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
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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.
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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.
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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.
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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
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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, from D1 to D13. For a better understanding of this division please see Figure 3.
In this analysis of the water quality of the Guadiana and its tributaries we also took into account the sensible areas of the basin. These are determined according the Decree law n. 152/97, of 19 June, that transposes the Council Directive 91/271/CEE, that establishes the general conditions regarding collection, treatment and discharge of urban wastewaters into the aquatic medium.
This Decree law also defines the deadlines for the operation of drainage systems e for the installation of adequate treatment, population dimensions to which it applies and procedures of analytical control for the discharges made in those zones.
Therefore a certain water extension will be identified as Sensible Zone if it belongs to one of the following categories:
• Natural freshwater lakes, other freshwater extensions, estuaries and coastal waters that are eutrophic or are prone to become eutrophic in the near future if protection measures are not taken; • Surface water for abstraction of potable water, which nitrates content may exceed the nitrates concentration established in the 75/440/CEE Directive of 16 July, regarding the quality of surface water for production of potable water if protection measures are not taken; • Areas where other treatments beyond that foreseen in article 5 are needed in order to comply with the requirements of Council Directive. An extension or zone of sea water may be identified as a Less Sensible Zone if the discharge of wastewaters does not deteriorates the environment due to the morphology, hydrology or specific hydraulic conditions from that zone. When identifying those zones, the risk of transferring the discharged load to the adjacent zones where they may be harmful to the environment. The following aspects should also be considered: open bays, estuaries and other coastal waters with a good renovation and that are subject neither to eutrophication neither to oxygen impoverishment or which eutrophication or oxygen impoverishment as a sequence of urban wastewater discharges is considered to be improbable.
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Figure 3: Guadiana basin (Portuguese part) divided in Physiographic Units Six Sensible Areas were identified in the Guadiana basin:
Nr. Name Identification Section of Guadiana river from the confluence with 29 Guadiana Caia river to the confluence with Chança river. 30 Vigia Reservoir 31 Monte Novo Reservoir 32 Múrtega Múrtega creek 33 Caia Reservoir Sapal de Castro All Castro Marim marshland area and respective 38 Marim hydrographical basin Table 1- Sensible Areas in the Guadiana Basin
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We may then conclude that a significant part of the Guadiana River is a defined as a sensible zone from the moment it enters the Portuguese territory. Regarding the sub basins those may also be classified as being more or less sensible, depending this classification on their location, their water quality, volume and type of effluents that are discharged into them, existing reservoirs and water uses.
Starting with the reservoirs and water uses, the following Guadiana river reservoirs have water abstraction for domestic use:
• Caia • Alcoutim • Vigia • Boa Vista • Monte Novo • Monte Clérigo • Bufo • Lutão • Enxoé • Perreiro • Tapada Grande • Odeleite • Tapada Pequena • Beliche All these reservoirs are classified as being protected according to the Decree 2/88, of 20 January (art. 1, n. 2). According this decree (art. 7), the following constraints apply: 1 – The protection zone will have a 500m width, counted from the line of full storage (LFS) and measured horizontally; 2 – The area of the protection zone, at the reservoir margin with a width of 50m from the LFS line is considered as reserved zone, in which constructions of any kind apart those of support infrastructures to assist in the utilization of those reservoirs are not allowed. This width may be adjusted for each reservoir if that is deemed convenient according to the land management of the protection area. 3 – The areas of dams and safety organs and use of public waters reservoirs will be established by ministry dispatch and will be part of the classified reservoir protection areas. 4 – Fishing, bathing and swimming are allowed with restrictions; 5 – Motor navigation is not allowed. 6 – Sporting events with motor boats are forbidden, being the remaining allowed with restrictions.
This study has been divided in five phases: Inventory of pollutant sources; Determination of polluting sources; Analysis of water quality; Determination of the polluting sources that contribute most to the degradation of water quality; Conclusions.
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The presented values are estimates which rigour is dependant of the inventoried data that present several flaws (PBH Guadiana):
Inventory data from several sources; Data lacking in the inventory (pollutant loads, industrial production, number of workers) of most industries (88%) namely for “Other food industries” and “Other industries”; Inconsistent inventory data for many industries; Duplication of inventory for some industries; Missing information regarding production processes of some industries (leather) Some production data are aggregated for some industries. The referred flaws translate in a lack of rigour that the estimation of industrial pollutant loads in the basin will be carrying, particularly in terms of the geographical spacialization.
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3 Inventory of Pollution Sources
3.1 Point Sources
3.1.1 Urban Origin Urban effluents have little significance regarding water quality problems at the Guadiana basin. This is due not only to the difference in polluting loads between these sources and the industrial ones that are substantially higher, but also to the fact that the population density in this region is the country lowest. However, due to its deficient or in some cases inexistent treatment the contribution to the degradation of water quality increases significantly. When the Guadiana basin management plan was done some 178 wastewater systems existed in Portuguese territory, 30 of which did not have any treatment of the final effluent. Presently this scenario is a little different. However due to the lack of existing data in this area, in this work we have used data presented in the Guadiana management plan The following effluent treatment are distributed in the basin Primary decanting – 21 units; Biological disks – 8 units; Septic tank – 37 units; Grading – 4 units Stabilization lagoons – 20 units; Anaerobic lagoons – 2 units; Activated sludge – 2 units Percolation beds – 10 units Imhoff Tank – 1 unit; Unknowns – 43 units; Total – 148 units. The following percentages referring to the efficiency of treatment were used in this study:
Efficiency of Treatment % Type BOD/COD N P Septic tank 30 15 20 Primary decanting 30 10 20 Imhoff Tank 30 15 20 Conventionally activated sludge 90 25 20 Activated sludge by long aeration 90 30 25 Lagoons 90 50 40 Percolation beds 75 25 10 Table 2 – Efficiency of different wastewater treatment technologies
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Regarding the population served by wastewater systems we conclude that: 86% of the population is served, of which 62% have treatment and 24% do not have; 14% of the population is not served by wastewater treatment systems, a large part corresponding to isolated population. The evaluation of urban effluents considered the loads of urban effluents by inhabitant, defined in the literature for the Southern Portuguese case, applied either to the population served by wastewater treatment systems either to the population that is not served. Therefore the unit loads applied were the following:
BOD 5 = 60 g/inhab. COD = 120 g/inhab.
Ntotal = 10 g/inhab.
Ptotal = 2 g/inhab. Dilution or concentration of the calculated loads in the final effluent is given by the comparison of these with the water use (bills), corresponding to the populations and systems being analysed, affected by a 80% coefficient. Figure 4 shows the location of main treatment stations existing in the Guadiana basin.
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Simbology Guadiana hydrological limit
Hidrographical network Border between Alentejo and Algarve regions
Parish headquarters Chlorination point Water treatment station Figure 4: Water treatment stations and chlorination points (source: PBH Guadiana)
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3.1.2 Industrial Origin (Industries connected to agricultural and animal production) Industries from the agricultural and animal production sectors whose effluents are connected to wastewater systems were not considered pollutant sources of industrial origin but included in the group of pollutant sources of urban origin. We considered that those industries that discharge directly to the water lines do not have any type of treatment and therefore do not have any type of pollutant reduction. Types of inventoried industries are presented in the following table together with the analysed pollutants:
Analysed Parameters Industry Type Total Faecal BOD COD TSS N P 5 coliphorm coliphorm Olive oil √ √ √ mills/refineries Piggeries √ √ √ √ √ √ √ Bovine production √ √ √ √ √ Poultries √ √ √ √ Wine cellars and √ √ √ distilleries Animal slaughtering √ √ √ √ √ and meat processing Fish transforming industries and √ √ √ aquacultures Fruits and vegetables √ √ √ processing industries Production of mineral water and √ √ √ √ non alcoholic beverages Dairy √ √ √ √ √ Cereals and beans transforming √ industries Other agro food √ √ √ units Table 3 – Industries inventoried and respective pollutants
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The following table shows the considered working times for each industry type:
Industry Type Annual working period Olive oil mills/refineries 45 days Wine cellars and distilleries 180 days Fruits and vegetables processing 66 days industries Remaining industries 365 days Table 4 – Work times in selected industries Next we analyse the industry types associated to this sector.
a) Olive oil mills/refineries The Guadiana basin has around 135 olive oil mills/refineries and one vegetable oil plant. Only 25 of those are connected to wastewater networks being located mainly in the Campo Maior, Elvas, Serpa and Moura parishes. Therefore there are 108 mills and one vegetable oil plant discharging directly to the water line in the Serpa, Portalegre, Moura, Redondo, Elvas and Portel parishes. Figure 5 and Figure 6 show the distribution of olive oil mills in the Guadiana basin. ●●● ● ● ● ●
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Figure 5: Olive oil mills not Figure 6: Olive oil mills connected to wastewater connected to wastewater networks (Source: PBH Guadiana) networks (Source: PBH Guadiana)
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In general they are installations that operate seasonally, around 45 days per year and with a small amount of raw material. However, we should note that the largest installations of the country are located in Beja district (with an average value of 2575 hl/mill), Évora (1775 hl/mill) and Portalegre (1413 hl/mill).
