GUADIANA BASIN Water quality and the development of the Alqueva region Report of the NeWater project - New Approaches to Adaptive Water Management under Uncertainty www.newater.info Title Purpose Inventory and analysis of the pollution sources in the Guadiana basin as a tool for the future development of the Alqueva region. Filename Guadiana Basin water quality Authors Marco Estrela, Eduardo Silva Document history Current version. Final Changes to previous version. Date 19 January 2009 Status Final Target readership General readership Correct reference Marco Estrela, editor Instituto de Soldadura e Qualidade January 2009 Prepared under contract from the European Commission Contract no 511179 (GOCE) Integrated Project in PRIORITY 6.3 Global Change and Ecosystems in the 6th EU framework programme Deliverable title: Report on Water quality and the development of the Alqueva region Actual submission date: 10.01.2009 Start of the project: 01.01.2005 Duration: 4 years i Table of contents 1 Guadiana basin ..........................................................................................................................1 1.1 Water quality under the scope of international basins .....................................1 2 Water quality issues ................................................................................................................3 3 Inventory of Pollution Sources ............................................................................................9 3.1 Point Sources .....................................................................................................................9 3.2 Diffuse sources ...............................................................................................................33 4 Water Quality Analysis .........................................................................................................45 5 Conclusion .................................................................................................................................56 6 List of references ....................................................................................................................58 ii 1 Guadiana basin The Guadiana river is an international basin with a total area of 66 860 km2, having it is headwaters in Spain with a basin of 55 260 km2. The national area has 11 600 km2 and a big dam was built, Alqueva, creating a reservoir with 250 km2 and a storage capacity of 4150 hm3. The main tributaries in the Portuguese part are the Caia, Degebe, Cobre, Vascão and Odeleite rivers, all located in the right margin, and Ardila and Chança rivers located in the left margin. The Guadiana River has an important role in the south of Portugal, a region with drought problems. 1.1 Water quality under the scope of international basins Raising awareness that the protection and use of transboundary water streams are important and urgent tasks that can only be successfully be carried out with the cooperation of the involved countries originated several actions and promotion of studies to reach those objectives. The quantity and quality of water reaching the border will be determinant to assure the quality objectives that will allow current and future water uses. Therefore it is necessary to implement bilateral studies that allow characterizing international basins as a whole, namely regarding the different pollution sources, existing water uses and the ecosystems specificities in order to achieve a diagnostic of the current situation and to define the needed measures that allow reaching the defined quality objectives. The quality objectives to be set on the transboundary basins water are a result of those that were set regarding the border stretches and from the knowledge that exists regarding the most common uses and most characteristic fish species. Figure 1 shows a map with a proposal for water quality objectives in the Guadiana basin. Although the poor water quality that reaches the border, the Portuguese basin also has some important pollution sources. These can be distributed as 35 per cent urban discharges, 39 per cent animal feedlots sector and 18 per cent food production. Many of these discharges do not have any treatment which causes a large amount of nutrients exportation to the water and soil. On the other hand, agricultural activities and animal production have a great impact in this basin as non-point pollution sources. During the last years, algae bloom occurred in several reservoirs that are spread all over the watershed, and in even in the Guadiana river, showing that this basin has already eutrophication problems. According to Article 5 and Annex II of the Water Framework Directive (WFD) is required that Member States identify significant anthropogenic pressures on river basins and also assess the potential impact of these pressures on the water bodies. The following areas have to be identified: point and diffuse sources pollution, the water abstraction, the water flow regulation, the morphological alterations and land use patterns. 1 Objectives: Good - Bathing water A2 – production of drinking water Good - Fish waters - cyprinids Figure 1: Water quality proposal (source: ) For a correct basin management, it is necessary to minimize these impacts, with action plans and monitoring programmes, to improve water quality and achieve the environmental objectives. 2 2 Water quality issues The Guadiana River and its affluent are characterized by a flow regime with strong inter-annual variation and strong seasonal character, with long periods of reduced flow. These flow characteristics associated with conditions of high temperatures and significant pollutant discharges gave origin to a system with “strong” pollution and signs of eutrophication, where severe algae blooms frequently occur and subsequent death of aquatic fauna. This aspect is particularly evidenced at the end of Summer/beginning of the raining season, which run-off causes leaching of the soil and transport of sediments accumulated during the dry season, at the bottom of the tributaries bed, added to the agro-industry wastewater, inevitably causes the fast increase of the pollutant load. It is important to understand the schematic representation of the Guadiana River and its tributaries, which is represented in Figure 2. We should then analyse the evolution of the water quality along the Guadiana River as well as estimate the origin of the main factors leading to its degradability. It is known that the Guadiana River when entering the Portuguese territory already presents a considerable pollution level. Note that 83% of the Guadiana River Basin is on Spanish territory and that the demographic, industrial and agricultural occupation is substantially higher then the one in Portuguese territory. A significant set of polluting units although of small/medium size and connected to farming, cattle and mining activities also exist in the Portuguese part of the basin. This fact is worsened by the hydrological deficit registered during summer season, during which the water lines where no dam is built have very low flows or no water. Several studies have been made during the years to identify and inventory the pollution sources at the basin. All of them point out as the main pollution sources a pulp and paper plant at Mourão, the mining of minerals, the agricultural and cattle breeding activities, wastewater, and use of fertilizers. For and easier interpretation of the data in this study the Guadiana basin was divided in physiographic units, considered as homogeneous areas having as a basis the hydrographical limits of the basins and the geological, hydrogeological, geomorphological, and environmental characteristics. Data will be then presented having these physiographic units into account being them: • Zone A, corresponding to the Portuguese area of the Guadiana basin north of the Degebe and Ardila river basins; • Zone B, corresponding to the Degebe and Ardila river basins; • Zone C, corresponding to the Guadiana basin between those two basins and the limit of the Guadiana basin defined by the Pulo do Lobo section; • Zone D, corresponding to the remaining Portuguese part of the Guadiana basin, from Pulo do Lobo section until the estuary. 3 Guadiana (Spain) Xévora 1 Reservoir Caia 1 Water quality stations Caia 1- Caia 8- Monte Clérigo Mures and Monte da 2- Lucefécit 9- Boavista Asseca Vinha 3- Vigia 10- Oeiras Lucefécit 2 4- Monte Novo Lucefécit 5- Alqueva 11- Guadiana (Chança) Azeval e Alamo Vigia Alcarrache Vale Vasco 3 Azenha de Cerieiros Degebe 5 4 Ardila Monte Novo 6 Vale da Serra Pias Marmelar, Odearça e Amoreira 7 Enxoé Terges Limas 8 Cardeira e Cobres 9 Oeiras 10 Rocha da Galé Rocha da Nora Carreiras Chanza 11 Vascão e Alcoutim Cais de Foupana Alcoutim 12 Odeleite Beliche 13 Estuary Figure 2: Schematic Representation of Guadiana River and its tributaries 4 Each of these large areas were sub-divided in smaller areas, having as a basis the limits of hydrographical sub-basins defined by the sections of water lines selected according to the following criteria: • Confluence between main water lines; • Location of main dams; • Location of hydrometrical stations; • Location of main wastewater discharge points. Following these principles, 52 physiographical units were established, numbered from North to South as follows: • Zone A – 9 physiographical units, from A1 to A9; • Zone B – 16 physiographical units, from B1 to B16; • Zone C – 14 physiographical units, from C1 to C14; • Zone D – 13 physiographical units,