Hydraulic tomography using joint inversion of head and flux data 

2021 ◽  
Author(s):  
Behzad Pouladiborj ◽  
Olivier Bour ◽  
Niklas Linde ◽  
Laurent Longuevergne
Keyword(s):  
Hydraulic Conductivity ◽  
Joint Inversion ◽  
Data Type ◽  
Data Types ◽  
Hydraulic Tomography ◽  
Flux Data ◽  
Planning And Design ◽  
Constant Rate ◽  
Resolution Analysis ◽  
Constant Head

<p>Hydraulic tomography is a state of the art method for inferring hydraulic conductivity fields using head data. Here, a numerical model is used to simulate a steady-state hydraulic tomography experiment by assuming a Gaussian hydraulic conductivity field (also constant storativity) and generating the head and flux data in different observation points. We employed geostatistical inversion using head and flux data individually and jointly to better understand the relative merits of each data type. For the typical case of a small number of observation points, we find that flux data provide a better resolved hydraulic conductivity field compared to head data when considering data with similar signal-to-noise ratios. In the case of a high number of observation points, we find the estimated fields to be of similar quality regardless of the data type. A resolution analysis for a small number of observations reveals that head data averages over a broader region than flux data, and flux data can better resolve the hydraulic conductivity field than head data. The inversions' performance depends on borehole boundary conditions, with the best performing setting for flux data and head data are constant head and constant rate, respectively. However, the joint inversion results of both data types are insensitive to the borehole boundary type. Considering the same number of observations, the joint inversion of head and flux data does not offer advantages over individual inversions. By increasing the hydraulic conductivity field variance, we find that the resulting increased non-linearity makes it more challenging to recover high-quality estimates of the reference hydraulic conductivity field. Our findings would be useful for future planning and design of hydraulic tomography tests comprising the flux and head data.</p>

scholarly journals Individual and joint inversion of head and flux data by geostatistical hydraulic tomography

2021 ◽  
pp. 103960
Author(s):  
Behzad Pouladi ◽  
Niklas Linde ◽  
Laurent Longuevergne ◽  
Olivier Bour
Keyword(s):  
Joint Inversion ◽  
Hydraulic Tomography ◽  
Flux Data

scholarly journals Transient Hydraulic Tomography Analysis of Fourteen Pumping Tests at a Highly Heterogeneous Multiple Aquifer–Aquitard System

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1864
Author(s):  
Zhanfeng Zhao ◽  
Walter A. Illman ◽  
Yuanyuan Zha ◽  
Tian-Chyi Jim Yeh ◽  
Chin Man Bill Mok ◽  
...  
Keyword(s):  
Additional Data ◽  
Joint Inversion ◽  
Pumping Test ◽  
Observation Data ◽  
Data Types ◽  
Specific Storage ◽  
Pumping Tests ◽  
Hydraulic Tomography ◽  
Low K ◽  
Tomography Analysis

Hydraulic tomography based on geostatistics has proven to be robust in characterizing subsurface heterogeneity in hydraulic conductivity (K) and specific storage (Ss) through the joint inversion of drawdown records from multiple pumping tests. However, the spatially variable estimates can be smooth or even erroneous for areas where pumping/observation data densities are not high. Previous hydraulic tomography surveys conducted at the North Campus Research Site (NCRS) on the University of Waterloo campus in Waterloo, Canada, revealed that the estimated hydraulic parameters were smooth and the known aquitard was erroneously identified as a high K zone. This was likely the consequence of the site being highly heterogeneous, while only utilizing four pumping tests and not having measurable drawdowns in the low K aquitard for inverse modeling. Here, we investigate whether improved K and Ss estimates could be obtained through the inclusion of additional pumping test data by stressing both aquifer and aquitard zones for a sufficiently long period. Specifically, six additional pumping/injection tests were conducted at the site, and a transient hydraulic tomography analysis with 14 tests was completed. Results reveal that there is a significant improvement to the K and Ss tomograms in terms of the visual correspondence with various geologic units, including its connectivity. More importantly, with the availability of additional data, we found that the inverse model now can better capture the high and low K features for nine boreholes when compared with K values obtained from permeameter tests. The estimated K and Ss tomograms are then used for the forward simulation of one additional pumping test not used for model calibration, revealing reasonable predictions. While encouraging results are obtained by including a large number of pumping tests to the transient hydraulic tomography analysis, stratigraphic boundaries are still smoothed, which is a direct consequence of utilizing a geostatistics-based inversion approach that assumes stationarity in statistical properties. To capture such sharp boundaries, incorporation of additional data types, such as geological and geophysical information, may be necessary when data densities are not sufficiently high.

