Field Study 4: Ithaka - Water Saving Islands

2017-09-13

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WATERSAVINGCHALLENGE

Christian Pleijel

[email protected]

Tel +358-457-342 88 25


FieldStudy4:Ithaka

Figure1.ViewfromOdysseus’hometowardsAfalesBayonNorthernIthaka

2017-09-13

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Christian Pleijel

[email protected]

Tel +358-457-342 88 25

Content1 Summary 2

2 Introduction 3

Theassignment

Theclient

Studyobjects

Thethreelevelsofanisland

Methodology

3 Thewateroftheisland 6

Location

Geology

Hydrologyandclimate

Vegetation

4 Thewateroftheislanders 9

Humanpressure

Virtualdistance

Waterconsumption

5 Thewaterofthecommunity 14

Governance

Waterprocurement

Wastewater

Waterquality

Costandtaxes

Futureplans

6 Watersaving 22

Benchmark#1

Benchmark#2

Benchmark#3

7 References 24

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1 SummaryIthaka is a 96km2islandwitharesidentpopulationof3,100.Technicallyspeaking,recal-culatingtheimpactofsummerresidentsandvisitors,thehumanpressureontheislandisequivalentto6,182all-yearinhabitants.

Thedemandforwatercanbeestimatedto247millionlitres/year,ofwhichisseemstheislandersuseofrainwatermeetsonethirdofthedemand.

Themunicipalityreallyhassomecreativewaystosavewater,mainlyabrilliantback-wardsbillingsystemandaflatratepolicyforgreenhotels(welldefined).

Theislandersarearolemodelforanyislandonhowtosaveanduserainwaterintheirhouseholds.

Fromawatersavingpointofview,IthakashouldcontinueseakingforleaksandchangesomeoftheolderACCmains(Vathi),andgetmorehotelstobecomegreen.

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FEL!DETGÅRINRTEATTHITTANÅGONREFERENSKÄLLA.

2 Introduction2.1 Theassignment

TheIthakastudyispartofanassignmenttosearchfor,find,describeandsharegoodex-amplesofwatersavingpracticesoneightEuropeanislands,islandswhodonotsolvewa-terscarcityjustbybringingmorewaterthroughpipelines,desalinationplantsandtank-ers,butaremakingeffortstosavewater.

Theprojectislookingforbestpracticeswithinfourareasofwatersavingactions:

1 Training:Information,goodexamples,schooling,campaigns,understandingthatwaterhasdifferentqualitieswhichcanbeusedfordifferentpurposes.

2 Engineering:Technologiesforreducingwaterconsumptioninhouseholds(watertaps,showerheads,toiletsinksetc),forreducingleakagesinmainsandpipes,formoreeffi-cientdesalination/reverseosmosisprocesses,treatmentofwastewateretc.

3 Billing:Differentiatedpricingof(municipal)waterthatleadtowatersaving.

4 Cutting:Switchingoffthe(municipal)water:mostlyforshorterperiodsoftime.

Obstaclestosavewatercanbefoundingovernance(watersavingisnotapoliticalissue),regulations,cost,taxesandfinancialobstacles(thewatercompanydoesnotearnmoneybysavingwater),no‘senseofurgency’,sustainabilityindicatorsareunderdevelopedorinexistent,management(savingisnotanobjective),humanbehaviour,businessthreats(watersavingmightruinthevisitors’experiencesanddamagetheisland’sbrand),tech-nologyandover-capacity(theislandhasasystemwhichprocuresmorewaterthantheislandneeds,eveninpeaks).

2.2 Theclient

TheassignmenthasbeengiventotheRoyalInstituteofTechnology(KTH)inStockholmbyMEPToninoPiculafromCroatia,theHellenicSmallIslandsNetwork,l'AssociationdesîlesduPonant,theIrishIslandsFederation/ComhdháilOileáinnahÉireannandESIN–theEuropeanSmallIslandsFederation..

2.3 Studyobjects

Eightislandsareincludedintheproject:TilosandIthacainGreece,LastovoandVisinCroatia,SeinandHouatinFrance,InisheerandCapeClearinIreland.

