INTERNATIONAL SOCIETY FOR SOIL MECHANICS AND GEOTECHNICAL ENGINEERING

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This is an open-access database that archives thousands of papers published under the Auspices of the ISSMGE and maintained by the Innovation and Development Committee of ISSMGE. cOmmOn grOund 07 268 Common GroundProCeedinGs rock rock aquifers at nearsite a the power plant. presents summarypaperinvestigations the a of This the litt exploring received conducted previously aquifers as alternative water source for a 720 MW power plant at the Langat River. was have study Basin A Langat aquifer. the potential of rocks basement are Palaeozoic wetlands and basin, the in developments to risk declining regional groundwater levels. a poses subsidence emerging. Land are intrusion saline and overproduction including alluvial aquifers the the to from threats extraction B environmental groundwater increasing Langat of consequence the a As of development. aquifers alluvial productive Highly power plants) are shifting their water source from surface water to groundwater. Langat the in quality water industry, paper and surface pulp works, steel (e.g. deterioratingenterprises water-intensive of numbersincreasing Basin, and deficit water the with cope To 2003]. Sing salinity encroaching upstream with and in lows historic at levels — Basin Langat water the in with source drought 1998 the even became during water evident of shortage more A emerging. are deterioration and quality water pressures and shortages ecological water development, the with Concurrently economic development. p large-scale themuchrapid, focusof LumpurKuala urbanbeen other centres.has and It The Langat Basin (Figure 1) is the most urbanised river basin in , hosting the capital city of city capital the hosting Malaysia, in basin river urbanised most the is 1) (Figure Basin Langat The INTRODUCTION 1 resp nearby wetland and other groundwater stakeholders. with investigated been have fields well proposed the of aspects Environmental element finite three-dimensional a employing assessed were model. fields well proposed the for yields desi field well proposed various of performance expected The fractures and macro-pores provide the most effective flow path. the and by fracturescontributed is otherthe the by while macro-pores, contributed is which of one porosities: distinct two by characterized well be canmeta-sandstone the that investigationsshows core drill and data test borehole of Interpretation meta-san In weathered Lumpur Kuala identified as partially potentially fractured productive rock aquifers. at rocks and basement Palaeozoic jointed the forming fractured, a the exploration geophysical modelling, studies, hydrogeological groundwater detailed of results the on Based as a feasible alternative to alluvial aquifers. overprod or ar user lag end the to constraints, proximity and aquifers, Environmentalalluvial aquifers. alluvial shallow in wells yield high and cost low comparatively than attractive less typically are aquifers rock fractured in wells Deep ABSTRACT Keywords: Langat Basin, dual grporosity, FEMWATER, International Airport / Malaysia – challenges and c and – challenges Malaysia / Airport International Groundwater exploration adjacent to the Kuala Lumpur KualaLumpur tothe adjacent exploration Groundwater hydrogeology ANdgrouNdwAter 10thAustrAliAnewZeAlAndConferenCeonGeomeChAniCs Coffey Geotechnics Pty Nathan, Ltd, QLD, Australia exploring a fractured rock aquifer aquifer rock fractured a exploring Detlef BringemeierDetlef e good reasons to explore fractured rock aquifers rock fractured explore to reasons good e used to assessused the sustainableof fracturedyield inter-granular pores. This study shows that the that shows study This pores. inter-granular oundwater modelling, Kenny Hill Formation sn r te an agt o groundwater for target main the are asin oeta o fatrd aaooc rock Palaeozoic fractured of potential entoa Arot KI) ae been have (KLIA) Airport ternational gns was investigated, and sustainable and investigated, was gns h Lna Rvr te an water main the — River Langat the cnmcl osrit including constraints economical BrisBAne

