Nataša Ravbar, born in 1976, is a Research Fellow at the Karst Research Institute of the Scientific Research Centre of the Slovenian Academy of Sciences and Arts (Postojna, Slovenia). She has been interested in karst landscapes since 1996 when she joined a local caving club. She graduated in 2001 at the Department of Geography and at the Department of African and Asian Studies, Faculty of Arts at the University of Ljubljana and the same year continued her studies at the Graduate Programme Karstology, Faculty of Graduate Studies at the University of Nova Gorica. In 2002 she was included in the Karst Research Institute research group as a young researcher being involved in national and international projects. Her main research interests are karst hydrology, water supply problems and the protection of karst waters against contamination. An important part of her work is studying the properties of karst groundwater flow. She defended her doctoral dissertation in 2007 and she became lady vice-chairman of Karst Commission at the International Geographical Union the following year. Her research activities are supported by the World Federation of Scientists and the Slovene Scientific foundation.
Abstract: This paper presents utilization of several different investigation techniques to better characterize karst environment. Geomorphological mapping, together with structural and lithological mapping, and electrical resistivity imaging have been carried out in a selected test site in order to evaluate intrinsic characteristics of a karst area. Identification, positioning and quantification of morphometrical properties of karst and other landforms have been determined. Tectonic deformations and lithological contacts of karst and non-karst rock have been precisely located. The extent and depth of the sediments have been examined. The results of mapping and electrical resistivity measurement have been arranged in comprehensive GIS database. The benefit of multiple investigation techniques application has been demonstrated. Employing a combination of methods revealed information on hydrogeologically most sensitive zones that were later used for comprehensive vulnerability and risk mapping, as well as groundwater tracing planning. Gained data provided new achievements in geophysical characterization of the studied area in the western outskirts of the Snežnik aquifer, in particular the Podstenjšek spring catchment. Findings can also be utilized to better understand relief evolution and can serve as a basis for various thematic and applied studies.
Abstract: In the catchment area of the Unica River two combined tracer tests with fluorescent dyes have been performed aiming to characterize the properties of groundwater flow and transport of contaminants through the vadose zone and well developed system of karst channels in the epiphreatic and phreatic zone in different hydrologic conditions. Tracers were injected directly into the ponors and to the oil collector outlet on the karst surface. Prior to tracing monitoring network has been set up, including precipitation, physical and chemical parameters of the springs and cave streams. Field fluorimeters were used to detect tracers in the underground river and conventional sampling techniques and laboratory analyses were used at the springs. Some of the results were quantitatively evaluated by QTRACER2 Program. During the first tracer test, when injection was followed by rain event, flow through the well conductive cave system was characterized by apparent dominant flow velocities of 88â640 m/h. Breakthrough curves were continuous, uniform and single peaked, and almost complete recoveries were observed. During the second tracer test, when water level was in constant recession, the transport velocities through the well developed karst conduits were significantly slower (apparent maximal flow velocities being 2â4 times lower). Results also show lower dispersivity during the second tracer test, which corresponds to lower flow velocities. The tracer injected at the karst surface arrived with the expected delay (vdom around 9 m/h) and showed irregular and elongated breakthrough curves with secondary peaks. In this paper only tracer test results are presented, which are a part of a comprehensive study of groundwater flow through the complex karst aquifers aiming at improving karst water resources understanding, protection and management. The presented assessment will beyond be utilized for further detailed analysis, studies and modelling.
