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Hydrologic Behavior C)f Unsaturated, Fractured Tuff: Interpretation and Modeling of a Wellbore Injection Test and Implications for Contaminant Transport Urun· A. Rohin!>on •

Earth and En\lironmcntal S~.:icn~cs (Jivisinn LAIS Alamus National Lah,•ratory

l"'" Alamos, 1\cw Mexico

Stephen Ci. McLin Environment Safety and Health Div1sinn

Lo~ Alamos National Laboratory l..tls Alamos. New Mexico

Gilles Y. Bus sud Eanh and Environmental Sc•cnce!. Division

Los Alamos National Lahnratory Los Alamos. New Mexico

M<ty 16.2001

•Comsponding author (505 1 M7-1910. Fax !50~) 665-8737. rohinson(!tlanl.g<W

Abstract

An injeclinn mnc te!'t in the Tshirc~c Mcmhcr of the Bandelier tuff reported hy Purtymun et al. ( 1989) has ~n interpreted and ITl<ldcled using a continuum model that considers only matrix tlow. The at.'Teemcnt of tiM: nurncrical•no~olcl and the data W<ts quite acccptahle. hoth qualitatively and quantitatively. The migration of moisrurc injl'Cted in an open interval uf the wellhorc c}lhihitcd flow that was controlled by both gravity and capallary forces. In addition to qualitative agrcemem with moisture cross sections constructed from neutron log data. the model provided an adequate match to data on the rates of migration of the water plume in the vcnical (upward and downward) and lateral directions. Although more complex model formulations are possible. the continuum model is demonstrated to reproduce the injection data. and therefore is to be favored due to its simpler formulation and case with which it is implemented in large­scale flow and transpon simulations. Since matrix-dominated llow is observed at the high effective infiltration rates of this injection test. then it is even more likely to he the case under natural conditions on the Pajarito Plateau. the l<x:ation of Los Alamos National Lahonttory 1 LANL). Addit10nal field scale monitoring and site characterilation cffons arc rcquin·d to extend the results to solute transpon, so that calibrated mcdd!> can he u!\ed reliably to predict the transpon of contaminants introduced to the groundwater from pa."it LANL operations.

Keywords: Un'lltUratcd nuw: fructun:d tuff; tluid injection l(·~t: groundwater modeling

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Introduction

l.o, t\1;1111<" r.;;~IJ.,n;all..ah~tratmy d A !"'Il.. or lh~· I ahorailrr~ 1 Ita~ perlonrll'd ll'''~·''' h ;m.! .tcvdopm,·nt 111 nudeotr v.t'JPIII" ll·,·hnologat'' otnd nthl'r n;tla~>nal dd,·n-.c iiL'll'>-itic~ for "\l'l lilh }''ah. hq!lnnrnj! wrlh lht' M.anhan.an l'r<•Jl'd sn the 111-UI''. l>ulln,l! rh" tllliL' l.ahorahlr} opt·r;rllnrh ha••· hn·n

\JrtCI)' "' ,,t~' ( ··mt.rllllllJnl~ \lotlh P•"'lhlc na:gaiiVC rrnpal'l\ to woundwatcr lllduda: radt .. nuduln .

.-ha:nm::tl .... h,·nh. and llll'lal' Today. tha: l.ahuralor~ i' re,pon,ihk 1<11 cn,uring that nont· nlth pa't L·ontanunant rcka..c' po,..,· a ahrL·at tn human hl'<llth rH•" ••r rnthe future. and to carry out rcrnnlial ill'tn·rt•c' lu dean up 1:nnranunated '''c'. (Jill: of the key pnlcnti;tl ri'b •~ groundwater L:ontamin<Jllon. JliiS~Ihly allcL·ting dnn!..mg watL:t '-lualrt} 111 municapalor prt\ah~ v.clb.

l'o confront th" potenllal prohkm. the l.atmratory and the U. S. Dcp<trtmenl of Eni·rg) (I)( lEI ha\c.thr•'ll!!h the .Jl'\d•lplllcnt nf the H}drogcnlnJ.!Il' Wurlo.plan tLANL. llJlJlO and other Em·•ronrncntal Rt·~toratJOn (!;R) Protect adJVtllcs. laid out the prioriues tor chanu:ter11.ation and r~·rncdtation activitic ...

l'hc J.ahor;•lt'IY has ··~tahli,hcd priorllin for dean-up nl area~ of lo.nown contamination to 111111gatc future nugr:allon ,,f umtaminant~. and ha., .. uppon•·d dlons ht charactcn/.c and model sites of known or o,u~p.:ctcd n.·k;a~~- In atlchtum. thl.' I.<Jhoratory is al!>o engaged in a program of well drilling to characterize the uns;Huratnl /•lfle and regHmal a4u1fcr am! to mcasurt• .-nntamin<Jnt conc.:cntrations in the suh .. urfan•. Along with thi' charactcriz:.lllon and dean-up cffon. the Lahoratory is developing conceptual and nurncncal

rnodds of t~rnundwatcr llow and transport. By dt•monstmtmg an adequate understanding and ph:dictf\·e capahility for l'illltaminant tran<.pon at the site. n is possihlt• thattlw Lahoratory will he ahle to t·ar~fully monitor the rate nf migratiun of \ome contaminant plume' without cleaning them up. unl.:s~ p<'l('kt:l~ of

>' ,·ontanun;mt~ ar:· found thatt·xcecd sati.~ l~·wls for groundwatt:r. Thi~ roncept. known as momtorcd natural ath:nuation, s~ far prderahlc for contaminants that haw alrt~ady spread over large distance" in the

'uhsurfat'L'. l>ccausc n:rnediatsun tcc.:hnologics tn handk such contaminants arc known In lx· tnadcquate or very ~·:~~pcnsl\·e 111 many in,tance'>.

The mon1torl'd natural a11cnuat11m o;tratt'g) r..:4u1re' n>\~'lplimcntary mmkhng w dL·rnonstratc :1

quantitali\C undcr~landing nf the rclc\ant groundwater !low and transport procc~ses. AIL"~ Alamos. many rclca~cd wnwninants arc prc'ielll in tluids still residing 111 the unsaturated 1nne. Therefor.:. understanding .... ~ and l>ctng ahlt: hi predi..:t the flow and transport hchavlllr in the unsaturated /.one i' critical to the success nf thi~ strate!_.!Y· Charadcrit.ation of 1hc suhsurfat'L' hydrnlog) ;md tran;,pt)n in the unsaturated tnnt• to the degree n~·~·dcd to •mplcmlc'nlthis srratcgy i~ a challenging act1vi1y. given the wide range ofrt·chargc rates. the pre,en.:c of perched water. and the introdu,~tion nf a ho\1 of .-onlaminant' ,,f ,Jiffcrcnl chcrn"·al

prorx·rti~·'· A~ a first step ttlward developing a prediciJ\·e hull that .:;m tx· used tn s1mulah: cnntamrnanl migralllln. we attempt tDconlirm ;1 conn·ptual model ol un,atur;ued groundwatl't tlol.\ fnr the BantlcliL·r

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l'hc prnt·nt ''u·l~ c\,llllln,·s the rc,ull\ nl ,, Y..ttt·r tnlt'\'trun lt'st pcrforrnl'tl rn th..: urh..tluratc.l lone ill 1."' ,\l;rm••s '"'" rql<•Jinl hy l'urtymun ,., .• 1 1 lc,ll'i 1JJ. Thr••uph;, st•nn ofllll'il'Urcm~·nr, (II Hllll,tUrl' rm~tratron .11111 ;s.: .. ompull)lll)! 11Hllldrnv. Yte tlcrnon,tr;sh· thalllt<' llt~>\CIIll'lllllllllor,turl· throlll)!h the

hydroarcol<>gr, ~·ttmv lor th<' uqe~.·tiiiO t~·st. tlw 'hhrrq!<' Mernhcr ,,f th•· B;mddrcr Tuff." a -. .-tcmth;tl" pn:vaknt throu~hout rhc '-"~ Alatrlt" sllc. l'urlhnrnorl'. th .. · ch.Jr<ll'!l'rt.,IIC'> of thl' lulls arc ""ular ro other 'lle!>o. induthn!! tho: polt'nllal nudcar \\la,tc Jl'Jl""tory "'e .u Yun·a Mounlatn. Nn·adu Thcrctorc. rhc un,aturatcd ,,,n,· h~Jn•logt,· pr•ll"<''"-'" stmlred here slwui.J have a j!crwral apphcahrlit} ami "llcrl''>l th..tt g ..... , f'x•)otld rtll' paru,·uf.tr "'l' at whrch the test ""' ~anrnl out.

Conceptual Model for Unsaturated Flow and Transport on the Pajarito Plateau

L<h Al<tnh)~ Natrnn;tl Lahnratory. a4 ~-~4u;ue-rmk filrrlny hx·atcd in nnnh-..:~·mr..tl ~l'V. Mc:llr..:o. srt!l Pll till' Pa1arito Plateau. a ~cries ol rnc:o;as wparatt·d hy canyon~ that run rn an L.t,..tcr~} dire:~:! ion. Tlw phrtcau •~ houn•kd on the: Wc:~t t.) the krnc1 volcani<: fic:IJ. and on the: F.:t_,, h~ the R111 Grande. The L<thnratory "located in a '>Crni-arrd region. v.·rth low recharge of fluids over mn.,.t of th~· sitc. f-tnwc:wr. there arc known''' hc location~ where focw•cd rc~·hargc takes place. Mostnotahly. -.cvt:ral canyon~ 'udr as L•rS Alamos anJ Puehlo canyon~. are watcr~hcd~ that provide focused flow paths for surfa~.·c w;tlcr flow; pcrcnmal or cphl'llll'ral str~·am~ arc l'llllllllon in the canyNl'\ that cut throu~h the Plateau. A ,·nmnhmly tll."'-·urnng ohscnatwn ,.., thl' pre~cn,·~: of ~mall hodic!> of ~uhsurlac.: w;ucr a1 tht· ,onta .. ·t tx·twc.:n ..:anyon·hnttom alluvial dcpo-.u' and rhc underlyrng tx·llml'k. '!'his alluvial groundwal.:r i~ not ,ufti..:rcntly extensive l•l he 'OUII~thlc for minrnl! of thl' v.a1cr for domestic usc. Ncvcrthclc,s. lhrs v.atcr rs an rmpurtant ,·omponcnt of the suhsurface hydrologic systl'lll b~cau~c most recharge on the Plateau prohahly on:ur~ from thi!> .;ystcm to thl' underlying nrl'k 'trala. ~urthernu•re. Lahnra111ry ~·onlaminanb introdu~:cd into tho: canyons can lind their way rnto thi~ '>hallow groundwater. Therefore. this grountlwall'r

' tlnw may rcprl'scm a pathwa} fnr <.·nntaminatron to mrgrat~ to o;ignrficant lateral distan~:co., and rrc.ucr depths.

