[en] In the central part of the semi-arid Dargol Basin of southwestern Niger, most of the groundwater resource is contained in the fractured aquifers of the Precambrian basement. The groundwater resource is poorly characterized and this study is the first attempt to better describe the recharge mechanisms and hydrogeochemical behaviour of the aquifers. Hydrogeochemical and piezometric methods were combined to determine changes in recharge rate and origin of groundwaters for the shallow weathered aquifer and the deep fissured/fractured aquifer. At the basin scale, the groundwater fluxes towards the Niger River are influenced mainly by topography, with no visual long-term trend in groundwater levels (1980-2009). The hydro-geochemical signature is dominated by the calcic-bicarbonate to magnesian (70%) type. It shows evolution from an open environment with CO2 and low mineralized water (granitoids, alterites) towards a more confined environment with more mineralized waters (schists). Stable water isotopes (δ18O, δ2H) analysis suggests two main groundwater recharge mechanisms: (i) direct recharge with nearly no post-rainfall fractionation signature and (ii) indirect recharge from evaporated surface waters and/or stream-channel beds. Groundwater tritium content indicates that recharge is mostly recent, with an age less than 50 years (3H > 3 TU), with only 10% indicating low or even no recharge for the past decades. A median value of the groundwater renewal rate estimated from individual values of tritium is equivalent to 1.3% y-1, close to the one determined for groundwater samples dating to the early 1980s, thus indicating no measurable long-term change.
Disciplines :
Géologie, ingénierie du pétrole & des mines
Auteur, co-auteur :
Abdou Babaye, Maman Sani ; Université Dan DickoDankoulodo de Maradi, Maradi (Niger) > Faculté des Sciences et Techniques, UMR SERMUG > Département de Géologie
Orban, Philippe ; Université de Liège - ULiège > Département ArGEnCo > Hydrogéologie & Géologie de l'environnement
Ousmane, Boureisma; Université Abdou Moumouni, Niamey (Niger) > Faculté des Sciences et Techniques > Département de Géologie
Favreau, Guillaume; IRD, Université de Montpellier, France > UMR HydroSciences
Brouyère, Serge ; Université de Liège - ULiège > Département ArGEnCo > Hydrogéologie & Géologie de l'environnement
Dassargues, Alain ; Université de Liège - ULiège > Département ArGEnCo > Hydrogéologie & Géologie de l'environnement
Langue du document :
Anglais
Titre :
Characterization of recharge mechanisms in a Precambrian basement aquifer in semi-arid south-west Niger
Abdalla OAE (2009) Groundwater recharge/discharge in semi-arid regions interpreted from isotope and chloride concentrations in North White Nile rift, Sudan. Hydrogeol J 17:679–692. 10.1007/s10040-008-0388-9
Abdou Babaye MS (2012) Evaluation des ressources en eau souterraine dans le bassin de Dargol (Liptako–Niger) [Groundwater resources estimates in the River Dargol basin (Liptako, Niger)]. PhD Thesis Univ. Liège, Belgium, 235 pp
Abdou A, Bonnot H, Bory K, Chalamet D, St Martin M, Younfa I (1998) Notice explicative des cartesgéologiques du Liptako à 1/100 000 et 1/200 000 [Explanatory note of the geological maps of the Liptako region at scales of 1/100,000 and 1/200,000]. Ministry of Mines and Energy, Niamey, Niger, 64 pp
Acheamponga SY, Hess JW (2000) Origin of the shallow groundwater system in the southern Voltaian Sedimentary Basin of Ghana: an isotopic approach. J Hydrol 233:37–53
Adiaffi A, Marlin C, Oga YMS, Massault M, Noret A, Biemi J (2009) Palaeoclimatic and deforestation effect on the coastal fresh groundwater resources of SE Ivory Coast from isotopic and chemical evidence. J Hydrol 369:130–141