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Figure2.Theeightislandsinthestudy

Theyhavebeenchosenbecause(a)theyallhaveascarcityoffreshwater,(b)theyrepresentdifferentsizes,seas,hydrogeology,climate,sizeofpopulationandre-moteness,(c)theyhavewhatseemstobeinterestingsolutionsforsavingwater,and(d)theyhavebeeninpreviouscontactwithuswhichmakesiteasytoobtaintruedatawithinalimitedtimeandbudget.

2.4 Thethreelevelsofanisland

Tounderstandthefreshwatersituationofanisland,thewholeislandmustbeobserved(notjustthetechnologies).Wedescribethreeinterlinkedlevels:

a Thewateroftheisland

Thisisthebasicgeophysicalsystemlevelwhichencompassesthephysicalgeo-graphicalconditionsontheislandnomatterifpeoplelivethereornot:geology,oceans,skies,hydrology,meteorology,floraandfauna–thephysicallandscape.

b Thewateroftheislanders

Atthenextlevel,humansmoveinandmaketheirhumanfootprints:theybuildhousesandvillages,tillthesoilandwater,eat,drink,walk,arrangetheirsociallifewithchildren,schools,elderlycare,healthcareandsecurity–theculturallandscape.

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c Thewaterofthecommunity

Atthetoplevel,thehumansbuildacommoninfrastructureofroads,water,sewer,telephone,broadband,fossilandrenewableenergysources,portsandships.Waterisproduced,distributed,managed,financedandadministrated–thetechnicallandscape.

2.5 Methodology

Dataabouttheislandshasbeencollectedthroughdesktopresearchandfieldstudies,dur-ingwhichwemademakesemi-structuredinterviewswithpoliticians,techniciansandcitizens,investigatedtechnicalinstallations,tookpartofdocuments,plans,studies,mapsandearlierresearch.

ThisfieldstudyonIthakawasundertakenbyChristianPleijelandEleniPalaiolougkafromCRESonthe24th,25thand26thofMay,2017,undersupervisionofprofessorAndersNordströmfromtheUniverityofStockholmandprofessorSaraBorgströmatKTH.WearemostthankfultothetechnicaldirectorMrVasilisSimirisandthemayorofIthakaDioniosStanitsasfortheirtimeandeffortstoanswerourquestionsandguideusaroundtheis-land.

Figure3.DioniosStanitsas Figure4.VasilisSimiris

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3 Thewateroftheisland

3.1 Location

IthakaorIthaca(/ˈɪθəkə/;Greek:Ιθάκη,Ithakē[iˈθaci])isaGreekislandlocatedintheIonianSea,eastofthenortheastcoastofKefalonia,fromwhichitisseparatedbytheStraitofIthaca.

Theislandisabout96km2squarekilometres,stretchedinthenorth-southdirection,inlengthof23kmandmaximumwidthof6km.Itconsistsoftwoparts,ofaboutequalsize,connectedbythenarrowisthmusofAetos(Eagle),just600metreswide.ThetwopartsenclosethebayofMolos.

Figure5.Seachart,Ithaca

ThecapesintheislandincludeExogi,thewesternmost,Melissatothenorth,Mavronos,AgiosIlias,Schinous,SarakinikoandAgiosIoannis,totheeast,andAgiouAndreou,tothesouth.

BaysincludeAfalesBaytothenorthwest,FrikesandKioniBaystothenortheast,MolosGulftotheeast,andOrmosGulfandSarakinikoBaytothesoutheast.

ThetallestmountainisNiritointhenorthernpart(806m),followedbyMerovigli(669m)inthesouth.

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3.2 Geology

IthakalargelyconsistsofaseriesoffoldedJurassictoEocenelimestones.TheWesternsideisaridandsteep,theEasternsidegreenandaccessible.AsonKefalonia,thedomi-nanceoflimestonehasledtoalackofsurfacewater.

Figure6.GeologyoftheIonianIslands,Higgins&Higgins(1996)

3.3 Hydrologyandclimate

TheIonianislandshad1961-90anaverageyearlyrainfallof950mm(threetimestheav-eragerainfalloftheAegean).Theyaremountainousandbyfarthegreenestandmostfer-tileoftheGreekislands.mildMediterraneanclimatewithsunnyanddrysummers,mildandrainywinter.Extendedperiodsofsunshinethroughouttheyear.

