Hydrogeology and vulnerability of karst systems - examples from the Northern Alps and the Swabian Alb [online] (original) (raw)
Related papers
Karst morphology and groundwater vulnerability of high alpine karst plateaus
Environmental Earth Sciences, 2009
High alpine karst plateaus are recharge areas for major drinking water resources in the Alps and many other regions. Well-established methods for the vulnerability mapping of groundwater to contamination have not been applied to such areas yet. The paper characterises this karst type and shows that two common vulnerability assessment methods (COP and PI) classify most of the areas with high vulnerability classes. In the test site on the Hochschwab plateau (Northern Calcareous Alps, Austria), overlying layers are mostly absent, not protective or even enhance point recharge, where they have aquiclude character. The COP method classifies 82% of the area as highly or extremely vulnerable. The resulting maps are reasonable, but do not differentiate vulnerabilities to the extent that the results can be used for protective measures. An extension for the upper end of the vulnerability scale is presented that allows identifying ultra vulnerable areas. The proposed enhancement of the conventional approach points out that infiltration conditions are of key importance for vulnerability. The method accounts for karst genetical and hydrologic processes using qualitative and quantitative properties of karst depressions and sinking streams including parameters calculated from digital elevations models. The method is tested on the Hochschwab plateau where 1.7% of the area is delineated as ultra vulnerable. This differentiation could not be reached by the COP and PI methods. The resulting vulnerability map highlights spots of maximum vulnerability and the combination with a hazard map enables protective measures for a manageable area and number of sites.
GROUNDWATER PROTECTION IN KARST ENVIRONMENT
Protection of karstic groundwater quality can be successful only if it is based on reliable reconstructions of conceptual models of the karstic aquifers, which are normally of high complexity: this requires the integration of classical hydrogeological information with that obtainable by using natural tracers, according to multi-tracing methods. The definition of the conceptual model includes elements as the identification of recharge areas, their connection with discharge areas, the sequence of physical -chemical processes acting into the aquifer and the transport mechanisms. With reference to the identification of recharge areas, two casestudies are illustrated. The first deals with a continental karstic aquifer (Monti Simbruini, Central Italy) discharging through springs used for drinking purposes: it has been studied by using the stable deuterium and oxygen-18 isotopes according to the "mass-center" method coupled with the "inverse hydrogeological budget" method. The second regards a platform karstic aquifer (Murgia, Southern Italy), discharging through coastal brackish springs, which is exploited by wells for both drinking and agricultural purposes: for recognizing some elements of the conceptual model a multi-tracing approach has been adopted, which uses the crossverification of information coming from the interpretation of isotopic, chemical and physical tracers. Moreover, with the aim of outlining the factors that control the pollutant transport in karstic aquifers, two case-studies related to Murgia aquifer illustrate a first method for defining the hazard due to direct injection of effluents from treatment plants and a second approach for defining, through monitoring data, the transport mechanisms of pollutant released at land surface.
Environ Earth Sci (2015) 74:227–240 , 2015
Karstic aquifers are the main groundwater source in Southeastern Europe and the Middle East. Many large springs and sources which drain Alpine orogenic belt and its branches are tapped and utilized for drinking water supply. Due to the unstable regime of the karstic springs, the main challenge for most of the waterworks is to ensure water supply during recession periods which coincide with the dry season, usually summer and early autumn months. Besides the problem of water shortage, water pollution of this open and generally very permeable type of aquifer is another major constraint in local water management. However, in comparison with other type of aquifers, the highly developed karst and its significant storage capacity as found in the studied areas may attenuate significant rainfall/runoff variations and possible climate changes. Most commonly, intensive rain episodes do not result in extreme floods in the studied karst terrains, while stored groundwater provides sufficient base flows for dependent ecosystems during the recession or periods of drought. Several typical hydrographs and results of some models applied for forecasting climate change impact presented in this paper represent a good example of specific karst aquifer behaviours and importance of considerable storage capacity in deeper parts of the aquifer. The final publication is available at link.springer.com
Research frontiers and practical challenges in karst hydrogeology
Acta Carsologica, 2010
Besides t�e possible future impacts of climate c�ange, t�ere are many ot�er urgent groundwater-related environmental problems. Accessibility to safe drinking water in sufficient quantities for �uman needs is t�reatened by different types of contamination, overexploitation, saltwater intrusions, and inappropriate irrigation practices. Soil erosion, natural disasters, and t�e protection of ecosystems and biodiversity are ot�er important water-related issues. These problems exist today, but will get worse in many regions according to t�e current climate c�ange scenarios. All of t�ese issues are interrelated and are especially relevant in karst areas. For example, deforestation leads to ecosystem degradation and a loss of biodiversity, but also promotes soil erosion (Fig. 1), w�ic� increases t�e vulnerability of groundwater resources to contamination, alters rec�arge processes and reduces t�e water storage and buffering capacity of t�e �ydrogeologic system, t�us posing a t�reat to quality and quantity of drinking water and ultimately to public �ealt�. Furt�ermore, t�e degradation of soil and vegetation also releases CO 2 and reduces t�e efficiency of karst processes as a natural sink of t�is green�ouse gas (Liu & Z�ao 2000). Finding solutions to all of t�ese problems requires a multidisciplinary approac�, to w�ic� karst and groundwater researc�ers could and s�ould contribute more t�an t�ey currently do.
