Wolfgang Dreybrodt, Franci Gabrovsek, Douchko Romanov
PROCESSES OF SPELEOGENESIS: A MODELING APPROACH

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.

2005, 376 pp., 250 figures, 8 tables, 170 × 240 mm, paperback, ISBN 961-6500-91-0.
zapriAbout author

Wolfgang Dreybrodt, born in 1939, is a professor of experimental physics at the University of Bremen, Germany. He worked in solid state physics and molecular biophysics, and in parallel to this, theoretically and experimentally on the dissolution kinetics of limestone and gypsum. These results enabled to model the evolution of limestone caves, which has been a major focus of his research since 1988. He is author of the book “Processes in Karst Systems – Physics, Chemistry, and Geology” published by Springer in 1988, and co-editor of “Speleogenesis : Evolution of Karst Aquifers” published in 2002 by National Speleological Society, USA. He is an Editor-in-chief of the on-line journal www.speleogenesis.info. Caving, to him means inspiration of his scientific work.

Franci Gabrovsek, born in 1968, graduated in physics at the University of Ljubljana in 1995 and finished a PhD at the Institute of Experimental Physics, University of Bremen in 2000. Since then he has been a research fellow at the Karst Research Institute ZRC SAZU. His main interest is numerical modelling of different karst processes. He is a lecturer in karstology at Nova Gorica Polytechnics and co-editor of Acta Carsologica. He has actively explored caves and karst in China, Brazil and particularly in Slovenia.

Douchko Romanov, born in 1971, graduated in physics at the University of Sofia, Bulgaria in 1998, and finished his PhD at the Institute of Experimental Physics, University of Bremen, Germany, in 2003. Since then he has been a postdoctoral research fellow at the Karst Processes Research Group at the University of Bremen. At present he is involved in modeling the evolution of porosity in porous rock of carbonate platforms and islands.
Contents

FOREWORD (Derek Ford)

PREFACE

1. INTRODUCTION
1.1 Karst: understanding it and the aim of this work
1.2 A karst aquifer and its properties
1.3 Conceptual models of cave development in karst aquifers
1.4 Models derived from basic principles of physics and chemistry
1.5 The concept of this work and the philosophy behind it

2. EQUILIBRIUM CHEMISTRY AND DISSOLUTION KINETICS OF LIMESTONE IN H2O-CO2 SOLUTIONS
2.1 Equilibrium chemistry of H2O-CO2–CaCO3 system
2.2 Chemical kinetics of the of H2O-CO2–CaCO3 system

3. THE EVOLUTION OF A SINGLE FRACTURE
3.1 Evolution under constant head conditions: The feedback mechanism and b breakthrough
3.2 The influence of fracture roughness on karstification times
3.3 Evolution of a single fracture with varying lithology
3.4 The influence of subterranean CO2 sources on the initial karstification of a single fracture
3.5 The role of mixing corrosion in early karst evolution
3.6 Evolution of a single fracture with constant recharge

4. MODELING KARST EVOLUTION ON TWO-DIMENSIONAL NETWORKS: CONSTANT HEAD BOUNDARY CONDITIONS
4.1 Modeling domain
4.2 Percolation networks
4.3 Evolution of 2-D percolation networks and breakthrough
4.4 Statistical 2D-networks
4.5 One step closer to reality. The dual-fracture system
4.6 Geochemical boundary conditions
4.7 Mixing corrosion in dual-fracture aquifers
4.8 Mixing corrosion and breakthrough
4.9 Dual-fracture aquifer: Mixing corrosion from differently vegetated areas
4.10 Dual- fracture aquifer: Subterranean input of CO2
4.11 Evolution of dual-fracture aquifers after breakthrough: Integration of conduits
4.12 Concluding remarks

5. UNCONFINED AQUIFERS UNDER VARIOUS BOUNDARY CONDITIONS
5.1 Calculation of the water table and the evolution of an unconfined aquifer
5.2 Scenario A: The evolution of unconfined aquifers under conditions of constant recharge
5.3 Scenario B: A combination of constant recharge and constant head boundary conditions in a dual-fracture aquifer
5.4 Scenario C: Two valleys of different altitude at the margins of the plateau.
5.5 Mixing corrosion in unconfined aquifers
5.6 Evolution of unconfined aquifers under unevenly distributed recharge
5.7 Unconfined aquifers under miscellaneous boundary conditions

6. KARSTIFICATION BELOW DAM SITES
6.1 Basic settings and modeling domain
6.2. Numerical results for scenarios with uniform nets
6.3 Numerical results for scenarios with statistical nets
6.4 Influence of basic hydrological and geochemical parameters on breakthrough time
6.5. Examples of more complex geological settings
6.6. Conclusion

7. CONCLUSION AND FUTURE PERSPECTIVES

8. BIBLIOGRAPHY

GUEST CHAPTER by Sebastian Bauer, Steffen Birk, Rudolf Liedl and Martin Sauter

SIMULATION OF KARST AQUIFER GENESIS USING A DOUBLE PERMEABILITY APPROACH INVESTIGATION FOR CONFINED AND UNCONFINED SETTINGS
1. Introduction
2. Model formulation
3. Influence of exchange flow on early karstification
4. Karst development in confined settings
4.1 Single conduit development
4.2 Conduit network
5. Karst development in unconfined settings
6. Karst development under man made conditions
7. Conclusions

GUEST CHAPTER by Georg Kaufmann

STRUCTURE AND EVOLUTION OF KARST AQUIFERS: A FINITE-ELEMENT NUMERICAL MODELLING APPROACH
1. Introduction
1.1. Aquifer geometry
1.2. Aquifer response
2. Theory
2.1. Dissolution kinetics of CaCO3-CO2-H2O system
2.2. Flow and evolution of single fracture
2.3. Aquifer network
3. Results for flat-lying strata
3.1. Long-term evolution
3.2. Short-term spring response