Itrainsmainlyontheeasternpartoftheisland,asthewestsideisin"rainshadow"ofKefalonia.Thewinterprecipitationislarge,about600-700mmandallowsforalargegroundwaterformationintheeasternpartoftheisland.However,thelimestonemountainofferslimitedgroundwatermagazines.Mostofthewaterflowsrelativelyquicklytothesea

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unlesssealingbedrocklayersarevariedwithlimestone.Thewithdrawalopportunitiesmaybeaverageinsomeplacesforthesereasons.

Thegroundwaterareaisratherloweventhoughlargepartsoftheisland'slandsurfacearemuchabovesealevel.Thiscausesproblemswithgroundwateroutletsinwells,astheoutletsfurtherlowergroundwaterandthusincreasestheriskofwaterbecomingsalty.

3.4 Vegetation

Ithacaisbasicallytwowoodlandmountainridgesrichinfloraandfauna.Thelackofsur-facewatercoupledwiththescarcityofflatlandhasmadetheislandagriculturallyveryunproductive.

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4 ThewateroftheislandersThe3,100residentinhabitantsliveinsevenvillagesonIthaka.Vathyisthecapitalandlargestsettlementoftheisland(pop.1,920in2011)followedbyStavros(366),Perachori(343),Platreithias(201),andKioni(182).

4.1 Humanpressure

Ithakahas3,100all-yearinhabitants.Insummer(about10weeks),thepopulationthree-doublestomorethan9,000.Thereare10,000touristsontheislandduring45peakdaysinJulyandAugust.

Thehumanpressureontheislands'infrastructureincludingfreshwater,energydistribu-tion,sewageandwasterecuperationandtreatment,roads,ports,telephones,internet,transports,postalservices,healthcareandfirebrigade,canbecalculatedasfollows:

Residents 365days 3,100 1,131,500man-days

Summerresidents 90days 6,000 540,000man-days

Visitorspeakseason 45days 10,000 450,000man-days

VisitorsApril—Septexkl.peak 45days 2,500 112,500man-days

Visitorslowseason 90days 250 22,500man-days

Sumofman-days 2,256,500man-daysTable1:HumanpressureonIthaca

Thehumanpressureontheislandisthuswellover2millionman-days.Ifdividedby365days,itisequivalenttoaresidentpopulationof6,182inhabitants.

GiventheaveragewaterconsumptionofGreekpeople(115litresaccordingtoEurostat1),theislandwouldneed259millionlitres(260,000m3)offreshwaterperyear.

Thepressurefromhumansisveryuneven,peakinginsummerwhenwaterismostscarce.AhotdayinJuly,10,000visitorsplus6,000summerresidentsplus3,100all-yearresi-dentsareontheisland=19,100p/96km2=199p/km2.

1GeologyoftheIonianIslands,Higgins&Higgins(1996)

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Figure7.RainfallandhumanpressureonIthacapermonth(2016)

Thisdiagramisstillanestimate.

Figure8.IthakaWesternportPisoAetos

4.2 Remoteness

FromVathitoAstakosportonthemainland,thedistanceis35km.However,theferrydoesnotgofromVathibutfromPisoAetosontheWesternside,anditgoesviaSamionKefallonia.ThetravelingdistanceisthusxxkmgoingtoIthaka(fromAstakos),andyykmgoingfromIthaka(directlytoAstakos).

Theferrytakes3½hourstogetto/fromthemainland,whichmakestheperceivedorvir-tualdistancetoIthakamuchlargerthanthe”real”35kilometres.

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Beingdistant,Ithakahasdevelopedawaterprocurement(desalination/osmosis)systemofitsown,managesitssystemontheirown,hashighcostsfortechnicalgearandsupport,buildingmaterials,petrolandelectricity.Luckily,remoteGreekislandsreceivefinancialsupportforinvestments,see5.1Governancebelow.

