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This paper presents a qualitative approach for assessing land-use pressures on the water resources of a transboundary Dinaric karst catchment of the Kupa River in Southeast Europe. Spatial analyses of the water quality indices for surface water and groundwater were carried out in a GIS environment, as well as a detailed assessment of man-made hazards based on recommendations of COST Action 620. The produced maps provide an insight into the qualitative status of water resources at a regional scale by indicating areas of potential negative impacts of land use through the identification of point and diffuse sources of pollution. Higher values of the water quality indices for surface water and groundwater are observed in lowland areas, karst plateaus and poljes, where the impacts of anthropogenic activities such as agriculture and quarries take place on karstified permeable carbonate rocks. Hazard assessment showed how transport infrastructure induces a low hazard level. Settlement areas without proper sewerage systems impose moderate hazard levels, while direct wastewater discharges into groundwater and waste illegally disposed in karst swallow holes and caves located near settlements were classified as having high hazard levels. The applied methods proved to be suitable even in challenging karst environments where the complex properties and structure make the exploration and monitoring of groundwater resources difficult and scarce.

Otok Vis jedan je od rijetkih hrvatskih otoka koji javnu vodoopskrbu osigurava isključivo iz vlastitog vodonosnika. Najvažniji su vodoopskrbni objekti centralno smješteno crpilište Korita s pet radnih bušenih zdenaca, kaptirani izvor Pizdica i bušeni zdenac Brojkovica iznad Komiže. Infiltracija, nakupljanje i istjecanje podzemnih voda odvijaju se u okršenoj stijenskoj masi, a hidrogeološki odnosi uvjetovani su geološkom građom terena. Najvažniji je utjecaj dviju hidrogeoloških barijera – vulkanogeno-sedimentno-evaporitnog kompleksa komiškog zaljeva zapadno od vodonosnika i krških polja južno od njega. U radu je prikazan pregled hidrogeoloških istraživanja na otoku Visu tijekom povijesti, te srodnih istraživanja bez kojih se hidrogeološka ne bi mogla provoditi. Prikazat će se geološka istraživanja, kao najvažnija podloga, te hidrogeološka istraživanja različitim metodama: kartiranja u različitim mjerilima, strukturnogeološke analize, izračuni hidrauličkih parametara vodonosnika, trasiranje podzemnih tokova, hidrokemijska istraživanja i analize trendova, razina, temperatura i elektrolitičke vodljivosti podzemne vode. U nepovoljnom klimatskom scenariju vjerojatno bi se na otoku moralo (1) povećati crpne količine i dodatno snižavati razine podzemne vode na vodocrpilištima, (2) izraditi dodatne zdence izvan neposrednog područja utjecaja trenutnih crpilišta, (3) desalinizirati blago bočatu vodu ili (4) razmotriti mogućnosti umjetnog napajanja vodonosnika. Svaka opcija zahtijeva hidrogeološka istraživanja, uz primjenu novijih metoda te kontinuiran monitoring više parametara uz razrađen sustav ranog upozoravanja i intervencije. Iako je otok Vis, s hidrogeološkog aspekta, najistraživaniji otok u Hrvatskoj (pogotovo od 1950.-ih do 1980.-ih godina, zbog boravka mornarice tadašnje države), postoje potrebe za brojnim dodatnim istraživanjima, prvenstveno novim pristupima, opremom i metodama kojima prethodni istraživači nisu raspolagali.

The technological advancement of analytical techniques and laboratory instruments brought to light a wide spectrum of anthropogenic substances referred to as “Emerging Contaminants” (EC). EC encompass pharmaceuticals and personal care products (PPCP), industrial, agricultural, and lifestyle compounds, as well as their metabolites. This vast group of existing and newly synthesized contaminants enters the water environment mainly through wastewater effluents and is found in relatively low concentrations (ng/I to μg/I) in surface water and groundwater. The EC's transport, fate, persistency, and ecotoxicological effects are still largely uncharted, despite the recent increase in their research. The majority of these substances are not part of existing legislation and consequently are not included in routine surface water/groundwater monitoring activities, thus posing a potential threat to human health and ecosystems as a whole. Karst water resources supply nearly 25% of the world's population with drinking water (Ford & Williams, 2007) and are characterized with particular heterogeneity and anisotropy of structural and hydraulic features. However, specific and complex hydrogeological properties make karst aquifers particularly vulnerable to contamination, while their investigation is quite challenging. The occurrence of various EC compounds in the karst water environment is unraveled through many recent studies. This study is focused on a typical Dinaric karstic catchment of Jadro and Žrnovnica springs (250-500 km2), which supplies water to the city of Split and its wider surroundings. Hydrogeological field investigation is being conducted on spring, surface, and groundwater for analyses of EC, major ions and stable isotopes, including in situ measurements of main physio- chemical parameters. The aim is to identify the main EC from the group of PPCP, their behavior and fate through transport and hydrological modeling, but also to gain insights into the complex hydrogeological properties of this karstic catchment.

In the EU Drinking Water Directive (EU DWD) 2020/2184, the approach of “water safety plan” as suggested by the WHO, has been individuated as the correct tool for water utilities to ensure safe drinkable water. The ADRION Interreg project MUHA moved from the necessity to effectively link different aspects of the water related risks management in an improved response system, integrating functions of analysis, forecasting and incident command systems. This paper aims at describing the rationale of the MUHA project and presenting some of the main outcomes.

