Numerical modeling changes induced by the low lying areas adjacent to Ria de Aveiro

Abstract

The Ria de Aveiro lagoon is one of the largest shallow water estuarine systems in Portugal. It is characterized by a large number of narrow channels and intertidal areas. Despite several previous hydrodynamic studies about this system, their surrounding low lying lands were never included in the numerical bathymetries developed. The objective of this work is to evaluate if the inclusion of the low lying coastal adjacent flooded areas in the models’ numerical bathymetry induce changes in model predicted hydrodynamics for the Ria de Aveiro. The baroclinic finite volume numerical model, Mohid, was implemented to the Ria de Aveiro in a 2D mode. Two numerical bathymetries were developed, with and without th e low lying adjacent lands. The model calibration was performed through the bottom roughness tuning in order to compare the predicted and observed SSE time series for several stations into the lagoon. The validation tests show that the model can accurately reproduce an independent observed data set. To evaluate the hydrodynamic changes the model predictions for both bathymetries were analyzed and compar ed. It was performed harmonic analys is to sea level height and current velocity predictions. In addition, ellipse parameters were calculated to the M 2 and S 2 harmonic constituents at several stations along the lagoon. The results show that the mean velocity intensity is slightly higher (<0.1 ms -1 ) when including the low lying lands and that differences found for the Ria de Aveiro general circulation are almost negligible. However, some consistent patterns we re found that suggest the inclusion of these areas for more accurate studies for particular investigations within the lagoon.