DSS application at a river basin scale, taking into account water resources exploitation risks and associated costs: The Algarve Region

Presented at the conference on Water Resources Management: New Approaches and Technologies, 14–16 June 2007,Chania, Greece.

0011-9164/09/$– See front matter © 2009 Elsevier B.V.

Desalination 237 (2009) 81–91

DSS application at a river basin scale, taking into account waterresources exploitation risks and associated costs:

The Algarve Region

Rodrigo Maia*, Cristina SilvaDepartment of Civil Engineering, Faculty of Engineering of the Univeristy of Porto, Portugal

Tel. +351 (22) 508-1916; Fax: +351 (22) 508-1955; email: [email protected]

Received 18 August 2007; Accepted 2 December 2007

Abstract

The increase on water demand of the different sectors lately so commonly verified, namely for domestic use, hasbeen a major incentive towards the development and use of Decision Support Systems (DSS). In the context of aEuropean Project, a DSS tool was developed and applied to the Algarve region, in Portugal, having as major purposethe sustainable management of the water resources existing in the whole region. Different strategies (combinationsof water management options) were defined and evaluated using the DSS tool aiming at minimizing the existing andforeseen water deficits in the region having in mind the requirements specified by the Water Framework Directive(WFD). A performance assessment of strategies and an economic analysis embracing direct and environmental costscomputed by the tool do enable selection of strategies. The results of the evaluation of two strategies to minimizeregional ground and surface water resources exploitation risks and costs are presented. The specific case of theQuerença-Silves aquifer’s exploitation is addressed, as it is the most important (in quantity, quality and pressuresdue to current and potential future use) of the Algarve region.

Keywords: Decision support system; Environmental costs; Querença-Silves aquifer

1. Introduction

The Algarve region, the southern region ofPortugal, which embraces the Ribeiras do

*Corresponding author.

Algarve river basin and also a small part of theGuadiana river basin, benefits from favourableweather conditions. In this region, the increase inwater demand mostly from agricultural anddomestic sectors has been, for almost two de-cades, one of the main problems for the balanced

Published by doi:10.1016/j.desal.2007. .012 24

R. Maia, C. Silva / Desalination 237 (2009) 81–9182

economic and tourist development, as that in-crease has not always been compatible with theexisting water resources. Until the 1990s, domes-tic water supply in the region was almostexclusively relying on municipal boreholes.Additionally, agriculture and industry were alsousing the existing groundwater resources whichled to a severe decrease in the piezometric levelsand to quality problems in the majority of theaquifers, mostly those in the coastal zones [1].These coastal aquifers have also current increas-ing water exploitations pressures due to touristinvestments (namely on new golf courses) in theregion. Conflicts between the different waterusers and agriculture (representing more than65% of the total water consumption volume) dothen exist in the region.

In that context, in the late 1990s, decisionmakers agreed on the need to improve domesticwater supply at regional level, in terms of waterquality, water quantity and also efficiency ofassociated water services. The proposed solutionwas to implement two primary inter-municipalwater supply systems (one for the eastern part ofthe region and the other for the western part),both based on surface water sources, whichwould assure the conveyance of treated waterfrom the storage supply reservoir sources to themunicipal reservoirs. The municipalities wouldthen be only responsible for the operation andmanagement of the secondary water supplysystems, i.e. from the municipal reservoirs to thedifferent settlements (and end-users), and wouldabandon their former (own) groundwater abstrac-ions. The two primary water supply systems werethen interconnected, creating the primary watersupply system as known today, operated by asingle water utility: the Águas do Algarve, S.A.(AdA). This company is then responsible forsupplying treated water to (most of) the differentmunicipalities of the region. This primary supplysystem is depending on the main storagereservoirs existing in the region (Fig. 1), corre-

sponding to the Bravura, Arade and Funchodams, also used for agriculture, to supply thewestern part; and, the Odeleite-Beliche damssystem (located in the Guadiana river basin), tosupply the eastern part. Although based on threestorage reservoirs, the water availability in thewestern part of the region is lower than in theeastern one as those storage reservoirs’ capacityis reduced. In fact, according to the plannedprimary water supply system design a new watersource (Odelouca dam, storage capacity 157 hm3)would also be built to supply the western part.Regrettably, the scheduled plan (start of operationin 2006) could not be fulfilled and the con-struction was put at risk due to environmentalissues; in fact, the decision to go on with the damconstruction was (re)confirmed recently (end of2006), making the (before expected) start ofoperation in 2012 possible.

