Comparison of Hydraulic Conductivity Values Obtained from Aquifer Pumping Tests and Conservative Tracer Tests

2000 ◽  
Vol 20 (3) ◽  
pp. 122-128 ◽  
Author(s):  
William L. Niemann ◽  
Charles W. Rovey
Keyword(s):  
Hydraulic Conductivity ◽  
Tracer Tests ◽  
Pumping Tests ◽  
Conservative Tracer

scholarly journals Comparison of Two Ensemble-Kalman Filter Based Methods for Estimating Aquifer Parameters from Real 3-D Hydraulic and Tracer Tomographic Tests

Geosciences ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 462
Author(s):  
Emilio Sánchez-León ◽  
Carsten Leven ◽  
Daniel Erdal ◽  
Olaf A. Cirpka
Keyword(s):  
Kalman Filter ◽  
Hydraulic Conductivity ◽  
Ensemble Kalman Filter ◽  
Tracer Tests ◽  
Site Investigation ◽  
Concentration Data ◽  
Arrival Times ◽  
Hydraulic Tomography ◽  
Conservative Tracer ◽  
Observation Wells

Pumping and tracer tests are site-investigation techniques frequently used to determine hydraulic conductivity. Tomographic test layouts, in which multiple tests with different combinations of injection and observation wells are performed, gain a better insight into spatial variability. While hydraulic tomography has repeatedly been applied in the field, tracer tomography lags behind. In a previous publication, we presented a synthetic study to investigate whether the ensemble Kalman Filter (EnKF) or the Kalman Ensemble Generator (KEG) performs better in inverting hydraulic- and tracer-tomographic data. In this work, we develop an experimental method for solute-tracer tomography using fluorescein as a conservative tracer. We performed hydraulic- and tracer-tomographic tests at the Lauswiesen site in Germany. We analyzed transient drawdown and concentration data with the EnKF and steady-state hydraulic heads and mean tracer arrival times with the KEG, obtaining more stable results with the KEG at lower computational costs. The spatial distribution of the estimated hydraulic conductivity field agreed with earlier descriptions of the aquifer at the site. This study narrows the gap between numerical studies and field applications for aquifer characterization at high resolution, showing the potential of combining ensemble-Kalman filter based methods with data collected from hydraulic and solute-tracer tomographic experiments.

scholarly journals Comparison of Two Ensemble Kalman-Based Methods for Estimating Aquifer Parameters from Virtual 2-D Hydraulic and Tracer Tomographic Tests

Geosciences ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 276 ◽  
Author(s):  
Emilio Sánchez-León ◽  
Daniel Erdal ◽  
Carsten Leven ◽  
Olaf A. Cirpka
Keyword(s):  
Hydraulic Conductivity ◽  
Ensemble Kalman Filter ◽  
Tracer Tests ◽  
Tracer Test ◽  
Transient Signal ◽  
Concentration Data ◽  
Pumping Tests ◽  
Test Parameter ◽  
Arrival Times ◽  
Temporal Moments

We compare two ensemble Kalman-based methods to estimate the hydraulic conductivity field of an aquifer from data of hydraulic and tracer tomographic experiments: (i) the Ensemble Kalman Filter (EnKF) and (ii) the Kalman Ensemble Generator (KEG). We generated synthetic drawdown and tracer data by simulating two pumping tests, each followed by a tracer test. Parameter updating with the EnKF is performed using the full transient signal. For hydraulic data, we use the standard update scheme of the EnKF with damping, whereas for concentration data, we apply a restart scheme, in which solute transport is resimulated from time zero to the next measurement time after each parameter update. In the KEG, we iteratively assimilate all observations simultaneously, here inverting steady-state heads and mean tracer arrival times. The inversion with the dampened EnKF worked well for the transient pumping-tests, but less for the tracer tests. The KEG produced similar estimates of hydraulic conductivity but at significantly lower costs. We conclude that parameter estimation in well-defined hydraulic tests can be done very efficiently by iterative ensemble Kalman methods, and ambiguity between state and parameter updates can be completely avoided by assimilating temporal moments of concentration data rather than the time series themselves.

