gis based multicrteria analysis in integration of sea ... · pdf file2 chair of spatial...

Int. J. Environ. Res., 6(4):1053-1066, Autumn 2012ISSN: 1735-6865

Received 19 March 2011; Revised 12 Feb. 2012; Accepted 19 March 2012

*Corresponding author E-mail: [email protected]

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GIS Based Multicrteria Analysis in Integration of SEA Process Into Planning, CaseStudy: South West Region, Republic of Ireland

Vukicevic, J.S.1 and Nedovic-Budic, Z.2

1 Planning and GIS Consultant, Republic of Ireland2 Chair of Spatial Planning and GIS, University College Dublin, Republic of Ireland

ABSTRACT: Strategic Environmental Assessment can be viewed as a process to integrate the concept ofsustainable development into planning. In this context, SEA can be regarded as a method that regulates theplanning process to a state of sustainable development. However, to reach that goal it is necessary to achievefull integration of planning and the SEA process.Therefore this paper considers the integration of SEA into theplanning process based on GIS multicriteria analysis. The paper is an attempt to introduce the concept ofenvironmental protection in the planning process on the principle of dynamic modelling with the aim ofidentifying potential impacts of planned activities on the environment and determining the optimal alternativedevelopment. Moreover, the paper will introduce the model of integration of SEA process into planning as oneapproach to reach the goal of full integration of the two processes and therefore will assist the planner anddecision maker to achieve a more sustainable decision.

Key words: Planning, SEA,GIS, Multi-criteria Analysis, Analytic Hierarchy Process

INTRODUCTIONThe approach in this paper is an integration of the

SEA process into planning through the “integrationmodel”. The integration model represents a set of GIS-oriented multicr iter ia procedures to integrateenvironmental considerations with the planning processin order to reach sustainable development principles.The model consists of two sub-models: cumulativeenvironmental sensitivity sub-model and expecteddevelopment pressures sub-model.

The cumulative environmental sensitivity sub-model can be regarded as evaluation of allgeographically mappable environmental factors thatcould be affected by planned development activities.The development pressure submodel reflectsdevelopment indicators as the main cause of possiblenegative environmental impacts. The cumulativeenvironmental sensitivity submodel is universallyapplicable in all planning systems, but with using thelocal indicators, while the expected developmentpressures sub-model universally is applicable at thestrategic level but not at the local level. Local levelplanning is much more focused on local conditionsand the local planning system, particularly in land use;

therefore this model requires the necessary calibrationaccording to specific local conditions.

According to research of Malczewski(Malczewski, 2006) almost 70% of all published paperson GIS-MCDA have been published in the last fiveyears. That suggests that we can expect increasedapplication of the GIS-MCDA concept in the future.Also, according to stated analysis of the most usedMCDA techniques, the Boolean overlay technique isthe most applicable with nearly 40% of all publishedliterature referring to this technique, while the Analytichierarchy process defined by researchers (Saaty, 1980,2008; Saaty and Ozdemir, 2005; Saaty and Forman 1993)is represented with approximately 10% in publishedGIS-MCDA literature.

On the other hand, Malczewski (Malczewski,2006) found in his research that GIS-MCDA conceptwas used in urban and regional planning in 10% ofpublished papers, while the concept of environmentalprotection (environment / ecology) is the most commonwith 17%.

After analysing the literature about thepossibilities of applying GIS-MCDA in environmental

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Vukicevic, J.S. and Nedovic-Budic, Z.

planning, it can be concluded that in most cases GIS-MCDA is oriented to assessment of impact to onereceptor, like aero pollution (Makowski, 2001). On theother hand, an assessment could be based on onesource of impact, like the construction of new road(Patrono, 1998).Nevertheless, the question is can we employ GIC-MCDA in achieving cumulative environmentalsensitivity of observed area?Gonzales Del Campo (2008, 2009) applied that conceptin the Kilkenny County Development Plan and shehas also suggested this principle in GIS-SEAGuidelines (Gonzales Del Campo, 2008 ). She usedweighted-overlay mapping technique in combinatinwith MCDA and GIS for producing the CumulativeEnvironmental sensitivity map.The main difference between the concepts of GonzalesDel Campo and the approcah for determiningCumulative Environmental Sensitivity map (Cumulativeenvironmental sensitivity submodel) in this paper isthe applied MCDA techniques in indicatorsassessment. In Gonzales Del Campo (Gonzales DelCampo, 2008) methodology, all relevant indicators aregrouped into two groups with an assigned “weight”of 5 and 10 points. A group of indicators which areassigned to 10 points is more important from thestandpoint of the environment.