On the use of the ground water fluxes for hydraulic tomography: Theoretical and field-based assessments

2020 ◽  
Author(s):  
Behzad Pouladiborj ◽  
Olivier Bour ◽  
Niklas Linde ◽  
Daniel Paradis ◽  
Jean-Marc Ballard ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Fiber Optic ◽  
Joint Inversion ◽  
Temporal Trends ◽  
Quebec City ◽  
Water Fluxes ◽  
Hydraulic Tomography ◽  
Direct Push ◽  
Groundwater Flux ◽  
Observation Wells

<p>Hydraulic tomography is known for imaging hydraulic conductivity of aquifers. In hydraulic tomography, the aquifer is stressed sequentially at several locations with pumping or slug tests while hydraulic heads are observed in different points. These hydraulic head data along with a numerical model are then used to reconstruct the hydraulic conductivity distribution of the aquifer through inversion process. The reconstructed distribution usually represents smooth-low resolution model of hydraulic conductivity which may be suitable for representation of groundwater flow with limited applicability to transport problems. Here, we investigate the added value of using groundwater fluxes measurement for the reconstruction of hydraulic conductivity in tomographic experiment. Vertical profile of groundwater flux may be estimated using active fiber optic distributed temperature sensor (FO-DTS) methods with FO cables installed by direct push so as it is in direct contact with formation. In active FO-DTS, FO cable is heated and heat is transported by conduction and convection. So different water fluxes result in different temperature behavior. This study is carried out in two parts. First, we conducted a synthetic analyze where we used a sequence of synthetic multivariate Gaussian aquifers with different tomographic configurations and datasets. This analysis showed that joint inversion of groundwater fluxes and hydraulic heads leads to better hydraulic conductivity resolution than using hydraulic heads solely. Inversion of groundwater fluxes alone is also superior than using only hydraulic heads. Then, insights gained from the synthetic study were used to guide the implementation of a field study at the Saint-Lambert experimental site located 40 km south of Quebec City, Canada. The tomography experiment was performed between 3 wells closely spaced (between 5 and 9 m) and two active FO-DTS cables. FO cables were installed vertically by a direct push drilling technique at mid-point between the central pumping well and two observation wells. Discrete intervals along the observation wells were also isolated with packers to monitor temperature and hydraulic heads at different depths in these two screened observational wells. First, the aquifer was constrained to pumping continuously for 24 hours at a constant rate of 10 LPM with simultaneously recording temperature (passive mode) and hydraulic heads in 8 discrete well intervals and in the pumping well itself as well as along the 2 FO-DTS with approximate resolution of 25 cm. Then, by analyzing the piezo-metric heads and making sure that steady-state conditions were achieved, the pumping was held at the same rate but heat was injected to fiber optic cables (active mode) for another 64-hour period. After this period, heating and pumping were stopped. Preliminary results show the feasibility of the active FO-DTS in capturing varying groundwater fluxes with depth, as reflected in the different temporal temperature trend. These temperature trends will be used to estimate the vertical groundwater flux profile from these temperature temporal trends at a vertical resolution of approximately 25 cm. Then estimated fluxes will be used for hydraulic tomography. Those experimental results along with the synthetic analyze are shown to be promising in improving characterization of hydraulic conductivity of aquifers.</p>

