Understanding groundwater systems and their functioning through the study of stable water isotopes in a hard-rock aquifer (Maheshwaram watershed, India)

Négrel, Philippe; Pauwels, Hélène; Dewandel, Benoı̂t; Gandolfi, Jean-Marie; Mascre, C.; Ahmed, Shakeel

doi:10.1016/j.jhydrol.2010.11.033

Cited by 77 publications

(25 citation statements)

References 37 publications

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“…In order to assess the seasonal effects on the chemical and isotopic composition of these waters, 16 samples were collected at the same locations during the two campaigns. In addition to groundwater surveys, 30 weekly rain waters were collected from March to October following the method described by Negrel et al (2011). Also, among the samples collected in the dry season, 10 samples were investigated for CFCs and SF 6 concentrations.…”

Section: Sample Collectionmentioning

confidence: 99%

A multi-tracer approach for assessing the origin, apparent age and recharge mechanism of shallow groundwater in the Lake Nyos catchment, Northwest, Cameroon

Kamtchueng

Fantong

Wirmvem

et al. 2015

Journal of Hydrology

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Keywords:Stable isotopes (d 18 O and dD) CFCs and SF 6 Shallow groundwater origin and age Shallow groundwater recharge Lake Nyos -Cameroon s u m m a r yThe shallow aquifer in the vicinity of Lake Nyos (Northwest, Cameroon) is one of the main water supply sources to meet the water needs of the inhabitants to be resettled after 1986s tragedy. Unfortunately, there is a lack of knowledge on the groundwater recharge and flow systems in the area. Multiple environmental tracers (d 18 O, dD, Cl À , CFCs and SF 6 ) and a yearly record of rainfall, surface waters and groundwater were employed to characterize the recharge mechanism of the shallow groundwater seeping in the fractured rock of the Lake Nyos catchment (LNC). The d 18 O-dD relationship of the rainfall events gave the Nyos Meteoric Water Line: dD = 8.28 d 18 O + 11.87. Inland moisture vapor may have impacted the isotopic composition of original vapor masses from Gulf of Guinea prior to precipitation. Shallow groundwater in the LNC shows a similar trend of enrichment in 18 O and D as surface waters indicating a well-mixed aquifer. The proportions of surface waters and rainfall in the groundwater reservoir were 87% and 13%, respectively. The high annual recharge rate (941 mm/yr) and the seasonal variability in the isotopic signatures of groundwater indicate a renewable aquifer system. CFCs apparent ages-based piston flow model revealed a young age (average of 24 a.) of the groundwater in the LNC. SF 6 -based ages were biased young as compared to relatively younger than CFCs-based ages, implying an additional terrigenic production of SF 6 . The conceptual model for groundwater flow suggests that three main flow regimes, mainly controlled by the physical properties of the rock heterogeneities govern the movement of water in the aquifer. The piston flow model appears, however, to be the better model to explain the flow regime in the highly faulted and fissured area where recharge occurs ($1200-1600 masl). The rapid circulation and the low solubility lead to low mineralization. In the middle-lower area where waters circulate more in the weathered layer, exponential mixing model dominates, yielding more mineralized water. Downward to the valley, with prevailing gentle slope, interaction between surface and recently infiltrated groundwater better explain the observed similarity in the isotopic compositions and the mineralization of water.

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Section: Sample Collectionmentioning

confidence: 99%

A multi-tracer approach for assessing the origin, apparent age and recharge mechanism of shallow groundwater in the Lake Nyos catchment, Northwest, Cameroon

Kamtchueng

Fantong

Wirmvem

et al. 2015

Journal of Hydrology

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“…The hydrological studies to assess groundwater resources and develop sustainable management strategies require a variety of scientific information (IAEA 2006). These include groundwater origin, recharge mechanism, residence time (Clark and Fritz 1997;Njitchoua et al 1997;Kortatsi 2006;Goni 2006;Lapworth et al 2013), rate of recharge (Coplen et al 2000;IAEA 2006;Negrel et al 2011;Takounjou et al 2011) and timing of recharge (Mbonu and Travi 1994;Oga et al 2008;Taylor and Howard 1996). Besides chemical tracers, such information has been better provided by the use of oxygen ( 18 O) and hydrogen (D) isotopes (Acheampong and Hess 2000; Deshpande et al 2003;Goni 2006;Lapworth et al 2013), which are integral parts of the water molecule (Craig 1961;Clark and Fritz 1997;Gat 2010).…”

Section: Introductionmentioning

confidence: 99%

Shallow groundwater recharge mechanism and apparent age in the Ndop plain, northwest Cameroon

et al. 2015

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Knowledge of groundwater recharge and apparent age constitutes a valuable tool for its sustainable management. Accordingly, shallow groundwater (n = 72) in the Ndop plain has been investigated using the stable isotopes of oxygen ( 18 O) and hydrogen ( 2 H or D) and tritium ( 3 H) to determine the recharge process, timing and rate of recharge, and residence time. The shallow groundwater showed low variability in d18 O values (-2.7 to -4.1 %) and 3 H content (2.4-3.1 TU). The low variability suggests a similar origin, homogenous aquifer, good water mixing and storage capacity of the groundwater reservoir. Like surface water, a cluster of groundwater along the Ndop Meteoric Water Line (NMWL) and Global Meteoric Water Line indicates meteoric origin/recharge. The rainfall recharge occurs under low relative humidity conditions and negligible evaporation effect. About 80 % of the recharge is from direct heterogeneous/diffuse local precipitation at low altitude (\1,260 m) within the Ndop plain. Approximately 20 % is from high altitude precipitation (localised recharge) or is recharged by the numerous inflowing streams and rivers from high elevations. A homogenous cluster of d-values in groundwater (and surface water) between May and June monsoon rains on the NMWL suggests dominant recharge during these months. The recharge represents at least 16 % ([251 mm) of the annual rainfall (1,540 mm) indicating high annual recharge; high enough for development of the groundwater resource for agriculture. The 3 H content ([2.4 TU) in groundwater indicates post-1952 recharged water with an estimated residence time \30 years, suggesting short subsurface circulation, and subsequently a renewable aquifer.

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“…and agricultural demand (e.g. Ma et al, 2005;Négrel et al, 2011;Hamed et al, 2014). In this context, stable isotope (d 2 H and d 18 O) and major dissolved chemical compositions of groundwater in the Quaternary and Miocene aquifers were studied in order to discuss recharge sources, salinization, and mixing among aquifers and surface water bodies.…”

Section: Introductionmentioning

confidence: 99%

Insights from stable isotopes and hydrochemistry to the Quaternary groundwater system, south of the Ismailia canal, Egypt

Khalil

Tokunaga

Ahmed

2015

Journal of Hydrology

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Understanding groundwater systems and their functioning through the study of stable water isotopes in a hard-rock aquifer (Maheshwaram watershed, India)

Cited by 77 publications

References 37 publications

A multi-tracer approach for assessing the origin, apparent age and recharge mechanism of shallow groundwater in the Lake Nyos catchment, Northwest, Cameroon

A multi-tracer approach for assessing the origin, apparent age and recharge mechanism of shallow groundwater in the Lake Nyos catchment, Northwest, Cameroon

Shallow groundwater recharge mechanism and apparent age in the Ndop plain, northwest Cameroon

Insights from stable isotopes and hydrochemistry to the Quaternary groundwater system, south of the Ismailia canal, Egypt

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