SALINITY ASSESSMENT WITH HARSD: LITTLE RIVER CATCHMENT, NSW
5 W Davies, D Pollock, W A Milne-Home, R B Salama
Abstract recognises the Importance of salinity in domains which are expected to operate the region .i n d in 1998 a joint uniquely and li.iv« similar aqu ifc r The HAIl ..SD method (f-hdro- commitment to develop a planning properties and re c harge / disc h ar g c geomorphic Analysis of Regional Spatial framework fl)r the future management of behaviour. Data) was applied lor salinity assessment salinity was established with the of the 1,075 km2 Little River Catchment, • Generation of a Hydralllic Head SII~f;l(e Department of Land and Water Macquarie Valley, NSW. Automated (HHS) that uses two alternative hydro- Conservation (DL WC). terrain classification was performed using geological techniques. In the first a 25 m resolution Digital Elevation Model The currcnt study was initiated technique a least-squares regression IS (DEM) and potential groundwater through DL WC Project HydroltJgic WATER OCTOBER 2001 37 GROUNDWATER AND SALINISATION The mean elevation is .+47 m. Stratigraphic sequences in the Orogen The terrain is characterised by have sustained several deformation eh'nts undulating and hilly landform resulting in the formation of meridional with break of slope features structural packages typified by intense .lcvelopcd at all elcv.itious. folding and multiple thrust sheets. The The mean and nU-:1111U111 intense fracturing has promoted the 38 WATER OCTOBER 2001 w !----- 1,'h"I""y, vet Ill.II11Llll1l',1 It, 11l<1c'}'C'Il- Table 1. Regression results used to generate the regional groundwater surface at ,L':I,,',: nou: l'k\·:ltinll. l u,: ,itT'l' ~rid \\'~l\ Little River from SWL Elevation v's Surface Elevation for Minimum Slope Classes rn'I."\lric,d hv ,\}'ph'lll" ,I or> thc' mc.iu (DLWC data, Pipe-1 data, 1920 to 2000, Major Spikes Removed), ,Iul'c' (2.')(,") .ondu iou .md "lll,d",,- "I \1 irl: the' l'c",I."'lli !,I,'I .uion "rlt! Minimum Slope Category General Morphology R-Squared Linear Regression Formula 'r, ,,11Ic'c' ",,_:Ill 11(, l 0,00 - 0,09* Morass 09975 Prediction of the Hydraulic Head 009 - 0,19 Flats - 1 0,7525 Surface (HHS) 019 - 0,35 Flats - 2 0,9909 I itt' rC'~I"ILJi III IS Il)[ , u t l.: 1'-11"1 II," 0,35 - 0.50 Flats - 3 0.9970 ,'"I\m'lICln! 1I"1\~ (;IS '1I\t! hn!n>l",,\c,d 0,50 - 0,80 V,Gently Inclined - 1 0,9978 ;1 hId..; (ll] "p.lr-';l'. 11TL'~Li li'l\ -,It'trlhlltl,'I,J 0,80 - 1.11 ~lq),,-'-l ~rulllld\\"ltl'r k\i."j ,IJLI. (lh"Cr\'l,d V,Gently Inclined - 2 0,9939 ill l'l)rl',\ ~")l'lll'rLltill~ \lln'!,'l,tl .Iqlltt-lT\, 1.11- 2,00 Gently Inclined 0,9974 c x r r.ur e d tro u: the ClIIT,'I1t 1)1 \VC > 2.00 All steeper slopes 0.9966 I lllhh,,) hur"h"k d.u.u: 1",' rill" }'rJI\L\ry (degrees) d,lLl\l't rl'prL'\l'llts .ui i'il) \'l'Jr O!'hI...T\',ltl()11 *This category has insufficient data for reliable regression, The R-squared value and formula used 1'"Tltld trom It)21) tl' .21"1!1 ,'\11 CkrJ\'l'cl here is taken from the global regression performed on tile combined minimum slope classes, [I'po"r"phil' \,mablc" IInl' .utribur.-d to ------bore point- III CIS, l m c.u rc~re"IOI\ .m.ilvsi-, \I',,, sl"ieetc'd 11\ prdl.'rellLT III till' d.u.r) 1I','r,' ldc'lltitied .u tim sta~c' .md nu.ubcr of 'lLll"'"~:tcodl'. dhtrlbllll'll hor,', IICU .ippro.nh f'lI IIHS ,'"mtrllctlOll r,'llwled Iroru the pr\l\\.