Water Quality in the Future Alcolea Reservoir (Odiel River, SW Spain): A Clear Example of the Inappropriate Management of Water Resources in Spain

Abstract

The Odiel River is located in southwestern Spain; the greater portion of its basin is composed of materials from the Iberian Pyrite Belt (IBP), an area with numerous massive sulfide deposits that have been highly exploited since the third millennium BC. As sulfides come into contact with the atmosphere due to mining activity, oxidation occurs, generating a highly toxic acidic leachate with large concentrations of sulfates and metals, a process which is known as acid mine drainage (AMD). As a result, the Odiel River and most of its tributaries are severely contaminated. The construction of two large dams in the Odiel River basin is planned. The most advanced project is that of the Alcolea reservoir, with a storage capacity of 274 hm 3 , whose construction has already begun, with a total budget of around e164 million. There are reasonable doubts about the final quality of the reservoir water, as this dam will regulate a river with a mean pH close to 3.5 and large concentrations of toxic elements. This paper analyzes the data of water quality in the Alcolea reservoir. The results show that the reservoir water will be acidic and not useful at all, although more specific studies are necessary to obtain the exact estimation of its hydrochemical characteristics. It seems unwise to start building the dam, which requires a large economic investment and will have a vast environmental impact, without first conducting these studies. This proves that water management in Spain is still based on political motivation rather than on technical criteria and good management of natural and economic resources.

Application of Ecopath model on trophic interactions and energy flows of impounded Manwan reservoir ecosystem in Lancang River, southwest China

“…Approximately 70% of river systems are regulated by large reservoirs around the world and 20% of the water flows are altered (Hooper et al 2001). The main aims of dam construction are hydroelectricity generation, water supply, flood control, aquaculture, and agricultural irrigation (Weliange et al 2006;Ol ıas et al 2011). Because of their high productivity, reservoir ecosystems are considered an important habitat for numerous aquatic organisms.…”

Hydrological modeling of a watershed affected by acid mine drainage (Odiel River, SW Spain). Assessment of the pollutant contributing areas

“…1), aimed at storing tailings produced by hydrometallurgical mineral processing from Riotinto. The construction of a new reservoir (Alcolea, 246 hm 3 ) has recently commenced, which will be the largest of the watershed and may store acidic waters if remediation measures are not put into practice to reduce the AMD load (Olías et al, 2011).…”

“…(Table 5), which represents between 18 and 32% of the pollutant load carried by the Odiel River at Gibraleón. Just at the confluence (Olías et al, 2011). The Meca River (point 88), the last tributary of the Odiel before the confluence with the estuary, carries a high pollutant load into the Sancho Reservoir, standing at 420 t/yr of Al and 150 t/yr of Zn (Table 5).…”

A geochemical approach to the restoration plans for the Odiel River basin (SW Spain), a watershed deeply polluted by acid mine drainage

“…The Alcolea reservoir (247 hm 3 ), with a final budget of almost €164 million, is the most advanced project, and its construction has already begun. Nevertheless, the water of the reservoir will be acidic if remediation measures are not put into practice (Olias et al 2011).…”