The vulnerability of complex karst hydrostructures: Problems and perspectives3
2004
In the last 15 years some large karst aquifers of Italy were studied to realize maps of intrinsic and integrated vulnerability to pollution on the basis of the point count system model SINTACS. The most important characteristics are: the heterogeneity levels of the drainage networks; the level of karst evolution both on the surface and deep into the aquifer; the
Role of karstification and rainfall in the behavior of a heterogeneous karst system
Environmental Geology, 1997
The complex functioning of karst systems depends on several factors (e.g., geology, karstification status, climate) which influence flow conditions. Understanding a system requires monitoring that includes a sampling interval well adapted to the system's size, and the use of hydrodynamic and geochemical approaches. From our own observations, the general physical and geochemical characteristics of the aquifers are perennial and representative of karst evolution at a given moment. The Notre-Dame-des-Anges karst system, which is situated in France on the rim of the Vaucluse karst region, was studied during 2 water years. This study demonstrates that several parameters are not definitive, and that they do not provide information about the actual status of the karst evolution of the system. We were able to observe that hydrological parameters in particular are dependent on the configuration of the outlets, which can dramatically change. For example, a heavy storm (300 mm of rain in 4 h), which occurred in the intake area on 22 September 1992, produced a piston effect in the aquifer, which was expressed by extensive unclogging of the whole aquifer. The appearance of a new gryphon at the outlet induced a change in the flow rate and added to the unclogging. The other major result of this study is the demonstration of intensive, even preponderant, participation of water originating in the infiltration zone in the behavior of the system. This contribution, often minimized in previous studies, is closely dependent upon flow conditions and especially upon the recharge status of the infiltration zone. Physical and chemical parameters allowed us to trace this water, and to demonstrate the existence of an actual hanging reserve which plays not a negligible part in flow, during both high and low water levels. This paper demonstrates the necessity of coupling a hydrodynamic study with a hydrochemical approach, and of questioning the representativeness of parameters during a given period, for a better understanding of the functioning of the karst system. This is especially true if the infiltration zone of the karst system is heavily developed, and if external factors (e.g., river, landslip, clogging) influence the outlet
Papers prepared by the authors after reviewing by the members of the scientific committee. Despite this, the scientific board wishes to make clear that it shall take no responsibility for any mistakes, any omissions, or for the opinions stated by the authors. ISBN: 978-2-7466-3694-1 9 th conference on limestone hydrogeology, 2011, Besançon, France V Sessions 9 th conference on limestone hydrogeology 9 ème colloque d'hydrogéologie en pays calcaire Session 1: Groundwater flow and storage in karst aquifers Écoulement souterrain et stockage d'eau dans le karst
The Kanin massif is an important trans-boundary aquifer, which stretches between Slovenia and Italy. The groundwater is only partially exploited, mainly for water supply, but the aquifer exhibits great potential for future exploitation. Since no consistent regional overview of the hydrogeological functioning of the Kanin massif was available, the decision was made to perform a study of this area, using a pragmatic approach based on 3D geological and hydrogeological modelling. The so-called KARSYS approach was applied, with the aim of characterizing the groundwater reserves within this karst massif and of locating the main drainage axes that carry groundwater from the recharge areas to the respective springs. Delineation of the catchment areas of the corresponding springs was carried out, and some new explanations were obtained, especially with regard to the Možnica spring, which is located in Slovenia and forms a potential source of drinking water. It was found that this spring’s catchment area extends as far as the Italian ski resort of Sella Nevea. The conceptual model also provides a possible explanation about the underground drainage towards the Boka spring and waterfall, which has been a challenge for decades. This new explanation is based on the existence of a perched groundwater body that feeds the Boka spring via a system of conduits. Despite some limitations, the results, which consist of a visualization of the underground drainage and groundwater storage within the Kanin massif, can be used as a basis for planning the sustainable management of karst waters in the studied area.
Karst groundwater: a challenge for new resources
Hydrogeology Journal, 2005
Karst aquifers have complex and original characteristics which make them very different from other aquifers: high heterogeneity created and organised by groundwater flow; large voids, high flow velocities up to several hundreds of m/h, high flow rate springs up to some tens of m 3 /s. Different conceptual models, known from the literature, attempt to take into account all these particularities. The study methods used in classical hydrogeology-bore hole, pumping test and distributed models-are generally invalid and unsuccessful in karst aquifers, because the results cannot be extended to the whole aquifer nor to some parts, as is done in non-karst aquifers. Presently, karst hydrogeologists use a specific investigation methodology (described here), which is comparable to that used in surface hydrology. Important points remain unsolved. Some of them are related to fundamental aspects such as the void structureonly a conduit network, or a conduit network plus a porous matrix-, the functioning-threshold effects and nonlinearities-, the modeling of the functioning-double or triple porosity, or viscous flow in conduits-and of karst genesis. Some other points deal with practical aspects, such as the assessment of aquifer storage capacity or vulnerability, or the prediction of the location of highly productive zones.