Prirodne katastrofe i katastrofe uzrokovane čovjekovom djelatnošću predstavljaju sve veću prijetnju u vodoopskrbi stanovništva pitkom vodom. Opasnosti poput suša, poplava, slučajnih onečišćenja i potresa najveći su rizici sigurne vodoopskrbe, za čiju je obranu potrebno definirati usklađene mehanizme i protokole nadležnih institucija. Iz tog razloga su u izmjenama i dopunama Zakona o vodi za ljudsku potrošnju iz 2017. godine (NN 104/17) planovi sigurnosti voda definirani kao bitan element upravljanja opasnostima i mogućim rizicima te su prema europskoj Direktivi o vodi ispravan alat za sigurnu vodoopskrbu pitkom vodom. Glavni ciljevi projekta MUHA, sufinanciranog iz programa INTERREG ADRION su izrada harmoniziranoga plana, metoda i definiranih naredbi provedbe, kao odgovarajućih mehanizama u slučaju opasnsoti s ciljem poboljšanja planova sigurnosti voda. Upravo će tako, jedan od glavnih alata projekta MUHA WASSP- DSS pomoći u identificiranju i procjeni rizika mogućih opasnih događaja koji utječu na vodoopskrbni sustav. Unaprjeđenje alata biti će moguće kroz konstituirajuću mrežu UNAS, koja korisnicima pruža jednostavnu, učinkovitu i sigurnu transnacionalnu platformu za razmjenu znanja i iskustava o MUHA alatu i daje smjernice za izradu poboljšanih planova sigurnosti voda. Navedeni rezultati pomoći će u izradi dokumenta strateškog usmjeravanja za uspješniju provedbu planova sigurnosti voda. Uz navedene projektne rezultate, Hrvatski geološki institut provodi hidrogeološko istraživanje u zadarskom zaleđu na prostoru slijeva Bokanjac – Poličnik, s naglaskom na slijev krškog izvora Golubinka.

The Golubinka spring is a typical coastal karst spring. It is situated in Northern Dalmatia, Croatia. The groundwater springs through the cave system, while most of the catchment area is built of karstified limestones. Geophysical research ; electrical tomography profiles have been done to improve understanding of the springs’ nearby outflow system. In the paper, these findings have been compared with hydrochemical circumstances and previous conceptual models, and they pointed out a few relevant facts. There are several karst conduit systems at the end of the catchment, connected or not with the previously explored cave systems. A conceptual model was improved based on the detailed hydrogeological map of the spring’s second sanitary protection zone and new findings obtained by electrical resistivity tomography. The research was conducted within the Interreg Adrion project MUHA (Multihazard framework for water-related risks management) because it was the project’s pilot area in Croatia. The explorations' main goal was to better understand hydrogeological circumstances in this very complex Dinaric karst system. The spring is coastal, and seawater penetration into its aquifer happens periodically. The spring is also a public water supply extraction site, and its protection significantly depends on the geological structure and rock mass karstification. MUHA project targets several types of hazards and risks that affect potable water resources and water-related issues (accidental pollution, flooding, drought, and failure of critical infrastructure due to earthquakes). Seawater influence on the Golubinka spring water is highly connected with drought events and pumping for water supply. These main hazards decrease groundwater pressure in the karst aquifer and allow seawater intrusions. Conceptual modeling and a better understanding of the spring’s nearby hinterland can lead to engineering solutions, such as corrections of the pumping regime and/or relocating the extraction site in the future.

Plan sigurnosti voda za ljudsku potrošnju podrazumijeva definiranje rizika, procjenu utjecaja hazarda te preventivno upravljanje rizicima i krizama kojima se osigurava najučinkovitija sigurna opskrba vodom. U široj regiji prilikom definiranja rizičnog područja dodatnu otežavajuću okolnost čine prekogranični vodonosnici. Prema UNECE (2009b) čak 40 % površine vodoopskrbnih sljevova u Europi ima prekogranični karakter.. Kako bi se osigurao efikasno i učinkovito suzbijanje hazarda i kriza potrebno je definirati usklađene mehanizme i protokole svih upravljačkih jedinica koje djeluju na području jednog vodonosnika. U travnju 2020. godine kao odgovor na postavljene izazove uspostavljen je projekt MUHA (eng. Multihazard framework for water related risks management) kojim će se predložiti usklađenje svih protokola na razini Jadransko jonske regije.

Ovim je dokumentom učinjen prvi korak u definiranju geološke, biološke i speleološke podloge izrađene u svrhu buduće prijave područja Imotske krajine za Global Geoparks UNESCO. Priručnik sadrži opći geološki prikaz, regionalne hidrogeološke odnose i hidrogeološke značajke te biološke i speleološke karakteristike geoparka Imotska jezera. Opisano je 10 geoloških točaka/područja: Modro jezero, Crveno jezero, sustav Suvaja-Vrljika (Opačac i Jauk)-Perinuša- Matica, kanjon Badnjevice, Ričice, prijevoj Drežanj-Sridnje brdo, jezero Galipovac, Mamića jezero, Knezovića jezero, Prološko blato, spilja Zovnjača i izvor Krčevac.

