United States
Environmental Protection
AgencyOffice of Research andDevelopment
Washington DC 20460

EPA/600/R-96/095
August 1996

UNSODAThe UNSODA Unsaturated
Soil Hydraulic Database
User’s Manual
Version 1.0

EPA/600/R-96/095
August 1996

The UNSODA Unsaturated Soil Hydraulic Database
User’s Manual Version 1.0

byFeike J. Leij, William J. Alves, and Martinus Th. van Genuchten
U.S. Salinity Laboratory
U.S. Department of Agriculture, Agricultural Research Service
Riverside, California 92507
andJoseph R. Williams
Subsurface Protection and Remediation Division
National Risk Management Research Laboratory
Ada, Oklahoma 74820

IAG-DW12933934

Project Officer
Joseph R. Williams
Subsurface Protection and Remediation Division
National Risk Management Research Laboratory
Ada, Oklahoma 74820

NATIONAL RISK MANAGEMENT RESEARCH LABORATORYOFFICE OF RESEARCH AND DEVELOPMENT
U. S. ENVIRONMENTAL PROTECTION AGENCYCINCINNATI, OHIO 45268

DISCLAIMERS
The information in this document has been funded in part by the United States Environmental
Protection Agency under IAG-DW12933934 to the Agricultural Research Service, U.S. Departmentof Agriculture. Funding for this project by the Environmental Protection Agency pertained tosoftware development; the collection of soil hydraulic data and other information was outside thescope of this interagency agreement and was conducted independently by the U.S. Salinity
Laboratory. This document has not been subjected to the Agency's peer and administrative review
and therefore does not necessarily reflect the views of the Agency, and no official endorsement
should be inferred. Mention of trade names or commercial products does not constitute endorsement
or recommendation for use.
This report documents the UNSODA database management program for information on
unsaturated soil hydraulic properties and other soil information. UNSODA is a database for use in
the public domain and may be used and copied freely. The database program has been tested by anumber of individuals and was found to work correctly for most applications. No warranty can begiven, however, that the program is free of errors. The information contained in UNSODA has beenverified, as much as possible, by the contributors of the data. However, no guarantee can be givenby the authors of UNSODA regarding the validity and usefulness of the data; furthermore, no quality
assessment should be inferred from the inclusion or exclusion of data in UNSODA. If problems areencountered with the code, errors in the database information are found, or suggestions for
improvement of the database operation and its applications can be made, the authors listed below
or the Agency Project Officer can be contacted. Similarly, additional data sets for inclusion in the
UNSODA are welcome.

Bill Alves or Feike Leij
U. S. Salinity Laboratory
450 W. Big Springs Road
Riverside, CA 92507
Phone(909) 369-4846
FAX(909) 342-4964
e-mailfleij@ussl.ars.usda.gov

ii

ABSTRACTThis report contains general documentation and serves as a user manual of the UNSODA
program. UNSODA is a database of unsaturated soil hydraulic properties (water retention, hydraulicconductivity, and soil water diffusivity), basic soil properties (particle-size distribution, bulk density,organic matter content, etc.), and additional information regarding the soil and the experimental
procedures. The program can be used to (i) store and edit data, (ii) search for data sets based onuser-defined query specifications, (iii) write the contents of selected data sets to an output device,and (iv) describe the unsaturated hydraulic data with closed-form analytical expressions.
Mathematical models have become increasingly popular in the research and management offlow and transport processes in the subsurface environment. Because of improvements in computer
software and hardware, the usefulness of numerical models hinges more and more on the availabilityof accurate input parameters. The unsaturated hydraulic functions are key input data in numericalmodels of vadose zone processes. These functions may be either measured directly, estimatedindirectly through prediction from more easily measured data based upon quasi-empirical models,or approximated by using hydraulic data from similar soils. UNSODA serves as a repository of data
sets that can be used as a source of surrogate hydraulic data, or for the development and evaluationof indirect methods for estimating the unsaturated hydraulic properties.
UNSODA is written in C and operates in conjunction with the database program
KnowledgeMan® for storage of data in tables. This report gives a broad overview of major featuresand operations of UNSODA and documents the main tables. Furthermore, the data collection
process is outlined and each input variable is discussed. UNSODA allows the analytic descriptionof unsaturated hydraulic properties by means of parametric models; six default models are for thispurpose included in the program. The program module for optimization of hydraulic model
parameters is written in FORTRAN. Users can easily add additional hydraulic models. Three
examples are included to show the reader step-by-step how UNSODA can be used to (i) enter andedit data, (ii) search and report data, and (iii) model hydraulic data.

iii

ACKNOWLEDGMENTS
The authors wish to thank the many individuals who have contributed in small or large parts
with the development of UNSODA. Code development work by Shu-Min Chang, John Donahue,
Sustanie Harding, David Joyce, Boyle Mow, Ken Nguyen, Jasmina Shaw, and Renduo Zhang are
greatly appreciated, as well as the database design, data entry, and editing activities of Ulrike Bär,
Kim Holmes, Fereidoun Kaveh, Brad Nelson, and Walt Russell. Sincere appreciation is expressedto all individuals who contributed data to this project.

