Resource Guidance for EIA

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ResourceandGuidanceManualforEnvironmentalImpactAssessments

Desa

lination


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ii

DesalinationResourceandGuidanceManualforEnvironmentalImpactAssessmentsTheworld'soceanshavealwaysbeenasourceoffoodandothergoods.The in

dustrialscaleproductionofdrinkingwater from thesea,however,hasonlybe

come possible since the 1950s. Today the worldwide number of desalination

plantsincreasesatrapidpace,asproductioncostsofdesalinatedwaterhavede

clinedandmanyregionsturntodesalinationinordertoalleviatetheburdensof

waterscarcity.Desalinationundoubtedlyoffersawidevarietyofbenefitsforhu

manhealth

and

socio

economic

development.

It

provides

aseemingly

unlimited,

draughtresistantandconstantsupplyofhighqualitydrinkingwaterwhilereduc

ingthepressuresonfreshwaterecosystemsandgroundwateraquifers.

Inspiteoftheseadvantages,concernsareraisedoverpotentialnegativeimpacts

ofdesalinationactivityon theenvironment.Theseneed tobe investigatedand

mitigated inorder to safeguard a sustainableuseofdesalination technologies,

whichcanbeattainedbyconductingproject andlocationspecificenvironmental

impactassessment(EIA)studies.Thispublicationintendstoassistprojectdesign

ers,regulatorsanddecisionmakerstoanticipateandaddressallrelevantpublic

health,socioeconomicandenvironmentalconcernsthatmayarisewhenunder

takingadesalination

project,

for

obtaining

maximum

beneficial

use

of

the

desali

natedwaterintermsofquality,safetyandenvironmentalprotection.

WHO/EMRO

WorldHealthOrganization

RegionalOfficefortheEasternMediterranean

P.O.Box7608

NasrCity,

Cairo

11371

Egypt

Telephone:+2026702535

Fax:+2026702492/94

Email:[email protected]

www.emro.who.int

UNEP/ROWA

UnitedNationsEnvironmentProgramme

RegionalOfficeforWestAsia

P.O.Box10880

ManamaKingdomofBahrain

Telephone:+97317812777

Fax:+97317825110/17825111

Email:[email protected]

www.unep.org.bh


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DesalinationResourceandGuidanceManualforEnvironmentalImpactAssessments

UNEP/ROWA2008

ISBN:9789280728408

SuggestedCitation:UNEP(2008)DesalinationResourceandGuidanceManualfor

Environmental ImpactAssessments.UnitedNationsEnvironmentProgramme,

RegionalOfficeforWestAsia,Manama,andWorldHealthOrganization,

RegionalOfficefortheEasternMediterranean, Cairo

Principalauthorandeditor:SabineLattemann

Coauthors:

Khalil

H.

Mancy,

Bradley

S.

Damitz,

Hosny

K.

Khordagui,

Greg

Leslie

Pictures(ifnotstatedotherwise):SabineLattemannandThomasHpner,

RaniAmir(frontcovertopright).

ThecontentsofthisreportdonotnecessarilyreflecttheviewsorpoliciesofUNEPor

contributoryorganizations. Thedesignationsemployedandthepresentationsdonot

implytheexpressionsofanyopinionwhatsoeveronthepartofUNEPorcontributory

organizationsconcerningthelegalstatusofanycountry,territory,cityorareaorits

authority,orconcerningthedelimitationofitsfrontiersorboundaries.

TheEuropeanCommunityisnotliableforanyusethatmaybemadeoftheinformation

containedherein.Thepublicationreflectstheauthorsviewsonly.

iii


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iv

Editor:Sabine Lattemann

heauthorwouldliketoextendthankstoall

individuals and organizations that made

thispublicationpossible.HoussainAbouzaidand

JosephCotruvo

have

been

instrumental

ininitiating,coordinatingandguiding

theprocesswithintheprojecton

Desalination for Safe Water

Supply, which was carried

out under the auspices of

the World Health Organ

ization, Eastern Mediter

ranean Regional Office

(WHO/EMRO).Ithadthe

objective

to

develop

guidance for the health

and environmental as

pectsapplicabletodesa

lination projects. Special

thanks go to Khalil H.

Mancy,BradleyS.Damitz,

Hosny K. Khordagui, Greg

Leslie and Klaus Genthner

fortheirdedicatedparticipa

tionin

this

project

and

for

co

authoring this publication.Work

groupmeetingswereheldbyWHO/

EMRO in the years 2004, 2005 and

2006,forwhichadditionalsponsoringwasre

ceived from the U.S. Environmental Protection

Agency's National Risk Management Research

Laboratory,theAmericanWaterWorksAssocia

tionResearchFoundation(AwwaRF),TheKuwait

FoundationfortheAdvancementofScience,the

WaterAuthorityoftheCaymanIslands,theU.S.

Bureau of Reclamation, AGFUND, and the Na

tionalWater

Research

Institute

(NWRI,

USA). Members of the projects

Oversight Committee included

Houssain Abouzaid (WHO/

EMRO,Cairo), JamieBartram

(WHO/WSH, Geneva), Ha

bibElHabr (UNEP/ROWA,

Bahrain), Abdul Rahman

Al Awadi (ROPME, Ku

wait),andJosephCotru

vo(Joseph

Cotruvo

&

Associates LLC, USA).

TheSteeringCommittee

members consisted of

Amer AlRabeh (Saudi

Arabia), Anthony Fane

(Australia), Gelia Frede

rickvan Genderen (Cay

man Island), Totaro Goto

(Japan), Jose Medina San

Juan(Spain),

and

Kevin

Price,

USA. Funding was furthermore

received from the European Com

munity,which fosters the sustainable

development ofdesalinationprocessesby fi

nancing theresearchprojectMembraneBased

Desalination:AnIntegratedApproach(Acronym

MEDINA, 20062009) within the scope of the

SixthFrameworkProgramme(FP6).

TAcknowledgements


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v

or drinking water quality specifications,

many countries refer to theWorldHealth

Organization (WHO) Guidelines for Drinking

WaterQuality

(DGWQ).

The

guidelines

provide

a framework forensuring the safetyofdrinking

watersuppliesthroughthecontrolofhazardous

waterconstituents.Theycoverabroadspectrum

of contaminants, from microbial indicators to

chemicals,andareaimedattypicaldrinkingwa

tersourcesandtechnologies(WHO2004).

As desalination is applied to nontypical

sourcewaters(mainlywastewater,brackishand

seawater) and often uses nontypical water

treatmenttechniques

(including

distillation,

re

verseosmosis,ultra,micro andnanofiltration),

the concern was raised that the GDWQ might

not fully cover the unique factors that can be

encounteredduringtheproductionanddistribu

tionofdesalinateddrinkingwater.

In 2004, the World Health Organization has

therefore initiatedaprocess toprepareaguid

ancedocumentonDesalination forSafeWater

Supply,whichwillsupplementtheWHOGuide

linesfor

Drinking

Water

Quality

(WHO

2007).

The guidance document is equally concerned

with health and environmental aspects of de

salinationdevelopments.

Health issues are primarily reflected in re

spect topotential chemical andmicrobial com

ponentsthatarespecifictodesalinateddrinking

water. Environmental aspects, which are nor

mallynot covered indetailbyWHOguidelines,

were in this case includedbecause theprotec

tionof

coastal

ecosystems

and

groundwater

aq

uifers from desalination plant discharges were

consideredkeyconcernsthatshouldalsobead

dressedduringthedesign,constructionandop

erationofadesalinationfacility.

Fivetechnicalworkgroupswereestablishedthat

addressed the followingaspectsofdesalination

duringtheproject:

Technology:engineeringandchemistryHealth:contaminantsandnutritionalaspectsSanitaryaspectsandmarinemicrobiologyMonitoringrequirementsEnvironmentaleffectsandimpact

assessments

Independent from thesedevelopments, theEu

ropean Community has decided to foster the

sustainableuseofdesalinationprocesses in the

EUby

financing

the

research

project

MEDINA

(MembraneBased Desalination: An Integrated

Approach) within the Sixth Research Frame

work (FP6).Theprojectsoverallobjective is to

improve the performance of membranebased

waterdesalinationprocessesby:

developingadvancedanalyticalmethodsforfeedwatercharacterization

optimizingintegratedmembranesystems identifyingoptimalpretreatmentand

cleaningstrategies

for

membrane

systems

reducingtheenvironmentalimpactsofbrinedisposalandenergyconsumption

developingstrategiesforenvironmentalimpactassessment(EIA)studies.

TheMEDINAproject integratesandbuildsupon

the findingsof the recentWHOproject forde

veloping strategies on how to minimize envi

ronmental impacts and conduct environmental

impactassessment

studies.

This

report

combines

results and recommendations of the environ

mentalworkgroupthatcouldonlypartlybe in

cluded intheWHOguidance,andrecentresults

fromtheMEDINAresearchproject.

FPreface


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vi

ydefinition, anEnvironmental ImpactAs

sessment (EIA) isaprocedure that identi

fies,describes,evaluatesanddevelopsmeansof

mitigatingpotential

impacts

of

aproposed

activ

ityontheenvironment.EIAscanbecarriedout

forsingledevelopmentprojects(projectEIAs)or

forstrategicplans,policiesormanagementpro

grammes, such as integrated water resources

management (IWRM) plans. Strategic EIAs will

notmakeEIAs at theproject leveldispensable;

botharerathercomplementinginstruments.

AdetailedEIA isoftenrequiredformajor in

frastructure projects, such as large dams or

powergeneration

plants.

For

relatively

small

projects,asimplifiedEIAmaybewarranteddue

to the limitedpotentialof theproject to cause

significant environmental impacts. In principle,

EIAs for desalination projects will not differ in

terms of complexity and level of detail from

thoseforotherinfrastructureprojectsandespe

ciallyotherwatersupplysystems.Dependingon

theproposedproject,itisincumbentonnational

authoritiestoindividuallydefinetheneed,scope

andcomplexity

of

each

EIA

study.