The (:on~:cptu<rl model for un~uuratl'<l 1on~.· flow and transport at this site rs ha~cli nn the mndd outltnelllJUalnatr\cly in the H}dro{!culngic Workplan tl.ANL. ll)'lK) and shown schcmaticall> in Fil!ure I. In ih ~irnpk·st f<>rnr.thc conceptual model for un~aturatl'd flow drvide.~ the Plateau into dry rncoo;a~ cand in o;omc ca~ .... dry (·anyons) and wetter canyon .... Contarnrnant travd tttncs arc anticipated Ill hi.' long for ... oun:c' <'llllllcd on mc:-.a,. hur rna~ he ''!?nilh:anrly short.:r fur nmtanunanls in ~:an~'""'·

Vanou~ l<'<'hlll<jiiL'' haw tx·en empl<t~l·d '" <onlinu '"" l'lcmcnl &lithe cmll·epru.&l rn•11kl an<l hl ·~~1111\ill<' mllllra1111n r;un. lto!!<'f' <~I aL I I'JlJtll "•mhmnl lll&ll\1 urc •••nlt'nl lllL'<I~.urL'ITIL'III' ''''"' .-nrn \\llh IIIL'ii\UfL'IIlL'Ill\ of lhL· Un\;l(ur;tiL'd ,·haradL'fl'\lll' ,.IJf\L'' IOC\IIIllilll' lnlillr<tllllll f<tle ill \aiiOU,J,l(alll•ll\ ;trnund the l.ahorahll). Th'' nwrhod "''lllnL'' ''L'ad: ,,,,,,., <cru..:;tlllov. under unll·!!raJt,·nr ,·,,niJHton,. tor wlm:h the un,aluralcd contiUdiVII~ e!-tlimatcd at lhc mca ... urcd watcl .:onlcnl C4JUilb the h..:almfthrallon r;!lc lnfihrat1nn r'IIL'' on rnc'a' were c\tllllal<'d '" tx· a' 1 •.• \\ ..1' IJ.IItlllllll/y. wirh mu.:h h1ghcr •alue' onl) t11und whcrL· -uri an· di.;,turh<tn\:''' .;111:h a' pond' ;~hacd rhc n.rlural ... urfaLT condition,. Nc"'m.tn I I 1JIJ61 and Btrdsclll"l al. 1 ~OIIIJJ n:port ... wular rc\uh' lrornc,lllll<IIL'' '·"'"~the dJioridL~ nm:<.o; hal;mn· rncrhod I e.~ Allison .:1 a f.. llJX'i L , h"''''"l! a , ... n,crv;tll L<e upp .. ·r hound of I 0 nun/y tor pall•rrnanu· a.,,,:,,rncnl cilkulall<lll,. B ~ ,., >nlraM. Rohm,on cl ill. 1 I'NlJ I. u'rng 01 v. <tiL'r hudgct \ludy of Gray 1 I <N71. L''illll'.tted mfihra1i11n nil<'' on lhl· .. r,kr ''' :::!0(1. IIKHI mm/~ 111 l..<l\ Alantn~ canyon in lh~ vinnily ,,r l.ahorahtry •~dmiral a•~·;h !'Jurncncal "rnulatJOIIS rr~~Cnl~d hy Rnhlll'-1111 Cl al. 'I 'NY) showed I hal the~c !ugh mlllrraltun rate' proqJcd a l:!""d matdt to walt.'l .-nnlcnt proftlc' llleit"ured 111 Lo' Alamo, ..:anyon m well LADP·.'· v. h~rras rare' on the order of I nun/~ W<'fl' nct.•,kd on lfw rn•·sa top' 10 malt·h lhc rc~;uhs fron;'' LAOP-4. ;r wdl ln .. ·ared on a llll.'''' adjact.'nt to 1. .. , Alamos .. ·any •• n.

In all rnc,;L' and al m:tny loctlton" wllhin can~ nns. I he 13andclier ruff is thl· firsl ro..:k type ,:nl.'numcrcd ht.'ncath ~urfacc sml~ or allu\lulll Tlwrdorc. n mlarnrnant:-. rei cased a1 the surface mu'l migralc through the Bandelier full. 'Tlte Banddtt.'r lUff j, c•Hnpriscd of 1hc 'J\hircge Mt.'mhcr and the Otowt Mcmhcr. lhc,c nx:ks arc muhrpJc.flow a~h·llow .. hcch lhalt)pi..:ally rcprl·~cnt the first unit..:xposcd on lhl· mesas uf the Plateau. lklll'alh rhc Bantldrcr tuff i:-. lypictily a horiton of fanglorncratl: dcpo,,r, calkd the Puyl' Formatwn. w·hidt may or may nol tx- intL·rl·alatcd w alh Ba.,alrs ~uch a:-. lhL~ Cerros del R1n Basalt. The Pu)'~ f<lflllilllnn con''"'" nf a V.tt.h: range of rnd. fragmcnh. frnm ""Hl.Y or daycy material.. h • holdcr-,1/l'll. The Ba,ah' arc ltkl'ly tot.'llhihll fraclurc fl,>v. under un,awraiL'd or ~aturalcd condilions due'" lh<'tr '""' maiTill pcrmcahility and columnar jointing paucrn. C'nnlarninallls r~arhing I he warcr tahll· of lhl' regional a4uifer d(l 'o within the Puyl· f,•nnation. when· I hey arc prc~umcd hl travel laterally ~uhj.:cl In rhc prcvatlinl! dircl.'lion and vcl(~<:lly of groundwater flow ThL· main porcntial receptors of wnramrnilted !!mUnll~o~.alcr under lhis o;ccnario arc tht· ust•rs of the domesllc water '>Upply. which is dcriwd hom a nciW<lrk ol v.alcr .;upply wdb m the arca.

(itn·nrhe charactcrr. .. ric~ of rh,· Puyl' FMmalton and tht• Ba!>ahs. thcrl' rna)' hl.' raptd lritn!>port of water and cnnt.uninant~ nrK'e rhey reach lhcs<.' unil.,. The Band\'lrcr Tuff. on the orhcr hand. 1113) provide a ~•l!ntfu:anl harnl'l Ill ronlamm;ull nugration dul' to it~ rclativdy porow. and pcrmc.ahlc chantdcr. J1,,wever. th•·rc arl' \anou' degree~ of v,.cJ.Jmg within thl' Banddter Tuff. ami many of 1hc suh-unit' l.'t'·:llam tra<·turcs thatrnusl he lllll,it.lcred a' po-..~ihly fast pathv.;~y,, ThL·rcforc. for this rock to allcnuatt thc infrltrauon of ··ontanun.tlc<l ground<l<;.llcr. it rnu~l hl· dt.'mnn-.trated tlut \\aln JX'H.'t>laft'' lhrough lhc pnr, .. u, nx·k marrix. rathcr I han ··h;mndmg rhrougl1 fral.'IUrl''· The purpP"<' of lhl· \~all'r illll'L'lion lc'l anal~ .. i .. pTl'St'llll'd in rtu ..

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rarer;, to Jll;JJ.l· Jlllerprt·t;all•lll' from n.pnlllll'lll.al ··h~nallllll~ ami model in!! that art: rd.·vanl '"I he l·riucalt!\~Ul' ,,, lra~·turl.' \cr'u~ matr" flow 111 the Uanddier Tuff

Conceptual and Numerical Models for Flow in Unsaturated Fractured Tuffs There ;arc scv~ntl d1fferent approachc' li1r ~1mulatmg tm"uurated flow and tran,port m lral'lurcd

tuff ~ystem~. \'1swanilthan ct al I~I)(Jf)j surnmantl' the ;tv;tllahlc modch that have h..-en u~J to cxaminl.' the role of fra.:turc~ an un~turall'lltuff~. wnh ernpha~i' on undcr~tandmg the hydrologic hchavior nf tuff~. Thl' work JX•rforml·d to date ha., 1(,.-u"ed at prc\cnt on Ylll:l'a Mountain. Ncvadil. the pott:nll;sl ... ite of the Natton·~ h1gh-lcvcl radmact1ve wa,tc rcpm.itory. With \arym!! dl.'gn~l'~ of assumption. each modeling approach ~·l'k~ tocapllm: thl' rok of fractures em hydTI)Iogy and trotn~port. Three common In< ll.lchng approachc-. ar<·:

• Discrete Fra~·tun: Model: The discrl·te fra,·IUn' repr•·,l~ntatiun crnhcds fraciUrc!i wuh di!>tJJKI hydrologic propcrtic' wuhm a model Jomain th<tt indudcs the rod; matrix. W:.tcr can citl.cr channel through the fractun: or imhthc intn the matrix, depending on the hydrologic properties of cud• mcthum. Nnao and BuschL·ck 11991 J, Soli and Birdsell 1 11NXJ. and Vt~wanathan ct al. (2000) used thi!'> apprnal~h to study fral.'tun:-matrill interaction~ under unsaturutcd condnums.

• Dual Pcrmcahility Model: In the dual pcrmcahility method. hoth the fracture and matrix domains arc di!>Crcllzcd usm~ the same numerical grid. g1ving riSt." to two mdividualnmtinua with a one-to-one rnappinf ••f ~rid points hctwccn each domain. At cm:h gnJ point. the matrix is abo coupled to ttll' fracture" through a fir~t-on.tcr interaction term. [kpcndang nn thl' naturl· of thi~ interact inn term. cithl'f a fral·ture-dorninatcd. matrix-dominated. or a comhined fracturl·-rnatrix llnw regime results. Detail'\ of the model formulatinn can he fnund in Bodvarsson et al. tl Y97) nr Tseng and Zy\'oloskt (2000).