Three-Dimensional Non-Multi-Gaussian Simulation by Including Multiple Types of Information at Non-Colocated Locations

2021 ◽  
Author(s):  
Claus Haslauer ◽  
Bo Xiao ◽  
András Bárdossy ◽  
Olaf Cirpka ◽  
Geoffrey Bohling
Keyword(s):  
Hydraulic Conductivity ◽  
Data Fusion ◽  
Three Dimensional ◽  
Tracer Tests ◽  
Geostatistical Simulation ◽  
Dependence Structure ◽  
Large Set ◽  
Stochastic Hydrogeology ◽  
Spatially Distributed ◽  
Types Of Information

<div> <p><span>The incentive of this presentation is the age-old quest of stochastic hydrogeology: Are we able to better match observed long-tailed breakthrough curves by an improved description of the spatial dependence of saturated hydraulic conductivity (<em>K</em>)?</span></p> </div><div> <p><span> </span></p> </div><div> <p><span>This contribution considers two innovations: We include more information than usual by incorporating multiple types of observations at non-collocated locations (<em>data fusion</em>), and we extract more information than usual from the available measurements by analysing statistical properties that go further than typical second-order moments-based analyses (<em>non-Gaussian geostatistics</em>).</span></p> </div><div> <p><span> </span></p> </div><div> <p><span>The evaluation of these innovations in geostatistical simulation methodologies of spatially distributed fields of <em>K</em> is performed against real-world tracer-tests that were performed at the site of the <em>K</em> measurements. The hypothesis is that fields that contain the most information match the observed solute spreading best.</span></p> </div><div> <p><span> </span></p> </div><div> <p><span>The spatially distributed <em>K</em>- fields were geostatistically simulated using the multi-objective phase annealing (<em>PA</em>) method. To accelerate the asymmetry updating during the PA iterations, a Fourier transform based algorithm is integrated into the three-dimensional PA method. Multiple types of objective functions are included to match the value and/or the order of observations as well as the degree of the “non-Gausianness” (asymmetry). Additionally, “censored measurements” (e.g., high-K measurements above the sensitivity of the device that measures <em>K</em>) are considered.</span></p> </div><div> <p><span> </span></p> </div><div> <p><span>The MAcroDispersion Experiment (MADE) site is considered the holy grail of stochastic hydrogeology as among the well instrumented sites in the world, the variance of the hydraulic conductivity measurements at the MADE site is fairly large and detailed observations of solute spreading are available. In addition to the classic <em>K</em>-measurements obtained via 2611 flowmeter measurements, recently a large set of 31123 <em>K</em>‑measurements obtained via direct push injection logging (DPIL), are available, although not at the same locations where the flowmeter measurements were taken.</span></p> </div><div> <p><span> </span></p> </div><div> <p><span>The influence of including different types of information on the simulated spatially-distributed fields of <em>K</em> are evaluated by analyzing the ensemble spatial moments and the dispersivity of numerical conservative solute tracer tests performed using particle tracking. The improved dependence structure of <em>K</em> with all of the above knowledge contains more information than fields simulated by traditional geostatistical algorithms and expected as a more realistic realization of <em>K</em> at the MADE site and at many other sites where such data-fusion approaches are necessary.</span></p> </div>

scholarly journals Groundwater characteristics at Seabee Hook, Cape Hallett, Antarctica

2006 ◽  
Vol 18 (4) ◽  
pp. 487-495 ◽  
Author(s):  
Erica H. Hofstee ◽  
Dave I. Campbell ◽  
Megan R. Balks ◽  
Jackie Aislabie
Keyword(s):  
Hydraulic Conductivity ◽  
Total Phosphorus ◽  
Ross Sea ◽  
Tracer Tests ◽  
Unconfined Aquifer ◽  
Pygoscelis Adeliae ◽  
Groundwater Velocity ◽  
Melting Snow ◽  
Cemented Soil ◽  
Victoria Land

Seabee Hook is a low lying gravel spit adjacent to Cape Hallett, northern Victoria Land, in the Ross Sea region of Antarctica and hosts an Adélie penguin (Pygoscelis adeliae) rookery. Dipwells were inserted to monitor changes in depth to, and volume of, groundwater and tracer tests were conducted to estimate aquifer hydraulic conductivity and groundwater velocity. During summer (November–February), meltwater forms a shallow, unconfined, aquifer perched on impermeable ice cemented soil. Groundwater extent and volume depends on the amount of snowfall as meltwater is primarily sourced from melting snow drifts. Groundwater velocity through the permeable gravel and sand was up to 7.8 m day−1, and hydraulic conductivities of 4.7 × 10−4 m s−1 to 3.7 × 10−5 m s−1 were measured. The presence of the penguin rookery, and the proximity of the sea, affects groundwater chemistry with elevated concentrations of salts (1205 mg L−1 sodium, 332 mg L−1 potassium) and nutrients (193 mg L−1 nitrate, 833 mg L−1 ammonia, 10 mg L−1 total phosphorus) compared with groundwater sourced away from the rookery, and with other terrestrial waters in Antarctica.

