The physicochemical properties of soil and the unsaturated zone can have a large influence on the infiltration of precipitation into an aquifer. Soil permeability presents soil property that can be very variable. The main objectives of this study were to estimate differences in soil permeability in two dominant types of soils—Fluvisols and Eutric Cambisols—in the area of the Zagreb aquifer and determine the relationship between the physicochemical properties and the permeability of the analyzed soils. For this purpose, the particle size distribution, soil water retention curves (SWRCs), hydraulic parameters, and chemical properties of soils (i.e., electrical conductivity (EC), pH, carbonate content, cation exchange capacity (CEC), and total concentration of zinc (Zn)) from six soil profiles were observed. In general, the results show that Fluvisols have a smaller amount of clay and a higher amount of sand. Furthermore, particle size distribution indicates that Eutric Cambisols have smaller permeability and a slightly higher capacity for retention. In Eutric Cambisols, the percentages of clay, silt, and sand generally do not change with depth. On average, Fluvisols and Eutric Cambisols become impermeable when they reach different values of water content and effective saturation. All results suggest that Fluvisols generally have to desaturate more than Eutric Cambisols to become impermeable. The proportions of sand and Ks increases through the depth of all analyzed soils, while CEC, EC, and Zn decrease. The total Zn generally decrease with depth, which can be attributed to the aerodeposition in the surface horizons of the analyzed soils and their higher availability for binding/sorption elements. Generally, it can be seen that most Zn concentrations increase until 80 cm in depth, after which they decrease. This result indicates that, in these specific locations, the groundwater body is not under the influence of a potentially toxic metal, in this case Zn. Statistical analysis shows a strong correlation between Zn concentrations and some soil properties, such as soil texture and CEC. This may point to the prevalence of Zn retention. Furthermore, statistical results show that silt has a higher influence on the permeability of Eutric Cambisols than Fluvisols.

This article presents results of hydrogeological and hydrogeochemical research conducted at south hills, Ivanščica Mountain, situated in the northwestern part of the Republic of Croatia. Research was carried out in the summer 2013, between July and September. Hydrogeological mapping was undertaken on approximately 20 km 2 (at a scale of 1:25000), with water samples taken from 10 springs. Rocks and deposits were classified into three hydrogeological units with respect to permeability. Two main aquifers were identifiedthe Triassic carbonate aquifer and the Badenian carbonate aquifer. The overall capacity of 41 registered springs (permanent and periodic) was estimated. According to their basic chemical composition, water from springs belong to Ca-HCO 3 (calcium-hydrogen carbonate), CaMg-HCO 3 (calcium magnesium-hydrogen carbonate) and to MgCa-HCO 3 (magnesium calcium-hydrogen carbonate) types.

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Knowing the soil moisture distribution in the unsaturated zone can improve understanding the water flow through the unsaturated zone and thereby enable the calculation of aquifer recharge, which occurs through precipitation. One part of the Zagreb aquifer recharge occurs through infiltration from precipitation. In order to observe and model infiltration from precipitation through the unsaturated zone, the research polygon was constructed at the Velika Gorica well field, located in the southern part of the Zagreb aquifer, Croatia, where hourly measurements of electric conductivity (EC) and soil moisture content were carried out. EC and soil moisture data are measured by Time Domain Reflectometry (TDR) probes which are placed at different depths in the unsaturated zone. Furthermore, electrical resistivity tomography (ERT) measurements were conducted. Geophysical data, along with moisture and EC data from TDR probes, were used as input data for MoisturEC software, in order to obtain soil moisture distribution along a 2D profile. MoisturEC program offers three options for translating EC data to moisture content data which are all tested in this research. We obtained eight moisture content distributions along the observed profile and concluded that MoisturEC provides reasonable results with input data from geophysical measurements and TDR probe measurements. Soil moisture distribution in the unsaturated zone represents the initial conditions for further unsaturated flow modeling. Understanding the flow in the unsaturated zone enables the quantification of effective infiltration and can improve groundwater management.