Projects / Programmes
Use of tracing with environmental and artificial tracers in planning of the protection of karst waters
| Code |
Science |
Field |
Subfield |
| 2.20.00 |
Engineering sciences and technologies |
Hydrology |
|
| Code |
Science |
Field |
| P005 |
Natural sciences and mathematics |
Geology, physical geography |
karst waters, tracing, information database, vulnerability, protection, monitoring
Researchers (8)
Organisations (1)
Abstract
Karst waters are the main source of drinking water in Slovenia and they supply more than a half of the inhabitants. They are very vulnerable to various sources of pollution, therefore they should be properly protected, and the long-term plan of protection should be based on a profound knowledge of the characteristics of water flow and transport of substances through the karst. In numerous previous studies the tracing with natural and artificial tracers was proved as one of the most adequate methods for such studies. In the proposed project we will test the applicability of this method in three important phases of the preparation of expert basis for the karst water protection: assessment of intrinsic and specific vulnerability, and planning of the monitoring of the quality of karst waters. The study area will be the karst water system in the catchment of the Malenščica spring. In the past numerous tracings with artificial tracers were carried out on Slovene karst, and first their results will be collected and critically evaluated. Different GIS tools will be used to incorporate the existing data into an information database, which will then be very useful for application in planning of different interventions on karst and protection of its natural resources. The existing database will be supplemented with some new field, cabinet and laboratory observations. Tracing with natural tracers will involve detailed monitoring of natural parameters of karst waters in different points of the recharge area of the Malenščica spring, and parallel with these observations a combined tracer test with artificial tracers will be carried out. Based on the interpretation and comparison of obtained data the influences of different types of recharge, characteristics of unsaturated zone, relations between surface and underground waters, and flow through karst channels on the intrinsic vulnerability will be assessed. The specific vulnerability is based on natural characteristics of the aquifer also, but additionally it takes into consideration the properties of the contaminant. For the selected sources of pollution some specific contaminants will be defined first, and then different types of their infiltration into the underground will be considered. We will test the applicability of various methods of tracing for the study of transport and retardation characteristics of selected specific contaminants in karst aquifers. Based on our existing knowledge and collected new results the guidelines for the planning of monitoring of the quality of karst waters will be prepared. Especially the impact of variations of hydrological conditions on physical-chemical properties of water will be studied, because understanding of this relation is crucially important for efficient and representative monitoring.
Significance for science
Expected results of the proposed project are important for the development of the methodology of tracing with natural and artificial tracers. The review of the state-of-the-art of the knowledge and the frequency of use of this method on Slovene karst is based on a detailed and critical assessment of the results of previous tracings. Numerous problems in the application were detected. Above all in weak preparation of the test which should be based on proper hydrogeological researches, as well as in the premature ending of the sampling. Especially in the past the duration of sampling was limited to the detection of the first tracer breakthrough peak, and this is often the case also today. But a detailed review of the findings of previous tracer tests and the analysis of the results of the performed combined tracer tests on the selected study area indicated that flow paths, which are activated only in extreme hydrological conditions, can only be detected by long lasting test. With the tests of longer duration also the long lasting washing out of the tracer or a potential pollution from the karst water systems were proved.
The importance of the study is also in the search of new possibilities for the use of tracer tests in dealing with the specific problems of vulnerability and protection of karst water resources. With performed and additionally planned analyses the influences of different types of recharge, characteristics of the vadose zone, relations between surface and underground waters, and the flow through karst channels on the intrinsic vulnerability are tested. Obtained results are the basis for the improvement of the method of vulnerability mapping and its validation. Interesting results were obtained by the comparison of the results of two combined tracer tests (fluorescent dyes as artificial tracers) and parallel measurements of physical-chemical parameters (electrical conductivity and temperature as environmental tracers).
Analysis of various hydrological time series indicated that the extent of the recharge area may have an influence on the memory effect and storage capacity of individual karst springs; the smaller systems have quicker, more intensive and short-lasting reactions on precipitation events in the comparison with the larger ones. The type of recharge has an additional influence on the storage capacity. Therefore it is very important to interpret the results of the time series analysis together with the results of other methods used in karst hydrology. Important are methodological conclusions about the importance of selection of time series (importance of precise planning of field measurements to get quality data, influence of different hydrological conditions in selected time intervals, advantage of selecting longer time-series in simultaneous intervals for comparison of the characteristics of various karst systems) on the results of analysis. Innovative is also the idea for using the cross-correlation analysis of time-series of electrical conductivity in sinking streams and springs for the assessment of groundwater flow velocity, which could to a certain extent substitute the results of tracing with artificial tracers.
Significance for the country
Slovenia is a karst country and more than a half of its inhabitants is supplied with drinking water from karst aquifers. Important are also big reserves of high quality karst water, which are still not used. The protection of water quality is essential also for the conservation of biodiversity in this sensitive environment. Especially springs as one of the most typical and picturesque karst phenomena are an important part of our natural heritage. One of the most important tasks of our society is therefore a proper protection of this water wealth against pollution. Tracer tests are an efficient method for the study of the characteristics of groundwater flow in karst and the information database of tracer tests will facilitate the access to their results. With the help of the GIS base it is possible to quickly evaluate the danger of spreading of the pollution from the point source, and a more detailed look into the database enables the use of valuable information also in some applied projects of the planning of different interventions into karst environment or protection of water resources. The database is an efficient tool for the planners of human activities or landuse on local or national level, and the proposed guidelines for the use of tracer tests in different phases of protection of karst water resources facilitates to potential users also the planning and organisation of tracing in praxis. Very good results were obtained by a parallel application of artificial and environmental tracers. Namely, on the basis of our new findings it is possible to improve the methodology of research of the vulnerability of karst aquifers, which is the basis for their efficient protection.
Additional benefit of the project is its educational function. Results of a long-term scientific research were collected and then presented in an accessible and understandable way, so that also wider public will be able to use them. In karst the groundwater is hidden deep in the underground and for many people it is difficult to imagine the branching of underground water connections and wide extent of the recharge areas of important springs. Constructed map with the results of tracer tests and GIS data linked to it clearly present these characteristics and improve the understanding of the vulnerability of karst water resources to different sources of pollution. As the awareness of public is a prerequisite for the efficient implementation of prescribed protection measures, the results of the proposed project will contribute to more effective protection of karst waters.
Slovenia is a country of classical karst and on Kras also karstology as a research field started to develop. First tracer tests in this area were carried out in the beginning of 20th century, and since then different scientists and organisations have performed more than 200 tracings. The information database of tracer tests is therefore as a historical review of the use and development of this research method very important for the proper presentation of scientific achievements of Slovene karstology, which is well recognised also internationally.
Most important scientific results
Annual report
2008,
2009,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2008,
2009,
final report,
complete report on dLib.si
