Karstic groundwater flow characteristics in the Cretaceous Chalk aquifer, Northern Ireland, 1999, Barnes S,

The Cretaceous Chalk in Northern Ireland (Ulster White Limestone Formation) is a locally important aquifer for both public and private supply, yet little is known about its groundwater flow regime. This issue is important for the protection of existing groundwater abstractions and for the development of new sources as it will help determine groundwater vulnerability and resource potential in the Chalk. The subject has been addressed using hydrochemical variations from individual springs, together with artificial and natural water tracing techniques employed from river-sinks located at outcrop. A common orientation has been established between traced groundwater flow routes and the dominant northwest-southeast fracture trend within the Ulster White Limestone Formation. Hydraulic gradient has also been shown to have little significance in controlling the flow direction, suggesting poor fracture connectivity and thus extreme aquifer heterogeneity. Tracer breakthrough curve characteristics and velocities (up to 2838 metres per day) are indicative of conduit rather than fracture flow. In addition, the highly variable water chemistry associated with all the proven river-sink supplied springs has been independently classified to meet conduit flow criteria. Conversely, the much less variable water chemistry associated with springs draining Chalk subcrop areas (with no influence from river-sinks) is consistent with a less active karstic regime

Karst Water Research in Slovenia, 2000, Kranjc, Andrej

About 43% of the territory of Slovenia is karst and more than 50% of its inhabitants are supplied with water from karst. Karst in Slovenia is divided into Dinaric, Alpine and transitional karst. Each of these types bears its own hydrological properties. Already in the antique literature underground water connections are mentioned. Water tracing in the Slovene Karst is among the first modern tracing research. Karst water research may be divided into several periods: (1) aimed at determining underground water connections between swallow-holes and springs (the first half of the 20th century), (2) to achieve combined water tracing tests (since 1970), (3) to define karst watersheds, (4) to study water percolation through the epikarst and the vadose zone (since 1980). In particular, the researches of karst water quality must be emphasised, as well as the study of karst hydrology as a phenomenon in itself. At the end a logical question appears: what are the future perspectives of karst water studies in Slovenia? Water tracing of not yet fully ascertained connections or repeating the water tracing tests under different hydrological conditions; a detailed determination of watersheds and water flow with the help of tracers directly injected underground; to develop water tracing techniques and methods; to study in the field percolation water behaviour; modelling; to theoretically determine physical laws. Special attention must also be paid to education.

Tracer tests in karst hydrogeology and speleology, 2008, Goldscheider N. , Meiman J. , Pronk M And Smart C.

This article presents an introduction to the fundamentals of tracing techniques and their application in cave and karst environments, illustrated by case studies from the Mammoth Cave, USA, and a small experimental site in Switzerland. The properties and limitations of the most important artificial tracers are discussed, and the available methods of tracer injection, sampling, online monitoring and laboratory analysis are presented. Fully quantitative tracer experiments result in continuous or discrete concentration-time data series, i.e. breakthrough curves, and concomitant discharge data, which make it possible to obtain detailed information about groundwater flow and contaminant transport. Within the frame of speleological investigations, tracer tests can help to resolve the active and often inaccessible part of cave and conduit networks and to obtain indications about the geometry and volume of the conduits. For hydrogeological studies, caves can in turn be used as natural experimental and monitoring sites inside the unsaturated or saturated zone of karst aquifer systems.

Tracer tests in karst hydrogeology and speleology, 2008, Goldscheider N. , Meiman J. , Pronk M. , Smart C.

This article presents an introduction to the fundamentals of tracing techniques and their application in cave and karst environments, illustrated by case studies from the Mammoth Cave, USA, and a small experimental site in Switzerland. The properties and limitations of the most important artificial tracers are discussed, and the available methods of tracer injection, sampling, online monitoring and laboratory analysis are presented. Fully quantitative tracer experiments result in continuous or discrete concentration-time data series, i.e. breakthrough curves, and concomitant discharge data, which make it possible to obtain detailed information about groundwater flow and contaminant transport. Within the frame of speleological investigations, tracer tests can help to resolve the active and often inaccessible part of cave and conduit networks and to obtain indications about the geometry and volume of the conduits. For hydrogeological studies, caves can in turn be used as natural experimental and monitoring sites inside the unsaturated or saturated zone of karst aquifer systems.

Chemical and isotopic (d18O%, d2H%, d13C%, 222Rn%) multi-tracing for groundwater conceptual model of carbonate aquifer (Gran Sasso INFN underground laboratory – central Italy), 2008, Adinolfi Falcone R. , Falgiani A. , Parisse B. , Petitta M. , Spizzico M. , Tallini M.

A hydrochemical and isotope study was conducted on the drainage waters of an underground laboratory, located inside the Gran Sasso massif (central Italy). The study was expected to improve the conceptual model of groundwater circulation at the base of an over 1000-thick unsaturated zone in the Gran Sasso partitioned karst aquifer. This lithostratigraphically and tectonically complex aquifer is typical of Africa–Europe thrust-andfold collision belt in the Mediterranean area. In this case, investigations on water–rock interactions during recharge in complex aquifers, overlaid by a thick unsaturated zone, have been made thanks to the strategic location of the Gran Sasso underground laboratories, located in the core of a huge carbonate aquifer. Knowledge of the local basic hydrogeological setting was the starting point for a detailed hydrogeochemical and isotopic study, which was carried out at the aquifer scale and at the fine scale in the underground laboratories. The water–rock interaction processes were investigated both spatially and in temporal sequences, analysing recharge waters and groundwater in the underground laboratories by multitracing techniques, including major ions and d18O&, d2H& and d13C& stable isotopes. Use of 222Rn provides information on transit time in the aquifer. Processes proved to be typical of carbonate rocks, with clear influence of vertical movement of water on chemical–physical parameters through the unsaturated zone. Conversely, in the saturated zone, these processes proved to be dominantly affected by local geological–structural conditions. A conceptual model with dual flow velocity is proposed, directly related to the local geological-structural setting. 222Rn decay enables to calculate an effective velocity of around 10 m/day for the fracture network, through the sequence of less permeable dolomites and underlying limestone. Lag time between recharge and chemical changes in the saturated zone testifies to an effective velocity of about 35 m/day for fast flow through recent and active extensional faults