Sanja Kapelj

An estimation of groundwater type and origin of the complex karst catchment using hydrological and hydrogeochemical parameters: A case study of the Gacka river springs

Identification of calcite and aragonite is very important for studying different fossil or recent biomineralized skeletons. Problem occurs when scanning electron microscopy is used for studying calcite and aragonite present in the same part of skeleton. The same chemical composition of these two minerals produces the same contrast on SEM images. There are three possible ways how to distinguish calcite and aragonite in such mixture. (1) It is possible to recognize the crystal habits of these two minerals, if the crystal faces are developed.(2) Geochemical difference could be also important tool for distinguishing aragonite (containing large cations like Sr, Ba, or Pb) from calcite (containing small cations like Mg, Mn, Fe, Zn, or Ni). However, it is also possible that large cations remain in calcite crystal structure after phase transformation from aragonite to calcite.(3) Last possibility in distinguishing calcite from aragonite is to use staining methods. There were different staining methods used for SEM analyses with different success. SUZUKI et al. (1993) successfully used Meigen’s staining method, but results provided by Feigl’s staining method were unsatisfactory. Failure of using Feigl’s staining method was caused by erroneous applying of used solutions.

Assessment of aquifer intrinsic vulnerability by the SINTACS method

Application of the SINTACS method for assessment of aquifer intrinsic vulnerability is demonstrated in the catchment areas of Jadro and Žrnovnica springs. Both Jadro and Žrnovnica are the springs of drinking water supplying the population of Split and surrounding settlements. A high-speed economic expansion in the catchment area accompanied with trend of increasing quantity of a number of contaminants in the spring water prompted comprehensive investigations with purpose of finalizing the Water Management Study of the Jadro and Žrnovnica springs. Results of the Study were treated by GIS tools and employed as input data for making the groundwater vulnerability map of the Jadro and Žrnovnica catchment areas. In addition to the standard method of defining the C factor which, in this case, is represented by the values of C(a), a modification is also introduced which takes into account the analysis of the sinkhole density.

Hydrogeological Conditions and the Necessity for Sanitary Protection of the Norinska River - Prud Spring, Metkovic, Croatia

A detailed description of the hydrogeological relationships in karst aquifers from this part of the Dinarides, together with the recommended conditions for their protection are given. The Norinska river spring is recharged by groundwater flow from the northwest, mainly from the Jezerac polje region, the northern part of Rastok polje and the middle course of the Trebizat river. On the basis of geological, hydrogeological, hydrological and hydrogeochemical studies, it was determined that part of the water is lost to the subsurface in the region between the Ljubusko polje and the Kravice waterfall and is later discharged at the Norinska river spring. Due to the presence of sulphate, the chemical composition of waters from springs along the Trebizat river basin (and its headwaters), is similar to waters from the Norinska river spring. The sulphate in some springs along the north and north-east valley side of the Tihaljina river is the principal anion, and since these waters contribute to the waters in the Norinska river catchment they also affect its water chemistry. Turbidity and the occurrence of fine sand at the Norinska river spring confirms the existence of developed underground channels, conduits and siphons, along which groundwater flows at velocities greater than 5 cm/s during high pluvial periods. The origin of the sulphate is attributed to the presence of gypsum and anhydrite deposits in the deeper parts of the karstic aquifer. The groundwater protection zones were determined on the basis of the groundwater flow velocities, groundwater retention, urban development and the types of industries present within the areas covered by the Ljubuski and Vrgorac municipalities. Presented map is the basis for micro-zoning and the determination of locations for future mercantile (industrial) facilities. The study was focused towards surface karst phenomena and their protection from anthropogenic influence.

Assessment of Groundwater Vulnerability in Croatian Karstic Aquifer in Jadro and Žrnovnica Springs Catchment Area

The groundwater vulnerability assessment is based on the evaluation of physical, chemical, and biological properties of the environment which can provide a certain degree of protection to the groundwater from contamination. In this paper are presented results of application four different methods (SINTACS, EPIK, PI, and COP) for groundwater vulnerability assessment in karstic aquifer in Croatia. The main objectives of the study were to apply the methods on test site where, so far, groundwater vulnerability was never assessed, then to modify the methods in order to improve adaptation to the research field and available data. After comparing vulnerability maps obtained by all four presented methods, it was determined that the most appropriate method is COP + K, which was additionally modified. Although presented methodology is not new, it can be used as a background for land-use planning, because it identifies parts of the catchment area that are, due to its natural features, more vulnerable to human impact. It can be also applied as an additional tool in groundwater protection for delineation of protection zones, and provides very useful data in various fields of water management, especially for karst area in Croatia.

Stručni rad Analiza opasnosti od onečišćenja podzemnih voda u kršu na primjeru sliva izvora Jadro i Žrnovnica

The catchment area of the Jadro and Žrnovnica springs, which is a typical Dinaric karst aquifer that supplies water to the city of Split and its surroundings, is studied in the paper. The trend of typical spring-water pollution indicators is analysed, water quality is estimated, and anthropogenic impact is assessed based on the COST 620 procedure, through analysis of hazards threatening to pollute water in this drainage area.