On the other hand, within the CumulativeEnvironmental sensitivity submodel AnalythicHierarchy Process (AHP) was applied in the indicatorsassessment. Using the AHP, the indicators arestructured in hierarhy order with the assigned “weight”obtained from the “pairwise comparrison” technique.In this way all indicators have been assessed incorrelation with others and their weights have comefrom the mathematic model of organized hierarchystructure (AHP). With the AHP the level of subjectivityin assessment has been reduced on the base ofvalidated mathematic theory.

The integration model, as centrepiece of thisresearch, has been defined and tested in Ireland atthree different levels of planning: the regional level,county level and local level. However, this paper willrepresent model application on the strategic level ofplanning – South West Regional Authority RegionalPlanning Guidelines and particularly in the Cork AreaStrategic Plan (CASP) area.

MATERIALS & METHODSThe model was developed to integrate SEA into

the planning process and, in general, it is one segmentwithin a more comprehensive Spatial Decision SupportSystem. The models primary purpose is to assistplanners in understanding and recognising the

complexity of the problem and to provide decisionmakers with a proper basis in decision-making.The model (Fig. 1) is a GIS-MCDA application thatanalyses the conflict of two sub-models:Environmental sensitivity submodel and Developmentpressure submodel.Applying the model, the concept of sustainabledevelopment was actively involved in the planningprocess through interaction between environmentalsensitivity and planning indicators with the aim ofidentifying potential conflict zones.In general, the model intends to assist decision makersin recognising potential negative impacts of plannedactivities on the environment. The model has anadvisory rather than executive function. It simulatesthe potential conflicts on the basis of the adoptedindicators. By changing the inputs, or by changingindicator weights, the sensitivity map would bechanged and therefore conflict zones would beallocated. Due to the simulation characteristic, themodel may be useful for planners in selecting the mostsuitable alternative scenario. Therefore we can say thatmodel has also an optimization role.

The environmental sensitivity sub-model aims togenerate a cumulative environmental sensitivity map.This is a synthesis map of environmental elementsobserved in terms of the degree of their sensitivity toplanned activities. The sub-model aims to determinethe most sensitive areas from the standpoint of theenvironment and to guide decision makers to the mostoptimal (sustainable) direction for future developmentin order to achieve new development demands. Thissub-model can exist independently and out of the morecomprehensive Spatial Decision Support System. As astandalone module, the sub-model represents a veryuseful source of information for both planners anddecision makers regarding cumulative environmentalsensitivity.

The development pressure sub-model is based onpopulation and employment indicators. The populationdata came from the Census where we analysedpopulation growth in two census periods: 2002 and2006. Employment data may be within the generalcensus data or may arise from separate studies. In ourcase the employment data came from the POWCARdata source, which analysed information from theCensus.

The model is defined under the SEA terms thatrelate to the Republic of Ireland. Nevertheless, themodel could be applicable universally, but it’snecessary to calibrate it to local conditions. Since theSEA regulations are unique at EU level (SEA Directive),calibration is more related to local planning systemsrather than to local SEA systems.

Int. J. Environ. Res., 6(4):1053-1066, Autumn 2012

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Within the environmental sensitivity sub-model, theprocess begins with the establishment of indicators.Indicators are based on the cooperative work of SEAteam (in this particularly case) and external experts (EPAin our case) and methodologically indicators camethrough the application of the Delphi technique. Afterthe final list of indicators has been established, theindicators were organised within the AHP and assessedthrough pairwise comparison technique.It’s important to acknowledge that AHP procedure ismainly used to compare alternatives in order to get themost appropriate one. In this case the alternatives arethe final level of the hierarchical process.

