Estuaries of the Huelva Coast: Odiel and Tinto Estuaries (SW Spain)

The estuary of the Odiel and Tinto rivers is located in the southwest of the Iberian Peninsula on the western Gulf of Cadiz (Atlantic Ocean). The Huelva estuary is constituted by the common mouth of the Odiel and Tinto Rivers in a “Y” shape oriented in a N-S direction across 35 km long incised valley. This estuary was generated after the Flandrian Transgression (Holocene), which signified the marine inundation of the main fluvial valleys incised by the rivers during the last Pleistocene lowstand. It extends along the south-western coastal margin of the Guadalquivir sedimentary basin that was incised on Cenozoic non-consolidated sediments during the late Pleistocene and early Holocene when sea level was located up to 100 m below the present position. This estuary is presently completely filled with sediments and has started to prograde to build a delta. The fluvial basin of both rivers is seriously affected by acid mine drainage, so this estuary have a induces important changes in the chemical characteristics of the water, suspended particulate matter (SPM) and sediments.