The technological development of laboratory instruments and analytical methods combined with the use of innovative approaches bring out a spectrum of new questions and challenges regarding the occurrence of recently unknown or unmonitored anthropogenic sources of aquatic environment’s contamination, so-called “Emerging Contaminants” (EC). The majority of these substances, such as a wide range of pharmaceuticals and personal care products (PPCP) find their way into the soil and water through excretion, waste disposal and wastewater, where they are usually present in low concentrations (ng/I to μg/I). Given the lack of knowledge on their ecotoxicity, persistence, transport and fate, EC are not included in regular surface water/groundwater monitoring on EU level, which represents a problem of cross-border concern and should be tackled by strong transnational cooperation of renowned experts and relevant stakeholders. This is where Interreg Central Europe project boDEREC-CE (Board for Detection and Assessment of Pharmaceutical Drug Residues in Drinking Water – Capacity Building for Water Management in Central Europe) steps in, by focusing on the design of an integrated management of waterworks and recommendations for the improvement of existing legislation on drinking and wastewater standards as well as technical solutions. As a project’s starting point, a review of state-of-the-art of current practices in relation to EC in the water environment will help to identify relevant types of substances, existing analytical and monitoring techniques, attenuation strategies and approaches on national and transnational level. Afterwards, in eight preselected pilot areas across Central Europe grouped in three clusters (groundwater extraction sites, surface water extraction sites, extraction sites in karstic areas), representing different hydrological systems under various environmental pressures, behaviour of EC, characteristics of the natural attenuation and removal efficacy of different treatment techniques will be thoroughly studied via jointly developed monitoring methodology and common project EC database. Building upon the results of previous successful EU projects, in particular FREEWAT, NORMAN, MARS and GLOBAQUA, boDEREC-CE partners will develop an implementation strategy of a model-based decision making process for EC called “modePROCON”, which will be continuously tested and evaluated during stakeholder capacity building workshops. Another main project output will be “wwDEMAST”, a framework for decision- making support tool used by waterworks, for selecting the optimal EC treatment method. In order to foster future cooperation and dissemination of boDEREC-CE results on EU level, a Board of experts will be established. boDEREC-CE project is co-financed under the Interreg Central Europe Programme 2014-2020 priority specific objective „3.1. To improve integrated environmental management capacities for the protection and sustainable use of natural heritage and resources“. The project worth € 2.328.140, 81, started its 3-year implementation in April 2019 and will gather 12 project partners originating from 7 EU countries (Austria, Czech Republic, Croatia, Germany, Italy, Poland and Slovenia). The Department of Hydrogeology and Engineering Geology of Croatian Geological Survey (HGI-CGS) has in boDEREC-CE project a role of Lead Partner with selected pilot area “Jadro and Žrnovnica springs catchment”. Within that pilot, certain particularities of EC occurrence, transport, and behaviour in karst aquifers will be studied, as well. Since Jadro and Žrnovnica catchment is a typical Dinaric karst terrain, autopurfication is quite poor, and interaction of groundwater sampled on springs and in boreholes with surface water of Cetina River will be compared. Given how HGI-CGS also participates in international Horizon 2020 project GeoTwinn (Strengthening research in the Croatian Geological Survey: Geoscience-Twinning to develop state-of-the-art subsurface modelling capability and scientific impact) which is among else focused on modelling of EC transport in groundwater, a chance for synergy building between these two projects will enable experts to exchange experience and knowledge gained in the field of emerging contaminants.

Rad opisuje istraživanja provedena u prve dvije godine projekta ISSAH

Zavod za hidrogeologiju i inženjersku geologiju Hrvatskoga geološkog instituta (HGI-CGS-a) sudjelovao je u velikom broju projekata sufinanciranih od strane različitih EU programa koji su se bavili različitim aspektima istraživanja i zaštite voda. Važne su poruke, i naša motivacija za prezentiranje iskustava, činjenice da (a) istraživanja ove vrste imaju prioritet u mnogim programima te je moguće uklopiti se u definirane prioritetne osi različitih poziva ; (b) moguće je provesti direktne investicije i (c) moguće je sudjelovati u različitim ulogama (od podizvođača i pridruženih partnera do partnera i voditelja konzorcija), te se u svakoj ulozi mogu steći vrijedna iskustva. Rad će prikazati koja su sve istraživanja omogućena zahvaljujući ovom obliku financiranja te kako se različiti dionici i institucije mogu optimalno uklopiti u projektne konzorcije.

Through Interreg CENTRAL EUROPE project PROLINE- CE, interdisciplinary and innovative approach is demonstrated by applying integrated land use management scheme, linking together hydrochemical models, land use cover, climate change models and existing knowledge regarding best management practices for water protection and non-structural flood mitigation.