\r\' dat.ib.rsc. IIllllld UpUlllh,' r,',ulh, dlle' to invutfuic nr hor,'hok d.u.r wit luu lmc.ir rc~re,"OIl, werc' dn'e1opcd tor the Satisl:IClOr\' rC',lIlt, II ,'r,' ohr,llll"d 'l'\Tral HCU\ T!»: rvl.itio nxlup betll,'cll c'I~ht minirnum slope cL",es wirb ir. the tro m linear r~~grt''''do!l\ [l.'\ul1g the:' elevation. slope' .md 1I,\ttT kH'1 11'.1' u rvcs- [1)211 to 2(1(111dataset 11\ additio n to til'e prc'dieted HHS (,\t bur" pornrs) \' tig;ltcd using: rcmpor.rl subsets l1Sill~ five regre"ioll ob,erved SWI's (r2 = lit)) (F\g, 21 rypes • Pw = Z - (k*S) Eqll,llion (,,-t (S,t1C\I\U Results however. lI'erc' !C-" s;\ti,t:lctorv Illr These v.uiatio ns were examined to ct n!.. 10%) Deptl: to HHS 1'\ Depth to Bore SWL determine the most appropriate time Residuals were mull tl)r d,ll" from bOlTS Where: frame .ind best regression formulas to in areas of low ,lope, but showed PII Local hvdr.ru lir he.id e lev.u io n apply to the elevation grid during gener- increasing varrauon with incrc.isiru; slope Z Surface Elevation ation of the HHS, The parent, pipe-T, While variability \I'as minimised withi» S Minimum Slope 1')20 to 20(111 (major spikes removed) smaller, more recenr data subsets (c.g. k A constant derived bv calibration dataset w.is selected for HHS construction I')')() to 2()()O), the trend remained ll1 the with the observed standing water level .1S linc.u regression results for minimum d.ita and regression formulas and r2 v.iluc« (SWL) in bores slope I,la"es within smaller temporal changed onlv slighrl'., The constant 'k ' \I'a, dcrive d troru subsets were In many cases affeeted by Potential Discharge elcvacion and obscrvcd bore water level, imllfficiellt data, Best rl'~ression results Mapped saline site pulv"ons lIerc used bv rearranging the above formul.i to: wer« obtained trorn this dataset using to ((lI1/.:ic-(1I1 topogr.iphi« .irt riburc dolta,et, • k (Z - Pw) / S = lio re SWL v's SurC\cc' Elevarion, ro cx.munc Sl~llCltUrC, a"m'latcd wir l: Where: l'w = Aetll,d S \V l clcv.rtiou (In R t'['JessiOll fo rm u L1S for indi vidual arc'a, of knowu grc,ulldll',lter dhch"rgc, bores) muumurn ,I"pe c1.1sses IH'IT then applied This was based on the a,-;lIJllptlon th.u The kvnlues were sorted and their to the elevation ~rid to generate the HHS saline sites represent arcas where grollnd- r.-l.u ionvhip to t0f'u~L\phic art nbutc-, (T.\bk I), In ,I more ideal situation. w.u cr IS effl.'cti\'t'1v III CUllta,t wu l: the' cx.uniucd. It WOl' fuund rh.ir k-v.rluc , "nlun,!lI'.1ter levels taken over ,\ vcrv 'lIrt:lce R.csulr I11SW"r.Ull' ,Ill)\\ that formed detlillte "rouf" WIth n.u urul short time tr.un« rro m a sutfic icnr ,a!\lll' SIte, gennallv o.cur vvirh in ,\rl'," hreaks th.rr correLtt"d he'l whcr, ininunuiu hrl',lk u[",lup" with minimum slope, EIght, IS ks-; than l .u" .uid prutik fi n e lv-d ividrd 1\l\\lIJ\llllll c u r v.i r u r e 1\ >--(),II:;" ,luI'" cb"cs vv crc ,''[,\h- 600 (dUIUI11,111II\ «o u c a vc lishcd on the baSI, uf thc'sc l11orpholugy) , k-v.ilnc breaks, The k-I,r111l" = :;.()O The prnhCl"d II HS "nd II crc avcragl'd for ",Ich was then subtr.ur.d trorn the' Jllll\IIllUIll slope "Lts, .iud -'" ~ 400 l'1t'\·~lti()11 grt\..l L1";111~ I1L11"' t""d \11 the urJglll.t1 fUrll\ ut' algebLI [(l gl'lll'Llll' rh,' I ),'pth t hc "LjlL\tioll t o de'rll'e I'll' r o H HS "rid ['utc'llt!.11 1,1]('\1 reprnl'Il[lll~ Ih,' dischar",' ,UT,l' We'r,' ,ktll\"d I' rr rI i c t l' d I I H S ,I 1 = 20(j by COlllhilllng llt'~;l!i\·l.' 1"l'\tl1h bOi ,:llOln) ::0 ::0 ::0 ::0 ::0 ::0 ::0 nom Ih,' I )q'rh to III 1\ gnd ::0 ::0 c-. lk\"ltiOII 1'\''1,111.11, \\,Tl' -, -r " - c vvit h r h.. ...;.tlt \l~IL\rll! ,"(llllh· <.; \I' !