In our case, we applied a different approach. TheAHP method was chosen as it is very useful forevaluating and comparing various types of data andtheir restriction to unambiguously defined hierarchicalstructure. In this case the aim is not selection of thebest suitable alternative, but to obtain an attribute(indicator) value that represents the importance ofattributes within hierarchical structures. The totalattributes value (“weight”) is relative attribute weight

Fig. 1. Concept of the Model

multiplied by the weight obtained through thehierarchical structure. The output from the process is“Criterion map” with the corresponding weight, whichis an input for GIS “overlay” process.Looking from the single criterion point of view, wecould represent the process with three main phases: 1. Standardisation 2. Weighting 3. AggregationThe “Criterion map” is a grid with accompanied“weight” obtained from the “pairwise comparison”technique and AHP structure. Criterion grid is goingto add to other criterion grids and thus becomes anintegral part of cumulative sensitivity map(fig.2).

The development pressure sub-model, as wenoted, was based on two basic indicators: populationand employment. Those two indicators could beassessed throughout two approaches: “conflict zonemanagement” and “land allocation”.Conflict zone management represents a concept whichis applicable on a regional level of planning and

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GIS Based Multicrteria Analysis

Fig. 2. The Model procedures and applied GIS-MCDA techniques

population and employment are categories which linkwith the planned development scenarios. In otherwords, at regional level the link between “developmentpressure zones – development scenarios” has beenestablished through population and employmentindicators. Within this link, development pressurezones are connected with development scenarios andchanges in development scenarios would meanchanges in development pressures zones and furtheringaddition, the conflict zones would also change.Therefore, the indicators get different values

depending on the scenarios that represent strategicplan objectives.

In applying the above approach, the model seeksto integrate the Plan scenarios with environmentalsensitivity and to simulate potential future conflictsbetween future development (represented withpopulation growth and higher employmentconcentration) and environment. It is up to decisionmakers to take responsibility for the scenario selectionhaving regard to the potential impact on theenvironment that the selected scenario may cause.

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RESULTS & DISCUSIONSW Regional Planning Guidelines is a strategic

document for southwest region development for theperiod 2010-2022. It is prepared by the SouthwestRegional Authority. The guidelines should ensure thesuccessful implementation of the National SpatialDevelopment Strategy at the regional level.The Southwest region includes the geographical areaof Cork City, Cork County and County Kerry.Administratively, those areas are incorporated intoLocal Authorities which taken together form the south-west region.

The SEA methodology applied in SW regionalplanning guidelines Environmental Report contain allthe phases (screening, scoping, etc) suggested by SEAGuidelines, but we will focus on the environmentalbaseline phase where the Model was applied.„Environmental baseline”phase of „EnvironmentalReport” has identified the main existing environmentalproblems and how they will be affected by RPG.

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SOIL AND GEOLOGY 1/4 3 1 1/3 1/3 3 1 7 5 WATER RESOURCES 1/3 5 3 1 1 4 3 7 5 AIR AND CLIMATE 1 4 3 7 5 CULTURAL HERITAGE 1 1/3 5 3 LANDSCAPE 1 7 4 MATERIAL ASSETS 1 1/3 FLOODING 1

Within the section of Environmental baseline weapplied the integration Model as correlation betweenenvironmental sensitivity sub-model and developmentpressure sub-model.

The environmental sensitivity sub-model wasbased on AHP and pairwise comparison technique, asstated in model definition. The SEA team prepared aquestionnaire with the preliminary ranking of mainindicators (Delphi technique). After the few phases ofa ranking process the final list of indicators wereestablished with their preliminary ranking. Indicatorswere organised in hierarchy structure and with pairwisecomparison technique every pair of indicators wasassessed in order to get their weight in the overallhierarchy system.The graph below (Fig. 3) shows thehierarchical structure of assessed indicators. The mainindicators pairwaise comparison matrix is shown inTable 1 while Table 2 represents the main indicatorswith the corresponding weights. The total sum of allweights according to AHP theory is equal to 1.

