Journal of Science and Technology Original Article Kathmandu, Nepal Central DepartmentofGeology,GeodisasterResearchCenter,TribhuvanUniversity water availability inthearea. in the Bhabar zone and find out the alternatives to ensure the The studywasaimedtoexplore thegroundwatercondition district thatcoverstheSiwalik RegionaswellTeraiRegion. in parts of the Chulachuli VDC (ward nos. 6 and 7) of Ilam This paperdescribesthehydrogeological studycarriedout irrigation waterdemand. Siwalik Regioninthenorthsoastomeetdrinkingand groundwater resourcesintheBhabarzonesouthand this regard, it is extremely necessary to explore and exploit the foothillareashasbeenincreasinginrecenttime. In management in the area. Furthermore, the population along the of only onrain-fedirrigationbecauseoflackproperwater areas significant and limited agriculturallandavailableintheareahastodepend drinking for the from scarcity suffer to water have areas these at residing people the zone. Thoughseveralrivers are drainingthrough the areas, groundwater explorationandexploitationintheBhabar A fewstudieshavebeencarriedouttoassessthestatusof Nepal. along thesouthernfoothillofSiwalik(Churia)Rangein for drinking andirrigation purpose is always a challenge available intheregion.Onotherhand,availabilityofwater and sustainablesourceofwatersupplyasitisabundantly groundwater intheTeraiRegionisconsideredasareliable resources havenotbeenfullyassessed(FAO2011).The water in the TeraiRegion of Nepal. However, groundwater role toensurethesupplyofdrinkingwaterandirrigation the availabilityandexploitationofgroundwaterplaysavital Bangladesh andNepal(VillholthSharma2006).Hence, as theonlysourceforirrigationinIndia,China,Pakistan, fact the that approximately one billion people rely on groundwater from reflected is groundwater of importance The 1. Introduction Dinesh Pathak Ranjan Dahal A Accepted 18October2016 Revised 11September2016 Received 1March2016 A E-mail: [email protected] Tel: 977-9841476041 # image groundwater table;hydrogeology;satellite Bhabar zone;groundwaterrecharge; K Siwalik Foothill ofeastNepal Water Availability andHydrogeological Condition inthe © 2016byNepalAcademyofScienceandTechnology Nepal JournalofScienceandTechnology(NepalJSciTech)(2016),17(1):31-38 C c rticle eywords orrespondence ademic H E istory ditor #

while theMiddleTeraiisrepresentedbybettergroundwaterpotentiality. characterized bythelowavailabilityofwaterfordrinkingandirrigationpurposes information andupdatethegeologicalmapofarea.TheBhabarzoneis field the in and interpretationofsatelliteimagerieshadbeencarriedouttoextractrelevant collected data primary and information secondary The condition. Development Committee of Ilamdistrict,Nepaltoassessthehydrogeological A detailedinvestigationofhasbeencarriedoutinpartsChulachuliVillage recharge, butthereisarestrictedwateravailabilityduetodeepertable. Because ofporousgeology,theBhabarzoneispotentialareaforgroundwater the northern part (Bhabar zone) that becomes finer (up to gravel size) southwards. Indo-Gangetic Plainconsistsofcoarsesand,gravel,pebble,cobbleandbouldersin mainly the alternating beds of sandstone and mudstone and conglomerate. The Gangetic Plaininthesouth.TheSiwalikRangeiscomposedofsedimentaryrock, The SiwalikfoothillisboundedbetweentheRangeinnorthandIndo- A bstract

trict. (inset:locationofIlamdistrict inNepal) Fig. 1.Locationofthestudyarea inChulachuliVDCofIlamdis in the south (DMG 1984). The Siwalik Zone (Sub-Himalaya) units, i.e.Siwalik ZoneinthenorthandIndo-Gangetic Plain geological different two of mainly comprises area study The 1.2 of 11.5km of theChulachuliVDCIlamdistrictandoccupiesanarea study areaislocatedinthePeltimariWardnumbers6and7 traversing throughthesouthernpartofTeraiPlain.The Plain) inthesouthernpart.TheEast-WestHighwayis in thenorthern part and the plainareas (Indo-Gangetic mountainous regions (ChuriaHillsandMahabharat Range) Region (Fig1seeinset).Thedistrictisoccupiedbothbythe Ilam DistrictissituatedintheEasternDevelopmental 1.1 The StudyArea The Geology oftheStudyArea 2 (Fig.1). -

