This book draws together the major recent advances in the modeling of karst systems. Based on the dissolution kinetics of limestone, and flow and transport processes in its fractures, it presents a hierarchy of cave genetic situations that range from the enlargement of a single fracture to the evolution of cavernous drainage patterns in confined and unconfined karst aquifers. These results are also applied to the evolution of leakage below dam sites in karst. The book offers a wealth of informations that help to understand the development of cave systems. It addresses geologists, hydrologists, geomorphologists, and geographers. It is also of interest to all scientists and engineers who have responsibilities for groundwater exploration and management in karst terrains. A CD including all figures figures from the nook and numerous animations presenting the results is enclosed. Knjiga Processes of speleogenessis: a modeling approach (Procesi speleogeneze: modelski pristop) ponuja izčrpen vpogled v procese in dinamiko razvoja kraškega razpoklinskega sistema. Na podlagi numeričnih modelov odgovarja na vprašanja, kako hitro in kje se v različnih pogojih razvijajo kraški kanali ter kateri parametri vplivajo na njihov razvoj. Knjigi je dodana zgoščenka, na kateri so rezultati najbolj tipičnih primerov prikazani v obliki animacij.

In the catchment area of the Unica River two combined tracer tests with fluorescent dyes have been performed aiming to characterize the properties of groundwater flow and transport of contaminants through the vadose zone and well developed system of karst channels in the epiphreatic and phreatic zone in different hydrologic conditions. Tracers were injected directly into the ponors and to the oil collector outlet on the karst surface. Prior to tracing monitoring network has been set up, including precipitation, physical and chemical parameters of the springs and cave streams. Field fluorimeters were used to detect tracers in the underground river and conventional sampling techniques and laboratory analyses were used at the springs. Some of the results were quantitatively evaluated by QTRACER2 Program. During the first tracer test, when injection was followed by rain event, flow through the well conductive cave system was characterized by apparent dominant flow velocities of 88–640 m/h. Breakthrough curves were continuous, uniform and single peaked, and almost complete recoveries were observed. During the second tracer test, when water level was in constant recession, the transport velocities through the well developed karst conduits were significantly slower (apparent maximal flow velocities being 2–4 times lower). Results also show lower dispersivity during the second tracer test, which corresponds to lower flow velocities. The tracer injected at the karst surface arrived with the expected delay (vdom around 9 m/h) and showed irregular and elongated breakthrough curves with secondary peaks. In this paper only tracer test results are presented, which are a part of a comprehensive study of groundwater flow through the complex karst aquifers aiming at improving karst water resources understanding, protection and management. The presented assessment will beyond be utilized for further detailed analysis, studies and modelling.

Understanding the dynamics and distribution of CO₂ in the subsurface atmosphere of carbonate karst massifs provides important insights into dissolution and precipitation processes, the role of karst systems in the global carbon cycle, and the use of speleothems for paleoclimate reconstructions. We discuss long-term microclimatic observations in a passage of Postojna Cave, Slovenia, focusing on high spatial and temporal variations of pCO₂. We show (1) that the airflow through the massif is determined by the combined action of the chimney effect and external winds and (2) that the relationship between the direction of the airflow, the geometry of the airflow pathways, and the position of the observation point explains the observed variations of pCO₂. Namely, in the terminal chamber of the passage, the pCO₂ is low and uniform during updraft, when outside air flows to the site through a system of large open galleries. When the airflow reverses direction to downdraft, the chamber is fed by inlets with diverse flow rates and pCO₂, which enter via small conduits and fractures embedded in a CO₂-rich vadose zone. If the spatial distribution of inlets and outlets produces minimal mixing between low and high pCO₂ inflows, high and persistent gradients in pCO₂ are formed. Such is the case in the chamber, where vertical gradients of up to 1000 ppm/m are observed during downdraft. The results presented in this work provide new insights into the dynamics and composition of the subsurface atmosphere and demonstrate the importance of long-term and spatially distributed observations.

Progress in the understanding of cave genesis processes, as well as the intensive research carried out in the Alps during the last decades, permit to summarize the latest knowledge about Alpine caves. The phreatic parts of cave systems develop close to the karst water table, which depends on the spring position, which in turn is generally related to the valley bottom. Thus, caves are directly linked with the geomorphic evolution of the surface and reflect valley deepening. The sediments deposited in the caves help to reconstruct the morphologic succession and the paleoclimatic evolution. Moreover, they are the only means to date the caves and thus the landscape evolution. Caves appear as soon as there is an emersion of limestone from the sea and a water table gradient. Mesozoic and early tertiary paleokarsts within the alpine range prove of these ancient emersions. Hydrothermal karst seems to be more widespread than previously presumed. This is mostly due to the fact that usually, hydrothermal caves are later reused (and reshaped) by meteoric waters. Rock-ghost weathering is described as a new cave genesis agent. On the contrary, glaciers hinder cave genesis processes and fill caves. They mainly influence cave genesis indirectly by valley deepening and abrasion of the caprock. All present datings suggest that many alpine caves (excluding paleokarst) are of Pliocene or even Miocene age. Progress in dating methods (mainly the recent evolution with cosmogenic nuclides) should permit, in the near future, to date not only Pleistocene, but also Pliocene cave sediments absolutely.

Measurements of radon concentration were performed at three geomorphologically different locations in Postojna Cave, Slovenia. In the part of the cave open to visitors, annual average radon activity concentrations of 3255 ± 1190 Bq m⁻³ and 2315 ± 1019 Bq m⁻³ were found at the lowest point (LP) and in the Lepe jame (Beautiful Caves, BC), respectively. A much higher average of 25 020 ± 12 653 Bq m⁻³ was characteristic of the dead-end passage Pisani rov (Gaily Coloured Corridor, GC), in which CO₂ concentration also reached very high values of 4689 ± 294 ppm in summer. Seasonal variations of radon and CO₂ levels in the cave are governed by convective airflow, controlled mainly by the temperature difference between the cave and the outside atmosphere. The following additional sources of radon and CO₂ were considered: (i) flux of geogas from the Earth's crust through fractured rocks (radon and CO₂ source), (ii) clay sediments inside the passage (radon source) and (iii) the soil layer above the cave (radon and CO₂ source).