The total pollutant load of these installations is shown next:
Parameters Per kg of treated olive/day TSS 27 g
BOD 5 22 g COD 32 g Table 5 – Pollutant loads of olive oil mills
Considering an average production capacity of 11 ton, the pH of these wastewaters is 4 to 5 and the produced volume per kg of olive is:
Kg of processed olive Effluent volume(l) Traditional Process 0,5 a 0,6 Continuous Process 1,3 a 1,4 Table 6 – Effluent volume of olive oil mills
b) Piggeries 253 piggeries are located in the area being analysed 2 of which are connected to sanitary networks located in Beja and Alandroal. Therefore 251 piggeries are discharging directly to the water line. These are located mainly in the parishes of Reguengos, Évora, Redondo, Alandroal, Reguengos de Monsaraz, Beja and Elvas. The distribution of piggeries in the Guadiana basin is shown in Figure 8 and Figure 7. ● ● Figure 8: Piggeries connected to Figure 7: Piggeries not connected wastewater networks (Source: to wastewater networks (Source: PBH) Guadiana) PBH)
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These units produced wastewater volumes depends mainly on the volume of manure, type of piggery and number of washings performed. We considered, according to law nr. 810/90, a production of 12 l/animal equivalent.day, where one animal corresponds to:
a.e. in closed cycle Nr. of pigs x 10 a.e. in multiplication Nr. of pigs x 4 a.e. in fattening Nr. of pigs x 1,5 Table 7 – Animal equivalents in different production stages
The following table presents an estimate of the pollutant loads in piggeries effluents:
Parameters Per animal of 45 kg/days TSS 180 g VSS 160 g
BOD 5 120 g COD 300 g
N total 15 to 18 g
Ammonium 9 g Total phosphorous 4 to 6 g Potassium 8 g Total coliphorm (0,06 to 0,42) x 10 9 Faecal coliphorm (0,04 to 0,13) x 10 9 Table 8 – Pollutant loads in piggeries effluents
c) Bovine production The area being analysed has 65 bovine production sites one of which is connected to a sanitary network located in Alandroal. 64 sites are discharging directly to the water lines. These are mainly located in the parishes of Évora, Redondo, Elvas and Alandroal and are usually of medium size. Figure 9 and Figure 10 shows the distribution of bovine production in the Guadiana basin. Following table presents the pollutant loads of effluents associated to each animal:
Parameters Per animal of 350 kg/day TSS 1 500 g
BOD 5 450 g COD 2 250 g
N total 105 g
N ammonium 54 g Total phosphorous 4 g Table 9 – Pollutant loads associated to each bovine
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The volume of wastewater of this activity depends essentially of the manure volume, exploration type and of number of washings performed. The adopted value was 35 l/a.e.day. ●
Figure 9: Bovine production Figure 10: Bovine production sites connected to wastewater sites not connected to wastewater networks (Source: PBH) networks (Source: PBH) d) Poultries
Ten poultries were inventoried (7 of chicken, one of turkeys, one of partridges and one of rabbits) of which one is connected to a sanitary network located in the Beja parish. The distribution of poultries in the Guadiana basin is presented in Figure 12 and Figure 11. Nine poultries discharge directly to the water line. These are located essentially in the Beja, Borba and Moura parishes and are in general medium sized installations. Following table presents the pollutant loads of effluents associated to each animal (chicken) adopted in this study:
Parameters Per animal/day TSS 40 g
BOD 5 5 g
N total 3 g Potassium 1,1 g Total phosphorous 2 g Table 10 – Pollutant load associated to each chicken
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Regarding the remaining animals we considered that the pollutant load is similar to the one produced by chickens except the BOD 5 produced by turkeys that is about 20% higher and partridges that will correspond to 1/3 of each value above presented. The volume of wastewater from poultries depends essentially on the number of animals, installation type and number of washings made. The value considered in this work was 2 l/a.e.day (except for partridges). ● ●
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● Figure 12: Poultries not Figure 11: Poultries connected to wastewater connected to wastewater networks (Source: PBH) networks (Source: PBH) e) Distilleries and wine cellars
The area being analysed ahs 28 distilleries/wine cellars, three of which located in Borba and Redondo parishes are connected to the wastewater systems.
The distribution of distilleries and wine cellars in the Guadiana basin are presented in Figure 13 and Figure 14.
Twenty five distilleries/wine cellars discharge directly to the water lines. They are located mainly in Reguengos de Monsaraz, Vidigueira, Alcoutim, Campo Maior, Elvas, Mourão, Redondo, Moura and Reguengos parishes, and are generally small installations. The large cellars in the area have ceased wine distillery.
Regarding the volume of effluents produced by the wine industry and its derivates we adopted the following values: 1,5 m 3 per ton of pressed grape, in wine production; 11,5 m 3 per m 3 of produced pure alcohol, in wine sludge distillation; 7,5 m 3 per m 3 of produced pure alcohol, in wine distillation.
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As average, one ton of pressed grapes originate 750L of wine being the pollutant loads of:
Parameters Per kg of pressed grapes /day TSS 0,6 g
BOD 5 4,5 g COD 7,5 g Organic matter 5,5 g Table 11 – Pollutant loads of grapes pressing (wine production)
For the brandy distilleries the following pollutant load values were adopted in the effluents due to one litre of produced pure alcohol:
Parameters Per L of pure alcohol/day TSS 2,4 g
BOD 5 94,6 g COD 217,9 g Organic matter 135,6 g Table 12 – Pollutant loads of distilleries ● ● Figure 13: Distilleries not Figure 14: Distilleries connected to wastewater connected to wastewater networks (Source: PBH) networks (Source: PBH)
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f) Animal slaughtering and preparation and production of processed meat
The area being analysed has 36 units of this type neither of which is connected to a drainage system. Figure 16 and Figure 15 show the distribution of these industries in the Guadiana basin.
Beja’s slaughterhouse is the main one in the region with the remaining units dispersed in the basin area.
For this industry we applied the following values:
Flow 47 (m 3/worker. Month)
BOD 5 1 500 mg/l
Nammonium 45 mg/l
Ntotal 75 mg/l COD 3 000 mg/l Total phosphorous 25 mg/l Oils and greases 500 mg/l TSS 1 000 mg/l Table 13 – Pollutant loads of slaughterhouses Figure 16: Industries producing Figure 15: Animal slaughtering and animal feed compounds not processed meat industries not connected to wastewater networks connected to wastewater networks (Source: PBH) (Source: PBH)
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g) Production of mineral waters and non-alcoholic beverages
Two installations of this type exist in the area none of which is connected to drainage network therefore discharging to the water lines. They are located in Campo Maior and Beja (see Figure 17).
The pollutant load produced is as follows:
Flow 13 m 3/work.month
Nammonium 5 mg/l
Ntotal 40 mg/l
BOD 5 4 000 mg/l COD 7 000 mg/l Hydrocarbons and mineral oils 20 mg/l Phenol 0,1 mg/l Detergents 0,15 mg/l Total phosphorous 5 mg/l Oils and greases 60 mg/l TSS 600 mg/l Table 14 – Pollutant loads of mineral water and non-alcoholic beverages production ● ● Figure 17 - Mineral water and non alcoholic beverages production not connected to wastewater networks (Source: PBH) h) Other agro-food industries
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Of the 292 industries existing in this area 181 are connected to wastewater systems. • Twenty fruit and vegetables preserving industries of which one located in the Borba parish is connected to the drainage system. • Thirty five dairy industries 2 of which are connected to drainage systems. • Eleven cereals and beans industries 9 of which are connected to drainage systems. • Three fish processing plants, none of which is connected to a drainage system. • Thirteen animal food processing industries, none of which is connected to a drainage system. • 210 of other agro food industries 169 of which are connected to drainage systems. The distribution of these industries is shown in Figure 19 and Figure 18. Figure 19: Other agro food Figure 18: Other agro food industries connected to industries not connected to wastewater networks (Source: wastewater networks (Source: PBH Guadiana) PBH Guadiana) h.1) Fish processing industries In the Guadiana region these activities are concentrated at the river estuary close to Vila Real de Santo António. The distribution of these industries in the Guadiana basin is shown in Figure 20. The estimated pollutant loads for this activity are the following:
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Flow 13 m 3/worker.month
BOD 5 500 mg/l COD 1000 mg/l Oils and greases 150 mg/l TSS 500 mg/l Table 15 – Pollutant loads of fish processing industries
Figure 20: Fish processing industries not connected to wastewater networks (Source: PBH Guadiana) h.2) Food and vegetables preserving industries The distribution of these industries in the Guadiana basin is shown in Figure 21 and Figure 22. The estimated pollutant loads for this activity are the following:
BOD 5 1 004 Kg/worker.year TSS 226 kg/ worker.year Table 16 – Pollutant loads of food and vegetables preserving industries
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h.3) Dairy industries Milk production presents as would be expected some environmental problems that when tried to solve lead sometimes to problems in product quality. The application of internal measures of effluents recycling and reuse are therefore very limited. There is no alternative but to treat the effluents which are characterised by a high organic load. The distribution of these industries in the Guadiana basin is shown in Figure 23 and Figure 24. The estimated pollutant loads for this activity are the following:
Flow 47 m 3/worker.month
Nammonium 45 mg/l
Ntotal 75 mg/l
BOD 5 1 500 mg/l COD 3 000 mg/l Total phosphorous 25 mg/l Oils and greases 500 mg/l TSS 1 000 mg/l Table 17 – Pollutant loads of dairy industries
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h.4) Other food production industries: Bread and pastry
Flow 7 m 3/worker.month
BOD 5 500 mg/l COD 1 000 mg/l Oils and greases 50 mg/l TSS 600 mg/l Table 18 – Pollutant loads of bread and pastry production
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3.1.3 Industrial Origin Following table presents the types of inventoried industries as well as the analysed pollutants: Analysed parameters Industry type BOD 5 COD TSS N Mining industries X X X X Leather industries X X Others X X X Table 19 – Types of inventoried industries and respective pollutants
a) Stone mining and other mining explorations 250 units connected to the mining industry were inventoried in the area being studied, 194 stone mines and 56 mine explorations, none of which is connected to wastewater systems. Figure 25 shows the distribution of the main stone mines and other mining explorations in the Guadiana basin. This type of activity has very different situations namely: • Installations for extraction and finishing of decorative stones where the generated pollution is mainly due to the suspended solids that goes to their wastewater systems; • Abandoned ore extraction installations which produced pollution is due to the run offs that are in this study included in diffuse pollution category; • Mining installations in operation. • Stone mining is a relatively low pollutant activity by itself. However the industrials pump the flows (liquid and gaseous)
Most environmental problems that are faced today are due to cease of operation of many mines without having been taken the needed mitigation actions. The main problem occurs in sulphur mines where the pollutant agent is the acid waters that cause the increase in water acidity (frequently with a pH<3), the increase in metals solubility, some with toxic effects (like lead, cadmium, arsenic, mercury, zinc, etc.) and the decrease in dissolved oxygen (increase of COD).