{ \..!-') \ :~'d hv \lIhlLllllll::....': l L Elc va t i o n i 11 ore S I m I tiol" ollrllll,',1 r1,(), u.. I': ' 11 f II 1\ l,ln,l; i, " It,d l'"rillLI[l'll ~'()(l'llrl I i'" ILlr~l' t I , I "b"'I"I"d \\ 11,'1 1_' Figure 2. line ar R",~I'SSIOIl for HHS Elel,iiull (ill) v's SWL 11":,1 \\: r l: III I I .: 1Id .: I [I ()II 1 ,\\,11 -r k,' Elevation 111 Bores \:111 DLWC data 1920 to 2000, PlP0 1. \..',1[,'\\111;: " tl lcd" 1 r . kIll' ,i \':\1·\) \ I ~ I i 1 im.u c: \ (\ Spikes Removed I E)' 4 POints I, I hi, ,lrll ~'''''llJlld, ~I \() ~") WATER OCTOBER 2001 39 GROUNDWATER AND SALINISATION krn-' when the critical groundwater depth levels taken over an 80 year penod fr0111 GrOllll~h\';1tL'r nL1I1;l~:CIl1t:nt, Univcrvirv ot is relaxed to within 2 rn of surface. A 1920 to :.JUDO.Regression Iormu hs were Tcchnologv. Sydncy (Unpublished). Davies. S.\V (::>(1111) }1)'d",~(colllo'7'IIi( ,-Ilid/)'.Iis/', companson of the potential discharge map derived for eight finely-divided slope S,"illil)' ,\!'"I"XClIlCIl[ ill tlrc Little Ril'C1 with known salt sites shows reasonably categones and applied to the elevation grid ClI(II 11/[') II , C'pper .\I<1('I,,,,ric V,Ji/L')', .\"SJ [. good correlation in the southern part of to construct the regional scale ground- M.Sc. Project Report, National Centre tor the catchment, but less so elsewhere. water surface. The predicted HHS Groundwater M3nJgenlcnt, University of Although the potential discharge map is compared satisfactorily against observed Technology. Sydney (Unpublished). regarded JS 'approximate', the results groundwater levels (1'-' = 0.99). Residuals Humphries. E.J. (::>000). Salillily risk assessnicru provide a relative basis for identifying JreJS were small for areas of low slope, but of the Central J Vest catchment (H<1('!"'lI'ic, at high risk of salinisation at regional scale. showed increasing variability with , Castlcreixh ,11"/ Bogall catchments}. A joint increasing slope. Potential discharge sites "~ initiative of the Central West Catchment Aownet Analysis Management Committee and the Departmcnr were identified using map algebra on A Flownet WJS constructed for the 735 of Land and Water Conservation. surface elevation, the HHS and krn ' Buckinbah Creek Catchment to Kazerni, C. A. (1999). Croundu.atcr jaaors ill [he topographic attribute conditions derived determine groundwater and salt flux. Key mal1agcmcl1[ 'f drylalld salinity ill the L'pper for saline sites. These sites compared Macquarie Valley, NSW, Australia. Ph.D. input included a smoothed and Jggregated favourably with mapped salt sites in the Project Report, Na tio nal Centre for HHS grid, the catchment boundary and southern part of the catchment, but less Groundwater mau.rgemcnc, University of recharge and transmissivity files. Input so elsewhere. Technology. SYdney (Unpublished). values for recharge (20 mm/yr; 3.3% MD13MC, 199'). (Murray-Darling Basin A fl o wn et constructed for the recharge rate using 604 mm.!yr rainfall) Ministerial Council). The Salinitv Audit: A Buckinbah Creek sub catchment using and transmissivity (2 m2 Id) were selected 100 year perspective, 1999. MDBC, Canberra. FAS has produced estimates for ground- using limited