Meanwhile, AdA company faced some diffi-culties in fulfilling the increasing water demand,as this was reaching values clearly above the onesexpected in planned demand scenarios. Adding tothat, a dry period verified between 2003 and 2005originated a severe decrease in water availabilityin the different storage reservoirs and conse-quently strongly limited the water abstractions fordomestic water supply. This situation led to thenecessity of finding alternatives on a very shortterm to guarantee public water supply to theregion in good quantitative and qualitative terms:the executable solution, found jointly with thedifferent municipalities, was to re-activate (asemergency supply sources) some municipal bore-holes formerly abandoned due to the implemen-tation of the primary water supply system,allowing mitigating the water shortages ori-ginated by the dry period. Additionally to thisaction, AdA, with the previous agreement of theNational Water Institute (INAG), equipped andstarted exploiting some new boreholes, located inthe western part of the most important aquifer ofthe Algarve region, the Querença-Silves aquifer

R. Maia, C. Silva / Desalination 237 (2009) 81–91 83

Fig. 1. Primary water supply system and water supply sources of the Algarve region.

(see Fig. 1). These boreholes were executed forirrigation purposes but were by then still notbeing used.

The shortage situation revealed, once more,the imperativeness of considering more severehydrological scenarios in the planning andmanagement of existing water resources. It alsoled to the necessity of urgently defining a firstversion of a contingency plan for public watersupply in drought situations. This contingencyplan considered then different scenarios and dif-ferent planned actions, namely the above referredre-activation of the former municipal boreholes,when situations of important limitations in sur-face water abstraction volumes might occur. Inthat context, FEUP (Faculdade de Engenharia daUniversidade do Porto) was by then requested byAdA to simulate the management risk of exploit-ing the Querença-Silves aquifer under differentwater availability conditions, using the DSS tooldeveloped under the WaterStrategyMan Project(of the 5th EU Framework Programme) in which

AdA collaborated also as regional stakeholder[2].

The paper presents some of the work devel-oped and the results obtained on that scope, morespecifically regarding two strategies definedaccording to AdA’s interests and foreseeninvestments.

2. WSM–DSS tool

The main functions of the WSM–DSS toolwere framed taking into account the drivingforces–pressures–state–impacts–responses(DPSIR) conceptual framework as defined byWalmsley [3] and also used by the EuropeanEnvironmental Agency (EAA). The modellingapproach used relies on Geographical InformationSystems (GIS) capabilities and on adapted data-bases. Five main modules form the main core ofthe program:C the water availability module which estimates

the available water resources in aquifers or


reservoirs through the generation of monthlytime series of corresponding inflows (aquifersrecharge and run-off),

C the water demand module which generateshypothetical demand scenarios for the differ-ent kinds of water users and respective growthrates considered,

C the allocation module which is responsible forthe simulation of the water distribution withinthe network from the supply nodes to thedemand nodes according to pre-definedpriorities,

C the water quality module which estimates theevolution of selected water quality parametersunder the specific water demand, water avail-ability and allocation priorities,

C the economic analysis module which is anattempt of implementing the principles ofcost-recovery emerging from the WaterFramework Directive [4] (based on the assess-ment of direct, environmental and resourcecosts), and finally,

C the evaluation module which facilitates thecomparison of the different strategiesdeveloped.

The WSM–DSS tool allows the user toanalyse the water system behaviour, according toexisting or expected regional hydrological anddemand scenarios and analyse the impact of the(sole) implementation of different kinds of watermanagement options in the system’s perfor-mance over a simulation period up to 50 years.Additionally, different water management optionscan be spatial and temporally combined, definingstrategies which performance can be evaluated.These strategies can also be refined through theconsideration of a cost recovery scheme intendingto achieve pre-defined targets in terms of costrecovery levels for direct, environmental andresource costs. This re-evaluation of the strategiesenlarges the spectrum of the analysis andcomparison to be performed as the user is able tocompare strategies in terms of efficiency in

reducing water stress but also in mitigating envi-ronmental constraints and achieving economicsustainability [5].