Affaton P, Gaviglio P, Pharisat A (2000) Réactivation du craton Ouest-africain au Panafricain: paléocontraintes déduites de la fracturation des grès néoprotérozoïques de Karey Gorou (Niger, Afrique de l’Ouest) [Reactivation of the West-African craton during the Panafrican tectonic cycle: evidence of paleostresses recorded by brittle deformation in the Neoproterozoic sandstones of KareyGorou (Niger, West Africa)]. C R Sci Acad Paris 331:609–614
Aggarwal, P. K., Gat J. R. and K. F. O Froehlich (eds) (2005) Isotopes in the water cycle: past, present and future of a developing science. Springer, Dordrecht, The Netherlands
Amani A, Nguetora M (2002) Evidence d’une modification du régime hydrologique du fleuve Niger à Niamey [Evidence of a change in the hydrological regime of the river Niger in Niamey]. IAHS Publ 274, IAHS, Wallingford, UK, pp 449–456
Aranyossy JF, Gaye CB (1992) Use of the tritium thermonuclear peak in the deep unsaturated zone for quantitative estimate of aquifer recharge under semiarid conditions: first application in the Sahel. CR Acad Sci Paris 315(Ser II):637–643
Bajjali W (2008) Evaluation of groundwater in a three-aquifer system in Ramtha area, Jordan: recharge mechanisms, hydraulic relationship and geochemical evolution. Hydrogeol J 16:1193–1205
Ball LB, GeS, Caine JS, Revil A, Jardani A (2010) Constraining fault-zone hydrogeology through integrated hydrological and geoelectrical analysis. Hydrogeol J 5:1057–1067
Bouragba L, Mudry J, Bouchaou L, Hsissou Y, Krimissa M, Tagma T, Michelot JL (2011) Isotopes and groundwater management strategies under semi-arid area: case of the Souss upstream basin (Morocco). Appl Radiat Isot 69(2011):1084–1093
Clark ID (2015) Groundwater geochemistry and isotopes. CRC Press, Boca Raton, FL
Clark I, Fritz P (1997) Environmental isotopes in hydrogeology. CRC Press, Boca Raton, 328 p
Cook P, Dogramaci S, McCallum J, Hedley J (2017) Groundwater age, mixing and flow rates in the vicinity of large open pit mines, Pilbara region, northwestern Australia. Hydrogeol J 25:39–53
De La Vaissière R (2006) Etude de l’aquifère néogène du Bas-Dauphiné: apports de la géochimie et des isotopes dans le fonctionnement hydrogéologique du bassin de Valence (Drôme, Sud-Est de la France) [Study of the Neogene aquifer of the lower Dauphiné region: contribution of geochemistry and isotopes approaches in the hydrogeological functioning of the Valence basin (Drôme, southeastern France)]. PhD Thesis, University of Avignon and the Vaucluse region, France, 339 pp
De Vries JJ, Simmers I (2002) Groundwater recharge: an overview of processes and challenges. Hydrogeol J 1:5–17
Desconnets JC, Taupin JD, Lebel T, Leduc C (1997) Hydrology of the Hapex-Sahel central super-site: surface water drainage and aquifer recharge through the pool systems. J Hydrol 188:155–178
Dewandel B, Lachassagne P, Wyns R, Maréchal JC, Krishnamurthy NS (2006) A generalized 3-D geological and hydrogeological conceptual model of granite aquifers controlled by single or multiphase weathering. J Hydrol 330:260–284
Diaw M (2008) Approche hydrochimique et isotopique de la relation eau de surface/nappe et du mode de recharge de la nappe alluviale dans l’estuaire et la basse vallée du fleuve Sénégal: identification des zones inondées par télédétection et par traçage isotopique [Hydrodynamics and isotopic approaches of the relationships between surface and groundwaters and of the recharge processes of the alluvial aquifer in the downstream part of the Senegal River: identifying flooded areas by remote sensing and isotopic tracers]. PhD Thesis, Univ. C.A. Dakar, Senegal, 178 pp
Diop S, Tijani MN (2008) Assessing the basement aquifers of eastern Senegal. Hydrogeol J 16:1349–1369. 10.1007/s10040-008-0353-7
Dupuis D, Pons J, Prost AE (1991) Mise en place de plutons et caractérisation de la déformation birimienne au Niger occidental [Plutonic emplacement and Birimian deformation in western Niger]. CR Acad Sci Paris 312(II):769–776
