Sobre la calidad del agua del futuro embalse de Alcolea (Cuenca del río Odiel, Huelva)

Abstract

The Odiel River drains the central part of the Iberian Pyrite Belt, an area with many polymetallic massive sulphide mines that have been worked since prehistoric times. As a consequence of the oxidative dissolution of the sulphides exposed in the surface associated to mining activities, acid mine drainage pollution is an important processes in the Odiel basin that lower considerably the water quality of the river. In fact, near its mouth, the Odiel river has a very low pH and high concentrations of metals and metalloids in solution. Two reservoirs are planned in the Odiel river within the National Hydrologic Plan: Alcolea and Coronada. The construction of the Alcolea dam is suppose to start this year, with a total planned investment of 200.000.000 . After the study and analysis of the water quality in the watershed of the Alcolea dam, and the study of the chemical evolution with time in others water dams in the Odiel basin, the inferred longterm quality for the water in the Alcolea dam will not allow its direct use for agriculture or industrial uses. Therefore, taking into account the important investment planned and the poor quality of the water expected, it is necessary an important re-evaluation of the original project that takes into account, in a more rigorous way, the final quality of the water accumulated in the dam