Estimation of the sustainable yields of boreholes in fractured rock formations

Tonder, G. J. Van; Botha, J. F.; Chiang, Wen-Hsing; Kunstmann, Harald; Xu, Ye‐Shuang

doi:10.1016/s0022-1694(00)00369-3

Cited by 52 publications

(34 citation statements)

References 12 publications

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“…These methods, in addition to analytical methods such as Logan (1964), are collated, together with graphical plots (e.g. semi-log, log-log and derivatives), into the flow characteristic (FC) Excel spreadsheet developed by the Institute for Groundwater Studies in South Africa (Van Tonder et al, 2001). As a result, despite the fact that various consultants and contractors were used to conduct and analyse the pumping tests over a number of years within the GRIP project framework, all analyses were conducted using the FC-spreadsheet.…”

Section: Methods Of Analysismentioning

confidence: 99%

Evaluation of factors influencing transmissivity in fractured hard-rock aquifers of the Limpopo Province

Holland¹

2012

WSA

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Geologically-complex fractured aquifers underlie large parts of the semi-arid Limpopo Province where some of the greatest groundwater needs in South Africa occur. It is important to identify potentially high-yielding zones that can be targeted for water supply. The study covered 7 distinct groundwater regions within Limpopo Province, together covering about 63 500 km 2 . Results from over 4 000 pumping-test analyses indicated that geological setting (e.g. aureole of granitoids), proximity and orientation of dykes and lineaments and proximity of surface-water drainages may exert an influence on borehole productivity. Although dykes are poor groundwater targets, drilling dykes composed of dolerite may prove to be more successful. Lineaments striking perpendicular to the current maximum horizontal stress seem to be more favourable targets, which is inconsistent with the predicted regime. Due to the complex geological history, it is difficult to link open discontinuities to a distinct recent or past tectonic event. Regional stress-field data, as in this case, may not account for local, possibly highly significant, stress-field variations. The hydrogeological importance of several factors related to groundwater occurrence, can be used as a working reference for future groundwater-development programmes.

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Section: Methods Of Analysismentioning

confidence: 99%

Evaluation of factors influencing transmissivity in fractured hard-rock aquifers of the Limpopo Province

Holland¹

2012

WSA

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“…The results of methods used in the present study were compared to those achieved using the calibrated 3D numerical model developed by van Tonder et al (2001a) to verify the estimated sustainable yield of a fractured rock well (UO5). The geometry of the model was based on the hydraulic characteristics of the Karoo aquifer at the Campus Test Site, which were derived from data collected during an extensive field investigation.…”

Section: Analytical Techniquesmentioning

confidence: 99%

“…S3 of the ESM) to 90 days, 200 days, 1 and 2 years, reflecting pumping periods used in the present study, by Misstear and Beeson (2000) and by van Tonder et al (2001a) for the Karoo model and FC-method, respectively. The calculated specific capacity at the end of each pumping period was applied to the available drawdown of 6 m, producing yields of 0.69, 0.58, 0.51 and 0.44 L/s, respectively.…”

Section: Analytical Techniquesmentioning

confidence: 99%

“…No yields were directly predicted, because the results were achieved by fitting yield curves to existing operational data. Van Tonder et al (2001a) used derivative analysis and semi-analytical techniques to develop their flow characteristic method (FC-method) for estimating yields of wells in the layered, sedimentary rock (multi-porous) Karoo aquifer of South Africa. Using data from a test of well UO5 at an extensively monitored research test site, they conducted a numerical analysis to verify their model, where the available drawdown was related to the depth of a single, discrete horizontal fracture.…”

Section: Introductionmentioning

confidence: 99%

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Reliable yields of public water-supply wells in the fractured-rock aquifers of central Maryland, USA

