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Impact evaluation of the Vila Viçosa small hydroelectric power plant (Portugal) on the water quality and on the dynamics of the benthic macroinvertebrate communities of the Ardena river

2004; Volume: 23; Linguagem: Inglês

2660-8537

Teresa Maria Gonçalves Moreira de Jesus, Nuno Formigo, P. Santos, Géssica Tavares,

Aquatic Invertebrate Ecology and Behavior

Over a two-year period a study of the Vila Vicosa small hydroelectric development, located on the Ardena river (hydrographical basin of the Douro river, Portugal), was conducted, with the objective of evaluating the impact of its operation on the water quality and on the dynamics of the benthic macroinvertebrate community. A morphological, hydrologic and physico-chemical characterization of the system was done, an analysis of the benthic macroinvertebrate communities looking into their structure and dynamics, as well as ecological and physiological characteristics. With the physical and chemical data, a study of its spatial and temporal variation was performed. With the data related to the macroinvertebrate communities, an analysis of the spatial variation of some indexes and metrics and of the (non) similarity between the samples collected were done, bearing in mind the composition of the communities, through different techniques of multivariate analysis. After the analysis of the data, it is possible to say that the Ardena River is a lothic system, with good water quality, in which the working of the small hydroelectric power plant causes alterations on the macroinvertebrate community, due to the alteration of the natural hydrologic regime. The impact on the macroinvertebrate communities is lower upstream of the plant, where the flow is minimal throughout the whole year leading to a change in the structure of the community. Downstream of the plant, where the flow is extremely variable, there is an impoverishment of the communities, leading to the displacement of substrate and organisms.