Abstract: The study presents natural hazards in Sloveniaâs karst, focusing on flooding in karst poljes. A specific study was done on the flood dynamics of two typical and connected karst poljes (Cerknica and Planina) of the Classical Karst region. In the case of particularly extreme hydrological conditions in the autumn of 2008, detailed analyses of the recharge-discharge regime and the interrelationship of flooding on the two poljes were done. Daily precipitation, discharge, and water level values from several monitoring sites were analyzed and cross-correlated, and additional hydrological analyses were done using a digital elevation model in order to acquire water level increase and decrease intensity, flood water volumes, and the extent of flooding and to understand the conditions controlling karst flooding. The results reveal that the hydrological functioning of the studied karst poljes is influenced by the hydrogeological and temporary hydrological conditions in the catchment area. The response of the binary karst system (i.e., the influence of autogenic and allogenic recharge) is especially distinct. The study shows that during extremely intense recharge, the reactions of karst aquifer systems to precipitation are as rapid as the response of surface waters (the water level of Cerknica Lake increased with an intensity of 38-63 cm/day or 55 m3/s respectively) while retention capacities are negligible. In contrast to flash floods, floods in karst areas may last from several weeks to several months. For the observed period a three-dimensional simulation of the flooding was made. At the maximum recorded water level, the volume of water on the Cerknica polje was 51 million m3, and 26 million m3 on the Planina polje. The maximum extent of flooding on the Cerknica polje was 23 km2 and on the Planina polje 9.5 km2. On the basis of the study, information was provided regarding future hazard mitigation. However, the study demonstrated that a sufficiently dense monitoring network is necessary to predict the occurrence and duration of floods with greater certainty.
Abstract: The vulnerability of four European aquifers with different hydrogeological and climatic characteristics was evaluated using COP method. The results obtained were statistically analyzed by determination coefficients to measure which factor has a greater importance in the vulnerability index. Furthermore, a new parameter has been designed to measure the vulnerability for the whole of the aquifer. The results demonstrate that COP is a useful method to assess the vulnerability of the test sites under consideration. The results obtained are coherent with the conceptual model of each pilot aquifer and the available hydrogeological information (hydrographs, isotopic data, tracer tests). Fissured carbonate aquifers (diffuse flow systems) are less vulnerable than karst aquifers (conduit flow systems) and the vulnerability index is more positively correlated with the O factor (unsaturated zone protection capacity) in the first case. The karst aquifers are more vulnerable than fissured aquifers and they show a higher correlation between the C factor (karst features) and the vulnerability index. Climatic variation (precipitation for example) influences the final vulnerability index of the aquifers according to the weight in the index and the spatial distribution.
Abstract: Four methods of groundwater vulnerability mapping have been applied in a Slovene karst catchment and validated by tracer tests. The test site is characterised by high water table fluctuations, manifested in intermittent
lakes and variable drainage divides. A first multi-tracer test (two injections) allowed subdivision of the catchment
into zones of different degrees of contribution (âinner zoneâ and âouter zoneâ). For vulnerability mapping, only methods that consider the specific nature of karst aquifers such as heterogeneity and duality of infiltration processes, were selected: EPIK, PI, the âSimplified Methodâ and the âSlovene Approachâ. For validation, a second multi-tracer test (four injections) was carried out. The time of first detection and the normalised recovery were used as validation criteria. The results suggest that EPIK and the Simplified Method sometimes overestimate vulnerability, while PI and the Slovene Approach tend to deliver more realistic results, at least during low-flow conditions. The Slovene Approach gives the clearest guidance on how to deal with hydrologic variability, for example by assigning lower vulnerability to occasionally active sinking surface waters than to permanent ones. As a conclusion, commonly accepted validation techniques are needed and should be applied by default to evaluate different vulnerability mapping methods and the resulting maps.
Abstract: A step from resource to source vulnerability mapping is presented, based on the European COST Action 620 approach for karst groundwater protection. Guidelines on vulnerability assessment of the horizontal groundwater flow path within the karst saturated zone (K factor) are proposed. By integrating this into the previously existing COP method for intrinsic resource vulnerability mapping, adequate source protection can be assessed. The proposed âKarst saturated zone (K) factorâ assessment considers groundwater travel time (t subfactor), connection and contribution to the source (r subfactor) and active conduit or fissured network (n subfactor). The extended COP method was applied in two carbonate aquifers in southern Spain with different geological, hydrogeological and climate settings. The results are coherent with previous research results of the studied areas. Moreover, they are consistent with the occasional groundwater contamination detected in one of the springs. On the other hand, an absence of contamination, despite high risk, justifies the lower degrees of vulnerability assigned to the sources surveyed. The source vulnerability maps obtained can thus be used as a basis for the delineation of protection zones.