Edmunds WM, Fellman E, Goni IB, Prudhomme C (2002) Spatial and temporal distribution of groundwater recharge in northern Nigéria. Hydrogeol J 10:205–215
Favreau G, Leduc C, Marlin C, Guero A (2002) A rising piezometric depression in the Sahel (southwestern Niger). C R Geosci 334:395–401
Favreau G, Cappelaere B, Massuel S, Leblanc M, Boucher M, Boulain N, Leduc C (2009) Land clearing, climate variability, and water resources increase in semiarid Southwest Niger: a review. Water Resour Res 45:W00A16. 10.1029/2007WR006785
Favreau G, Nazoumou Y, Leblanc M, Guéro A, Goni IB (2012) Groundwater ressources increase in the Iullemmeden Basin, chap 7. In: Climate change effects on groundwater resources:a global synthesis of findings and recommendations, vol 27. Taylor and Francis, London, pp 113–128
Filippi C, Milville F, Thiery D (1990) Evaluation of natural recharge to aquifers in the Sudan-Sahel climate using global hydrological modelling: application to ten sites in Burkina Faso. Hydrol Sci J 35:29–48
Gardelle J, Hiernaux P, Kergoat L, Grippa M (2010) Less rain, more water in ponds: a remote sensing study of the dynamics of surface waters from 1950 to present in pastoral Sahel (Gourma region, Mali). Hydrol Earth Syst Sci 14:309–324
Gaultier G (2004) Recharge et paléorecharge d’une nappe libreen milieu sahélien (Niger Oriental): approches géochimique et hydrodynamique [Recharge and paleorecharge of a superficial aquifer in the Sahel (southeast Niger): geochemistry and hydrodynamic approaches]. PhD Thesis, Univ. Paris Sud, France, 179 pp
Girard P (1993) Techniques isotopiques ( 15 N, 18 O) appliquées à l’étude des nappes des altérites et du socle fracturé de l’ouest africain: étude de cas—l’Ouest du Niger [Isotopic techniques ( 15 N, 18 O) applied for groundwater in alterites and hard rock aquifers of West Africa: case study—West Niger]. PhD Thesis, Univ. Québec à Montréal, Canada, 141 pp
Girard P, Hillaire-Marcel C, Oga MS (1997) Determining the recharge mode of Sahelian aquifers using water isotopes. J Hydrol 197:189–202
GNIP (2011) Global network of isotopes in precipitation. http://www-naweb.iaea.org/napc/ih/IHS_resources_isohis.html. Accessed January 2018
Goni IB (2006) Tracing stable isotope values from meteoric water to groundwater in the southwestern part of the Chad basin. Hydrogeol J 14:742–752
Goni IB, Fellman, Edmunds WM (2001) Rainfall geochemistry in the Sahel region of northern Nigeria. Atmos Environ 35:4331–4339
Guéro A (2003) Étude des relations hydrauliques entre les différentes nappes du complexesédimentaire de la bordure sud-ouest du bassin des Iullemmeden (Niger): approches géochimique et hydrodynamique [Study of hydraulic relationships between the different aquifers of the sedimentary complex of the southwestern border of the Iullemmeden basin (Niger): hydrodynamics and geochemical approaches]. PhD Thesis, Univ. Paris XI Orsay, France, 265 pp
Ibrahim M, Favreau G, Scanlon BR, Seidel IC, Le Coz M, Demarty J, Cappelaere B (2014) Long-term increase in diffuse groundwater recharge following expansion of rainfed cultivation in the Sahel, West Africa. Hydrogeol J. 10.1007/s10040-014-1143-z
INS (2012) Présentation des résultats préliminaires du quatrième recensement général de la population et de l’habitat (RGP/H) [Presentation of the preliminary results of the 4th general census of the population and living conditions (RGP/H)]. INS, Niamey, Niger, 9 pp
L’Hôte Y, Mahé G, Some B, Triboulet JP (2002) Analysis of a Sahelian annual rainfall index from 1896 to 2000: the drought continues. Hydrol Sci 47:56–572
Lapworth DJ, MacDonald AM, Tijani MN, Darling WG, Gooddy DC, Bonsor HC, Araguás-Araguás LJ (2013) Residence times of shallow groundwater in West Africa: implications for hydrogeology and resilience to future changes in climate. Hydrogeol J 21(3):673–686. 10.1007/s10040-012-0925-4