Table 2. The main indicators weight

INDICATOR WEIGHT BIODIVESITY 0.3 POPULATION AND HUMAN HEALTH 0.05 SOIL AND GEOLOGY 0.1 WATER RESOURCES 0.17 AIR AND CLIMATE 0.17 CULTURAL HERITAGE 0.06 LANDSCAPE 0.1 MATERIAL ASSETS 0.02 FLOODING 0.03 SUMMARY 1

Table 1. The main indicators pairwise comparison matrix

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After the main indicators weights were defined, all sub-indicators weights were calculated following thepairwaise comparison and AHP rules. For all other sub-indicators and criteria’s we followed the same principlein order to obtain their relative weights.The list of indicators, criteria and their relative weightscan been seen on the graph (Fig. 4) below.The final phase in the assessment process was tonormalise relative weight to the weight of higher levelin hierarchy structure in order to summarise all weightsin the system to 1. In the graph below (Fig. 5) you canfind final weighs.

The obtained weights from AHP we assigned tocriteria grids and through aggregation process (GISoverlay) we got a Cumulative Environmental SensitivityMap (Fig. 6) as a synthesis grid of all criterion grids.Within the Development pressure submodel, on thebasis of Census data, the population change wascalculated through the following criteria: highpopulation increase ED’s, low population increaseED’s, no change in population, low population decreaseED’s, high population decrease ED’s. The populationchange was based on Electoral division (ED)population census data for the period 2002 and 2006.The ED based population criteria were converted togrid with corresponding class of calculated populationchange.

The employment data was based on POWCARdata source where the job density was calculatedapplying the GIS point density tool. The developmentpressure zones are classified by the level of pressure,where the highest development pressure zones overlapwith high population increase or with the highestconcentration of jobs. So, development pressureszones are represented as zones with high populationincrease or strong employment zones.

Grid cell size depends of research areacharacteristics. In metropolitan area (Fig. 7) we chosevery small grid cell size of 250 m. The reason for this isthat we used POWCAR data source for the analysisand under the methodology they summarise jobs insquares 250x250 meters. So in addition, the appliedanalysis was also very useful for the employmentstrategy and RPG’s planners used the results of thisanalysis for developing local economic strategies.Areas of conflict are regarded as location wheredevelopment pressure areas and high vulnerable landoverlap.

The development pressure zone is connected todevelopment scenarios which mean that developmentscenarios will determine the level of developmentpressure zones. If the development scenario prefersstrong development and further urban sprawl that

means that development pressure zones will spreadand possibly more overlap with high environmentalsensitive areas.In the RPG the three scenarios were explored: 1.Continuation of current trends 2.High urban growth 3.Moderate urban growthThe stated three scenarios were analysed by 5 mainstrategic planning areas (Fig. 8): 1.Cork Gateway 2.CASP strategic planning areas 3.Tralee- Killarney strategic planning areas 4.West strategic planning areas 5.North strategic planning areasScenario 1: Continuation of urban trendsContinuation of urban trends has the following maincharacteristics: • High population growth in villages and rural areassurrounding the Cork Gateway and Tralee-KillarneyHub, • Decline in population growth within Cork City andTralee-Killarney Hub areas • Mallow Hub and other regional main towns willincrease in population • Increased number of commuters to Cork City andTralee-Killarney Hub •Rural communities will continue to declineScenario 2: High urban growthMain characteristics: •New development will be primary focused to Corkgateway and Tralee-Killarney and Mallow Hub • Population in Cork City will increase rapidlyespecially in northern suburbs of Cork City • Moderation of the rate of population growth invillages and rural areas within Gateway and Hub areas • Low rate of population growth in countryside inline with local employment opportunitiesScenario 3: Moderate urban developmentMain characteristics: • Moderate population growth in Cork City, Hubsand main towns where insufficient infrastructure wouldbe a highest restriction to reach the targeted population • Investment in Brownfield sites within Gatewayand Hubs

Because of the size limitations of this paper wewill only explain the assessment of CASP areascenarios.In the CASP area scenarios we explored developmentpossibilities following the context of Atlantic Gatewayinitiative, where the development corridor Cork-Limerick-Galway-Waterford was highlighted, as wellas an importance of Hub towns.

