Unsaturated-zone Modeling

Unsaturated-zone Modeling
Author: R.A. Feddes
Publisher: Springer
Total Pages: 0
Release: 2004-10-11
Genre: Science
ISBN: 9781402029172

Mankind has manipulated the quantity and quality of soil water for millennia. Food production was massively increased through fertilization, irrigation and drainage. But malpractice also caused degradation of immense areas of once fertile land, rendering it totally unproductive for many generations. In populated areas, the pollutant load ever more often exceeds the soil’s capacity for buffering and retention, and large volumes of potable groundwater have been polluted or are threatened to be polluted in the foreseeable future. In the past decades, the role of soil water in climate patterns has been recognized but not yet fully understood. The soil-science community responded to this diversity of issues by developing numerical models to simulate the behavior of water and solutes in soils. These models helped improve our understanding of unsaturated-zone processes and develop sustainable land-management practices. Aimed at professional soil scientists, soil-water modelers, irrigation engineers etc., this book discusses our progress in soil-water modeling. Top scientists present case studies, overviews and analyses of strengths, weaknesses, opportunities and threats related to soil-water modeling. The contributions cover a wide range of spatial scales, and discuss fundamental aspects of unsaturated-zone modeling as well as issues related to the application of models to real-world problems.

Soil Water Models

Soil Water Models
Author: R. DeJong
Publisher: Research Branch, Agriculture Canada
Total Pages: 46
Release: 1984
Genre: Agriculture
ISBN:

Numerical Simulation of Water Flow Through Unsaturated Soil in Vertical and Inclined Layered Systems

Numerical Simulation of Water Flow Through Unsaturated Soil in Vertical and Inclined Layered Systems
Author: Jorge L. Rodriguez
Publisher:
Total Pages: 249
Release: 2016
Genre: Computational fluid dynamics
ISBN:

In past decades, there were discussions explaining the mechanisms and factors that influence water flow through soil in unsaturated conditions. This phenomenon is of major importance to the mining industry as water is one of the trigger mechanisms for Acid Rock Generation (ARD) generation. In 1999, Newman evaluated water flow in unsaturated conditions for two column experiments using a vertical layer system of sandy materials and waste rock from the Golden Sunlight mine. Later in 2009, Andrina analyzed water flow using waste rock from the Grasberg Mine in three Meso-scale experiments to understand flow mechanisms for incline layers of waste rock. The current study focuses on modeling the two column experiments by Newman and the three Meso-scale panels by Andrina to analyze the mechanisms controlling water flow in unsaturated soils. Additionally, one of the models is evaluated under three additional materials to compare the effect of different hydraulic properties in an inclined layering system. With finite element methods, the experiments are modeled and calculated under equal boundary conditions. The use of climate boundaries recreates the precipitation flux and head pressure boundary to generate the suction from the discharge points. The models are run using SvFlux software, which runs an automatic mesh refinement algorithm and solves the Partial Differential Equations (PDEs) using FlexPDE. The models are validated based on the correlation of the discharge volume from each experiment. The results from the models describe the profile changes of head pressure (hp), flux, flow paths, and matric suction to describe the mechanism of flow in the unsaturated conditions. The validation of the models was achieved through back analyzing the different tests in the experiments, due to the low correlation of the model using the laboratory properties and the experimental results. The back analysis of the material is focused on the air entry value, and the saturated hydraulic conductivity as a means to change the unsaturated flow. The result from the research displays similarities and disagreements between the models and experiments. The models showed that the measured discharge from a particular material does not represent the preferential flow path of water, as a small gradient in the pressure distribution can generate breakthrough at the base of the system.

Functional Approach to Nonlinear Models of Water Flow in Soils

Functional Approach to Nonlinear Models of Water Flow in Soils
Author: G. Marinoschi
Publisher: Springer Science & Business Media
Total Pages: 325
Release: 2006-09-05
Genre: Mathematics
ISBN: 1402048807

This work of applied mathematics focuses on the functional study of the nonlinear boundary value problems relating to water flow in porous media, a topic which has not up to now been explored in book form. The author shows that abstract theory may be sometimes easier and richer in consequences for applications than standard classical approaches are. The volume deals with diffusion type models, emphasizing the mathematical treatment of their nonlinear aspects.