4.3 Waterconsumption

CONSUMER’SPERSPECTIVE

InEurope,theaveragedailywaterconsump-tionratepercapitavariesbetween40and150litersperday.InGreece,itis115liters/personanddayaccordingtoEurostat2,whereof6litersforfoodanddrinking,35litersforbathandshower,15litersfordish-es,9litersforwashing,6litersforotherpurposesand17litersforflushingthetoilet.

Thedarkerthecolourofthewaterinthediagram,thelesspurifieddoesitneedtobe.Itisperfectlysoundtoflushyourtoiletswithrainwater(darkblue)butmanypeoplebuybot-tledwatertodrink(lightblue).

Fromearlierstudiesofsmallislandwaterconsumption3,itisreasonabletoassumethatresidentislandersuse75%ofthenationalaverage115litres/day,summerresidents100%ofthenationalaverage,andtourists(therearefewdaytouristsonIthaca,moststayaweek)usetheEuropeanaveragewhichis150litres/day.

Basedonthecalculationintable1,theyearlywaterconsumptiononIthakacanbeesti-matedto247,441m3:

Category Man-days Consumptionlitres/day

Totalconsumption

Residents(365days) 1,131,500 86 97,592m3

Summerresidents(90days) 540,000 115 62,100m3

2http://ec.europa.eu/eurostat/statistics-explained/index.php/File:To-

tal_freshwater_abstraction_by_public_water_supply,_2013_(m³_per_inhabitant)_YB16.png

3http://www.stromstad.se/byggaboochmiljo/vattenochavlopp/vakosteroarna.4.fc6ae6c153c5fdf8ad127e2.html

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Visitorspeakseason 450,000 150 67,500m3

VisitorsApril-Septexkl.peak 112,500 150 16,875m3

Visitorslowseason 22,500 150 3,375m3

Totalwaterdemand 2,256,500 247,442m3Table2:YearlywaterconsumptiononIthaca

Ofthese247millionlitresofwater,only17million(7%)isfordrinking,almost100mil-lionlitresisforshowersand50millionlitresisusedtoflushtoilets.

PRODUCER’SPERSPECTIVE

Lastyear(2016),theconsumptionofmunicipalwaterspring,wellsanddesalinationonIthakawas172,350m3freshwater4.

Category Totalconsumption

Households 2 114,179m3

Businesses(hotelsetc) 4 28,633m3

Semi-professionals 3 12,019m3

Municipalbuildings 0 131m3

Socialsecurity 1 2,457m3

Greenconsumption 5 142m3

Watertrucks 6,741m3

Hydrometerreplacement 466m3

Total 164,768m3Table3:YearlymunicipalwaterconsumptionpercategoryonIthaca

Dividedinto4-monthperiods,themunicipalwaterconsumedin2016was(watertrucksandhydrometerreplacementsnotincluded):

January–April 32,048m3

May–August 96,158m3

September-December 28,449m3

Total 156,655m3Table4:PeriodicalmunicipalwaterconsumptiononIthaca

4FiguresreportedbyMrSimiris26/5/2017

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Figure9:Waterconsumptioninthemunicipalsystem(2016)

A winter’s day, Ithaka needs 250 m3, a hot summer’s day when water consumption ispeaking,about1.000m3.

164,858m3is67percentoftheamountcalculatedfromtheconsumers’perspective(247,442m3),indicatingthattheislandsuseofrainwatermeetsonethirdofthedemand.

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5 Thewaterofthecommunity5.1 Governance

Ithaka is the second-smallest of seven main Ionian islands, after Paxi. Ithakaisasepa-rateregionalunitoftheIonianIslandsregion,andtheonlymunicipalityofthisregionalunit,createdoutofpartoftheformerKefaloniaandIthakaprefectureasapartofthe2011Kallikratisgovernmentreform.ThemunicipalityincludesisletsotherthanIthakabutonlyIthakaandAtokosarepopulatedislands.

Themunicipalitymanagesthewatersupply,storageanddistributionthemselves.

InvestmentscanbesupportedfromtheMinistry,fromtheEuropeanUnionregionalfunds,orfromthePublicDeposit/Fundcreatedmainlytofundmunicipalinvestmentsatalowinterest(3-4percent).AproblemisthelowcompetenceontheislandwhenitcomestoapplyforMinisterialand/orEuropeanfunding.

