PREFACE ........................................................ XI
LIST OF AUTHORS .............................................. XIII
1 Introduction ................................................. 1
Nico Goldscheider, David Drew & Stephen Worthington
1.1 The purpose of this book ................................ 1
1.2 Why karst aquifers require specific investigation
techniques .............................................. 2
1.2.1 Evolution of the aquifer ......................... 2
1.2.2 Spatial heterogeneity ............................ 2
1.2.3 Hydraulic conductivity-scale effect .............. 3
1.2.4 Duality of recharge and infiltration ............. 3
1.2.5 Duality of porosity, flow and storage ............ 4
1.2.6 Temporal variability ............................. 4
1.3 Overview of methods to study karst aquifers ............. 4
1.4 What can go wrong - an example from Walkerton, Canada ... 7
2 The geological and geomorphological framework ................ 9
Nico Goldscheider & Bartolomé Andreo
2.1 Introduction ............................................ 9
2.2 Mineralogy, lithology and stratigraphy ................. 10
2.2.1 Minerals that form karstifiable rocks ........... 10
2.2.2 Karstifiable rocks .............................. 11
2.2.3 Influence of lithology upon karstifiability ..... 12
2.2.4 From lithostratigraphy to hydrostratigraphy ..... 12
2.3 Geological structures .................................. 14
2.3.1 Folds ........................................... 14
2.3.2 Faults .......................................... 15
2.3.3 Joints and bedding planes ....................... 16
2.3.4 Fracturing studies .............................. 18
2.4 Geomorphology .......................................... 18
2.4.1 Classification of karst landforms and
geomorphological mapping ........................ 18
2.4.2 Relations between karst landforms and
hydrogeology .................................... 21
2.5 Summary ................................................ 23
3 Speleological investigations ................................ 25
Pierre-Yves Jeannin, Chris Groves & Philipp Häuselmann
3.1 Introduction ........................................... 25
3.2 Use of cave survey data for hydrogeology ............... 28
3.2.1 Cave mapping .................................... 28
3.2.2 Cave modelling in 3-D ........................... 29
3.2.3 Precise cave positioning and well placements .... 30
3.2.4 Interpretation of cave surveys .................. 32
3.2.5 The position of the expected active conduits
and their characteristics ....................... 34
3.2.6 Cave genesis and identification of phase
development in cave networks .................... 35
3.2.7 Availability of cave data for hydrogeologists ... 36
3.3 Investigation methods specific to the cave
environment ............................................ 36
3.3.1 Analysis of conduit morphology .................. 36
3.3.2 Analysis of cave sediments ...................... 37
3.3.3 Water tracings within caves ..................... 37
3.4 Monitoring waters in caves ............................. 37
3.4.1 Introduction .................................... 37
3.4.2 Characterisation of flow in the infiltration
zone ............................................ 38
3.4.3 Characterisation of transport in the
infiltration zone ............................... 39
3.5 Summary ................................................ 44
4 Hydrological methods ........................................ 45
Chris Groves
4.1 Introduction ........................................... 45
4.2 General hydrologic characteristics of karst aquifer
systems ................................................ 45
4.3 A basic concept: water balances ........................ 47
4.4 Spring hydrographs ..................................... 49
4.5 Precipitation and recharge monitoring .................. 50
4.5.1 Introduction .................................... 50
4.5.2 Manual gages .................................... 51
4.5.3 Automatic-recording precipitation gages ......... 51
4.5.4 Doppler radar ................................... 52
4.6 Water flow measurement ................................. 52
4.6.1 Introduction .................................... 52
4.6.2 Stage height measurement ........................ 53
4.6.3 Direct discharge measurement .................... 54
4.6.4 Current meters .................................. 54
4.6.5 Weirs and flumes ................................ 57
4.6.6 Tracer dilution ................................. 58
4.6.7 Non-contact methods ............................. 60
4.6.8 Measurement of cave drips ....................... 61
4.7 Electronic data logging ................................ 61
4.8 Summary ................................................ 64
5 Hydraulic methods ........................................... 65
Neven Kresic
5.1 Introduction ........................................... 65