The term natural organic matter (NOM) refers to a group of organic substances that can be found in surface water and groundwater as a result of natural processes. In a major part NOM is a product of plant degradation and various other biological activities such as the metabolic activity of algae, protozoa, and microorganisms as well as excretion of fishes and other aquatic organisms (Bolan et al., 2011). In this paper, NOM has been observed as total organic carbon (TOC). Considering that the TOC is mainly contained in the soil zone, from the hydrogeological point of view it might be used as a tracer for infiltration. The behavior of tracer varies considerably between the high and low flow periods (Batiot, 2003a, Emblanch et al., 1998). The TOC concentration, chemistry, and composition in natural water are highly variable and depend on the sources of organic matter, the chemistry of the environment, ionic strength, pH, temperature, major cation composition of the water and on the presence of microbiological and photolytic degradation processes (Bolan et al., 2011). The determination of TOC concentration in an aqueous solution, such as a sample of wastewater or potable water, is important in different fields including pollution and industrial processing situations. Measurements were conducted for 17 months, from March 2018 to July 2019 at 9 springs in the northern part of the Dinaric karst in Croatia. The study case encompasses two hypsometric levels of spring and sinking zones of two karst rivers Dobra and Mrežnica. Former studies have shown the complex and heterogeneous karst system of the study area (Biondić et al. ; 1986 ; Bojanić, 1973 ; Bahun, 1968 ; Poljak & Herak 1947 ; Prelogović et al., 2005). The whole area is significantly disturbed by the tectonic activity. Main structures and faults generally have the typical Dinaric strike (NW-SE), in some cases N-S due to neo-tectonic activity (Prelogović, 2005). The natural hydrogeological dynamic of the aquatic ecosystem was additionally disturbed by the construction of hydro-technical infrastructure like tunnels, dams, and accumulations for hydropower plants. This complex karst system is defined as the boundary zone between deep and shallow karst zone (Bojanić, 1973 ; Kovačević, 2005). In deep karst zone, groundwater is located on a significant depth with complex and unpredictable flow-paths as a result of intensive karstification. In contrast, carbonate deposits in shallow karst zone are thinner, and impermeable deposits are more common (Tertiary flysch) causing this zone to be rich in surface hydrology with shallow groundwater levels (Bahun, 1968 ; Kovačević, 2005). In order to determine hydrodynamic processes, the following parameters were measured in situ: electrical conductivity (EC), pH, oxygen and temperature of spring water on the monthly base. Springwaters have been sampled and analyzed for cations (Ca2+, Mg2+, Na+, K+), anions (Cl-, SO42-, NO3-) and TOC in the hydrochemical laboratory of the Croatian Geological Survey. The scope of this paper is to show the preliminary results and initial relationship between total organic carbon (TOC) and other observed hydrogeological parameters.

Certain water quantity and quality related issues, which might subsequently arise due to irregular spatial distribution of water resources, can be further amplified in case of increased weather extremes and inadequate land use. The irregularity stems from specific and complex hydrogeological structures whose unique example is the Kupa River catchment area that can be divided in two diverse parts – alluvial and karstic. Alluvial area is characterized by intergranular porosity and groundwater flow through layers of variable thickness and composition. As opposed to alluvial area, karst is characterized by fracture-cavernous porosity and fast groundwater flow along preferential paths, low retention capacity, infiltration and discharge of water within the same groundwater body and high intrinsic vulnerability of aquifers due to lack of overlaying layers. The Kupa River catchment area is not only faced with adverse seasonal flood impacts but also inadequate land-use practices, which the population is not inclined to change. This coupled with hydrotechnical objects, which have strongly modified hydrological system and water regime, make water resources protection and flood mitigation even more challenging. Given the catchment’s transboundary character, achieving synergy between water management goals, spatial and economic growth while adapting them to climate change is one of Croatia’s sustainable development priorities, but also part of transnational efforts encompassed within CAMARO-D project (Danube Transnational Programme). As site specific best management practices implemented through the project’s lifetime, direct pilot area activities were hydrogeological field investigations, vulnerability mapping of Kupa River catchment area and climate change modelling (Turc (1954) and Langbein (1962) empirical models). A comprehensive vulnerability assessment was carried out with the help of GIS tools, by compiling and overlapping layers of natural (intrinsic) vulnerability and potential hazards of anthropogenic origin. The vulnerability and hazard assessment were based on good practices of previously renowned methods, esp. recommendations of European COST 620 project. As protection against floods is one of the main CAMARO-D objectives, hazard map was further overlapped with flood risk map. In addition, hydrological modelling of possible impacts of climate change on water resources was carried out. Correlation and comparison of measured (historical 1961-1990 and recent 1981- 2010) and modelled data for 30 year reference period (2041-2070) pointed out how hydrological regime of the Kupa River catchment is going to experience decreased discharge, more frequent extreme events and significant increase in temperature. Overall results were introduced to relevant decision makers and practitioners in the form of a catalogue of measures targeted at raising awareness and encouraging their involvement on a local, regional and national level.

ISSAH PROJEKT – ISTRAŽIVANJA HIDROGEOLOŠKIH SVOJSTAVA PRAPORA ISTOČNE HRVATSKE

Tracing tests are one of the most powerful tools in investigation of karst system hydrogeological properties (GOLDSCHEIDER & DREW, 2007). Tracing typically consists of injection of artificial tracer in a system of karst conduits and afterward monitoring of tracer concentration in discharging water of selected springs. Therefore, it directly reveals underground flow directions, velocities and dispersion within the system. However, considerably different results obtained from repeated tracings of the same sinkhole are common in karst areas (e.g. KUHTA et al., 2010 ; STROJ et al., 2010). Significant differences are commonly present in apparent groundwater velocities and dispersion, and sometimes even in groundwater directions. Inconsistencies in results of the repetitive tests are usually interpreted as a consequence of different hydrologic conditions within the system during performance of the tests. However, methodology of tracer monitoring in Croatia significantly evolved during 1980s: from detection of tracer using quartz lamp to detection using a laboratory spectrofluorometer. If properly used, spectrofluorometer enables much lower detection limit, i.e. much more reliable tracer detection at low concentrations. In recent years usage of field fluorometers also enabled high temporal resolution of sampling, and consequently determination of very detailed tracer concentration curves. Typically, tracer concentration curves show characteristic and relatively regular shapes, regardless if they are single or multi peaked. Therefore, highly irregular shape of tracer curves obtained by quartz lamp at concentrations close to detection limit gives rise to doubt in positive tracer detection. Within the karstic catchment of the Gacka river springs, several tracing tests were carried out over the time period from 1950s till present. Present knowledge about this regional and complex karst system is largely based on the results of these tests. Recently, a multi-tracer test in medium-low water conditions was performed. Usage of field fluorimeters together with hydrological monitoring enabled acquiring detailed tracer concentration and recovery curves. Despite relatively high tracer recovery, apparent ground flow velocities were much lower in comparison to the previous results. Comparison of results obtained in medium-low flow and in high flow conditions is particularly valuable for comprehensive estimation of karst system properties. Determined flow directions were quite different in comparison to some of the older results (reviewed in PAVIČIĆ, 1997), while they were consistent with more recent ones (KUHTA et al., 2010 ; KUHTA & FRANGEN, 2013). It can generally be concluded that caution is needed during interpretation of relatively old tracing test results considering determined tracer concentrations to detection limit ratio and concentration curve shape.