data from previous work. Nicholson, A.T. (1996). LOWliol[ of salitre sites ill water and salt flux. Simulations using relation 10 gC('f"XY and landionns . In; Semple, Flowne t simulations were conducted different recharge estimates show that any W.S (cd), Koen, TB., Williams, B.G., using five different recharge estimates to recharge above approximately 5 to 6 Murphy, B.W. and Nicholson, A.T (1996). examine the resulting changes in ground- mm/yr will contribute to groundwater Saline sft]lage scalds ill the Cmtm/lVesl ofNSIV water flux. The results demonstrate that rise because the system only has the Report 011 Sta,Re-2 l~fa cateoorisation L?fsaline sites any recharge above approximately 5 to 6 project. Technical Report No. 29, pp 60-67, capacity (assuming a maximum transmis- mm/yr will contribute to groundwater Department of Land and Water Conservation. sivity of2 m-'Id) to conduct 17,872 m' I d. rise because the system only has the PMSEIC \Ver. ::». 7 Jan, 1999. (Prime Minister's Using this groundwater flux and an capacity (assuming a maximum transmis- Science. Engineering, and Innovation sivity of 2 m.'/d) to conduct 17,872 average groundwater salinity of 1,772.4 Council). Drvland salinitv and its ill1paL1S0/1rural mg/l (2,532 !-lSI cm) the salt flux for the industries IIl1d [he landscape. Commonwealth rn3I d. The system reaches its maximum catchment was estimated at about 31.7 of Australia, ::>nd Meeting, Friday, -I capacity to carry water when the recharge tonnes/day. December 1998, 9am to 12.30pm. Cabinet rate is ~1 ':X, (assuming an average annual Room, Parliament House, Canberra. Follow-up work planned tor Phase-Il rainfall of about 604 mm). Salama. R.B .. Hatton. T. and Dawes, W. (1996). of this project will focus on hydro- Using a groundwater nux of 17,872 HARSD: Procedures and approaches 10 landscap« m3/d and an average groundwater salinity ecological and hydrological studies and classiiication, ~~r(llll/dlll£1tcr-levell/ll1ppillg, o1ldj7oll' of 1,772.4 mg/l (2,532 !-lSI cm) the salt remote sensing applications to investigate net mode/lil1g. Technical Memorandum 96: 27. December. 1996. Division of Water flux for the catchment is estimated at salinity in a high-risk subcarchmenr of Resources. CSIRO. about 31.7 tonnesl dav. This equates to Buckinbah Creek identified dunng the current stud,'. Salama. R.B .. Y c. L. and Broun. J. (1996a). an annual total of 11.5UO tonnes/yr (15.7 CtlllljJllrllfh'c ,'(lId)' (~r /I/Cf!I(lds t?( prc]Jl7Ti1lX tonnes/km.' per 1'1'). Salt input to the The Authors livdmul« lic.u! sll~"f:I((,s (111d tiu: introduction (?( Flownct catchment II-OJl1 an average 1ll/t{HlIlltnj h)'dr(l<~({)/o 40 WATER OCTOBER 2001 Volume 28 No 7 October 2001 Journal of the Australian Water Association Editorial Board F R Bishop, Chairman water 13 N Anderson, Fl Considine. W J Dulfer, G Finke, G Finlayson, G A Holder, B Labza, M Muntisov, P Nadebaum,J D Parker,J Rissman, CONTENTS F Roddick, G Ryan, S Grav 1':- Water is a refereed journal. This symbol 2 FROM THE FEDERALPRESIDENT: AWA Activities 'indicates that a paper has been refereed. Submissions 3 FROM THE EXECUTIVE DIRECTOR: A Legal Bent Submissions should be made to E A (Bob) Swinton, Technical Editor (see below for details). 