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Universidade do Minho (2008)

Sistemas de indicadores para a caracterização da qualidade de águas superficiais : um caso de estudo

Casado, Ana Maria de Almeida

Titre : Sistemas de indicadores para a caracterização da qualidade de águas superficiais : um caso de estudo

A system of indicators for surface water quality assessment : a case of study

Auteur : Casado, Ana Maria de Almeida

Université de soutenance : Universidade do Minho

Grade : Mestrado em Engenharia Municipal 2008

Résumé
Water Framework Directive (WFD) started a new age in European water policy, extending the protection to all the natural waters. The goal is to obtain a good condition for water applying the principle of management based on river basins, establishing the need for introducing water prices for its sustainable use and a combined approach for pollution control. The water storage by dams allows reaching a more steady balance throughout the year, diminishing the dependence of the natural water regimen, as much in scarcity case, as of great excesses. An important and essential water reserve in Portugal is the reservoir of Alqueva, which receives domestic and industrial effluents and agricultural and forest runoff. The extreme affluence of nutrients, solid material and organic substances leads to the deterioration of water quality, causing accumulation of nutrients, in particular nitrogen and phosphorus, essential elements for eutrophication phenomena occurrence. The need for establishing a methodology to assess the quality of surface waters under eutrophication, leads to the construction an environmental indicator system. The great variety of environmental indicators described in literature advises to the focus and organization of the indicators around a current conceptual model and of easy understanding. Model DPSIR (Driving Forces - Pressures - State - Impact - Responses) reflects an analysis of the relations between the environmental system and the human system. This conceptual model was applied in the present work for the assessment of the water quality in the reservoir of Alqueva and its tributaries. The thematic studied were : bacterial contamination, oxygenation state, eutrophication, physical-chemical state and heavy metals. For each thematic the indicators of forces, pressure, state, impact and responses were defined, although only the thematic of state indicators was developed in a more detailed approach. The information on the water quality was obtained from the available data in the National Water Quality Monitoring System, in a four years series : 2001, 2002, 2003 and 2004. The state indicators were determined both mensal and annually.

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Page publiée le 28 mars 2011, mise à jour le 22 août 2018