3. Querença-Silves aquifer management ex-ploitation risk

3.1. Considerations and scenarios

Although the simulations performed using theWSM–DSS tool are generally developed at theregional scale, the obtained results can also bediscriminated more locally, namely for eachspecific water source. In this specific study, asgroundwater resources, and more specifically theQuerença-Silves (QS) aquifer, are consideredstrategic water sources, special attention wasgiven to the results obtained in that particularaquifer.

In a first set of simulations, it was assumedthat the existing water deficits for urban usewould be solved only by increasing waterabstractions in the QS aquifer. The scenarioconsidered in the analysis corresponds to com-bining an availability scenario that repeats thehydrological sequence verified in the last 35years (“Normal” scenario) and a demand scenariobased on the current trends of the region (“BAU”,business-as-usual scenario), as defined in theRiver Basin Plan [6]. This scenario will be re-ferred to as the BAU+Normal scenario. More-over, in order to perform these simulations,according to the description made in Section 1and considering the current operation of theprimary water supply system, some limitationshad to be considered concerning the real volumeavailable for abstraction in the existing surfacewater sources of the region as well as in thepumping station allowing to transfer water fromthe eastern to the western part of the system (andvice-versa). More specifically, and in accordancewith AdA, it was considered that: (1) at theFuncho storage reservoir, the maximum volumeavailable for abstraction for domestic water


Fig. 2. Evolution of the GEI of the Querença-Silves aquifer, considered as the major alternative water source, for theBAU+Normal scenario and considering an annual recharge volume of: (a) 86 hm3; (b) 70 hm3.

supply purposes was: 12 hm3 in dry and very dryyears, 17 hm3 in normal years and 23 hm3 in wetand very wet years; (2) at the Bravura storagereservoir, a maximum water abstraction of 4 hm3

per year was possible; and (3) the pumpingstation would transfer 7 hm3 per year until 2010.This volume would be then reduced by 0.5 hm3

every 5 years until 2030.Considering that set of limitations, special

attention was given to the Querença-Silvesaquifer as it would be the alternative supplysource. It was assumed that only 80% of therecharge of this aquifer should be used, trying toprevent depletion of the aquifer and consequential

quantity and quality problems that could be notreversible. The analysis considered two possiblevalues (70 hm3 and 86 hm3) for the averageannual recharge volume of the QS aquifer, inorder to take into account the range of limits ofvalues of different accepted existing scientificstudies on that aquifer [7].

3.2. Querença-Silves exploitation index evolution

The results hereafter presented correspondspecifically to the evolution of the groundwaterexploitation index (GEI), ratio between abstrac-tions and recharge of the Querença-Silves aquifer,


considering that no limitation in water abstractionfrom this aquifer was imposed for public watersupply purposes. These results are compared withthe so-called “reference case” that represents thesimulation of the 35-year period without theintroduction of any kind of water resourcesmanagement options in the water system (and so,with no additional water abstractions for domesticpurposes from the aquifer in addition to theexisting ones at the beginning of the simulationperiod). Fig. 2(a) and (b) show the GEI resultsover the simulation period respectively for eachof the two different values for annual rechargeconsidered (70 hm3 and 86 hm3).

If the average GEI index value over thesimulation period is considered, it can be verifiedthat: (1) for the 86 hm3 annual recharge volume(Fig. 2a), the average GEI value is 62% and 82%for the reference case and for the case of addi-tional abstractions in the Querença-Silves aquifer,respectively; (2) for the 70 hm3 recharge value(Fig. 2b), the corresponding GEI reaches 76% forthe reference case and more than 100% whengroundwater abstractions over the simulationperiod are intensified. However, if only the last15 years of the analysis period are considered, theGEI is almost always above 100%, in both situ-ations, with increasing amplitude of the higherpeaks, reaching values above 150%, and even200% for the lowest value of recharge (Fig. 2b).Having that in mind and aiming at the sustainablemanagement of water resources, it seemed rea-sonable to assume that using the Querença-Silvesaquifer as an alternative water source for publicwater supply could be a potential solution onlyuntil 2015 or 2012, respectively if 86 hm3 or70 hm3 of annual recharge are considered.