• Equi,alcnt Continuum Modc.:l: The I.'•Jlli\alcnt con11nuum model simply allempts to .:apture ~·haractcristil·~ of llnth the fracture'\ and matn' w1th a ''"!?lc ~et of properties. The primar:r as~umption m thl· rnndd •~ that the t:aptllary prc~:-.ure an the lnt,·turl·d mcd111rn C•JUab that in the matrix I l'et.:r~ and Klavcucr. 19KRJ. Thts approach is ~•mpkr '"rnputationally. hut it ~·annot ca.,ily rcproc.lu.:e fra.:turl·­dormniJICII flow and tran~port l.tmits ,,,- th,· ;tpplll'ahtlity of the ITM for fluid flow were t'll.plorcd hy Pruc'' l't al li'NOJ. ;md \',,wanathan l'l al. liiJ9Xl ,·~t1·mkd thl' analysis to include soiUll' transport.

Each method ha .. II~ trade-ofh hctwccn the rcal1~m \\ 1th wl11d1 th•· actual phy~ical sy~t..:m i<. rl·prt·~cntcd. the availahh: data l·haractcr11.1ng thl· s~·~tt·rn and pro.:c"e'. and thl' etlicicncy <llld applicahi!Jty of thl· numcn,·~l mdhcl\l fundam<·nt.all~. the '''Ul' ol ga·atl''' lllJportarK't' I\ the dcgrl·c hl which fr;t.:ture~ channd n()~ thrnu~h the nl\·h under un.,;llur;atl·d cnnd•t••'"'· Tlu~ "'uc h••~ been explored hoth thl•oil·til:ally and l'l(ll'rtm..·nt;all). ~tloto and Bu"'·hl·c~ I JIJ(IJ J l'\alllllll.'d oan nlc;~lunl 'Y'Il'ffi of parallt-1. eyually ~paced

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lr..,·turt·~ v.1th v.;~t~·r l'Ott·rtn~ ill tile tor. antii!IIJ!"''"Ii! ,,,,.,..nl.\;ud un.kr vro•\11). Thq •hi>"-t:d 1h111 rod.~ V.llh laJft· por"'ll"'' otfl.ll ~·rnle.·alllflllC' h;J\C it '11"11)! 1.lll\tll~! lor~~· lor water t114JUI~Id) 11:1h1t>.: 11!1" Ilk: >f' llld. matrt\ I :rHkr 1111.''4' ''''"'"'"lh,ttk· V.illt:l ,,.,nl "ljUII~I~ .tlll'fiUolll'd. iWd 10 the hniiL lh·· duV.II\\oUif· tllf~lllllfiJ,' "'l'll!llj! JI.,OI ,.,..._.flllotlf~ O\'lt;l\1'\ ,,, lh"U)!h lh1· I loll lUI<'' <lit: nut pre'tl'".l. l·.-fll:IIIIICIII.t!l~ Hll.,'>Cotf ,., at 1 ~11110) ,.,,. 'tud~rnw ttw lr.tn'J'I'rt ••I V..tlt'r ,;aol ''·'' ,.,, '"'"''' un,,trur;u,·,J ,·on•lll"'"' 111 ;JIII.'\jll"flfiii."IIIAI ,., •• ·!lrty at n.,,, •.. tllullc. 1'-;n.tdit. ,,, ......... ,, n.·ar rh.· r•olen1t.tl ''""""'"') ;JI Yu····a Mnunr;un RuhiOMifl anti flu.,.,.d 1 ~011111 ,fh•w•·d lh•· rc,uh~ ol an lnfl'l'llltn h:'l 111 "''"' h the: prl''t'lll:C ol a lrm:tun: 111 lh•· nonwd,Jc,f. rcrmr:ahk CaiKo lfrll• tuff app.·ar.·<llt• haw "" dlo:•·t .. n rtt1: IIIIJ!riltlon ol water and uan~r itway hom 1t11:

fk~·au ... · of thc:"l' w'ult,. we \:hn"l', rn an lrtiii.JI allempr ro '"nul<tll' lhL· rc,ull~ of lhc ~.~oatcr in)l:dl•lflll'"''ll''dlh..·.d tn lhr prc,,•nr ,rudy. In model thl· flow l'lcha\1or u ... mg a .:nntmuum appwa,·h that .:on~!dcr~ llUid Ill'" o!at~<tn 1hrnu11h the matn~. "'llh "" tr:ll'tme ..:ontuhullon. Thl·rcforc. v.c t.a\c ''"'l'liliuJ the rqut\aic:ll! ,·ontinuummodd h) •gnorrng fracrurc ... alrogelhcr. a~'lgning matri!l ilnv. r•oJ)I.:rtie' llllhl' n'H.:k'\ rn a~T~trdance wl!h rhc h)'drolugu.: p<tr;unctL'r~ m,·aMJrnl •>II lalloratory ~ample~. In so dwng. we arc te,tin~ thc hypothc'i' thai lnr the Bandclu:r Tull. rlw matru dorninall~~ the flow hchavior unJl.'r un,aturatcd cond1tion~. An a•kquall: match Ill the data wtll \ahdatl.' the nnw rncL:hanism. whereas a poo.lr lit. cspc:l·ially nne lh:U undt''llrt•dil.'l!>t downward travel \'clo~ollll''· v.tll he 1. au .. c hi •on~idcr more compkx model'

Water Injection Tests in the Unsaturated Bandelier Tuff In the 11.)60''· Lo' Alamm Nahonal Lohorahlf} and the t;.s. G~.·nlogical Survey rnnduned a -.eri.:'

of h.'~h tn c~plor.: the Jlt'~"hk u..c ,,r inJc~tlnn well' fm water di..,posal. The original mtenrof 1h6c ..,tudie~ wa~ hl dcr.:rmrn~o: •f .. hallo~~> tnJCt'llltn welb \lnllcd mto the un,aturatcd /.one on the Pajarito Platt~au could Ill- u..cd hl '"ft-ly d•~Jll'~· ol h4u1l1 effluent t'rorn l.ahnrahlf) olpt·ratinn~. Tht• mcth111.! wa' nCh'r u.,cd at Los Alamos. and ~·urrcnt rc~uhtllon,. along with the Lahoratory ·' dc"Jrr to he rc:sponsihlc -;tcwartl!'> olthc cnvironnwnt. prlx·ludc !hi\ t'<lfll:ept from l'Vcr hcing Hnpknlt~ntl•d. Ncvcnhcks~. dahl collc('led f11llll IIIJCCII11n It'"" \:arrn·cj out m 1Yfl5. ~.~ohrch used un.:ontanunatcd water . ..:an he used hi undcr!'>tanJ the hydrolt:l!!lt' rr•ot..Cl\"oC"o ~o:nntrollmg the movcmcnr of lliiiiSturc '"thl' Ull!'>aluratcJ Randclil'r run

lnlt>rm;tllon ~·c•llcrtcol frnmtwn tc:~l areas • .., a\aJiahlc: fnr mtcrpret<ttion. A n:J)I.•n h' Purt}mun 4'1

al. 1 I ':1'1<1./ 1 ..,urnrnant.:.., the go<~J, of these tC\t., tn he:

• T•' UJ\'''""!!alc rhc: rates of '"JCl'ltnn <tnd I hi.' opcraung nmdlltnn-. under whit·h the 111ft'.. would an·crl wJtcr: and

• T" monitor rh~· movcmcnr of moisrurc from the intn·uon lo\CIIto the surroundin!! tuff Dctailul tlc"·npllnns of the rc,ung tnethcll.lolovy. layout. and measur~.·nwnttedmiqu•·' ar.· pr•·,erllt'U 111 Purt~·rnun cr al I)IJX\Jl. "' onl~ a hricf ... ummary ,.., giv.·n here: Till' <'•>mplc' of in.ll'CI1on i!lld oh ... l·r\atl1•n \\t'"' art• lo'H.';.!It'llllll il narrolo\ lllt'!>OI adtaCL'IIIIII rcdlm~··' An·;· "O ITI\-~II).tlll' \Ill' ot lh<' l.ahnr.lhlf\ ·,

'"

r;~tlto;ll:lt\1' "·"'~· tn·.ttrrk:lllla~tltl) Thco,c \lodk 'h""'' "'lllotJl \-ll.w rn hgure 1. au.· ;slllolllpktcd mthe upp:r l\hlll")ll' \kmhcr. a"''"~'' ••I nonwddccfl., wddnl a'h rlow tuff,. The inJeCtion fl',l~. v.crc: 'ondu,·tcd tn a pha"t'd appro;u.:h. \!ollh lour prdumnary )!fit\11~ ·!In" tc'to. ••I ~fl. 1-lO hnur•luratron uw•J rnarnh t•• ''''''i!" 'Uil"<.'lfiJI'Ill tn1•·~·rwn and momto1rrn~ '''J'II.'IIIliL'nt' Then. tlnn· longer durallnn IC\I~ \lot'rl' p.:rlur med tn wh1d1 Hlot,wn· llh•nttflllll~ "'"earned oulln tr;Kk :he tno\'l'tlwnt pf lluill~ throurh tho: un,aturatcd tuff',.