The main karstification processes are affected by the power of water and climate conditions. By gaining better understanding of denudation process as a main form of mechanical wear, the analyses chemical equilibrium and chemical kinetics of carbonate rock dissolution has greatly improved during last 50 years. However, natural conditions of rock exposure, as combination of climate, altitude, soil, vegetation, karst morphology, humidity, lithology, and surface morphology factors, have to be observed in natural environment. Within Interreg CAMARO-D project, part of the Kupa River catchment located in northern karstic part of Croatia, was chosen as case study area in which karst denudation rate will be observed on standard carbonate tablets.

Land-use practices can be considered as one of the main factors that impact and modify hydrological and hydrogeological systems, therefore affecting the quality and quantity of drinking water resources. Throughout Interreg Danube project CAMARO-D (Cooperating towards Advanced MAnagement ROutines for land use impacts on the water regime in the Danube river basin) and Interreg Central Europe project PROLINE-CE (Efficient Practices and Land Use Management Integrating Water Resources Protection and Non- structural Flood Mitigation Experiences) interdisciplinary approach is fostered with the intention of investigating intricate relations and impacts of land-use activities, climate changes and floods on drinking water resources. Transnational project partnership is comprised of research institutions covering a broad spectrum of affiliation, such as foresters, agronomists, hydrogeologists, spatial planners and ministries in order to address the common environmental issues in synergic manner. Drinking water resources in Croatia, generally considered being of good quality and quantity, are coming use increasing pressure due to improper land-use activities, climate changes and certain deficiencies in management (HRVATSKE VODE, 2016). As a response, within CAMARO-D and PROLINE-CE, specific areas are chosen for further investigation: (i) karstic part of Kupa River catchment and (ii) parts of South Dalmatia (from the Imotsko polje to discharge zone: Prud-Klokun- Mandina mlinica springs). Investigated areas are characterized by karst topography, with very complex hydrogeological forms and features, such as poljes, ponors, estavelles and preferential groundwater flow paths (LUKAČ REBERSKI et al., 2016). Aquifers in such karst terrains usually have high intrinsic vulnerability due to the lack of overlaying layers. In investigated areas the quality and quantity of drinking water resources is at risk due to impacts of adverse seasonal floods, hydrotechnical objects which have strongly modified hydrological systems and water regime, inadequate land-use practices and unfavourable climate change scenarios which point out to changes in trends of precipitation, temperature and discharge in near future. Locally, other issues include intensive agricultural activity in terms of plant protection products over-use (Figure 1.), high losses in water supply systems, illegal waste dumps, and inadequate collection and treatment of wastewaters (TERZIĆ & FRANGEN, 2017). In attempt to identify negative impacts of various types of land use, as well as to improve understanding of hydrogeological and hydrological processes in investigated areas, in situ measurements of physio-chemical parameters and hydrochemical laboratory analyses were conducted on spring and surface water. Hydrological modelling of possible impacts of climate change on water resources was carried in the scope of CAMARO-D and PROLINE-CE. Correlation and comparison of measured (historical 1961-1990 and recent 1981-2010) and modelled data for 30 year reference period (2041-2070) pointed out how hydrological regime of both investigated areas is going to experience decreased discharge, more frequent extreme events and significant increase in temperature (HORVAT & RUBINIĆ, 2003 & 2006). Additionally, in the scope of CAMARO-D, a comprehensive vulnerability assessment was carried out with the help of GIS tools, by compiling and overlapping layers of natural (intrinsic) vulnerability and potential hazards of anthropogenic origin. The vulnerability and hazard assessment were based on good practices of previously renowned methods, especially recommendations of European COST 620 project. As protection against floods is one of the main CAMARO-D objectives, hazard map was further overlapped with flood risk map (MAYER et al., 2019). With main gaps and conflicts between land use and water management being recognized, best management practices for drinking water protection are derived in order to achieve function-oriented land use-based spatial management at the operational level. Proposed best management practices are integral part of two major outputs of the projects, namely GUIDR (Guidance for the Danube Region for sustainable land use planning) in CAMARO-D and DriFLU (Drinking Water/Floods/Land use) Charta in PROLINE-CE.