These results were unfortunately confirmed bythe decrease observed in the piezometric levels ofthe Querença-Silves aquifer during the 2003–2005 period, leading to serious danger of theaquifer’s salinization, even with limited volumesof water abstracted from it, revealing that thismeasure cannot be considered, in an isolated way,

as a medium or long-term solution. Moreover, theother aquifers existing in the region are still suf-fering the consequences of the overexploitationverified until the 1990s regarding quantity andquality aspects, which lead to strong limitationson water abstractions from those water sourcesimposed by water authorities. That way, thedifferent institutions involved in regional waterresources management, and particularly AdA, hadto consider other alternative options for the miti-gation of water deficits.

4. Strategies formulation and analysis

4.1. Formulation of the strategies

The considerations made for the QS aquiferwere taken into account in some of the strategiesdefined in accordance with AdA, namely in thetwo specific strategies presented by Maia andSchumann [5]. These two strategies for mitigatingthe foreseen water deficits on a 35-year periodwere an attempt of considering two differentapproaches for solving the water deficits thatcould be expected when considering two differentglobal scenarios: (1) the BAU+Normal scenario,described before (in 3.1); and (2) the BAU+HDscenario, which is a hypothetical more severeavailability scenario characterised by a high fre-quency of dry years (HD), resulting from theconsideration of a 10% reduction of the averageannual precipitation values used in the Normalscenario, combined with the same demand (BAU)scenario as in (1).

Summarily, the two defined strategies can bereferred as:C Strategy 1: a combination of the exploitation

of surface water sources (considering theimplementation of the Odelouca dam) and theintroduction of other measures like pipe waterlosses reduction, representing the current mostcommon (i.e., structural) solutions, as definedin the River Basin Plan.


C Strategy 2: a tentative approach to emphasizethe interest of non-structural water manage-ment options [8], preferably at the local scale,like water re-use, as well as alternative optionslike desalination plants (reverse osmosis) thatare not common solutions in the region. Thetwo desalination plants considered aimed atsolving local water shortages in two differentmunicipalities, originated in the first case byquality problems and in the other by quantityissues. Their treatment capacities were set inorder to overcome the expected water deficitin the last year of the simulation period. Moreimportantly, this strategy intended to focus onthe sustainable use of surface and groundwaterin order to preserve water resources.

As mentioned before, the sustainable use ofthe Querença-Silves aquifer was also taken intoaccount in the formulation of the strategiesthrough the limitation of the volume to be ab-stracted from the aquifer. That way, in strategy 1,the potential intensification of Querença-Silveswater abstractions only takes place until 2012when the Odelouca dam is expected to startoperating, while in strategy 2, an additional (butlimited) potential water abstraction volume fromQS is maintained until the end of the simulationperiod.

4.2. Evaluation of strategies concerningeffectiveness

For the comparison of the strategies, the userhas to select the most relevant indicator(s) for theanalysis to be performed, which can be divided inthree main categories: “resources and environ-ment”, “efficiency” and “economics”. Also therange for which the values of the chosen indi-cators are considered satisfactory has to bespecified. The assignment of a relative weight toeach chosen indicator allows the WSM-DSS toolto compute the so-called Relative PerformanceIndex, which translates the sustainability of the

Table 1Evaluation of strategies regarding effectiveness (RPI)

Referencecase

Strategy1

Strategy2

BAU+Normalscenario

0.300 0.572 0.638

BAU+HD scenario 0.300 0.566 0.668

system, over the simulation period, according tothe importance given to each indicator [5].Having in mind the emphasis given to domesticwater supply, the selected indicators were: thedomestic demand coverage (percentage of supplyover demand, weight 0.4), the irrigation demandcoverage (idem, for agriculture, weight 0.3) andthe groundwater exploitation index (percentage ofabstractions over recharge, weight 0.3). Table 1presents the results obtained considering theeffectiveness (Relative Performance Index, RPI,for demand coverage) of the two strategiesanalysed and of the reference case (as defined in3.2.), under the two global scenarios described.

Table 1 shows that, under the two scenarios ofanalysis, and considering the three chosen indi-cators, strategy 2 achieves a better effectivenessthan strategy 1. The economical comparison willbe presented below (see Section 5.3).

4.3. Querença-Silves exploitation index evolution

The strategies defined and briefly explained inSection 4.1 represent the global intervention atthe regional level. The consequences of it at thelocal level and namely, following the study per-formed in Section 3.2, the evolution of the GEI ofthe Querença-Silves aquifer under the two differ-ent scenario conditions and for the two strategiesconsidered (Fig. 3) was also analysed.