I ht· ''-''' lor whr,·h numcm:al rno~dc:ltn~ ,, Jll'rlnrrm·d m tho: Jlll'''-'"' study l•·~lled ·'To:'t I :st Sllc z·· m Punymun ct ill . 141'19 J. ··"""\''of an lnJl'dton P'-'""'1 ol XIJ d;sy• hgurc .l show' the tnJe'-·tron 'Y'>tcm 11\l'd lor the tnt \\lat.·r hnrn lllUOKI('lal watt:r '"tlfl't'' "'''' pumrcd rnto a :'iOO )!a lion '"'rage t<tnk. whodl dt'o!:har!!t'tllllhl a 'HJ<illl'l Jrum (ontrolled 'l.':'th a float •-ahc In m:~intam a nmstant pre,!.urc at tht· ground •urfar.:t'. Ttw '-·•n,:h dii!llll.'lt'r lnJCO:Iulll "''" wa' ,omrktnlro a depth of fl:'i feet. with !!ravel Jo .. ~ated in the lnfl'<'lllln mnc from :li:'i lo 1'15 ti:l.'t. and l.'cmcnl a how and hclo\lo. The l.:?:'i -inch injc,rton plfll' wa., lilted "'llh a pcrforatl.'t!L·ndrrl~<.·c 111 dt-.tnhutc the flow A -.~r·•nd 1'1'1~ v.·as al~;o installed h.J monllor the downhole pre:'I'>UTC

h~urc 4 'h"w' the me••-ured flow .. :ondlltnn' .lunnJ.! tht· ll~''· De~pitc lhl' con~tant prc,~urL' .-nntrolkJ at the 'urfan·. thl· inJL'Citon·/one prt•,,urc lhgurt· 4a) ohihttcd variations withm the tn-.t ~0 days lll:foH· ''Jhllll.mg for till' remainder of tht· tnjcctllm rcn•l<l. In gc~~.:ral. the injc<.·uon rat"' ihgurc 4hl was invcr'll:l} proportional to the pre!> sure. Pun~ mun ct al. t I 9W:It nit' ptl~'ihll' cause-. to he 'ariauon .. m atmosph .. ·n,· , .. ,mpcrature and prc.,-;urc. and di.,solved ga' tn the IOfCl'll'd flwd. Any of theSL·l'fkl·t~ could ,·au~e the lox:al conditrons in tht• rock immediately adja~:cntto rh .. · m.rt·.-rion rcgum to he affcdcd. We \it•w these cffi:..:ts to hi.' of rclatrvcl~ mmor o:onscqucnce for tho: purpo'-1.' of thl' study. which is to monitor and mtl<lclth;.• mtgration of flurd through the un .. aturated 1nnc. For -.rmul:~tlllf the proces~e' contn1llin~ this migration. the time-\arytn)! r<JII.' of water injco:tion is requtr .. ·d. Th .. ,rdorl'. th~ ttmc dependent injection rate of Figure 4h '' u:o.cd a~ dlft'l'l input 111 the m1J<ld. The l·umulall\\' ma~s nf water injected wrsu~ time j, shown Fivurc 4..:. A tntal ol 1.17 ~ 1011 ky of water wa~ mjcctcd during the !!9-day inJecti•m phase of the e\pcrimcnt.

M111~turo: momtoring was carried out w .. ing neutron logs of the \Urwunding wdb \!ol'l' Ftgurc 21. Thc~cdata Wt'rc u-.cd hy Purtymun el ~1. t IW!IJ) m tw11 way'. Fir-.1. data frnm wells N-1 ;md SE-~.located do"c In th.: •njection wdl. were u~d directly tn .. lct..:rnunc till' raft':-.. of movenu:nt vertically upward and downward lrnm lht• mjecllon region. Thc~e dat;t arc pre,cnrcd wtth the lll<ltld comparis1ln in the next !.l'l'lion. Al-;o. data from all \\ells were used to measure th..: t'\tl'nt of lateral migration and to ~·nnstru .. ·t rcprcscnlall\'t' .:fll'~ o;el'lions of llloli'>tUrt~ contt•nt at vanou' time~. Thesl' eros~ '>el·tion-. wen~ ,·onstruo:tcd hy rr•>ic~:tmg thl· rt'\Uit-. from all hotcholcs onto ;I ,jnglt• lfO'i'i \l'dlllll. Figun.· :'i. reproduced from Purtymun cl al. 119XlJ J. -.h,,w, thc~e cross 'ol:<.:lions. The frT\t four . .:•m,trucred frnrn tlata at 7. 21J. 55. and !W d;1ys after the starl••f lllll'l'IIOn. ar..: during the pUIIIJ\illg phasc. "-·hllc the la\t <llle is fmm data l'llllc..:ted at day .~27. 'omc etjlhl month' after injection v.as -.rnppl.'tl A' a vhcd, nl tho: \illllhty of these t\loll·dtlllt'll'Jtlnotl rcpresent<rllllnlo Ill lht• d01tos. Purt)mun ct al. lllJHlJ1 al'n ,onlirrncd thatthl· lllll'grated amount or'tllfl'•'ted

7

wal'-'r unpiled h) lhl' con,tflll'tl'd no" 'Ci.'fl•m ••~rc'-'d do~-~~ w11h thl' known amount ol w;tln 1111n:ted. Th~·rcforl·. all•nt•••·tcd wat.·r '' approl\10\atcl~ a.:, .. unlnl for 1n the lf'"' 'cdion~ ~hnwn.

InterpretatiOn' ol rnca,ur.~d ,hapl· anti "''' ,.,.,,~ oiiii<J\l'lll<'nt nl the water plum•· will he pr~·,t·ntcd Ill the nc\t "el'llllll

Numerical Model

V.'e u'e the hnitl' Ekmcnt H~·at and Ma~' ll·T:HM 1 -~-..kIn pnfnrrn lh~· numt•rical simulauon' presented m this paj'll!r. Thi, \.·ode ha' hccn used c'ttCnMvcly tn modd un,;llurat~·d and saturated flow and contmninant transport in polfi'U' and fractured media (M:e for cxampk V1swana1han cl al.. 191JH. Rohin!>un an\1 Bu,so..t. 2000. Viswanathan ct al.. 2()()()). Detailed denvatmns of the governing equations of two-pha!>e llnw a,

. impkmcntcd in FEHM have hccn des~.:rihcd prcv•ousl} lZymlosJ...i. 19R1. T~cng and Zyvolo~lo. 2000). The ~·,,Jc usc' a l·nntrol volurnc finite volume approach to dJ'-4:rctiZl' thl' finitl' clement domain. Thi' technique pnwidc-. the llc,uhiluy needed 10 l·apturc thl' rornpkx geometric~ ,,ftcn enrountcn:d wht~n modeling ~uhsurfa..:c llnw <Hid transport. In the present study. the modd u~~ a -.implilied ).Uhsct of the balance equations hy ;l).~unun~ •~othcrrnal. two-phase flow of .ur and water. Thi~ simplification reduces the cmnputatmnal burden without ~acriticing needed phy .. ics. S.:vcral solute transport options arc also availahh: hut are not used in the prcscm study. For dt:taib. sel' Zyvnlnski l't al. ( 1997). Viswanathan ct al. ( 191JRJ. and Rohinsnn et al. t2CKlll).

For umaturatcd medi;l, the relationship hctwel'n Jll'rrneahility and fluid !>aturation i~ rcquncd. For this mndcl. Wl~ usc the moisture charach:nstil· ..:urvc modd of van Genuchtcn ( 19801 hecausc the availahlc site data mca~urcd on core '\amplcs have hccn rt·duced usin)!th,, model. Tahh.' I gives the characteristic r:urw parameter'. tht· \:lluratcd permeability. and porosity for each hydrogeologic unit in tlw model. The data are ohtame1l from Roger~ and Gallaher 1 JlN5 l. who ..:nrnpilcd the data collected lor the Bandelier Tuff from -.amples <.'nllecred from nurn .. ·rou' hnrcholc' on the P;~tarill• l'l<~h:au. The values Cllt~d in Tahlc l ;~re mean \'alul·~ nf 1he parameter' puhJi,hed in thai .,tudy

,\ thrct:·dllnensinnal numl'rical grid "'a' construt'k·d to paforrn the numerical modeling. hgurt• 6 .,hnw' a top. ''de. :mJ pt.·r,pct·uvc view of thi' grid. lnnca.,cd honJiHJial rc,olution rs used hl capiUfl' the flow ')'1..:111 n<.·ar rh.: Jntl'l'tion rcg1nn 111 detail Th.: vcrl•l·al rc,olwion i~ variahlc for 1he same rca,nn. and to allow the 1nterfac.:e' ho:twl.'cn the variou~ hydrogcnlo)!ll: lay.:r., hhown in the side viev. 1 to he captured . . Vcn•..:allr":atJun' nlthl· l<~ycr .. arc haM:d on the gcoiP)!IC.: mndclol thl: LANL .. itt• ..:onstruC.:tl~d hy Carey ct al. c I~ 1 At th1s locaunn on rhc Platl·au. thl· mtnfacc., <trc rlo.,c to h11riwntal. sn they arc r..:prc,cnted this wa) for "rnrhcil ~. ·lne nurnen~·al l!Tid rontam' 'i '.191 node"-.

The tl< tundar;r c.:nndllion, arl' no-flow "" the f.,ur ',~rtic.:al face!> of the modd. and con-.tant tlutd saturallnn on the h •p an.t hl1llolll. All houndanl"" arl' tar t~nough rcmowd from thl' injccuon intt:n al that they have"" t:flt•d unlhl· "mulatt•d rnn"tun· pallcrr" oflhe IOJCl'tcd lluid. To c'lal'l· '· :.1 had.f!rouml llo\1. field \Uit..shlc lm 'tJrllll~ lhl• Jnll'(llon \llllulatl< >n a fluid \ olurnctnl· \\-ater,. ·• ,,, :1! • ·I 0.05 wa .. 'el at the

i

".