hances of of hances e teto a a as attention le hetnd by threatened ect to KLIA, a KLIA, to ect [Shaaban and [Shaaban d numerical nd soe beds dstone hysical hysical and cin of uction aquifers, tairpy olwn i tkn rm icsin icue i Gbe ad ucio [93 and [1973] Hutchison and Gobbet and in lithology included of summary discussions The from Basin. taken Langat the is of following map stratigraphy geological general the shows 1 Figure and mountainous terrain km ofand 945 coastasquare about comprising km, square 2,100 about of area an has Basin Langat The GEOLOGIC SETTINGS 2 eoie i fuil n salw aie niomns Cas t vr-ore ad gae of ty gravel is aquifer sandy The Basin. very-coarse Langat the of to aquifer main were Coarse and the gravel,considered is environments.strata Quaternary the of to base the at marine Pliocene) to clay (Palaeocene Formation Simpang shallow from and downward fluvial grade sediments in these deposited general, In 1973]. Hutchison youn progressively grow and bedrock, eroded overlay unconformably Formations Beruas and Gula Kempadang, Simpang, the of clay and silt sand, gravel, theOn coastalplain, Quaternarydeposits consistin deformed less than rockscomparatively of the Howthornden Formation. are strata These Formation. slates, Hill quartzite, Kenny of meta-sandstone, schist quartz Permo-Carboniferous and phyllites is foothills the in rock predominant The and deformed highly are Pre- rocks and Formation have undergone two phases of deformation [Gobbet an rocks Howthornden Formation. igneous Howthornden Permian the of includes phyllite area mountainous the in Bedrock JMG/JICA [2002]. Palaeozoic bedrock in the northeastern part of the coastal plain is exposed at several hillocks several at exposed is plain coastal the of part northeastern the in bedrock Palaeozoic and varies from about 50 100m to morem than further toward the coast [JMG are completely dissected. rockBrecciated or mylonite is frequently observed in t volumes rock larger frequently and faults, the to faults. adjacent increases density striking joint and fracture west-northwest The numerous by fractured intensely are and west-northwest, degrees phyllite are and rocks The slates weathering. minor of degrees various with with Kenny meta-sandstones the comprise to typically correspond and to 1999] thought generally [STRATA are Formation hillock Tadom Bukit the at outcrops Rock Bukit (engl. Hill) Tadom to themost power proximal iue1 General geology and selected environmental receptors of the Langat Basin. Figure 1: SUMATRA THAILAND MALAYSIA PENINSULAR K U A L A L U M P U R LANGAT BASIN SINGAPORE

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a t N Bukit Tadom h Putra Jaya Lumpur Kuala KLIA 4 10thAustrAliAnewZeAlAndConferenCeonGeomeChAniCs g ofPalaeocene g Holocene through unconsolidated plant (Figure 1). upturned and generally dip between 45 and 85 and 45 between dip generally and upturned pically several metres thick near the foothills, the near thick metres several pically l plain. ger and thicker toward the coast [Gobbet and [Gobbet coast the toward thicker and ger Sg d Hutchison 1973]. . La ng at hydrogeology ANdgrouNdwAter 5 0 4 h LEGEND 1,155 square km of hilly of km square 1,155 Mega Steel Mega / Armsteel Major Impoundment (Meta-Sandstone,Schist) Formation Kenny Hill Formation/ SchistJelebu HawthorndenSchist/ Granite Paya WetlandIndah Main River BeruasFormation Gula Formation Gula International Airport Kuala Lumpur Power Plant ҟ/JICA 2002]. 10 eoin cit and schist Devonian hese fault zones. 15 20 km 20 15 BrisBAne Hill with 269