EIAsareusuallynotlimitedtoenvironmental

aspects, but typically address all potential im

pactsofnewprojects,plansoractivitiesonman

and environment. This may require an inter

disciplinaryapproach,coveringdifferentnatural

and environmental science disciplines. Taken a

step further in relating potential impacts to

peopleand communities, itmayalsobeneces

sary to consider human health and socio

economicaspects

where

appropriate.

Public

par

ticipation is another fundamental element of

EIAsinorderto involvethepublicintheevalua

tion and decisionmaking process of new pro

jects.Wherepossible,anEIA should try topre

dictallpotentialimpacts,includingthosedirectly

and indirectlyrelatedtoaproject,aswellascu

mulative impacts with other projects or activi

ties,andtransboundaryeffects.

ReadersGuide

With the context so broad, the present docu

mentcannot

fully

encapsulate

the

whole

spec

trum and depth of implications of all possible

desalinationprojects.Thedocument tries tobe

inclusiverather thanexclusivebyraisingawide

rangeofpotentiallyrelevant issuesattendantto

the use of desalination as a community water

supply, includingenvironmental, cultural, socio

economicandhumanhealthimplications.Based

on the information provided in this document,

thereadershoulddecideonacasebycasebasis

whichissues

may

be

relevant

to

aparticular

de

salinationproject.

Thedocument isdivided into threeparts. In

PartA, an introduction to the concept,metho

dology and practice of EIAs is given. The EIA

process proposed for desalination projects in

volves10basicsteps. It isnot limited todesali

nationplants,butcanbeappliedtootherwater

infrastructureprojectsinasimilarmanner.

InPartB,amodularoutlineofanEIA report

fordesalination

projects

is

proposed.

It

gives

an

overviewonarangeofthematicissuesthatmay

berelevanttoindividualdesalinationprojects.It

mayalso serveasa reference sourceandblue

printforpreparingEIAreports.AstheEIAreport

presents and summarizes the information ga

thered during the EIAprocess, the structureof

partBisreflectingthestructureofthemethodo

logicalapproachdescribedinPartA.

PartCgivesanoverviewonthepotentialim

pactsof

desalination

plants

on

the

environment,

based on a comprehensive literature review.

Moreover, an attempt ismade to evaluate the

identified concerns in termsof significanceand

relevanceforEIAstudies,usingformalcriteria.

Theappendicesprovidemoredetailed infor

mationonprojectscreeningandscoping,which

constitutethefirsttwostepsofanEIA.

BExecutiveSummary


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vii

Keyfindingsandrecommendations

I. AnEIA should try topredict all impacts

relateddirectlyor indirectlytothe implementa

tionofadesalinationproject.Thiscomprisesall

environmentalimplications

including

ecosys

tem, socioeconomic, and public health effects

andtheircumulativeandtransboundaryimplica

tionsasanintegralpartoftheprocess.Itshould

attempttoidentifythepositiveeffectsandoffer

mitigationmeasuresfornegativeimpacts.

In essence, an EIA for a desalination project

shouldaddressthefollowingareasofimpact:

AbioticandbioticenvironmentAbiotic factors include characteristic land

scapeandnaturalscenery,aswellassoilsand

sediments,airandwaterquality.

The biotic environment encompasses theterrestrial

and

marine

biological

resources,

including flora, fauna and sensitive species

that inhabit the area impacted by the pro

posedproject.

SocioeconomicandculturalenvironmentSocioeconomic and cultural considerations

include the projects effects on the dayto

day livesof the individuals and the commu

nity,theprojectsimpactonthemanagement

ofnatural

resources

and

the

projects

impact

onlocalandregionaldevelopment.

Genderspecificeffectsandvariationsamongthe potentially affected population or com

munity, such as social or ethnic affiliations,

should be considered in the assessment of

socioeconomicandculturalimpacts.

PublichealthPublic health addresses the quality of life,

improvement in community health, and po

tential risks associated directly or indirectly

withthedesalinationproject.

II. The EIA process proposed for desalina

tion developments and other water supply

projectsinvolvestenbasicsteps:

1. Decide,onthebasisofascreeningprocess,whetherornotanEIAis

requiredfortheproposedproject.

2. ConductscopingtodeterminethecontentandextentoftheEIA.

3. Identifypolicyandadministrativeaspectsrelevanttotheprojectand

theEIA.

4. Describethetechnicaldesignandprocessoftheproposeddesalination

project.

5. Describeandassesstheenvironmentalbaselineoftheprojectsite.

6. Describeandevaluatethepotentialimpactsoftheprojectonthe

environment.

7. Identifyapproachesformitigationofnegativeimpacts.

8. Provideasummaryofthemajorfindingsanddevelopconclusions.

9. Establishaprogrammetomonitorimpactsduringconstructionand

operation.

10. ReviewtheEIAprocessfordecisionmakingpurposes.


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III. As EIAs are undertaken before projects

areimplemented,theycanonlygiveaprognosis

of theexpected impactsbasedon the informa

tionavailableat that time,even if theEIAsare

basedupondetailedanalyses.Itisthereforeim

portantto

clearly

identify

any

gaps

of

knowledge

in the EIA and to adopt a precautionary ap

proachintheevaluationofpotentialimpacts.

Furtherremarks

Thedocument recognizes that theneed forde

salination to augmentwater supplies varies re

gionally. Also, environmental settings, cultural

backgrounds,socio

economic

development

and

humanhealthconditionsarehighlyvariableand

showmajorregionaldifferences,asdoestheuse

ofdesalinationtechnologywithregardtofacility

size, processes, pretreatment systems and dis

chargeoptions(cf.Introduction).

IV. Public involvement isan integralpartof

theplanning,decisionmaking and implementa

tionprocessofdesalinationprojectsforcommu

nitywatersupply.

No universally valid standards for environ

mental quality, best techniques or acceptable

risksofdesalinationexistnor shallbeprovided

withinthisdocument.Theconsiderationofben

efitsversus

impacts

of

desalination

develop

ments canonlybeachieved at a local,project

specificlevel.

V. Inorder tomanage increasingdesalina

tionactivity

on

anational

or

regional

scale,

it

is

recommended to elaboratemanagement plans

whichgobeyond thescopeof individualdesali

nationprojects.Themost relevantplans toad

dressdesalinationprojectsalongwithotherwa

ter supply alternatives are integratedwater re

sources management (IWRM) and integrated

coastalzonemanagement(ICZM)plans.

If awater resourcemanagementplan isde

veloped, it should cover a suite of supply, de

mandand

management

options.

Water

conser

vation and education programmes, the use of

water saving devices and water recycling for

agricultural, industrial andenvironmental appli

cations are important aspects tobe considered

beforenewwatersupplyoptionsaredeveloped.

AlthoughthisreportprimarilyaddressesEIAs

on theproject level, it isemphasized that stra

tegic plans and assessments could be a more

adequate approach to manage water demand

andsupply

on

aregional

or

even

national

scale.

VI. Despite a 50 yearhistory of large scale

desalinationprojects, thepresentknowledgeof

theenvironmental,socioeconomic,culturaland

humanhealthimplicationsofdesalinationactivi

ty isstill incomplete.Moreresearch intotheef

fects shouldbe initiated,monitoringofexisting

facilitiesconducted,andmonitoringandEIA re

sultsmadeavailabletoawiderpublictoimprove

ourunderstanding

of

the

actual

impacts

of

desa

linationactivityonmanandenvironment.

viii


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B.7 Socioeconomicandenvironmentalhealthaspects 33

B.7.1 Population,housingandcommunitystructure 33

B.7.2 Economicgrowthanddevelopmentactivities 33

B.7.3 Environmentalhealthfactors 34

B.7.4 Waterresourcesuse 36

B.7.5

Landand

marine

use

37

B.7.6 Utilitiesandservicesystems 38

B.7.7 Culturalresources 38

B.8 Abioticenvironment 39

B.8.1 Characteristiclandscapeand naturalscenery 39

B.8.2 Terrestrialsite (soils,ground andsurfacewater) 40

B.8.3 Marinesite (seafloor,sedimentsandseawater) 41

B.8.4 Airqualityandclimate 42

B.9 Bioticenvironment 44

B.9.1 Terrestrialbiologicalresources 44

B.9.2

Marine

biological

resources

45

B.10 Conclusionandrecommendations 46

B.10.1 Overviewonthemainimpactsoftheprojectandmitigationmeasures 46

B.10.2 Comparisonwithalternative projectconfigurations 47

B.10.3 Identificationofthebest practicableenvironmentaloption 47

B.11 Environmentalmanagementplan 47

B.11.1 Monitoring 48

B.11.2 Surveillance 48

B.11.3 Auditing 48

B.12 ReviewoftheEIAprocess 49

B.13

Referencesof

the

EIA

49

B.14 AppendicesoftheEIA 49

x


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xi

PartC Potentialimpactsontheenvironment

C.1 Ecologicalriskassessments 50

C.1.1 Stressors 51

C.1.2 Receptors 51

C.2 Constructionactivities 52

C.2.1 Intakesandoutfalls 52

C.2.2 Desalinationplant 58

C.2.3 Auxiliaryinfrastructure 61

C.3 Commissioning 64

C.4 Operation 64

C.4.1 Intakeofseawater 64

C.4.2 Pretreatmentofseawater 66

C.4.3 Corrosion 73

C.4.4

Discharge

of

the

concentrate

74

C.4.5 Dischargeofresidualchemicals 93

C.4.6 Hazardsandhazardousmaterials 95

C.4.7 Noiseemissions 95

C.4.8 Energyuse 95

C.5 Maintenance 100

C.5.1 Startupandshutdown 100

C.5.2 Cleaning 101

C.6 Decommissioning 104

C.7 Evaluationofsignificance 105

C.7.1 Methodology 105

C.7.2 Evaluation 107

PartD Appendices

D.1 Appendix1Guidanceforscreening ofdesalinationprojects 122

D.1.1 Informationrequiredforscreening 122

D.1.2 Screeningchecklist 123

D.1.3 Criteriafordefiningsignificance 129

D.1.4 Summaryoffeaturesoftheprojectandofitslocation 129

D.2 Appendix2

Guidance

for

scoping

of

desalination

projects

130

D.2.1 Checklistofprojectcharacteristicsthatcouldcausesignificanteffects 130

D.2.2 Characteristicsoftheproject environment 141

D.3 Appendix3Ecotoxicitydata 143

Bibliography 147


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FiguresFigure 1: RelativeoperationcostsinUS$ofthemaindesalinationprocesses 2

