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The description of the physical parameters characterizing heat transport in the soil medium, especially on a regional scale, requires long-term and high frequency observations of temperature changes in soil profiles. This paper presents a project for a multi-channel, modular and universal data logger for temperature distribution data collecting in the soil profile, based on open electronic components, such as Arduino microcontroller systems and DS18B20 thermometers. The data logger tests were carried out in two profiles. The seven-month tests did not show any errors in the functioning of the measurement set. The presented device requires an average current of 320 µA, which allows for its stable operation on one battery set for about 300 days in temperate climate conditions. The DS18B20 thermometers allow for accurate and stable temperature measurement (the mean absolute error after laboratory calibration was 0.02°C). The cost of a single measurement-registration device was approximately 76 EUR, representing a competitive price in comparison with commercial data loggers. This allows, with relatively low expenditure, the creation of extensive observation networks for the analysis of the heat flow process in high temporal and spatial resolution. [ABSTRACT FROM AUTHOR]

The presented studies focus on changes in groundwater levels and chemistry, and the identification of important factors influencing these changes on short- and long-term scales in urban areas. The results may be useful for rational and sustainable groundwater planning and management in cities. The studies concerned three aquifers: (1) the shallow Quaternary aquifer, (2) the deep Quaternary aquifer, and (3) the Oligocene aquifer in the capital city of Warsaw (Poland). The spatial variability of groundwater recharge was determined and its changes in time were characterized. The characteristics of groundwater levels were based on long-term monitoring series. The results indicate that urban development has caused overall reduction in infiltration recharge (from 54 to 51 mm/year), which is particularly clear in the city suburbs and in its centre, where land development has significantly densified during the last 30 years. Studies of groundwater levels indicate variable long-term trends. However, for the shallowest aquifer, the trends indicate a gradual decrease of the groundwater levels. In the case of the much deeper Oligocene aquifer, groundwater table rise is observed since the 1970s (averagely c. 20 m), which is related with excessive pumping. Based on the studied results, the groundwater chemistry in the subsurface aquifer indicates strong anthropogenic influence, which is reflected in multi-ionic hydrogeochemical types and the occurrence of chemical tracers typical of human activity. The Oligocene aquifer is characterized by a chemical composition indicating the influence of geogenic factors. [ABSTRACT FROM AUTHOR]

The article presents the results of research on spring mire cupolas of the Wolbórka River, a left tributary of the Pilica River. The sedimentary sequence overlies fluvial sands and includes three series of calcareous tufa separated by peat layers. 14C dating indicates that the sedimentation in the spring mire area began in the late Atlantic (AT) and ended at the end of the Subboreal period (SB2). Analysis of lithological features of the sediments has allowed the reconstruction of environmental conditions and their impact on the functioning of the groundwater outflow zone in the late Holocene. The mutual relationship between the peat layers and successive series of calcareous tufa records the changes in humidity conditions resulting from periodic changes in climatic conditions. The sediments of the spring mire cupolas, which are composed mostly of calcite, also contain gypsum and pyrite. The ratio of gypsum to pyrite has proven to be a useful tool for reconstructing humidity condictions. It has become the basis for demonstrating that calcareous tufas are sediments of dry periods, and the deposition of cupola sediments depended on the hydrodynamic regime and flow rate of the springs. The main factor contributing to the deposition of calcite was the equilibration of the groundwater solution with the partial pressure of carbon dioxide in the atmosphere, at low flow dynamics. [ABSTRACT FROM AUTHOR]

The paper presents spatial analysis and numerical methods to describe the hydrodynamic and hydrochemical conditions in a groundwater system. The research was conducted in the northern part of the Białystok High Plane, eastern Poland, within a Quaternary multi-aquifer system. Spatial analysis was used for imaging the quasi-continuous structure of the system based on a discrete set of hydrogeological data. A high-resolution regional flow model was used to identify the groundwater discharge and discharge zones of the individual aquifers. Calculations have shown a marked asymmetry of the flow system. Deeply incised river valleys in the Niemen River basin more strongly affect the groundwater than the discharge zones in the valleys of the Vistula River basin. As a result, the underground watershed in deeper aquifers is clearly shifted westward in relation to the morphological watershed. The hydrodynamic conditions of the system determined by numerical methods were used to identify the points along the groundwater flow-path for the hydrochemical study. It was the basis for the identification of points located along the groundwater flow direction, which were used in the hydrochemical study. Computational schemes of water solution models were calculated for the quasi-equilibrium state of chemical reactions between the solution and the solid and gaseous phases. Presentation of the chemical reactions allowed determining the origin of changes in the concentrations of individual components dissolved in groundwater. It was found that kaolinitization, i.e. chemical weathering of feldspars and plagioclases is the basic process that most affects the groundwater chemistry. [ABSTRACT FROM AUTHOR]

Studies with application of stable isotopes of oxygen and carbon have been performed on calcareous tufa, groundwater and dissolved inorganic carbon (DIC) from the spring mire cupola in Wardzyń. This study was focused on the verification of the a priori hypothesis that the analysed calcareous tufa is a chemical deposit and on the attempt to supplement an earlier scenario of environmental changes in the Subboreal with oscillations of water temperature. The constructed model of chemical and isotope balance, and δ13C determinations in DIC, allowed for calculating ratios of stable isotopes of carbon in particular speciations and in gaseous CO2. The obtained results coupled with δ13C values in calcite indicate that this mineral precipitated from the solution chemically (without the contribution of living organisms). Additionally, it was possible to reconstruct the temperature range at which the calcareous tufa was formed. The reconstructed scenario of changes in the thermal conditions was refined based on δ18O determinations in groundwater and calcite. Accordingly, the oldest calcareous tufa, with an age of about 5500 cal years BP, was formed in cool climate conditions (with average annual temperatures by about 3 °C lower than presently). The formation of younger series of the calcareous tufa took place between 4400–2900 cal years BP and represents a much warmer period with two distinct cooler episodes at 3900 and 3000 cal years BP, respectively. The course of the obtained temperature curves correlates well with the GISP2 curve and curves obtained for other sites in Northern, and Central Europe. [ABSTRACT FROM AUTHOR]