Extending Theis' solution: Using transient pumping tests to estimate parameters of aquifer heterogeneity

2016 ◽  
Vol 52 (8) ◽  
pp. 6156-6170 ◽  
Author(s):  
Alraune Zech ◽  
Sebastian Müller ◽  
Juliane Mai ◽  
Falk Heße ◽  
Sabine Attinger
Keyword(s):  
Aquifer Heterogeneity ◽  
Pumping Tests ◽  
Theis Solution

scholarly journals Technical note: Analytical drawdown solution for steady-state pumping tests in two-dimensional isotropic heterogeneous aquifers

2016 ◽  
Vol 20 (5) ◽  
pp. 1655-1667 ◽  
Author(s):  
Alraune Zech ◽  
Sabine Attinger
Keyword(s):  
Steady State ◽  
Correlation Length ◽  
Heterogeneous Media ◽  
Radial Distance ◽  
Pumping Test ◽  
Two Dimensional ◽  
Aquifer Heterogeneity ◽  
Pumping Tests ◽  
Flow Solution ◽  
Ensemble Mean

Abstract. A new method is presented which allows interpreting steady-state pumping tests in heterogeneous isotropic transmissivity fields. In contrast to mean uniform flow, pumping test drawdowns in heterogeneous media cannot be described by a single effective or equivalent value of hydraulic transmissivity. An effective description of transmissivity is required, being a function of the radial distance to the well and including the parameters of log-transmissivity: mean, variance, and correlation length. Such a model is provided by the upscaling procedure radial coarse graining, which describes the transition of near-well to far-field transmissivity effectively. Based on this approach, an analytical solution for a steady-state pumping test drawdown is deduced. The so-called effective well flow solution is derived for two cases: the ensemble mean of pumping tests and the drawdown within an individual heterogeneous transmissivity field. The analytical form of the solution allows inversely estimating the parameters of aquifer heterogeneity. For comparison with the effective well flow solution, virtual pumping tests are performed and analysed for both cases, the ensemble mean drawdown and pumping tests at individual transmissivity fields. Interpretation of ensemble mean drawdowns showed proof of the upscaling method. The effective well flow solution reproduces the drawdown for two-dimensional pumping tests in heterogeneous media in contrast to Thiem's solution for homogeneous media. Multiple pumping tests conducted at different locations within an individual transmissivity field are analysed, making use of the effective well flow solution to show that all statistical parameters of aquifer heterogeneity can be inferred under field conditions. Thus, the presented method is a promising tool with which to estimate parameters of aquifer heterogeneity, in particular variance and horizontal correlation length of log-transmissivity fields from steady-state pumping test measurements.

Estimating parameters of aquifer heterogeneity using pumping tests – implications for field applications

2015 ◽  
Vol 83 ◽  
pp. 137-147 ◽  
Author(s):  
Alraune Zech ◽  
Sven Arnold ◽  
Christoph Schneider ◽  
Sabine Attinger
Keyword(s):  
Aquifer Heterogeneity ◽  
Pumping Tests

scholarly journals Stochastic analysis of the hydraulic conductivity estimated for a heterogeneous aquifer via numerical modelling

2015 ◽  
Vol 368 ◽  
pp. 472-477
Author(s):  
C. Lu ◽  
Y. Zhang ◽  
L. Shu ◽  
X. Chen ◽  
S. Chen ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Karst Aquifer ◽  
Unconfined Aquifer ◽  
Pumping Tests ◽  
Heterogeneous Aquifer ◽  
The Monte Carlo Method ◽  
The Mean ◽  
Theis Solution ◽  
Observation Wells ◽  
The Impact

Abstract. The paper aims to evaluate the impacts of the average hydraulic conductivity of the heterogeneous aquifer on the estimated hydraulic conductivity using the observations from pumping tests. The results of aquifer tests conducted at a karst aquifer are first introduced. A MODFLOW groundwater flow model was developed to perform numerical pumping tests, and the heterogeneous hydraulic conductivity (K) field was generated using the Monte Carlo method. The K was estimated by the Theis solution for an unconfined aquifer. The effective hydraulic conductivity (Ke) was calculated to represent the hydraulic conductivity of a heterogeneous aquifer. The results of numerical simulations demonstrate that Ke increase with the mean of hydraulic conductivity (EK), and decrease with the coefficient of variation of the hydraulic conductivity (Cv). The impact of spatial variability of K on the estimated Ke at two observation wells with smaller EK is less significant compared to the cases with larger EK.