iv

FOREWORD
The U.S. Environmental Protection Agency is charged by Congress with protecting the Nation’sland, air, and water resources. Under a mandate of national environmental laws, the Agency strives
to formulate and implement actions leading to a compatible balance between human activities andthe ability of natural systems to support and nurture life. To meet these mandates, EPA’s research
program is providing data and technical support for solving environmental problems today andbuilding a science knowledge base necessary to manage our ecological resources wisely, understandhow pollutants affect our health, and prevent or reduce environmental risks in the future.
The National Risk Management Research Laboratory is the Agency’s center for investigationof technological and management approaches for reducing risks from threats to human health andthe environment. The focus of the Laboratory’s research program is on methods for the prevention
and control of pollution to air, land, water, and subsurface resources; protection of water quality inpublic water systems; remediation of contaminated sites and ground water; and prevention andcontrol of indoor air pollution. The goal of this research effort is to catalyze development andimplementation of innovative, cost-effective environmental technologies; develop scientific andengineering information needed by EPA to support regulatory and policy decisions; and provide
technical support and information transfer to ensure effective implementation of environmental
regulations and strategies.
The EPA uses numerous mathematical models to predict and analyze the movement of waterand dissolved contaminants in the saturated and unsaturated zones of the subsurface environment.
The usefulness of these models, and the accuracy with which model predictions can be made,depends greatly on the ability to reliably characterize the hydraulic properties of the unsaturated
zone. The accurate measurement of unsaturated hydraulic properties, i.e., water retention andhydraulic conductivity, is cumbersome and not feasible for many applications such as the assessmentof various strategies for dealing with soil contamination. Various indirect methods have beenutilized, and will likely be used in the future, for quantifying unsaturated hydraulic properties in analternative manner. This report documents the UNSODA database program for storing experimental
unsaturated soil hydraulic properties. UNSODA serves as a repository of measured unsaturated
hydraulic data, including the employed measurement methods, as well as other basic soil properties
and other general information. The database can be used to (i) store and edit data, (ii) search for data
sets based on user-defined query specifications, (iii) write the contents of selected data sets to an
output device, and (iv) describe the unsaturated hydraulic data with closed-form expressions.
UNSODA will be helpful for providing a wide variety of surrogate data that can be readily used incomputer models for (initial) estimates of flow and transport processes in the vadose zone, for thedevelopment and evaluation of indirect methods to generate soil hydraulic properties, and for
educational purposes. The information in this report provides a broad outline of UNSODA, andserves as a user's manual.
Clinton W. Hall, Director
Subsurface Protection and Remediation Division
National Risk Management Research Laboratoryv

vi

CONTENTS
Page
DISCLAIMERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
FOREWORD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1. Overview of Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2. Indirect Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3. Applications of UNSODA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4. Program Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.5. Screen and Program Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2. DATA COLLECTION AND GENERAL OUTLINE OF UNSODA . . . . . . . . . . . . . . 11
2.1. Data Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.2. Data Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.3. Main Modules of UNSODA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3. DATA ENTRY AND EDIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4. QUERY AND REPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5. PARAMETRIC MODELS FOR SOIL HYDRAULIC FUNCTIONS . . . . . . . . . . . . . . 30
6. DATABASE PROGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
6.1. Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
6.2. Description of Menu Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
6.3. Table Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
6.4. Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
7. EXAMPLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
7.1. Data Entry and Edit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
7.2. Query and Report Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
7.3. Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
APPENDICES
A. Questionnaire for Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
B.
Sample Form of Database Information for a Code . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
C.
Model Dependent Parts of RETC4.FOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
D. Menu Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
E.
List of Short Methodology Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
vii

FIGURES
NumberPage

1.

Example of UNSODA menu screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.

USDA-SCS soil textural triangle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.

Distribution of soil codes (data sets) across the USDA-SCS soil textural triangle . . 14

4.

Major soil textural groups in UNSODA and USDA-SCS Soil Survey Reports . . . . 14

viii

TABLES
NumberPage

1.

Distribution of Soil Codes over USDA-SCS Soil Textural Classes
in UNSODA and in Soil Survey Information Reports[after Table 1 of Carsel and Parrish, 1988] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122.

Standard Units, Format, Range, and Default Values of Numerical Fields . . . . . . . . . 19

3.

Type of Retention and Conductivity Functions in UNSODA . . . . . . . . . . . . . . . . . . 32

4.

Default Initial Estimates of Selected Parameters in Models for
Unsaturated Hydraulic Functions [after Carsel and Parrish, 1988] . . . . . . . . . . . . . 35

5.

Table Structure of UNSODA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

6.

Files for Data Tables in UNSODA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

7.

Illustration of Pointer Table for Laboratory D(2) Data . . . . . . . . . . . . . . . . . . . . . . . 52

8.

Pointer Tables for Tabular Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

9.

Outline of the Input File RETC.IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

10.

Miscellaneous Key Parameters in RETC4.FOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

ix

1. INTRODUCTION

1.1. Overview of Manual

The material in this report is intended to provide the rationale behind the database project
and to give a broad overview of the database program. The user is encouraged to peruse the manualto get a general impression of the type of data that can be stored in UNSODA (UNsaturated SOil
DAtabase), as well as the type of applications that are possible with UNSODA. However, one canonly become familiar with the program by using it; relevant instructions appear on the screen or canbe accessed through help menus. The reader should be able to use the program after consulting
section 1.4, which outlines the installation and execution procedure, and perhaps section 1.5, whichcontains information on screen formats and program structure.

Chapter 1 provides the rationale for the database project; it also discusses the utility of
indirect methods for estimating the unsaturated hydraulic properties (section 1.2) as well as otherpotential applications (section 1.3). The three major tasks for which UNSODA can be used are (i)the entry and editing of hydraulic and other soil data, (ii) retrieval of data from UNSODA, and (iii)
description of hydraulic data with parametric models. Chapter 2 discusses the data gathering
process, the distribution of the data sets over the soil textural groups. This chapter also lists the typesof data that can be included in UNSODA, and the main modules constituting UNSODA. These
modules are further reviewed in Chapters 3 through 5. The DATA ENTRY AND EDIT module is the
topic of Chapter 3, the type of information to be entered is discussed for each field. Standard units
for numerical fields are included as well as the averaging procedure for multi-valued tabular data.
Chapter 4 briefly reviews the QUERY AND REPORT module; a list of all query variables is includedin this chapter. The use of closed-form expressions for describing unsaturated hydraulic data, as
done with the module MODELS, is addressed in Chapter 5. This module is mostly based on the
RETC program [van Genuchten et al., 1991]. Expressions for the six default models of RETC to
describe hydraulic data are included. Chapter 5 also summarizes the optimization of hydraulicparameters. The database management program is briefly discussed in Chapter 6. In addition, a1

