MLU: A Windows Application for the Analysis of Aquifer Tests and the Design of Well Fields in Layered Systems

Carlson, Fritz; Randall, Jeff

doi:10.1111/j.1745-6584.2012.00945.x

Cited by 5 publications

(3 citation statements)

References 4 publications

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“…The fourth pumping test was a short term one (4.5 hr), conducted in the studied borehole itself, with no piezometer. Data was analyzed with the MLU software (Carlson & Randall, 2012), which analytically solves drawdown in a multi-layered system. Results from pumping tests, used to validate a posteriori the model, are presented in Section 4.7.…”

Section: Pumping Testsmentioning

confidence: 99%

Earthquakes and Heavy Rainfall Influence on Aquifer Properties: A New Coupled Earth and Barometric Tidal Response Model in a Confined Bi‐Layer Aquifer

Thomas

Fortin

Vittecoq

et al. 2023

Water Resources Research

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Piezometric level response to periodic forcings, like solid earth tide strain, barometric loading or oceanic tide loading, is a useful alternative way to characterize aquifer properties. It was first spread as a tool for aquifer characterization 34 years ago with the model of Hsieh et al. (1987). It was promising in the sense it only needs classical monitoring data (hourly water level) and no expensive field work like a pumping test. Yet its usage is still far from its potential as expressed in the review of McMillan et al. (2019). On the one hand, the pumping test literature, relatively old, covers a wide variety of aquifer geometries and boundary conditions, including, without comprehensiveness, models for confined radial aquifer (Theis, 1935), leaky aquifers (Hantush & Jacob, 1955), double porosity aquifers (Warren & Root, 1963), unconfined aquifer (Neuman, 1972, spatially heterogeneous aquifers with the general radial flow model (Barker, 1988). Research is still ongoing namely on numerical modeling to complexify the possible responses. On the other hand, literature on periodic responses only recently represented a decent variety of aquifer geometry, starting from Roeloffs (1996) and Rojstaczer (1988) for unconfined aquifers, to Wang et al. (2018) for leaky aquifers. Research on this topic now faces the challenge of proposing a comprehensive view and practical guidelines, like did in its time the useful tutorial of Doan et al. (2008). Now the two major and somewhat opposing pitfalls scientists face are the following. The first one is that the existing models are based on strong hypotheses (perfect confinement for Hsieh et al. (1987), negligible storage in the aquitard in Wang et al. (2018),) which of course are not in general met. There is still room for a more general derivation of analytical models, like what Odling et al. (2015) did in the case of the model of Rojstaczer (1988), precising the low frequency behavior which was improperly predicted. The second pitfall, opposing to the first, is that we need to remain as simple as possible, and keep in mind the mathematical limitations of modeling inversion: from n observed variables, we can invert at best n parameters. In that sense, periodic response problems are nearly always over-parametrized, since observations are often limited to phase and amplitude response at one or two frequencies, while hydrodynamic and poroelastic parameters (hydraulic conductivity, storativity, etc.), grow numerous with the complexity of the models. In this paper, we do not claim to give the comprehensive view we

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Section: Pumping Testsmentioning

confidence: 99%

Earthquakes and Heavy Rainfall Influence on Aquifer Properties: A New Coupled Earth and Barometric Tidal Response Model in a Confined Bi‐Layer Aquifer

Thomas

Fortin

Vittecoq

et al. 2023

Water Resources Research

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“…A number of tests were repeated in order to enhance the accuracy of transmissivity estimates. Data from all tests were analyzed using the software package MLU (Carlson and Randall 2012;Hemker 1999), which is based on a three-dimensional analytical solution for transient well flow in layered aquifer systems, whereby transmissivities and resistance values of the hydraulic system are determined via curve fitting. Resistance in this case is defined by the quotient of the saturated thickness and vertical hydraulic conductivity, usually of an aquitard.…”