5.2 Waterprocurement

Theislandsfreshwatercomesfromfourdesalinationplantsinthreepremises,onewellandonespring.

DESALINATIONPLANTS

1

InDexa,aJUDOdesalinationplantfrom2005produces200m3/d.Itswaterispumpedtoa100m3reservoirintheStavrosvillage.

In2016,theplantproduced46,772m3.

Sincethewaterproducedbytheplantisnotenough,thevillagesonlyhavepermissiontowater2days(MondayandThursday)perweekfromJuly20toSeptember15.

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2

InKioni,aJUDOreverseosmosisplantproduces120m3/dwhichisstoredina300m3anda600m3tankonthemountainabovethevillage.

In2016,theplantproduced19,587m3.3

Making57,7m3/h Dexaplant’ssaltwaterintake

InDexajustnorthofVathytherearetwo500m3/dJUDOwaterdesalinationplants.Waterispumpedto2x3,500m3tanksfrom1953justsouthwestofthevillage,fromwhichpipesgotoPerachori,towesternVathy,andtoeasternVathyviaapumpstation(“booster”)andtwo800m3reservoirsfromthe1970’s.

Osmosisisbasedontheuseofexternalpressuretoallowwatermoleculestoflowthroughasemipermeablemembrane;Asaresult,theionsremainononesideofthemembrane,whilethewatermoleculespassthroughit.Oneovercomestheosmoticpressure.

3m3ofseawaterisusedtoproduce1m3offreshwater.

Themethodcanbeusedtopurifyseawatertodrinkingwater.However,energyisneededtoachievetheexternalpressure,whichiswhyitisanexpensivemethodofproducingdrinkingwater–thoughbetterthanothermethodsifnothingbutseawaterisavailableinsufficientquantities.

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Desalinationisalsoanenergyhog:desalinationplantsaroundtheworldconsumemorethan200millionkilowatt-hourseachday(300millionpeoplegetfreshwaterfrommorethan17,000desalinationplantsin150countries5).Energycostsareestimatedat55per-centofaplants’totaloperationandmaintenancecosts.Ittakesmostreverseosmosisplants3to10kWhofenergytoproduceonecubicmeteroffreshwaterfromseawater.Traditionaldrinkingwatertreatmentplantstypicallyusewellunder1kWhperm3.

Duringthisfieldstudyitwasstillunclearmuchenergyisusedinthedesalinationprocess-es.239,548m3ofdesalinatedwaterwasproducedduring2016.GiventhataJUDOplantneeds5kWhtoproduce1m3,itwouldtake1,200MWhtoproduce114,000m3.If10kWh/m3isneeded(moreprobable),theamountofenergyconsumedtoproducethewaterisabout2,400MWh.

WELLSANDSPRINGS

TheLefkiwellsituatedis200metersdeep,giving1,4m3anhourbuthasahighpercentofsalt.

Waterispumpedina100m3tankabovethewellandledthrough1,500meterofhosesconnectthehousesinthevillage,whichareanoff-gridsystem.

ThespringatKalamosproduced4,613m3peryear.

Thewateriscollectedina15m3cisternbehindthespring,pumpedtoa37m3res-ervoirabovethespringandthenfedgravi-tallytothevillageofPlathreitosandtotwocisternsclosetoLimneschurch.

ThePerachoridrillno1is249metersdeep,giving2,5m3anhourbuthasahighrangeofpercentofsalt(conductance1.500-3.200μS/cm).Thesystemalsoworkswithatimerforthenon-exhaustionoftheaquifer.Thedrillingwaterisdraineddirectlyintothevillage'sgrid.Itstaysbystandincaseofemergency.

ThePerachoridrillno2is185metersdeep,giving1,5m3anhourbuthasahigh

TheStavrosdrillis217metersdeep,giving1,5m3anhourandthewaterisdrinkable

5https://www.pri.org/stories/2015-05-15/desalination-expensive-energy-hog-improvements-are-way

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rangeofpercentofsalt(conductance2.500-3.500μS/cm).Thesystemalsoworkswithatimerforthenon-exhaustionoftheaquifer.Thedrillingwaterisdraineddirectlyintoavillage'scistern.Itstaysbystandincaseofemergency.