Mining exploration in this basin was very intense but at present the only relevant industry is the Neves Corvo copper and zinc mines. Therefore we have just estimated the point source pollution generated at this site. The residual water has two main origins: the infiltration water at the mine bottom and the process water from the ore treatment.
Water from the mine bottom is treated in a WWTP, goes through a biological filter to remove heavy metals and is then discharged in the Oeiras Creek. Ore treatment process water goes to two lagoons where the suspended solid particles sediment. This water is partly recovered to satisfy the mine needs and the remaining is lost by evaporation/infiltration at the lagoons.
The estimation of pollutant load of the wastewater rejected to Oeiras creek was made taking in consideration the results of samplings made there. The waste
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water flow is on average of 4295 m 3/day with the following pollutant concentrations:
Parameter Concentration
BOD 5 3,0 mg/l COD 6,6 mg/l N 8,9 mg/l TSS 4,5 mg/l Table 20 – Pollutant concentrations in wastewater rejected to Oeiras creek.
Figure 25: Stone mining and other mining explorations not connected to wastewater networks (Source: PBH Guadiana) b) Leather tanning industry
Twenty one industries related with leather tanning were inventoried in the study area, 6 of which are connected to the drainage system. Therefore 15 installations directly discharge to the water lines, being 7 industrial leather tanning installations and 8 are industrial installations that work with leather only. These are located mainly in the Elvas parish. The distribution of these industries in the Guadiana basin is shown in Figure 26 and Figure 27. Water consumption, and consequently the effluent volume, in this type of industry is almost always very high. On average the volume of water needed per Kg of processed leather varies between 15 and 100 L, 40% to 50% of which are washing waters that are low polluting.
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Following table present an estimate of the pollutant loads for this industry:
Process Parameters Average Value pH 11 TSS 3 240 mg/l TDS 12 200 mg/l BOD 9 500 mg O /l Vegetal tanning 5 2 Sulphurides 120 mg/l Greases 620 mg/l Average volume of 12 m 3/ton gross leather residual water pH 11 TSS 4 970 mg/l TDS 16 000 mg/l BOD 970 mg O /l Mineral tanning 5 2 Sulphurides 125 mg/l Greases 600 mg/l Average volume of 64 m 3/ton gross leather residual water Table 21 – Pollutant loads of leather tanning industry Figure 26: Leather tanning Figure 27: Leather tanning industries not connected to industries connected to wastewater networks (Source: wastewater networks (Source: PBH Guadiana) PBH Guadiana)
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c) Other industries
852 industries were inventoried in the area being studied, 769 of which are connected to sanitary systems, most of them being of small or medium size. Therefore 83 industries discharge their effluents directly to the water lines. Their distribution may be seen in Figure 28 and Figure 29. Figure 28: Other industries not Figure 29: Other industries connected to wastewater connected to wastewater networks (Source: PBH networks (Source: PBH Guadiana) Guadiana) Figure 30 to Figure 35 shows the maps corresponding to annual loads of BOD5, COD, nitrogen, phosphorus, TSS and Coliphorm existing in each Guadiana river sub basin.
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Figure 30: Point source pollution BOD5 load per sub basin (source: PBH Guadiana)
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Figure 31: Point source pollution COD load per sub basin (source: PBH Guadiana)
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Figure 32: Point source pollution Nitrogen load per sub basin (source: PBH Guadiana)
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Figure 33: Point source pollution Phosphorus load per sub basin (source: PBH Guadiana)
30
0
Figure 34: Point source pollution TSS load per sub basin (source: PBH Guadiana)
Class 1 Class 2 Class 3 Class 4 Class 5
Class Faecal Coliphorms Total Coliphorms 1 Not significative Not significative 2 <5,0x10 12 < 2,0x10 12 3 5,0x10 12 – 4,0x10 13 2,0x10 12 – 1,7x10 14 4 4,0x10 13 – 1,5x10 14 1,7x10 14 – 6,5x10 14 14 14 5 > 1,5x10 > 6,5x10
Figure 35: Point source pollution – Faecal and total coliphorm load per sub basin (source: PBH Guadiana)
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3.1.4 Conclusions Regarding the estimated daily loads we may conclude that:
Organic pollution (BOD 5 and COD) problems are mainly due to olive oil mills/refineries and piggeries; Regarding nutrients (nitrogen and phosphorus) the industries connected to animal production are the most polluting ones. The largest daily discharges of nitrogen have origin in the Neves Corvo mines, piggeries and cattle breeding and those of phosphorus in the piggeries and birds breeding; Olive oil mills/refineries and piggeries are the industrial activities with a larger weight in the production of total suspended solids; Piggeries are the main responsible for contamination with total and faecal coliphorms, with an estimated total daily average weight of 5 x 10 13 e 1 x 10 13 for the whole basin in Portuguese territory.
Regarding the average loads generated in the sub basins it is of note:
In what concerns pollution with organic (BOD 5 and COD) origin the most problematic areas are located in the sub basin where a paper mill was located, Caia sub basin (olive oil mills) and Lucefécit (piggeries), and at the Odearça creek (piggeries). In terms of nutrients (nitrogen and phosphorus) the worst sub basins include the Lucefécit up stream of the reservoir, Odearça and Cardeira creeks and the left bank of the Degebe downstream the Monte Corvo dam and in the Oeiras creek. Total suspended solids are mainly generated in the Caia and Lucefécit rivers and Odearça and Cardeira creeks. Coliphorm contamination is significant in Lucefécit, Odearça and Cardeira basins and Asseca sub basin. Following table shows the comparison of average annual pollutant loads of industrial origin.
BOD N P Water course 5 (t/year) (t/year) (t/year) Xévora river 31 11 7 Caia river and Lã creek 1 689 24 8 Mures and Asseca creeks 622 90 30 Lucefecit creek 805 165 73 Degebe river 951 130 44 Ardila river 194 40 20 Odearça and Cardeira creeks 1 098 242 97 Oeiras creek 803 13 943 0 Guadiana basin in Portugal 303 104 14 849 350 Table 22 – Average pollutant loads in Guadiana watershed
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3.2 Diffuse sources We can synthesize the main characteristics of diffuse pollution as follows:
The discharges reach the surface waters in a diffuse and intermittent way, being fundamentally related with the occurrence of uncontrollable meteorological phenomena. The intensities of discharges depend essentially of the rain water volume and of the duration of the previous dry season. The discharges have origin in a large area and cannot generally be characterised in the source point of difficult definition.
Because the Guadiana basin has a rural character, the main sources of diffuse pollution in the basin are those of agriculture origin and those from livestock production processes.
Regarding diffuse pollution with urban origin (residential and industrial) the most important are those from abandoned mines.