Land-use practices can be considered as the pivotal factors that impact and modify hydrological and hydrogeological systems, forming an intricate relation which has a direct effect on the quality, quantity and availability of drinking water. Within the scope of PROLINE-CE project (Interreg CENTRAL EUROPE), interdisciplinary and innovative approach is fostered with the aim of improved protection of drinking water resources by applying integrated land-use management. Croatian drinking water resources, considered to be of good quality and quantity, are coming under increased pressure due to land use, climate changes and certain deficiencies in management. This is particularly relevant for Dalmatia – coastal region with Mediterranean climate, where prolonged droughts are common during dry and warm summer season. In response, two pilot areas were chosen: (i) Imotsko polje and (ii) part of South Dalmatia (Prud, Klokun and Mandina mlinica springs). Dalmatian pilot areas belong to Dinaric karst region, characterized by very complex hydrogeological features and forms, such as poljes (karst fields), springs, ponors (sinkholes), estavelles and preferential groundwater flow paths. In attempt to identify negative impacts of various types of land use as well as to improve understanding of hydrogeological and hydrological processes in pilot areas, in situ measurements of physio- chemical parameters and hydrochemical laboratory analyses will be conducted on spring and surface water. The main drivers in terms of negative effects on drinking water quality and quantity in pilot areas, as recognized through SWOT analysis, are intensive agricultural activity, high losses in water supply system, illegal waste dumps, outdated sewage system with high leakage, inadequate wastewater collection and treatment systems, occasional flooding of poljes and unfavorable climate change scenarios which predict reduction of discharge from 2021-2050. With main gaps and conflicts between land use and water management being recognized, best management practices for drinking water protection are derived in order to achieve function-oriented land use-based spatial management at the operational level. Proposed best management practices include improvement of groundwater monitoring systems, non-structural flood mitigation measures, innovative solutions of sustainable waste management, natural wastewater treatment systems, climate change adaptation and establishment of sustainable drinking water protection zones.

Insufficient understanding of hydrogeological, hydrochemical and dynamic relations of the Internal Dinarides in Croatia had a key role in selection of a case study for the project CAMARO- D (EU, Interreg Danube 2014-2020). New hydrogeological insights will be the basis for the future water management and flood protection of karstic part of Kupa River catchment area and its surroundings. Complex geological setting of the research area, which encompasses two hypsometric levels of spring and sinking zones, is mainly caused by structural-tectonic relations (and significant human interventions – tunnels, hydroelectric power plants, canals…). The case study comprised monitoring on 18 springs and 3 surface water- flows with the purpose to determine the hydrogeological characteristics of this complex aquifer system defined as the boundary between Internal and Outer Dinarides. The southern boundary of the research area is placed north of Kapela Mtn and Plitvice Lakes, northern boundary is the boundary between Dinaric karst and Pannonian basin in Croatia, while eastern and western boundaries coincide with state boundaries with Croatia and Bosnia and Hercegovina (East) and Slovenia (West) – partially following Una and Kupa rivers’ streams. This karst terrain is significantly different than other parts of the Dinaric karst terrains in Croatia. It is fluviokarst, often called shallow karst. Hydrochemical characteristic of groundwater has been studied by sampling and analyzing physic- chemical parameters: oxygen content, electrical conductivity, pH, temperature, total organic carbon, major anions (HCO3 −, Cl−, SO42−) and cations (Ca2+, Mg2+, Na+, K+), as well as heavy metals. In addition, stable isotope contents (δ18O, δD) is being monitored in spring and rain water in monthly intervals from beginning of 2018 till the end of 2019. Karstification processes of different rocks from this area will also be explored within this study. Geological and hydrogeological characteristic of this area will be presented in this paper, as well as first results of physic- chemical parameters in order to identify hydrogeochemical facies.

Water, as one of the most valuable and vulnerable part of the ecosystem, is of a special national interest in the Republic of Croatia. Nearly 90% of the total water quantity used to supply cities and settlements is derived from the groundwater resources. Therefore sustainable development which equally considers goals of water resources protection, spatial and economic growth while adapting them to climate change is of strategic significance and one of the Croatia’s paramount development priorities. As a transboundary river in Danube River Basin, Kupa and its catchment is not only subject of national but also transnational efforts of finding synergy and balance between rational land use, water conservation and flood risk prevention. Such transnational endeavours are encompassed with the CAMARO-D project (Interreg Danube), which develops a transnational catchment-based “Land Use Development Plan” (LUDP) for an adequate coordination and harmonization of different function-oriented sustainable land-use management activities. With the aim of overcoming main integrative management issues of Kupa river catchment, decision makers are faced with adverse land use and flood impacts within area of still insufficiently explored hydrogeological complex, so-called “the shallow karst”. In order to preserve intrinsic values of the water resources within the catchment area, the proclamation of certain protection categories is envisaged through legislation and protection instruments on various levels, such as nature and environment protection acts and physical planning documents, while protective and regulative water infrastructure (e.g. flood defence, melioration and water supply infrastructure etc.) are proclaimed as of importance for the state and county. Nonetheless, key stakeholder i.e. population being not inclined to changes, still hasn’t adjusted its land-use practices to hydrotechnical objects built in the recent past, which have strongly modified hydrological system and water regime (e.g. redistribution of flood prone areas). On that account, within CAMARO-D our focus will be on initiating site specific innovative solutions in the form of best management practices based on hydrogeological field investigations and vulnerability mapping of Kupa river catchment area. An insight into the hydrogeology of the area will be obtained with in situ measurements of physio-chemical parameters on main spring, surface and rain water, in monthly intervals and hydrochemical laboratory analyses. In this paper a comprehensive vulnerability assessment will be carried out with the help of GIS tools by compiling and overlapping layers of natural vulnerability and potential hazards of anthropogenic origin. Overall results will be introduced to stakeholders in the form of a catalogue of measures through various communication activities targeted at raising awareness and encouraging stakeholder involvement on a local, regional and national level.

