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Duran C.,Confederacion Hidrografica Del Ebro | Lanao M.,Tragsatec. Residencial Paraiso | Perez L.P.Y.,CSIC - Centro de Investigacion y Tecnologia Agroalimentaria | Chica C.,Consultor | And 2 more authors.
Limnetica | Year: 2012

This study presents the monetary costs that the zebra mussel invasion has involved in the Ebro basin since 2005 to 2009 for the sectors which use water in their activities. The economic impact associated with this invasion is derived from the operation problems in affected facilities and the costs added due to the cleaning and control treatments. The work methodology is based on the analysis of the survey address to energetic, industrial, agricultural, recreational, public administrations and supplies sensitive to be affected by the zebra mussel invasion. In total, 1329 surveys were sent by post and email to different agents of several sectors. The response rate was 28.4%, allowing a detection of 103 affected users in the basin. The results indicate that costs associated to the zebra mussel expansion in the Ebro basin have not stopped to increase in the last years, reaching 11.6 millions of Euros in the period of study. The most implicated sectors are public administrations, with a 55.1% of the total costs followed by energetic companies, with a 26.4%. Geographically, it is in the High Ebro where more money has been invested in the fight against this alien species during the five years of study. © Asociación Ibérica de Limnología, Madrid.

Angulo R.P.,University of Zaragoza | Ormad M.P.,University of Zaragoza | Ovelleiro J.L.,University of Zaragoza | Navarro P.,Confederacion Hidrografica Del Ebro
Tecnologia del Agua | Year: 2012

The Ebro Basin Water Authority has developed a methodology that allows to evaluate quantitatively the risk of failing to achieve the environmental objectives set on the Water Framework Directive on surface water bodies. For that purpose, a numeric value for the global pressure has been developed for the different types of pressures existing. It was also necessary to set numeric values for the impact based on ecologic status, chemical status as well as compliance with the requirements of protected areas. The results have allowed to classify the water bodies according to the higher risk in order to prioritize the actions to be taken. Once the results obtained have been analysed, it can be concluded that the developed methodology for the risk evaluation meets perfectly the expectations.

Mariscal De Gante Lopez A.,Confederacion Hidrografica Del Ebro
Dam Maintenance and Rehabilitation II - Proceedings of the 2nd International Congress on Dam Maintenance and Rehabilitation | Year: 2011

Alloz dam, its reservoir and foot reservoir are located in the Foral Community of Navarra. Inagurated in 1930, it regulates the headwaters of the river Salado, providing resources for irrigation in the area and for the production of electricity. It is one of the first double-curved arch dams built in Spain. Due both to the need for adaptation of its elements to the new standards as well as to solve several problems arising from their exploitation, it has been necessary to undertake several remedial measures which are described in this paper (operation of bottom drains, fitting of the restitution channel and recovery of the river reach downstream from the foot reservoir and repair of irrigation intake after the avenue of 2007). © 2011 Taylor & Francis Group, London.

Gutierrez F.,University of Zaragoza | Mozafari M.,Shiraz University | Carbonel D.,University of Zaragoza | Gomez R.,Confederacion Hidrografica Del Ebro | Raeisi E.,Shiraz University
Engineering Geology | Year: 2015

La Loteta Reservoir, with a storage capacity of 105hm3, is located in a large karst depression around 6km long on the southern margin of the Ebro River valley, NE Spain. Geomorphological mapping and borehole data indicate that the development of the basin is related to subsidence due to interstratal dissolution of the underlying halite- and glauberite-bearing evaporites. The dam site corresponds to the water gap carved by the small drainage that captured the formerly internally drained depression. Here, the foundation and abutments of the dam include a horizontal and laterally extensive gypsum unit 11m thick. This sedimentary package showed considerable evidence of karstification in the excavation carried out during the construction of the dam, especially in the left abutment, where it was largely removed. The watertightness system of the ca. 1.5km long earth dam includes a vertical clay core, a horizontal clay blanket, a cut-off wall, and grout curtains 675m and 255m long on the left and right abutments, respectively. Multiple data including leakage discharge measured in the different zones of the drainage system, seepage points mapped downstream of the dam, borehole and piezometric data, and an equipotential map, reveal that leakage essentially occurs through the gypsum unit. The main leakage occurs beneath and next to the left edge of the dam body. This water loss and the associated enlargement of karst conduits are also supported by settlement measured on the dam crest and the occurrence of sinkholes within the reservoir, next to the left abutment. Additional seepage across the grout curtain in both abutments is also identified. Although unlikely, there is also the potential for the water to escape towards an adjacent watershed, where the base level is located below the maximum water level of the reservoir. An additional cut-off wall has been projected to block the main leakage path. © 2014 Elsevier B.V.

Ibanez C.,IRTA Aquatic Ecosystems | Alcaraz C.,IRTA Aquatic Ecosystems | Caiola N.,IRTA Aquatic Ecosystems | Rovira A.,IRTA Aquatic Ecosystems | And 6 more authors.
Science of the Total Environment | Year: 2012

The lower Ebro River (Catalonia, Spain) has recently undergone a regime shift from a phytoplankton-dominated to a macrophyte-dominated system. This shift is well known in shallow lakes but apparently it has never been documented in rivers. Two initial hypotheses to explain the collapse of the phytoplankton were considered: a) the diminution of nutrients (bottom-up); b) the filtering effect due to the colonization of the zebra mussel (top-down). Data on water quality, hydrology and biological communities (phytoplankton, macrophytes and zebra mussel) was obtained both from existing data sets and new surveys. Results clearly indicate that the decrease in phosphorus is the main cause of a dramatic decrease in chlorophyll and large increase in water transparency, triggering the subsequent colonization of macrophytes in the river bed. A Generalized Linear Model analysis showed that the decrease in dissolved phosphorus had a relative importance 14 times higher than the increase in zebra mussel density to explain the variation of total chlorophyll. We suggest that the described changes in the lower Ebro River can be considered a novel ecosystem shift. This shift is triggering remarkable changes in the biological communities beyond the decrease of phytoplankton and the proliferation of macrophytes, such as massive colonization of Simulidae (black fly) and other changes in the benthic invertebrate communities that are currently investigated. © 2011 Elsevier B.V.

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