ThetotalproductionofPerachoriareafortheyear2016was25.676m3.

(conductance750μS/cm).Thesystemalsoworkswithatimerforthenon-exhaustionoftheaquifer.Thedrillingwaterisstoredtotankstoenhancethewaterstockofthevillages.

TheAg.SpiridonasandPanagouspringswestofVathihaveanaverageannualpro-duction26.000m³and3.500m³ofdrinkingwater.BuiltduringtheBritishoccupationaround1800.Waterisfedthroughgravitytoreservoirstostrengthenthereserves.

TheAretousaspringislocatedinSouthIthacainMarathiasawayfromvillages.Thewaterisdrinkable,runningallyearroundbutinasmallamountanditisnotused.

RESERVOIRS

Figure10.TheEnglishreservoirfrom1850

Therearethirteenmunicipalwaterreservoirs:

1 Lefki 100m3

2 Stavros 100m3

3-4 Kalamos 15m3+30m3

5-6 AgiiSaranta xxm3+yym3

7-8 Kioni 300m3+600m3

9 Soutras

10 VathyNW 1.000m3(Englishtankfrom1850’snotinuse)

11 VathySouth 3.500m3+3.500m3

12-13 VathyEast 800m3+800m3

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Thewaterinthereservoirscovers70%ofthewinterconsumption.ThedesalinationplantsareatworkfromMayuntilOctober,butstilldonotmeetthetotalconsumptionneedswhichiswhytherearefrequentwatersupplyinterruptions.

RAINWATERCOLLECTION

Themunicipalityhasfournon-functioningrainwatercollectors:Kioni,VathyNorthWest,VathySouthandVathyEast.Thereasonfornotbeinginuseisthathavebeenbrokenbyearthquakesanditisdifficult/impossibletorepairthem.

DISTRIBUTION

Therearethreeindependentwaternetworksontheisland:TheVathi-Perachorinetwork,

theStavrosnetworkandtheKioninetwork.

Figure11.TheVathi-Perachorinetwork

Figure12.TheStavrosnetwork

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Figure13.TheKioninetwork

Pipesaremadeofpressedplastic(notPVC),6meterseach,gluedtogetherandsometimesfittedwithalock,dimension125/140or42/50mm????Someofthepipes(Vathi)are

madeof/linedwithasbest.

TheLefkivillageisn’tconnectedtothewaternetworkandtakeswaterfromadrilling(de-scribedonparagraph5.3.2).Thetankfeeds7commonvalvesinthevillagethatprovide

thehousecisternswithwaterthroughpipes(tires).Thewatersupplyismadebyamunic-

ipaltechnicianwhounlocksthevalveandcountsthewaterthat"pulls"thehouse.

Figure14.VanesinthevillafeofLefki

AnogiandExogiaretwovillagesthatarenotconnectedtothewaternetwork.Thehouseshavecisternsoraresuppliedwithwaterbywatertrucks.

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Figure15.Watertruck

5.4 Wastewater

Thereisnosewagenetwork,nowastewatertreatmentplantandnosanitarylandfill(thereisnosuitablelocation).ThereareveryhighcostfortransportingMSWtothesanitarylandfillinKefalonia,thereisnorecyclingorcomposting.Nexttowater,wasteistheis-land’sbiggestchallenge.

5.5 Shortageandqualityaspects

During2016,itseemsabout42percentofthefreshwaterwaslostinleakages.InPeracho-ri,44percentofthewaterwaslostbutfouroftheleakswereearlierfoundwithasounddetector(Aquaphon),whichnowhasbeenoutoforderforalongperiodandsubsequentlyhaspreventedthemunicipalityservicefromdetectingnewnetworkleaks.Fortheyear2016thefollowingleakageratesweremeasured:

Perachori 44% 4leaksrepaired

Vathi 39% 2leaksrepaired,1moreexists

StavrosPlatrithias 40% 3leaksrepaired,1moreexists

Kioni 18%

Total 35% Table5:Leakages2016

5.6 Costsandtaxes

Thetotalcostextracting,producing,distributingandadministratingwateronIthakacoststhemunicipality400,000€peryear.