2

UNSODA 1.0

fairly lengthy description of all menu screens is furnished in section 6.2. This material parallels theinformation that can be obtained by running the database program. Information on all data tables
in UNSODA — the names of tables in which each field is stored, the data format, and the structureof tabular data tables — is contained in section 6.3. Section 6.4 outlines how the Fortran program
RETC4, which is used to optimize hydraulic data in UNSODA, can be modified to accommodateuser-defined parametric models. Several Appendices illustrate various aspects of how the data weregathered, the database structure, and the use of RETC4. Finally, Chapter 7 contains three examples
with screen output, to conveniently let the reader of this manual become a user of the program.

In summary, the reader is encouraged to start using the software, to consult this manual forassistance if necessary, and to become familiar with the capabilities of UNSODA. Chapter 1
explains how to get started, Chapter 2 lists what the program can do, Chapters 3 through 5 discuss
how this can be done, Chapter 6 documents the menu and table structure, and Chapter 7 gives a stepby-step illustration of using UNSODA for three different purposes.

1.2. Indirect Methods

Knowledge of the unsaturated hydraulic properties is indispensable to better understand andmanage the transport of chemicals and the flow of water in the vadose zone of soils. Such processes
have long been important for agriculture since they govern the movement of water and nutrients
toward root systems of crops. More recently, this direct interest in flow and transport processes
aimed at creating an optimal habitat for crop growth, has been overshadowed by a general concernthat the quality of the subsurface environment is being adversely affected by the presence ofchemical substances as a result of industrial, agricultural, and other activities.

The movement of chemicals in the subsurface is largely determined by the rate and directionof water flow. Unfortunately, the measurement and description of water flow in unsaturated soils
is difficult because of the nonlinearity of the unsaturated soil hydraulic properties. For example, theChpt. 1. INTRODUCTION

3value of the unsaturated hydraulic conductivity typically varies several orders of magnitude over thecomplete range of saturation. Many numerical models have been developed and are now routinely
used to investigate and manage the movement of water dissolved substances into and through theunsaturated zone of soils. Methods for the direct measurement of soil water retention and,especially, the unsaturated hydraulic conductivity have not kept pace with advances in numericalmodeling. The success of numerical models greatly depends on the availability of reliable input data.
Particularly the relationships between water content (2), pressure head (h), and hydraulicconductivity (K) or soil-water diffusivity (D), are important since they quantify the rate at whichwater and chemicals move through the vadose zone. Many laboratory and field methods have beendeveloped for measuring these relationships on disturbed or undisturbed porous media [Klute, 1986].
Unfortunately, such methods remain cumbersome and time-consuming despite decades of work bysoil physicists and others representing different disciplines. It is not likely that breakthroughs inexperimental technology will remedy this situation in the near future, particularly in view of theextensive data requirements for deterministic and stochastic field studies of flow and transport in thevadose zone. Furthermore, experimental results are often subject to considerable uncertainty(especially for K and D), whereas spatial variability in the field may limit their usefulness formodeling purposes. Hence, rather than through direct measurement, a case can be made for the useof alternative methods to quantify the unsaturated hydraulic properties.

An alternative to direct measurement of the unsaturated hydraulic properties is the use,analysis, and/or generalization of experimental data that are already available. The appropriatenessof this approach depends on the type of application for which such surrogate hydraulic data are to
be used, and the similarity in soil textural and structural properties between soils for which data isavailable and those for which hydraulic data is lacking. Practitioners can benefit from this approachby having quick estimates of the hydraulic properties of soils for which only limited data are
available.

4

UNSODA 1.0
A second alternative is to deduce hydraulic properties from more easily measured soil

properties by using physico-empirical models based on a simplified flow process through the porous
medium. Since the hydraulic conductivity is the most difficult to measure, many research efforts
have been devoted to the prediction of the conductivity from measured soil water retention data. The
hydraulic conductivity may be predicted theoretically using statistical pore-size distribution models,
which assume water flow through "idealized" cylindrical pores. Water flow is described with theequations of Darcy and Poiseuille [cf. Mualem, 1986], while Laplace's law is used to express thepore system in terms of pressure heads instead of pore radii. This approach assumes that estimatesof the soil water retention curve are available. Measured input retention data are generally fitted byanalytical expressions that are more convenient for calculating of the hydraulic conductivity. Even
if no measured retention data are available, they can still be generated from physico-empirical andempirical models using particle-size distribution data and other basic soil properties. The particlesize distribution is then used to estimate the pore-size distribution from which subsequently thepressure head is obtained using Laplace's law. Predictive conductivity equations that fit this moldhence are actually particle-size distribution models.

As a third alternative, purely empirical models can be used to estimate the hydraulicproperties. Such approaches predict soil-water retention from a variety of soil information, including
data on the particle-size distribution, bulk density, and organic matter content. Lately the term pedotransfer functions (PTF) has been used to characterize models that translate soil texture and otherbasic soil properties into soil hydraulic curves [Wösten and Bouma, 1992]. Functions for the soil
water retention and hydraulic conductivity curves can be obtained through regression analysis [cf.
Vereecken et al., 1989; Vereecken et al., 1990] using data sets for which both hydraulic data andother, more easily measured soil properties, are available. This approach has been especially popular
for the water retention curve, one of the reasons being the interest of agronomists in the amount ofavailable water in a soil profile. Correlation techniques have not been used as widely for describing
the hydraulic conductivity curve. Likely reasons are that relatively few complete conductivity data

Chpt. 1. INTRODUCTION

5

sets are available, while the conductivity itself is influenced by many textural and structural soil
properties which may be difficult to quantify.

