Infiltration Theory for Hydrologic Applications

Published by the American Geophysical Union as part of the Water Resources Monograph Series, Volume 15.

Here is your state-of-the-art guidebook through soil infiltration theory in response to hydrologic problems. By focusing on the theoretical basis of physically based infiltration functions and their application, Infiltration Theory for Hydrologic Applications presents an in-depth review of current issues and concerns. For scientists wishing concise and robust equations that can be applied in models for a variety of objectives.

Preface vii

1. Introduction 1

Brief History 1

Runoff Mechanisms 3

Engineering and Scientific Approaches to Hydrology 4

Objective and Scope of this Work 5

2. Basic Porous Media Hydraulics 7

Capillary Properties of Soil Water 7

Porous Media 9

Darcy's Law 12

Hydraulic Characteristics of Porous Media 13

Steady Flow Soil Water Relations 14

Functional Representation of Hydraulic Characteristics 18

3. Some Essentials of One-Dimensional Porous Media Dynamics 25

Introduction 25

Absorption: Gravity-Free Intake 27

Infiltration: Vertical Flow 31

Mathematical Approximations for Soil Water Flow 34

Approximations for Soil Hydraulic Characteristics 36

4. A Realistic Integrable Nonlinear Model for Transient Unsaturated Flow 41

Introduction 41

Integrable Forms of Richards' Equation' 43

Solution of Nonlinear Diffusion Equation 46

Required Forms for Soil Characteristics 49

Solution of the Integrable Form 55

Discussion and Summary 60

5. Absorption and Infiltration Relations and the Infiltrability-Depth

Approximation 63

Introduction 63

Absorption 65

Infiltration 73

Stability of Flux-ConcentrationR elation 85

6. Infiltrability Models: Comparisons and Application 97

Introduction 97

Timing of Pending 98

Time Explicit Approximations 108

Applying the Infiltrability Models to Variable Rainfall Patterns 114

7. Applying Infiltration Models in Layered Soils and Redistribution Cases 119

Introduction 119

Redistribution and Reinfiltration 119

Layered Soils 122

8. Field Measurements of Infiltration Parameters 135

Introduction 135

Drip Infiltrometers 136

Ring Infiltrometers 138

Permeameters 141

9. Infiltration and Runoff on a Hillslope 159

Introduction 159

General Surface Flow and Infiltration Interaction 160

Effect of Surface Relief on Surface Water Losses 162

Infiltration Heterogeneity and Runoff 164

Appendices 185

I. Derivation of the Infiltration Integral from Richards' Equation 185

II. Attenuation of Characteristic Kinematic Shock in Soil Water Flow 187

III. Finite Difference Solution Method for Richards' Equation 190

List of Symbols and Abbreviations 199

References 203

Index 211

Roger E. Smith and Keith R. J. Smettem are the authors of Infiltration Theory for Hydrologic Applications, published by Wiley.