Infiltration theory for hydrologic applications / Roger E. Smith ; with Keith R.J. Smettem, Philip Broadbridge and D.A. Woolhiser.
By: Smith, Roger Elton.
Contributor(s): Smettem, Keith R. J | Broadbridge, Philip | Woolhiser, D. A | American Geophysical Union.
Material type: BookSeries: Water resources monograph: 15Publisher: Washington, DC. : American Geophysical Union, ©2002Description: viii, 212 pages : illustrations ; 23 cm.ISBN: 0875903193 (pbk.); 9780875903194 (pbk.).Subject(s): INFILTRATION | HYDROLOGICAL METHODS | THEORIES | GROUNDWATER FLOW | SEEPAGE | PERCOLATIONHoldings: GRETA POINT: 631.432.3 SMIItem type | Current library | Call number | Copy number | Status | Date due | Barcode | |
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BOOK | WELLINGTON BOOKS | 631.432.3 SMI | 1 | Available | B020855 |
Includes bibliographical references (pages 203-210) and index.
Preface -- 1. INTRODUCTION -- Brief History -- Runoff Mechanisms -- Engineering and Scientific Approaches to Hydrology -- Objective and Scope of this Work -- 2. BASIC POROUS MEDIA HYDRAULICS -- Capillary Properties of Soil Water -- Porous Media -- Darcy’s Law -- Hydraulic Characteristics of Porous Media -- Scaled Hydraulic Characteristics -- Steady Flow Soil Water Relations -- Functional Representation of Hydraulic Characteristics -- Soil Water Retention -- Unsaturated Hydraulic Conductivity -- A Generalized Formulation -- Summary -- 3. SOME ESSENTIALS OF ONE-DIMENSIONAL POROUS MEDIA DYNAMICS -- Introduction -- Definition -- Assumptions -- Absorption: Gravity-Free Intake -- Absorption with a Constant Head Boundary -- Absorption with a Constant Flux Boundary -- Infiltration: Vertical Flow -- Philip’s Series Solution -- Large-Time Solution -- Short Time Solution -- Analytic Solution -- Mathematical Approximations for Soil Water Flow -- Approximations to Equation (3.15) -- Burgers’s Equation Approximation -- Kinematic Wave Approximation -- Approximations for Soil Hydraulic Characteristics -- Delta-Function Diffusivity -- Exponential K (Y) -- The Analytic Solution Soils -- Summary -- 4. A REALISTIC INTEGRABLE NONLINEAR MODEL FOR TRANSIENT UNSATURATED FLOW -- Introduction -- Integrable Forms of Richards’ Equation -- Burgers Equation -- Solution of Nonlinear Diffusion Equation -- Required Forms for Soil Characteristics -- Solution of the Integrable Form -- Time to Ponding -- Discussion and Summary -- 5. ABSORPTION AND INFILTRATION RELATIONS AND THE INFILTRABILITY-DEPTH APPROXIMATION -- Introduction -- Mass Balance Across the Intake Boundary -- Absorption -- The Flux-Concentration Relation -- The Capillary Length Scale -- The Infiltrability-Depth Approximation: IDA -- Infiltration -- Time Series Solution of Philip -- Approximate Integration of the Infiltration Integral -- Describing Surface Water Content Evolution Under Rainfall -- Treatment of Surface Water Depth -- Stability of Flux-Concentration Relation -- Soil Types Evaluated -- F (Oi) Under Absorption-- F (O) Under Infiltration -- Implications of F (O) Observations -- Summary -- 6. INFILTRABILITY MODELS: COMPARISONS AND APPLICATION -- Introduction -- Scaling Parameters -- Timing of Ponding -- Three Approximate Forms -- The Broadbridge-White Soil -- Other Forms of the Infiltrability Relations -- Normalizing the Infiltrability Functions -- Time Explicit Approximations -- Applying the Infiltrability Models to Variable Rainfall Patterns -- Summary -- 7. APPLYING INFILTRATION MODELS IN LAYERED SOILS AND REDISTRIBUTION CASES -- Introduction -- Redistribution and Reinfiltration -- Redistribution of Water During Rainfall Hiatus -- Reinfiltration Calculations -- Layered Soils -- Assymptotic fc for General Layered Case -- A Single Restrictive Upper Layer -- Infiltration and Redistribution/Reinfiltration in Layered Soils -- Summary -- 8. FIELD MEASUREMENTS OF INFILTRATION PARAMETERS -- Introduction -- Drip Infiltrometers -- Ring Infiltrometers -- Permeameters -- Determining Infiltration Parameters by Monitoring Flow from a Shallow Circular Pond -- Surface Disk Tension Infiltrometers: Steady-State Solutions -- Surface Disk Tension Infiltrometers: Transient Solutions -- A Field Example of Tension Infiltrometer Data Analysis -- Surface Disk Tension Infiltrometers: Numerical Investigation of an Illustrative Layered Profile -- Concluding Remarks -- 9. INFILTRATION AND RUNOFF ON A HILLSLOPE -- Introduction -- General Surface Flow and Infiltration Interaction -- Effect of Surface Relief on Surface Water Losses -- Infiltration Heterogeneity and Runoff -- Deterministic Variation in Infiltration Rates -- Random Special Variation in Infiltration Rates -- Infiltration and “Runon” Effects -- Summary -- APPENDICES -- I. Derivation of the Infiltration Integral from Richards’ Equation -- II. Attenuation of Characteristic Kinematic Shock in Soil Water Flow -- III. Finite Difference Solution Method for Richards’ Equation -- List of Symbols and Abbreviations -- References -- Index.
Many recent books on soil physics provide a good coverage of unsaturated soil water flow from the perspective of water movement within soil. But those texts rarely deal with those parts of porous media hydraulics which inform a scientific approach to infiltration for hydrology, which is focused on the intake and movement of water at the boundary. Recent textbooks on hydrology, on the other hand, mostly continue to treat infiltration by typically reviewing the concepts of Green and Ampt, and listing one or more popular algebraic formulas (with parameters of limited physical significance which are 50 or more years old. The concepts which link soil physics and hydrology and unify our understanding of infiltration from both rainfall and from irrigation conditions are usually not yet being presented as a unified body, but remain separately in the technical literature. In this work we hope to fill what we view as a small open space in hydrologic literature: to provide a reference or guide for those interested in modem infiltration theory, to present the theoretical and mathematical basis of physically-based infiltration functions, and to indicate how to apply the theory to various hydrologic problems. It is assumed that the reader has an understanding of mathematics including appreciation of the basics of partial differential equations. However, mathematical complexities, especially lengthy derivations, will be avoided when not needed, especially where available in referenced material. The work outlined in Chapter 4 is important in support of the quality of the approximations used in Chapter 5, and for other reasons, but it is not necessary for the reader to understand all the mathematical complexities referred to there in order to understand the development of infiltration models in Chapters 5 and 6. Other scientists are more qualified to write on the mathematics of soil physics; it is important to note that the effort here is hydrologic: to present the theory supporting a scientifically valid approach to hydrologic problems which involve infiltration. The contributing authors support this work with several chapters reflecting significant expertise and experience in both mathematical theory and field applications. But as in most scientific efforts, the work is built on the contributions of many earlier investigators, some of whose names are referenced herein. John Philip and Yves Parlange deserve prominent mention. It is on their work that much of the theory presented here depends.
GRETA POINT: 631.432.3 SMI
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