Infiltration Measurements for Soil Hydraulic Characterization

This book summarises the main results of many contributions from researchers worldwide who have used the water infiltration process to characterize soil in the field.  Determining soil hydrodynamic properties is essential to interpret and simulate the hydrological processes of economic and environmental interest.  This book can be used as a guide to soil hydraulic characterization and in addition it gives a complete description of the treated techniques, including an outline of the most significant research results, with the main points that still needing development and improvement.

Foreword.- 1 AN INTRODUCTION TO SOIL AND WATER INFILTRATION.- 1.1 General characteristics of soil.-1.2 Soil water content and potential.- 1.3 Flow of water in soils.- 1.4 Infiltration process and equations.- 1.4.1 Gravity free water absorption.- 1.4.2 Green and Ampt model for infiltration.- 1.4.3 Philip infiltration equation for capillary and gravity driven infiltration.- 1.4.4 Sorptivity and flux concentration function
1.4.5 General infiltration solution of Parlange.- 1.4.6 Extension to 3D water infiltration below a disc source.- References.- 2 SATURATED SOIL HYDRAULIC CONDUCTIVITY.- 2.1 Well or borehole permeameters.- 2.1.1 Steady flow under constant head in uncased boreholes.- 2.1.2 Steady flow under constant head in cased boreholes.- 2.1.3 Transient flow under constant head in cased and uncased boreholes.- 2.1.4 Falling-head flow in cased boreholes.- 2.2 Ring infiltrometers.- 2.2.1 Single-ring pressure infiltrometer.- 2.2.2 Other single-ring approaches.- 2.2.3 Double-ring infiltrometer.- 2.2.4 Simplified falling head technique.- 2.3 Dripper or point-source method.- References.- 3 UNSATURATED SOIL HYDRAULIC PROPERTIES.- 3.1 Tension or disk infiltrometer.- 3.1.1 Basis of the technique.- 3.1.2 Apparatus and procedures.- 3.1.3 Analysis of steady-state flow.- 3.1.4 Analysis of transient flow.- 3.1.5 Numerical inversion of tension disk infiltrometer data.- 3.1.6 Particular devices.- 3.1.7 Hydraulic contact at the infiltration surface.- 3.1.8 Applying the tension infiltrometer on sloping land.- 3.2 BEST - Beerkan estimation of soil transfer parameters procedure.- 3.2.1 Soil hydraulic characteristic curves
3.2.2 Soil particle-size distribution, bulk density and water content.- 3.2.3 Water infiltration experiments.- 3.2.4 Estimating shape parameters by inverting particle-size distribution data.- 3.2.5 Estimating scale parameters by inverting water infiltration data.- 3.2.6 Issues on estimation of shape parameters.- 3.2.7 Issues on estimationof scale parameters.- 3.2.8 Tests of the soil hydraulic characteristic curves.- 3.2.9 Using the soil hydraulic parameters obtained with BEST.- References.- 4 SOILS WITH SPECIFIC FEATURES.- 4.1 Water repellent soils.- 4.1.1 Causes of hydrophobicity.- 4.1.2 Hydrophobicity and water infiltration.- 4.1.3 Hydraulic characterization of water repellent soils.- 4.2 Crusted soils.- 4.2.1 Crust formation.- 4.2.2 Water infiltration experiments for crust characterization.- 4.3 Low permeability soils.- 4.3.1 Early-time constant-head (ECH) technique.- 4.3.2 Early-time falling-head (EFH) technique.- 4.3.3 Sequential early-time constant-head/falling-head (ECFH) technique.- 4.3.4 Saturated conductivity of low permeability wet soils.- 4.3.5 Time domains for pressure infiltrometer data.- 4.3.6 Accounting for soil swelling.- 4.4. Macroporous and bi-modal soils.- 4.4.1. Conceptual models for preferential flow.- 4.4.2. Modelling water infiltration into dual permeability soils.- 4.4.3. How to detect preferential flow.- 4.4.4. How to characterize dual permeability soils.- References.- APPENDIX - ADDITIONAL MEASUREMENTS.- A1. Soil bulk density
A2. Soil water content.- A3. Soil water matric potential.- A4. Soil water retention curve.- A5. Water stability of soil aggregates.- References.