Therefore and for the analysis of current situation the following diffuse pollution sources were analysed:
Rural origin: Flow of irrigation waters; Run off from forest and pasture areas; Run off from animal production activities;
Urban/industrial origin: Flows from residential and industrial areas; Flows from abandoned mines;
3.2.1 Rural origin Rural sources (agriculture or other) of diffuse pollution include the ones resulting from:
• Fitosanitary practices and adubation of irrigated cultures; • Pollution associated with soil erosion of the remaining rural area; • Flows of wastes from animal production activities; a) Irrigated areas
The irrigated area belonging to the Guadiana basin is estimated to be around 29130 ha, which is only 3,6% of the useful agricultural surface (UAS). Following table shows the irrigated areas as well as the crops with largest irrigated areas, described by parish:
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Irrigated area Crops with Parish % UAS (ha) largest area Alandroal 1 730,2 3,8 Orchards Alcoutim 46,2 0,0 Citrus Almodôvar 6,4 0,0 Fodder Arraiolos 345,7 11,3 Fodder Arronches 470,3 1,5 Olive trees Barrancos 4,0 0,0 Citrus Beja 4 122,3 6,7 Citrus Borba 440,3 4,2 Orchards Campo Maior 3 251,9 12,7 Corn Castro Marim 513,7 0,1 Citrus Castro Verde 210,8 0,4 Citrus Cuba 300,0 8,5 Citrus Elvas 5 860,7 11,0 Corn Estremoz 29,5 0,4 Fodder Évora 3 718,0 6,7 Fodder Loulé 131,3 0,5 Citrus Mértola 100,0 0,0 Orchards Monforte 126,6 3,2 Olive trees Moura 551,2 0,8 Fodder Mourão 214,5 0,8 Fodder Ourique 0,4 0,0 Fodder Portalegre 312,2 0,5 Fodder Portel 1 337,3 3,1 Sun flower Redondo 1 051,7 3,0 Corn Reguengos 978,5 2,2 Fodder S.B. Alportel 74,8 0,1 Citrus Serpa 1 867,2 2,1 Fodder Tavira 203,9 0,1 Citrus VRS António 653,7 2,0 Citrus Vidigueira 136,7 0,3 Citrus Vila Viçosa 340,6 1,0 Corn Total 29 130,0 3,6 Table 23 -Size of irrigated areas and crops with largest areas
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Campo Maior, Arraiolos and Elvas are the regions with highest vulnerability to contamination of water resources, while this problem has no significance in the parishes of Almodôvar, Barrancos and Ourique.
To estimate the nutrients exporting risks we used the exporting rates (developed by Jorgense, 1980) as a function of agricultural occupation.
Agricultural Phosphorus exporting Nitrogen exporting occupation rate (mg/m2.year) rate (mg/m2.year) Orchards 18 2 240 Pasture 15 75 100 – 850 Cereals and e oil crops 22 100 500 – 1 200 Table 24 – Exporting rates as a function of agricultural occupation The largest phosphorus exporting risks are in the Xévora and Caia sub basins and in the Guadiana right margin, between the Portuguese border and the section downstream the Mures creek. Areas with largest risk include the Cobres river and the Oeiras, Carreiras, Vascão and Odeleite basins.
Regarding the nitrogen loads produced in irrigated areas, those are higher in the sub basins of Caia river and the right margin of the Guadiana river between the Odearça and Cobres rivers.
The contribution to water quality of nitrogen and phosphorus in the irrigated areas is shown in Figure 37 and Figure 36. This problem is more evident in the Caia, Degebe and Odearça sub basins.
PI < 70% PI < 25% 25
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b) Remaining Rural Areas This problem reaches highest proportions in the Caia, Degebe and Odearçs sub basins. c) Wastes from animal production activities
Although these activities are included in the group of point source pollution they may also become important diffuse pollution sources.
Areas with largest risks include the Guadiana river sub basin up stream the Lucefécit river junction and the Caia sub basin immediately up stream the Caia dam.
This risk is negligible in some sub basins of the left margin of Cobres creek, at the sub basin immediately up stream the Odeleite dam and in the Ardila sub basin.
Figure 38 show the annual average pollutant load originating from the animal production activities. Sub basins are classified in 5 classes according to the concentration of several parameters presented in following table.
BOD 5 N P Total Coliphorm Faecal Coliphorm Classes (t/year) (t/year) (t/year) (10 6 MPN/year) (10 6 MPN/year) 1 <7,00 <1,00 <0,25 <7,0E+10 <2,0E+9 2 7,00–11,50 1,00–1,30 0,25–0,34 7,0E+10–1,12E+10 2,0E+9 2,65E+9 3 11,50 20,00 1,30 2,30 0,34 0,60 1,12E+10 2,0E+11 2,65E+9 4,5E+9 4 20,00 26,50 2,30 3,00 0,60 0,80 2,0E+11 2,6E+11 4,5E+9 6,1E+9 5 26,50 63,00 3,00 7,50 0,80 1,90 2,6E+11 6,5E+11 6,1E+9 1,5E+10 Table 25: Diffuse pollution originated from animal production activities
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Class 1 Class 2 Class 3 Class 4 Class 5 Figure 38 : Diffuse pollution Annual average load of pollutants coming from animal production activities run off (Source: PBH Guadiana) Conclusions
Following table show the nutrients average loads of rural origin at the different Guadiana river sub basins.
Regarding the phosphorus exporting risks the highest loads come from irrigation. However, at a significant number of sub basins the average phosphorus load originating from remaining rural areas is higher then those from irrigation areas.
Regarding the nitrogen exporting risks the highest loads are also from irrigated areas with a large contribution also from the animal production activities.
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Phosphorus average load (t/year) Nitrogen average load (t/year) Sub-basin Animal Remaining Animal Remaining designation Irrigation Irrigation production rural area production rural area
A1 18 0,21 25 167 0,82 38
A2 1 197 0,69 101 19 227 2,70 156
A3 66 0,67 116 3 635 2,61 179
A4 1 198 1,04 155 20 274 4,04 239
A5 1 659 0,81 192 23 116 3,16 296
A6 905 0,80 124 13 418 3,10 191
A7 441 1,88 120 15 729 7,33 185
A8 231 1,77 84 12 427 6,89 130
A9 102 0,78 32 12 177 3,05 49
B1 299 0,34 153 2 820 1,33 236
B2 418 1,11 154 5 250 4,33 237
B3 169 0,66 36 5 008 2,58 55
B4 393 0,49 145 4 287 1,89 223
B5 261 0,45 131 2 917 1,74 202
B6 114 0,32 63 1 074 1,24 97
B7 168 0,64 70 8 302 2,48 107
B8 365 0,55 166 4 591 2,15 255
B9 102 0,29 23 946 1,11 35
B10 91 0,48 94 856 1,85 145
B11 124 0,20 78 1 563 0,77 120
B12 38 0,19 61 356 0,75 93
B13 57 0,46 85 587 1,81 131
B14 28 0,14 74 261 0,54 114
B15 60 0,30 95 570 1,19 145
B16 48 0,34 51 481 1,31 79
C1 123 1,03 204 15 353 3,99 313
C2 109 0,72 118 2 629 2,80 182
C3 206 0,80 148 1 948 3,13 228
C4 179 0,34 151 22 224 1,31 233
C5 180 0,62 102 1 700 2,41 156
C6 47 0,17 30 442 0,65 46
C7 209 0,70 70 2 047 2,71 108
C8 198 0,57 46 1 868 2,21 71
C9 55 0,10 32 6 823 0,40 50
C10 158 0,76 142 19 680 2,96 219
C11 27 0,20 38 3 395 0,79 58
C12 24 0,48 92 2 991 1,88 141
C13 3 0,08 11 407 0,32 17
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Phosphorus average load (t/year) Nitrogen average load (t/year) Sub-basin Animal Remaining Animal Remaining designation Irrigation Irrigation production rural area production rural area
C14 6 0,29 36 688 1,11 56
D1 10 0,75 58 1 282 2,91 88
D2 21 0,63 83 619 2,47 128
D3 2 0,33 29 260 1,30 44
D4 1 0,41 12 5 1,60 18
D5 4 0,76 51 464 2,95 78
D6 3 0,32 31 339 1,25 48
D7 6 1,04 31 675 4,04 48
D8 24 0,95 70 2 928 3,71 108
D9 3 0,29 26 420 1,14 29
D10 18 0,57 81 2 275 2,20 124
D11 17 0,17 13 2 171 0,64 20
D12 30 0,21 70 3 711 0,80 107
D13 85 0,26 30 10 546 1,01 47
Table 26: Nutrients average loads of rural origin at the Guadiana sub- basins
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3.2.2 Urban origin Regarding diffuse pollution with urban origin, Figure 39 shows the average annual pollutant loads in each of the Guadiana river sub basins. Sub basins are classified in 5 classes according to concentrations of several parameters:
BOD 5 N P TSS Classes (t/year) (t/ year) (t/ year) (t/ year) 1 <3,00 <0,52 <0,14 <62 2 3,00 – 6,00 0,52 – 1,05 0,14 – 0,27 62 – 124 3 6,00 – 10,00 1,05 – 1,70 0,27 – 0,45 125 – 205 4 10,00 – 20,00 1,70 – 3,30 0,45 – 0,90 206 – 390 5 >20,00 >3,30 >0,90 >390
Table 27: Diffuse pollution with urban source. Classification of the sub- basins according to annual average pollutant loads a) Urban use
In terms of pollutant exporting risks (t/ha.year) generated in urban areas, most problems are present in the Vascão and Odeleite sub basins and in the Guadiana area at the junction with Lucefécit creek. b) Abandoned mines
Seven old mines were identified in the area being studied in which acid waters are produced/ drained: Parish Mines Campo Maior Tinoca (Cu) Zambujeira (Cu) Alandroal Bugalho (Cu) Granja (Cu) Vale Covo (Pyrite) Mértola Chança (Pyrite) S. Domingos (Pyrite) Table 28 – Mines identified in the area
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Based on these field observations 1, the mines responsible for the more severe environmental degradation are those of Tinoca and S. Domingos. However the S. Domingos mines are already closed so the problems caused are only related with the flows from tailings.
