Infiltration Measurements for Soil Hydraulic Characterization (eBook)

Foreword 8
Contents 10
Chapter 1: An Introduction to Soil and Water Infiltration 13
1.1 General Characteristics of Soil 13
1.2 Soil Water Content and Potential 21
1.3 Flow of Water in Soils 27
1.4 Infiltration Process and Equations 36
1.4.1 Gravity Free Water Absorption 38
1.4.2 Green and Ampt Model for Infiltration 40
1.4.3 Philip Equation for Capillary and Gravity Driven Infiltration 41
1.4.4 Sorptivity and Flux Concentration Function 43
1.4.5 General Infiltration Solution of Parlange 44
1.4.6 Extension to 3D Water Infiltration Below a Disk Source 48
References 51
Chapter 2: Saturated Soil Hydraulic Conductivity 55
2.1 Well or Borehole Permeameters 55
2.1.1 Steady Flow Under Constant Head in Uncased Boreholes 56
2.1.1.1 Description of the Method 56
2.1.1.2 Calculation of Soil Parameters 61
2.1.1.3 Issues of Practical Interest 67
2.1.2 Steady Flow Under Constant Head in Cased Boreholes 86
2.1.2.1 Configurations and Principles 86
2.1.2.2 Modelling Flow Out of the Borehole 87
2.1.2.3 Estimation of Kfs and phim from Experimental Flow Rate 88
2.1.2.4 Validation of Methods with Numerically Generated Data 90
2.1.2.5 Drive Point Guelph Permeameter 90
2.1.3 Transient Flow Under Constant Head in Cased and Uncased Boreholes 93
2.1.4 Falling-Head Flow in Cased Boreholes 97
2.1.4.1 Principles 97
2.1.4.2 Analytical Modeling of Water Drop 98
2.1.4.3 Procedure to Derive Kfs and C 100
2.1.4.4 Alternative Mathematical Methods 103
2.1.4.5 Practical Issues and Comparison with Other Experimental Methods 104
2.1.4.6 Alternative Setups and Mathematical Methods for Falling-Head Flow in Cased Boreholes 105
2.2 Ring Infiltrometers 109
2.2.1 Single-Ring Pressure Infiltrometer 109
2.2.1.1 A Review of Devices and Apparatus 109
2.2.1.2 Physics of Flow Under the Single-Ring Pressure Infiltrometer 114
2.2.1.3 Analysis of Steady-State Flow 116
2.2.1.4 Analysis of Transient Flow 120
2.2.1.5 Validation and Use of the Single-Ring Pressure Infiltrometer 123
2.2.1.6 Issues of Practical Interest 127
2.2.2 Other Single-Ring Approaches 141
2.2.2.1 The Beerkan Experimental Protocol 141
2.2.2.2 The Method by Touma et al. (2007) 142
2.2.2.3 The Simplified Method Based on the Beerkan Infiltration Run 143
2.2.2.4 Steady-State Falling-Head Method 152
2.2.2.5 Bottomless Bucket Method 153
2.2.3 Double-Ring Infiltrometer 157
2.2.3.1 Description and Operation of the Double-Ring Infiltrometer 157
2.2.3.2 Calculation of Soil Parameters 158
2.2.3.3 Influence of Setup Design on DRI Results 161
2.2.3.4 Sources of Errors in the DRI Results 162
2.2.4 Simplified Falling Head Technique 163
2.2.4.1 Principles and Application of the Technique 163
2.2.4.2 Issues of Practical Interest 168
2.2.4.3 Comparison with Other Infiltration Techniques 174
2.2.4.4 Two-Level Analysis 176
2.3 Dripper or Point-Source Method 179
References 181
Chapter 3: Unsaturated Soil Hydraulic Properties 193
3.1 Tension or Disk Infiltrometer 193
3.1.1 Basis of the Technique 193
3.1.2 Apparatus and Procedures 195
3.1.3 Analysis of Steady-State Flow 205
3.1.4 Analysis of Transient Flow 218
3.1.5 Numerical Inversion of Tension Disk Infiltrometer Data 230
3.1.6 Particular Devices 235
3.1.7 Hydraulic Contact at the Infiltration Surface 245
3.1.8 Applying the Tension Infiltrometer on Sloping Land 256
3.2 BEST - Beerkan Estimation of Soil Transfer Parameters Procedure 258
3.2.1 Soil Hydraulic Characteristic Curves 258
3.2.2 Soil Particle-Size Distribution, Bulk Density and Water Content 259
3.2.3 Water Infiltration Experiments 260
3.2.4 Estimating Shape Parameters by Inverting Particle-Size Distribution Data 262
3.2.5 Estimating Scale Parameters by Inverting Water Infiltration Data 265
3.2.6 Issues on Estimation of Shape Parameters 271
3.2.7 Issues on Estimation of Scale Parameters 275
3.2.8 Tests of the Soil Hydraulic Characteristic Curves 280
3.2.9 Using the Soil Hydraulic Parameters Obtained with BEST 280
References 291
Chapter 4: Soils with Specific Features 300
4.1 Water Repellent Soils 300
4.1.1 Causes of Hydrophobicity 300
4.1.2 Hydrophobicity and Water Infiltration 302
4.1.3 Hydraulic Characterization of Water Repellent Soils 305
4.2 Crusted Soils 312
4.2.1 Crust Formation 313
4.2.2 Water Infiltration Experiments for Crust Characterization 314
4.3 Low Permeability Soils 324
4.3.1 Early-Time Constant-Head (ECH) Technique 325
4.3.2 Early-Time Falling-Head (EFH) Technique 329
4.3.3 Sequential Early-Time Constant-Head/Falling-Head (ECFH) Technique 332
4.3.4 Saturated Conductivity of Low Permeability Wet Soils 333
4.3.5 Time Domains for Pressure Infiltrometer Data 334
4.3.6 Accounting for Soil Swelling 335
4.4 Macroporous and Bi-modal Soils 337
4.4.1 Conceptual Models for Preferential Flow 338
4.4.2 Modelling Water Infiltration into Dual Permeability Soils 342
4.4.3 How to Detect Preferential Flow 345
4.4.4 How to Characterize Dual Permeability Soils 349
References 357
Chapter 5: Appendix - Additional Measurements 366
5.1 Soil Bulk Density 366
5.2 Soil Water Content 372
5.3 Soil Water Matric Potential 378
5.4 Soil Water Retention Curve 382
5.5 Water Stability of Soil Aggregates 384
References 391
Index 395