Groundwater Vulnerability to Pollution Map for Karst Aquifer Protection (Ziria Karst System, Southern Greece)

In recent years vulnerability maps have been used as a tool to highlight the areas with the greatest potential for groundwater pollution based on the hydrogeological conditions and their respective human impacts. Several regions of Greece depend completely or partially on drinking water from karst aquifers; thus, the production of vulnerability maps for such karstic areas is considered essential. In the present study, an assessment of aquifer intrinsic vulnerability has been conducted applying the COP method in the Ziria karst system. The latter is located at the Northeast part of Peloponnese in South Greece and is used as a public resource for drinking water. This method, which has been developed for carbonate (karst) aquifers, uses the properties of the overlying layers above the water table (O factor), the concentration of flow (C factor) and the precipitation regime (P factor) over the aquifer. The COP method considers karstic landforms as factors that decrease the natural protection provided by the overlying layers of a karst aquifer. With the use of GIS tools, vulnerability maps were produced highlighting the different degrees of intrinsic vulnerability in the karst system of Ziria

Characterizing a coastal karst aquifer using an inverse modeling approach: The saline springs of Thau, southern France

A methodological approach using inverse modeling was used to characterize the functioning of the deep and shallow reservoirs of the Thau karst aquifer system. Three springs were monitored at the convergence of rising saline water diluted with shallow groundwater in karst conduits and unmixed shallow groundwater that behaves as confined groundwater. In such a method, impulse responses of flow and fluxes are combined in order to separate hydrographs. The model explains the salinity and hydraulic head variations of the submarine and inland springs. It confirms and improves the conceptual model of this groundwater system in which mixing of saline and subsurface waters occurs. The different forces driving the upward flowing mixed water into the drainage axis and faults were studied in order to elucidate the springs\u27 functioning. A comparative study of spring functioning is proposed, which clearly shows the very high sensitivity of the groundwater system to changes in recharge and discharge conditions

Water vulnerability assessment in karst environments: a new method of defining protection areas using a multi-attribute approach and GIS tools (EPIK method)

Groundwater resources from karst aquifers play a major role in the water supply in karst areas in the world, such as in Switzerland. Defining groundwater protection zones in karst environment is frequently not founded on a solid hydrogeological basis. Protection zones are often inadequate and as a result they may be ineffective. In order to improve this situation, the Federal Office for Environment, Forests and Landscape with the Swiss National Hydrological and Geological Survey contracted the Centre of Hydrogeology of the Neuchâtel University to develop a new groundwater protection-zones strategy in karst environment. This approach is based on the vulnerability mapping of the catchment areas of water supplies provided by springs or boreholes. Vulnerability is here defined as the intrinsic geological and hydrogeological characteristics which determine the sensitivity of groundwater to contamination by human activities. The EPIK method is a multi-attribute method for vulnerability mapping which takes into consideration the specific hydrogeological behaviour of karst aquifers. EPIK is based on a conceptual model of karst hydrological systems, which suggests considering four karst aquifer attributes: (1) Epikarst, (2) Protective cover, (3) Infiltration conditions and (4) Karst network development. Each of these four attributes is subdivided into classes which are mapped over the whole water catchment. The attributes and their classes are then weighted. Attribute maps are overlain in order to obtain a final vulnerability map. From the vulnerability map, the groundwater protection zones are defined precisely. This method was applied at several sites in Switzerland where agriculture contamination problems have frequently occurred. These applications resulted in recommend new boundaries for the karst water supplies protection-zones

Vulnerability Mapping in Karst Areas and Its Uses in Switzerland

A new approach for delineating protection zones in karst regions based upon vulnerability mapping of catchment areas is being developed at the Swiss National Hydrological and Geological Survey. Due to the particular hydrogeological characteristics of karst aquifers, specific protection measures are required. Protection zones in karst delineated on the basis of existing guidelines generally do not take into consideration hydrogeological factors, and therefore provide only limited efficiency. The newly proposed “EPIK” method is based on vulnerability mapping of the catchment area of the source, where various objective vulnerability factors are taken into consideration: epikarst (E), protective cover (P), infiltration conditions (I), and karstic network (K). A field application on the case of Saint-Imier pilot area is presented