Le Gal La Salle C, Marlin C, Leduc C, Massault M, Favreau G (2001) Renewal rate estimation of groundwater based on radioactive tracers ( 3 H et 14 C) in an unconfined aquifer an a semi-arid area, Iullemede Basin. Niger J Hydrol 254:145–156
Leblanc M, Favreau G, Massuel S, Tweed S, Loireau M, Cappelaere B (2008) Land clearance and hydrological change in the Sahel: SW Niger. Glob Planet Chang 61(4):135–150
Leduc C, Taupin J-D, Le Gal La Salle C (1996) Estimation de la recharge de la nappe phréatique du Continental Terminal (Niamey, Niger) à partir des teneurs en tritium [Recharge of the Continental Terminal water-table (Niamey, Niger) estimated from tritium measurements and modelling]. C R Acad Sci Paris 323(Série II a):599–605
Leduc C, Sabljak S, Taupin J-D, Marlin C, Favreau G (2000) Estimation de la recharge de la nappe quaternaire dans le Nord-Ouest du bassin du lac Tchad (Niger oriental) à partir de mesures isotopiques [Recharge of the Quaternary water table in the northwestern Lake Chad basin (southeastern Niger) estimated from isotopes]. CR Acad Sci Paris 330:355–361
Leduc C, Favreau G, Schroeter P (2001) Long-term rise in a Sahelian water-table: the continental terminal in South-West Niger. J Hydrol 243:43–54
Machens E (1973) Contribution à l’étude des formations du socle cristallin et de la couverture sédiementaire de l’Ouest de la République du Niger. Mémo [Contribution to the study of the formations of the crystalline basement and the sedimentary cover of the West of the Republic of Niger. Memo] No. 82, BRGM, Orléans, France, 167 pp
Mahé G (2009) Surface/groundwater interactions in the Bani and Nakambe rivers, tributaries of the Niger and Volta basins, West Africa. Hydrol Sci 54(4):704–712
Mahé G, Leduc C, Amani A, Paturel JE, Girard S, Servat E, Dezetter A (2003) Augmentation récente du ruissellement de surface en région soudano-sahélienne et impact sur les ressources en eau [Recent increase in runoff in the Sudano-Sahelian region and its impact on water resources]. In: Hydrology of Mediterranean and semiarid regions. IAHS Publ. 278, IAHS, Wallingford, UK, pp 215–222
Massing O, Tang Z (2010) Recharge of the Quaternary aquifer of Lake Chad Basin estimated from Oxygen-18 ( 18 O) and tritium ( 3 H) isotopes. Am Sci 6(9):283–292
McDonnell J (2017) Beyond the water balance. Nat Geosci 10. www.nature.com/naturegeoscience. Accessed December 2017
Ngounou Ngatcha B, Mudry J, Wakponou A, Ekodeck GE, Njitchoua R, Sarrot-Reynaul J (2001) Le cordon sableux Limani-Yagoua, extrême-Nord Cameroun, et son rôlehydraulique [The Limani-Yagoua sandy belt, far North Cameroon, and its hydraulic role]. J Afr Earth Sci 32(4):889–898
Nicholson SE (2001) Climatic and environmental change in Africa during the last two centuries. Clim Res 17:123–144
Nkotagu (1996) Origins of high nitrate in groundwater in Tanzania. J Afr Earth Sci 21(4):471–478
Ousmane B (1988) Étude géochimique et isotopique des aquifères du socle de la bande sahélienne du Niger (Liptako, Sud-Maradi, Zinder-Est) [Geochemical and isotopic study of the basement aquifers of the Sahelian belt of Niger (Liptako, South Maradi, East Zinder]. PhD Thesis, Univ. Niamey, Niger, 175 pp)
Ousmane B, Fontes JC, Aranyossy JF, Joseph A (1983) Hydrologie isotopique et hydrochimie des aquifères discontinus de la bande sahélienne et de l’Aïr (Niger) [Isotope hydrology of the discontinuous aquifers of the Sahelian belt and the Aïr (Niger)]. In: Isotope hydrology, 1983, IAEA, Vienna, pp 367–395
Ousmane B, Galadima S, Moumouni A, Soumana I (2012) La qualité physico-chimique des eaux des aquifères discontinus du socle du Département de Téra (Liptako, Niger): impacts Sur les taux de desserte en eau potable des populations rurales au Sahel [Physico-chemical quality of water in basement discontinuous aquifers of the department of Tera (Liptako, Niger): impacts on the drinkable water supply rates in Sahel rural areas]. Africa Geosci Rev 19(1):1–16
