Karst Vulnerability Assessment
Introduction
Karst terrain accounts for a significant portion of the global land surface at all latitudes and at all elevations. It has been estimated that about a fifth of the world’s dry, ice-free land is karst. In Europe karst areas cover about a third of the continent and are an important natural heritage and source of groundwater. Karst aquifers are typically very vulnerable to pollution, with the result that life in the karst brings a series of risks and restrictions. Studying and understanding the processes that take place in the karst hydrogeological systems is a key basis for their conservation through adequate measures for protection and sustainable use (Ford & Williams 2007). To effectively maintain the quality water sources, it is the most important to identify and yield precedence protection to the most sensitive areas of their catchments. In karst aquifer, complementary or compensatory to the transit time or distance criteria the concept of groundwater vulnerability mapping can be used to determine the degree of protection (Goldscheider 2010). The purpose of this concept is to identify the most vulnerable areas of the aquifer that need the highest protection and to optimize the land use in the catchment areas of the captured water sources. In many countries, vulnerability mapping is used by law for protection zoning, e.g. in Ireland (for all type of aquifers) and in Switzerland (mainly for karst aquifers). Since protective measures result in land-use restrictions and compensation payments, the vulnerability assessment needs to be reliable (Ravbar & Goldscheider 2009). To avoid subjectivity in vulnerability assessment and to ensure reliable interpretation of vulnerability indices, the validation of vulnerability maps should be done by default. However, until now, validation has not become a standard practice and there is no commonly accepted method. Therefore, common validation procedures need to be developed and applied.
Research aims
Despite the fact that a safe water supply is a very important topic, no single country or scientific institution has so far confronted the above described problem. The proposed project will be the first to address it in a comprehensive manner. Development of holistic and systematic validation procedures to evaluate different vulnerability mapping methods and the resulting maps will be the principle objective of this project. A multi-faceted approach will therefore be taken to consider the suitability of various karst-adapted hydrogeological and modelling research methods for validation purposes. On bases of their critical judgement, common guidelines for vulnerability indices verification will be elaborated. The validation procedure that will follow main concepts of vulnerability, will be developed independently from the map making processes.
Methodology
The study will primarily base on application of a selected groundwater vulnerability assessment method on a classical karst test site in Slovenia. The Slovene PI is an author of the so-called Slovene Approach groundwater vulnerability assessment method. As part of a comprehensive groundwater protection strategy (Zwahlen 2004), the Slovene Approach is a precise, physically based methodology that syntheses the information on flow and transport processes. |
Available data on several parameters significantly influencing the path of the water or a potential contaminant from the surface through the aquifer to the abstraction point is used. Each parameter is classified into defined categories or discrete intervals, which reflects the relative degree of vulnerability to contamination. Vulnerability indexes are classified into three vulnerability categories (Ravbar & Goldscheider 2007). Independently, a method modeling spatiotemporal groundwater recharge, developed by the German PI (Hartmann et al. 2014), will be applied. Spatially distributed information of mean annual recharge patterns of the studied area derived from a GIS-based method (APLIS; Andreo et al. 2008) will be defined and combined with the process‐based karst model that provides spatially lumped but temporally distributed information about recharge. By combining both methods, a spatial reference to the lumped simulations of the process‐based model will be added. In this way, a provision of spatiotemporal information of recharge and subsurface flow dynamics will be provided, which can be used to distinguish fast (vulnerable) and slow (less vulnerable) pathways. Application of both methods will be elaborated with the help of ArcGIS 10.1 software. Gained results will be compared and evaluated, which will serve as a basis for the vulnerability assessment validation processes development. In the proposed project the achievements and experiences of both internationally important centres will be complemented in order to achieve the above described aims that will be the added value of this bilateral cooperation. On bases of knowledge and experiences of both institutions the outcome of the bilateral cooperation will be the complementary improvement of the existing investigation techniques.