31 Geology NJST Pathak

consists of sedimentary rock namely mudstone, sandstone toboulders and extends southwards from the foothill area. and conglomerate. However, in the study area, only the Subsurface Terrace deposits made up of uncemented or only alternating beds of sandstone and mudstones belonging weakly cemented clay sands and gravels and having thickness to the Middle Siwaliks are distributed. Schematic sectional of approximately 270 m has been reported from Parwanipur view showing the Siwalik and Indo-Gangetic Plain shows the area (Itihara et al. 1972). These are considered to be a wedge- position of Bhabar Zone (Fig. 2). shaped sedimentary pile which is pinched northwards to the foothills and thickens southwards to the plain (Shibasaki and Miyamoto 1971). This zone is comprised of both the alluvial materials as well as some colluvial materials derived respectively from the river debouching from the Siwalik Hills and mass movement from nearby hills. During the pre- monsoon season, the rivers become dry while entering this zone because of high infiltration rate. Such evidence was observed during the field study. Satellite imageries have been extensively used for groundwater exploration in hard rock as well as in identification of suitable area for groundwater recharge (Bruning et al. 2009; Yeh et al. 2009; Krishnamurthy et al. Fig. 2. Schematic section from north to south showing Siwalik hill 1996). The satellite image of the study area shows northern and Indo-Gangetic Plain (Bhabar Zone, Middle and Sothern part of the study area is covered by the vegetation (red color Terai) in Fig. 4). Likewise, the mountainous terrain representing the Siwalik Region has been clearly indicated on the image. Detailed geological map of the area has been prepared from The density of vegetation is less in the southern part as the data collected during the field study (Fig. 3). The geology random red patches are seen on the image. The rivers are of the area can be broadly subdivided into Siwalik Zone and sharply bent along the foothill which helped to accurately Indo-Gangetic Plain (Bhabar Zone and Middle Terai) from trace the fault separating the Siwalik Region in north from north to south. the Indo-Gangetic Plain in the south. In addition, the rivers The Middle Siwalik rocks characterized by thick beds of are braided once they debouch from the mountainous part salt and pepper colored sandstone intercalated with thick that is the reflection of the presence of coarser material, the beds of mudstone are exposed at the upper reaches of the Bhabar Zone in the area. The river becomes narrower in the Bidhuwa Khola and further north. The dip direction of the southern part of the study wards belonging to the Middle rocks varies from south to northwest. Terai.

2. Materials and Methods

The study consisted of the collection and study of secondary data, mainly existing reports, geological and topographical maps. The field survey basically focused to collection of geological and hydrogeological data. The geologic and structural control on groundwater distribution has been analyzed. Hydrogeological database of the study area has been prepared in GIS and potential zones for groundwater exploitation have been delineated. The data sets utilized in the study were topographical map (scale 1:25,000) of the Department of Survey, Government of Nepal, geological map published by Department of Mines and Geology, Government of Nepal, satellite image (10 m spatial resolution, multispectral) and data collected in the field. Multispectral satellite image covering the study area (10 m spatial resolution) has been used to explore the recharge zone, distribution of settlement, potential areas of groundwater occurrence etc. Likewise, the study area (Ward number 6 and 7 of Chulachuli VDC) has been outlined on the satellite image Fig. 3. Geological map of the study area (Fig. 4). Different hydrogeological setups were demarcated in the The Siwalik and Bhabar zones are demarcated by a thrust study area with the help of terrain characteristics and river fault named as Himalayan Frontal Thrust (HFT). A sharp morphology that is clearly observed on the satellite image change in the river course can be observed while the river that guides the areas to be focused from different `aspects crosses the SE-NW extending thrust. The presence of fault during the field study. has great hydrogeological significance as it enhances the The information useful for the identification of groundwater occurrence in the area (Pathak 2011). groundwater occurrence in the area like drainage, land use/ The Bhabar Zone is characterized by the thick succession land cover was extracted from the Topo-sheet (scale 1:25,000) of unconsolidated sediments ranging in size from clay