Stochastic Modeling of Diffusivity and Constant-Rate Pumping Tests in Heterogeneous Aquifers in a Tomographic Setup and Its Application to Field Measurements

2021 ◽  
Author(s):  
Kan Bun Cheng ◽  
Gedeon Dagan ◽  
Avinoam Rabinovich
Keyword(s):  
Hydraulic Conductivity ◽  
Travel Time ◽  
Field Measurements ◽  
Specific Storage ◽  
First Order ◽  
Hydraulic Tomography ◽  
Constant Rate ◽  
Mean And Variance ◽  
The Mean ◽  
Aquifer Properties

<p>Characterization of spatially variable aquifer properties is a necessary first step towards modeling flow and transport. An emerging technique in hydraulic tomography, known as diffusivity tests, consist of injecting (or pumping) a volume of water through short segments of a well for a short time and measuring the travel time of the peak of the head signal at different points in the surrounding aquifer volume. In our stochastic model, the specific storage is assumed to be constant, while the hydraulic conductivity of the heterogeneous aquifer is modeled as a random lognormal field. The axi-symmetric anisotropic structure is characterized by a few parameters (logconductivity mean and variance and horizontal and vertical integral scales). The mean and variance of the peak travel time are then determined as a function of distance from an instantaneous source by solving the flow equation using a first-order approximation in the logconductivity variance. The mean travel time is recast in terms of the equivalent conductivity, which decreases from the harmonic mean near the source to the effective conductivity in uniform flow for a sufficiently large distance. Similarly, the variance drops from its maximum near the source to a small value.</p><p>A different type of tomographic test is the constant-rate pumping one. We propose to apply the first order stochastic approach to the data from the Boise Hydrogeophysical Research site (BHRS) to characterize the aquifer properties by estimating heterogeneity statistical parameters. Equivalent properties are first calculated by matching a homogeneous aquifer solution to the pointwise data to obtain a spatially varying hydraulic conductivity (K<sub>eq</sub>) and storativity (S<sub>s,eq</sub>). Then the statistical properties of K and S<sub>s</sub> are to be computed by a best fit between the theoretically derived statistical moments of the equivalent random properties (K<sub>eq</sub>, S<sub>s,eq</sub>) and those from field measurements. Our preliminary results indicate that the proposed stochastic methodology is robust and reliable as well as computationally more efficient than the conventional hydraulic tomography techniques.</p>

scholarly journals Hydraulic conductivity field characterization from the joint inversion of hydraulic heads and self-potential data

2014 ◽  
Vol 50 (4) ◽  
pp. 3502-3522 ◽  
Author(s):  
A. Soueid Ahmed ◽  
A. Jardani ◽  
A. Revil ◽  
J. P. Dupont
Keyword(s):  
Hydraulic Conductivity ◽  
Joint Inversion ◽  
Self Potential

scholarly journals Comparison of three measurement methods of saturated hydraulic condutivity

2006 ◽  
Vol 3 (3) ◽  
pp. 987-1019 ◽  
Author(s):  
C. Fallico ◽  
E. Migliari ◽  
S. Troisi
Keyword(s):  
Hydraulic Conductivity ◽  
Measurement Method ◽  
Sandy Loam ◽  
Measurement Methods ◽  
Soil Core ◽  
Statistical Parameters ◽  
Factors Affecting ◽  
Average Value ◽  
Constant Head ◽  
Log Normal