Expected results
The goal of the project is to evaluate karst water sources vulnerability assessment by means of semi-distributed modelling. We expect the bilateral cooperation presented here to provide improved scientific insight in the fields of vulnerability assessment and to prepare internationally applicable guidelines for vulnerability indices verification. The project activities and findings will be presented at major national and international conferences and published in scholarly journals. Education and training programmes will be directed above all at young researchers involved in the project. The quantitatively expressed result of the scientific activity would be presented through one doctoral dissertation and the publication of two joint articles from the list of the SCI category. Furthermore, the result of work on this project will represent participation in important strategic international projects addressing the issue of groundwater protection in karst areas.
References
Andreo, B., Vías, J., Durán, J., Jiménez, P., López-Geta, J. & Carrasco, F. (2008). Methodology for groundwater recharge assessment in carbonate aquifers: application to pilot sites in southern Spain. Hydrogeology Journal, 16(5), 911–925.
Ford, D.C. & Williams, P.W. (2007). Karst hydrogeology and geomorphology. Wiley, Chichester.
Goldscheider., N. (2010). Delineation of spring protection zones. In: Kresic N, Stevanovic Z (eds) Groundwater hydrology of springs. Engineering, Theory, Management and Sustainability. Elsevier Butterworth-Heinemann, Burlington pp 305-338.
Hartmann, A., Mudarra, M., Andreo, B., Marín, A., Wagener, T. & Lange, J. (2014). Modeling spatiotemporal impacts of hydroclimatic extremes on groundwater recharge at a Mediterranean karst aquifer. Water Resources Research, 50(8), 6507-6521.
Ravbar, N., Goldscheider, N., (2007). Proposed methodology of vulnerability and contamination risk mapping for the protection of karst aquifers in Slovenia. Acta Carsologica 36(3), 461–475.
Ravbar, N., Goldscheider, N., (2009). Comparative application of four methods of groundwater vulnerability mapping in a Slovene karst catchment. Hydrogeology Journal, 17,725–733.
Zwahlen, F., (2004). Vulnerability and Risk Mapping for the Protection of Carbonate (Karstic) Aquifers. Final report COST action 620. European Commission, Directorate-General for Research, Brüssel, Luxemburg.
The goal of the project is to evaluate karst water sources vulnerability assessment by means of semi-distributed modelling. We expect the bilateral cooperation presented here to provide improved scientific insight in the fields of vulnerability assessment and to prepare internationally applicable guidelines for vulnerability indices verification. The project activities and findings will be presented at major national and international conferences and published in scholarly journals. Education and training programmes will be directed above all at young researchers involved in the project. The quantitatively expressed result of the scientific activity would be presented through one doctoral dissertation and the publication of two joint articles from the list of the SCI category. Furthermore, the result of work on this project will represent participation in important strategic international projects addressing the issue of groundwater protection in karst areas.
References
Andreo, B., Vías, J., Durán, J., Jiménez, P., López-Geta, J. & Carrasco, F. (2008). Methodology for groundwater recharge assessment in carbonate aquifers: application to pilot sites in southern Spain. Hydrogeology Journal, 16(5), 911–925.
Ford, D.C. & Williams, P.W. (2007). Karst hydrogeology and geomorphology. Wiley, Chichester.
Goldscheider., N. (2010). Delineation of spring protection zones. In: Kresic N, Stevanovic Z (eds) Groundwater hydrology of springs. Engineering, Theory, Management and Sustainability. Elsevier Butterworth-Heinemann, Burlington pp 305-338.
Hartmann, A., Mudarra, M., Andreo, B., Marín, A., Wagener, T. & Lange, J. (2014). Modeling spatiotemporal impacts of hydroclimatic extremes on groundwater recharge at a Mediterranean karst aquifer. Water Resources Research, 50(8), 6507-6521.
Ravbar, N., Goldscheider, N., (2007). Proposed methodology of vulnerability and contamination risk mapping for the protection of karst aquifers in Slovenia. Acta Carsologica 36(3), 461–475.
Ravbar, N., Goldscheider, N., (2009). Comparative application of four methods of groundwater vulnerability mapping in a Slovene karst catchment. Hydrogeology Journal, 17,725–733.
Zwahlen, F., (2004). Vulnerability and Risk Mapping for the Protection of Carbonate (Karstic) Aquifers. Final report COST action 620. European Commission, Directorate-General for Research, Brüssel, Luxemburg.