Figure 2: Pre orearlyEIAphases(scopingandscreening)and mainEIAphase 6

Figure 3: EIAdecisionphaseandfollowupactivities 7

Figure 4: Deploymentofarealtimemonitoringbuoy,PerthSWROplant 49

Figure

5:

Open

intake

basin

with

breakwater 53Figure 6: Constructionofasheetpiletrench, PerthSWROplant 56

Figure 7: FlowschemeofaSWROsystem 67

Figure 8: FlowschemeofaMSFdistillationplant 67

Figure 9: Chemicalstructuresofcommonantiscalants 72

Figure 10: Posidoniaoceanicaseagrassmeadow 79

Figure 11: Periodicdischargeoffilterbackwash,AshkelonSWROplant 92

Figure 12: Energyrecoverysystems 96

Figure 13: Energyrecoveryturbine 96

Figure 14: ChemicalstructuresofcommonROcleaningchemicals 101

Figure 15: Pretreatmentchemicalsandpretreatmentdosingsystem 104

Figure 16: Decisionhierarchyusedtoidentifyhighandlowpriorityimpacts 106

Table 1: Compositionof254SMOsuperausteniticsteel 74

Table 2: CalculatedsalinityofROplantrejectstreams 76

Table 3: EnergydataofMSF,MEDandRO 98

Table 4: Carbondioxideemissionfactors 99

Table 5: Europeanenergymixin2005 99

Table 6: ProposedcleaningprocedureforHydranauticspolyamidemembranes 102

Table 7: Membranecleaningsolutions 103

Table 8: Significanceratingsforevaluationcriteria 106

Table 9: Impactsummary:Landscapeandnaturalscenery 108

Table 10: Impactsummary:Airqualityandclimate 109

Table 11: Impactsummary:Terrestrialsoils 110

Table 12: Impactsummary:Groundandsurfacewaterqualityandhydrology 111Table 13: Impactsummary:Seafloorandsediments 112

Table 14: Impactsummary:Seawaterqualityandhydrology 113

Table 15: Impactsummary:Terrestrialflora 115

Table 16: Impactsummary:Terrestrialfauna 115

Table 17: Impactsummary:Marinemacroflora 116

Table 18: Impactsummary:Marineplankton 117

Table 19: Impactsummary:Marinebenthicinvertebratefauna 118

Table 20: Impactsummary:Marinenekton 119

Table 21: Impactsummary:Marinemammalsandreptiles 120

Table 22: Impactsummary:Terrestrialbirdsandseabirds 121

Table 23: Screeningchecklist 124

Table 24: Projectcharacteristicswhichcouldgiverisetosignificanteffects 132Table 25: Chlorinetoxicity 143

Table 26: Chlorinationbyproducts 143

Table 27: Antiscalanttoxicity 144

Table 28: Antiscalantdegradability 145

Table 29: Cleaningchemicaldegradability 145

Table 30: Cleaningchemicaltoxicity 146

Tables

Box 1: Noiseemissions 57

Box 2: Overviewonfieldandmodelingstudies 80

Box 3: Overviewonsalinitytoleranceandtoxicitystudies(bioassaystudies) 87

Box 4: Toxicitycausedbycodischargewithwastewaterfromsewageplants 91

Textboxes

xii


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1

ater scarcity can be a serious impedi

ment toeconomicgrowth,socialdevel

opmentandhumanhealth. It furthermoremay

causesevere

ecosystem

damage

ifwater

ab

stractionratesexceednaturalrenewalrates.To

cope with water scarcity, many communities

aroundtheworldturntonontypicalsourcewa

tersand treatment techniques, such as rainwa

ter harvesting, water reuse or desalination of

sea andbrackishwater.

Desalination has been a wellestablished

technologysincethemidtwentiethcentury.Un

tila fewyearsago, largescaleprojectswere li

mitedtoafew

arid

countries

ofthe

Middle

East,

which had the financial and natural resources

andnootherwatersupplyoptions.Today,desa

linated water has become a commodity for

manyotherregionsthatrequiremorewaterfor

socioeconomic development. Regional centers

ofdesalinationactivitythatbecomemoreprom

inent include for example the Mediterranean

Sea, theRedSea, theCaribbean,or the coastal

watersofChinaandAustralia.

Sectorsofuseandinstalledcapacities

Desalinatedwaterservesabroadrangeofappli

cations,includingcommunitywatersupply,tour

ism, industry,militaryandagriculture.Themain

sectorsofuse,however, remain tobedrinking

water forcommunities,touristresortsandpure

waterfor industries,whereasdesalinatedwaste

waterisstillprimarilyusedforirrigation.

Thecombined

production

ofalldesalination

plantsworldwide,whichareknowntobeincon

structionoronline,was44.1millionm3perday

bytheendof2006.Wastewaterdesalinationac

counted for 5% of this production, riverwater

for8%,brackishwaterfor19%andseawaterfor

63%[1].28millionm3ofwaterperdayarepro

ducedbyseawaterdesalinationplantsalonea

volumecomparabletotheaveragedischargeof

theSeineRiveratParis.Thedesalinationmarket

hasbeen

growing

rapidly

atacompound

av

eragerateof12%ayearoverthepastfiveyears.

The rate of capacity growth is expected to in

creaseeven further, reaching64millionm3per

dayby2010and98millionby2015.Theprogno

sisisbased

on

country

by

country

analyses

in

volvingdesalinationprojectsandofficialdataon

watersupplyanddemandfromagenciesaround

theworld[2].

As desalination technology serves a broad

spectrumofusesandapplications, facilitiesdif

fer in termsofproductioncapacity,processde

signandenergy supply.They range from small

scale,standaloneunitswithawaterproduction

of less than 100m3perday to large industrial

sizedplants

with

an

installed

capacity

ofmore

than1millionm3perday.

In the oilrich countries of theMiddle East,

largecogenerationfacilitiespredominate,which

produceelectricityandwateratthesametime.

Historically, themost important process in the

Gulfregionhasbeenmultistageflash(MSF)dis

tillation,bywhich90%ofthewaterisproduced.

MSFwillcontinuetobethemainprocess inthe

foreseeable future,butwill lose furthermarket

sharestomulti

effect

distillation

(MED)

and

re

verseosmosis(RO).Thecombinedcapacityofall

seawaterdesalinationplantsintheGulfisabout

12millionm3perday,or slightly less thanhalf

(44%) of the worldwide daily production. The

largestproducersofdesalinatedwaterinthere

gionandworldwideareSaudiArabia (25%)and

the United Arab Emirates (23%), followed by

Kuwait(6%ofworldwideproduction).

Where cheap fossil energy orwaste heat is

notavailable,

RO

isusually

the

preferred

desali

nation technology due to its lower energy de

mand compared to thermal desalination pro

cesses. Consequently, most countries outside

theMiddle East use RO for water production.

For example, 70% of the desalinated water in

theMediterraneanregionisproducedbyseawa

terROplants.Thetotal installedcapacity inthe

Mediterranean is 4millionm3 per day (14% of

theworldwidetotal).Thelargestproducerofde

salinatedwater

inthe

region

isSpain

(8%

of

worldwide production), while the largest RO

WIntroduction


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2 DesalinationResourceandguidancemanualplant with a daily production of 330,000 m3 is

currentlylocatedinAshkelon,Israel,butprojects

ofsimilarsizearebeingalsoplannedinAlgeria.

In the foreseeable future, Saudi Arabia and

theUnitedArabEmirateswillcontinuetobethe

largest desalination markets. China is expected

todramaticallyexpanditscapacityandestablish

itself as the third most important desalination

marketuntil2015,overtakingSpain,Algeriaand

othercountriesthatareatthemomentranking

atthetopofthelist[2].

Costandenergyimplications

Desalinationprojectsare typicallydrivenby the

limited availability of conventional freshwater

resources.However,asconventionalwaterpro

ductioncostsriseinmanypartsoftheworldand

thecostsofdesalinationdeclinedue totechno

logicaladvances,desalinationalsobecomeseco

nomicallymoreattractiveandcompetitive.

Forillustration,amediumsizedROplantwitha

capacity of about 25,000 m3 per day and an

energy demand of 5 kWh per m3 would con

sume about 125,000 kWh per day. The plant

could supply more than 41,000 fourperson

householdswithwater,whiletheenergythatis

used for thedesalination process could supply

morethan9,000householdswithelectricity(as

suming a water consumption of 150 liters per

person and day and an average electricity de

mandof5000kWh/year fora4personhouse

hold). Energy demand is thus a major issue in

theplanningandpermittingprocessofnewde

salinationplantsand is closely interlinkedwith

power supply and power management strate

gies.

Fossil fuels are typically used as primary

energy source for producing the electrical or

thermalenergy.Renewableenergydrivendesa

lination technologies using wind or solar ther

malenergyexistbutaremostlylimitedtosmall

units or demonstration projects. For large

plants,compensationseemstobeamoresuita

ble approach. For example, a 144,000 m3 per

dayROplantinPerth,Australia,wasassociated

witha80MWwindfarmtocompensateforthe

electricity demand of the plant, and the

140,000m3 per day Thames Water plant near

Londonwasproposedto berunonbiodiesel.

