Estimating specific yield and transmissivity with magnetic resonance sounding in an unconfined sandstone aquifer (Niger)

Boucher, Marie; Favreau, Guillaume; Vouillamoz, Jean‐Michel; Nazoumou, Yahaya; Legchenko, A.

doi:10.1007/s10040-009-0447-x

Cited by 62 publications

(67 citation statements)

References 25 publications

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“…References suggesting how uncertainty of transmissivity (or hydraulic conductivity) can be estimated from MRS are numerous (e.g., Legchenko et al, 2004;Chalikakis et al, 2008;Plata and Rubio, 2008;Boucher et al, 2009;Günther and Müller-Petke, 2012;Vilhelmsen et al, 2014) but the methods or their documentation are often incomplete. In some references, it is just stated that the uncertainty given for the MRS-estimated transmissivities takes into account the uncertainty of the MRS data, MRS parameters, and transmissivity estimates (Legchenko et al, 2004;Boucher et al, 2009), but the method is not documented or explained. Chalikakis et al (2008) estimate the uncertainty of the MRS-based transmissivity estimates, but they only seem to take equivalent solutions into account.…”

Section: Introductionmentioning

confidence: 99%

On determining uncertainties of magnetic resonance sounding estimated transmissivities for groundwater modeling

2016

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The nuclear magnetic resonance sounding (MRS) method is used increasingly as a tool for hydrological investigations. Compared to other geophysical methods, the advantage of MRS is that it is directly sensitive to the presence of water in the subsurface. Data interpretations can also be used to get information about the subsurface pore structures, which under special conditions can be related to hydraulic properties such as aquifer transmissivity. However, to broaden the usage of this information in hydrological modeling, the uncertainties related to these transmissivity estimates must be determined. Otherwise, properly balanced weights cannot be given to the prior information obtained from MRS transmissivity estimates as compared to the hydrological data sets when used for groundwater model calibration. We have developed a methodology to estimate the uncertainties of MRS-based transmissivity estimates. Compared to previous studies, the methodology is well defined, and it takes into account important factors such as the uncertainties of the hydraulically estimated transmissivities, the uncertainty of the correlation factor in the petrophysical relation, and the uncertainties and correlations of the geophysically estimated parameters. We have determined the correlations and uncertainties of the geophysical parameters using a linear and a nonlinear method, and we find that the results are comparable.

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Section: Introductionmentioning

confidence: 99%

On determining uncertainties of magnetic resonance sounding estimated transmissivities for groundwater modeling

2016

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“…Transmissivity is a highly variable parameter, it often varies dramatically and exhibits large fluctuations. It is rarely feasible to obtain enough measurements to fully characterize an aquifer (Painter et al, 2007;Boucher et al, 2009). This variability in space can be explained by the fact that the aquifers are often heterogeneous.…”

Section: Introductionmentioning

confidence: 99%

Improvement of aquifer transmissivity assessment in crystalline and metamorphic fractured rocks in Bondoukou area, North-Eastern Côte d’Ivoire

Lasm¹,

Youan²

2012

AJSIR`

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This study is performed in the Bondoukou area located in north-eastern Côte d'Ivoire. The aim of this study was to improve the assessment of transmissivity of the highly fractured aquifers of Bondoukou area using kriging techniques. A previous estimation of the transmissivity was conducted with aquifer transmissivity of crystalline rocks (n = 62). These transmissivities were later supplemented by 78 samples of aquifer transmissivity of metamorphic rocks. The results of this study were compared with those obtained in crystalline rock aquifers. In both cases, the variogram exhibits a large nugget effect representing respectively 63 and 70% of total dispersion. The nugget effect of this study is less important than the previous study. The range is equal to 12 km and is larger than that obtained in the previous study. The structuring of the variogram is enhanced when we consider the aquifer transmissivity of metamorphic rocks. Transmissivity estimated in both studies varies between 4.00E-06 and 1.72 E-06 E-05 m 2 .s -1 and between 3.86 E-06 and 1.84 E-05 m 2 .s -1 respectively in the previous study and in this study. In both cases, the observed and estimated transmissivities values are comparable and are spread over two orders of magnitude. Kriging maps showed that the estimation of transmissivity in Bondoukou area is better in this study. The results obtained in this study are interesting because they showed improved estimate of the transmisssivity in the Bondoukou area.

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“…The MRS survey provides θ MRS , which is an estimate of the free water content (θ f ) that is composed of both extractable, gravitational water and immobile, non-extractable capillary water (Lubczynski and Roy, 2007). Thus neither S y nor S e are equivalent to θ MRS although there are empirical relations between them Roy, 2004, 2007;Vouillamoz et al, 2007;Boucher et al, 2009b;Vouillamoz et al, 2012b). In this study, to calculate unconfined and confined storage parameters we used the empirical Equations (4.6) and (4.7) respectively (Vouillamoz et al, 2007):…”

Section: Magnetic Resonance Sounding Methodsmentioning

confidence: 99%

“…Boucher et al (2009b) suggested that for such low values of Θ MRS the linearity of the equation is fairly well maintained but for larger Θ MRS the relationship is not always perfectly linear. Because the Carrizal study area is relatively small and hydraulically uniform, it can be assumed that the variability of the specific yield is well resembled by the 12 MRS surveys available.…”

Section: Mrs Data Processingmentioning

confidence: 99%

“…The MRS technique is already known and well accepted as non-invasive, quantitative evaluation of water in subsurface rather than prospecting hydrogeophysical tool. More information about principles of the MRS technique with emphasis on quantification of groundwater resources can be found in: Lubczynski and Roy (2003); Roy and Lubczynski (2003); Roy (2004, 2007); Rubio (2007, 2008); the parameterization of aquifers in Roy (2005, 2007); Vouillamoz et al (2007);Boucher et al (2009b);Vouillamoz et al (2012b); and parameterization of unsaturated zone in Roy and Lubczynski (2005); Mohnke and Yaramanci (2008);Walsh et al (2014).…”

Section: Introductionmentioning

confidence: 99%

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Integration of hydrogeophysics and remote sensing with coupled hydrological models

Francés¹

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Estimating specific yield and transmissivity with magnetic resonance sounding in an unconfined sandstone aquifer (Niger)

Cited by 62 publications

References 25 publications

On determining uncertainties of magnetic resonance sounding estimated transmissivities for groundwater modeling

On determining uncertainties of magnetic resonance sounding estimated transmissivities for groundwater modeling

Improvement of aquifer transmissivity assessment in crystalline and metamorphic fractured rocks in Bondoukou area, North-Eastern Côte d’Ivoire

Integration of hydrogeophysics and remote sensing with coupled hydrological models

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