Abstract. After pointing out the importance of the saturated hydraulic conductivity (ks) measurements and the difficulties and uncertainties that are present, and after recalling salient aspects of three well-known measurement methods of this parameter (i.e. constant-head tension infiltrometer (TI) method, constant-head pressure infiltrometer (PI) method and soil core (SC) estimates method), the results of an investigation on data which were obtained during a measurement campaign on an area of 800 m2, on a sandy loam hillslope, located in Southern Italy, were carried out again here. Three sets of values of ks, obtained with these measurement methods, were analyzed statistically, verifying that the log-normal distribution describes these better than the normal one; moreover, the more significant statistical parameters of each set were compared (average value , amplitude A, coefficient of variation CV and standard deviation SD), individualizing the more significant differences. The greatest value of hydraulic conductivity was found with method (PI), while the smallest with (SC) and the intermediate with (TI); these differences were translated into macroporosity and into the influence of the single measurement method. Moreover, referring to the possible factors affecting the results, the importance can be noted of the structure, the texture and the soil events, in terms of utilization, which can affect the measure of ks leading often to very different values even for similar soils, but with a different history, independently of the coincidence of the measurement points and they can be determining to explain the differences affecting the results obtained in analogous investigations by other researchers. Having confirmed that generalization is not possible, the need was emphasized to adopt the necessary devices relating to the specific measurement method, case by case, and to carefully explain the obtained results, in the light of the peculiarities and the limits of each situation. Finally, the results of similar statistical analysis carried out on a greater number of ks values, measured through the (TI) and (PI) methods are shown in this paper, with some statistical considerations on the increasing of the measurements number.

scholarly journals CONTROLE ESTATÍSTICO DE QUALIDADE DA CONDUTIVIDADE HIDRÁULICA EM LUVISSOLO E NEOSSOLO COM VARIAÇÃO DA DENSIDADE DO SOLO

Irriga ◽  
2019 ◽  
Vol 24 (1) ◽  
pp. 16-24
Author(s):  
Floriano Luiz Suszek ◽  
Silvio Cesar Sampaio ◽  
Vera Lucia Antunes De Lima
Keyword(s):  
Hydraulic Conductivity ◽  
Control Charts ◽  
Density Variation ◽  
Statistical Quality Control ◽  
Agricultural Drainage ◽  
Sensitivity Index ◽  
Statistical Control ◽  
Soil Physics ◽  
Constant Head ◽  
Improving Accuracy

CONTROLE ESTATÍSTICO DE QUALIDADE DA CONDUTIVIDADE HIDRÁULICA EM LUVISSOLO E NEOSSOLO COM VARIAÇÃO DA DENSIDADE DO SOLO     FLORIANO LUIZ SUSZEK1; SILVIO CÉSAR SAMPAIO2 E VERA LÚCIA ANTUNES DE LIMA3   1Doutor em Engenharia Agrícola, Programa de Pós-Graduação em Engenharia Agrícola (PGEAGRI), Universidade Estadual do Oeste do Paraná (UNIOESTE), Rua Universitária, nº 1619 – Jd. Universitário, CEP: 85809-110, Cascavel, Paraná, Brasil, [email protected]. 2Universidade Estadual do Oeste do Paraná, Departamento de Recursos Hídricos e Saneamento Ambiental, Rua Universitária, nº 1619 – Jd. Universitário, CEP: 85809-110, Cascavel, Paraná, Brasil, [email protected]. 3Universidade Federal de Campina Grande (UFCG), Centro de Tecnologia e Recursos Naturais, Rua Aprígio Veloso, nº 882, Universitário, CEP: 58429-900, Campina Grande, Paraíba, Brasil, [email protected].     1 RESUMO   A condutividade hidráulica é um dos principais fatores para dimensionamento de sistemas de drenagem agrícola. Uma das metodologias utilizadas para a obtenção da condutividade hidráulica é o permeâmetro de carga constante. Porém a grande variação dos resultados gera necessidade de análises para melhorar a precisão destes, como o uso de gráficos de controle estatístico de qualidade. Este trabalho analisou por meio de gráficos de controle, a metodologia do permeâmetro de carga constante para dois solos diferentes na obtenção da condutividade hidráulica, variando a densidade dos solos e analisando seu índice de sensibilidade. O LUVISSOLO CRÔMICO é mais sensível à variação de densidade do solo, para a condutividade hidráulica, do que o NEOSSOLO REGOLÍTICO. Os gráficos de controle foram úteis na melhoria da precisão dos valores analisados, mostrando a variação da condutividade hidráulica e quais foram os pontos fora dos limites desejáveis.   Palavras-chave: Drenagem agrícola, propriedades físicas do solo, permeâmetro de carga constante.     SUSZEK, F. L.; SAMPAIO, S. C.; LIMA, V. L. A. de STATISTICAL QUALITY CONTROL IN HYDRAULIC CONDUCTIVITY FOR LUVISOL AND ENTISOL WITH DENSITY VARIATION     2 ABSTRACT   Hydraulic conductivity is one of the main factors for the design of agricultural drainage systems. One of the methodologies used to obtain the hydraulic conductivity is the constant head permeameter. However, the large variation of results generates the need for analyzes to improve their accuracy, such as the use of quality statistical control graphs. This work analyzed, by means of control charts, the methodology of constant head permeameter for two different soils in obtaining hydraulic conductivity, varying the density of soils and analyzing their sensitivity index. Luvisol is more sensitive to density variation, for hydraulic conductivity, than  entisol. Control graphs were useful in improving  accuracy of the analyzed values, showing the variation of hydraulic conductivity and what were the points outside the desirable limits.   Keywords: Agricultural drainage, soil physics properties, constant head permeameter.