The development or validation of (physico)-empirical models requires the availability ofmeasured 2(h) and K/D data, as well as basic soil properties that may influence the hydraulicbehavior of soils. The hydraulic data should be for a wide variety of soils and experimental
procedures. Pertinent information should include data on the hydraulic functions and other soil
properties, soil classification, and a description of measurement procedures.

Additionally,parametric models are needed to describe the hydraulic data. The objective of the project leading
to this manual was to develop an international database containing such information. Data in theUNsaturated SOil DAtabase (UNSODA) were gathered from the literature or were obtained throughpersonal requests to scientists and engineers. UNSODA is intended to facilitate the research andmanagement of flow and transport processes in the vadose zone. A successful database of this typeshould incorporate different data types with a wide range in quality. Also, an effort was made toalways document experimental methods and, whenever possible, to approach a contact person forverification and rating of the data. Still, the approach retains an element of subjectivity. Hence,
database users must make a final decision about the appropriateness of the data for their application.

UNSODA does not represent the first effort to combine unsaturated soil hydraulic data. Soilscientists and hydrologists in several countries have established data collections. Mualem [1976a]
previously established a widely used data catalogue to investigate predictive methods for theunsaturated hydraulic conductivity. Wösten et al. [1987] published tabulated functions of averaged
hydraulic properties for some 20 different soil groups. These were based on 197 individual curves.
Other databases have been established for Australia, Belgium, Hungary, and the United States.
However, UNSODA does represent, to the best of the authors’ knowledge, the first truly
international set of retention and conductivity data compiled in a relational database program
published for use in the public domain. The purpose of this manual is to acquaint the reader withthe database and to document the data collection and software development.

6

UNSODA 1.0

1.3. Applications of UNSODAIn Chapter 7 the use of UNSODA for several specific purposes will be demonstrated. Someof the general applications of UNSODA are listed below:
1. Research and evaluation of parametric and physico-empirical models to describe 2(h) and/or
K/D by fitting such models to hydraulic data. UNSODA provides a valuable source of
hydraulic properties for soils with different textural and structural properties, which are obtainedin the field or laboratory on disturbed or undisturbed samples using a variety of methods.

2. Development of empirical equations (pedo-transfer functions) to predict hydraulic properties
from such data as particle-size distribution, mineralogy, cation exchange capacity, bulk density,and mineralogy.

3. Determination of parameters in hydraulic models so as to more efficiently represent hydraulicdata of different soils and soil horizons. Parametric models can be used for comparative
purposes, or for scaling to characterize the spatial variability of soil hydraulic properties.

4. Use hydraulic properties of soils in UNSODA as a surrogate for cases where insufficient data
are available. Because hydraulic properties greatly depend on soil texture and soil structure, one
may infer the hydraulic properties of a particular soil — for which no hydraulic properties areavailable — from other soils with a similar texture and structure.

5. Making comparisons of different experimental methods for determining soil hydraulicproperties, or for comparing results for disturbed and undisturbed samples.

6. Use as a repository of hydraulic and other soil information to meet general research andeducational needs.

Chpt. 1. INTRODUCTION

7

1.4. Program Installation

UNSODA was developed with an IBM-PC, DOS compatible computer as the targeted
environment. The code is written as a stand-alone program such that no supporting databasemanagement system is necessary. The database management program was written in Microsoft®
C (version 7.0) using the KnowledgeMan® (version 2.5) KC library from Micro Data Base Systems.
The PC on which UNSODA is used must have a base memory of 512 KByte or better, with at least
5 MByte of free disk space on the selected drive. The program can run on machines with INTEL;a math coprocessor is recommended. Output can be written to the screen, disk, or printer. The
printer must be connected to the LPT1 port. In most cases, the CONFIG.SYS file should include:
files=55
buffers=20
device=c:\dos\ansi.sys

Instructions regarding the installation procedure can also be found in the READ.ME file,whose information may be more recent than given in this section. It is recommended that users firstmake a backup of the original disk and save the latter. For the following instructions, it will beassumed that the installation disk containing the (compressed) database program is in drive A. For
the program to work from a default directory on the C-drive type "A: " and press <Enter> or 5 andsubsequently type "install C:", i.e.,
C>a: 5
A>install c:5
The subdirectory UNSODA will be created off the root on the C-drive. All UNSODA files,
data as well as executable files, will be copied from the A-drive to this subdirectory UNSODA on
the C-drive and automatically decompressed. To run UNSODA, type "start" (execute START.EXE):
C:\UNSODA\start 5Users can go from the introductory screen to the main menu by hitting any key. After the data tables
have been copied to the default directory, the first operation required as part of the installation

8

UNSODA 1.0

procedure is to reindex all the data tables. To perform this operation select the UTILITIES menu from
the Main menu, then select Reindex Data Tables. Reindexing should also be done when data arechanged. For subsequent use of UNSODA — after the installation procedure — the user needs to
go directly to the subdirectory C:\UNSODA and type "START."The executable version of the program can be distributed freely. A disk with the source code
files of UNSODA and/or data tables are available upon request from the authors. Updates of
UNSODA are anticipated to become available in the future.

