scholarly journals Inferring geostatistical properties of hydraulic conductivity fields from saline tracer tests and equivalent electrical conductivity time-series

2020 ◽  
Vol 146 ◽  
pp. 103758
Author(s):  
Alejandro Fernandez Visentini ◽  
Niklas Linde ◽  
Tanguy Le Borgne ◽  
Marco Dentz
Soil Research ◽  
2013 ◽  
Vol 51 (1) ◽  
pp. 23 ◽  
Author(s):  
Mohammad Reza Neyshabouri ◽  
Mehdi Rahmati ◽  
Claude Doussan ◽  
Boshra Behroozinezhad

Unsaturated soil hydraulic conductivity K is a fundamental transfer property of soil but its measurement is costly, difficult, and time-consuming due to its large variations with water content (θ) or matric potential (h). Recently, C. Doussan and S. Ruy proposed a method/model using measurements of the electrical conductivity of soil core samples to predict K(h). This method requires the measurement or the setting of a range of matric potentials h in the core samples—a possible lengthy process requiring specialised devices. To avoid h estimation, we propose to simplify that method by introducing the particle-size distribution (PSD) of the soil as a proxy for soil pore diameters and matric potentials, with the Arya and Paris (AP) model. Tests of this simplified model (SM) with laboratory data on a broad range of soils and using the AP model with available, previously defined parameters showed that the accuracy was lower for the SM than for the original model (DR) in predicting K (RMSE of logK = 1.10 for SM v. 0.30 for DR; K in m s–1). However, accuracy was increased for SM when considering coarse- and medium-textured soils only (RMSE of logK = 0.61 for SM v. 0.26 for DR). Further tests with 51 soils from the UNSODA database and our own measurements, with estimated electrical properties, confirmed good agreement of the SM for coarse–medium-textured soils (<35–40% clay). For these textures, the SM also performed well compared with the van Genuchten–Mualem model. Error analysis of SM results and fitting of the AP parameter showed that most of the error for fine-textured soils came from poorer adequacy of the AP model’s previously defined parameters for defining the water retention curve, whereas this was much less so for coarse-textured soils. The SM, using readily accessible soil data, could be a relatively straightforward way to estimate, in situ or in the laboratory, K(h) for coarse–medium-textured soils. This requires, however, a prior check of the predictive efficacy of the AP model for the specific soil investigated, in particular for fine-textured/structured soils and when using previously defined AP parameters.


Soil Research ◽  
2008 ◽  
Vol 46 (1) ◽  
pp. 37 ◽  
Author(s):  
M. R. Sargeant ◽  
C. Tang ◽  
P. W. G. Sale

Landholder observations indicate that the growth of Distichlis spicata in saline discharge sites improves the soil condition. An extensive soil sampling survey was conducted at the Wickepin field site in Western Australia, where D. spicata had been growing for 8 years, to test the hypothesis that this halophytic grass will make improvements in chemical and physical properties of the soil. Soil measurements included saturated hydraulic conductivity, water-stable aggregates, root length and dry weight, electrical conductivity, pH, and soil nitrogen and carbon. Results confirm that marked differences in soil properties occurred under D. spicata. For example, a 12-fold increase in saturated hydraulic conductivity occurred where D. spicata had been growing for 8 years, compared to adjacent control soil where no grass had been growing. There were also improvements in aggregate stability, with the most notable improvements in the top 0.10 m of soil, again with the greatest improvements occurring where 8 years of growth had occurred. Soil nitrogen and carbon increased under the sward, with the biggest increases occurring in the top 0.10 m of soil. Electrical conductivity measurements were more variable, mostly due to the large spatial and temporal variation encountered. However, the findings generally support the proposition that the growth of D. spicata does not lead to an accumulation of salt within the rooting zone.


Soil Research ◽  
1981 ◽  
Vol 19 (3) ◽  
pp. 361 ◽  
Author(s):  
D Subhashini ◽  
BD Kaushik

Algal growth resulted in significant reductions in pH, electrical conductivity, exchangeable sodium and in hydraulic conductivity and aggregation status of the soil. There was a significant increase in the total nitrogen content of the soil due to algal growth. Two out of the three inoculated species of algae could establish in the pots along with the indigenous algal flora. Combination of gypsum and algal application were found to have appreciable reclamative properties, and the possibility of using algae as a biological input for the reclamation of sodic soils has been indicated.


2015 ◽  
Vol 31 (6) ◽  
pp. 45-58
Author(s):  
Jinwook Kim ◽  
Hyunwook Choo ◽  
Changho Lee ◽  
Woojin Lee

2019 ◽  
Vol 112 (1) ◽  
pp. 50-61 ◽  
Author(s):  
Katharina Gröbner ◽  
Wolfgang Gadermayr ◽  
Giorgio Höfer-Öllinger ◽  
Harald Huemer ◽  
Christoph Spötl