Following table shows the results of the samples collected close to the Tinoca 2 mine tailings that will be used in this study: Concentrations in run-off waters Metals Cu 193 g/l Zn 61 g/l Fe 4 600 g/l Mn 24 g/l Cr 0,20 g/l Ni 0,39 g/l Cd 0,18 g/l Al 338 g/l Cations Ca 2+ 307,6 mg/l Mg 2+ 379,7 mg/l K+ 2,35 mg/l Na + 43,2 mg/l Anions Cl 260,9 mg/l
2 SO 4 6 539,8 mg/l HCO 3 0,0 mg/l Table 29: Pollutant loads produced by the mining explorations loads (Source: Guadiana hydrologic plan)
1 Fonte – “Impacte Ambiental de Antigas Minas de Sulfuretos Localizadas no Alentejo”, André Matoso, IV Simpósio Internacional de Sulfuretos Polimetálicos da Faixa Piritosa Ibérica, Jan 1998. 2 EIA Abrilongo, COBA 1983
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Class 1 Class 2 Class 3 Class 4 Class 5
Class BOD5 N P TSS (t/year) (t/year) (t/year) (t/year) 1 <3,00 <0,52 <0,14 <62 2 3,00 – 6,00 0,52 – 1,05 0,14 – 0,27 62 – 124 3 6,00 – 10,00 1,05 – 1,70 0,27 – 0,45 125 – 205 4 10,00 – 20,00 1,70 – 3,30 0,45 – 0,90 206 – 390 5 > 20,00 >3,30 > 0,90 > 390 Figure 39: Diffuse pollution – Urban areas. Pollutants annual average loads (Source: PBH Guadiana)
3.2.3 Conclusions Main conclusions are as follows: • Pollutant risks of rural origin are much higher then those of urban origin; • Regarding the pollution of rural origin we note that the main pollution source in terms of nitrogen exporting risk is the irrigation run off. • Regarding the phosphorus exporting risks although the largest polluting source originates from the irrigation areas, the major problem in several sub basins comes from the remaining rural area. • The biggest problems associated with diffuse pollution are located at the up stream sub basins, namely the Caia and Degebe rivers. • Cobres river and Oeiras creek are the sub basins where the risks of diffuse pollution are lowest.
Following table shows the estimated average pollutant loads for the Guadiana river sub basins.
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Diffuse Pollution Pollutant average loads Sub-basin 6 designation t/year 10 MPN/year Total Faecal P N BOD 5 Coliphorm Coliphorm
A1 43 206 124 7 x 10 10 1,6 x 10 9
A2 1 300 19 391 521 2,3 x 10 11 5,4 x 10 9
A3 183 3 817 563 2,2 x 10 11 5,2 x 10 9
A4 1 355 20 524 791 3,5 x 10 11 8,1 x 10 9
A5 1 853 23 418 932 2,7 x 10 11 6,3 x 10 9
A6 1 030 13 614 612 2,7 x 10 11 6,2 x 10 9
A7 564 15 925 636 6,3 x 10 11 1,5 x 10 10
A8 318 12 566 464 5,9 x 10 11 1,4 x 10 10
A9 135 12 230 183 2,6 x 10 11 6,1 x 10 9
B1 453 3 061 740 1,1 x 10 11 2,7 x 10 9
B2 574 5 492 754 3,7 x 10 11 8,7 x 10 9
B3 206 5 068 197 2,2 x 10 11 5,2 x 10 9
B4 538 4 514 698 1,6 x 10 11 3,8 x 10 9
B5 393 3 122 631 1,5 x 10 11 3,5 x 10 9
B6 177 1 174 307 1,1 x 10 11 2,5 x 10 9
B7 238 8 412 345 2,1 x 10 11 5,0 x 10 9
B8 532 4 850 791 1,8 x 10 11 4,3 x 10 9
B9 125 1 001 117 9,5 x 10 10 2,2 x 10 9
B10 186 1 005 461 1,6 x 10 11 3,7 x 10 9
B11 202 1 685 368 6,6 x 10 10 1,5 x 10 9
B12 99 451 293 6,4 x 10 10 1,5 x 10 9
B13 143 722 418 1,5 x 10 11 3,6 x 10 9
B14 102 376 352 4,7 x 10 10 1,1 x 10 9
B15 155 716 447 1,0 x 10 11 2,4 x 10 9
B16 100 562 253 1,1 x 10 11 2,6 x 10 9
C1 330 15 676 1 007 3,4 x 10 11 8,0 x 10 9
C2 228 2 815 575 2,4 x 10 11 5,6 x 10 9
C3 356 2 182 730 2,7 x 10 11 6,3 x 10 9
C4 331 22 461 724 1,1 x 10 11 2,6 x 10 9
C5 283 1 861 504 2,1 x 10 11 4,8 x 10 9
C6 77 489 147 5,6 x 10 10 1,3 x 10 9
C7 280 2 159 352 2,3 x 10 11 5,4 x 10 9
C8 245 1 943 241 1,9 x 10 11 4,4 x 10 9
C9 87 6 873 156 3,4 x 10 10 8,0 x 10 8
C10 302 19 905 700 2,5 x 10 11 5,9 x 10 9
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Diffuse Pollution Pollutant average loads Sub-basin 6 designation t/year 10 MPN/year Total Faecal P N BOD 5 Coliphorm Coliphorm
C11 65 3 455 184 6,8 x 10 10 1,6 x 10 9
C12 117 3 135 446 1,6 x 10 11 3,8 x 10 9
C13 14 424 55 2,7 x 10 10 6,4 x 10 8
C14 43 746 182 9,5 x 10 10 2,2 x 10 9
D1 69 1 374 295 2,5 x 10 11 5,8 x 10 9
D2 105 752 416 2,1 x 10 11 4,9 x 10 9
D3 32 308 156 1,1 x 10 11 2,6 x 10 9
D4 13 25 70 1,4 x 10 11 3,2 x 10 9
D5 56 546 267 2,5 x 10 11 5,9 x 10 9
D6 34 389 157 1,1 x 10 11 2,5 x 10 9
D7 38 728 187 3,5 x 10 11 8,1 x 10 9
D8 95 3 042 356 3,2 x 10 11 7,4 x 10 9
D9 30 462 135 9,8 x 10 10 2,3 x 10 9
D10 100 2 402 396 1,9 x 10 11 4,4 x 10 9
D11 31 2 191 66 5,5 x 10 10 1,3 x 10 9
D12 100 3 819 331 6,9 x 10 10 1,6 x 10 9
D13 117 10 600 186 8,7 x 10 10 2,0 x 10 9
Table 30: Estimated average pollutant loads for the Guadiana River sub basins
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4 Water Quality Analysis We used for this analysis the data collected by INAG in the following water quality monitoring stations: 20O/02 –Caia reservoir 21O/01 – Monte da Vinha 22M/01 –Lucefécit reservoir 22K/02 (S) Monte Novo reservoir (Abstraction) 22L/01 (S) Vigia reservoir (S) 24M/04 – Azenha de Cerieiros 27L/03 – Rocha da Galé 28L/03 – Rocha da Nora 29M/02 – Cais de Alcoutim The location of each station is shown in Figure 40.
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Caia reservoir
Lucefécit reservoir
Vigia Monte da reservoir Vinha
Azenha de Monte Novo Cerieiros reservoir
Rocha da Galé
Rocha da Nora
Cais de Alcoutim
Figure 40 – Surface water quality stations network (Source: SNIRH)
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These stations were chosen having into account the year of entry in function of the station, the oldest ones being chosen. Most stations started operating in 1988 with the exception of the Rocha da Galé and Rocha da Nora stations. The first one started operating in 1988 but was deactivated in 1996 which led us to choose the Rocha da Nora station that started operating in 1994 and is operating until now. The distance between these two stations is small so we used the data from both to get a more representative sample of the water quality.
We compared the data collected in the water monitoring stations with the estimated values of average annual pollutant loads in order to determine the main origins and causes of pollution observed in the Guadiana River. This analysis took into account the environmental social and economic problems caused by the degradation of the water quality along the river.
A special importance was given to the reservoirs where the main water quality problems occur. As expected the pollutants will concentrate in those places, where they sediment. It is therefore expected that the pollutant load existing in the reservoirs will be retained there with only small amounts flowing to the remaining part of the river.