32 Nepal Journal of Science and Technology , 17(1), 2016, pp. 31-38 Nepal Journal of Science and Technology Original Article study area. topographic map.Therelevantlayerswereextractedforthe ward no.andtransportationwerealsoderivedfromthe In addition, other relevant information like settlement, VDC, produced bytheDepartmentofSurvey,GovernmentNepal. aries Fig. 4.Satelliteimageofthestudyareashowinggeologicalbound collected usingasystematicchecklist. was data hydrogeological The information. different obtain is shown in Fig. 5. Total of 17 people were consulted to points observation of distribution The locations. different information ofthestudyarea,observationsweremadeat33 wells inthearea.Inordertocollect relevant hydro-geological parameters arenotavailableastherenoinvestigation condition ofthearea.Thelitho-logsaswellaquifer detailed informationongeologyandhydrogeological Fig. 5.Observation pointsinthestudyarea F ield investigationwascarriedoutforcollectingthe - are two major rivers flowing southward originated from the from originated southward flowing rivers major two are as theoccurrenceanddistributionofgroundwater.There in thedevelopmentofparticulartyperiversystemaswell role significant plays It area. the of condition terrain the by around 180mamsl.Geomorphologyofaregionisindicated 56% and10%,respectivelyinthestudyarea. areal The coverage bySiwaliks,BhabarZoneandMiddleTeraiare34%, locations. different at withthe logs lithological verified reported was observation field The Zone. Bhabar Several streamsoriginatefromthesouthernmarginof observed duetothechangeinsedimentsizeandelevation. Terai inthesouthwasdemarcatedbasedonseepages rise tothepresenceofsprings.TheBhabarZoneandMiddle sandstones infracturedconditionformsgoodaquifergiving to coarsegrainedsandstoneandmudstonebeds.The Middle Siwalikisrepresentedbyalternatingbedsofmedium 3.1 Geology andGeomorphology 3. ResultsandDiscussion have beenpreparedinGIS. been preparedfromthecollecteddataandrelevantmaps has database digital Likewise, . field the in map base as used observation pointandthetopographicalmap(1:25,000)was System (GPS)wasusedtoobtainthecoordinatesof (piedmont) ZoneaswellMiddleTerai.GlobalPositioning north belongingtoSiwalikRange(MiddleSiwalik),Bhabar fall around the boundary between the Piedmont zone and Terai (observation point15)whilethepoints 2,17,19and21 Southward fromthePiedmont zone,thereliestheMiddle rivers emergingfromthemountainous parttothePlainarea. the Plainarearesulteddueto coalescingfanformedbythe are alittlebitelevatedportion inthenorthernmostpartof 27, 29,30,32and33fallswithin thisgeomorphiczone.These Nepalese context.Theobservationpoints1,3-7,16,18,20, 22- by thepiedmontzone,alsoknownasBhabarZonein the South of the foothill region, the area is mostly represented zone. Thesearemostlyrepresentedbythefoothillareas. 17, 19,21,28and31lieinthecontactofSiwalikPiedmont ranges fromnarrowtowiderones.Theobservation points 8, with denudatedmountainousparttotherivervalleys,which represented bytheSiwalikRange.Itvariesfromrockyarea briefly summarizedbelowinTable1. geomorphologic conditionoftheobservationpoints are gradually southwardslopingTeraiPlain(MiddleTerai).The parts. Theseareabitelevatedportionandfollowedby is formedwhentheriverdebouchfrommountainous topography. The piedmontzonerepresentthefandepositofriverthat gentle to flat with region mountainous the of terraces aremarginallydistributedatthesouthernmostpart variable has width dependinguponthestructureandlithology.The Range Siwalik the through flowing rivers the riverbed northern partoftheareawithrockoutcrops.Likewise, plain), flood and and plainareas.Hillhillslopescanbeobservedinthe (fan zone piedmont terraces, area can be subdivided into hill and hill slopes, river valley, above meansealevel(amsl).Geomorphologically, the study rivers originatingfromtherecentdepositsinsouth. study area.Besidesthesetworivers,thereareothersmall the of east through flowing is one other the while boundary Siwalik Range. Bidhuwa River is flowing through the western The recentdeposits are distributedupto the elevationof The observationcoveredthemountainouspartsin The observationpoints9to13lieinthemountainousarea The elevationofthestudyareavariesfrom140mto520

