Territory Stories

East Alligator district centre water supply assessment : Kakadu National Park



East Alligator district centre water supply assessment : Kakadu National Park

Other title

D . Pidsley


Jamieson, M.; Pidsley, D.; Paiva, Jerome


E-Publications; E-Books; PublicationNT; Technical Report ; 26/1991




Made available via the Publications (Legal Deposit) Act 2004 (NT).






Water-supply -- Northern Territory -- Kakadu National Park; Groundwater -- Northern Territory -- Kakadu National Park; Kakadu National Park (N.T.)

Publisher name

Power and Water Authority

Place of publication



Technical Report ; 26/1991


1 v. : ill., maps ; 30 cm.

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Check within Publication or with content Publisher.

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Technical Report WRD91026 Viewed at 15:07:48 on 29/07/2010 Page 102 of 107. !llcn ::ers ll~ steel. snait.:::;r ;'X)I...i.ldec .:-.1bt;e!;" splders~ 3S tushes~ chcate plated J16 SS caters -ard coated. steel ""i""sln;S~ D.le to cotrc:s ion of t.+te GS co.lu:t:1. in oldsr ':'ns~.:ll.la.t:ions it was camcn for the ;;:::\F.QS to drcp 1:0 the bott.::m of Cores. Purms unable :0 l:e ex-crac::ed. r:esttic:t:.ed Ela..s and" interiereci wit..~ ::'E!91acement fllllI9 settin;s. ffiP columns and 5S wire rcpes to the ~ have eliminated. t..+'lis prcblan. Ga~erally Scut..'1ern Cross squatte:t tarl:.s are used. SaNever, it has been fowx:l tr.at ;llain galvanized L-on (GI) tan;;s COrrc:x:2 alt: in at:a..lt 5 years. To overcare this problem l:he'!' are new wilt of o.tam hot dip CiS sheet. "..n.r.h Mar,tiplate bonded both sides an::i neoprene ~!bber sealed. joints. Internal hot dipped GS an;l! bracirx;; and. roof suP;;:Cr""<-5 are used. Failed plain GI tanks are l:eing S'..lCcessfully relined with fibreglass and p:'Ilyu.""'eti:lane. A spirally ....-cund PRP ta.nk at Qmbalanya (Cer..pelli) is g.l.'ITl.rg' gocd service. FRP pareL I:ype tanks have recentiy teen installe<! at Raminginin; and Angurtlg",.l. 4.4 '!r.m!Jfer l't:aQs Cast iron (CI) hcusi.r.gs and SS st"'.aff:s CI iIIQellets give reasonable ser'Jic:e :=ee bronze and SS are superior .. ",.5 Re:t=inzla:t:icn Pipes: are used .. rut zi.'1C In the ol~r systems GI pipiIlJ was used ...nich suffered seve...--e tute.ro.Ua.tion. water quality detetiorated due to suspenCed and dissol ~ iron co=ion produc .... s am press"""" dt cpped due to res tricted pipe Cores .. Asbestcs cement (.AC) pipes have teen .tSed in many localities. An inc=easinJ rur.ber .:: cases of severe lead'li.n:] of the caDent frcm. the 'otIalJ.s is occurring (Pigure 3). Minj ilan; AC retiCJlaticn ~ipes ~risin;; generally 15iltm dia. Class D installed sane a yeats ago have Ul1d:!rgone majol:' leami.rlJ failure. In n:any cases the v.Ul has t:een reduced 25t in t."'lid::ness arxi has t..~e texture (:f saturated. cardbca.rd. '!he v.Ul StIer.gth has teen reduced to the extent that new fittin;s cannct be cut-in. A check cf the fibre conte.''lt of two ba:lly affected supplies has sl".cwn that the total fibre content fran all SOJrCes, oot: only asbestos cement attack., to be less than ooe !:enth of the mo limit (D>oartn2nt of Trans!'Ort and lilotKs, 1984). . C! and MS concrete lined fittin:;s have teen used with CI, AC, MS and b01yvinyl chlC:lride {~) pipes t:u t failures have not been !'e;IOrted .. fur the rrore t"E!I'Ote catlIl'l..lOities PVC pipes have been used a.llrost exclusively in recent year.s because of t."1eir ease of t.."'"artSoor!:acion and . hardlil"'lg. NcJ corrcs ion of t:.1-teSe pipes has occ....orred or is expected. o , , 20 rnrn ! ~-.. ~~;:":-,?~~~.T:"' .. i..~ ~:..._~: _~-: ,;~~ ... _ .~~:.. -,..;~ -~~.. "'.". __ c .. - - ' ..... .,.- ... - -~""--- ~ ~ ~.. --" "'~>:' . .........---.. --. .. ~ .. , , l!'igure 3 Section cC .AC pipe wall frail lIlu1unb.ty shcwin;j leacnin;J 4.5 Bcuse PlumbiBJ Corn:sicn PhefXlD=ma Ole eft"ect of the GI~ AC a.rx1 concrete li...ed fitti."'t;S has been the reeu.cticn of aggressiveness of the wat.er on passcqe th....--cugh the reticulation due to reaction ... it.i-], the pipe IM.terials. '!his has resulted in a ;::-educ+'~on of t.o.:e acidity and increase in calcium car=on.ate content of the water enterirq hOJSe plumbing systems with a cons;e:ruent =eduction in the ccpper and. brass plumbing con'CSion failure !:ate. !.."1t.."""'Oduction of P\C retiOJlation pi;es has resulted in virtually no reduction in corrcsivity fran bore to hOJSe, t..~ aggravatirq the plunbirq corrcsion problem~ An exam:>le of t.."is OCc:..IrreC at:. Wadeye (Fort Keats) where due to lOil{ ~t.e!." ;tressure in the old GI/AC retict!lation system a pvc rin:; rrain ....-as i .... .stalled.. Within 6 m:m1:hs of the r!.!'" installation coinc idenl: failu_'s of o:::Qper hOJSe services occurred althaJgh they had given satisfactory 5e!"Vice fer sore years. '!'he hc:soital was ccnnec::;ed. bebieen t.'1e old and new' lines and the section fed by t."'l.e GI/AC reticulation had c:c:ooe~ levels Of less I:han 0 .. 5 mg/!. Ioohereas the seC+-'; on fed by the new p\it: main had. cq;:lper levels up to 12 mq/L {Allen .. 1981). '!he classical m:::x:e of t:ai.lure of hO.!Se pll..l!lbing is :irs1:1v -a corrcsion incuced leak. in ~,e solar hot "later se:t:\.<"ice (h"WS) " f:bt a.cidic watez:le.a.io:i:q onto:.he CtXlt sneeti:-q then quidcly eats thrcuqn allowing t..~e '...ater into t...'le ceilil"'q space