Theaverageinvestmentcostrequiredforen

gineering, procuring and constructing an MSF

plant isgivenasUS$1,235perm3/day installed

capacity.CapitalcostsforMEDandROplantsare

lowerwithUS$916andUS$641perm3/dayin

stalled capacity, respectively [2]. The average

productioncostsofdesalinatedwaterareinthe

rangeofUS$0.5to0.6perm3.Thisincludesthe

replacementofpartsandmembranes,chemicals

for pretreatment of the intake water, plant

cleaningandposttreatmentoftheproductwa

ter, labour costs, and energy demand as the

mostimportantcostfactor(Figure1).

The amount of energy needed for water

production is processdependant: MSF plants,

having a maximum operating temperature of

120C, typically require 12kWhof thermal and

3.5kWhof electricalenergy for theproduction

of1m3ofwater.MEDplants,whichoperateat

temperatures of70C or less, require 6kWh of

thermaland1.5kWhofelectricalenergyperm3

ofwater.TheROprocess consumesbetween4

and7kWhperm3dependingonplantsizeand

energyrecoverysystemsused[3].

Figure1: RelativeoperationcostsinUS$ofthe

main

desalination

processes

[2].


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Introduction 3

Communityandequityconsiderations

Desalination projects like other water infra

structureprojectsoftenconsumeconsiderable

communityresourceswhichmaynotbereflect

edintheinvestmentandoperatingcosts.These

maybeintheformoffinancialsubsidies,access

tocoastalland,ortheprovisionofsupportingor

connectinginfrastructure.Thedesalinatedwater

should thereforebevaluedasacommunityas

set.Inadditiontoconsideringthemeasuresout

linedinthisdocumenttoassessandmitigatepo

tentialimpactsoftheproductionprocessonthe

environment, on socioeconomic development

andonpublichealth,communitiesshouldvalue

thedesalinatedwaterbynonwastefuluseand

bylookingforopportunitiesofmultipleuse.This

mightbeattainedbyadoptingwater allocation

policiesandpricingmethodsthatfosteraneco

nomicuseofthewaterresources.

Itappearsreasonabletorequestthatanypol

icy or pricing model used for the allocation of

desalinated water will not be contrary to the

public interest, if the production process in

volved a contribution of community resources.

Moreover, the allocation of desalinated water

shouldsatisfytwocriteria.First,thedesalinated

watershouldbeallocatedinacosteffectiveway

sothattheoverallbenefitsfortheservedpopu

lation are maximized. However, maximization

alonemaynotbesatisfactory if itmeasuresthe

sumofcostsandbenefitsonly,but ignores the

pattern of their distribution across the popula

tionaffectedbyadesalinationproject.

Equityconsiderationsshouldthusbeincorpo

ratedasasecondimportantcriterionintheallo

cationandpricingmodel fordesalinatedwater.

Ithasthegoalofanequitableandjustdistribu

tionofthebenefitsandcostsofdesalinatedwa

ter among distinct stakeholder groups or indi

viduals.Equityconsiderationsinwaterallocation

can be a complex undertaking and no general

rules exist, but allocations ignoring equity con

siderations are unlikely to produce satisfactory

resultsinthelongrun.

Impactsonpovertyanddevelopment

Poverty is inextricably linked with water and

foodsecurity,humanhealth,environmentalsus

tainability and socioeconomic development in

manypartsof theworld.The linksarewellun

derstoodandwidelydocumented.Tobreakthe

vicious circleofpovertyalsomeans to improve

watersecurityforthepoor.Thisimpliesimprov

ingwatermanagement practices and providing

access towaterofsafequalityand inadequate

quantity, so that basic personal requirements

canbemetandalivelihoodprovided.

While desalination is vital for economic de

velopment in many water scarce areas of the

world, one has to be skeptical whether it can

havemuch effect onpoverty reduction in eco

nomicallylessdevelopedcountries.Thecostsof

buildingalargedesalinationplantareunattaina

ble formanyof thepoorest countries.Further

more,operatingsuchafacilityrequiresongoing

expenses and technical efforts. Even if the in

vestmentandoperatingcosts foradesalination

plant canbeprocured, thisdoesnotautomati

cally imply thatthepoorest inasocietywillget

an equitable share of the benefits. A central

problemofwater poverty inmany countries is

afteralltheinequitableallocationbetweencon

sumers (in addition to pollution and misma

nagement)ratherthantheabsenceofwaterre

sources.Desalination cannotposea solution to

theproblemofwater scarcitywithoutaddress

ingtheserootcausesofwaterpoverty,whichof

tenstrikesthepoorestinasociety.

As the production of desalinated water re

quiresconsiderableenergyandcapital,itisoften

usedasasupplementalresourceonly.Exceptfor

afewcountriesintheMiddleEastandsomeisl

ands,whichdependalmostexclusivelyondesa

linated water, conventional resources still ac

countformostofthewatersuppliesworldwide.

Desalination projects are often proposed al

though there is stillpotential for improving the

conservation and efficiency of use of conven

tionalresources.Thisalsoholdstrueforlessde

veloped countries,where itmaybemore cost

effective to tap thepotentialofalternativeop


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4 DesalinationResourceandguidancemanualtionsbeforedesalinationprojectsaredeveloped.

These include for example purification of low

quality localwaterandmeasurestoreducewa

terpollution,attainingamoreequitablealloca

tion of resources, and encouragingwastewater

recyclingandreuse.Desalinationmightafterall

haveashare insecuringwaterfordevelopment

andpoverty reductionwhen theaboveoptions

are being considered. One promising approach

for lessdeveloped countries is theuseof small

autonomous desalination systems powered by

renewable energy for decentralized water sup

plies,whichcouldmakeacontributiontopover

ty reduction in ruralareas.However, small sys

temsarenot in the focusof this report,which

addresseslargescaledesalinationprojects.

Costsandbenefitsofdesalinationin

comparisonwithalternativewatersupplies

Desalination canprovide a seeminglyunlimited

supplyofwater.Theoceanscontain97%ofthe

words water. Many coastal states and islands

havenootheroptionthandesalination,butthe

technologyalsohelpscountrieswith limited re

sources to meet the growing demand of their

populationsandeconomies.Desalinationcanbe

avitalneedorsupplementalcommodity.Itpro

videssafe,highqualitydrinkingwaterinanyde

siredquantity,andsafeguardsaconstantsupply

ofwatereveninthefaceofdraughtandclimate

change. Moreover, it can reduce pressures on

conventional resources,andmay thusavert se

vereenvironmentaldamagefromterrestrialand

freshwaterecosystems.

Despiteofferingmany socioeconomic,envi

ronmental andpublichealthbenefits,desalina

tion isnotgoing tobe theultimate solution to

the worlds water problems. It is more likely

going to remain one piece in the water man

agementpuzzle[4].Theeconomiccostsarestill

relativelyhighcomparedtowatersuppliesfrom

local ground or surface water resources. The

energydemandisalsoconsiderablesothatdesa

lination development may increase energy

dependence. Furthermore, concerns are raised

over potential negative environmental and so

cioeconomic impacts. These are mainly attri

buted to thedischarges to the sea,whichmay

impair coastal water quality and affect marine

life,andairpollutantemissionsassociatedwith

energy use, which may impair local air quality

and foil attempts to reduce greenhouse gas

emissions. Desalination may also lead to con

flictswithotherhumanorcommercialactivities

inthecoastalzone.

Thelistofpotentialimpactscanbeextended,

but the given examples already indicate the

needforanevaluationofthecostsandbenefits

of desalination projects in comparison with al

ternativewater supplyoptions.Nogeneral rec

ommendations can be provided in this regard.

Decisionsaboutdesalinationdevelopmentshave

to revolve around complex evaluations of local

circumstances such asdemand, financing,envi

ronmental and socioeconomic impacts [4].

Availablealternativesand theircostsandbene

fitsalsoneed tobe included in thisevaluation.

Forexample,thecontinueduseofcoastalaqui

fers may result in a significant increase in

groundwater salinity, or the transfers of water

fromariverorlakemayresultinsignificantand

irreversible damage to that ecosystem. In such

cases,theimpactsofconstructingandoperating

a desalination plant may be more acceptable

than the consequences resulting from the con

tinuationorexpansionoftheexitingoralterna

tivewatersupplypractices.

There seems to be little reason to object a

desalinationprojectwhenaclearneedhasbeen

establishedandwhenthe facility iscarefullyre

gulated and monitored. It is recommended to

conductafeasibilitystudyandanenvironmental

impactassessmentstudybeforeanewdesalina

tionproject isimplemented.Inordertoachieve

decisions in an open and transparent manner,

clear rules and standards for permission and

regulationofdesalinationprojectsshouldbede

veloped.Tothatend,thisreportoffersguidance

thatshallhelpregulators,projectdesignersand

decisionmakerstoanticipateandaddressallre

levant concerns thatmayarisewhenundertak

ing a desalination project, for obtaining maxi

mumbeneficialuseofthedesalinatedwater.


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Concept,methodologyandpracticeofenvironmentalimpactassessments(EIA) 5

A.1 DefinitionandconceptofEIAAnEIA isa systematicprocessused to identify,

evaluateandmitigatetheenvironmentaleffects

of a proposed project prior to major decisions

andcommitmentsbeingmade.Itusuallyadopts

abroaddefinitionof environment considering

socioeconomicaswellasenvironmentalhealth

effectsasanintegralpartoftheprocess.

ThemainobjectivesofEIAsaretoprovidein

formation on the environmental consequences

for decisionmaking, and to promote environ

mentally sound and sustainable development

through the identification of appropriate alter

natives andmitigationmeasures [5]. The three

centralelementsofanEIAare:

The establishment of environmental, socioeconomic, and public health baseline data

for the project site before construction. A

prognosis of the zero alternative is given,

which is the expected development of the

projectsitewithoutprojectrealization.