Sub basins A1 and A2 were not considered in this analysis because although in the Portuguese territory the pollutant loads flow into Spanish territory. They will be accounted for with the pollutant load of Spanish origin at the Monte da Vinha station.
Due to the difficulty in explaining some of the values that are next presented, a visit was made to the area with the objective of finding an explanation for the presence of such values. Visited places included the Caia, Vigía, Monte Novo and Lucefécit reservoirs selected for the characterisation of water quality in this study and the Monte da Vinha station where the river enters Portuguese territory.
Caia Reservoir
This station is located at the Caia dam reservoir and will serve to characterise the pollutant sources included in the A3 and A4 sub basins. The pollution problems in this reservoir are evident which is aggravated by the fact that water for human consumption is abstracted here.
The water in this reservoir needs physical, chemical and disinfection treatments before being introduced in the water supply network. This problem causes problems not only in terms of public health to the population served by the water supply network but also at the economic level because the needed treatments in order to make it potable are costly.
Water for agriculture use is also abstracted at this reservoir. The same problem is found here as the water quality does not comply with the legal standards.
However the water quality has considerably improved in this reservoir in the last years namely after the national legislation regarding wastewater discharges entered in force. Until the hydrological year of 1999/2000 the reservoir is characterized as very polluted, the water being “mediocre” only potentially apt for irrigation, cooling and navigation. The reservoir was characterised as hypertrophic.
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From 2000/2001 the water quality has improved considerably but still is far from a good quality status. The reservoir is still classified as polluted, the water being of good enough for irrigation, industrial use and production of potable water after rigorous treatment. The reservoir was characterised as eutrophic.
The pollution observed in this reservoir is then essentially due to fourteen olive oil refineries that are not collected to the wastewater systems which together with the discharges from agriculture and animal production activities, namely piggeries and cattle, also not connected to wastewater systems, substantially degrade the water quality.
Point source pollution of industrial origin produced in these sub basins, including animal production, has an important expression regarding the global pollutant loads in the Portuguese Guadiana basin. As may be observed with the previous conclusions, the two sub basins produce 13,65% of TSS and 17,74% of BOD5 produced by in all sub basins. These parameters are characteristic of the effluents from olive oil mills.
Point source pollution of urban origin although having less expression in water quality is also an important factor in the deterioration of its quality. These two sub basins together produce a considerable amount of pollutant load of urban origin in comparison with the total load produced in the Portuguese Guadiana basin. Quantitatively they produce 8,73 % of COD, 10,64% of BOD 5, 7,67% of total nitrogen and 7,79% of total phosphorus with urban origin produced in all sub basins.
Concerning diffuse pollution, that is that occurring from agriculture and animal production activities run off, these two sub basins, as well as all sub basins located in the Guadiana basin north have a major role in the river water quality. Regarding agriculture activities it is estimated that the annual nitrogen and phosphorus produced loads are in the range of 3000 5000t/year and 200 300 t/year respectively. These values are above the sub basins average. Looking at the run offs from animal production activities the scenario is identical.
The nitrites and oils and fats values in this station are substantially higher than those of other stations used in this analysis. The registered nitrites values may be explained by the low flow found in these sub basins that, together with high temperatures promote the nitrification process. Regarding the oils and fats values it is believed that those may be due to the animal production and slaughterhouses present in the sub basins.
Monte da Vinha
This station is particularly interesting in this analysis because it is located in the border of the countries at the junction of Caia and Guadiana rivers and through it is possible to estimate the pollution load arriving from Spain. This station includes beside the A 3 and A 4 sub basins of the previous station the A 5, and A 1 and A 2 accounted, as referred, with the pollution load from Guadiana River coming from Spain.
The pollutant concentrations are generally higher than those of the previous station with the exception of oils and fats and nitrites that are much lower. This may due to the increase of the river flow that promote a higher oxygenation of the water body, increasing the dissolution of oils and fats and making difficult
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the nitrification processes therefore diminishing the concentration of these two parameters.
The higher values is due not only to the fact that when entering Portuguese territory the river is already polluted but also to the characteristics of the A 5 sub basin that presents, similarly to the previous ones, high pollutant loads. Again, the olive oil refineries, animal production and agricultures are the main point and diffuse pollutant sources.
Therefore the point pollution with industrial origin produced so far in the
Guadiana river Portuguese basin, that is, in the A 3, A 4 and A 5 sub basins will suffer an increase due to those activities. As example we refer the presence of 7 olive oil refineries and 4 piggeries in the A5 sub basin, all connected to wastewater systems. The pollutant loads in these 3 sub basins are 15,61% of the TSS and 18,57% of the BOD 5 produced in all sub basins
The point pollution with urban origin also increases even more significantly than in the case of the industrial sources. If the two sub basins already produced a considerable amount of pollutant load with urban origin relatively to the basin total produced load, the three together produce even more. Quantitatively
14,26% of the COD, 16,17% of the BOD 5, 13,86% of total nitrogen and 14,28% of total phosphorus produced in all sub basins, with urban origin, are produced in these three sub basins.
Regarding diffuse source pollution, that is that coming from the run off of agriculture and animal production activities, it has a considerable role in the river water quality. In the case of agriculture activities it is estimated that the total nitrogen and phosphorus annually produced in A5 sub basin is respectively 3000 5000 t/year and 200 300 t/year. Regarding run off from animal production activities, the scenario is identical.
Comparing the average values obtained by the previous two stations, the differences in concentration of the two analysed parameters do not show so large differences as could be expected. However, it should be referred that the Caia reservoir monitoring station is placed at the Caia dam where it is expected that the pollutants largely sediment. This factor is aggravated by the reduced flows registered at the Caia station. Thus only a small part of the pollutant load present at the Caia reservoir will pass the dam and contribute for the degradation of Guadiana river water quality.
Largest part of the pollutant load has origin in the piggeries present at the A5 sub basin and in Spanish territory because the Spanish station immediately upstream, at Benavides, registers, at least until the year 2000, the worst results of water quality in all parameters except BOD5. It is also estimated that the existing piggeries are responsible for the coliphorm biological contamination registered by the station.
During the field visit it was possible to see that the water near this station presents a poor quality, having a brownish colour, large amounts of floating emulsions and bad odour.
Pollution in this area is essentially organic and biological, with higher BOD5, ammonia and coliphorm values than those registered at downstream stations.
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Lucefécit Reservoir
This station is located at the Lucefécit dam reservoir and serves to characterize the pollutant sources included in the A8 sub basin. The pollution problems seen at this reservoir are evident and although is used only for agriculture purposes it also has the same problems with costly treatment processes.
The fish population has also problems and subsists in a random way. The reservoir is polluted and water has poor quality being only potentially adequate for irrigation, cooling and navigation.
The pollution in this reservoir is essentially due to the existing piggeries which are not connected to wastewater systems and to the run off and discharges coming from these piggeries and from agriculture. The contribution of mining activities and its run offs also contributes to the poor water quality. As in previous sub basins, large part of industrial units and existing animal production sites are not connected to existing wastewater networks and discharge directly to the water lines.
From the obtained data we can conclude that this sub basin is one of the main pollutant sources of all basins. Here is produced 10,46% of TSS, 15,50% of total nitrogen, 91,07% of ammoniacal nitrogen, 72,46% of oils and greases, 100,00% of potassium, 18,79% of faecal coliphorm and 18,78% of total coliphorm produced in all sub basins.
Point source pollution of urban origin, although not as relevant as that from industry and animal production, has values that are in the range of those produced in all sub basins. Here it is produced 2,36% of COD, 2,35% of BOD 5, 3,77% of total nitrogen and 3,90% of total phosphorus produced in all the Guadiana basin located in Portuguese territory.
Regarding diffuse origin pollution, that coming from agriculture and animal production activities runoff, it also has an important role in the reservoir water quality and consequently in the Guadiana river. Concerning agriculture activities it is estimated that the nitrogen and phosphorus annual loads will be respectively 3000 5000 t/year and 200 300 t/year. These values are above the average of all sub basins. Regarding run off from animal production activities, the scenario is identical.
The Lucefécit reservoir is one of the main problems regarding water quality. The main causes are once again the presence of piggeries which are not connected to an adequate treatment system and the run off from agriculture due to bad agricultural practices.
Monte Novo Reservoir
This station is located at the Monte Novo dam reservoir and serves to characterise the pollutant sources included in the B 1 and B 2 sub basins. The pollution problems in this reservoir are evident which is aggravated by the fact that water is abstracted for human consumption. The water in this reservoir needs physical, chemical and disinfection treatment before being inserted in the public supply network. This problem therefore affects not only the sub basins at a public health level but also at an economical level because the treatment process is costly.
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Water abstraction for agriculture use also exists. The water is not fit both for irrigation and fish cultures according to legal standards.
However the water quality has been improving considerably in the last years namely after entering in force of legislation regarding wastewater discharges. Until the 1999/2000 hydrological year the reservoir was classified as very polluted and only partly fit for irrigation, cooling and navigation. The reservoir was classified as hypertrophic.