Hammond¹

2017

Hydrogeol J

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Most studies of fractured-rock aquifers are about analytical models used for evaluating aquifer tests or numerical methods for describing groundwater flow, but there have been few investigations on how to estimate the reliable long-term drought yields of individual hard-rock wells. During the drought period of 1998 to 2002, many municipal water suppliers in the Piedmont/Blue Ridge areas of central Maryland (USA) had to institute water restrictions due to declining well yields. Previous estimates of the yields of those wells were commonly based on extrapolating drawdowns, measured during short-term singlewell hydraulic pumping tests, to the first primary water-bearing fracture in a well. The extrapolations were often made from pseudo-equilibrium phases, frequently resulting in substantially over-estimated well yields. The methods developed in the present study to predict yields consist of extrapolating drawdown data from infinite acting radial flow periods or by fitting type curves of other conceptual models to the data, using diagnostic plots, inverse analysis and derivative analysis. Available drawdowns were determined by the positions of transition zones in crystalline rocks or thin-bedded consolidated sandstone/limestone layers (reservoir rocks). Aquifer dewatering effects were detected by type-curve matching of step-test data or by breaks in the drawdown curves constructed from hydraulic tests. Operational data were then used to confirm the predicted yields and compared to regional groundwater levels to determine seasonal variations in well yields. Such well yield estimates are needed by hydrogeologists and water engineers for the engineering design of water systems, but should be verified by the collection of longterm monitoring data.

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“…La ségrégation extrême induite par la présence d'une faille s'accompagne de modifications considérables des comportements hydrauliques permanent et transitoire à l'échelle du réservoir, comme le rapportent un grand nombre d'études de cas dans la littérature hydrogéologique et pétrolière (e.g., Michalski et Britton, 1996 ;Labaume et al, 2000 ;Van Tonder et al, 2001 ;Van Tonder et al, 2002 ;Babiker et Gudmunsson, 2004 ;Seaton et al, 2005 ;Gierczak et al, 2006). Ces modifications sont telles que, dans une majorité de cas, les comportements transmis par les milieux failles (et discontinus en général) ne peuvent être reproduits de manière satisfaisante par les modèles interprétatifs conventionnels.…”

Section: Introduction Generaleunclassified

Comportement hydraulique des milieux faillés /

Rafini¹

2008

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UIUQAC Mise en garde/AdviceAfin de rendre accessible au plus grand nombre le résultat des travaux de recherche menés par ses étudiants gradués et dans l'esprit des règles qui régissent le dépôt et la diffusion des mémoires et thèses produits dans cette Institution, l'Université du Québec à Chicoutimi (UQAC) est fière de rendre accessible une version complète et gratuite de cette oeuvre.Motivated by a desire to make the results of its graduate students' research accessible to all, and in accordance with the rules governing the acceptation and diffusion of dissertations and theses in this Institution, the Université du Québec à Chicoutimi (UQAC) is proud to make a complete version of this work available at no cost to the reader.L'auteur conserve néanmoins la propriété du droit d'auteur qui protège ce mémoire ou cette thèse. Ni le mémoire ou la thèse ni des extraits substantiels de ceux-ci ne peuvent être imprimés ou autrement reproduits sans son autorisation.The author retains ownership of the copyright of this dissertation or thesis. Neither the dissertation or thesis, nor substantial extracts from it, may be printed or otherwise reproduced without the author's permission. LISTE DES TABLEAUX Ce modèle reproduit efficacement les signaux transmis par les milieux discontinus, toutefois sa signification physique est incertaine et les conditions hydrodynamiques associées au développement de dimensions non-radiales demeurent énigmatiques. Il en résulte une très faible applicabilité du modèle GRF malgré le très fort potentiel diagnostique renfermé par le paramètre n. On montre que ce paramètre décrit l'évolution géométrique de l'équipotentielle frontale au cours du test hydraulique transitoire. Le comportement non-radial serait donc produit par tout système dont la géométrie -ou les propriétés hydrauliques -produisent une évolution transitoire de cette surface admettant des modifications de forme progressives et régulières. On peut s'attendre à ce que ce phénomène soit engendré par les interactions transitoires entre une faille et sa matrice.Le premier volet de cette thèse se consacre à la vérification de cette hypothèse. La production de comportements non-radiaux n = 1,5 par le discontinuum faille verticale-matrice est démontrée par la modélisation numérique tridimensionnelle aux éléments finis. L'outil numérique a permis de contraindre quantitativement les conditions hydrodynamiques associées à ce comportement.

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Estimation of the sustainable yields of boreholes in fractured rock formations

Cited by 52 publications

References 12 publications

Evaluation of factors influencing transmissivity in fractured hard-rock aquifers of the Limpopo Province

Evaluation of factors influencing transmissivity in fractured hard-rock aquifers of the Limpopo Province

Reliable yields of public water-supply wells in the fractured-rock aquifers of central Maryland, USA

Comportement hydraulique des milieux faillés /

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