Abstract: On the basis of work accomplished by the European COST Action 620, a comprehensive approach to groundwater vulnerability and contamination risk assessment is proposed, taking into account the special characteristics of Slovene karst aquifer systems. The Slovene Approach is consistent with national environmental legislation and enables comparison across European countries. The method integrates temporal hydrological variability in the concept of groundwater vulnerability and offers a new possibility to combine surface and groundwater source and resource protection, which required the development
of a new K factor (karst groundwater flow within the saturated zone). The risk analysis considers intrinsic vulnerability, contamination hazards and the importance of the source or resource. It has been first applied to the Podstenjšek springs catchment in southwestern Slovenia and validated by means of two multi-tracer tests with a total of six injection points. The resulting vulnerability, hazard and risk maps are plausible, and the validation confirmed the vulnerability assessment at the representative sites that were selected for tracer injection. The maps provide improved source protection zones and make it possible to identify land mismanagement and to propose better practices for future planning.
Abstract: Slovene karst sources are of great national importance for drinking water supply. Since karst aquifer systems are very susceptible to contamination, these sources require appropriate and careful managing. Unfortunately, in the acts of Slovene legislation, the special characteristics of water flow within karst regions are not very seriously taken into consideration in determining the criteria for karst water sources protection. In contrast, in some other countries, the concept of groundwater vulnerability mapping has been successfully used for protection zoning and land use planning in karst. Regarding the differences between particular karst aquifer systems, data availability and economic resources, different methods of karst water vulnerability assessment
and mapping have already been developed. Already these methods have been many times tested and implemented in different test sites worldwide.
However, experience in application using different methodologies for vulnerability mapping of karst aquifers is very modest in Slovenia. The present paper deals with potential methodological problems that might arise while applying the most commonly used methods for karst water vulnerability assessment to Slovene karst regions.
Abstract: The article presents potential and actual sources of groundwater contamination on the Kras plateau, which is the recharge area of the Klari~i karst water source that provides drinking water for the Kras plateau and Koprsko primorje. The water source is insufficiently protected due to inadequate water protection policy and the control over the implementation of the provisions has often been ineffective. Untreated wastewaters, illegal waste-disposal dumps and traffic endanger the water source. The hazards are shown on a simplified map that could be, in a suitable scale, a valuable practical tool for further water source protection and in land-use planning.
Abstract: Slovenian karst areas extend over 43% of the country; limestones and dolomites of the Mesozoic era prevail. In Slovenia karst groundwater contributes up to 50% of the total drinking water supply. The quality of water is very high, despite the fact that it is extremely vulnerable to pollution. The present article is a study and a review of the potential and actual sources of pollution to the groundwater in the selected karst aquifers (the Kras, Velika planina and Snežnik plateaus), which differ in their natural characteristics. Unlike the other selected plateaus, the Kras plateau is inhabited. There are several settlements in the area and the industrial, agricultural and traffic activities carried out that represent a serious threat to the quality of karst groundwater. The Velika planina and Snežnik plateaus do not have permanent residents, however there are some serious hazards to the quality of the karst springs arising from sports, tourist, construction and farming activities, as well as from the traffic related to them. Despite relatively favourable conditions for protection, many important karst aquifers and springs are improperly protected in Slovenia. The reason is the lack of knowledge about sustainable water management in karst regions and the confusion in drinking water protection policy.
