Introducción al análisis de los riesgos de inundación en las riberas de las áreas estuarinas: El caso de las poblaciones adyacentes a la Ría de Huelva (SO España)

Floods are natural events that occur in depressed areas. These phenomena can be related with extreme river discharges in fluvial valleys or with wave surges in coastal areas. In estuarine areas, both causes can coincide during stormy periods. The Ría de Huelva is the common estuary of Tinto and Odiel rivers, which are extremely irregular because of their pluvial character. The slatey-quartzitic character of the drainage area induces an immediate response of the fluvial flow to the rains. This estuary is submitted to a mesotidal regime, with a mean tidal range of 2.0 metres, but with extreme equinox high waters that can reach 1.7 metres over the mean tide level (74 cm. over the mean high waters). Meteorologic surges caused by low pressures and winds blowing from the south to the coast can increment the water level near to 1 m. over the tidal level. Strong rains and meteorologic surges occur at same time during Atlantic storms. When these storm coincide with equinox high tides the towns located at the margins of the estuary are normally flooded