·,:J·

lllJl, anli thc ,v,ll'rn ""'run tc• ;1 'tL·ady·,lat~ (ondttron Hurd lnJ~l'lron "snnulatl:d \\llh ,, ... uwt·~· fl,, .... r<llc: h'rsu' tun~ \hllwn 111 hvurL' 4h Tht• wdlhorc: ;111.! '"J~CIJon /llllL' •~ notL·<iplurct.lm dctarl "' rhc: nt.~<.lcl. ln~tl·ad. HIJ<.:."IL'd ...,atc:r '' rnput ;tl a -.mglc nmk ''' lhL· appropnaiL' (,,,:alton in lhc model l"h<~ 1 Ulflll'lhtnn ol tht•t·onlrnl \lolumt• '"''oc1at~d with 1h1' nock" "mrlar loth<· '"L' of thL· rnjc:clion imcnal. ,., the rnpulol v.all'T mtn ttw rod. fll<l'' ''captured in th~ llltllkl. c:vcn 1f !Ill' dctarlccl paiiL'rn' ncar lhl· wdlhorc an· not. lntc:rprctaltotn' .,., rll f•x·u, on thl' lltllH'mcnt nf tht· llltll,lllfl' plum~ at 'l~·nificant c.list.ancc:' I rom thc: lnJ<'l'l 1110 p<llnl. and no all<~rnpt Will ht· made 111 rwuch dal;t contrnllccl hy prol'l''"c' •x·curring ncar the IOJc:llllln poini. SUCh a!\ lhc illJCCIIOil·IOOC ('TCS\Ufl'.

h;!Ufl' 7 'how, lwcHhmcn,innal c:ro" ...c•.:tion' nf \olumc:lrit water c:omcnlthrouJ.!h thc lhrct'· dtm&:n'iional model <II Innes n•rrc,ponding lo rhl' morsrur~ plume' c:onstfU('tcd from the dal.a r hgun: :'i J. Many t~krncnr!'> nf thL· mca,urcd mmstun: migr.ttlon arc ,·aplUrcd wcll hy the rnodcl. The )!en~r;tluun~mcnt of rnoi,ture I' rn all dircl'!Jon,, hut prcdormnanlly dll\1-n.,.,ard. L..(mc~ of h1gh waler (.'ontcm huald n~·ar the inje,·tion point. gravnatumal forn·\ pulllhc plume dov. nward. and ~..ap,illary forces transmit fluid lalerally and upwar.l . .JS rhc: plume gnm' durmg the IO.Jt'l'lion (hgur~ ... 7a-c: 1. There: is a noticc<ahk ciTed. hoth in the data and the model. of the tran~itum in hydrolt•gll' propau.:s mthl· Jcl(;llion of the Qht.'H()ht2 mtcrface. Moisture migra110n is controlled hy somewhat different hydrologic propcrtics in the two unih. causing thc I ormation of 1wo overlapping 1.one~ of higher w;aler ~.·onll~nr. ctnc ncar th~ injection point and •me withm the Qht2 Formatwn I Figures 7c and d). After injection end~. rcdistnhuticln of moisture in the rock rn ... ,, nmllnucs during the post·injectinn monitoring period. The plume: .-onlinuc!> to migrate downward as v.cll ao; laterally. resulting in lowl'r water l'ontem-. 'PTL.~ad out over a larger volume: (Figurl' h·l.

Quantitatiw comparl'mns of model and data an• alsn po\~Jhle h} c xaminin:: the Jat:• on the exll'nt nf injection water migration. <IS mcasurt>d hy the ltxaliDn ol they,;; v.atcr nmtcnt front. Tahle 2 prcs~nls the model and data <·ompan!ion in 1hc form of avcragl' rare' ,If movcmcnt during diflcrcnl intervals of thc lc!.l. The upper portion of thl' tahlc rcprewnt:- dnwn\\artl nugration ratcs. Both modcl and da1a show ••n initial high rate nf movement. follnwcd hy ;t tapering otT of the rate a~ lht: rnoislurc plume spread'\. The l'Cntcr portron of Tahlc 2 ft.'l'l>rds latl'ralmovcrncnl oft he moisture from from I he injcelilln r•lint. whrch cxhihilr. a -.unilar trend. hut !.tarting at ~l<lwer ratt.'s. Srnce latl·ralrnij!rarinn is driven only hy l'apillar} force,, the ralc' are lower I han for downward nugration. for wh1ch gnivity also cnntrihutc.~. Finally. !he hottnm wd1on nf Tahk 2 show:<. the upward d1~1ancc that the plunll· migrated at two rncasurl'rncnt timl·~. 1hc ... cc:ond ht:mg after the cight·month post·injn'lion pcrt•l(l. Tlw-.c d1~tances arc also controlled hy caprllary force'. 111 this <.':ISl' working again•il gravity The <~grcemcnt of model and data rtlu~trall' that the conn•plu<rlm•ldcl•~ l'apahlc ohlc~crihing captu!;ag thl· kc)' hydrologic prcll.'cssc!. in cfkL'I inlhc mrcl.'lion tl'\t, and that no further t:allhration is ncl·deJ to proVIde ~• c.tuantitatiw agreement.

il~#k;.\i;rl''4r, a·ti- •iN 'v w

! J '~'

Discussion and Conclusions

An 1111~-·tltlO /011\' h~,, Ill till' T,frlrq•,· \1l'mhn ... lht• B;m.ll'lt..:r run rt•porlcd h~ l'urt\ 1111111 ct .JI. 1 II,IKYI h.t~ hec-nlntt·rprc:t.:d ;m.t mol.!dl·d u'llll! .t, •IOIIIHJUIIl mudd that l'on,ttlcr•, onl~ llhttrl~ rlnw l'ht· aJJreclllt'llt of llll' numt·rrc-almotkl and the daw "·'~ qt.otlt' .tl'l'cptahk. h11th 4ualitai1WI~ and ljttanttl;ltl\d_. Tlw llll_!!r.111on 11! !lllll,turt· tnJt'· ~t·d 111 an "IX'" lrth'r\;tl ol rh.- '~dln•>fL' .. ·.xhihllcd flo" that ~•t·' ~:ontrolkd h~ hoth !!fa\ II\ ;md ,·aplllan lt>rn·, Ho'" \\iJ' prckfl'llltall~ do 1\~ll~.ml. il' would rc C~J~l'tc:d Ullt.kl O.:llllt.llllllll' "' rd;tll•l'ly h1~h llow ratt'. l.atcral.md up••·ant 1111!/rilltnn aJ,., occurred due tn tlu· •·ap1tlar~ drt\111!! lnrre' 111 1111, un,aturatcd md\. The dlt·,·h nl illl abrupt trart\llron 111 hydrolng1c pr•>Jil'ntt•, at tht• rntcrfil.:t· hcl"'•'t'll two 'uh unit' wt'rl' at .... oll,cn,·d 111 h .. th lh<: data amltht.• numcn.:<~l lllt\(ft:: In addllmn tn th1' tJUalll.lll\l' a~?r~t·nwnl. tht• modl'l pro\ 1d~d an ad,·uu.ll~ matt:h to data on th•! rare-. 11! itll)!latlllll 11f thl.' '"at,·r plum~ 111 tht· n:rttntl (Upwanl and Jownw.udt.llld 1.11nal drr~cllon~. This agreement \\as .tthrcvcd u''"l:! hyd1nln!111: prnpc:rttl.'\ dcri\cd from laboratory nwasurclllt'llh performed on sarnplrs collcl'lt'd lrnrn tlnrehoJc, Pll th•: f>at<trrtP Plateau. thoul:'h 11111 fn•mlhe -.rtc nltht· irqcction tcstrtsdf. Thr' rc,ult lll.lY imply that rf tht· ~nn,·cptualmntkl ",·otTt'C:I. then rh~ nat:t value, ol the h)'tlrologit· pmpcrtic~ aa· not .:nll('al. a!> lon~ a!> tht· p.uanwrcr' all' JrrtH~d from thl' \alii~ h~drolo~~Jl' un11..

Co~nrrrrniltu>n that a l'oth.:cptual and numcri,·al mnlkl a).!rcl'' w rth r1cld scale data. though cnt·ourag1ng. J,~, not guarantee that other cclflu·ptualllatton' arc nnl abo \ahd. for l''iamplc. a dual pcrmcahrllly llhllld 11! fra.:tUrl·~ and lllatn~ rcdu,·c~ to lllillll\-dominall'd Jlm~ hchan •r under n:rt;till lim1ting t'undttions. It canal'" hl' argued that :1 dr\('rl'tc fra.:rurc formulation. such as that of Nrhto <lllc.f Bu~hcck 1 I'N lt. 1' ..:onw;tl'lll "1th the rt•sults 111 the ~,-n,c th.Jt 11 prcd1ch rapid imh1h1t1on ol watl'l' mto the matrix for thc-.t• ~·. pc~ of rod;.~. HnwcH'r. the l'l'ltrcal 1"u'· I' w h~·ther thl· rei~\ ant pwcc\'>n arc ..:apLUTl'd. nell whKh rnathc:;; .. rllt:al formulation i~ ch•Jsen. l'hc l'llllllnuum model" dl'llhlllstratt:ll to reprodm.c the rnjl.'ction data. ;1111! thcrrfore w·ould he favored due: to th '1111pkr f1 •rmulation and cast· with which II '' Hnplcrnl·ntnlln largc·\l'itlt· llow and transport '"nulatum'.

The rcprc~entativcnc~s of the cxpcrunental rc,ult' al'o rt•qurrc~ d1scussion. giwn that th~· data arc tor a pmnt ,,,ur..:c tnjcction from a wdlhort·. ratht:r than natural mliltral1on. In dctcrnuntllf whctlra prclercnt1al flow through fracture~ •~ occurrrng. the dm~nwarllllu\ of watc:r ts a kl'Y lal·tor. alnnf with the hvdrolog1.: prupcrtll''\ of the: n>t:k. Tot~strmatc the C4Uivalt•nt rnfiltr~llloll rail' during lht• tc:~l. we: d1V1dc the tlu1d rntcctil•n rate by the ..:rm., ...cctional an·<~,,, tlw w;ttt.·r plum~ .~t a partc..:ular time . .l\pply111!! thtS methnd at day'\~ nf 111Jt't'lllln. we <1htain an c~timatc.J tlu\ ol about ~.7 \ 10' mm/y Thi~ rate 1~ much h1~hcr than the avl•ragc 111ftltrat1on rate' e'lllnatcd for the Patarrto Plateau. l'\Cil 111 ..:an~ om •. Valul·~ thl' laTfl' prohahl~ r

•~t.·cur on I~ locally 111 area' of pnndin,g or undnnt:ath h>l'ilflnn' wllh .. trt•amtlo\\. Tht: 1rnplrcat11111 nl ''"' cakulat1nn 1., that tf matnx-domimtt~·t..lllo\\ i-. ''"":rwd attlw hrph dll't'tl\l' 1nliltrat1"n I.Jlt'' of tlu-. tlltt'dion tl''t. tht•n 11 1~ t.'H'n more lrkd) to Ot.' the ~·;t).L' undn n.1tural .-nnd!tlons on thl· l'latt'au

Wuh ft'"J'I.'.:I 111 tht• hvdrolo!!il' ~.·oml111on' cn,·nunt,·f'l~d 111 lo, alton' "'hrrc <lr"-Phcd .:nnt.tllllll;tnt:. .uc alll"\1<.'. tht'LI'Il'>l'ljUl'lll'C ,,fntalrt\-tlnmutah'd llnw 1., l••·knl'a"· 11:1\.-l \t.'lllt'lftt'' hn·nnd "h.Jt ~Anuld