scholarly journals Technical note: Analytical solution for the mean drawdown of steady state pumping tests in two-dimensional isotropic heterogeneous aquifers

2015 ◽  
Vol 12 (7) ◽  
pp. 6921-6944 ◽  
Author(s):  
A. Zech ◽  
S. Attinger
Keyword(s):  
Steady State ◽  
Analytical Solution ◽  
Correlation Length ◽  
Heterogeneous Media ◽  
Coarse Graining ◽  
Pumping Test ◽  
Two Dimensional ◽  
Aquifer Heterogeneity ◽  
Pumping Tests ◽  
Ensemble Mean

Abstract. A new method is presented which allows to interpret steady state pumping test in heterogeneous isotropic transmissivity fields. In contrast to mean uniform flow, the pumping test drawdowns in heterogeneous media cannot be described by a single effective or equivalent value of hydraulic transmissivity. A radially depending description of transmissivity is required, including the parameters of aquifer heterogeneity: mean, variance and correlation length. Such a model is provided by the upscaling procedure Radial Coarse Graining, which describes the transition of near well to far field transmissivity effectively. Based on the Radial Coarse Graining Transmissivity, an analytical solution for a steady state pumping test drawdown is derived. The so-called effective well flow solution is derived for two cases: the ensemble mean of pumping tests and the drawdown at an individual heterogeneous transmissivity field. The analytical form of the solution allows to inversely estimate the parameters of aquifer heterogeneity from pumping test data. This is shown making use of virtual pumping test data, for both cases the ensemble mean drawdown and pumping tests at individual transmissivity fields. The effective well flow solution reproduces the drawdown for two-dimensional pumping tests in heterogeneous media and is a promising tool to estimate parameters of aquifer heterogeneity, in particular for the horizontal correlation length.

scholarly journals Groundwater level and electrical conductivity datasets acquired within pumping tests on Ilovik Island in Croatia

Data in Brief ◽  
2021 ◽  
pp. 107180
Author(s):  
Josip TERZIĆ ◽  
Marina FILIPOVIĆ ◽  
Ivana BOLJAT ◽  
Ana SELAK ◽  
Jasmina LUKAČ REBERSKI
Keyword(s):  
Electrical Conductivity ◽  
Groundwater Level ◽  
Pumping Tests

scholarly journals Assessing Stream-Aquifer Connectivity in a Coastal California Watershed

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 416
Author(s):  
Bwalya Malama ◽  
Devin Pritchard-Peterson ◽  
John J. Jasbinsek ◽  
Christopher Surfleet
Keyword(s):  
Time Series ◽  
Spectral Analysis ◽  
Water Level ◽  
Time Series Data ◽  
Series Data ◽  
Low Permeability ◽  
Pumping Tests ◽  
Stream Flows ◽  
The Impact

We report the results of field and laboratory investigations of stream-aquifer interactions in a watershed along the California coast to assess the impact of groundwater pumping for irrigation on stream flows. The methods used include subsurface sediment sampling using direct-push drilling, laboratory permeability and particle size analyses of sediment, piezometer installation and instrumentation, stream discharge and stage monitoring, pumping tests for aquifer characterization, resistivity surveys, and long-term passive monitoring of stream stage and groundwater levels. Spectral analysis of long-term water level data was used to assess correlation between stream and groundwater level time series data. The investigations revealed the presence of a thin low permeability silt-clay aquitard unit between the main aquifer and the stream. This suggested a three layer conceptual model of the subsurface comprising unconfined and confined aquifers separated by an aquitard layer. This was broadly confirmed by resistivity surveys and pumping tests, the latter of which indicated the occurrence of leakage across the aquitard. The aquitard was determined to be 2–3 orders of magnitude less permeable than the aquifer, which is indicative of weak stream-aquifer connectivity and was confirmed by spectral analysis of stream-aquifer water level time series. The results illustrate the importance of site-specific investigations and suggest that even in systems where the stream is not in direct hydraulic contact with the producing aquifer, long-term stream depletion can occur due to leakage across low permeability units. This has implications for management of stream flows, groundwater abstraction, and water resources management during prolonged periods of drought.

scholarly journals How to find aquifer statistics utilizing pumping tests? Two field studies using welltestpy

Ground Water ◽  
2021 ◽  
Author(s):  
Sebastian Muller ◽  
Carsten Leven ◽  
Peter Dietrich ◽  
Sabine Attinger ◽  
Alraune Zech
Keyword(s):  
Field Studies ◽  
Pumping Tests
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