4 INTERNATIONAL AFFILIATES: WEFTEC2001 Managing Editor 6 OVERSEAS REPORT: On the beach ... in London K O'Halioran Peter Stirling PO Box 84, Hampton Vic 3188 8 MY POINT OF VIEW: Tel (03) 95308900 Fax (03) 9530 8911 Where to Next on Water Quality Standards Dr Neil Byron Technical Editor E A (Bob) Swinton 12 CONFERENCEROUNDUP 4 Pleasant View Cres, Wheelers Hill Vic 3150 14 Thiess Services Riverprizes Tel/Fax (03) 9560 4752 WATER AWARDS: Email: [email protected] 16 CROSSCURRENT: Water News Around the Notion Crosscurrent Editor W (Bill) Rees PO Box 388, Artarmon, NSW 1570 FEATURES: Tel +61 29413 1288 Fax: (02) 9413 1047 GROUNDWATER AND SALINISATION Email: [email protected] AWA Head Office 27 MAPPING AND UNDERSTANDING SALINITY IN THE LANDSCAPE PO Box 388, Artarmon, NSW 1570 I Lambert, K Lawrie and C Pain Tel +61 29413 1288 Fax: (02) 94131047 Catchment management requires information from deep down in the regolith. Email: [email protected] 30 [iJ AIRBORNE GEOPHYSICS: BETTERINFORMATION FOR LAND MANAGEMENT Water Advertising & Production G Street Hallmark Editions Electromagnetic, Radiometric and Magnetic surveys mop sub-surface salt PO Box 84, Hampton, Vic 3188 Levell, 99 Bay Street, Brighton, Vic 3186 34 [Ii A FRACTURED ROCK AQUIFER: THE CLARE VALLEY PROJECT Tel (03) 9530 8900 Fax (03) 9530 8911 P Cook and A Love Email: [email protected] Graphic design: Mitzi Mann New methods give better estimates of groundwater behaviour -Water (ISSN 0310 • 0367) rI.I SALINITY-ASSESSMENT WITH HARSD: LITTLERIVER CATCHMENT, NSW is published eight times a year in the months of S W Davies, D Pollock, W A Milne-Home, R B Salama January, March, April, June, July, September, A regional-scale groundwater model estimates salt fluxes October and December. Australian Water 41 [I] AQUIFER STORAGE AND RECOVERY: REMOVAL OF CONTAMINANTS FROM STORED WATERS Association S Toze, P Dillon, P Pavelic, B Nicholson, M Gibert ABN 78 096 035 773 An international project investigates quality changes underground Federal President Barry Norman WATER AUSTRALIAN Executive Director WATER 45 [I] WATER AND WASTEWATER MINIMISATION: THE FISH ASSOCIATION Chris Davis PROCESSING INDUSTRY IN SOUTH AUSTRALIA Australian Water Associarion (AWA) assumes no B Dearman, N McClure and H Fallowfield responsibility for opinions or statements of facts Simple changes to factory systems payoff handsomely expressed by contributors or advertisers.Editorials do not necessarily represent official AWA policy. ENVIRONMENT Advertisements are included asan information service to readers and are reviewed before publication to 50 [II DESIGNING A MONITORING PROGRAM FOR ENVIRONMENTAL ensure relevance to the water environment and ~bjec- REGULATION: PART 1 . THE OPERATING CHARACTERISTIC CURVE tives of AW A. All material in Water is copyright and W Paul and N T Diamond should not be reproduced wholly or in part without Compliance or non-compliance? You could be 50% out! the written permission of the General Editor. 55 MEMBERSHIP Subscriptions Water is sent to all AWA members eight times a year. 56 MEETINGS It is also available via subscription. OUR COVER: The National Action Planfor Salinity and Water Quality was announced last year, to the tune of $700 Mfrom the Commonwealth, Salinity expresses itself at the suriace, but its causes lie deep underground, and the Bureau of Rural Sciences is directing a Salt Mapping Program. Groundwater investigations no longer rely solely on datafrom drill- holes: techniques developed for mineral exploration are now being applied. Photo by Wayne Lawler courtesy of AUSCAPE.