of the grid cells are the most problematic, \ud whereas in the HEC-HMS model it is the assessment of the time of concentration. Calibration of the \ud model with distributed parameters is difficult and time-consuming. The results have shown that the \ud Flo-2D model can be used in hydrological\ud practice only in cases where good input data are available for the model and its calibration.\u