5.2 Hydraulic and hydrogeologic parameters ................. 65
5.2.1 Porosity, effective porosity and storage
capacity ........................................ 65
5.2.2 Hydraulic head .................................. 67
5.2.3 Transmissivity and hydraulic conductivity ....... 69
5.2.4 Groundwater velocity ............................ 70
5.2.5 Groundwater flow ................................ 71
5.3 Hydraulic borehole tests ............................... 75
5.3.1 Introduction .................................... 75
5.3.2 Packer tests .................................... 75
5.3.3 Slug tests ...................................... 78
5.4 Aquifer pumping tests .................................. 80
5.4.1 Introduction .................................... 80
5.4.2 Data analysis ................................... 81
5.4.3 Aquifer anisotropy .............................. 89
5.4.4 Transmissivity of discrete aquifer zones ........ 90
5.5 Summary ................................................ 91
6 Hydrochemical methods ....................................... 93
Daniel Hunkeler & Jacques Mudry
6.1 Introduction ........................................... 93
6.2 Parameters and processes ............................... 93
6.2.1 Generalities .................................... 93
6.2.2 Precipitation-related parameters ................ 94
6.2.3 Soil-related parameters ......................... 95
6.2.4 Carbonate-rock related parameters ............... 97
6.2.5 Parameters related to other rock-types .......... 98
6.2.6 Compounds of anthropogenic origin ............... 99
6.3 Sampling strategies and methods ....................... 102
6.3.1 Spatial versus temporal sampling ............... 102
6.3.2 Sampling locations ............................. 102
6.3.3 Sampling frequency ............................. 103
6.3.4 Sampling methods ............................... 103
6.4 Analytical methods .................................... 106
6.4.1 Methods for continuous measurement ............. 106
6.4.2 Laboratory methods ............................. 106
6.5 Interpretation of hydrochemical data .................. 108
6.5.1 Introduction ................................... 108
6.5.2 Assessing aquifer functioning using
parameters related to limestone dissolution .... 108
6.5.3 Assessing residence time and origin of water ... 112
6.5.4 Identifying lateral inflows .................... 114
6.5.5 Demonstrating and quantifying mixing ........... 115
6.5.6 Global analysis using statistical methods ...... 116
6.6 Evaluation of the origin and fate of contaminants ..... 117
6.6.1 Detecting contaminants at karst springs ........ 117
6.6.2 Quantifying contaminant levels ................. 119
6.6.3 Identifying contaminant sources ................ 120
6.6.4 Investigating contaminant fate ................. 121
6.7 Summary ............................................... 121
7 Isotopic methods ........................................... 123
Robert Criss, Lee Davisson, Heinz. Surbeck & William
Winston
7.1 Introduction .......................................... 123
7.2 Hydrogen, carbon and oxygen isotopes .................. 124
7.2.1 Isotope abundance and significance to karst
hydrogeology ................................... 124
7.2.2 Isotopic variations and notation ............... 124
7.3 Oxygen and hydrogen isotopes in meteoric waters ....... 126
7.3.1 Geographic variations .......................... 126
7.3.2 Temporal variations ............................ 126
7.3.3 Meteoric water line ............................ 127
7.4 Source identification of karst water .................. 127
7.4.1 Meteoric percentage of karst waters ............ 127
7.4.2 Isotopic mixing and solute correlations ........ 129
7.4.3 Stable isotope tracing of karst springs ........ 130
7.4.4 Contribution of karst waters to surface
streams ........................................ 131
7.5 Oxygen isotope residence time of karst aquifers ....... 132
7.5.1 Temporal isotopic variations in springs ........ 132
7.5.2 Relative magnitudes of isotopic, physical and
chemical variations ............................ 133
7.5.3 Linear reservoir model ......................... 133
7.5.4 Нуdrologic pulse model ......................... 134
7.6 Radioisotope determination of water age ............... 136
7.6.1 Tritium ........................................ 137
7.6.2 Tritium-helium-3 and krypton-85 ................ 138
7.6.3 Radiocarbon techniques ......................... 139
7.6.4 Radon gas techniques ........................... 141
7.7 Summary ............................................... 144
8 Tracer techniques .......................................... 147
Ralf Benischke, Nico Goldscheider & Christopher Smart
8.1 Introduction .......................................... 147
8.2 Types of artificial tracers ........................... 148
8.2.1 Overview ....................................... 148