This time, in both global scenarios studied,maximum values above 80% with three peaks (inthe last ten years) reaching more than 100% canbe observed. If the averaged GEI values for the


Fig. 3. Evolution of the GEI of the Querença-Silves aquifer for the two different scenarios and management strategies.

entire simulation period are considered, that ave-rage is below 80% for the four different combi-nations analysed with a minimum of 62% forstrategy 1 under BAU+Normal scenario and amaximum of 70% for strategy 2, under BAU+HDscenario, showing that in an inter-annual basis,the satisfactory results of the two strategiesproposed are also influenced by the behaviour ofthe Querença-Silves aquifer. The referred peaksover the last 10 years of the simulation’s periodreach a maximum of 110% but, each time, theaquifer recovers to values below the 80% limit,confirming a sustainable use of the aquifer.

5. Cost analysis

5.1. Importance of the cost analysis

A relevant comparative analysis that can beperformed through the WSM–DSS tool is the

economic analysis. The one presented in thisstudy focus only on direct and environmentalcosts definition and evaluation, which is in linewith the main goals of the WFD.

5.2. Determination of direct and environmentalcosts

5.2.1. Direct costs

In accordance with Maia [1], the direct costsconsidered for the Algarve region have beendefined based on the evaluation of:C Depreciation of capital costs associated to past

and new investments, for both domestic, irri-gation and industrial uses.

C Operation and maintenance costs of new andexisting infrastructures, for domestic, irriga-tion and industrial purposes.All the necessary data for the definition of

direct costs were collected from the different


national and regional institutions, official reportsand the different stakeholders involved.

5.2.2. Environmental costs

The estimation of environmental costs is muchmore difficult than direct costs estimation as theycannot be directly measured and assessed asinvestments for example. The correspondingWSM–DSS chosen approach is in accordancewith EU guidance water economics principles [9],as:C It was considered that all the users should pay

the environmental cost corresponding to theiruse of the natural resource: principle of equity.

C Environmental costs considered the associatedcosts of an alternative structure whose mainpurpose would be to supply the maximumshare of non-sustainable water abstracted inthe existing water sources.

In the application to the Algarve region, theenvironmental costs were estimated consideringthe aspects and limitations explained beforeconcerning the existing water sources. That way,concerning groundwater resources, the examplechosen for that evaluation was the Querença-Silves aquifer due to its dimension and watersupply strategic importance in the region. Aspreviously mentioned, it was assumed reasonableto consider for a “Normal” availability scenariothat approximately 20% of the annual recharge isleft aside to guarantee natural discharges. Havingthat in mind, the groundwater environmental costwas estimated as equal to the construction, opera-tion and maintenance costs of a desalinationplant, designed to guarantee that same volume ofwater. The corresponding estimated value of0.15 €/m3 was applied to every abstraction fromany aquifer located in the Ribeiras do AlgarveRiver Basin.

For surface water abstraction environmentalcosts, the case of Funcho and Arade storage reser-voirs, in the western part of the region, wasanalysed. The combined exploitation of these two

storage reservoirs is not sufficient to satisfydomestic demand needs (for a BAU scenario) bythe end of the simulation period in this part of theregion. In order to fulfil the estimated additionaldemand of 37 hm3 in 2035, an alternative supplysource has to be provided. With that purpose, twoalternative supply sources were considered:(1) construction of a dam with an overall storagecapacity of 48 hm3 (taking into account, namely,evaporation losses); and (2) construction of twodesalination plants with a total capacity of37 hm3. The environmental cost average estimate(of those two alternatives) of 0.10 €/m3 for sur-face water abstractions was considered.

Finally, in what concerns pollution originatedby effluent discharges, environmental costs havebeen set equal to the operating expenses of asecondary wastewater treatment plant (0.20 €/m3).Moreover, a secondary and tertiary treated efflu-ent discharge bonus of 0.20 €/m3 was estimated.

5.3. Evaluation of strategies concerning directand environmental costs

Table 2 presents the cost analysis comparisonof the strategies considered under the twoscenarios of analysis, taking into account theevaluation of direct and environmental costs. Asverified for the effectiveness parameter (Table 1),also in economic terms strategy 2 performs betterthan strategy 1 for the two scenarios, with lowervalues of direct and environmental costs.

