The investigation area is located in the world-famous Dinaric karst. This study presents a conceptual model of groundwater dynamics and its interaction with surface waters, extending from the natural ...water retention of the Drežničko Polje to the spring zone on the far side of the Kapela Mountain range, including a description of the regional groundwater flow in the Zagorska Mrežnica spring zone. The aim of this research was to determine the possibility of an artificial enlargement of the natural retention of this karst field. Large amounts of water could be exploited in this way for the existing hydroelectric power plants of Gojak and Lešće on the Donja Dobra River. The prolonged retention of the water wave in the Drežničko Polje would extend its efficiency in regards to the production of electrical energy, and simultaneously achieve the mitigation of floods that frequently occur in the broader area of Ogulin. Photogeological analysis of the area was performed, together with geological and hydrogeological mapping, groundwater tracing, measurements of water flows in streams and springs, exploratory drilling and measurements of water levels in 26 piezometric boreholes in the Drežničko Polje. Available meteorological data from nearby weather stations (Jasenak, Drežnica and Modruš) were exploited, as well as hydrological data collected specifically for the modelling of runoff. Based on the results of the data processing, this study has determined: (1) the dynamics of the groundwater flow from the Drežničko Polje to the spring area of the Zagorska Mrežnica, (2) the dynamics of recharge and discharge of the natural retention of the Drežničko Polje; and (3) an improved interpretation of the Zagorska Mrežnica karst spring dynamics. The obtained results of groundwater flow dynamics indicate typical karst flow conditions in the Dinaric Karst, but also contain some specific features.
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.
Radon is known as the main contributor to natural background radiation exposure and the mapping of different radon phenomenon presents an important task in both a scientific and regulatory context. ...Considering the aspect of radon effects on health, identification of areas with elevated radon levels is a crucial step in radon monitoring and the prevention of adverse effects on the population and the environment. Different needs regarding the monitoring of the environmental radioactivity levels in Europe led to initiatives such as the development of the European Atlas of Natural Radiation (EANR). To present different methods of radon mapping, the European Indoor Radon Map and European Geogenic Radon Map projects are described briefly. The aim of this paper is to present the mapping of different aspects of radon (indoor and geogenic) and its importance in data visualization and information dissemination. The practical experiences worldwide provide context for future activities of radon mapping in Croatia. Existing Croatian initiatives in the field of radon risk research are mostly related to the investigations of indoor radon concentrations and identification of radon prone areas through one national study and several focused studies. A comparison of indoor radon levels in Croatia and several geological parameters identified new areas appropriate for future research that could lead towards a geogenic map of radon potential in Croatia.
Donošenjem Nacionalnog programa provedbe Strategije zbrinjavanja radioaktivnog otpada, iskorištenih izvora i istrošenog nuklearnog goriva, Vlada Republike Hrvatske je ratificirala Strategiju koja ...dijelom određuje gospodarenje reziduima. S obzirom na važeću legislativu bit će nužno regulatorno modificirati trenutačne i predvidjeti buduće rudarske i druge industrijske aktivnosti u kojima nastaju rezidui i pri kojima se manipulira reziduima. U radu se daje detaljan pregled legislative te preporuka i smjernica, u skladu s posljednjim dostignućima, za gospodarenje postojećim i budućim odlagalištima i mjestima za privremeno pohranjivanje rezidua.
By adopting the National Program for the Implementation of the Strategy for the Management of Radioactive Waste, Disused Sources and Spent Nuclear Fuel, the Government of the Republic of Croatia has ratified the Strategy, which partly defines the management of residues. Given the current legislation, it will be necessary to regulate modifications of the current as well as predict future mining and other industrial activities in which residues appear and are manipulated with. This paper gives a detailed review of relevant legislation, and state of the art recommendations and guidelines for the management of existing and future disposal sites and places for temporary storage of residues.
The objective of this research was to prepare a rockfall susceptibility map. Explorations were conducted in the Dubračina River basin (Croatia). The input data included a geological map, an ...orthophoto and a 1-m digital terrain model (DTM). After a talus inventory was prepared, the seed cell concept was applied to define the rockfall source areas. The contributing factors (predictors) of rockfalls were evaluated by the chi-squared test. The analysis confirmed the following predictors: CORINE land cover, lithology, slope, aspect, distance from a spring, distance from a road, distance from a fault, distance from a stream, and distance from the rock-soil geological boundary. A matrix pairwise comparison of the predictor ratings was used to define the most significant contributing factors. The predictors that affected the susceptibility map in the share of 86.3% were the slope (61.6%), lithology (13.4%), CORINE land cover (6.2%), and distance from the rock-soil geological boundary (5.1%). Two susceptibility maps were prepared: one using all nine contributing factors and another using the four most significant factors. The analysis showed that both maps were good, with the same areas under the receiver operating characteristic (ROC) curves. The map prepared with only four contributing factors can be considered a better map due to its more precise spatial definition of critical areas. It can be concluded that geological map, 1-m DTM and orthophoto provide enough data to prepare reliable rockfall susceptibility map. The application of the bivariate statistical zonation method called the “frequency ratio method” was proven to be successful. This research demonstrates that the application of the seed cell concept can be useful to speed up the process of rockfall source area detections in large research regions.