cOmmOn grOund 07 cOmmOn grOund 07 270 Common GroundProCeedinGs al 1 Pretg o mt-adtn i oe scin f lgtse brhls n computed and boreholes slug-tested of section open hydraulic conductivity for each open section. in meta-sandstone of Percentage 1: Table Hill Formation. ie i Tbe ws band Te tog orlto idcts mjr otiuin f the of contribution major a indicates correlation strong of Therocks the of conductivity hydraulic obtained. the to beds meta-sandstone jointed was and fractured 1 Table in given deep test well (TW 1) was developed. Monitoring bo Monitoring developed. was 1) (TW well test deep m 210 diameter, mm 250 a and period, year 2 a over conducted program investigation geophysical ba identified was Tadom Bukit at location well test A 15] Te curne f easnsoe n ah pn eto ad h hdalc conductivity hydraulic the and Hvorslev section to open according t each for analysed 0.89 coefficient correlation A correlated. was section open each for computed in and meta-sandstone out of carried occurrence was The boreholes [1951]. cased partially 7 of testing Slug . Investigation program 3.1 BEDROCK HYDRAULICS AT BUKIT TADOM hilloc the 3 to close thick metres several is alluvium The becomes thicker with increasing distance from the hillock. surface. the at developed peat with clay sandy and silty soft, of composed mainly deposits alluvial by enclosed is Tadom Bukit The re meta-s light a altered colored sand.to disintegrated completely The is parts in and discontinuity. strength low the of and of porous highly side one along developed preferentially is zone alteration the and fractures, persistent and faults along altered deeply is meta-sandstone The (Figure 2) and each boreholemonitoring slug-tested.was . Bedrock permeability 3.2 pumping test for and a period of 24 hours following adj bores monitoring in and well test the in levels ho 48 for pumped 12 was for L/s It 12 hours, 24 2001. for L/s 6 July i.e. rates; varying in undertaken was 1 TW Location of pumpingand monitoring test well TW1 bores at Bukit Tadom, Malaysia. of test pumping structured A Figure 2: hydrogeology ANdgrouNdwAter 80 85 80 85 -8200 -8250 -8300 -8350 -8400 oe ecnaeSnsoe Hydraulic. Conductivity Percentage Sandstone Bore M 10 4.13E-06 1.15E-06 2.29E-08 6.43E-07 2.15E-06 3.54E-06 100 75 50 79 72 DM7 92 DM7 DM6 DM5 DM2 DM1 DM7 m 200 10thAustrAliAnewZeAlAndConferenCeonGeomeChAniCs ED9 M SM1 SM6 SM3 DM5 DM5 SM2 TW1 SM4 SM5 DM1 DM3 DM2 Easting DM6 DM6 acent to the test well were recorded during the during recorded were well test the to acent the cessation of pumping [Bringemeier 2001]. hours and then 6 L/s for 12 hours. Groundwater hours. 12 for L/s 6 then and hours reholes were established around the test well test the around established were reholes sed on the results of a staged geological and and geological staged a of results the on sed DM4 SM7 [m/s] BrisBAne -40200 -40150 -40100 -40050 -40000 -39950 -39900

Northing he two data sets data two he nsoe is andstone d to cream to d the Kenny the r, at urs, and k A stationary three-dimensional FEMWATER groundwater model was developed and calibrated with stationary pressure heads recorded during the stages advanced of pumping 6 at L/s and 12 calibrated and developed was model groundwater FEMWATER three-dimensional stationary A NUMERICAL MODELLING 4 and 12 L/s (b) pumping test and recovery test (c). a and early employing storativity Computed 4: Figure were pores inter-granular the for as well as macro-pores and fractures determined. The results are shown in Figure 3 and Figure 4. the non- for Theis The storativity pores. transmi the of inter-granularestimates and sub-set, data the each to applied of was method test properties equilibrium hydraulic the by dominated increasingly later the whereasmacro-pores, and fractures the of propertieshydraulic the by dominated be to assumed is recovery and drawdown the of stage early The each. sets data into two divided were test pumping the of stages recovery and drawdown different the of records The determined were [Todd 1980]. parameters hydraulic Aquifer site. at undertaken the tests pumping from determined was area Tadom Bukit the of hydraulic aquifer The and 12 L/s (b) pumping test and recovery test (c). Figure 3: Computed transmissivity and advanced employing early stage pumping records for 6 L/s (a)

Transmissivity [m2/s] 1.E+00 1.E-05 1.E-04 1.E-03 1.E-02 1.E-01 Storativity [-] 1.E+00 1.E+01 1.E-06 1.E-05 1.E-04 1.E-03 1.E-02 1.E-01 Common GroundProCeedinGs ED9a EARLY STAGE PUMPINGEARLY STAGE ED ED 9 a 9b EARLY STAGE PUMPINGEARLYSTAGE ED ED9c 9 b DM5a ED9c DM DM5 5b DM5c a DM5 DM6a b D M DM 5 c 6 DM DM6cb 10thAustrAliAnewZeAlAndConferenCeonGeomeChAniCs 6 a DM DM1a Vertical lines represent 95% confidence interval. Vertical lines represent 95% confidence interval. 6

