Modeling renewal times in Amvrakikos Gulf, Greece

Abstract

The Amvrakikos Gulf, located in the northwest Greece, is one of the largest semi-enclosed embayments being about 40 km long and 15 km wide. Water renewal is made via a narrow channel which connects the Gulf with the Ionian Sea having a 3.0 km length, width ranging from 0.8 to 2.0 km and depth from 2.0 to 13.0 m. The most common terms being used to indicate how fast the water of semi-enclosed coastal embayments is renewed are hydraulic retention time (HRT) and residence time (RT). A preliminary estimation of HRT and RT is performed via a 3-D integrated model consisting of the hydrodynamic sub-model FLOW-3DL and the water quality sub-model QUAL-3DL. The models involve the 3-D non-steady state continuity, momentum and convection-diffusion equations expressed in layer formulation. A space-staggered computational grid was used and the following conclusions were drawn: (1) The HRT ranges from 1.86 to 2.42 years. (2) The flow rates of Louros and Arachthos rivers, which gush into the Gulf, reduce the HRT by 0.56 years. (3) The effect of the wind on HRT is minor due to the small size of the entrance to the Gulf. (4) The theoretical RT is equal to 3.85 years. © 2012 Global NEST Printed in Greece. All rights reserved.