10

• I ~ (

!f~..,.,~~

;~~

1": lhc .:a"· 11 prd,·rt·rllull•·h,mndJOf lhrnuJ!h ft,,,:rur•·' "''"' '" "'"" l·ot 1'\:tlllpll~. lot .. n rnt.llr;~• "" r.tll' of I nun/~.I~PI•·"I ul .. llll'''''"',.""""· .mcl.t ~ ... ,,,., <111114'111 ••I Ill. ''''"nwillll H'lonll<'' y,J(f t>.: onlht' .,r.kr <tt'U.Ol In/\ I :n.t.·r lilt'"'-', ~tlhlrllnll\, d non \rHhlllV rnnl,tlllfll,lfll frr•nf wouhltak\: 10.11011 H:,t'' '" fll'ru•lak lhruu!th 1110 111 ••I un,<~IUfilh.'d U.m,klu.:r lulr. A '"'lllar ,·akul.lhtHl lm a wcl·(ilh)'Hn .... ·cno~no I 'iOO mrn/~. 14·11tcr .:nnll'OI nlll 1~1 )'h:l•l" a llan•pt•~l \l'lonl~ ••I '!. ru/~r ''' ;rllavd lllllt' nl 50 yr to trawr.,c IIIII llk'h.'t~ , "' r3an.Jcll\'t I ull (',,,,~,r·m·lmv l',IJIHilll'' If lht• hv.SittiP!'\ l<'l'fl: c<llllltJIJ.:d hy lral'lutl'' \t.o11Jilll'll: '" reJu,·c IlK· warcr l'•IOI~nllt lo 10 'or low~·r to an nunl l••r lh<' ... mall ftadr••n oflh1· l••l;af n~>J. \'olumc thott '" lalil'n up h) thl' lra~·tuh: '''"'''pan· Tra\'d 11111n lot 11;,,,.,..._. !lw '~'II<' 100 llll'h:r-; .,,. Uandcl1~r Tutr wouiJ hi: IUO ycolr\ ,,., lhl' fllC'>:l'i and 11.2 yr ror IIW "'''' '""}""' In .. d.IJIII•II. II water ~o:nnlainm!! nml4lllllllanl!> pcrcolalc' rhroul!h rhc r•l(k muir". llr~ hlo.cl~ In ht· m JrliiiTiill<' ,·nnl<ll"l "'ilh Jhc rod 'urfaH''· Thnclore. fnr ~~nnl<~nHnant' lhar Mtrh II• 1111.: rod .. lliJitl\·llonun<th:•l tlov. IOdl'aw.,lhc lrkclihood of tl~lardallon. Thi' flltli:C'\' l'aO af~l on:ut IIUfiOf fral'IUfl' Jlo14. hut '"rJ'IIIIIIl" nol a• dfl.•l'fi\C hl:l·au~ lht~ ('OnlafliiOanl lllU!'>I fif\1 drffu~c In the fru.-tun: .;uri'<K:~ .mil mtn rtw ''":II m<~trr\ 10 ••nkr ro '"rh. A!> a rc:o.ulr.e\cn ,:,rhm~ •·ont.anunanl' ar,· pr.•hahl)· rl'f;lll\l'l) mohlll' under lra..:run: 11•'" l'lllld111nn,.

()u;rlllalrwl~·. Jill' l'\i,trn~ informatron ''" vroundwarcr (llOtaminant mi~ratum !rom Lahnratory facilitie' agn'\'~ with lh" as<tC<ism~nt ,,f the mk ,,, lhc 8antldu:r Tuff in the unsaturated tone Thl~rc i.; evidence 1ha1 some non,orhmg o:onlaminant' ... u .. -h a' 11111um haH rravcled !tignilicant depth' through lhc unsaiUrated tone. cwn In th~ rcgrnnal alJmfcr r Rog~rs. IIJW!) durin!! the 50+ years nf Lahoralnry "Jll.'ratinn. Thi!. IS prnhahly a CltO'-CI.JUCncc of releases 10111 ,·an yon~. and transport at high pen.:olall•ln rare!> lhruugh regions where lhe Banddicr Tuff is lhm or Ill)( prl·S~nl. However. rnosl known contammalll rdl'a'~' ha\·c not lrawkd that far. and rhus ~1111 rc~idc m the uns;uuralcd mn~ l<cl~a!>c~ on mesa~. wilh low infdtralion rale'i. or ~nrptton of ,·nnraminants SUl'h as Srrnn11um anJ l.'ranium tiOin lhc Bandelier Tull. arc pwhahly the uplanatron.

,.,. In adllitum to pt<•\·iding a conlcxt for as~cssing the ri'k of l.ahoratory-dcrived groumlwmer t:nntaminatum. the result~ also provide dircl·tio~ for fuiUre unsaruratcd mnc charactcrinuinn al·tivuie~. At prl'<tCnl. there apJiears In he no need 10 emharli on a cosily and timc-t:on~uming effort to characiCtlle the lra~:turc s\·~•~m' rn thl' Bandl'licr Tuff forth~ purpt>se of pre,lirtin~ W<~ler ~rcnlation and o.:omarnrnanr uan,pon Nort• that rhts ,·ondusi•m refer!> only hlliqurd rnowrnenl lhrough the Bandelier Tuff. and dllCS not arrt~ to.,rtt.:r rnd I~JlC' of interest such as rhc Basalt unir~. and is nnt meant h• imply 1ha1 other rypcs ''' fr;t.:lun· "'1Ud1c!l arc"''' unp.>rtant and u,cful '"c characrt:rilaliPo ao.:livilics. Anolh~r implKation of the n· .. uJr, I' lhal l'POUJmlnant' released on mesa' or llll'anyons ~A·ilh 'i)!nifll'anl lhidmesse~ of Bandelier luff

r 'houiJ ~· .thk to tx· apprmunatcly mapped u~rng a ~eric' ,,f rclall\cl}' shallow. vertio.:al hnrcholl'' 111 dct•·rnun,· tlk· V\'rtrr;JI c\lcnt of rransport. Conlarninanl front' I hal arc mapped in this wa~ would prm ide informalrnn on field ~·ale infiltratum rates anti 'orpllon dwrarteri~lll'' thatl.'ould he applic\l to calihratl' mtllfcl, ol ll''"' and transptlrt. Thq would al'o provide ,onlirnMIIllO of the results prl'\t~nll~J mthts '>ludy. e ... pc.·•alh 14llh rcspcd "'l.'omlarninant lran,pnrl. Finally. ahhnugh n., .... wa~ tk•mon~lrat~d ft. ·~··ur In the Ol.lltl\. lhl\ doll'' not nlC'an lhal no\11 "ne,·e .. ,anl~ Ulllfnrm Wllhln llll' JllalriX. An in,lrum~·ntcd IIIPrlll••rint!

II

F,;f~~·. ,,;.

\·'

\~'lol4'tll ~~~~~~lflh'kolotn.J ··~·rat~·d 10 1111~ U.md&'du·• lull .,.,,ui.Jprot\'lol•· ii<IIIJIIotnllf•Hilf•trfldlltlf• ·•Ill""' J'fU~'t'"'"'4'' .tiW IOIJl<,.I,IOI lfhlflltl- H1lt1lh~· lfilll\f1ttfl ·~•h'lll ond•.~<lttl)llfK' l"lt: 11f ht:lt:fllj.'l'OCIIIP on tfh' tklmkcJ fl""' .111tl Hilll"flloln \~\IP:fll '\u.-h ol fwlll IIIH'IIJI;Jfloll -.nuJcJ laJ..-1~ tiiiJliiiH' trall'>l"tfl f'll'ofl<lu•n• .tthJ

J'hWIIk' a•lo.ltll"""''""'i.knn· "''"'' iiiOn:;nu.tl tth>~fd

lllu•. alth.ou11h IlK· u•n. h''''''" ••Ill!\' prc~·IJI •Hnh ,,,, ""' .1ppl\ ''' ""'""'""''"·'"" 011 .•II l.at><or.tl"f) , .. , • ..,, tJW t tb..,·n ill IIIII' ;trkl , ..... lllllJliiO~ 111~ Ill• ,.fdlflj.' J'l 11\l<h' ,Jfl I nlpnll,lfll J'll'f'Jll'~ II\~· nit II""' ,tn.! !r:Jfl 'P' "'

atfJrtl<~flal dt;ll"ddt'lllillto•n .ul<l fll"flllllrtlll! ''""'''· rlw rt·,uJI, •houhl '"nlrthllll'lata \llateg• '"r ''"' dh~dtH·l~ •kill IIIII '"''" man) "' rtw tr•·•un,J~ .. ,,., , . '"'·'"""·111"11 '"u'~' Jannr I h.: I.<Jhor ·''"'~

Acknowledgements

Ttm ,..,.,. .. "'·'' l'oJkiUdl'd urkl•·rthl' au,plt'l:~ ollhl' 11 S f)\•p;u111JCnl .,f Encrt!y.l.u' Al.mJo' Ernrronmt·nl.tl Rt''hiHIIIo>nl'r••l•'~-1 Tho: author' .tho w"h lolhanl.. the many s1afl nf the Ldl<•ral•lr~·., Em·tmnllll.'!ll<~l Nc,loralmn Ptntell lor fll<lll) u~:ful .. Jt ..... ·u"l""' dunnp 1hc l'uur..c ultJw, worli.. SJ>cctal lhank' vn ••• lhana Holh-. fm '"I"JlOfllll!llhl' modeling dlorl and \Ug~l.'\1101,! lhal thi'l IClll he U'il.'d 1.0 t•; .. l ttl\' ~·onn:ptual moo.lt-1 ph·~·nlt'tl mthr' 'htdy. and lo Kay BtrJ,.dl for her lhorough review ol thr., manu<o<·npl.

References Alli~nn. G.U . W .J. Slnrn:. arkl M .W Hu~hl·~. I YH:'i. Rc .. :har~c 10 kotN and dune !ocdiment:- ul a :.crm-aml

lan.J~·•tJ>c all mdKillcll hy nalural i~lhlflt'' and dlloride. J. HydruL 76. I -2ft. Bmhdl. K.H .. A.V Wolfllt'Crg. () ffolli,, T.A. Cherry. K M. B••wer. 2111111. Oruundwall'r tlu~ ;m•l

ntdsunudrde tran:o.Jlllfl ~ukulations fur a po:rformann· a,..c,Mncnl ul a low-lcvd wa•le 'llc . ./. Ctttttam. 1/I'O'YI/. in rrcss.

