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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]