Nitrates present one of the main groundwater contaminants in the world and in the Zagreb aquifer. In order to reduce nitrate concentrations in groundwater, it is necessary to spatially define main ...nitrogen sources and areas which have the highest risk of nitrate contamination. This paper presents a map of nitrate contamination risk in the area of the Zagreb aquifer. It was constructed based on nine different layers that include natural characteristics and anthropogenic pressures. For the construction of the Main map, which has been defined as the most representative one, 15 different variations have been tested. The Main map has shown that the urban part of the City of Zagreb, especially central and eastern parts, together with the area of Jakuševec landfill and marshalling station, present areas with the highest risk of nitrate contamination, which is consistent with the results of previous research.
Groundwater quality is a consequence of cumulative effects of natural and anthropogenic processes occurring in unsaturated and saturated zone, which, in certain conditions, can lead to elevated ...concentrations of chemical substances in groundwater. In this paper, the concept of determining the ambient background value of a chemical substance in groundwater was applied, because the long-term effects of human activity influence the increase in concentrations of substances in the environment. The upper limits of ranges of ambient background values were estimated for targeted chemical substances in four groundwater bodies in the Pannonian region of Croatia, according to the demands of the EU Groundwater Directive. The selected groundwater bodies are typical, according to the aquifer typology, for the Pannonian region of Croatia. Probability plot (PP), the modified Lepeltier method, as well as the simple pre-selection method, were used in this paper, depending on a number of chemical data in analysed data sets and in relation to the proportion of <limit of quantification (LOQ) values in a data set for each groundwater body. Estimates obtained by using PP and the modified Lepeltier method are comparable when data variability is low to moderate, otherwise differences between estimates are notable. These methods should not be used if the proportion of <LOQ values in a data set is higher than 30%; however, the integration of results of both methods can increase the confidence of estimation. If the proportion of <LOQ values is higher than 30%, it is recommended to use the robust pre-selection method with the adequate confidence level. For highly skewed data, the 90th percentile of the pre-selected data set is comparable with other methods and preferable over the 95th percentile. The estimates obtained for inert and mobile substances are comparable on different scales. For highly redox-sensitive substances, estimates may differ by one to two orders of magnitude, in relation to the observed heterogeneity of the aquifer systems. The critical issue in the estimation process is the determination of hydrogeological and geochemical homogeneous units within the heterogeneous aquifer system.
Radioactive waste disposal and management presents a unique problem at the Krško nuclear power plant as it is built and co-owned by the Republic of Croatia and the Republic of Slovenia. Each country ...is responsible for the management of half of the low- and intermediate-level radioactive waste (LILW) and spent nuclear fuel (SNF). So far, Slovenia has officially selected the site for LILW disposal and the Croatian programme has a single location left (since 1999), not officially approved as acceptable. This paper contains a new approach to site selection related to the implementation of GIS technology and presents a map of potential areas for LILW disposal including only the remaining Croatian location. It was constructed based on eleven layers that include natural characteristics and anthropogenic pressures. For the construction of the main map, detailed topological checks and spatial analysis of polygons have been made, reducing potential areas to be further evaluated.
Due to the high vulnerability of the karst aquifer to the surface contaminants, a precisely defined catchment area has the highest priority. In this study, the influence of slope inclination, the ...doline density analysis, and the water budget analysis in the delineation process of a complex karst catchment area is discussed. To define hydrogeological role of lithological units, cross sections of slope inclination and doline density were combined with hydrogeological cross sections, while the degree of karstification was used to describe the permeability of rock units. The verification of karst catchment delineation area was performed with water budget analysis. The methodology used for the determination of hydrogeological behavior and delineation of a complex karst catchment area (Slunjčica River basin, Croatia) is shown with the flow diagram. It has been found that the highest doline density appears in the range from 0 to 1° of the slope inclinations, and that it decreases with a higher slope degree. Although the results of this study confirm that even with the relatively small number of input data it is possible to define the karst catchment area, it must be emphasized that the doline density analysis presents an indispensable tool in the research related to the definition of karst catchment areas.
Radi vrlo visoke prirodne ranjivosti krških vodonosnika, izrazito je važno precizno određivanje slivne površine. U okviru ovog istraživanja razmatran je utjecaj nagiba terena, gustoće vrtača i vodne bilance u procesu razdvajanja složenih krških slivnih područja. Za definiranje hidrogeološke uloge pojedinih litoloških jedinica korištena je kombinacija hidrogeoloških profila s podacima o gustoći vrtača i nagibu terena, dok je za opis propusnosti pojedinih stijenskih jedinica korišten stupanj okšenosti. Za verifikaciju i provjeru izdvojenih slivnih područja korištena je vodna bilanca. Metodologija korištena za utvrđivanje hidrogeološke uloge pojedinog područja i određivanje slivnog područja (rijeka Slunjčica, Hrvatska) prikazana je dijagramom toka. Utvrđeno je da se najveće vrijednosti gustoće vrtača pojavljuju u dijelovima terena s nagibom padina od 0 to 1°, te se smanjuju s povećanjem nagiba padina. Iako rezultati istraživanja potvrđuju da je čak i s malim brojem ulaznih podataka moguće odrediti slivno područje u kršu, potrebno je dodatno naglasiti da analiza gustoće vrtača predstavlja nezamjenjiv alat prilikom istraživanja vezanih za određivanje slivnih područja u kršu.
PDF