33 Geology NJST Pathak

Middle Terai. In addition, sustainable groundwater management must Thee geomorphic zones have their own significance from take into consideration of the pollution sources and the po- the groundwater occurrence point of view. For example, the tential of fluid percolation which could convey pollutants to rocky area can possess fractured aquifer while the wide river the aquifer (Collina and Melloulb 2001). valleys within the mountainous part can have groundwater The southern part of the study area is mostly occupied by at the unconsolidated sandy/gravelly aquifer. Likewise, cultivated land comprising 66% of the study area while the the piedmont zones can have the recharge zone with poor northern part belongs to the Siwalik Hills that are occupied shallow aquifer system because of the presence of coarser by forest area accounting 28% of the study area (Fig. 6). The materials while the Middle Terai can have good groundwater area occupied by orchard is around 1% of the study area that occurrence even at shallow depth due to occurrence of mostly lies in the western part of the study area. relatively finer aquifer (sandy/gravelly) material.

Table 1: Geomorphologic description of the study area with reference to observation points S. N. Observation Geomorphology/Landform Point 1 1 Piedmont (Bhabar) Zone 2 2 Lower margin of Piedmont (Bhabar) Zone 3 3-7 Piedmont (Bhabar) Zone 4 8 Contact of Piedmont (Bhabar) zone and Siwaliks 5 9 Middle Siwaliks, rocky area 6 10-11 Middle Siwaliks, wide valley 7 12-13 Middle Siwaliks, narrow valley 8 14 Piedmont (Bhabar) Zone /river terrace 9 15 Middle Terai 10 16 Piedmont (Bhabar) Zone 11 17 Lower margin of Piedmont (Bhabar) Zone Fig. 6. Land cover in the study area 12 18 Piedmont (Bhabar) Zone The present land use shows that the area is still in good con- 13 19 Lower margin of Piedmont (Bhabar) dition for groundwater recharge as significant percentage Zone of the study area is still under vegetation cover. The area is represented by fair distribution of settlement, which has not 14 20 Piedmont (Bhabar) Zone yet converted into built up area. Therefore, it can be assumed 15 21 Lower margin of Piedmont (Bhabar) that the groundwater recharge as well as quality is still in Zone good condition. 16 22-27 Piedmont (Bhabar) Zone 3.3 Source and Availability of Water 17 28 Contact of Piedmont (Bhabar) Zone The residents of the study area have been utilizing the sur- and Siwaliks face water and groundwater for drinking purpose. The sur- 18 29-30 Piedmont (Bhabar) zone face water has been tapped from the northern part of the 19 31 Contact of Piedmont (Bhabar) Zone study area from springs in the Siwalik Range. Likewise, the and Siwaliks dug wells have been used for drinking purpose both in the northern part (around the foothill) and southwards at lower 20 32-33 Piedmont (Bhabar) Zone part of the Bhabar Zone. Similarly, hand pumps have been 3.2 Land Use/ Land Cover installed to exploit groundwater from the middle and south eastern part of the study area, basically falling in the southern Land cover of the area is one of the important factors con- part of the Bhabar zone and Middle Terai. Attempt of utiliz- trolling the occurrence and quality of groundwater, it espe- ing surface water for irrigation is not possible for round the cially has pronounced effect on the groundwater recharge. year due to low water availability at the pre-monsoon period. Land use affects groundwater resources through changes in Groundwater has been mostly utilized for the drinking recharge and by changing demands for water. Inappropriate purpose through dug wells and hand pumps while the spring land use, particularly poor land management, causes chronic water from the Siwalik Region have been used for the water groundwater quality problems (Lerner and Harris 2009). supply in the southern part (Fig. 7; Table 2). Groundwater is Analysis has shown that conversion of woodland to high-den- the main source of drinking water in the area that is utilized sity residential and commercial uses causes an eleven- to round the year in majority of places with the exception of ob- nineteen-fold increase in runoff volumes, and loss of 11 to 100 servation points 4, 18, 20, 23, 24 and 31, where it is available percent of the natural groundwater recharge (Harbor 1994). for about 9 months in a year. Even the tap water supplied