1.5. Screen and Program Format

Figure 1 outlines a typical screen. The center (box) of the screen shows selections for the
next menu or contents of the database, the bottom box contains keystroke options (keys are denotedby pointed brackets, < >), while the box at the top of the screen typically displays the title of thecurrent menu (--- ---). The right-hand part of the upper box usually contains the sequence of pastmenus and the name of the soil for which data are being shown. Each data set is denoted with a code
shown on the left in the top box. In common database terminology the soil code may be viewed as
the record number, with each record (soil) having several data types or fields. The fields (data) canbe numerical (bulk density), tabular (water retention), or alphabetical (keyword). A list of soil codes
Figure 1. Example of UNSODA menu screen.

Chpt. 1. INTRODUCTION

9can be accessed in several modules of UNSODA, for example by selecting UTILITIES from the Mainmenu. Typically, selections for a subsequent screen can be made by typing a number or letter(1, .., 9, a, b), or by moving the cursor with the arrow key (<89>) to the desired selection andpressing <Enter>. Pressing the <Esc> key usually means a return to a previous menu whileabandoning the current task, i.e., nothing is being saved. The Help screen is accessed by hitting thefunction key <F1>. Other keys that may be used, such as <PgUp>, <PgDn>, <Home>, <End>,<F2>, <F10>, are shown in the bottom box. The Help screen further explains key functions.

Users are encouraged to peruse this manual before and while running UNSODA. Not allparts of the manual or program may be of interest. One could focus first on the material pertaining
to the four main modules of UNSODA as further discussed in section 2.3. These modules are: (1)DATA ENTRY AND EDIT, (2) QUERY AND REPORT, (3) MODELS, and (4)UTILITIES. The first module
should be of particular interest to users who have hydraulic data and want to enter them into
UNSODA. The second option, QUERY AND REPORT, lets the user search for some or all of the data,
and write data to an output device. Thirdly, the user can fit parametric models to hydraulic data withthe routine MODELS. Finally, the UTILITIES module may be used to delete, change, or list codes; toreindex, sort, or evaluate tabular data; and to view files in the UTILITIES module. Most screens offer

10

UNSODA 1.0

access to a Help screen, which gives more information on the item to be selected or for which avalue needs to be specified. This manual provides a broad overview of UNSODA.

2. DATA COLLECTION AND GENERAL OUTLINE OF UNSODA

2.1. Data Collection

The data in UNSODA are primarily from contributions by individual scientists, while somedata sets were extracted from the literature. A questionnaire1 was prepared to request information
for UNSODA. The questionnaire was partly based on suggestions from participants at aninternational workshop on soil-hydraulic properties held in Riverside in 1989 [van Genuchten et al.,1992]. The aim was to obtain a fairly wide range of information, including experimental procedures
and information on soil classification.

This broad information may, among other things,

accommodate future users whose needs are presently still unknown. There appeared to be a wide
range in quality and quantity in data that were supplied. Hence some subjective judgments weremade as to which data were to be included in the database, and to avoid excessive amounts ofsometimes esoteric data that could have reduced the efficiency and utility of the database.

Efforts by both data providers and the authors were hopefully minimized through a judicious
choice of the format of the questionnaire. The questionnaire, as shown in Appendix A, is tailoredto the database format in UNSODA. The questionnaire contains sections for: (1) Descriptor Data,(2) Methodology, (3) Soil Properties, and (4) Unsaturated Hydraulic Properties. Approximately 240
questionnaires were sent to scientists and engineers in many countries to solicit input for UNSODA.
There were more than 100 responses varying from simple acknowledgments to forms filled out indetail, and with data provided on floppy disks. Frequently, data sets could not be considered becauseof a lack of K/D data — the unsaturated hydraulic conductivity, K(h) or K(2), and the soil water
diffusivity, D(2). Almost all remaining data sets required a substantial amount of preparation(reading literature, editing, and digitizing) before entry into UNSODA. After entry of suitable data
in UNSODA, the information was sent back to the contributors for review. A preliminary survey

1

The data gathering process for UNSODA was an activity outside the scope of the interagency
agreement between USDA and EPA

11

12

UNSODA 1.0

of the literature for hydraulic data was also conducted; data sets were also extracted from theliterature.
Figure 2 shows a textural triangle with percentages clay (<2µm), silt (2-50 µm), and sand(>50µm) according to the USDA-SCS classification scheme. Figure 3 exhibits the distribution ofdata sets in UNSODA according to this triangle. As is apparent from Figure 3, a large portion of thesoils in UNSODA are sands and loamy sands. Table 1 and Figure 4 illustrate that the coarse-textured
soils are somewhat over-represented in UNSODA — the relative number of sands is more than fourtimes higher in UNSODA as compared to the much larger database used for soil classification. On
the other hand, fine-textured soils (cf. clay loam, silty clay loam, silty clay) are included less in
UNSODA. This may reflect a bias of experimentalists towards using soils for which the hydraulicproperties are more conveniently determined.

TABLE 1. Distribution of Soil Codes across USDA-SCS Soil Textural
Classes in UNSODA and in Soil Survey Information Reports[after Table 1 of Carsel and Parrish, 1988]
Textureclassn

UNSODA%n

Soil Survey
%

Sand

184

23.59

803

5.10

Loamy sand

64

8.21

881

5.60

Sandy loam
Sandy clay loam

133
52

17.05
6.67

2835
610

18.01
3.88

Silt
Silt loam

3
142

0.38
18.21

115
3050

0.73
19.38

Clay loam
Loam
Silty clay loam

36
70
33

4.62
8.97
4.23

1317
1991
1882

8.37
12.65
11.96

Sandy clay
Silty clay
Clay

3
21
39

0.38
2.69
5.00

74
1002
1177

0.47
6.37
7.48

Total

780

100.0015737

100.00Chpt. 2. DATA COLLECTION AND GENERAL OUTLINE

0

13

100
90

10
20

80

30

70

% sand% clay40( > 50

60

C

50

m)

50

60

siC

sC

70
80

cL

S lS
0

sicL

10

20

m)

30

scL

20

90

100

(<2
40

sL
30

10

L
siL
40

50

60

70

Si
80

90

100

% silt( 2 - 50

S
lS
sL
scL
Si
SiL

Sand
loamy Sand
sandy Loamsandy clay LoamSilt
silt Loam

m)

cL
cL
L
sicL
sC
siC
C

clay Loamclay Loam
Loamsilty clay Loamsandy Clay
silty Clay
Clay

Figure 2. USDA-SCS soil textural triangle.