b ADVANCEDPUMPING STAGE DM1b DM6c ADVANCED PUMPING STAGE

dvanced stage pumping records for 6 L/s (a) (a) L/s 6 for records pumping stage dvanced DM DM1 1c DM2a a hydrogeology ANdgrouNdwAter DM1 DM2b sn te nltcl ehd o Theis of methods analytical the using b DM DM 1 c 2 c DM DM4a 2 a DM4b DM2b DM4c DM2

c TW DM4 1- TW1-6l/ a s be to assumed is stage D M TW1-112 4 b l/s DM TW 2 l/s-re 4 1 c -6l/ c s rec ssivity and ssivity L/s. BrisBAne 271

cOmmOn grOund 07 cOmmOn grOund 07 272 Common GroundProCeedinGs Four groundwater extraction scenarios were simulatedwere scenarios extractiongroundwater Four the hydraulic conductivity of the schist layers. by dominated is planes bedding the to perpendicular conductivity hydraulic the whereas sandstone, lcd ln te eiee o te rpsd el il. n cnro I te ubr of number the II, Scenario In field. well proposed the of perimeter the along placed were L/s 6 of rate withdrawal a with points well spaced equally 5 I, Scenario In areas. adjacent and TadomBukit at regimesgroundwater the on configurationsfield well different and rates withdrawal m the of conductivity hydraulic the by dominated is interbedding the of planes bedding different assumed was the c It layer. into and Hill Kenny taken the schist to been anisotropy and have rocks meta-sandstone these of of interbedding conductivity hydraulic The negligible. is pores granular c hydraulic the macro-pores,fracturesand the conductivityofhydraulic the in field hydrogeological the lay of results interpreted two as modelled were assig parameters deposits hydraulic alluvial The the thickness. and variable Formation Hill Kenny the of rocks The Pressure head changes in the Kenny Hill layer of 0 0 of layer drawdown which therefore can be considered as a max Hill the from leakage Kenny Taking negligible layer. Hill Kenny and the into aquifer alluvial rates the withdrawal L/s 60 in assuming location, MegaSteel/Armsteel changes head the Pressure at drawdown maximum m 5 with Airport International Lumpur airports northwest boundaryfor 120 computed L/s pu Kuala the of boundary the de of cone the L/s 60 than more of rates withdrawal fluct level groundwater natural expected within is this and L/s 60 of rates withdrawal at Airport International Lumpur Kuala the of area the for computed was m 0.3 than less of Drawdown and permeability of couldaquicludes underlay that metres thickness the on several depending less be may to and estimates conservative up are these Nevertheless, and60 L/s. less, or L/s predicted 60 is of Indah rates Paya withdrawal at table groundwater the long-term, the Over northeast to south-southwest. ellipti an located at its centre (Figurethe computed 5). coneThe main axis of todepression of is oriented north- limited be to found was depression of cone computed The Figure 5: Computed drawdown in metres at Bukit Tadom wellfield with 10 bores of 6L/s each. from 6 L/s to 1 2L/s at each well. and I scenarios to similar are IV and III Scenario 5). (Figure well each for L/s 6 at kept was withdrawal of rate the whereas 10, to 5 from increased hydrogeology ANdgrouNdwAter 10thAustrAliAnewZeAlAndConferenCeonGeomeChAniCs Power Plant Power Proposed

0 2 4 6 km 6 4 2 0 S S

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-0.5m t t -1m Indah Paya -2m -10m -5m leakage into account would reduce the computed the reduce would account into leakage vestigations. It was assumed that, compared with compared that, assumed was It vestigations. II except that the withdrawal rate was increased was rate withdrawal the that except II the wetlands. ned to the Kenny Hill layer were based on the on based were layer Hill Kenny the to ned that the hydraulic conductivity parallel to the to parallel conductivity hydraulic the that mping rates. pression is predicted to extend further across further extend to predicted is pression InternationalAirport LumpurKuala to study the effects of different groundwaterdifferent of effects the study to imum drawdown at the specified rate. Kampong Bukit Tadom Power Plant LangatKuala o m ee optd o the for computed were m 2 to nieain y sinn hydraulic assigning by onsideration o wtdaa rts f oe than more of rates withdrawal for BrisBAne cal area with Bukit Tadom Bukit with area cal o al es hn m for m 1 than less fall to onductivity of the inter- the onductivityof