34 Nepal Journal of Science and Technology , 17(1), 2016, pp. 31-38 Nepal Journal of Science and Technology Original Article 22 33 21 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 S. N. 21 20 19 18 17 16 15 14 13 11 10 9 8 7 6 5 4 3 2 1 S. N. Table 2:Availabilityofwaterandexploitationgroundwaterinthestudyarea ity. Likewise,very lowpercentageofhouseholds inthesouth and TaloShanti Chowkarehavinggooddrinking waterfacil tral partofthestudyarea.All thehouseholdsinBidhuwaDill mostly lyingaroundtheAitabare Peltimarivillageinthecen Jimali Tolehavegooddrinking waterfacility.Theseareasare lacking of drinking water facility while only 4% households of chowk andAitabarevillage(obs pt.2,7,29,31,32,33)aretotally ruke Tole,Padamchowk,Janta Tole,KhalbaleYalamber The abovedatashowthattotalof379householdsfromTum Table 3:Availabilityofdrinkingwaterfacilityinthestudyarea part ofthearea. to transportwaterthroughouttheyearfromsouthern of thestudyareaishavingseverescarcitywaterthatneed timari (obs.Pts.32and33)lyinginthewesterncentralpart 29) to9months(atobs.Pt7).TheareaaroundAitabarePel through thespringisavailableonlyfor6months(atobs.Pt. 33 32 31 30 29 27 25 24 23 22 20 18 17 7 6 5 4 3 2 1 Point Obs. 32 31 30 29 27 25 24 23 22 20 18 17 7 6 5 4 3 2 1 Obs. Point Aitabare-7 Yalamber Chowk-6 Khalbale Tole-6 Jimali Tole-6 Janta Tole-6 Laxmi Chowk-6 Kirateshowr Sec.School-6 Bagaiche Tole-6 Tidio Tole-6 Chulachuli VDC,W.No.7 Satpatre-7 Unsathi PariwarTole-7 Talo Santichowk-7 Padam chowk-7 Jogi Tole-7 Bidhuwa dill-7 Tumruk Tole-7 Tumruk Tole-7 Tumruk Tole-7 Santi Chowk-7 Village-Ward Number Aitabare-7 Yalamber Chowk-6 Khalbale Tole-6 Jimali Tole-6 Janta Tole-6 Laxmi Chowk-6 Kirateshowr Sec.School-6 Bagaiche Tole-6 Tidio Tole-6 Chulachuli VDC,W.No.7 Satpatre-7 Unsathi PariwarTole-7 Talo Santichowk-7 Padam chowk-7 Jogi Tole-7 Bidhuwa dill-7 Tumruk Tole-7 Tumruk Tole-7 Tumruk Tole-7 Santi Chowk-7 Village-ward No. None (transportfromsouthernpart) None (transportfromsouthernpart) Groundwater (Dugwell) Groundwater (Handpump) Tap water Groundwater (Handpump) Groundwater (Handpump) Groundwater (Handpump) Groundwater (Handpump) Groundwater (Handpump) Groundwater (Handpump) Groundwater (Handpump) Groundwater (Dugwell) Tap water Groundwater (Handpump) Groundwater (Handpump) Groundwater (Handpump) Groundwater (Handpump) Groundwater (Dugwell) Groundwater (Handpump) drinking water Source of - - - - 50 60 8 22 90 6 50 50 100 45 Total householdinvillage hence itoccupies allthegeologicalandgeomorphic units. The studyareaiselongated innorth-southdirectionand 3.5 Hydrogeology oftheStudyArea household withdrinkingwaterfacility(Table3). explored basedonthetotalhouseholdandnumberof ter quality, the actual availability of drinking water has been In addition to the usage of different sources of water and wa 3.4 DrinkingWaterFacility is havingrelativelygoodavailability ofdrinkingwater. mari inthesouthtoSukhahol andPeltimariinthenortheast water availability.Thearealying betweenSanischarePelti western partofthearea(e.g.obs.Pt.3,4)ishavingdrinking 25 25 200 25 7 15 60 30 90 50 Not available Not available 9 months Year round 6 months Year round Year round 9 months 9 months Year round 9 months 9 months Year round 9 months Year round Year round 6 months Year round Year round Year round of Water Availability - - - 1 (4.0%) - 7 (46.7%) 50 (83.3%) 25 (83.3%) 80 (88.9%) 40 (80%) 45 (90.0%) 40 (66.6%) 8 (100%) - 32 (35.5%) 6 (100%) 12 (24.0%) 12 (24.0%) - 7 (15.5%) drinking waterfacility Households having - -