Br~th·ar,•.on G.S .. T .M. lbndurraga. andY .S. Wu. llJIJ7 The "lc-~ntlc unsaturalcd 1onc m£l\Jclt>l Yucca Mounl;tin. Ncvad:.•. fur lhc Viahilily A~St.·,snwm Te..:hnu:al Rl'Jll>rl I.BNL-41H7X. 1-<ti-Hen..:c Bcr~dq Nalmnall.ahoralnry. Berkeley. Ctlifornnt.

Ru~!'lnd. G Y. B.A. Rohm.,.m. U.S. V"wanalhan. (' W. Ciahlc. HJ. Turin. W.E. Lowry. 20011. tl!Jsaturah.'tl tone tran~ron IC">I. Bu,tcd Buill'. Nl'\·ada. I. I: ,,,..·rimcnlal •k!-tj!ll and licld ohSt.·nallon ... li'lltt•r Rl'vmr. Rr1 . 'uhmtltcll.

Carey. B. G. Cole. C. Ll'\\J'i. F T\31. R. W;sr;t·n. Anti (j Wnlth:Ciahncl. 1-JY'I. Rcn..cd Snc-W~tlc Cic••ln~tc M .. ltlcl fm Lu-. Alamo~ Na1u111all.ahora1ory !FYY'I). R .. ·por1 I.A-l.iR-00-20:'ifl.l.m. Alamo' Nati1mal Lahnratory.l .. u'i Alamo~. Nl'\1. Ml'll.l~o.l.

(iray, R N .. 1'197. Hydrologic hudgcl ;mal~''' and nUIIIl'll.:al ~unulalions of ground\\all't llll\'" 111 l.o' Alamo' •:anyon Ol'ar l.no; Alamo~. Nc" MI.' lit~· ... Ma~tcr'' rtll'si•. University of Nl'\\ Mo.•n•. AlhUlJU.:rquc-. New Mniw.

l.ANL ((.n .. ,\Jarno., N:11ional Lthnrah•ry). I91JX. Mit) ~~. IYYX H~dt••gl·olngrl· \Vnrkplan.J.o, AhllllU'i. Ne~ Mc~1cn

Ncwman.IJ.r> .. IIJI.>f1 Vadll'l' t<~rtl' wall'f lllllll'lllCnl at :'\rca (i.J.o, Alamt•ll N;lli••nall.ahntahlr\. TA-:'i4· lmcrprt:!:.lllon., ha-.cd on ~.:hlnndc ami \tahlc "''"'I'C protill''· '-'" Alallltl!> Nuthlllotl Lth•>rah>r~ do~unk:nli.A-lJR-'Itl--tM!:!,I.u., Alanll". Ne~ Mt:\•Cn

Nilan. JJ. and T.A Ru"h~·~·l... 11/t.JI lnfthratton nf a hqurd l'rolll 111 an UINtturatl·d. fra~·turcd J"''''u~ m~·•ltum. Wat..r Rt'.w111. Rt'l., '1.7. K. :!0911-111 ~

12

.··

~j~J· ,i·;·

Pl.'h·r,, H H unll LA 1\1;1\l'lkr. I'IKI! 1\ ~·onllnuulllm·~ll'llnr "'·'"'r IIJn\Cfll\'nl m ;m tHI\iJiurah~tllr,.,·tun·d r .. d ma''· w,,,,., Rt·lour Rt'l .. 24. \. 4tt .... uo. Jlflll.''i!o, 1\. J.S WiiOJl. ilnd Y W T"'"t!· I1NO llu thl:rlllllhytlroln!!at' ,·onlluwn' rwar lugh lt'll'i "·'•II.'

\'lllplll<•~" 10 rarr•all) \ilhJTillt~d fradiJr\'d luff I 'iiJIIUialll•n 'lUthi.'' wrlh I.'Xpllllt .. llfl\llkrall•lll "' lr;t.-rUtl' dl(!t"J,, "'"'''' Rn"'"· Rn. ~tl. 11. 12 '~' 12·1X

l'unymun. W IJ. LA l·.n)arl. a111l SCi Md.rn. I'Jill/ lhdr .. lttl/1•·, hiU,tl'll'rr~IKs ul the Banddll~r tull a' tkh~llllllll'tflhrouvh :.n IOJl'l:lion \~,t•ll ')'ll'lll. Rt•porr 1 . .1\ ll'il I-M.S. Lo~ Alamo" Narann;JI Ltnt~r <tlory. l.o, Alamo\, Nc"' Me: ~ll'tt

RohtO\IIfl. n •\. ,lfld (i Y. llU\\Ild. 21100 Rmlumudldl' lran .. pllrt lfllhc Ull~illuratcd /ttOe al Yun:a M··unr;un flUJIII.'TIGil model anu lil'lll \ith.latrcm ,,lldll.'\, (;cophy"l':JI Mono~raph I:!:' Wilhef\ptlllll Voluml:. Afil'. W;"lun~h•n. IH · .. \2\. \ \f,

Roh'""'"· B A. M WJrlo.ow~kt. C' J. Hl11111. L. I lak. ;md H Knd1. I 'J'}'I. Numen.:al modd nl llow. :mtl tran,port lor '-"' A lam('' can yon. En \'trurunc ntal Hl'\lt 11 a11on Protcl'l ll'<.:hm\: al report. l,o, !\ lanu ,., N,,,., mal Lan. •rarory. Lt" Alamos. Ne\\ Mc\ll'O

Roh'"'' 10. B A .. JI.S V 1\\1 ;mar han. and A .J. \' ah 1\.·,·hl. :'I KlO. Eflil'll'lll numerical ll'chmqUl'' f••r m••dd111g muhtcom;lonl'nl ground-w:•l•·r rran~r•~rl ha,l'd upon ~irnullilllcnus ~nlutum of 'lrnngl} ,·ouplc.J 'uh-.ch ol l'hnnKalnHnponl.'nh .. 1dl' ill Wa/a Rl'wur .. 2.1 .. l07-.U4.

Rotzl'''· I>.B. ;nul B M (jaflahcr. 19Y5. Thl· un'>aluralcd hydr:.wlic charill'lcristics of Bandelier tulf. Rcpnn I.A I ~·lfl!( Ln, Alamo~ Narinnal Lahclratury. l.o:o. Alamos. Nt:w Mexico.

Rtttzl'r'. D IL B.M (iallaher. and E.L. Void. 1'}9(). Vadose: 100c mfiltration hl~nc;tth the Paranh• plateau ill l,o, Ahtmn' Nauonal Lahnralnry. New Mexico (ieological Sol:icry Guidehook. 47'11 Annual Ftt'ld Con!Crc:ncc. Jemez Mounram' Region. 41:\-420.

Roger ... D.B .. IIJIJX lrnpacr olrntium di'l"''alon surfac.· "atcr and grnundwarcr at Lo, Alamo~ National Lahorarory thrrough 11197. Hcpon L1\- 1.~4(15-SR. Lo~ Alamo~ Nalional Lahoralttt)'. 1_.,, Alamo'>. New Mc~tl'o.

Soli. W.E. and K.H. Birdsell. 11NH. The mllul'lll'l' ofn•atmgs itnd filh on llow in fractured. un,arurated porouo; med1a !'.ystcms. Wafer Rt'III/If RF' .. '4. 1. 11n. 20~

1\cng. P.H. ;md G.A. Zyvoltl\kl. 2000. A rc:dU\'CO dq!n.'c of frl'l'dl'm mt:lhod for simulatlllg nnn."otherrnal mulrt·ph;"l' flow •n "porou' mt:diurn. ,\dnm. in Watt·t· Rn,ur . .:! '· 7' I· 745.

van Gl·nu.:htl'n. M.T.. IYXO. 1\ doscd.forrn -.olutinn for prl'dJding lht· h)'llraulic t'onducll\il~ ol un,aturatctl soils. Soil Snt'llce Soc of tlnwr. J .. 44. XY~-!\11!1.

Vi~wanalhan. H S., B.A. Rohmson. A.J. Valorl'hi. and I. Tnay. Nn\. JIIYX. A rcactivl' tnui'J'''" modd ,,f ncptumurn tlllgtalion from the pntcniJal rcpn~Hor~ at Yun:a Mountam, J. Hydro/.. 204. 251-2MH.

Viswanathan. H.S .. fl. Y. Bu,!'>nd, B.A. Rohinst.m and H.J. Turin. 2000. Un~uturatcd wnc transport ll'st. Bu!'>ll'd Aullc. Nnada: 2. Modl'l dl·vrlopml'lll and ~·ompanson to field data. Wain Rt·.wur Rf'.f., '>llhfllllh:d.

Zpoltl';lo. {j. IIJX.'. hnlll' cknwnlmclhnth fnr !!l'••lhl'rrn;tl fl',l'l\1111' 'IIIIUiation./nl. 1. ,'liumcr. oltld Anoll\'1. Melh. 111 Cieomnh.. 7. 75-Xtl.