AbstractThe Leoganger Steinberge are a heavily karstified massif largely composed of Dachstein dolomite and limestone hosting the deepest through-trip cave in the world, Lamprechtsofen, whose frontal parts are developed as a show cave. Many parts of this 60 km-long and 1724 m-deep system are hydrologically active. 1.5 km behind the lower cave entrance Grüntopf stream and Kneippklamm stream merge to form the main cave stream. Another underground stream, Stainerhallen stream, flows through the eponymous hall of the show cave. Since 2007 water temperature, electrical conductivity and water level have been monitored in the Grüntopf and Kneippklamm stream. Water temperature and water level in the Stainerhallen and main cave stream have been measured since 2016.The long-term dataset (2013–2017) shows that the water temperature of the cave streams (Grüntopf stream: 3.7–5.2°C; Kneippklamm stream: 5.1–5.9°C) is largely invariant, but the electrical conductivity varies strongly (Grüntopf stream: 107–210 µS/cm; Kneippklamm stream: 131–248 µS/cm) in response to snowmelt and precipitation events. The event water of the Kneippklamm stream is characterized by a low electrical conductivity and is then followed by slightly warmer and higher mineralized water derived from the phreatic zone. This dual flow pattern also explains the asymmetrical changes of the water level during snowmelt: the fast event water flows directly through vadose pathways to the measurement site, whereas the hydraulic (phreatic) response is delayed. The Grüntopf stream reacts to precipitation and snowmelt events by changes in the karst-water table, which can be explained by a piston flow-model. The Kneippklamm stream reveals evidence of a lifter system.The altitude of the catchments was calculated using δ18O values of water samples from the underground streams and from surface precipitation. The Grüntopf stream shows the highest mean catchment (2280 m a.s.l.), which is in agreement with its daily fluctuations of the water level until August caused by long-lasting snowmelt. The Stainerhallen stream has the lowest catchment (average 1400 m a.s.l.). The catchments of the other two streams are at intermediate elevations (1770–1920 m a.s.l.). The integration of the catchment analyses and observations from tracer tests conducted in the 1970s showed that the latter reflected only one aspect of the karst water regime in this massif. During times of high recharge the water level rises, new flow paths are activated and the karst watershed shifts.


1969 ◽  
Vol 41 (1) ◽  
pp. 25-34
Author(s):  
Juan A. Bonnet ◽  
Eduardo J. Brenes

1. The area of soils surveyed in Lajas Valley was 24,656 acres. 2. The soils were classified into normal, saline, saline-alkali, and non- saline-alkali at depths of 0 to 8, 8 to 24, 24 to 48, and 48 to 72 inches, respectively. 3. A large percentage of normal soils was found in the upper soil layer and of saline-alkali soils in the lower layers. 4. Normal soils occupied about 86 percent of the surface area to a depth of 8 inches and about 63 percent at a depth of 8 to 24 inches. 5. Soils with a salinity problem increased from 9 percent at a depth of 8 inches to 28.3, 58.8 and 68.5 percent, respectively, at depths of 8 to 24, 24 to 48, and 48 to 72 inches. 6. The soils with a salinity problem were largely of the saline-alkali class. 7. In four soil-profile samples taken from Lajas Valley, the saturation percentage varied from 58 to 191, the electrical conductivity from 0.8 to 28.4 millimhos per centimeter, the exchangeable-sodium percentage from 2.2 to 46.0, the soil pH from 8.1 to 8.9, the content of gypsum from 0 to 21.9 tons per acre-foot, the gypsum requirement from 0 to 23.8 tons per acre-foot, and the hydraulic conductivity from less than 0.005 to 6.24 inches of water per hour. Higher gypsum contents were found in the deep subsoil layers of two soils (profiles 1 and 4). Amounts of gypsum varying from 9.9 to 20.3 tons per acre-foot of depth, are required for the reclamation of the surface layers of these two profiles. In general, the hydraulic- conductivity values show that the soil-surface layers are more permeable than the subsoil layers. 8. The procedure and methods used in this paper were found to be accurate, simple, rapid, and practical. They are recommended for the coordination of data related to the classification and reclamation of soils affected by salinity problems in the different countries of the world.


2020 ◽  
Vol 24 (4) ◽  
pp. 1823-1830 ◽  
Author(s):  
José Manuel Tunqui Neira ◽  
Vazken Andréassian ◽  
Gaëlle Tallec ◽  
Jean-Marie Mouchel

Abstract. This technical note deals with the mathematical representation of concentration–discharge relationships. We propose a two-sided affine power scaling relationship (2S-APS) as an alternative to the classic one-sided power scaling relationship (commonly known as “power law”). We also discuss the identification of the parameters of the proposed relationship, using an appropriate numerical criterion. The application of 2S-APS to the high-frequency chemical time series of the Orgeval-ORACLE observatory is presented here (in calibration and validation mode): it yields better results for several solutes and for electrical conductivity in comparison with the power law relationship.


2006 ◽  
Vol 38 (02) ◽  
pp. 451-464 ◽  
Author(s):  
T. J. Kozubowski ◽  
M. M. Meerschaert ◽  
K. Podgórski

Fractional Laplace motion is obtained by subordinating fractional Brownian motion to a gamma process. Used recently to model hydraulic conductivity fields in geophysics, it might also prove useful in modeling financial time series. Its one-dimensional distributions are scale mixtures of normal laws, where the stochastic variance has the generalized gamma distribution. These one-dimensional distributions are more peaked at the mode than is a Gaussian distribution, and their tails are heavier. In this paper we derive the basic properties of the process, including a new property called stochastic self-similarity. We also study the corresponding fractional Laplace noise, which may exhibit long-range dependence. Finally, we discuss practical methods for simulation.


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