14

UNSODA 1.0

100

0

90

10
20

80

30

% sand( > 5070

50m)% clay

60

40

50

60

(<2

m)

40
30

70
80

20
10

90

100

0
0

10

20

30

40

50

60

70

80

90

100

% silt( 2 - 50m)

Figure 3. Distribution of soil codes (data sets) across the USDA-SCS soil textural triangle.

UNSODA

Soil Survey
sandy loams

sands
silt (loam)

sandy loams
clays
silt (loam)(clay) loams

sands
clays

(clay) loams

Figure 4. Major soil textural groups in UNSODA and USDA-SCS Soil Survey Reports.

Chpt. 2. DATA COLLECTION AND GENERAL OUTLINE

15

2.2. Data Types

A different code number was used for each individual soil sample or horizon for which acomplete set of hydraulic data (soil texture, water retention, and hydraulic conductivity or diffusivity)
was available. Because some experiments generate large amounts of similar data, the number of data
sets/codes for a particular soil or experiment was limited arbitrarily to avoid repetition and to keep
the size of the database manageable. The following data groups were used for each soil code:

Descriptor Data. Family, Series, Texture, Structure, Position and Name of Horizon, Depth
to Ground water, Location and Site, Climatic Data, Date, Publication, Contact Address, Ratingof Data Quality, Name of Rater, Comment, and Keyword.
Soil Properties. Bulk and Particle Density, Porosity, Organic Matter Content, Saturated
Conductivity (Ks), Saturated Water Content, Cation Exchange Capacity (CEC), pH, Electrolyte
Level, Sodium Adsorption Ratio (SAR), Exchangeable Sodium Percentage (ESP), Electrical
Conductivity (EC), Fe and Al Oxides, Comment.
Methodology. Key Words for Measurement of Field and Laboratory 2(h), K/D, and Ks, anda Description of Field and Laboratory Procedures.
Tabular Data. Data with an independent and a dependent variable: Particle Size
Distribution, Dry Aggregate Size Distribution, Mineralogy, Field and Laboratory2(h), K(2), K(h),and D(2).
Appendix B contains a soil code with actual data from Dane et al. [1983]. This appendix,
along with the questionnaire, serves as an example of data preparation for potential contributors.
The input for UNSODA is discussed in more detail in Chapter 3.

16

UNSODA 1.0

2.3. Main Modules of UNSODA

The following overview of the main modules in UNSODA should give readers an impressionof the potential applications of UNSODA. The first three modules are discussed in more detail in
Chapters 3, 4, and 5.

DATA ENTRY AND EDIT
1. Create a New Soil Code and Enter Data
2. Append Tabular Data for an Existing Code. Enter tabular data (distribution of particle oraggregate size and mineralogy, hydraulic data). Specify wetting and drying curves forhydraulic data.
3. Delete Tabular Data for an Existing Code.
4. Edit Any Data for an Existing Code. Modify any data for an existing code.
5. Conversion Factors for Dimensions. Specify dimension factors to convert units of "raw" data
to standard units for UNSODA.
6. List Codes and Series Names. Write contents of UNSODA (code number, series name, andtexture) to screen.

QUERY AND REPORT
1. Specific Codes. Report the contents of codes meeting query specifications.
2. All Codes. Report the contents of the entire database.
3. Specific Tabular Data. Write selected tabular of codes meeting query specifications to disk,
screen, or printer.
4. List Codes. Write contents of UNSODA (code number, series name, and texture) to thescreen.

Chpt. 2. DATA COLLECTION AND GENERAL OUTLINE

17

MODELS
1. Add/Delete Model Name. Enter or delete names of analytical models for hydraulic functions.
2. Execute RETC Optimization. Provide initial estimates for model parameters and conduct
parameter optimization with program RETC [van Genuchten et al., 1991]; default initialvalues are based on soil texture.
3. View RETC Results or any other File. View results of the parameter estimations, write
results to disk, or store parameters in UNSODA.

UTILITIES
1. Delete Code. Delete codes (erase record from UNSODA).
2. Change Code. Renumber codes (change number of record).
3. List Codes. Write contents of UNSODA (code number, series name, and texture) to thescreen.
4. Reindex Data Tables. Reindex tabular data tables.
5. Sort Tabular Data. Sort tabular data in ascending order and take geometric average.
6. Check Pointer Tables. Inspect pointers of tabular data for discrepancies.
7. View Text or Data Tables. Display files from specified directories on the screen.

3. DATA ENTRY AND EDIT

This part of the manual describes the "protocol" for data preparation and entry. Because of
the wide range in quality and quantity of data as a result of differences in experimental conditions
and objectives during data gathering, it is impossible to always adhere to a consistent data format
for entry in UNSODA. The description and quantification of information is greatly subjective. It
has been the authors’ impression that few publications are primarily dedicated to obtain high quality
data. In many instances the major objective of a publication was to study various soil physicalconcepts at the laboratory or field scale, or to report on new or improved methodology. Because ofthis lack of scientific interest and the scarcity of funding for data collection, there are few soil
physical studies whose major thrust is to obtain high-quality hydraulic data. This is in contrast withother soil science disciplines where data collection itself is often the primary concern (e.g., soil
survey, soil testing). As a result, no statistical information on hydraulic data is generally provided.