Also, we considered the areas suitable for ruraldiversification in order to explore possibilities for localeconomy development. Following the principles of

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Fig. 6. Cumulative environmental sensitivity map

Fig. 7. Metropolitan area jobs density grid

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Fig. 8. RPG’s main strategic planning areas

Fig. 9. Scenario 1


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Fig. 11. Scenario 3

Fig. 10. Scenario 2

National Spatial Strategy, the three areas weredesignated: • Village strengthening and rural area opportunities • Diversifying areas • Rural areas with string potential for diversification

Those areas are identified in the CASP area havingregard to cumulative environmental sensitivity whichmeans that rural diversification areas have to bedesignated in the low environmental sensitivity areas

but also in areas with strong potential for agricultureand forestry.With respect to the stated main developmentcharacteristics we applied the integration model tosimulate expected development pressure zones in orderto get possible conflict zones.In scenario 1 (Fig. 9) the development pressure zonesand possible conflict zones are located in line with themain road corridors: Fermoy-Cork and Mallow-Cork.

Therefore we can expect high commuting in the areaswhich could result in decreasing of quality of life andalso a decrease in the quality of air. Moreover, it’sexpected to have conflict with the archaeologicalheritage and biodiversity in Greenfield sites.

In scenario 2 (Fig. 10) the development pressurezones are more concentrated in Mallow Hub and maintowns. With this scenario it’s likely to expect moresustainable commuting because the main developmentwill be oriented towards urban centres, i.e. centres ofwork. The rural areas will experience population growthas they have strong potential for rural diversification,especially in area between Mallow and Macroom(Figure 10). In applying this scenario we could be facedwith infrastructure problems so it’s necessary to makeimportant investment in infrastructure in order toachieve targeted population.

In scenario 3 (Fig. 11) moderate population growthwas predicted because of infrastructure limitations andrestrictions in further infrastructural investments. Wecould expect moderate population growth in the MallowHub and main towns. Because of the limited investmentin infrastructure, and particularly in wastewatertreatment, we can also expect important impacts on thewater quality of the River Lee and Blackwater. In thisscenario few areas suitable for rural diversification weredesignated.

In general, 40% of CASP area is regarded as highvulnerable. The development corridor, based onAtlantic gateway corridor and hub towns, could bestrongly effected with new development which couldhave a significant impact on the environment.In the Environmental Report it was stated that “themain environmental considerations in the CASP areais the protection of agriculture productive lands, theprotection of site integrity and the environmentalconditions necessary to support the site integrity ofNatura 2000 sites, achieving the Water FrameworkDirective River Basin management objectives andincreasing sustainable commuting.” (EnvironmentalReport, page 132).

Therefore, analysing the RPG’s main developmentobjectives we could say that Scenario 2 is the mostpreferable scenario from an environmental point of view,but also from the RPG main objectives point of view.As the RPG supports the ER preferred scenario(Scenario 2) for CASP area all individual objectiveswere assessed in the assessment matrix in order toascertain their environmental effect.

CONCLUSIONThe presented model has tried to give one more

perspective in the integration of the SEA process into

planning. Unlike other methods the SEA process isactively involved in the planning process. The modelenables simulation of results and therefore can be veryuseful for planning simulations.

An important feature of this model is the planningbasis. The model is not a separate expert system forevaluating the environmental impact, instead it’s anactive model guided by planning principles inconsidering the impacts of the planned activities tothe environment. Therefore, this model is seen as atool developed for planning purposes.

The model and the presented approach is anattempt to involve GIS-MCDA concept intoenvironmental planning. The critical segment of theresearch is how to reduce subjectivity in preliminaryranking? In the model the Delphi method was usedand, in general, the Delphi method could reduce thelevel of subjectivity but still all individual ranking wasbased on subjectivity judgement. Also, within thedevelopment pressure sub-model the employmentindicator was based on POWCAR data source, with“place of work” data, which could be a problem in thecases where we don’t have “place of work” data withinthe Census. Because of this restriction the sub-modelcould not be universally applied.To conclude, the model has pasted severaldevelopmental stages and the presented one iscertainly not the final. As planning and SEA areprocesses in their essence - the presented MCDA-GIS-oriented model is a process that will improve withthe improvement of planning theory and SEA.

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Environment Management and Applied System Analysis”,Nakayama, H. and Makowski, M., International Institutefor Applied Systems Analysis, Austria.Malczewski, J. (2003); “GIS based land use suitabilityanalysis, a critical overview”, Elsevier, Canada.

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