Zy\'olo .. kt. G .i\ .. B.A. Roh1n~un. Z.V. l>a~h. and I.. I.. I tl.'a\1.', IIJ'I7 . .Summary of thl' Jntlt!cl-. and nk•tht~tl' for rhc FEHI\1 applll·ation- A fimlt~·l'knwnt hear and ma~'·ll·an~lcr l:l•lk. Report I.A·I :no7. MS. Lu" Alamo' !\latJOnal Lahoratnry. J.,J, Alamo ... Nl'w Mcx~eo

List of Figures

Figure I. Cunr,•ptual rnc1dd for grounJwatl'r Jl,,\~ ,,nth1· l'iiJitriro Plalcau. Fr11111 LAN I. t 194li 1.

l.l

haUII'I.' 2 I .. ,,.,."""' t~l '"'''•'ttt~n llntf montfnlln:f! "AdJ., lor th~· un .. iltllfall'tl/lliW IOJ\'\'ttiln ... ,, hom f'unymun t'l 411 II'INYI

hi!Ufl' 4 Mt•a,ur.·d fl••" ··•tlliltttnn' dunnv th~ Ull\.aturat••tl /nnt• lflJI:ltoon t~'tiSIIc 2. 'f c:"' I "' PurtHflun cl ul.. IYIIIII ottll.lv.OhHk IOJC<'IIon rrl'"Uh' Vl'f\U\ tlllll' "' lttJl'l'IIIIO 11m~· rate Vl'P•U~ tlllk.' ... ' ( IJffilllillfH.' ma~' of OA·all't • ntco.:·k•l •fur tnJ,Yth<~ tnt

l:t~Uil: ~ C'oruh•ur' nl water \'1101\'0it'on .. lruo.:te•f from the n•·utron ln11 data durinl! and ;1ftcr the injl'clion lc'>l. loall.>:t\ 7 aft,·r lllJ<.OO.:tmn. lhtl>ay 211; I\' I Day '1:'1. t.ltl>ay HI} f('lld olmjl'~linn phil'K'J: let Day l27 fJ'II)!'tf·mtcd•"" Jlha""CI. t:rurn Punymun cl al. ( IIJI'I'-1)

h~urc fl. ~Urlk'TKal gnd u~·d 111 the !>llnulathlfl~ of tht· tnJn·uon tnl. 'howm11 the ro.:~.,oluuon and 11~ h~eatton ''' th,· IOJl'dton 1ntcnaf a) Top \·icw. hJ Stdc "''" n Pcr!>pl'o.:tivt• \'Jew

h}lurc 1 Tv.·•·dllncn\lon<Jicro\' ..cclinn~ through the model lor vano'" time~ durin,g the mjt'dton tc'l lunclo corr'''~"'"tl h• tho"' .tt whidt rh~· ern" -.co:tton' of F•rur~· :'i wen: prcpan:d.

List of Tables

Tahle 2. Cnmparasnn of rnnJcl and dala for the nugratmn rate' of the wakr plume.

14

'II

.L

CJ Qn:lokrTllf

CJ 1\¥!~ -O!rotad!l ~lllllao

CJ Sot.,,"" ()a.(>

CJ T~~

.. --- ~ ---..... _ --;- .. -;::~~· ...... -.....

.a High infiltralion

Figure 1. Conceptus/ model for groundwater flow on the Pajarlto Plateau. From LANL (1998).

15

111·2 0

N·l 0

lnjolcQJn •­... 1-o SE-3

SW·I

e

S·l

0

10

NE·I

0

SE·I 0

SCAU: 0

LEGEND !!!.! • ~ ;i:.JDn ... I e Obeetvt~lDn ~~o~e.

re.!Jiand2; ln~wel,l8113

0 Obeerv_....... hole

1011

SE·2 0

Figure 2. Locations of Injection and monitoring wells for the unsaturated zone injection test. From Purtymun et al. (1989).

16

'II

. ;

. ,

Figure 3. Injection system used in the unsaturated zone injection test.

17

,-.:.·

~··

.>, . ~) '

i 0.18 •

i .. 0.17 :"'· ••

0.16 .. • •

~'l' ; /. •·•·•

Injection PniSiure for Site 2, Teal 1

• • • . ..... - .......... filM

(a)

• v ..I-. i 0.15

0.14 ~.,.._..,..,,_..,....-y-..,.....~~....,..,..'T'"'T ........ ...,..... ................. ~"""'"'T"""" ......... ,....,.,.,.....oor""' ........ ~ - 0 10 20 30 40 50 60 70 80 90 Elapsed Time, days

Injection Rate for Site 2, Test 1 0.4.,.-----------------------..

' .. 0.3 i I o.2 c: .st l 0.1 .5

·. _ .. ...... . •

·" .... • • • .. . ' • •• • ..

• •

(b)

• .... .._. ' 0.0 ~~...,...""'"".....,.,~"""",......,.~"Tn"l' ......... ""··.,.,.. ............. .,..,..,..........,..,....,.""""..,...,.... .......... ........,.. ,,....,...,~ 0 10 20 30 40 50 60 70 80 90

Elapsed Time, days

! ~

Cumulative Water Injection for Site 2, Test 1 1.5&+06

~ • - --· i 1.0e+06 •• • -""" - .,.

(c) i .... c .. 5.0e+05 / ~ ,. .!! L--- .,. I O.Oe+OO ., ., = 0 10 20 30 40 50 60 70 JJO 90 u

Elapsed Time, days .,..

Figure 4. Measured flow conditions during the unsaturated zone Injection test (Site 2, Test 1 of Purtymun eta/., 1989). a) Downhole Injection pressur• versus time. b) Injection flow rate versus time. c) Cumulative mass of water injected during the test

18

I II

'. i .. Ill.-.

(a} (h) (CJ (d)

......... "·'"' ......,.,.,,.,, ...

CROSS SECTION (ft)

(e) May9, 11166

/ CROSS SECTION (It)

' Figure 5. Coutours of water content constructed from the neutron log data during and after the Injection test. (a) Day 7 after Injection; (b) Day 29; (c) Day 56; {d) Day 89 (end of Injection phase); (e) Day 327 (post-Injection phase). From Purtymun et al. (1989).

19

·I .·

. . g .-.• ·;, 't)- ,j',zM•~i:1:\•~b~i[;;J.ll)i~;~~.'~\kc~i:;\il*.i~~~iiii::&1\r:ili(';-' ··~}>.?)~l\~1i&ldi<:1?,tll;t~~~H!fi;>· ,.,.;; :L;t!::.) "''·'"·''',;r,.-~ilq4.k~'f

.. '.,.,,,

..... ~·~··

50m

lnlc'<ltnn l'oml • . ' Qbt3

.: ...,-.. ~ .. -..... ..,...... ..... -~4~~ • . . .._ ....... ~ ...

· .. ;

+---+ 1 1~-. . ... ..

Top ·r~·-~ 21 ()() m- '----~i-"1: ·,...· ___ _,

• J e

30

Figure 6. Numerical grid used in the simulations of the injection test, showing the resolution and the location of the injection interval. a) Top view. b) Side view. c) Perspective view.

20

Qbt2

,, ··:

(a)

ss

70m

(b) (C)

July 16, 196S Ausustll. 1965

(e)

Day 327 May9,1%6

Post-injection phase

(d)

~pile ll'ftr I 4. 196..'1 f'.nd of injection Jlh-

Figure 7. Two-dimensions/ cross sections through the model for various time• during the Injection test. Times correspond to those at which the cro•• •ectlon• of Figure 6 were prepared.

21

[,.,

.

.

',,.

Table 1. Hydrogeologic propertlee: u1ted In the model for the aub-untt• of the T•hlrege Member

Data S(JUn;c: Rul!cr' and Gallalwr I 1995)

22

I II

Table 2. Comparison of model and data for the migration rates of the water plume ! ··---- . ·; verti~i-·M"ov~menr ~r-s-c«,·<~orii~ur-1

.. Q~-'~- ..... .. .. i . .. . _____ ..(~4-~YL .. . ___ . _____ j ; ______ fr~t.~----· _ _ ~---- ______ I~-- _ .l .... _ J~-~-~ ------- ··t··· -.... !\'~-~· ---- ~ 06-17-65 06-24-6:; 1.2 ' 1.4 l 1·- ------------ --· ····--- •. ··----··· ·i· .. - . ···-- ---·········-··· ... - • ··-····· --- .... -·-· ..... ··--··- ---+- -.... ----- ....... ·--- --- . ---1 : 06-24-65 ~ 10-25-65 ·0.24 10.19 I r-·· --lt)--25~(;5 ....... t .. - i-i-=19~65 --- i c):f_r·· ------ .. "l(j_()~<i" ·--------- -- ----1 ·-·-··-----.-- .... - ---- .. .. ....... .. --· . ---- ·····-··-·'"- .. -- ·• ....... ····- .... --------------·t·····---· ............. -. ------- . ·-1 t=:~~i~!i:i;}~ -r. ~~zt~; · :1 :~:f~t ~::~=:=t~~~: :: ~=--=j L----- ·--- - ............. ---- -- . ------ --- .. . . ----- -·------------ ---------------- ----- -- -· ----~ :

Jlorizon~l Movement l ,

I ~ : Date · (m/dav) i

:----------··- -·--·----···-·-·r-----------------·--·-·· ............ J ·-----···------------ ----· -,-::J ________________________ -! ~----·---.f_!o~------4-------------!~-----·- ___ j ___ ... c:c_~Q~~------t---------~----MO!!~~- -----1 06-17-65 : 07-16-65 . 0.24 1 0.2H : :--·-------- ......... ·--- ------··f ------------------· ------ ·------- .. ------- -----------t----- ..... ----- --·- --------------~ ~--07~1_~--:~~-------~---·--08-l _ _!:il_:~------~- -- ·---QJ_? _____ +--------- 9.:Q:! --------~ l 08-1 J -6~---~--- 09:!._4_~~-------~-- ---~~.:QQ!_ ____ +---------O.Q} _________ i ! 09-14-65 I I I -19-65 I 0.030 I 0.08 l ·--- ··--- .... ---- ·-···-- ----- .... _, ___ .. ---------------·· ---- ·- ---- ..... .. ... ------ ---·-·-··----·--r-·-----------· ·-- ------ ..... ----· ·--~ ; I I -19-65 I 05-09-66 ! 0.061 I 0 I ~------····-·-··-----~---~---~-£-.----- -----------------···-···-J...·-··--·~---------------------··___1_·--------··--··--~--------------f---- ---····-····----·-·---------- .. ------------- . --------,---------- .... -------- ------------ ------· -· I

j Upward Movement (m above i ; ____ ··---- ______ _injectio~~lntl ________ _ : ~~ I ~~ ! M~cl t----···--··· ----- ··-·· ···-····------------------ ---·. -------·- ~ .. ·-----------------------r---------------------1 09-14-65 1 4.3 : 8 r ----- ----~--.~-------·------------~--- - ·-· -----·-·t--··- · ------------------~---~-------------------------' 05-09-66 ' i 7 ' 10 l-------······· ..... --·-··· --------------------. -·-- -· . ----··· --- ......... ·········· .... ___________ .J_____________ --·· --------