Rehabilitation of the Tagus Estuary

Abstract

The source of the River Tagus is in the Albarracin mountains in Eastern Spain and runs for over 1000 km to form the largest western Europe estuary, with approximately 325 square km of surface. The estuary, also called “mar da palha” (sea of straw), is characterised by very high levels of water retention. It includes a shallow inner delta and an inter-tidal zone comprising more than 40% of the total surface area. With an average depth of 10.6 metres (the maximum depth is 40 metres) and a water flow rate that can exceed 2.3 metres/second (at low tide in the deep channel running along the south bank), the receiving body of water through strong tidal action is quite considerable (Figure 1).