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Analiza wahań zwierciadła płytkich wód podziemnych na obszarze sandru Brdy

Jaworska-Szulc B., Pruszkowska-Caceres M., Szymkiewicz A., Gumuła-Kawęcka A., Gorczewska-Langner W.

Przegląd Geologiczny

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2017

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Vol. 65, nr 11/1

1069--1074

EN

In the Brda River outwash plain - the largest and the most typical landform of this kind in Poland (Galon, 1972) - there are 10 observation wells of the monitoring network of the Polish Geological Institute - National Research Institute. Analysis ofgroundwater level observations for the period of 2003-2016, obtained from the monitoring network, show a long-term trend of water table lowering. In most cases the groundwater table has been below the monthly average water level since 2006. In order to correlate the water table and weather data from the meteorological station in Chojnice, numerical simulations were performed using HYDRUS1D (Šimůnek et al. 2016) - vadose zone software package, based on the Richards equation. A one-dimensional model of the vadose zone was developed to simulate groundwater recharge, applying different bottom boundary conditions (Constant Pressure Head or Free Drainage) considering bare soil evaporation or root water uptake of the grass cover.

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Application of Monte-Carlo Method to Modelling Influence of Selected Soil Heterogeneity on Macrodispersion of Pollutants in Unsaturated Soil Medium

Gorczewska-Langner W.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2011

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Vol. 15, No 3-4

329-337

EN

The influence of soil heterogeneity on miscible solute transport in soil is analyzed. The transport process is simulated numerically using the Monte-Carlo method. This paper shows how different types of soil heterogeneity influence the process of contaminant spreading. If independent flow paths exist in the soil, the degree of the mixing of pollutants in the outflow from the soil profile is larger. If the preferential flow paths are shorter, the degree of mixing, related to the heterogeneity of the velocity field, is smaller. These effects can be captured using the Monte-Carlo method.

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Wpływ niejednorodności pola prędkości na dyspersję hydrodynamiczną w nienasyconym ośrodku gruntowym: badania eksperymentalne i modelowanie numeryczne

Gorczewska-Langner W.

Biuletyn Państwowego Instytutu Geologicznego

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2010

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nr 442 Hydrogeologia z. 11

43--47

PL

Praca dotyczy zjawiska makrodyspersji, czyli rozprzestrzeniania się substancji rozpuszczonej w wodzie gruntowej w skali makro. Przyczyną makrodyspersji są różnice prędkości w poszczególnych ścieżkach przepływu, które mogą występować nawet w pozornie jednorodnym ośrodku gruntowym. Eksperymenty przeprowadzono na makroskopowo jednorodnych i nienasyconych kolumnach gruntowych o trzech różnych długościach. Zawartość wody w kolumnie mierzono metodą radiometryczną, natomiast koncentrację znacznika – na wypływie z kolumny metodą konduktometryczną. Do opisu transportu masy w kolumnie gruntowej wykorzystano model numeryczny umożliwiający symulację przepływu wody gruntowej szeregiem niezależnych, jak i wzajemnie zależnych ścieżek przepływu.

EN

This work concerns the phenomenon of macrodispersion, i.e. large-scale dispersion effect, caused by the local-scale variability of the flow velocity field, which can exist even in apparently homogeneous natural soils. Experiments were performed on macroscopically homogeneous soil columns of three different lengths with steady-state downward unsaturated flow. The water content in the columns was measured using the radiometric method while the tracer concentration was measured at the outflow using the conductometric method. The numerical model was applied to describe mass transport in the columns. The stochastic model of solute transport based on the assumption that the water flows by paths, with no mass exchange between the adjacent paths, but also it accounts for the possible mass exchange between the paths.

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Application of the Moving Average Method of Simplifying Simulation of Random Fields

Maciejewski S., Gorczewska-Langner W.

Archives of Hydro-Engineering and Environmental Mechanics

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2006

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Vol. 53, nr 2

126-136

EN

A method of simulating random fields using a moving average is proposed in this paper. Random fields were simulated for different sizes of sub-field and different numbers of cycles of calculations of the moving average. For the fields obtained the covariance function was analyzed. In order to estimate the efficiency of the proposed simulation method of random field based on the method of diagonal covariance matrix was performed. It is shown that two of the simulation methods presented are able to generate a multidimensional random variable with required correlation function. However, the method of diagonal covariance matrix has some limitations caused by the size of the simulated random field, which result from the necessity of converting a relatively large matrix. Using the proposed simulation method it is possible to simulate, in a comparatively quick and simple manner, a random field with a large number of nodes on PC-s. The presented method can be useful in the stochastic analysis of transport phenomena in soil.