The water quality has been improving since the 2000/2001 hydrological year but it is still away from being of good quality. The water is still being classified as polluted having acceptable quality for irrigation, industrial use and production of potable water after rigorous treatment. The reservoir is classified as eutrophic.
The pollution in this reservoir is essentially due to animal production activities, piggeries and bovine breeding, which are not connected to wastewater collection systems. Agriculture run off is also an important factor in these sub basins water quality. The remaining industrial activities in the area are not connected to wastewater collection systems discharging their effluents in the water lines.
However these activities produce a much lower pollutant load when compared with the remaining basins. The point source pollution of industrial origin produced in these sub basins, including the animal production activities, has little expression in relation to the total of the Guadiana basin located in Portuguese territory. Urban point source pollution also has a small impact in the water quality. The same cannot be said regarding the diffuse source pollution, that is, that coming from agriculture and animal production activities run off. These two basins play a considerable role in the river water quality. It is estimated that the annual load of nitrogen and phosphorus due to agriculture activities will be respectively 5000 10000 t/year and 200 300 t/year in B 1 basin and 5000 10000 t/year and 100 200 t/year in B 2 basin. The scenario is identical regarding run off from animal breeding activities.
Vigia Reservoir
This station is located at Vigia reservoir and served to characterize the pollution sources included in B 3 sub basin. The pollution problems in this reservoir are evident which is aggravated by the fact that water is abstracted for human consumption. The water in this reservoir needs physical, chemical and disinfection treatment before being inserted in the public supply network. This problem therefore affects not only the sub basins at a public health level but also at an economical level because the treatment process is costly.
Water abstraction for agriculture use also exists. The water is not fit both for irrigation and fish cultures according to legal standards.
The reservoir water quality had some oscillations and has been improving in the last years with the exception of the 2000/2001 hydrological year where the quality has diminished. Between 1996 and 2000 the reservoir was classified as polluted and was classified as being hypertrophic.
In the 2000 2001 hydrological year the water quality worsened and the reservoir was then classified as very polluted. Under those conditions the water as only potentially apt for irrigation, cooling and navigation. The reservoir was classified
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as being eutrophic. However since that year the quality has been significantly improving.
The pollution at this reservoir is due essentially to animal production activities that are largely not connected to wastewater collection systems. Agriculture run off is also an important factor in this sub basin water quality. Regarding the remaining industrial activities most of them are not connected to sewage systems. From the obtained results we can conclude that this is not an important pollution source in the Guadiana basin. We cannot say the same regarding the point source urban pollution.
Regarding diffuse source pollution that comes from agriculture and animal production activities, the values are close to the average pollutant loads produced by the sub basins. It is estimated that the annual load of produced nitrogen is 2000 3000 t/year and produced phosphorus is 100 200 t/year.
Azenha de Cerieiros
The Azenha de Cerieiros station is located in the reservoir of the Alqueva dam and was chosen for being the oldest station in the region. It served to monitor the water quality in this reservoir as well as the contributions of sub basins A and B to the river quality.
This station is also important because it is located at a point of junction of the water lines where all previous stations are located. Thus it is important to verify the increase in pollutant load registered between the referred stations and this pone located in the Alqueva reservoir which is expected to be the convergence point of the pollutant loads.
Comparing the values obtained in this station with the ones of previous stations we see that they are as expected generally higher then those stations in Monte Novo, Vigia and Lucefécit reservoirs. We should note that there are inflows from Spanish territory to this reservoir and therefore part of this pollutant load has its origin in the Spanish part of the basin.
The same cannot be said regarding the Monte da Vinha station. As said before we visited these places in order to determine the explanation to this fact. Although it was not possible to determine that explanation we verified a decrease in water quality close to the Monte da Vinha station where predominates a brownish colour. In the Alqueva reservoir the water colour is somewhat greenish characteristic of eutrophication processes, being possible the starting of an algae bloom.
The existing pollution in sub basins A and B is generally essentially due to the olive oil refineries and agriculture and animal production activities. Besides being the activities that produce more pollutant load they are also the ones that exist in larger numbers in the two sub basins, most of them not connected to wastewater collection systems. Quantitatively there are 70 olive oil refineries of which only 18 are connected to wastewater systems, 175 piggeries of which only one is connected and 50 cattle breeders of which only one is connected and 5 chicken farms none of which is connected.
Regarding point sources we can see that most pollutant load of industrial origin is produced in these two sub basins. With the exception of the COD and total phosphorus, the percentage of pollutant loads produced is higher then 50%
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reaching in some cases 90 or 100% as are the cases of potassium with 100%, ammoniacal nitrogen with 96,92%, organic matter with 90,32% and oils and greases with 88,41%.
The same occurs in relation to the pollutant loads from urban sources. More than 50% of the pollutant load produced in the Guadiana basin located in Portuguese territory has origin in these two sub basins. However the difference is not as high as in the case of industrial sources, not higher than in any case the 60% of production (54,69% of COD, 54,72% of BOD 5, 56,80% of total nitrogen and 58,44% of total phosphorus).
The diffuse sources problem is also worrying in these two sub basins. Despite the aquifers contamination being a slow process in this part of the country, due to meteorological conditions and terrain morphology, most basins are classified as highly pollutant. The most pollutant sub basins are located in the northern part of the Guadiana basin, the pollutant load diminishes as we travel south and the river nears its estuary. Regarding, as an example, the annual nitrogen load produced in the irrigated areas, we highlight the A3, A 4, A 5, A 6, A 8, A 9, B 4 e B 8 sub basins with an annual production higher than 3000 tons. On the other side only 4 sub basins, A 1, B 12 , B 14 and B 16 have phosphorus annual production lower than 500 tons.
The situation regarding phosphorus is similar and the sub basins located further north are the most pollutant with 15 out of 25 sub basins having an estimated annual production higher than 200 tonnes.
Concerning run off from animal production activities only 8 out of the 25 sub basins are classified below class 3. The remaining sub basins are classified as very polluted with 6 of them of class 5.
Lastly we refer the urban sources where the situation once again is repeated. Only 8 out of the 25 sub basins have a classification lower than 3, with 3 being classified as class 5, 7 as class 4 and 7 as class 3.
Rocha da Galé and Rocha da Nora
These stations were chosen to quantify the pollutant load in Portuguese territory downstream the Alqueva reservoir, close to the Pulo do Lobo section that defines sub basin C. Because the Pulo do Lobo station is quite recent we chose these two stations. The Rocha da Galé station ceased activity in 1996 and therefore we chose the Rocha da Nora station to verify the evolution of values since then. There are no junctions between these two stations so we can make a global analysis of them.
Comparing the Rocha da Galé station values with those from the previous station of Azenha de Cerieiros, we observe that the parameters slightly decrease with the exception of total phosphorus, total phosphate, oils and greases and dissolved oxygen. This decrease in pollutant loads may be due to the increase of river flow in this area that promotes a better oxygenation of the water body, causing the degradation and decrease of the values of studied parameters. This fact mat be proved by the increase in dissolved oxygen.
Regarding Rocha da Nora station there is a slight decrease of the pollutant loads with the exception of coliphorm, nitrates and nitrites which suggests biological contamination of the site. This contamination may be originated at the two agro
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food industrial units located in the area the only possible sources of biological contamination.
Regarding the remaining values there is a continuous decrease along the river also decreasing between these two stations.
Pollution in this area is then due to the accumulation of A, B, and C sub basins together with part of D 2 sub basin, where these two stations are located. As referred previously in the analysis of the previous stations the pollution at this area is mainly due to the olive oil refineries and animal production activities that are the main observed activities. There are a total of 215 piggeries and 57 cattle breeders in A, B and C areas all discharging their effluents directly to the water line.
At industrial level and in relation to sub basins included in area C, we must highlight C 1, C 4, and C 8 as they correspond to the sub basins with highest pollutant load production. Sub basins C 1 and C 8 produce respectively 10,58% and 17,10% of total suspended solids produced in all Portuguese basin.
Regarding COD and BOD 5 sub basin C 8 with 15,22% and 18,25% production respectively is the only one that detaches. The BOD5 production in this sub basin is the highest in all Portuguese Guadiana basin. Total phosphorus also reaches the maximum production level in this area of the basin namely in the C 1 and C 4 sub basins with productions of 20,70% and 13,06% respectively relative to the produced total. Regarding total nitrogen only sub basin A8 has a value higher than that in these two sub basins, with productions of 11,30% in C 1 and 12,17% in C 4. The production of total and faecal coliphorm in this last sub basin, 18,88% of the basin total, is worse highlighting.
Regarding pollutant loads with urban origin maximum production is also verified in C 4 sub basin. This sub basin produces 11,12% of COD, 11,12% of BOD 5, 9,96% of total nitrogen and 9,74% of total phosphorus produced in all basin.
Important urban settlements namely the city of Beja is located in this sub basin. The population density is higher than in the remaining Guadiana basin area and because the wastewater treatment is not significantly better than in the remaining sub basins the pollutant load is also higher.
By observing the maps corresponding to diffuse pollution generated in the sub basins we can see that significant pollutant loads are also produced in this area.
