P oceedings
J,ne21-2612010
SWI M21
Azo es·
Po ugal
21s
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In usion
Mee ing
O igino  heg oundwa e saliniza ioninLaAldeacoas alaqui e 
(G anCana ia,Cana yIslands)
T.C uz1,M.C.Cab e a1andJ.He edia2

1[email p o ec ed]&mca[email p o ec ed]
Depa men o Physics,Uni e si yo LasPalmasdeG anCana ia,35017
LasPalmasdeG anCana ia(Spain)
2[email p o ec ed]
GeologicalSu eyo Spain,RíosRosas,23.28003Mad id(Spain)
ABSTRACT
G oundwa e chemis yinLaAldeaaqui e (G anCana ia,Cana yIslands)showshigh
con en so chlo ideandni a eions.Thesaliniza ionp ocesshasbeenmodelledusing
hegeochemicalda a, akingin oaccoun  he esul so ap e ious lowmodel.The
esul sallow oiden i y hesalini yo  he echa ge om he ain allunde a idi y
condi ionsand hei iga ion e u nslike hemaincauseso  heg oundwa e 
saliniza ion.
INTRODUCTION
LaAldea a ine,loca edon hewes e nsideo G anCana ia(Cana yIslands,Spain),p esen sa
la bo omsu oundedbyhighmoun ains(wi hheigh s a ying omseale el o1,415m).The
clima eisd ysub opicalwi hhigh empe a u es h oughou  heyea .In ensi eg eenhouse
ho icul u e(mainly oma oesandcucumbe s)isp ac icedwi hacul i a ionsu aceo 645ha
andi iga ionwa e ismainlysuppliedby h eedamssi ua edups eam,al houghmo e han
370la ge‐diame e wellsalsop o idec opwa e  equi emen sin hed yseasons,diminishing
hequali yo g oundwa e .

Thegeologyo  hea eashowsasedimen a yuni ,he e ogeneous,composedo allu ialand
sc eesdeposi s(consis ingo de i icalma e ialwi hphonoli es‐ achy es,ignimb i esand
basal sboulde s)anda olcanicuni ,alsohe e ogeneous,consis ingo Miocenebasal sloca ed
benea h hesedimen a yuni andoccupies heen i esu acewi halowe pe meabili y han
heallu ialdeposi s(Figu e1).The eisa esidual elie loca edeas o  hes udya eabe ween
Fu elandLaAldea a ines(LasTabladas)wi hacomplexgeology,whe eslidhyd o he mal
deposi s(Azulejos)c opsou .

G oundwa e  lowsmainly h oughallu ialma e ials omeas  owes along heLaaldea
allu ial, ha  ep esen sadischa gea ea om heaqui e  o hesea.The eisalsoanimpo an 
low ommoun ainousa easloca edno handsou h owa ds heLaAldeaallu ial.Wa e 
balancehasbeendone o  hehyd ologicalyea s1991‐1999(C uz,2008)andshows ha  he
echa geisa esul o i iga ion e u ns(60%)and ain all(20%).

Thehyd ogeochemis yo  hea eahasbeens udiedsince1992du ingse e al esea chp ojec s
ino de  oquali a i elycha ac e izeLaAldeaaqui e (Muñoze al.,1996;Muñoz,2005;C uz;
2008).Thehyd ogeochemicalconcep ualmodelwases ablishedandsugges s ha awa e  low
ombasal s o heallu ialexis s,and he e o e heex ac edwa e  ep esen amixingo wa e 
ombo huni s.
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G oundwa e in hea eap esen shighsalini y a ios(Clcon en sup o7000mg∙L‐1andN
con en sup o700mg∙L‐1)insomeplaces,and heo igino salini yis heaimo  hep esen 
communica ion.



Figu e1.Localiza iono LaAldeaaqui e inG anCana ia(Cana yIsland,Spain)andgeologicmap
showing hemaingeologicaluni s.

METHODS
In hiswo k, hespa ialand empo aldis ibu iono chlo ideandni a eionsandchemical
cha ac e is icso  hedi e en sou ceso  echa geha ebeens udied oquan i y hein luence
o  hedi e en sou ceso salini y(mainlysalini yo  ain alldue oa idi yandi iga ion
e u ns).Theaqui e salini yhasbeenmodeledalonga lowline(wi h h ee ep esen a i e
wells)in heaqui e (Figu e1)usingPHREEQC.Themodelhassimula edmixingp ocesses
be ween echa gewa e ( ainandi iga ion e u ns)andg oundwa e andchemical eac ions
ha occu insoiland ocksindi e en a easo  heaqui e .

RESULTS
Figu e2shows hespa ialand empo ale olu iono chlo ide o  heyea s1992and1999.The
highes concen a ionsa eobse edinLasTabladas oo and esul s om heleachingo  he
Azulejos.Thelowe concen a ionswe e oundin heMiocenebasal sin hehighes le els.In
gene al, he eiscoincidencebe ween hedi ec iono g oundwa e  lowand heinc easein
chlo ideconcen a ion.Compa ingbo hyea s,aninc easeinchlo ideconcen a ionsis
obse ed.Thea e ageconcen a iono chlo idein hes udya eais711mg∙L‐1 o 1992and
1110mg∙L‐1 o 1999.

