A Survey on Precision of Nested Water Level Data Derived From Delft3D Model

One of the troublesome aspects of numerical modeling is to determine open boundaries for a model and to make sure that the boundary conditions employed at the open boundaries are compatible with physical processes being simulated within the interior of the model domain. In this investigation the accuracy of the water level data derived from delft3D employing nesting procedure were studied. These water level data were prepared to apply at open boundaries of a tidal channel model. This method was employed due to the lack of measuring stations in the proper geographical positions at the site. There was however three gauges inside the area, in which their records were used for the calibration of the model. Primary water level data derived from the model were compared with those derived from the in situ gauge. Observing dissimilarity between these two time series was the reason to search for the possible reasons. The importance of wind and/or bathymetry on the water level results also was studied. It was found that unreliable results were the outcome of using unjustified data at the boundaries. It is therefore, suggested that the boundary conditions to be verified and if necessary to be justified before applying at open boundaries. Several reasons, explaining the necessity of the justification, are presented.