Abstract: The present paper presents the hazard mapping of groundwater on the Velika planina alpine karst plateau. There are no permanent residents on the plateau. Nevertheless, some serious hazards to the quality of the respective karst springs are arising from sports, tourist and farming activities. Some pollution has been already recorded in springs, showing the shortcomings of drinking water management also in uninhabited alpine karst areas, which are ordinarily very favourable for water protection.
Abstract: In the past the biggest economic problem on the Kras plateau used to be drinking water supply, which has also
been one of the reasons for sparsely populated Kras plateau. Today the Water Supply Company provides drinking water to households and industry on the Kras plateau and the quantity is suffi cient to supply the coastal region in the summer months as well. Water supply is founded on effective karst groundwater pumping near KlariÄi. Some water is captured from karst springs under Nanos Mountain as well.
In water supply planning in future, numerous other local water resources linked to traditional ways of water supply need to be considered. Eventual rainwater usage for garden irrigation or car washing, for communal activity (street washing) or for the needs of farming and purifi ed wastewater usage for industry (as technological
water) is not excluded.
Abstract: At dry season the Pivka river appears between Prestranek and Rakitnik while near Zagorje the underground
karst waters are about ten meters below the valley bottom of periodical Pivka river. High waters pour over the
surface and fi ll stream valley of the Pivka river, which runs continually from Zagorje to the ponor of Postojnska
jama. When the level of the underground water increases, also shallow karst hollows â uvalas are fl ooded and
changed into more than 15 periodical karst lakes.
Abstract: The first real scientific exploration of karst and karst caves in south China was undertaken by Xu Xiake (1587
- 1641). Chinese karst was studied by Xu Xiake for more than thirty years. He described his journeys to
almost half of the territory of the Ming dynasty in his book ÃXu XiakeÃs travelsà (ÃXu Xiake youjiÃ), that
was first published in 1642. He dedicated a lot of time to the research of the underground world by describing
subterranean rivers and lakes as water resources. He also made ground plans of some caves, marked their
entrances and described different shapes of speleothems. He first described different ways of climbing in
caves and methods for cave research. Altogether he visited over 300 caves. Xu Xiake first described different
types of the tropical karst and focused on the characteristics and reasons of the tower hills origin. He introduced
the term fenglin (peak forest), which is still used in the scientific literature. However, he is not only the
father of the modern speleology, karstology, geomorphology and geography in the Chinese scale but in a
worldwide sense.
Abstract: The concept of karst aquifer vulnerability mapping is commonly used for the determination of water protection
zones and planning of land use in the background of the captured karst sources and wells. Several different
methodologies for karst aquifer vulnerability mapping exist and the examination of scientific literature shows
considerable variations in the definition of the term vulnerability. The authors suggest the distinction between
the terms vulnerability and sensitivity of karst aquifers, since the former includes more information, which
are required for efficient protection. The interpretation of the applied terms is founded on the conceptual
background of the environmental vulnerability studies, which are declared with the Slovene 1993
Environmental Protection Act.
Abstract: Water supply in Koprsko primorje is being founded on efficacious karst springs Rižana and Gradole and karst underground water, which is pumped in KlariÄi. Because of the increased need of drinking water, problems of water provision appear, especially in summertime. Enormous and still growing consumption of drinking water in Koprsko primorje is forcing into search for new efficacious water resources.
Abstract: Dolines are the most typical geomorphological feature of the karst relief in the temperate
zone. Dolines vary greatly in their morphology and origin from (1) solution dolines and (2)
Âinherited dolines (formed by the exposure of underground caverns through surface erosion)
to (3) collapse dolines. This article deals with the dolines in a selected area on the Kras
plateau in southwestern Slovenia.
Using geomorphological field mapping, we obtained the distribution, density, size, and depth
of the dolines and tried to define their origin. A comparison was made between the dolines
according to the local lithology, slope inclination, and exposition.
The average density of dolines on the Kras plateau is well over fifty dolines per km2, and in
some smaller areas the density reaches more than 240 dolines per km2. Most dolines in the
area studied are solution dolines. They developed as surface features of the epikarst zone due
to the locally more intense solution processes. Their density depends primarily on the local
lithological conditions and slope inclination.