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Thecostiscoveredbybillingtheconsumers280,000€andbya120,000€supportfromtheMinistry,whichispartoftheGovernmentsaidtoislandswhoareoff-gridandareforcedtousedesalinationtechniques.

280,000€billedtotheconsumersfor172,350m3indicateapriceofabout1,62€/m3.

5.7 Futureplans

Ithakaswaterdepartmenthasthefollowing‘wishlist’:

1 RenovatetheEnglishreservoir(an90,000€investment)

2 Twonewdesalinationsplants,oneinVathi(500m3),oneinStavros(200m3)

3 NewwatermainsinVathi

No2and3areaninvestmentofabout15millioneuro

4 Moregreenbuildings(likeHotelNostos)

5 Continuethesearchforleakages

6 Morebackwardsbilling

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6 Watersaving

6.1 Benchmark#1:Thelesswateryouuse,thelessyoupayperm3

ThemunicipalityBoardhasdecidedtohaveabackwardsbillingsystemtopromotesavingwater:ifahouseholduses0-40m3per4months,youpay1€/m3;ifyouuse41-80m3per4monthsyoupay1,30€/m3;ifyouuse81-120m3per4months,thepriceis1,50€/m3;ifyouuse121-160m3per4months,thepriceis2€/m3;andfinally,ifyouusemorethan501m3per4monthsyoupay3€/m3.

Thesamegoesforbusinesses(category4,i.e.hotels)butwithslightlydifferentnumbersandprices:ifthehoteluses0-150m3per4months,theypay2€/m3;iftheyuse151-300m3per4months,theypay3€/m3;iftheyuse301-500m3per4months,thepriceis15€/m3;andiftheyusemorethan501m3per4monthstheypay6€/m3.

Thereisalsoasemi-professionalcategory(3).Iftheyuse0-50m3per4months,theypay1,60€/m3;iftheyuse51-150m3per4monthstheypay2,00€/m3;iftheyuse151-200m3per4months,thepriceis2,50€/m3;iftheyuse201-250m3per4months,thepriceis3€/m3;andfinally,iftheyusemorethan251m3per4monthstheypay5€/m3.

Simplyput:ifyouuselesswater,youpaylessperm3.Youmightsaytheynotonlyusere-versedosmosisbutalso“reversedeconomiesofscale”.

Figure16.ThemunicipalgreenpolicyandtheexteriorofhotelNostos.

6.2 Benchmark#2:Amunicipalpolicyforgreenhotels

Thereisamunicipalpolicyforhotelsthat“gogreen”:iftheymeetasetofwater-savingcriteriaasdefinedbyamunicipalityboardin2009,theypayaflatrateof1€/m3forwater.WevisitedNostosHotel,whichusesslightlysaltwaterfromawelltoflushthetoiletsinthehotelrooms,rainwaterforthepool,andmunicipalwaterfortherest.Thehotelguestknewnothingofthisandwerehappylikefishinthesea.

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6.3 Benchmark#3:Privaterainwateruse

IslandersonIthakacollectrainwaterandstoreitintankstypicallyundertheirhouses.Itisestimatedthat90%oftheactivedwellingshavecisterns20-150m3.

FromahouseinPerachorivillage,wewereabletospotfourwatercisterns:

Figure11.PrivatewatercisternsonIthaca

Asstatedinpart4.3above,itseemsthemunicipalityproduces67%(164,858m3)ofthetotalyearlyamountofwaterneededonIthaka(247,442m3),indicatingthattheislandsuseofrainwatermeetsonethirdofthedemand.Thisisanexcellentwayofsavingwater.

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7 References

HigginsMD,HigginsR:AGeologicalcompaniontoGreeceandtheAegean(1996)

Eurostat:http://ec.europa.eu/eurostat/statistics-explained/index.php/File:To-tal_freshwater_abstraction_by_public_water_supply,_2013_(m³_per_inhabitant)_YB16.png

InterviewswithTechnicalManagerVasilisSimiris,technicaldocumentation

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Field Study 4: Ithaka - Water Saving Islands

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Transcript of Field Study 4: Ithaka - Water Saving Islands