In the case of nitrogen coming from irrigated areas sub basins C 1, C 4 and C 10 detach from the others with productions above 10000 tonnes per year. In the case of phosphorus, sub basins C 3 and C7 with productions above 200 tonnes per year are the ones that detach from the remaining. Regarding run off from animal production activities, sub basin C 3 detaches as it is classified as class 5 followed by C 2, C 5, C 7, C 10 and D 2 sub basins of class 4.
Lastly we refer the run off from urban areas which highest production is verified in C 1 and C 3 class 5 sub basins. C 4, C 5 and C 10 .sub basins belong to class 4.
Cais de Alcoutim
This station is located near the city of Alcoutim and corresponds to the upstream chosen station. This selection was made because it is the last station located in the river bed. Apart from this, by observing the data from the remaining stations located further south, mostly in reservoirs, we note that besides being vey
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recent and the number of data reduced there are not significant water quality problems. Therefore this station was chosen preferably to the others.
Comparing this station with the previous one, we see that the studied parameters concentrations little change. Little upstream this station we find the Chanza dam from where flows a significant amount of water coming from Spain. We can conclude that there are no significant pollutant discharges in Portuguese territory and that the pollution coming from Spain significantly affects the water quality.
This no change in values coincides with the almost abrupt disappearing of animal production activities that as already seen contributes a lot to the degradation of water quality.
Agro food industries including dairies and some mining explorations predominate in this area of the sub basin. This predominance may also be observed by the analysis of concentration values that slightly increase. Faecal and total coliphorms have a slight increase due to the dairy industries. COD and total suspended solids also increase due to the agro food industries and mining explorations. The Neves Corvo mines previously referred discharge their pollutant loads between this and previous stations.
Regarding the production of pollutant loads there is not much to detach in these sub basins from the remaining ones. At point level only the production of COD with industrial origin in sub basin D 1 which reaches the higher value of all sub basins is to highlight. This may be due to the location of the Neves Corvo mines in this sub basin.
Regarding point pollution with urban origin pollutant loads produced in these sub basins are below the average verified in all sub basins.
Analysing the diffuse pollution maps we note that this also significantly decreases in this final area of the basin. Pollutant loads here produced are much lower than those produced in the sub basins located further north.
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5 Conclusion The needs to satisfy the basic requirements of water must be accompanied by the availability of water of enough quality for its use for human consumption and irrigation. The increase of water demand and the inadequacy of water management in the agricultural, industrial and domestic sectors, together with the consequences of the climatic conditions in the river regime, contribute to the decreased availability of adequate water quality. In semi arid regions the availability of surface water in wet periods is worsened by the increase of pollution load and water temperature. The decrease of the river flow leads to loss of water quality from less dilution of partially polluted water. The main sources of pollution in the Guadiana basin are untreated discharges, especially from industries and diffuse pollution, originating from agriculture and cattle, without any treatment both in Portugal and Spain. In intensive agriculture zones, the aquifers have a high nitrate pollution risk. On the Spanish side, the Guadiana middle basin, many municipalities have high industrial areas, largely meat industries and olive oil manufacturing. The lack of purification is clearly reflected in the quality of the water in the receiving channels. Also cattle’s breeding affects the water quality in aquifers. These waters contain high quantities of organics and phosphates. In the lower part of the basin, industrial untreated spills influence the water quality. Meat industries and olive oil mills, and also mining operations, are the major causes, directly or indirectly, bad water quality. On the Portuguese side, food industries (olive oil), leather industries, manufacturing of transport material, solid waste, manufacturing of metallic products, wood and the cork oak industry, manufacturing of machines and equipment, and rubber manufacturing are important sources for water pollution. Also, non controlled municipal solid waste depositories are important sources for environmental problems. Besides the obvious need of a sufficient quantity of water there are serious concerns related to the water quality in the reservoirs. The main problems that may affect this quality are: eutrophication caused by the discharge of nutrients, silting caused by accumulation of low size inorganic material, and salinisation when evaporation exceeds precipitation. These polluting processes cause serious constraints in the utilisation of water for irrigation and human consumption. If we stopped polluting the Alqueva now it would take around five years to improve the situation in terms of water quality. This has consequences for the high quality tourism projects that are planned for the region. The analytical study of water quality and its relation with the pollution that occurs in the Guadiana hydrographical basin is particularly difficult because it results from a large set of factors that overlap without existing one that by its importance conditions the system characteristics. We can say that due to its density in the region and the produced pollutant loads, that the olive oil refineries and animal production activities, and agriculture activities, are those that most contribute to worsen the Guadiana river water quality.
However if we add the hydrometrical and meteorological parameters, as temperatures and the large irregularity of rainfall distribution, we conclude that these also highly condition the water quality in the Guadiana basin.
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The “pollutant agents” may be, in a very schematic way, classified in three large groups:
• one in which the loads arrive continuously, with an almost uniform flow independently of run off, as is the case of urban wastewaters, • one in which the loads arrive seasonally and independently of run offs, as is the case of olive oil refineries effluents, and • another one in which the loads arrive when there is generalized run off as is the case of diffuse pollution.
Big investment effort in wastewater treatment infrastructures has been made in the last years by the administrations of both Spain and Portugal. The first political agreements between Portugal and Spain envisaging cooperation in the management of international rivers are from the 1960’s. Although the Albufeira Convention signed in 1998 is a strong advance in the development of cooperation and information between the two countries, a joint management of transboundary river basins like Guadiana is yet to be achieved.
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6 List of references • DSRH – “Metodologias de Avaliação dos Recursos Hídricos Subterrâneos” – INAG, 1998. • Gomes, Fernanda; Rodrigues, Rui – “Modelação Hidrológica Distribuída na Bacia do Rio Guadiana. 4º Congresso da Água”, INAG 1998. • Gomes, Fernanda; Rodrigues, Rui – “Modelação Hidrológica Distribuída. Aplicação à Bacia do Guadiana” – INAG. • INAG – “Zonas Sensíveis e Menos Sensíveis” – INAG, 199?. • INAG – “Reconstituição dos Recursos Hídricos Superficiais em Regime Natural. MARN, 1995. • INAG – “Aquíferos Transfronteiriços da Bacia do Guadiana”. DSRH, 2001. • INAG – “Redes de Monitorização de Águas Subterrâneas no Alentejo”. • Ribeiro, Luís; Cortez, Leopoldo; Durão, Fernando; Lopes, Ana R. – “Modelos de Representação Global para Caracterização de Sistemas Aquíferos Cársicos”. • Paralta, Eduardo A.; Francês, Alain P.; Costa, Augusto M.; Sarmento, Paula A.; Ribeiro, Luís Tavares; “Estudos Hidrogeológicos e Redes de Monitorização do Bloco de Rega de Canhestros (Alentejo) no Contexto das Preocupações Agroambientais e da Directiva Quadro da Água”. • Henriques, António G.; West, Cristina A.; Pio, Simone – “Directiva Quadro da Água, Um Instrumento Integrador da Política da Água da União Europeia”. • João, Elsa; Fonseca, Alexandra – “ Environmental & Spatial Analysis – London School of Economics, 1996. • Lencastre, A.; Franco, F.M. – “Lições de Hidrologia” – UNL, 1984. • Linsley, Ray K. – “Water resources Engineering”, MacGraw Hill. • Directiva 2000/60/CE Do Parlamento Europeu e do Conselho de 23 de Outubro de 2000. • Decreto Lei 236/98, de 1 de Agosto. • Plano de Bacia Hidrográfica do Rio Guadiana, INAG, 1998. • Aplicação da Directiva Quadro da Água e Convenção Luso Espanhola de 1998 na Bacia Hidrográfica do Guadiana, Euronatura, 2003. • Projecto IBERAQUA Workshop sobre a Bacia do Guadiana, Relatório Final – Euronatura, 2002. • Kinkead, J.; Hilkene, C.; Dennis, P. A Review of Watershed Management Experience BEAK INTERNATIONAL INCORPORATED, 2001. • Icep PERFIL SECTORIAL Agricultura e Indústrias Agro alimentares, Icep 2000. • Convenção sobre Cooperação para a Protecção e o Aproveitamento Sustentável das Águas das Bacias Hidrográficas Luso espanholas. • Gooch, Geoffrey D.; Höglund, Pär; Gulnara Roll; Lopman, Evelin; Aliakseyeva, Natallia; “Review of Existing Structures, Models and Practices for Transboundary Water Management”, Mantra East, 2002.
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• INAG – Estado de Aplicação em Portugal das Directivas Comunitárias em Relação à Água, INAG, 2002. • Rodrigues, Rui; Brandão, Claúdia; Hydrological Simulation of International Catchments of Guadiana River – INAG, 2000.
b) Websites
• www.inag.pt • http://snirh.pt/ • www.iambiente.pt • www.ltid.inpe.br/dsr/vianei/CursoHF/capitulo7c.htm • www.meioambiente.pro.br/agua/guia/ocorrencia.htm • www.meioambiente.pro.br/agua/guia/poluicao.htm • www.edia.pt • www.ifadap.min agricultura.pt • www.qca.pt • www.agroportal.pt
59 List of references
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