el was wells uations. At uations. r of ers eta-

Army Corps of Engineers, Experiment Waterways Station, Bulletin 36, Vicksburg, 50 p vrlv MJ (1951). M.J. Hvorslev, Singapore (1973). C.S. Hutchison, and D.J., Gobbett, Darul District, Langat Kuala Belas, Ehsan Dua Tanjung of Tadom, Bukit at withdrawal (2001). D. Bringemeier, REFERENCES Utama, Perunding and comments constructive his for Everard Malaysia for theto use projectpermission data. Keith thank to wishes author The ACKNOWLEDGEMENTS this respect. unce reduce would aquifers alluvial the in located bores groundwaterfrom data additional production and with head model the Recalibrating interception. field well of area the limiting aquif alluvial the MegaSteel/Armsteel well field is located at the fri However, possible. not are field alluvial the tapping field well any of productivity on sparse data. Therefore, conclusive statements the effect on of a well field at Bukit Tadom on the b exchange groundwater of understandingcurrent The water wetland the between the exchange affect water significantly underlying bedrocks are required the to verify the mode would on investigations rate further extraction However, L/s 60 balance. with Tadom Bukit well a at that unlikely considered field was it wetland Indah Paya the underlying bedrock the in m less 1 of than head pressure in decrease predicted a With fluctuations. groundwater natural within be to were KLIA the at heads groundwater of drawdown rate this At Tadom. Bukit at field awell for suggested was L/s 60 of yield sustainable estimated an results modelling numerical on Based rock constrains the sustainable a well field yield at of Bukit Tadom. t aquifers alluvial the of stakeholders International and AirportLumpur Kuala the wetland, Indah Paya sensitive environmental the to proximity The hillock the and proximity to the power plant makes Bukit Tadom a preferred location for a well field. at aquifer rock the to depth Shallow groundwater. of amounts considerable yielding of capable aquifer an be to considered formationare Hill Kenny the ofmeta-sandstones fractured and With a transmissivityaWith the order in 450of m CONCLUSION 5 Todd, D.K. (1980). unpublished Pow Sanyen Genting for prepared BT-05, Report Appraisal Study, Feasibility & Resources JMG TAA 19) (1999). STRATA 2003, Kuala Lumpur strategies management and policies related (2003). L.K. Sing, and A.J., Shaaban, Cooperation Agency (JICA) and Geoscience Department Malaysia Malaysia. in Basin Langat the for management  IA 20) (2002). JICA , prepared for Perunding Utama Sdn Bhd, unpublished . Regional Geology Series, Wiley, New York et al., 438 p rudae epoain rjc – hs 2 t Tdm Site. Tadom Bt. 2 Phase – project exploration Groundwater Groundwater Hydrology h suy n h ssanbe rudae rsucs a resources groundwater sustainable the on study The Common GroundProCeedinGs ie a ad ol emaiiy n rudwtr obse ground-water in permeability soil and lag Time Evaluation of the effects on the groundwater regimes due to groundwater to due regimes groundwater the on effects the of Evaluation Droughts in Malaysia: A look at its characteristics its at look A Malaysia: in Droughts 2 . Wiley, New York et al., 535 p /day and a storativity in the orderandthe /daya storativity4 of in elg o te aa Pnnua Ws Mlyi and Malaysia West – Peninsula Malay the of Geology Wtr n Dang 20 Cneec, 82 April 28-29 Conference, 2003 Drainage and Water . 10thAustrAliAnewZeAlAndConferenCeonGeomeChAniCs Volume 1, Executive Summary, Japan International Japan Summary, Executive 1, Volume nge of Bukit Tadom well field’s cone nge of depression hat may be hydraulically linked to the underlying the to linked hydraulically be may hat aquifers, e.g. the MegaSteel and Armsteel well well Armsteel and MegaSteel the e.g. aquifers, lling results. r pnh u twrs ui Tdm n the and Tadom Bukit towards out pinch ers etween alluvial aquifers and bedrock is based is bedrock and aquifers alluvial etween hydrogeology ANdgrouNdwAter

rvations u d environmental nd eln ad the and wetland 10 Groundwater -3 thealterated Ms. U.S. Miss., . er Sdn Bhd, Sdn er rtainties in rtainties predicted , impacts, , BrisBAne 273

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