The (input) fields for UNSODA will first be reviewed. This information may be useful when
preparing data for input or when using the DATA ENTRY AND EDIT module. The numerical data in
UNSODA can be made dimensionally consistent by adhering to the standard units listed in Table
2. Table 2 provides a listing of all input fields. If for some reason the original (unedited) data havedifferent units, UNSODA can automatically change their values to express the same data in standard
units. This is done by first specifying appropriate conversion factors (through the main module
UTILITIES) before the original values are entered (through the main module DATA ENTRY AND EDIT).
Table 2 also states the variable type — character string, integer, or real — for reading data and forinternal use, in some cases with a type conversion. The length of the field that can be entered isspecified, as well as the minimum and maximum of acceptable values. If no data is entered, theprogram assigns a default value to the field to identify that no data exist for the field; the last column
in Table 2 shows these default values.

Ordinarily the user need not be concerned with theinformation provided in Table 2.

18

Chpt. 3. DATA ENTRY AND EDIT

19

Table 2. Standard Units, Format, Range, and Default Values of Numerical Fields

Field

Unit

Read asUsed asLengthMinimum

Maximum

Default

Family-stringstring

50

-

-

""

Series Name-stringstring

30

-

-

""

Texture-stringstring

25

-

-

""

Structure-stringstring

35

-

-

""

Upper Depthcm

stringinteger80.000199999999

0

Lower Depthcm

stringinteger80.000199999999

0

Horizon-stringstring

7

-

-

""

Ground watercm

stringreal

100.00019999999999

0.0

Location-stringstring

60

-

-

""

Site

-

stringstring

25

-

-

""

Annual Rainfallcm

stringreal

100.00019999999999

0.0001

o

C

real

real

10

-999999999

9999999999-999.0

o

C

real

real

10

-999999999

9999999999-999.0Date-stringstring

8

-

-

""

Publication Info.

-stringstring

240

-

-

""

Contact-stringstring

240

-

-

""

Rating (0-10)-integer

integer

2

0

10

0

Rated by-stringstring

40

-

-

""

Comment-

stringstring

480

-

-

""

Keyword-stringstring

111

-

-

""

Descriptor Data 1

Depth toAvg. Temperature
January (C)Avg. Temperature
July (C)

Descriptor Data 2

20

UNSODA 1.0

Table 2. Continued

Field

Unit

Read asUsed asLengthMinimum

Maximum

Default

Bulk Density

g/cm3

real

real

10

-999999999

9999999999

0.0

Particle Density

g/cm3

Soil Properties

real

real

10

-999999999

9999999999

0.0

Porosity3

cm /cm

real

real

10

-999999999

9999999999

0.0

Org. Mattermass %

real

real

10

-999999999

9999999999

0.0

Sat. Conduct.

cm/d

real

real

10

-999999999

9999999999

0.0

Sat. Water Cont.

cm3 /cm3

real

real

10

-999999999

9999999999

0.0

CEC

cmol/kg

real

real

10

-999999999

9999999999

0.0

pH

-

real

real

10

-999999999

9999999999

0.0

meq/l

real

real

10

-999999999

9999999999

0.0

SAR

mmol1/2/l1/2

real

real

10

-999999999

9999999999

0.0

ESP

%

real

real

10

-999999999

9999999999

0.0

EC

dS/m

real

real

10

-999999999

9999999999

0.0

Fe and Al Oxide

mass %

real

real

10

-999999999

9999999999

0.0-

stringstring

240

-

-

""

Particle Size

µm

real

real

8

-9999999

99999999-

Fraction

g/g

real

real

8

0

1.1

-

Mineralogy-

stringstring

30

-

-

""

Aggregate Size

mm

real

real

8

-9999999

99999999-

Pressure Head

cm-H2 O

real

real

8

-9999999

99999999-

Water Content

cm3/cm3

real

real

8

0

1

-

Conductivity

cm/d

real

real

8

-9999999

99999999-

Diffusivity

cm2 /d

real

real

8

-9999999

99999999-

Electrolyte Level

Comment

3

Tabular Data

Chpt. 3. DATA ENTRY AND EDIT

21

When creating a database record, a new code number has to be specified. The numberingsystem is based on increments of 10 for records unrelated to other codes, while an increment of 1
is used for related records (i.e., the same experiment or location but for a different soil horizon ortreatment). This numbering system should become clear when using the List option. Default code
numbers can be selected from the screen when selecting Create in the DATA ENTRY AND EDIT
module; the fields for this module are listed below as they appear on the screen.

Descriptor Data 1
Family. Enter the soil family name, if available, or a similar identifier, and specify to whichclassification system the terminology applies (this can also be done as a comment on the nextscreen). For further information see the publication by the Soil Survey Staff [1990].
Series Name. For each code a series name or another distinct name, based on the soil
location, should be entered. Identical series names may be numbered.
Texture. For each code the textural classification must be entered based upon the USDASCS triangle using the mass fraction corresponding to the equivalent particle diameters between
0-2 µm (clay), 2-50 µm (silt), and >50 µm (sand). Note that in UNSODA only the USDA-SCS
classification can be used since queries depend on an exact match while the USDA-ARS
classification is also needed to obtain default estimates in the RETC optimization. If the massfraction is not known for one or more of these equivalent diameters, interpolate or extrapolate
from the available particle-size data assuming a lognormal distribution. For Code 2550, forexample, the cumulative fractions <2µm, <20µm, and <2000µm are 0.112, 0.259, and 1.000.
First, the slope of the log-transformed curve in the silt range is estimated; after which the
cumulative fraction, x, for <50µm can be obtained:
slope '

log20 & log2
' 6.8030.259 & 0.112

Y

x 'log50 & log20% 0.259 ' 0.317
6.803

The sample contains 11.2% clay, 20.5% silt, and 68.3% sand and should therefore be classified
as a sandy loam according to the textural triangle in Figure 2.