Utilizing time-lapse hydraulic tomography to characterize the subsurface changes during methane and heat injection experiments

2020 ◽  
Author(s):  
Linwei Hu ◽  
Márk Somogyvári ◽  
Sebastian Bauer
Keyword(s):  
Hydraulic Conductivity ◽  
Thermal Water ◽  
Water Injection ◽  
Time Lapse ◽  
Hot Water ◽  
Heterogeneous Structure ◽  
Specific Storage ◽  
Pumping Tests ◽  
Hydraulic Diffusivity ◽  
Hydraulic Tomography

<p>Storage options for the energy storage in the subsurface includes the injection and storage of the “energy gas” (e.g., methane, hydrogen, compressed air) or thermal water into the underground formations. The heterogeneous structure of the storage formations could play a crucial role on the potential storage capacity, as well as the formulation of post treatment strategy. Hence, innovative techniques are required for characterizing the high-resolution formation heterogeneity and monitoring the gas or heat plume distribution in the subsurface after their injections.  Previous studies have shown that flow properties can vary as the gas or thermal water being injected into the aquifer. In this study, we propose a time-lapse hydraulic tomography (HT) method for characterizing the baseline hydraulic information and depicting the hydraulic property changes through a series of cross-well pumping tests. These tests were implemented in two pilot sites for methane and hot water injection tests at Wittstock, Germany. In order to generate a three-dimensional tomographical configuration, each pumping test was conducted at certain depth in a testing well, accompanying with multiple observation points at other wells. Depth-variant pumping and observation segments were formed by the double-packer system. As a result, we achieved 198 and 135 baseline drawdown curves for the methane and heat sites, respectively. For these measured data, we initially evaluated the effective hydraulic conductivity and specific storage of the aquifer according to certain analytical fitting methods. Furthermore, the vertical anisotropy of the hydraulic conductivity was also estimated. Sequentially, the fitted hydraulic parameters and analytical drawdown curves were utilized for correcting the well skin effects on hydraulic traveltimes and attenuations, as they have an unneglectable impact on them.  The corrected hydraulic traveltimes and attenuations were used for the inversion of the baseline hydraulic diffusivity and specific storage, respectively. Hydraulic conductivity distribution was then estimated through these two parameters. After we achieved the baseline information, HT was executed again by repeating the tomographical pumping tests after methane and hot water injections. The same data processing and inversion techniques were applied to the drawdown curves derived from the post-injection period. Inverted hydraulic diffusivity, specific storage, and hydraulic conductivity were compared to the baseline inversion results. Changes on these hydraulic properties could provide the information of the spatial distribution of methane or heat plume.</p>

scholarly journals Using water level and temperature time series to improve hydrogeological parameterization in a complex alluvial system

2019 ◽  
Author(s):  
Luca Vettorello ◽  
Andrea Sottani
Keyword(s):  
Hydraulic Conductivity ◽  
Unconfined Aquifer ◽  
Open Pit ◽  
Homogeneous Distribution ◽  
Groundwater Temperature ◽  
Pumping Tests ◽  
Groundwater Exploitation ◽  
Phreatic Aquifer ◽  
Depth Analysis ◽  
High Level

A new pumping station was designed in the northern high plain of the province of Padua (Veneto region, north-eastern Italy), aiming to reach an overall abstraction rate of about 2 m3/s, in order to relevantly contribute to the regional drinking water supply. Local unconfined aquifer is a highly permeable alluvial system, hydraulically connected to the Brenta river, one of the most important groundwater recharging sources of the entire hydrogeological basin, and the Camazzole lake, a former open-pit mine. This lake deepens below the water table and is directly connected to the surrounding phreatic aquifer and indirectly to the river, forming a 3-element hydraulic equilibrium. In order to evaluate the sustainability of the groundwater exploitation, this case study required an in-depth analysis of the hydrogeological resource, focusing on the estimation of hydraulic conductivity values and distribution. A numerical simulation was needed since the first step of the study, to plan the following field activities and provide a rough representation of the expectable drawdown in the pumped aquifer, even if the initial model had a very high level of uncertainty. Before the pumping tests no experimental data were available, so a homogeneous distribution of hydraulic conductivity was preliminarily assigned to the entire mesh, referring to a single bibliographic value available for the aquifer. After the analytical interpretation of pumping tests, different punctual values of hydraulic conductivity were estimated, but the parameter field was still very difficult to define, due to the complexity of the hydrogeological context and the non-uniqueness of the possible spatial interpolations. The availability of groundwater level observations at a larger scale allowed to calculate a set of hydraulic conductivity fields through the pilot points method, integrating the pumping tests results and extending aquifer characterization to a wider domain. The numerical model was finally calibrated with groundwater temperature monitored trends, reproducing the interaction between the lake and the phreatic aquifer through a heat transport simulation. The resulting hydraulic conductivity distribution has been considerably refined, especially at the interface between the lake and the aquifer, and the parameterization has been further validated using heat as a groundwater tracer.

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