Thepredictionandevaluationofpotentialdirect and indirect environmental, socio

economic,andpublichealth impactsof the

proposedproject.

Theidentificationofappropriatealternativesandmitigationmeasurestoavoid,minimize,

remediate or compensate for any environ

mental, socioeconomic, and public health

impacts resulting directly or indirectly from

theproject.

In essence, an EIA of desalination projects is a

systematic process that examines the environ

mental, socioeconomic andhealth effectsdur

ingall lifecyclestagesoftheproject,i.e.during

construction, commissioning, operation, main

tenanceanddecommissioningoftheplant.

PartAConcept,methodologyandpracticeof

environmentalimpactassessments

applicableto

desalination

projects

A.2 SystematicEIAprocessfordesalinationprojects

TheEIAprocessisgenerallymarkedbythreema

jorphases(Figure2and3):

screeningandscopingoftheproject; environmentalimpactassessment; decisionmakingandEIAreview.In the following, a10 stepprocess isproposed

for conducting EIAs fordesalinationprojects. It

shouldbenotedthatinpractice,deviationsfrom

theoutlinedprocessmayoccur.Singlestepsmay

notalwaysbeclearly limitable,somestepsmay

overlapormaybe interchanged.TheEIAproce

dureshouldthusbeunderstoodasacontinuous

andflexibleprocess.


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6 DesalinationresourceandguidancemanualpreEIAstages

Projectproponents applicationforlicensetothecompetentauthority

Step1:Projectscreening

isafullfledgeEIArequiredfortheproject? mayfollowastandardizedorcustomizedapproach mayinvolveaninitialenvironmentalassessment

noEIArequired

EIArequired

public

involvement

Step2:Scopingoftheproject whatisthescopeandcontentoftheEIA? considerationofprojectalternatives preparationoftheTermsofReference(ToR)

Projectproponentsand/orconsultants prepareEIAaccordingtotheToR(Steps38)

mainEIAstagesStep3:Policy/administrativeaspects

whichpoliciesandregulationsapplyandwhichpermitsmustbeobtainedfortheproject?

considerationofEIAlawsandrequirementsandanyotherrelevantpoliciesandregulations

Step4:Projectdescription provisionofrelevantbackgroundinformationabout

theprojectwhichisrequiredtoevaluatethe

potentialimpactsoftheprojectontheenvironment

Step5:Baselinedata establishmentofenvironmental,socioeconomic andpublic

healthbaselinedatafortheprojectarea beforeconstruction

ofteninvolvesmonitoringactivitiesandsurveys

Step6:Evaluationofimpacts descriptionofallpotentialenvironmental,socioeconomic

andpublichealthimpactsandevaluationoftheirsignificance

Step7:Impactmitigation identificationofmeasuresinordertoprevent,minimizeor

remedysignificantadverseimpactstoacceptablelevels

Step8:Summary/conclusions summaryandconclusionsofthemainfindingsofsteps57 identificationofpreferredprojectconfiguration

Figure

2:

Pre

or

early

EIA

phases

(scoping

and

screening)

and

main

EIA

phase.


19/168


Figure3: EIAdecisionphaseandfollowupactivities.

Environmentalmanagement

effectsmonitoring:conductedduringconstructionandoperationinorderto

detectchangesthatareattributabletotheproject,usually

comparedtoreferencedataestablishedinbaselinemonitoring

compliancemonitoring:periodicmeasurementsofselectedparameterstoensurecompliance

withenvironmentalstandardsandregulations

evaluationofthepredictionsmadeintheEIA ifnecessary,correctiveactionssuchasadjustmentofimpactmitigationmeasures

Step10:

Review

&

decision

making

reviewoftheEIAprocessandEIAdocumentstoverifythecompletenessandqualityoftheEIA

approvalorrejectionoftheproposedproject impositionofimpactmitigationmeasuresandmonitoringactivities

Step9:Management/monitoringplanspecification ofmonitoring,surveillanceandauditingactivitiesduringconstructionandoperation

Projectproponents

construct,commissionandoperatefacilityredesignand

resubmit

finalEIAstages

postEIAstagesp

public

involvement

projectnot

approved

approved


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8 DesalinationresourceandguidancemanualA.2.1 Step1Screeningoftheproject

Screening is theprocessbywhich adecision is

takenonwhetherornotanEIAisrequiredfora

particularproject.ItshallensurethatafullEIAis

onlyperformedforprojectswithpotentiallysig

nificant adverse impacts or where impacts are

notsufficientlyknown.

Screeningthus involvesmakingapreliminary

determinationof theexpected impactofapro

posed project on the environment and of its

relative significance.A certain levelofbasic in

formationabouttheproposaland its location is

requiredforthispurpose.

The screening procedures can be broadly

classified into two approaches: a standardized

approach,inwhichprojectsaresubjecttoorex

emptfromEIAdefinedbylegislationandregula

tions;andacustomizedapproach,inwhichpro

jectsarescreenedonacasebycasebase,using

indicativeguidance[5].

Standardizedapproach

Many states have implemented EIA laws and

procedures,which facilitate thescreeningproc

essbydefining forwhich project categories an

EIAisrequired,suchas:

mandatoryor positive listswhich includeprojectsalwaysrequiringEIA(e.g.majorpro

jects,possibly largecogenerationplants for

electricityandwater);

projectlistswhichdefinethresholdsandcriteriaabovewhichEIA isrequired (e.g.ade

salinationplantlargerthan20,000m3/d);

exclusion or negative lists which specifythresholds and criteria below which EIA is

never required or belowwhich a simplified

EIA procedure applies (e.g. a desalination

unitwithlessthan500m3/dcapacity).

A class screeningmaybeundertaken for small

scaleprojects thatareroutineandreplicable, if

there is a reasonably sound knowledge of the

environmental effects and mitigation measures

arewellestablished.Forexample, class screen

ingcouldbeapplicable tosmallstandalonere

verseosmosis(RO)systemssuchasforhotels.

Theregulationsfordesalinationplantsmayvary

considerably indifferent states. If a categoriza

tion of projects in general or of desalination

plantsinparticularhasnotbeenundertaken,or

ifaproposeddesalinationproject isonthebor

derline of a threshold, theprojectneeds tobe

screenedonanacasebycasebasis.

Customizedapproach

Individualscreeningdoesnotnecessarilyrequire

additionalstudies,butcanbeconductedonthe

basis of indicative guidance, for example using

indicatorsandchecklists.Theseare intended to

beusedquicklybypeoplewiththequalifications

andexperiencetypicallyfoundincompetentau

thorities or environmental consultant compa

nies,basedon the informationwhich is readily

availableabouttheprojectanditsenvironment.

TheWorldBank[6]categorizationofprojects

mayallowafirst,broadscreeningofdesalination

plantsbasedona fewcommon indicators,such

asthetype,sizeandlocationoftheproject,en

vironmentalsensitivity,andlikelyhealthandso

cialeffectsonthelocalpopulation:

CategoryA:fullEIArequiredProjects likely to have significant adverse envi

ronmentalimpactsthatareserious(i.e.irrevers

ible,affectvulnerableethnicminorities, involve

involuntary resettlement,oraffect culturalher

itage sites), diverse, or unprecedented, or that

affectanareabroaderthanthesitesoffacilities

subject tophysicalworks (e.g.damsand reser

voirs, largescale industrial plants, ports, ther

mal andhydropowerdevelopments,etc.).

CategoryB:limitedEIAProjects likely to have adverse environmental

impacts that are less significant than those of

categoryA,meaning that few ifanyof the im

pactsare likely tobe irreversible, that theyare

sitespecific, and that mitigation measures can

be designed more readily than for category A

projects(e.g.smallscaleaquaculture,renewable

energy,ruralelectrification,watersupplyorsa

nitation, etc.). The main objective of a limited

EIAistoidentifysuitablemitigationmeasures.


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CategoryC:noEIAProjectsthatarelikelytohaveminimalornoad

verseenvironmentalimpacts.

A more elaborate approach is the use of com

prehensive

indicator

lists

or

checklists

for

screening. For example, two checklists have

beenpreparedbytheEUwithintheEIAdirective

framework1 to support the process of deciding

whetherornotaproject is likelytohavesignifi

canteffectsontheenvironment[7].

Thefirstscreeningchecklistprovidesa listof

questionsabouttheprojectanditsenvironment,

which shall help to answer the question if the

projectislikelytohaveasignificanteffectonthe

environment.The

second

checklist

provides

cri

teria thatshall facilitate theevaluationof signi

ficance. The checklists have been included in

Appendix D.1 for easy reference and slightly

modified to fit the specific conditions and re

quirementsofdesalinationfacilities.

There isnospecific rule thatcanbeused to

decidewhethertheresultsofascreeningcheck

listshould leadtoapositiveornegativescreen

ingdecision(i.e.thatEIAisorisnotrequired).As

ageneral

principle,

the

greater

the

number

of

positiveanswersandthegreaterthesignificance

oftheeffectsidentified,themorelikelyitisthat

anEIA isrequired.Uncertaintyabouttheoccur

renceorsignificanceofeffectsshouldalsopoint

towardsapositivescreeningdecisionastheEIA

process will help to resolve the uncertainty. If

theneedforEIAhasbeenaffirmed,scopingfol

lowsasthenextconsecutivestep.

PreliminaryEIAstudyInsomeEIAsystems,screening isconsideredas

a flexibleprocesswhichcanbeextended intoa

preliminary formofanEIA study (often termed

preliminaryorinitialenvironmentalassessment).