35 Geology NJST Pathak

The hydrogeological condition of the study area has been available for the study area. In order to have some informa- discussed with reference to the topography, surface geology tion regarding the lithological variation in the study area, lo- and sub-surface lithology, water table depth and occurrence cal people were consulted who were present during the con- of groundwater at different localities. struction of dug well or hand pumps. Based on the reported log and observations at sections along the river bank, the 3.5.1 Lithological description typical lithological logs of the Bhabar Zone, Middle Terai and The lithological logs of tube wells (shallow and deep) are not Southern Terai are drawn (Fig. 8).

Fig. 7. Sources of water in the study area

Fig. 8. Typical lithological logs of (a) Bhabar Zone, (b) Middle Terai, and (c) Southern Terai

36 Nepal Journal of Science and Technology , 17(1), 2016, pp. 31-38 Nepal Journal of Science and Technology Original Article Table 4:Watertabledepth(mbgl)inthestudyarea (Rao andPathak 1996,Raoetal.1996). typical ofthesituationin recharge zoneofNepaleseTerai the presence of thick sequence of coarser materials. This is the northernandwesternpart ofthestudyareaindicates south oftheSiwalikHills(Fig. 9).Thedeeperwatertablein The watertablemapisprepared onlyforthearealying 19 18 17 16 15 14 13 11 20 10 9 8 7 6 5 4 3 2 1 S. N. ing totheBhabarZonewhileitislessatsouthernpart. The watertabledepthismoreatthenorthernpartbelong The watertabledepthvariesfrom3to8.5mbgl(Table4). The watertabledepthwasassessedat19observationpoints. 3.5.2 Watertable below. horizon atthetop(0-5mbgl)followedbysandandgravel Bhabar zone,thatisrepresentedbythepresenceofclay point 18liesintheMiddleTerai,immediatelysouthof around 5.5mdepthandcoarsersandbelow.Theobservation represented bythepresenceofclayandclayeysandupto north andMiddleTeraiinthesouth.Theselocationsare of the study area falls near the border of Bhabar Zone in the 30. Theobservationpoints1,2,3,and4inthewesternpart observation point27andbelow21min boulders havebeenreportedbelowthedepthof9min the wells,saturatedcoarsesandandgravelaswellsome the BhabarZone(RaoandPathak1996).However,inboth clay horizoniscommonininter-streamarealyingwithin the studyarea.Theoccurrenceofsuchthickclayandsandy inter-stream areaoftworiversinthenorth-eastern part of Zone.However, the observationpoints27and30thatarelyingwithin Bhabar the in thick sequenceofclayandsandywasdepictedfrom falling area the confirm westernmost part of the study area, near Bidhuwa Khola, has beenreportedfromobservationpoints5and6inthe the occurrenceofbouldersbelowdeptharound13m 1.5 m(e.g.Obs.Pts.23-25)inthesouthernpart.Likewise, sequence of coarser materials below the depth of around fall withintheBhabarZone,whichisindicatedbythick which show that observation points 22, 23, 24, 25, 27 and 30 the in study area(Obs.Pts.1,2,3,4,5,6,18,22,23,24,25,27and30), locations different 13 at drawn were litho-logs The The southward fining nature of the sediments has the sediments of nature fining southward The 31 30 27 25 24 23 22 19 18 17 8 6 5 4 3 2 1 Obs. Point Khalbale Tole-6 Jimali Tole-6 Laxmi Chowk-6 Kirateshowr Sec.School-6 Bagaiche Tole-6 Tidio Tole-6 Chulachuli VDC,W.No.7 Satpatre-7 Chulachuli VDC,W.No.7 Unsathi PariwarTole-7 Talo Santichowk-7 Chulachuli VDC,W.No.7 Jogi Tole-7 Bidhuwa dill-7 Tumruk Tole-7 Tumruk Tole-7 Tumruk Tole-7 Santi Chowk-7 depth(mbgl) Village-Ward NoWaterTable 2.66 7.61 4.57 3.96 3.65 3.04 3.65 3.50 0.00 0.30 0.30 0.61 7.32 8.53 3.96 3.96 0.71 3.65 - 4. Conclusions clays (PathakandRao1998). zone lying in the south that is represented by thick layer of recharge zoneinthenorth is betterthanatthedischarge The physicalandchemicalquality ofthegroundwaterat fer materialsinsuchregionishigh(RaoandPathak1996). and elevation. The hydraulic conductivity of the shallow aqui the springlinesoccurredduetochangeinsedimentsize The southernboundaryoftheBhabarZoneisdemarcated by is occupiedbytherechargezoneforentiresouthernpart. around 56% of the study area, indicating that significant area subsurface rechargingthesouthernpart.Thiszoneoccupies lose significant amount of its discharge, which gradually flow these coarser sediments, the rivers flowing through this zone is narrowintheinter-streamarea.Becauseofthicklayer of Bhabar Zonebecomeswideraroundthemajorriverswhile it debouching southwardfromthemountainousregion.The vium (alongthefoothill)oralluviumdepositedbyrivers The coarser sediments of the Bhabar Zone are either collu 3.5.4 Groundwater recharge out anynoticeableodor. area isfreeofironcontentandhavinggoodtastewith Likewise, thewatersuppliedthroughspringsinhilly ence ofthickblackclaylayerattheupperpartaquifer. iron contentinthegroundwater.Thisisbecauseofpres significant of consists area study the of part southern the in zone. Observationpoints17,18,20,22,23and24mostlylying in adugwellobservationpoint31thatliestheBhabar tion ofpresenceiron(Table5).Turbidwaterwasobserved water quality is good in most of the places with some excep tion ofironcontentwasmadethroughtheobservation.The The physicalqualityofwaterhadbeenassessedandestima 3.5.3 Waterquality is tooshallow(e.g.ObservationPoint19). occurrence ofspringlineandhencewatertableatthisplace of theBhabarZoneandMiddleTeraiisdemonstratedby resulted inthepresenceofshallowwatertable.Theborder The demarcation ofSiwalikRegion,Bhabar Zoneand Fig. 9.Watertablemapofthestudyarea ------