Thea e ageconcen a iono ni a esis88mg∙L‐1 o 1992and175mg∙L‐1 o 1999which
ep esen sasubs an ialinc easein heconcen a ion o  his imepe iod, eachingmaximum
alueso 484mg∙L‐1 o 1992and708mg∙L‐11999.Figu e2shows hespa ialand empo al
e olu iono ni a eionshowing ha maximum aluesa eloca eda  hemou ho  he
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Tocodomán a ineand hesou he no LaAldea a inein1992andin1999high alueso 
ni a esoccupymos o  heallu ialloca ed ha iswhe emos c opsa eloca ed.




Figu e2.Isoconcen a iono chlo ideandni a e o 1992and1999.

DISCUSSIONANDCONCLUSIONS
Di e en hyd ogeochemicalp ocesses ha con olg oundwa e geochemis yha ebeen
iden i iedandquan i ied.Rainwa e  ep esen s he20%o  echa ge ha joins heaqui e wi h
ex asaliniza iondue osalini yo  he echa ge om he ain allunde a idi ycondi ions
(Cus odio,1993).I iga ion e u ns ep esen s60%o  he echa geandcausesinc easedsalini y
due o hehighe apo anspi a ion a es.Finally,o he geologicalinpu o highsalini ywa e sis
loca eda LasTabladashasbeena ibu ed oleachingo  hedeposi sknownasAzulejos.

Chlo ideconcen a ionin ainwa e  anges om30mg∙L‐1and450mg∙L‐1ina eas a he and
nea e  hesea espec i ely(Munoz,2005;Alcala,2005,C uz2008).Rainwa e e apo a ionhas
beencalcula edbe ween60%and70%(C uz,2008)p oducinganinc easein hesalini yo  he
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echa ge.I iga ion e u nswa e sha eani a econcen a iono mo e han650mg∙L‐1(C uz,
2008)TheAzulejosin luencehasbeens udied om hechemis yo someoozesloca edinLas
Tabladaswi hwa e s ha ha echlo ideconcen a ionso mo e han8000mg∙L‐1andni a e
concen a ionabo e500mg∙L‐1.

Themodelinghasbeenca iedou  ep oducing hechlo ideandni a econcen a ionin wo
wellsloca edin hemiddleandlowpa o LaAldea a ine(0779‐TPand0218‐O1, espec i ely)
om hewellwa e 2714‐TPloca eda heade (Figu e1)assuming ha allni a ecomes om
i iga ion e u nsandchlo ide echa geby ain all.Thes udyo  hechemicale olu iono 
g oundwa e in he lowline(2714‐TP o0779‐TPand2714‐TP o0218‐O1)shows ha  hewell
0779‐TPp esen s2%o ma inewa e  espec  o2714‐TPand hewell0218‐O1p esen s4%o 
ma inein luence espec  o2714‐TP.Thismeansama inecon ibu iono 0.5%pe kmin he
lowline o 0779‐TP, anging o0.7% o 0218‐O1.Thisinc easein he a eo ma inesp ay
con ibu iono 0.2%in0218‐TPsha wi h espec  o hewell0779‐TPimpliesaninc easein he
con ibu ionasweapp oached hecoas ,whichalsocon i m ain allchemicalda a.

A ending o hemodel esul s, heg oundwa e  ecei es51%o i iga ion e u nsin hewell
0779‐TPand89%in hewell0218‐O1.Thisdemons a es heimpo anceo i iga ion e u ns
wa e asinpu  o hesys emandasasou ceo con amina iono g oundwa e andcon i ms
ha g oundwa e p esen smo ein luenceo i iga ion e u nsasmo ingin hedi ec iono 
low.

REFERENCES
Alcalá,F.J.2005.Reca gadelosacuí e osespañolesmedian ebalancehid ogeoquímico.Doc o al
Thesis.TechnicalUni e si yo Ca alonia.
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C uzT.,2008.Con ibucióndelamodelaciónnumé icaehid oquímicaalconocimien odelacuí e o
deLaAldea(G anCana ia,IslasCana ias).Doc o alThesisUni e si yo LasPalmasdeG an
Cana ia.
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Cus odio,E.,1993.Coas alaqui e saliniza ionasaconsequenceo a idi y: hecaseo Amu ga
phonoli icmassi ,G anCana iaIsland.InE.Cus odioandA.Galo é(eds.):S udyand
modelingo sal wa e in usionin oAqui e s.Ed.CIHS/CIMNE,Ba celona,81‐98.

Muñoz,J.,2005.Funcionamien ohid ogeológicodelAcuí e odeLaAldea(G anCana ia).Doc o al
ThesisUni e si yo LasPalmasdeG anCana ia.

Muñoz,R.,Cab e a,M.C.,He nández,F.andSoco o,A.R.1996.De elopmen o Analy icaland
SamplingMe hods o P io i yPes icidesandRele an T ans o ma ionP oduc sinAqui e s.
FinalP ojec Repo .

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Con ac In o ma ion:Ta ianaC uz,Uni e si yo LasPalmasdeG anCana ia.Depa men o 
Physics,Uni e si yo LasPalmasdeG anCana ia,35017LasPalmasdeG anCana ia(Spain),Phone:
+34928458080,Fax:+34928452922,Email:[email p o ec ed]

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