8.2.2 Fluorescent dyes ............................... 148
8.2.3 Salts .......................................... 151
8.2.4 Particulate tracers ............................ 152
8.3 Preparation and operation of tracer tests ............. 153
8.3.1 Preliminary investigations and legal aspects ... 153
8.3.2 Selection of the tracer type and injection
quantity ....................................... 153
8.3.3 Selection of the injection points and
injection techniques ........................... 155
8.3.4 Selection of the sampling sites and sampling
techniques ..................................... 156
8.3.5 Laboratory analyses ............................ 158
8.3.6 Instruments for field measurement .............. 161
8.4 Evaluation and interpretation ......................... 162
8.4.1 Data requirements, data quality and error
analysis ....................................... 162
8.4.2 Tracer background .............................. 163
8.4.3 Tracer transport in groundwater ................ 164
8.4.4 Breakthrough curves ............................ 165
8.4.5 Travel time and transport velocity ............. 166
8.4.6 Mass recovery .................................. 166
8.4.7 Characterisation of conduit networks ........... 167
8.4.8 Quantification of transport parameters using
analytical models .............................. 169
8.5 Summary ............................................... 170
9 Geophysical methods ........................................ 171
Timothy D. Bechtel, Frank P. Bosch & Marcus Gurk
9.1 Introduction .......................................... 171
9.2 General considerations in geophysics .................. 171
9.2.1 Why use geophysics? ............................ 171
9.2.2 Prerequisites for subsurface detection ......... 175
9.2.3 The noise problem .............................. 176
9.2.4 Resolution versus depth of investigation ....... 176
9.2.5 Technique selection ............................ 176
9.2.6 Location control ............................... 177
9.2.7 Non-uniqueness ................................. 177
9.3 Seismic methods ....................................... 177
9.3.1 Background ..................................... 177
9.3.2 Seismic refraction ............................. 179
9.3.3 Seismic reflection ............................. 180
9.3.4 Surface wave analysis .......................... 181
9.4 Gravity methods ....................................... 181
9.5 Electrical and electromagnetic methods ................ 183
9.5.1 Background ..................................... 183
9.5.2 DC electrical methods .......................... 183
9.5.3 AC electromagnetic methods ..................... 185
9.5.4 Spontaneous potential .......................... 191
9.5.5 Ground penetrating radar (GPR) ................. 192
9.5.6 Magnetic methods ............................... 194
9.6 Borehole geophysical logging .......................... 194
9.7 Summary ............................................... 199
10 Modelling karst hydrodynamics .............................. 201
Attila Kovács & Martin Sauter
10.1 Introduction .......................................... 201
10.2 Conceptual models of karst systems .................... 202
10.3 Modelling approaches .................................. 202
10.4 Global models ......................................... 203
10.4.1 Introduction ................................... 203
10.4.2 Single event models (grey box models) .......... 204
10.4.3 Time series analysis ........................... 207
10.5 Distributive models ................................... 208
10.5.1 Introduction ................................... 208
10.5.2 Discrete Fracture Network Approach (DFN) ....... 210
10.5.3 Discrete Conduit Network Approach (DCN) ........ 212
10.5.4 Equivalent Porous Medium Approach (EPM) ........ 213
10.5.5 Double Continuum Approach (DC) ................. 214
10.5.6 Combined Discrete-Continuum (hybrid) Approach
(CDC) .......................................... 216
10.6 Modelling solute and heat transport in karst
aquifers .............................................. 218
10.7 Summary ............................................... 220
11 Combined use of methods .................................... 223
David Drew & Nico Goldscheider
11.1 Introduction and summary of methods ................... 223
11.2 Combined methods for specific investigations .......... 224
11.2.1 Determining the catchment areas for springs .... 224
11.2.2 Locating water sources ......................... 227
11.2.3 Assessing water quality and contamination
problems ....................................... 227
11.2.4 Conceptualising karst flow systems ............. 228
11.2.5 Assessing groundwater vulnerability in karst
areas .......................................... 228
References .................................................... 229
Index ......................................................... 263
|