37 Geology NJST Pathak

Table 5: Water quality in the study area

S. N. Obs. Point Village-ward No. Source of drinking water Quality of water 1 1 Santi Chowk-7 Groundwater (Hand pump) Good quality 2 2 Tumruk Tole-7 Groundwater (Dug well) Good quality 3 3 Tumruk Tole-7 Groundwater (Hand pump) Good quality 4 4 Tumruk Tole-7 Groundwater (Hand pump) Good quality 5 5 Bidhuwa dill-7 Groundwater (Hand pump) Good quality 6 6 Jogi Tole-7 Groundwater (Hand pump) Good quality 7 7 Padam chowk-7 Tap water Good quality 8 17 Talo Santi chowk-7 Groundwater (Dug well) Iron content 9 18 Unsathi Pariwar Tole-7 Groundwater (Hand pump) Iron content 10 20 Satpatre-7 Groundwater (Hand pump) Iron content 11 22 Chulachuli VDC, W. No. 7 Groundwater (Hand pump) Iron content 13 23 Tidio Tole-6 Groundwater (Hand pump) Iron content 14 24 Bagaiche Tole-6 Groundwater (Hand pump) Iron content 15 25 Kirateshowr Groundwater (Hand pump) Secondary School-6 Good quality 16 27 Laxmi Chowk-6 Groundwater (Hand pump) Good quality 17 29 Janta Tole-6 Tap water Good quality 18 30 Jimali Tole-6 Groundwater (Hand pump) Good quality 19 31 Khalbale Tole-6 Groundwater (Dug well) Turbid

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