Section: Aquifer Propertiesmentioning

confidence: 99%

Hydrogeology of an urban weathered basement aquifer in Kampala, Uganda

et al. 2022

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Weathered basement aquifers are vital sources of drinking water in Africa. In order to better understand their role in the urban water balance, in a weathered basement aquifer in Kampala, Uganda, this study installed a transect of monitoring piezometers, carried out spring flow and high-frequency groundwater level monitoring, slug tests and hydrochemical analyses, including stable isotopes and groundwater residence time indicators. Findings showed a typical weathered basement aquifer with a 20–50-m thickness. Groundwater recharge was 3–50 mm/year, occurring during sustained rainfall. Recharge to a deep groundwater system within the saprock was slow and prolonged, while recharge to the springs on the valley slopes was quick and episodic, responding rapidly to precipitation. Springs discharged shallow groundwater, mixed with wastewater infiltrating from onsite sanitation practices and contributions from the deeper aquifer and were characterised by low flow rates (< 0.001 m3/s), low pH (<5), high nitrate values (61–190 mg/L as NO3), and residence times of <30 years. The deeper groundwater system occurred in the saprolite/saprock, had low transmissivity (< 1 × 10−5 m2/s), lower nitrate values (<20 mg/L as NO3), pH 6–6.5 and longer residence times (40–60 years). Confined groundwater conditions in the valleys were created by the presence of clay-rich alluvium and gave rise to artesian conditions where groundwater had lower nitrate concentrations. The findings provide new insights into weathered basement aquifers in the urban tropics and show that small-scale abstractions are more sustainable in the deeper groundwater system in the valleys, where confined conditions are present.

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“…Detailed information on the theoretical background is given by Hemker andMaas (1987) andHemker (1999). Like other analytical methods, MLU assumes simplified aquifer conditions such as homogeneity, isotropy and the infinite horizontal extent of the aquifer (Carlson and Randall, 2012). However, despite making these assumptions MLU allows for analysing more complex aquifer conditions than the other methods applied in this study.…”

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confidence: 99%

Determining hydraulic parameters of a karst aquifer using unique historical data from large-scale dewatering by deep level mining – a case study from South Africa

Schrader¹,

Erasmus²,

Winde³

2014

WSA

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Although karst aquifers constitute some of the most important water resources worldwide, generally accepted methods for reliably characterising their hydraulic properties are still elusive. This paper aims at contributing to the discussion by a first-ever attempt to utilise various sets of unique historical data derived from draining a large dolomitic karst aquifer by deep-level gold mines in South Africa. In contrast to conventional pumping tests which only penetrate thick aquifers to a limited extent from surface, this draining took place at the very bottom of the aquifer offering the rare opportunity to capture its entire thickness of nearly a kilometre. The datasets have been treated as analogies to conventional pumping tests applying various types of analytical methods designed for porous media. In order to increase the robustness of the results and to account for specific local conditions a total of four different analytical methods were applied to calculate (horizontal) transmissivity and storage coefficients. The obtained values, in general, compare favourably to previous studies in the area and values reported in literature for similar aquifer types confirming earlier findings that Darcy-based methods can be successfully applied to karst aquifers if the scale of investigation is large enough. Apart from improving the understanding of local karst hydrology the present study also aimed at retrieving and preserving valuable and unique historical datasets that otherwise would have been lost for scientific evaluation and the proactive preparation for mine closure.

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MLU: A Windows Application for the Analysis of Aquifer Tests and the Design of Well Fields in Layered Systems

Cited by 5 publications

References 4 publications

Earthquakes and Heavy Rainfall Influence on Aquifer Properties: A New Coupled Earth and Barometric Tidal Response Model in a Confined Bi‐Layer Aquifer

Earthquakes and Heavy Rainfall Influence on Aquifer Properties: A New Coupled Earth and Barometric Tidal Response Model in a Confined Bi‐Layer Aquifer

Hydrogeology of an urban weathered basement aquifer in Kampala, Uganda

Determining hydraulic parameters of a karst aquifer using unique historical data from large-scale dewatering by deep level mining – a case study from South Africa

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