This is typically carried out in cases where the

environmental impactsofaproposalare largely

unknown,e.g.newtechnologiesorundeveloped

1

EIA

Directive

85/337/EEC

from

1985,

amended

by

Directive97/11/ECin1997.

areas[5].Ifapreliminaryassessmentisunderta

ken to assist in the screening decision, the in

formation from thepreliminaryassessmentcan

alsobeused for scopingand later in theactual

EIAprocess.Thesinglesteps inanEIAmaythus

notalways

be

clearly

limitable

and

some

overlap

mayoccur.

DocumentationofscreeningresultsAfter a formal decision has been made by the

competent authority, an official screening doc

ument is typically prepared which records the

screening decision and provides an explanatory

statement for thisdecision. Itmaybeextended

intoashortscreeningreportwhichalsogivesthe

resultsof

the

preliminary

assessment,

and

can

be used to prepare the scoping document for

publicdissemination in the followingstage.The

screening decision should be briefly outlined in

the EIA report, preferably in the introductory

section(cf.sectionB.3,p.22).

A.2.2 Step2ScopingoftheprojectScoping is the process of determining the con

tentand

extent

of

the

EIA

studies.

The

Terms

of

Reference (ToR), which are elaborated in the

process,provideclearinstructionstotheproject

proponenton the information thatneeds tobe

submitted to the competent authority for EIA,

andthestudiestobeundertakentocompilethat

information.

Scoping is a crucial step in EIA because it

identifies the issues of importance and elimi

nates thoseof little concern. In thisway, iten

suresthat

EIAs

are

focused

on

the

significant

ef

fectsanddonot involve unnecessary investiga

tionsthatwastetimeandresources.Theprocess

iscompletedwiththeToR,however,experience

shows that theToR shouldbe flexible andmay

needalterationas further informationbecomes

available,andnew issuesemergeorothersare

reducedinimportance[5].


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10 DesalinationresourceandguidancemanualConsiderationofalternatives

Theconsiderationofalternatives toaproposal,

suchasalternativetechnologiesorsites,isare

quirementofmanyEIAsystems.Itshouldbeun

derstoodasadynamicprocess,whichstartsear

ly inprojectplanningandcontinues throughout

the EIA process and decisionmaking. The pro

cess shouldbeopen tonew,emergingalterna

tiveswhilepreviously consideredoptionsmight

beabandonedduetonewinformationbecoming

available.Theaimistoidentifythebestpractic

able option under environmental, socioeco

nomic and human health criteria that is also

technicallyandeconomicallyfeasible.

Itshouldbenotedthatalternativestoapro

posal can be generated or refined most effec

tivelyintheearlystagesofprojectdevelopment.

The considerationof alternatives is therefore a

fundamentalpartof theearlyEIA stages,espe

ciallyof scoping.At this stage, anumberof al

ternativesistypicallyidentifiedforevaluationin

theEIA.Newalternativesmayalsobeidentified

lateron,especiallyatthestagewhenimpactmi

tigationmeasuresareelaborated.Itisimportant

that the considerationofalternativesduringan

EIAisnotreducedtoasuperficialandmeaning

less exercise. Thismay easily happen if project

planningadvances fasterthan theEIAanddeci

sionsforacertainprojectconfigurationor loca

tion have consolidated before the EIA process

hasbeencompleted.

Selectionoftheprojectsite

Environmental, socioeconomic and public

health impacts resulting from the construction

andoperationofadesalinationplantarelargely

dictatedbythelocationofthefacilityanditsas

sociated infrastructure. Therefore, proper site

selection for a desalination plant during the

planning process is essential for minimizing

theseimpacts.

Siteselectiontypicallytakesplaceintheearly

stagesofadesalinationprojectandleadstothe

identification of a preferred site and possibly

oneor twoalternatives.AnEIA,usuallyaccom

paniedbyasitespecificmonitoringprogramme,

will thenbe carriedout for the identified loca

tion(s). Inmanycases, thecompetentauthority

willgivepermissionbutattachconditionstopro

ject approval, such as to implement mitigation

measuresortomakechangesinprojectconfigu

ration, in order to minimize impacts on the

project site. In some cases, however, the EIA

mayalso come to the final conclusion that the

chosen site(s) are not suitable, even if impact

mitigationmeasuresareimplemented.

To reduce the likelihood of this outcome,

siteselectionshouldbeanimportantconsidera

tion inprojectplanning. Site selection can take

placeduringa preliminaryEIAstudyaspartof

thescreeningprocess(cf.Step1,p.9)orduring

scoping when the EIA requirements are deter

mined. To facilitate site selection for desalina

tion plants, public authorities may designate

suitableareas in regionaldevelopmentplansor

mayprovidecriteriathatcanbeusedbyproject

developers for siteselection. Selection of sites

must be carried out on a casebycase basis,

since there are a large number of sitespecific

considerationsthatvaryaccordingtothespecific

operationalaspectsofeachplant.

Generally, it is importanttoconsiderthefol

lowingsitefeatures:

Geologicconditions:Sites should provide stable geologic conditions

andlittleriskthatconstructionandoperationof

theplantwillaffectsoilandsedimentstability.

Biologicresources:Ecosystemsorhabitatsshouldbeavoidedwhere

possibleiftheyare

uniquewithinaregion(e.g.riffsonamainlysandyshoreline);

worthprotectingonaglobalscale(e.g.coralreefs,mangroves);

importantintermsofproductivityorbiodiversity;

inhabitedbyprotected, endangeredor rarespecies(eveniftemporarily);

important feeding grounds or reproductiveareas fora largernumberofspeciesorcer

tainkeyspecieswithinaregion;

importantforhumanfoodproduction.


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Oceanographicconditions:Thesiteshouldprovidesufficientcapacitytodi

luteanddispersethesaltconcentrateandtodi

lute, disperse and degrade any residual chemi

cals.Theloadandtransportcapacityofasitewill

primarily depend on water circulation and ex

changerateasafunctionofcurrents,tides,surf,

waterdepthandbottom/shorelinemorphology.

In general, exposed rocky or sandy shorelines

withstrongcurrentsandsurfmaybepreferred

overshallow,shelteredsiteswith limitedwater

exchange.Theoceanographicconditionswillde

terminetheexposuretimeoftheecosystemand

marine life to increased salinityandanypollut

antsdischargedalongwith thewastewater (cf.

sectionsC.4.4andC.4.5).

Rawwaterqualityandproximity:Theintakelocationshouldideallyprovideagood

and reliable water quality, taking seasonal

changes intoaccount,withminimumdangerof

pollution or contamination, in order to avoid

performance problems of the plant or impacts

onproductwaterquality.Theplant site should

ideally be close to the source water intake to

minimizelanduseforpipelinesandtoavoidpas

sage of pipes through agricultural land, settle

ments,etc.However,thiscannotbegeneralized

andinsomecasesitmaybemoreappropriateto

locate the plant further inland, for example

when constructionon the shore isnotpossible

forcertain reasons (e.g.useofbeaches,nature

reserves,geologicalinstability,etc.).

Proximitytowaterdistributioninfrastructure

and

consumers:

Thesiteshouldideallybeclosetoexistingdistri

bution networks and consumers to avoid con

structionandlanduseofpipelinesandpumping

efforts forwaterdistribution.However, impair

mentofnearbycommunities(i.e.consumers)by

visualeffects,noise,airpollutionorotherenvi

ronmentalhealthconcernsshouldbeavoided.

Vicinityofsupportinginfrastructure:Thesiteshouldalloweasyconnectionwithother

infrastructure, such as power grid, road and

communicationnetwork,ormayevenallowthe

couse of existing infrastructure, such as sea

waterintakesoroutfalls.

Conflictswithotherusesandactivities:Thesiteshould ideallyprovidenoconflictoras

littleaspossiblewithotherexistingorplanned

uses and activities, especially recreational and

commercial uses, shipping, or nature conserva

tionefforts.

Publicinvolvement

Publicparticipation isamandatoryrequirement

intheplanningand implementationofdevelop

ment projects, and an inherent component of

theEIAprocess,especiallyofscoping.Asagen

eralrule, thepublicshouldbe involvedasearly

aspossibleandcontinuouslythroughouttheEIA

process. The overall goal is the involvement of

the public in decisionmaking. This is based on

fundamental premises of democratic societies,

such as transparency of decisionmaking and

equityamongtheaffectedpopulations interms

ofethnicbackgroundandsocioeconomicstatus.

Publicinvolvementseeksto: inform the public about the project, the

value of the desalinated water and the ex

tent of the community investment, about

project alternatives including water conser

vationandrecycling;

gather a wide range of perceptions of theproposed desalination project and take ad

vantageoftheknowledgeofindigenousand

local communities about their living envi

ronment,therebyensuringthatimportantis

suesarenotoverlookedwhen theTermsof

ReferenceoftheEIAareprepared;

address and dispel if necessary subjectivedoubtsandconcernsabouttheproject;

develop trust and working relationshipsamong the stakeholders, including the af

fected communities, particularly vulnerable

groups, developers, planners, local and na

tional governments, decisionmakers, or

nongovernmentorganizations.


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12 Desalinationresourceandguidancemanual Important steps in the development of a

publicinvolvementprogrammeinclude:

identificationof thestages inprojectdevelopment and decisionmaking during which

publicinvolvementisrequired;

identification and categorization of the affectedpublicintostakeholdergroups,e.g.in

termsofdemographicorgeographiccharac

teristics (indigenousgroups, residents,etc.),

employment or work categories (fishermen

etc.),socialorinterestgroups;

anticipationofkeypublicparticipationissuesandquestionsrelatingtotheproject;

determinationofthenecessarylevelofpublicparticipation,which shouldbedoneata

level compatible with its relevance to the

proposedprojectandavailableresources

developmentofarealisticschedule,phasingandbudgetforpublicparticipation;

identification ofpublic participation and information mechanisms (e.g. press releases,

displaybooths, distribution ofbrochures or

newsletters,etc.)and informationgathering

mechanisms (e.g. public hearings, work

shops,opinionsurveys,telephonehotlines);

identificationofmethodsforinformationassimilation, analysis, record keeping and

documentation;

reportevaluationsandconclusions topolicyand decisionmakers, stakeholders, and the

public.