scholarly journals An approach to identify soil types by using hydraulic conductivity values

2018 ◽  
Vol 2 (1) ◽  
pp. 43-51
Author(s):  
Maritha Nilam Kusuma ◽  
Wahyono Hadi ◽  
Budisantoso Wirjodirdjo ◽  
Yulfiah Yulfiah
Keyword(s):  
Water Treatment ◽  
Hydraulic Conductivity ◽  
Preliminary Analysis ◽  
Soil Types ◽  
Main Role ◽  
Important Indicator ◽  
Pre Treatment ◽  
Constant Head ◽  
Soil Filtration

Water treatment in Indonesia still uses coagulant to reduce the contaminant. Therefore, an infiltration gallery is required as the pre-treatment before conventional water treatment conducted. Infiltration gallery is a natural technology for absorbing or filtrating the contaminant. The hydraulic conductivity plays the main role in soil filtration. There are many types of soil with different hydraulic conductivities. In infiltration gallery method it is important to identify the hydraulic conductivity value as the preliminary analysis because it is the important indicator to show the ability of soil to flow the water from one side to other sides when filtrating the contaminant. The slower the conductivity is, the better the quality of the water will be. The method used in this study was the Constant head Permeameter. The result of this study shows that the same type of soil type has different hydraulic conductivities.

Measuring unsaturated hydraulic conductivity (K(ψm)) of the F and H soil organic layers at small matric potential (ψm)

2011 ◽  
Vol 91 (6) ◽  
pp. 965-968
Author(s):  
B. Wilske ◽  
E. A. Johnson
Keyword(s):  
Hydraulic Conductivity ◽  
Large Data ◽  
Cold Climate ◽  
Organic Layer ◽  
Matric Potential ◽  
Large Variability ◽  
Organic Layers ◽  
Soil Organic Layer ◽  
Unsaturated Hydraulic Conductivity ◽  
Constant Head

Wilske, B. and Johnson, E. A. 2011. Measuring unsaturated hydraulic conductivity (K(ψm)) of the F and H soil organic layers at small matric potential (ψm). Can. J. Soil Sci. 91: 965–968. K(ψm) of the soil organic layers is a key parameter to assess water redistribution in cold-climate forests. This study tested the twin suction disc apparatus (TSD) as a new method to measure K(ψm) of the F and H layers directly. We compared the results to two studies. One represents a large data base, the other used similar sample locations; but both derived K(ψm) from combining two methods, i.e., pressure plate measurements combined with the instantaneous profile technique or the constant head approach. The TSD data are consistent with previous results considering the large variability in K(ψm) from the combined methods. This suggests that the TSD method represents an alternative to determine K(ψm) of the soil organic layer.

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