In the area studied, the cave density is among the highest in Slovenia, reaching up to 2.4 caves
per km2.
Abstract: Good knowledge of terminology in different languages is indispensable to be able to present correctly the
results of scientific work, for international cooperation of experts and for translating professional texts. Purpose
of the present article is to represent the typical Chinese karst landscape and to explain the terms used in
the country. Although karst researches in China are carried out separately from the karst-sciences of western
countries, terms such as fengcong, fenglin, shilin are enforcing gradually into international karst terminology.
Question how to introduce new terms into narrower professional public sphere with old terms already established, is still remaining open. Sometimes this is necessary since a new term is of somehow enriched meaning or is gathering more information and improving the understanding. Appropriateness of such decision should be estimated by further discussions, which should be based upon familiarity with the problem and not upon the sentimentality towards the terms, if these have born more general meaning up to this time.
Abstract: As it is expected the global warming to induce changes in hydrological regimes, the presented study has been conducted to understand how karst groundwater resources may be affected during long-term dry period. A multi-tracer test with three injection points aimed at identifying the dynamics of underground drainage through well developed system of karst channels and through vadose zone. Results show low apparent dominant flow velocities (through well developed karst conduits between 5.9 and 22.8 m/h, through vadose zone 3.6 m/h), multiple peaked and extended breakthrough curves. These findings are relevant for groundwater quality monitoring, protection and management, as they infer that contaminant transport in karst, at least in the studied area, may be retarded and long-lasting.
Abstract: The present paper presents the impacts of pasturing on karst groundwater quality on the Velika planina alpine karst plateau. There are no permanent residents on the plateau. Nevertheless, some serious hazards to the quality of the respective karst springs are arising from sports, tourist and farming activities. According to data the later do not pose a serious threat to the quality of karst groundwater. Some pollution was already recorded in springs, showing the shortcomings of drinking water management also in uninhabited alpine karst areas, which are ordinarily very favourable for water protection. The most significant hazards are presented in a simplified map.
Abstract: An extensive analysis of drinking water household users has been performed in 2003 in south-western Slovenia.
The most important goal of the present research was to deepen the understanding of the socio-cultural,
economic and technological characteristics of drinking water consumption. Thus we can deduct as regards the
factors, which can cause a change in the treatment of water resources. The behaviour of household water users
(habits in drinking water use), the attitude towards water (ecological awareness) and how the users would
respond to changes in water quality, water supply quality, water price and similar have been investigated.
Household users present the most numerous group of drinking water users, and are also the most demanding
and sensitive users. Data on how water problematic is sensed in the households was collected in the course of
opinion poll survey (421 completed questioners).
It has turned out that the respondents are well aware of the importance of drinking water for their life. They are
also well aware of the negative human impact on the environment and the urgency of economical treatment of
drinking water. Although the majority treats drinking water as economical as possible, each individual
consumes over one hundred litres of water daily, which is believed rather uneconomical than neglecting use. If
the users will not start treating drinking water more reasonably, the stock of clean water could soon reach
critical limits. This paper reviews the characteristics of drinking water consumption of contemporary users and
their relation to the water problematic through the behaviour of the respondentsâ sample.
Abstract: The present article presents the historical development and the contemporary condition of water supplies from
the karst water resources in south-western Slovenia. Data as regards the water resources that are intended for
water supply is provided. The final results regarding the use of water, the extent of the waterworks networks, the
distribution of drinking water, the number of people that are supplied by the individual sources and the data
regarding the quantity as well as the aim of the used water in the researched area is presented.
In the studied area water gained from the karst water resources is more than 95 %. Somewhere their capacities
are not fully taken yet and present an alternative water resource in the future. In order to preserve sufficient
quantities and satisfactory quality of the karst groundwater for the future generations it is important to make
users acquainted with significance of the karst resources sustainable management.