Examplesofpublicparticipationissuesare: sitespecificsensitivities:e.g.siteswithcer

tainreligiousandculturalsignificance;

historicalcontext:e.g.incidencesofnegativeenvironmentorpublichealthimpactsofcur

rentorearlyprojects;

politicalconsiderations:e.g.concernswiththeinfluenceofcertainindustries,orinterest

groups,andtheequityaspectsofbenefits

anddrawbacksoftheproposedproject;

publiceducation:e.g.informationofthepublicaboutbenefitsandpossibledraw

backsoftheproject;

conflictresolution:e.g.incertaincasespublicparticipationmayinvolvetheresolutionof

conflictsandthereachingofaconsensus

amonginterestgroupsconcerningthepro

posedproject.

Humanhealth

EIAs,aswidely requiredbynational legislations

andinternationalagencies,offerintegratedana

lyses ofpotential impacts of development pro

jectsonallcomponentsoftheenvironment, in

cluding human health. There has been recent

emphasis on the necessity to delineate the

health effects of environmental impacts (as

statedinthe2003EuropeanDirectives2andthe

ESPOOConventiononEIA3)ondirectlyor indi

rectly affected populations. When conducting

scoping for a desalination project, relevant hu

man health effects should therefore be identi

fied, considering the following recommenda

tions.

The human health component should be

broadly addressed in EIAs, relying on readily

available information. This includes community

health determinants, such as incidences of dis

ease,public informationand concerns,and tra

ditional knowledgeof the local inhabitants and

indigenouspopulation. Baseline information on

healthandqualityoflifeneedstobeestablished

inordertoassessthesignificanceofpotentialef

fects of environmental impacts. Potential envi

ronmentalhealth impactsshouldbeprioritized,

with corresponding indicators and risk factors.

Bothpositiveandnegativehealtheffectsshould

bedelineated, for thepublicat largeaswellas

forvulnerablegroups.

Wheretherearespecificconcernswithexpo

sure to certain toxic emissions or infectious

agents, the scientific literature should be

searchedforrelevantpublishedstudiesandepi

demiological investigations.This isusually suffi

cient to address concerns with the potential

healthimpact.MostEIAassessmentsrelyonex

istinginformation.Exceptforlargeprojects,itis

oftentooexpensive,andtootimeconsumingto

2EIADirective85/337/EECfrom1985,amendedby

Directive

97/11/EC

in

1997

3ConventiononEnvironmentalImpactAssessmentin

aTransboundaryContext(Espoo,1991)


25/168


generate new health information within the

timeframeallotted toconduct theEIA.Theme

thodology for theHumanHealth componentof

EIA is furtherdetailed insectionB.7.3. It isgen

erallybasedon:

screening and scoping steps to establish anexistingsetting;

assessmentofpotentialimpacts; reporting, mitigation and avoidance meas

ures,and

plansformonitoringactivities.Gendereffects

Gender mainstreaming is a globally accepted

strategyforpromotinggenderequality[8]4.The

UNEconomicandSocialCouncil (ECOSOC)5de

fined gendermainstreaming as the processof

assessing the implications for women and men

ofanyplannedaction,includinglegislation,poli

cies or programmes, in all areas and at all le

vels,so that womenandmenbenefitequally

andinequalityisnotperpetuated.

GenderImpactAssessment(GIA)hasbeenin

creasingly recognized as an adequate tool for

implementing gender mainstreaming in recent

years,especiallyinthewakeoftheFourthWorld

Conference on Women in Beijing in 1995. It is

usuallyappliedtopoliciesandprogrammes,and

means to compare and assess, according to

gender relevant criteria, the current situation

and trend with the expected development re

sulting from the introduction of the proposed

policy[9].

In the same manner as policies and pro

grammes may have a differential impact on

women and men, many development projects

will not be gender neutral. Genderspecific ef

fectsmaynotbeeasilyrecognizedatfirstglance,

butaneffortshouldbemadetoidentifyanysig

nificantdifferentialimpactsthatmayperpetuate

genderinequality.

Waterprojectsandthusdesalinationprojects

haveahighpotentialforgenderspecificeffects.

4

UN

Office

of

the

Special

Advisor

on

Gender

Issues

andAdvancementofWomen(OSAGI2001)5ECOSOCAgreedConclusions,1997/2

Women play a central part in the provision,

managementandsafeguardingofwater,which

isoneoffourrecognizedprinciplesoftheDublin

Statement on Water and Sustainable Develop

ment6. The consideration and integration of

genderspecific effects in EIAs for desalination

plants, fromscoping todecisionmaking, is thus

highlyrecommendedtoevaluatetheadvantages

and disadvantages of desalination activity on

both sexes.Where appropriate,adistinction in

the EIA process should be made between im

pactsonmenandwomen.Thedifferenteffects

maybeevaluatedforexampleinthechapteron

socioeconomic impacts (cf. B.7). It is recom

mended to outline the scope and approach of

howgendereffectsareaddressed in theEIA in

thebeginningofthereport(cf.B.4.4).

Scopingprocedure

Scopingproceduresmayvaryconsiderablyindif

ferent states. For example, scoping may either

be carriedoutunder a legal requirementoras

goodpractice inEIA,or itmayeitherbeunder

takenbythecompetentauthorityorbythepro

jectproponent[10].

It is recommended that the competent au

thority takes responsibilityat least formonitor

ingoftheprocess,forpreparingtheminutesand

official transcripts of the scoping meetings, for

keepingtherecordsofthescopingoutcome,and

for preparing the ToR. The scoping procedure

mayfollowthesefourgeneralsteps:

Based on the information collected duringscreening,a scopingdocument containinga

preliminary environmental analysis will be

prepared.Itwillspecifydetailsandproposed

location(s) of the project, review alterna

tives,brieflyandconciselydescribetheenvi

ronmental characteristics of the considered

site(s) and raise potentially significant pro

jectrelated issues. The scoping document

servesasabackgrounddocument forhear

ingsanddiscussionsduringscoping.

6

International

Conference

on

Water

and

the

Envi

ronment,Dublin1992,organizedbytheUNWorld

MeteorologicalOrganization(WMO)


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14 Desalinationresourceandguidancemanual The date and venue for the scoping meet

ing(s) will be set and a provisional agenda

prepared. Invitations for themeeting(s)and

the scoping document will be sent to col

laborating agencies, stakeholder groups,

NGOs,experts

and

advisers.

The

scoping

meetingwillalsobeannouncedinpublicand

the scoping document put on display for

public inspection. A handoutmay be circu

lated, notices posted in communities and

media advertisements arranged to enhance

publicparticipation.Ifthenumberofpoten

tially interestedpeople andorganizations is

large, questionnaires requesting written

commentsshouldbeconsidered.

Duringscopingconsultations,acompletelistof all issued concerns should be compiled.

Theseitemsmaythenbeevaluatedinterms

of theirrelative importanceandsignificance

toprepareashorter listofkey issues,which

canbe classified intodifferent impact cate

goriestobestudiedintheEIA.

TheTermsofReference forEIAwillbeprepared, including information requirements,

studyguidelines,methodologyandprotocols

forrevising

the

work.

ScopingtoolsandinstrumentsWhenacompetentauthorityoradeveloperun

dertakesscoping,threekeyquestionsshouldbe

answered[10]:

Whateffects could thisprojecthaveon theenvironment?

Whichoftheseeffectsarelikelytobesignificantandthereforeneedparticularattention

inthe

environmental

studies?

Which alternatives andmitigatingmeasuresoughttobeconsidered?

Basic instrumentssuchaschecklistsandmatric

es are often used to provide a systematic ap

proach to the analysis of potential interactions

betweenprojectandenvironment.

Forexample,checklistsforscopingareprovided

by theEUas supporting information to theEu

ropean EIA directive framework7. The scoping

checklists allow users to sift through a set of

project characteristics which could give rise to

significanteffects,

and

aset

of

environmental

characteristicswhichcouldbesusceptibletosig

nificantadverseeffects.

In order to evaluate significance, the same

checklistasprovidedforscreening(cf.Appendix

D.1) can be used. The scoping checklists have

been included in Appendix D.2 for easy refer

enceandhavebeenslightlymodifiedtosuitthe

purposeofthisdocument.

StandardizedscopingprocedureAn effective way of dealing with an increasing

numberofdesalinationprojectsmaybe toela

borate a standardized scoping procedure and

TermsofReference.Thescopingprocesswillof

ten involvethesamerepresentativesofgovern

mentagencies,NGOs,andconsultants.

Aguideline,elaborated inacollaborativeef

fortbetweenthesegroups,mayestablisharou

tine and set a standard for the environmental

studiesto

be

undertaken

and

the

information

to

besubmittedinEIAsfordesalinationplants.The

guideline could thus serve as a blueprint for

scoping, which should still allow for project

specificadjustments.

A.2.3 Step3Identificationanddescriptionofpolicyandadministrativeaspects

EIAsusuallytakeplacewithinthedistinctiveleg

islativeframeworks

established

by

individual

countries and/or international agencies. It is

therefore recommendable to gain a deeper in

sightandunderstandingofanynationalpolicies

or international agreements that apply in a

countryorregionandthatrelatetoEIA[5].

For instance, the first two steps of an EIA,

screening and scoping, shalldetermineif a full

7

EIA

Directive

85/337/EEC

from

1985,

amended

by

Directive97/11/ECin1997.


27/168


fledge EIA will be required for a proposed

project,andwhatthescopeandcontentsofthe

EIA will be. Existing EIA policies or regulations

shouldthereforebeconsultedastheywill likely

containrelevant information forresolving these

issues.

