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.

File type


Copyright owner

Check within Publication or with content Publisher.

Parent handle


Citation address


Page content

Technical Report WRD91026 Viewed at 15:07:48 on 29/07/2010 Page 105 of 107. 4a a Bo1:. 'Wat:e2:' Services !V!r. :renticned pr-eYicusly t."'. r8t)id f.1ilure of hl?e 'Nater services (HWS) has been cot! of t.."1.. %MJ.n <:3.l""" of _",:"i"'" damage to t:ui!din;s ar< .... ing fraa t.'1e corroslV'e 'Alters. c:evelq:r.lent of COL ... caiat electric HWl has been maruf~c=urer:s. resistant solar one! ;ivun over to the SOlarhart h ...... a jadceted solar unit (Hodel JD) in .nidi the fluid recir<:ulatin~ in th" collec"..cr is separated fran the .... ter tein:; heated. It uses .. heat ""ciWl<;/er jad<et: to heat the ... tar. '!he axdlarger storage tan< bas a. vi~ .. ...,.,1 linin; and. .PB inserts to pz:otec1:. the o:::tUii&\..~a1S frcm. coucsicn. '!he tan< is fitted with a sacrificial ancde for additicno.l .,rotec'"...ion t:ut it is unlikely to be effecti". Ole to t!'8 101 cor.duct:ivity of the water. TheetaNIX h<M!t solsr units wit.'> aU <:aIQOnents in ccntact with: t..'1e water made 0:: SS. 'lhe solar eollsct.or COIQrlses a !1Jl!lber of heavy dlty ""aJlJIl tubtts .nich evaporate a heating fluid raciraJlsting thrc.Igh SS COl-.:lensets in the stor_ tank. Corrcsicn resistance is """"llent an; the units ""rfom well. Beasley haw dewlcped 4 full.y SS solar unit which is not yet in prodlction t:ut appeam to offer excellent ;xJtentlal. care has to be taken in the ... lEction of elec'"..ric b:x:ster haatin; elements for the solar units to -ensure catI:Iat:ibility with !:he o:::u":l:t::Sive water. A rumer of satisfactory elEl!1!!lts is available. Approadles haw been mode [:0 electric !lWS marufacturets to dewlq> suitaJ,l" units l:ut no interest is being shewn. 5. _"mFA1lIEN'l' = carri_ cut sodiUll hyd,:oxide dosing to neutralize the acidity in the JC'int Alyangula and Angunlqu supply en =,. Eylandl:. l1'l:I::m the aspect of =_csivity in relation to """"",r and brass, this tl:ea_nt 15 only partially effective because the water has virtually no ca (refer T.1bJ.e Xl an; deposition of a protective caco1 filill wculd net be pcssible (J\I!Iocican lioter li>r:k3 Association. 19781. Slaked lime dosing was at~ted 5aD8 10 yeats ar;o at Maniogrida l:ut was disc:ontirued due ta the difficulty' of cperating one! maintaining equi\JDl!nt in the remte location. Becar_ of the ~. diffiaJlt.ies of mann.i.ng" cperat:.ioo,. maintenance and ucnit.orinq of d'1emical d::sinJ plan:ts in r.note ca:mmities, many inac:essible by road for sane six aDlths of the year" the trea.i::m3nt. altemati"" has not been adq;>ted. A further diffiaJlty with bi"",,::onate dosing is the .""aU flews to be t...",.ted erupled with the relatively SlMll dose ra::r"lired to QX1diticn ttl'!! 'iff'ater to a ncn-corrc:sive state", OVer-.:1csing generally l:'eSults in scalirg tendencies with its associated problems. A l'1.Irnber ot. CQ't9anies are otferl.rq r1tllUtr31i2in; fill:ers containitrJ a ncn-tc:U.c :':'I!dia,-...t\u::h dissoives into t."le passin; HOI. ~e ulats are specifically desiqned to adjust pH and t.~e oicarb:mata level to re~r t.-"" w,atar: ncnCOrroslve to o::pper .. brass. N:. and centne lined fittil"qs. 'l:\ey ""'!Uire badc ..... hiog an; tIOq.Ii.ar replenishmtnt of the :nodia. Althc:u;h 11>JCh sUt>ler than llmt dcsing plants. they still require a ocnsiderabJ.e degree of aaintenilllce and do net. provide a CC)nstant dee in; conoent:."atlal with ~rying t!!.0\JIIS. No neut..~izinq fil!:a.r:s have been ir.stalled to datel:>1t they dc, offer a relatiwly ~etical altarnati'''' 'or consideration in special ciro.ms tances .. 5.2 Aeraticn Aeration was tried at Manin;rida and Galiwinku for a short ti.>ra and is used at ~t11untuy by Nabaico. !t appeaz:s to in""""" .. the pH by O.S to 1.5 units. For e.X'aIf91e at !tI.ulunbJ.y Ean assisted updrau;ht aeration results in the pa risir.q fran approxi."t1a.tely 5 .. 4 to 6.8 ar.d a reeuct:Lon of the free CO2 fran 44 to 3 m:;/t. (!l:;an. 19841. Aeration is not. prq::osed tor t.'e supplies at t.'lis stage l:ut :nay be adcpted in the :utur.. in o,,?"r to raise the pH to within the OJrrent Aus-trall.aIl J:epartrnent of Health desiral>le ro.nQO of pH 6.S to 9.2. Int...-cdJction of aeration WOJld involve .replac-enent or enlargerent cf exiscinq bore or transfer ~s Ole to the additional heads .. or int-'""Odu~ion of aer3.ticn u .. ,its ~lete with lift p~s. Considerable capital and extra cperating exper-,se would be involved in either casra. 6. = or (DI!R)SIaI m:lULllal Upgrading the ccr=osion l:'eS.btartce ?f bore PlmQS, casin;;s.. screens and col.uIms .has lnOlrred 7:'1?-"'"3. capit.al ccsts. Hc:7Never .. the ~roved dura~J1.uty of the carponents wculd have probably' ,,"ud off even if the groundwaters had been :-egarded as non-aqgressive. t:urable corrosion protection of tanks ~ a.l~s relatively expensiV1l!',. and a cost penalty 15 be~ incurred in this !gard for the coastal supplles because of the .. xt.. ....... conditions. SUbstituting ~ Eor 1, ore.. CIa. and ~a. retiOJlation ~i;es has incu..'"1:ai no cost penaltle5 because of ~a.rable or lcwer material and transport prices. In the case of r.aJ5e plu:nbing PB pi"" Olrrentiy costs abcut !:he same as CCQPer. HowEr\;>er, a noma L holse can be plumbed in abcu t .2 ho..trs in PB t:ut takes S to 9 ha1rs in ccpper. Also in the case of PB with c::::apressicn fittirgs, a'11Y:' two shifters and a pair of side Q1tters are :'EqUl.red .. whereas gas bott.les, ~iprent for solderin;, flari~ and cu.tti~ pipe, plus nt.tmeraJS other tools are needed for ccpper ~ CUrrently plL.l'!\Oirq new hcuses in PB o:st:.s abaJt t.'e same as convent.ional. Hc:wever, ccst savings are I!xpected as the material becares more accepted. Whe:-e hcuses are beir:g :-enabilitated, costs of !;JIL.~ir.q in ?S are substantially less than with