Panthou G, Vischel T, Lebel T (2014) Recent trends in the regime of extreme rainfall in the Central Sahel. Int J Climatol 34:3998–4006. 10.1002/joc.3984
Rana SS (1998) Application of directional filtering in lineament mapping for groundwater prospecting around Bhinmal: a semi arid part of Thar Desert. J Indian Soc Remote Sensing 26(1-2):35–44
Sagna P, Ndiaye O, Diop C, Niang AD, Sambou PC (2015) Les variations récentes du climat constatées au Sénégal sont-elles en phase avec les descriptions données par les scénarios du GIEC [Are recent climate variations observed in Senegal in conformity with the descriptions given by the IPCC scenarios]? Pollut Atmos 227:1–17
Saravana KU, Suman S, Navada SV, Deodhar AS (2009) Environmental isotopes investigation on recharge processes and hydrodynamics of the coastal sedimentary aquifers of Tiruvadanai, Tamilnadu state. India J Hydrol 364:23–39
Scanlon BR, Keese KE, Flint AL, Flint LE, Gaye CB, Edmunds WM, Simmers I (2006) Global synthesis of groundwater recharge in semiarid and arid regions. Hydrol Process 20:3335–3370
Schiewede M, Duijnisveld WHM, Böttcher J (2005) Investigation of processes leading to nitrate enrichment in soils in the Kalahari region, Botswana. Phys Chem Earth 30:712–716
Séguis L, Cappelaere B, Milesi G, Peugeot C, Massuel S, Favreau G (2004) Simulated impacts of climate change and land-clearing on runoff from a small Sahelian catchment. Hydrol Process 18:3401–3413. 10.1002/hyp.1503
Solder JE, Stolp BJ, Heiweil VM, Susong DD (2016) Characterization of mean transit time at large springs in the upper Colorado River basin, USA: a tool for assessing groundwater discharge vulnerability. Hydrogeol J 24:2017–2033
Soumaila A, Konate M (2005) Caractérisation de la déformation dans la ceinture birimienne (paléoprotérozoïque) de Diagorou-Darbani (Liptako nigérien, Afrique de l’Ouest) [Characterization of the deformation in the Birimian belt (Paleoproterozoic) of the Diagorou-Darbani (Niger Liptako, West Africa)]. African Geosci Rev 12(3):161–178
Stadler S, Osenbrück K, Suckow AO, Himmelsbach T, Hötzl H (2010) Groundwater flow regime, recharge and regional-scale solute transport in the semi-arid Kalahari of Botswana derived from isotope hydrology and hydrochemistry. J Hydrol 388:291–303
Taupin J-D, Gaultier G, Favreau G, Leduc C, Marlin C (2002) Variabilité isotopique des précipitations sahéliennes à différentes échelles de temps à Niamey (Niger) entre 1992 et 1999: implication climatique [Isotopic variability of Sahelian rainfall at different time steps in Niamey (Niger, 1992–1999): climatic implications]. C R Geosci 334:43–50
Taupin J-D, Gaultier G, Favreau G, Leduc C, Ramirez E (2003) Étude isotopique des précipitations sahéliennes à l’échelle de l’événement: relation avec les paramètres météorologiques et le type de précipitation [Isotopic study of Sahelian rainfall at the event scale: relationship with meteorological parameters and rainfall characteristics]. Hydrol Mediterranean Semiarid Regions 278:179–185
Taylor C, Lambin E, Stephenne N, Harding R, Essery R (2002) The influence of land use change on climate in the Sahel. J Clim 15:3615–3629
Tremoy G, Vimeux F, Mayaki S, Souley I, Cattani O, Risi C, Favreau G, Oï M (2012) A 1-year long d 18 O record of water vapor in Niamey (Niger) reveals insightful atmospheric processes at different timescales. Geophys Res Lett 39:L08805, 5 pp. 10.1029/2012GL051298
Yaméogo OS (2008) Ressources en eau souterraine du centre urbain de Ouagadougou au Burkina Faso, qualité et vulnérabilité [Groundwater resources in the urban center of Ouagadougou in Burkina-Faso, quality and vulnerability]. PhD Thesis, University of Avignon and the Vaucluse region, France, Univ. Ouagadougou, Burkina Faso, 245 pp