Moreover, any other policy relevant to the

desalinationprojectneeds tobe identified.Ma

jor thematic areas that should be considered

whensearchingthenationalor international le

galsystemforrelevantlawsinclude:

conservationofnature; biologicaldiversity; controlandpreventionofpollution; waterresourcesmanagement; landuseandregionalplanning.Inmanyjurisdictions,morethanonepermitwill

typically be required to realize a desalination

project. The main approval process, which au

thorizes construction and operation of a plant,

willnotnecessarily replaceotherexistingstatu

toryprovisionsandpermits.

For example, work place safety is an impor

tant consideration inall industrial facilities.The

construction

and

operation

of

a

desalination

plantcanpresentanumberofsafetyhazardsto

plantworkers,sothataspecificworkplacesafety

permit will probably be required and/or a plan

mustbedevelopedtoensureoccupationalsafe

tyandhealthoftheworkers.

Itisimportanttoclarifyearlyinprojectplan

ningwhichadditionalpermitsmustbeobtained

and to contact the competent authorities in

these regards. The permitting process may be

facilitatedby

nominating

alead

agency,

which

coordinatestheprocessbyinvolvingotheragen

cies and by informing the project proponent

aboutpermittingrequirements.

A chapter should be included in the EIA re

port,whichprovidesabriefdescriptionofallre

levantpolicies,agreements,plansorregulations

at regional, national and international level. It

should be stated how the project relates to

these lawsandthecompetentauthority ineach

area

should

be

named.

For

further

details,

pleasecf.tochapterB.5onp.23.

A.2.4 Step4Investigationanddescriptionoftheproposeddesalinationproject

A technical project description should be pre

pared and included in the EIA report. It should

formthe

basis

of

the

EIA

process

by

providing

background informationon theprojectwhich is

requiredto investigateandanalyzeallpotential

impacts.

Theprojectdescription shouldcover thedif

ferent lifecyclestagesofconstruction,commis

sioning,operation,maintenanceanddecommis

sioning of the desalination plant. It should be

succinct and contain all information necessary

forimpactassessmentbutomitirrelevantordis

tractingdetails.

For

further

guidance

on

what

to

includepleasecf.chapterB.6,p.27.

A.2.5 Step5Investigationandevaluationofenvironmentalbaseline

This step will entail assembling, evaluating and

presenting baseline data of the relevant envi

ronmental, socioeconomic and public health

characteristics of the project area before con

struction,including

any

other

existing

levels

of

degradationorpollution.

A nearby reference area with similar base

linecharacteristicsshouldbe identifiedandsur

veyed in addition to the project site. Results

from both the potentially affected and non

affected site can then be compared as part of

the monitoring process during construction,

commissioningandoperationoftheproject.The

mainpurposeofareferencesiteistodistinguish

between

changes

caused

by

the

desalination

projectandthosecausedbynaturalvariabilityor

otheranthropogenicactivitiesthatarenotattri

butedtothedesalinationproject.

The scope of the baseline studies to be un

dertaken in an EIA for a desalination project

shouldhavebeendeterminedduringthestepof

scoping(Step2)andshouldbebrieflyoutlinedin

theEIAreport(cf.B.4,p.22).Theywillprobably

have the following information requirements

(forfurther

details,

please

refer

to

chapters

B.7

toB.9).


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16 Desalinationresourceandguidancemanual Socioeconomicandculturalenvironment:Aspectssuchasdemographicchanges,landuse,

planneddevelopmentactivities, statusof exist

ing water resource management programmes

(conservationand reuse), community structure,

employment,distributionof income,goodsand

services, recreation, cultural properties, tribal

and indigenouspeople,customs,attitudes,per

ception,aspirationetc.

Publichealthenvironment:Healthindicesofthepopulationsatriskofbeing

affectedby theproject,e.g. ratesofmorbidity,

mortality, injuries, accidents, and life expect

ancy,aswellasrelevantsocioeconomic indica

torsofthequalityoflife.Itshouldbenotedhere

that WHO Constitution defines health as the

state of complete physical, mental, and social

wellbeing and not merely the absence of dis

easeorinfirmity.

Abioticenvironment:Aspects such as geology, topography, climate,

meteorology, ambient air quality, surface and

groundwaterqualityandhydrology,coastaland

marine environmental quality, existing sources

ofemissions toair, soilsandwater, capacityof

environmental systems to take up, degrade,

diluteanddisperseemissionsornoiselevels,etc.

Bioticenvironment:Aspects such as flora and fauna, including rare

andendangeredspecies,sensitivehabitats,spe

ciesofcommercialvalue,specieswithpotential

tobecomenuisances,alienspecies,etc.

A.2.6 Step6Investigationandevaluationofpotentialimpactsoftheproject

In this stepof theEIA,aprognosis,description

and evaluation of the potential environmental,

socioeconomic and health impacts of the pro

posed project is elaborated. Furthermore, the

magnitude, spatial and temporal range of all

identified impactsand theirrelativesignificance

shouldbeevaluatedat thisstage.Wherepossi

ble,anattempt shouldbemade to furtherdis

tinguish between direct and indirect impacts,

immediate and longterm impacts, reversible

andirreversibleimpacts,avoidableandunavoid

ableimpacts,positiveandnegativeimpacts.Itis

recommendedthatidentifiedpositiveandnega

tive effects are also balanced in terms of their

societalandenvironmentalcostsandbenefits.

Ifpossible,potentialcumulative,transbound

aryandgrowthinducingeffectsshouldbe iden

tifiedand investigated.This canbedone in the

individualchaptersoftheEIAreportdealingwith

socioeconomic, human health and environ

mentalimplicationsoftheproject(cf.B.7B.9),

while relevant aspects should also be pointed

outintheconcludingsection(B.10).

It is recommended to deliberate carefully

abouttheaccuracyofallpredictionsmadeinthe

EIA.Thesecanonlybeasaccurateandvalidas

the data and information available. It is there

forenecessary to identifyany informationgaps

anddeficienciesintheEIA,andtoassessanyun

certaintiesassociatedwith theprognosisof im

pacts.Aprecautionaryapproachshouldbepur

suedwhereuncertaintyaboutimpactsexists.

Methodsfor

predicting

impacts

AllpredictionsinanEIAarebasedonconceptual

models of the environmental systems. Several

approaches and instruments can be used for

predictingimpacts.Eachcoverstherangeofim

pactsonlypartiallyandshouldthereforebeused

inconjunctionwithothers.

Fieldandlaboratoryexperimentalmethods:This might include simple tests to predict im

pactsofacertainagentoractivityonan indica

tor (e.g.salinity toleranceortoxicitystudiesus

ingasensitivespeciesfromtheregion).

Physicalorimagemodels:This involves the design and construction of

small scalemodels to studyeffectswithahigh

degreeofcertaintyinminiature(e.g.aminiature

modelofadischargediffusersystemtestedina

laboratorysimulation).


29/168


Analoguemodels:Predictionsarebasedonanalogies, i.e.bycom

paringthepotentialimpactsoftheproposedde

salinationprojecttoasimilarexistingproject.

Mathematicalmodels:Models vary in complexity from simple input

output relationships to highly sophisticated dy

namic models with a wide range of interrela

tions, variables and coefficient constants that

havetobeidentifiedanddetermined.

Massbalancemodels:Thesemodelsarebasedonthedifferenceinthe

sumof the inputs as compared to the sumsof

outputs(e.g.

life

cycle

analyses).

Matrices:A two dimensional matrix is often used which

crossreferences the project activities on one

axiswiththeenvironmental,socioeconomicand

humanhealth setting in theproject siteon the

other axis.Thismethod allows fora systematic

identification and evaluation of causeeffect

relationships.

CriteriaforevaluatingsignificanceGeneralcriteriacanbeusedtoassessthesignifi

canceofenvironmentalandsocioeconomic im

pactsofadesalinationproject.Thesecriteriaare

notmutuallyexclusivebutareverymuch inter

related.Thefollowinggeneralcriteriashouldbe

taken into accountwhen examining potentially

significantadverseeffects:

natureofimpacts(direct/indirect,positive/negative,

cumulative,

transboundary);

timespan(short/medium/longterm,permanent/temporary,frequent/seldom);

extent(geographicalarea,sizeofaffectedpopulation/habitat/species);

magnitude(severe,reversible/irreversible); probability(high/medium/lowprobability) possibilitytomitigate,avoidoroffsetsignifi

cantadverseimpacts.

Furtherdetails

for

evaluating

the

significance

of

impactsaregiveninAppendixD.1.3.

A.2.7 Step7MitigationofnegativeeffectsThe considerationofmajoralternatives suchas

alternativelocation,technologyetc.shouldstart

earlyintheplanningofanewproject(cf.Step2)

asthe

flexibility

and

disposition

to

make

major

modificationsistypicallystillhighatthistime.As

project planning progresses and consolidates,

majoralternativeswillonlybe seriouslyconsid

ered if theEIAhas revealed significant impacts

(aspartofStep6)thatcannotbemitigatedoth

erwise. The investigation of impact mitigation

measuresshould thusbeunderstoodasaproc

ess,whichstartswiththeconsiderationofmajor

alternativesinearlyprojectplanningandcontin

uesafter

potential

impacts

have

been

analyzed.

Atthisstage,specificrecommendationsneedto

beelaboratedthatmitigatethepredictedeffects

oftheproject.

Thestepof impactmitigationshould identify

themostfeasibleandcosteffectivemeasuresto

avoid, minimize or remedy significant negative

impacts to levels acceptable to the regulatory

agenciesand theaffectedcommunity.Thedefi

nitionof acceptablewillvaryaccording todif

ferentnational,

regional

or

local

environmental

standards,whichdependonasociety'sorcom

munitys social, ideological and cultural values,

oneconomicpotentialsandonpolitics.

For impacts which cannot be mitigated by

technically and economically feasible methods,

compensation methods should be identified.

Documents

Resource Guidance for EIA