6. Evaluation of global strategies and theirrefinement

The evaluation of the two strategies wasperformed by means of the effectiveness (Section4.2) and cost (Section 5.3) assessment, enablingglobal and full comparison (and best choice) ofstrategies. Those strategies could then be refinedthrough the capability, incorporated in the WSM–DSS tool, of a cost recovery assessment aiming at


Table 2Direct and environmental cost estimations for strategies 1 and 2

Present value (M€) Reference case Strategy 1 Strategy 2

BAU+Normal scenario Direct costs 1690 2361 2252Environmental costs 692 700 667

BAU+HD scenario Direct costs 1665 2360 2245Environmental costs 687 699 667

achieving goals as defined in the Water Frame-work Directive [10].

In this case, for that purpose, Maia and Schu-mann [5] determined a differentiated increase(every two years from 2005 to 2015) in waterprices for domestic users in order to achieve100% recovery of direct costs in 2020 and aminimum of 75% of recovery for environmentalcosts by 2025. The results obtained showed thatthe increase would also (logically) be smaller forstrategy 2: 65% against 78% for strategy 1.

7. Conclusions

The WSM–DSS application proved to be aninteresting Decision Support System tool suitedfor the Algarve region water resources analysis.The range of water management options availableto be tested allowed defining strategies that takeinto account not only the specificities of theregion but also the limitations in water sourcesabstractions (defined by regional and nationalstakeholders) in order to promote their sustain-able exploitation. Special attention was given tothe exploitation of the Querença-Silves aquifer,which is the most important and reliable in theregion.

Two defined strategies were compared interms of efficiency and also direct and environ-mental costs. Those were evaluated according toWFD requirements, with environmental costsbeing estimated taking into account the referredanalysis of sustainable exploitation of water

sources. Both strategies proved to enable reachingsatisfactory values of efficiency showing thatoptions like desalination units can be alternativeto be taken into account towards traditionalsupply solutions used in Portugal (as dam con-struction). The Querença-Silves aquifer proved tobe able to recover in terms of water storage on aninter-annual basis.

Nevertheless, it should be emphasised that theresults presented have to be considered as illus-trations of the capabilities of the tool and of theanalysis that can be performed through the WSM-DSS use. The adequate use of the tool requires acareful selection of the indicators and associatedweights, as those obviously influence the effi-ciency results of the strategies defined.

References

[1] R. Maia, in: P. Koundouri, K. Karousakis, P. Jeffrey,D. Assimacopoulos and M Lange, eds., WaterManagement in Arid and Semi-arid Regions: Inter-disciplinary Perspectives, Edward Elgar, Chelten-ham, UK, 2006, pp. 41–104.

[2] C. Silva and R. Maia, Reducing the vulnerability ofsocieties to water related risks at the basin scale,Proc. Third International Symposium on IntegratedWater Resources Management, Germany, IAHSPubl. 317, 2007.

[3] J.J. Walmsley, Environ. Manage., 29(2) (2002) 195–206.

[4] EC Directive, 2000/60/EC of the European Parlia-ment and of the Council Establishing a Frameworkfor Community Action in the Field of Water Policy.


[5] R. Maia and A. Schumann, Water Res. Manage.,21(5) (2007) 897–907.

[6] INAG, Socioeconomic development prospectiveanalysis (in Portuguese). Plano de Bacia Hidrográficadas Ribeiras do Algarve (River Basin Plan of theRibeiras do Algarve River Basin), 2nd phase. Vol. II,Ministério das Cidades, Ordenamento do Territórioe Ambiente, Portugal, 2000.

[7] C. Almeida, J.L. Menclonça, M.R. Jesus and A.J.Gomes, Aquifers of continental Portugal, Instituto daÁgua, Portugal, 2000 (in Portuguese).

[8] P.H. Gleick, Science, 302 (2003) 1524–1528.

[9] WATECO, Common Implementation Strategy forthe Water Framework Directive (2000/60/EC).Guidance Document No 1: Economics and theEnvironment — The Implementation Challenge ofthe Water Framework Directive, Office for OfficialPublications of the European Communities, Luxem-bourg, 2000.

[10] D. Assimacopoulos, Recovery of full cost andpricing of water in the Water Framework Directive.Re-assessment of the Water Resources and Demandof the Island of Cyprus, Cyprus, 2000.

Documents

DSS application at a river basin scale, taking into account water resources exploitation risks and associated costs: The Algarve Region