Karst springs are characterized by a pronounced variability in flow and large sensitivity to the occurrence of long dry periods when their yield assumes extremely low values. This is especially important if these water resources are used for water supply. In this case the sustainable use of these water resources implies the need to estimate possible changes in water regime due to the impact of climate change. This kind of modelling and analyses of water balance was conducted for two pilot areas in the karstic part of Croatia within the DRINKADRIA project. The first pilot area is the river Mirna basin, where water supply sources Gradole, Sv. Ivan and Bulaž are analysed. Source Gradole is used for the water supply of a part of Istrian Region but also, in summer time, for the water supply of the Slovenian coast. The second pilot area is the water supply source Prud in river Neretva catchment. Spring Prud is located in Croatia, but only few hundred meters from the border with Bosnia and Herzegovina where almost all of its catchment is located. The paper presents the climate change impact assessment on these spring, as well as the overview of the most important results obtained. Three climate models (RegCM3, Aladin and Promes) were used for modelling the temperature and precipitation changes in the future (2021-2050) on pilot areas. Although there are some differences in their results (Promes climate model estimates the highest changes), all three models predict the air temperature increase and stagnation of precipitations. This causes the significant decrease in water balance of analysed springs that was estimated with hydrologic modelling. This decrease is obvious on the level of mean annual flow (up to 35%, for Promes input data), and even more emphasized on the level of minimum mean monthly flow (up to 60%, for Promes input data). Estimated results, as well as present needs for water in pilot areas emphasize the need to find additional measures to adapt to climate change, and find alternative solutions for optimal water management of analysed karst springs. Such modelling of water balance provides a prerequisite for the sustainable management of water resources in the possible upcoming situations, the occurrence of critical hydrological conditions. This model can be applied for similar assessments even in other localities.

Hidrogeološki sustav područja južne Dalmacije istraživan je do danas u više navrata. Posljednja istraživanja izvedena su prilikom istraživanja šire zone slijeva izvora Prud u sklopu projekta DRINKADRIA (IPA Adriatic CBC, financiran od EU) te u sklopu projekta „Hidrogeološka i paleolimnološka istraživanja Baćinskih jezera“ za investitora Hrvatske vode. Navedena istraživanja su doprinijela nizu novih spoznaja o ovom izuzetno kompleksnom hidrogeološkom sustavu. Cijeli slijev obuhvaća oko 1700 km2 , no kako se veći dio proteže na području Bosne i Hercegovine, ovim istraživanjima je obuhvaćen samo dio koji se nalazi na području Republike Hrvatske. Kako se krška područja odlikuju vrlo zamršenim hidrogeološkim i hidraulčĉkim odnosima, pri istraživanjima je potrebno primijeniti veći broj metoda koje će omogućiti dobivanje što realnijih zaključaka o hidrogeološkom sustavu koji se istražuje. Zbog toga su u sklopu spomenutih projekata, pored brojnih drugih hidrogeoloških istraživanja, napravljene i opsežne analize sastava stabilnih izotopa 18O i D podzemnih i površinskih voda na području slijeva, čiji su rezultati prikazani u ovom radu. Cilj izotopnih istraživanja je bio određivanje načina prihranjivanja, relativne visine područja prihranjivanja i utvrđivanje karaktera vodonosnika na temelju mjesečnih oscilacija vrijednosti stabilnog izotopa 18O. Istraživanja su zbog netipične hidrološke godine i relativno kratkog razdoblja opažanja nedostatna za konkretnije zaključke. No u isto vrijeme, zbog izrazito zanimljivih rezultata, ona predstavljaju temelj za buduća istraživanja ovog kompleksnog hidrogeološkog sustava.

DRINKADRIA project in South Dalmatia test area includes two catchments: spring Prud and Blatsko polje. All surrounding inhabited area is supplied by groundwater from these cathment areas.Water supply systems of spring Prud and Blatsko polje are typical seasonal with uneven consumption during the year. Maximum rates are always extracted in the summer seasons when the need for water is increased as a result of tourism and agricultural production, while the recharge in this half of the year is usually minimal or none. Human activities commonly affect the distribution, quantity, and quality of water resources. A broad range of human activities affects water resources. Major negative impacts on groundwater quality in these areas are agricultural activities and sea water intrusions. In this paper, the basic groundwater quality parameters of the investigated area are presented. Land use map, analysis of trends of major quality indicators was estimated to establish a negative influence on groundwater. Evaluated trends of changes in Corine land cover shows that there is no significant change in land use categories over the years.Trend analysis of chloride and nitrate has shown that values are quite dispersed at both sites, but long-term trends are negative or stagnating. In spite of this, due to the fact that water supply system of spring Prud is currently under construction which plans to double the amount of pumping, as well as the negative predictions of climate changes, it is necessary systematic monitoring and analysis of trends in water quality in order to timely detect possible adverse changes in water quality.

DRINKADRIA IPA ADRIATIC project studies territorial vulnerability and long- and short-term methods to safeguard groundwater resources in the Adriatic area. In the Croatian part of DRINKADRIA project, catchment of spring Prud is presented. Prud is a karst spring situated in south Dalmatia, close to the boundary with Bosnia and Herzegovina (BiH). Within the catchment boundaries there are several settlements. Karst geomorphology to which spring Prud catchment area belongs, is marked by great complexities and intertwinement of hydrogeological relations. Despite numerous investigations and tracing experiments in this system there are still a great number of uncertainties and doubts. The underground connection, surface streams that are sinking and appearing on the surface again, karst springs, estavelles or swallow holes present a big challenge for hydrogeological investigations.