Abstract: Existing methods on karst groundwater vulnerability mapping take into account a variety of factors that control the infiltration of water and contaminants from the land surface towards the groundwater, such as overlying layers, concentration of flow, karst network development, and precipitation regime. Karst systems often show fast and strong hydrologic variations in response to precipitation events or snowmelt. Although such variations are crucial for contaminant transport, existing methods provide insufficient tools to cope with hydrologic variability. Examples from Slovene karst landscapes are presented, which are characterised by strong hydrologic variations, including groundwater level fluctuations, changing flow directions, intermittent lakes, some of which appear several times per year while others occur only very exceptionally, as well as temporary springs, swallow holes and estavelles. It is demonstrated why and how these variations are relevant with respect to contaminant transport and groundwater vulnerability. Finally, it is outlined how temporal hydrologic variability could be considered within the framework of karst groundwater vulnerability assessment and land use planning.
Abstract: In Slovenia karst water sources contribute up to 50 % of the total drinking water supply. In dry period of the year this amount reaches about 2/3 of the total consumption. The quality of karst water is still relatively high, but some signs of contamination have already been recorded in some of the springs.
The respective karst aquifers are mainly in remote areas and are due to their relief or unfavourable climate conditions less attractive for intensive settlement, industrial, farming and other activities. Despite relatively favourable conditions for karst water sources protection in comparison to some other karst areas worldwide, many of the karst water sources still remain insufficiently protected. The reason is the disorder in water protection, conflicting interests in land use and the lack of knowledge about sustainable water management in karst regions.
Abstract: Karst aquifers are very complex in comparison with non-karst ones. Due to their specific structure, flow of the groundwater is unpredictable and its reactions to contamination can be very diverse. The response of the karst environment and its constituents to anthropogenic contamination is very specific and characteristically differs from that of other environments, because travel of contaminants through the phreatic and vadoze zones is unpredictable. An eloquent proof is the case of the spill of several thousand litres of dangerous substances in the immediate vicinity of the GloboÄec spring in June 2004 that even after heavy rains did not affect the water quality of the spring.
GloboÄec is a typical karst spring that supplies inhabitants of the Suha krajina karst plateau and of the Krka river valley. Most of the catchment area consists of deeply karstified, heavily fractured and well permeable Jurassic and Cretaceous limestones. In case of serious contamination of the spring near 4,700 people of Suha krajina and the Krka river valley would stay without drinking water, because there is no alternative water source available.
Abstract: A general approach for karst water vulnerability and contamination risk assessment has been proposed, taking into account the special characteristics of Slovene karst landscapes, suiting Slovene environmental legislation and enabling comparison across European countries. The so-called Slovene Approach has been developed on the basis of work accomplished by the European COST Action 620. It incorporates the strongly modified COP method for intrinsic vulnerability assessment by integrating temporal hydrological variability, offering a new possibility to combine surface and groundwater protection, as well as by adapting it to source vulnerability mapping. The methodology provides also comprehensive risk analyses based on the intrinsic vulnerability, hazard and (re)source importance assessments. The proposed Slovene Approach has been first applied to the PodstenjÅ¡ek water source catchment. Different other methods have been applied (EPIK, PI, COP, Simplified method) and compared. For the catchment area delineation, application of different vulnerability and risk methods a holistic research of the test site has been done by means of tracer tests, detail structural-lithological and geomorphological mapping, electrical resistivity imaging, as well as detail hazard mapping. Continuous monitoring of the springsâ physico-chemical characteristics has been performed for the hydrograph analyses, water balance calculation and aquifer behaviour comprehension. The resulting Slovene Approach intrinsic vulnerability, hazard and risk maps are justified and validation with tracer tests has proved the method to give plausible results. The resulting maps provide improved source protection zones determination and identification of land mismanagement, as well as reorganisation and better practices for future planning.
