Influence of the Barrie de la Maza dock on the circulation pattern of the Ría of A Coruña (NW-Spain)

Abstract

[EN] A 3D hydrodynamical model is applied to the ria of A Coruña to analyze the evolution of the circulation pattern in the ria after the building of a breakwater (Barrie de la Maza dock) in the sixties. This circulation pattern has changed greatly. On the one hand, the circulation, which was almost parallel to the shore line under the original conditions, now shows a gyre near the end of the dock. On the other hand, a considerable increase (about 30%) in the velocities near the end of the breakwater and in the main channel of the estuary has been observed after the building of the dock. A stronger bottom shear stress has been generated in the estuary areas where the velocity increased. The bottom shear stress increase was particularly great (over 100%) near the end of the dock. This increase in the shear stress produced bottom erosion and matter resuspension, and consequently major changes in the bathymetry. In addition, in situ sedimentary measurements carried out by Lopez-Jamar (1996) corroborate the bottom erosion in the main chanel of the estuary and at the end of the dock produced by the velocity increase generated by the building of the breakwater.

[ES] Se ha aplicado un modelo hidrodinámico 3D a la Ría de A Coruña para el estudio de los cambios en el patrón de circulación de la ría tras la construcción del dique de Barrie de la Maza en los años sesenta. La circulación, la cual era casi paralela a la línea de costa bajo las condiciones originales, muestra en la actualidad un giro en las proximidades del extremo del dique. Además, puede observarse un considerable aumento (cercano al 30%) en las velocidades medidas en el canal principal cerca del extremo del dique, con el consiguiente aumento en el arrastre cerca del fondo. Este arrastre es especialmente importante cerca del extremo del dique, donde se observa un aumento próximo al 100%. Este aumento en el arrastre es responsable de importantes cambios en la batimetría de la zona. Medidas de campo realizadas por Lopez-Jamar (1996) corroboran la existencia de erosión en el canal principal del estuario cerca del extremo del dique