DRINKADRIA IPA ADRIATIC project studies territorial vulnerability and long- and short-term methods to safeguard groundwater resources in the Adriatic area. In the Croatian part of DRINKADRIA project, catchment of spring Prud is presented. Prud is a karst spring situated in south Dalmatia, close to the boundary with Bosnia and Herzegovina (BiH). Within the catchment boundaries there are several settlements. Karst geomorphology to which spring Prud catchment area belongs, is marked by great complexities and intertwinement of hydrogeological relations. Despite numerous investigations and tracing experiments in this system there are still a great number of uncertainties and doubts. The underground connection, surface streams that are sinking and appearing on the surface again, karst springs, estavelles or swallow holes present a big challenge for hydrogeological investigations. Prud spring is the most important spring in the lower course of the Neretva River. It represents the basis of water supply in the regional aspect. This spring could supply nearly half a million inhabitants, but so far only 10% of its capacity is used due to construction capacity. Current system will be upgraded, which will achieve designed capacity, with almost doubled water consumption. Around 45 thousand people and just as many tourists in the top of the tourist season will be supplied by water from this catchment. This is one of the reasons why the necessity for preservation of this spring is of great importance. Land use is an important driver for determining water quality. From CORINE LAND COVER (CLC) for Croatia minor changes in land use can be seen. The most widespread land uses are agriculture and urban areas. Therefore, the most important driving forces are the use of fertilizers and nonexistent or ineffective sewage systems. The pressures they cause are release of microbiological pollutants, nitrogen and phosphorus compounds of nutrients, diffuse nitrogen contribution (runoff and percolation). Negative effect from agricultural areas and sewage systems is usually monitored through nitrate content. Despite a number of measures to improve groundwater quality in the Croatian part of spring Prud catchment, that are provided by competent county strategic plan, it is necessary to continuously and regularly monitor groundwater quality indicators. As the area has intensive agricultural production, and due to the fact that they are characterized by karst nature which is very sensitive to pollution, it would be highly preferable to increase organic agriculture in the future that will ensure the best preservation of underground water. This is important not only for the people, but for the entire ecosystem.

Krški teren desne obale rijeke Neretve obilježen je izrazitom složenošću i isprepletenošću hidrogeoloških odnosa. Unatoč brojnim istraživanjima i trasiranjima podzemnih tokova u ovom sustavu još je uvijek prisutan veliki broj nepoznanica i nedoumica. Podzemne veze, površinski tokovi koji poniru i ponovno se pojavljuju, krška vrela, estavele i ponori, i danas predstavljaju izazov za hidrogeološka istraživanja. Pri novim istraživanjima tako su korištene brojne prethodno objavljene publikacije među kojim se ističu: BONACCI et al. (2013), IVIČIĆ (2000), i SLIŠKOVIĆ (2014). Nedavna istraživanja provode se sa svrhom rasvjetljavanja ovih složenih međuodnosa, u području od slijeva Mostarskog blata na sjeveru i slijeva izvora Opačac na zapadu, pa sve do zone izviranja: od Gradca (Mandina mlinica), preko Baćinskih jezera i Klokuna, do Modrog oka i manjih izvora u Desnama, do snažnog krškog vrela Pruda kod Metkovića. U suradnji s kolegama iz Instituta za hidrotehniku iz Sarajeva analizirani su i stalni i povremeni ponirući tokovi, prvenstveno Vrioštice, Tihaljine i Trebižata, pa sve do Lištice i Mostarskog blata. Svrha istraživanja, osim upoznavanja ovih podzemno-površinskih odnosa, zapravo je zaštita brojnih vodoopskrbnih izvora u slijevnom području (Butina, Banja, Klokun, Modro oko, Prud), zaštita ekosustava Baćinskih jezera, te predlaganje rješavanja prekogranične zaštite između Hrvatske (HR) i Bosne i Hercegovine (BiH). Opsežnom hidrogeološkom analizom, s obilnim korištenjem hidrokemijskih i izotopnih podataka, te novim i starim trasiranjima podzemnih tokova, sustav je shematski podijeljen u dijelove (podsljevove ; Slika 1): (1) slijev Mostarskog blata u dva podsljeva, a zapadni dio (1a) podzemno utječe na južne izvore, (2) slijev Trebižat- Tihaljina, također u dva dijela gdje samo najistočniji dio (2b) ne utječe na izvore u istraživanoj zoni, (3) malog izravnog slijeva Pruda, (4) slijeva Modro oko-Klokun koji se proteže relativno daleko na zapad iza Biokova i Makarskog primorja, (5) neposrednog slijeva Baćinskih jezera i Mandine mlinice, te (6) izvora Opačac koji izravno doprinosi vodama Tihaljine. Nakon hidrogeološkog postavljanja ovakve razdjele, hidrološkim je bilanciranjem utvrđeno kako značajan udio voda koje se infiltriraju u sjevernim podsljevovima u BiH ulazi u sljevove Pruda i južnijih izvora sve do Mandine mlinice. Hidrokemijski podatci su dodatno potkrijepili činjenicu o povezanosti izvora u HR s vodonosnicima u BiH preko povišenih koncentracija sulfata koje opadaju „stepenicu-po-stepenicu“ prema jugu, a posljedica su otapanja gipseva i anhidrita u hercegovačkom krškom podzemlju. Temeljem cjelogodišnjeg opažanja, povremenim uzorkovanjima i laboratorijskim analizama, te mjerenjima protoka i razine automatskim mjeračima (tzv. logerima), došlo se do značajnih spoznaja. Opažanja se u ponešto smanjenom intenzitetu nastavljaju.