22

UNSODA 1.0
Structure. Describe the soil structure, particularly as it relates to aggregate stability.
Upper Depth. Distance between the soil surface and the top of the sample, core, or profile
for which measurements are reported. The preferred unit is cm.
Lower Depth. Give the distance between the soil surface and the bottom of the sample, core,or profile for which measurements are reported. Note that this lower depth is normally greaterthan the upper depth in the previous field. The preferred unit is cm.
Horizon. Provide the soil horizon according to conventional soil taxonomy.
Depth to Ground Water. Give the distance between the soil surface and a typical positionof the ground-water table. The preferred unit is cm.
Location. Provide the approximate location of the in situ measurement or sampling site incommon geographical terms readily identified on a map (city, state or province, and country).
Site. Provide the site of the in situ measurement or sampling site in more detail than isentered under Location.
Annual Rainfall. Give the average annual precipitation (rainfall) in the proximity of the site.
The preferred unit is cm.
Avg. Temperature January (C). Specify the average temperature in January at or close to
the site. The preferred unit is degrees Celsius.
Avg. Temperature July (C). Specify the average temperature in July near the site. The
preferred unit is degrees Celsius.

Chpt. 3. DATA ENTRY AND EDIT

23

Descriptor Data 2 (at least one field must be entered)Date. Give the date of the measurements as month/day/year, e.g., 06/18/92. Approximate
if the measurements are taken over a period of time, e.g., 03-07/92 for experiments from March
to July 1992.
Publication Info. Provide one or more references which contain data for the soil code oroutline experimental procedures. Provide only essential information, i.e., abbreviated journal
name, page numbers, and number and year of issue. Sources that are relatively accessible are
preferred.
Contact. Give the name, address, and phone and fax numbers of the individual to becontacted for further information regarding the data or methodology for the soil code.
Rating (0-10). Rate the quality of the data on a scale of 1 through 10, where 10 denotes thebest possible way to quantify the soil hydraulic properties with current methodology and 0
implies that no rating is available.
Rated by. Enter name of the individual who provided the rating.
Comment. Enter short comment regarding the above general information, e.g., agriculturaluse of soil, geological or topographical information.
Keyword. Enter keywords describing the type of data or study for possible use queries. A
distinction is often made between disturbed and undisturbed samples. Other keywords could
characterize the objectives of the study. Typical entries are: Disturbed, Horizontal, Hysteresis,
Multiphase, Overburden, Salinity, Soltrol, Tillage, Undisturbed, and Vertical.

24

UNSODA 1.0
Soil Properties
Bulk Density. Provide dry bulk density as mass of solids per bulk volume.
Particle Density. Provide particle density as mass of solids per volume of solids.
Porosity. Provide measured porosity of soil as volume of voids per bulk volume. Do not
specify a value calculated from the bulk and particle densities.
Organic Matter Content. Enter the mass of organic matter content as a percentage of thetotal solid mass. If necessary estimate organic matter content based on carbon content andexplain in the comment field.
Saturated Conductivity. Enter the measured saturated hydraulic conductivity. If necessary
state as a comment if the value is obtained in the field or the lab, and on a vertical or a horizontal
sample.
Saturated Water Content. Enter the experimental water content of a water-saturated
sample. Explain in a comment how the measurement was made (e.g., capillary rise).
Cation Exchange Capacity. Enter the value for the CEC in cmol of charge per kg of dry soil
(i.e., meq/100 g soil).
pH. Enter the value of the measured soil pH. Describe the type of suspension as a comment.
Electrolyte Level. Enter the approximate total solute concentration of the soil solution
during the experiments.
SAR. Enter the Sodium Adsorption Ratio.
ESP. Enter the Exchangeable Sodium Percentage.
EC. Enter the electrical conductivity of the saturation extract.
Free Fe and Al Oxide. Enter the mass fraction of these oxides as a percentage of the total
solid phase.
Comment. Describe with some keywords the experimental procedures used to obtain thebasic soil properties listed in this table. Adhere to terminology as used in Klute [1986] and Pageet al. [1982].

Chpt. 3. DATA ENTRY AND EDIT

25

Methodology
The methodology section consists of a maximum of six short characteristic comments regarding
the measurement of hydraulic properties and two longer comments regarding laboratory and fieldprocedures. A list with short characteristic comments is included in Appendix C. The list isadmittedly somewhat subjective; it reflects a lack of standard procedures for determining soil
hydraulic properties.
Field 2(h). Describe the field measurement of the water retention curve, 2(h), with a few
keywords for the equipment used. Specify how the water content (e.g., neutron scattering) andthe pressure head (suction) were determined (e.g., tensiometry).
Lab 2(h). Describe the laboratory measurement of 2(h); specify how water content andpressure head (suction) were determined using a few keywords to describe equipment.
Field K/D. Describe the field measurement of the hydraulic conductivity, K(2) or K(h), or
soil water diffusivity, D(2), with a few keywords to outline the concept of the measurement.
Specify the methodology (e.g., instantaneous profile) and, if applicable, whether diffusivity wasmeasured instead of conductivity.
Lab K/D. Describe the laboratory measurement of the hydraulic conductivity, K(2) or K(h),or soil water diffusivity, D(2), with a few keywords to outline the concept of the measurement.
Specify the methodology (e.g., double plate) and, if applicable, whether diffusivity was measured
instead of conductivity.
Field Ksat. Describe the field measurement of the saturated hydraulic conductivity, Ks, witha few keywords (e.g., double ring infiltrometer).
Lab Ksat. Describe the laboratory measurement of Ks using a few keywords to outline theconcept of the measurement (e.g., constant head).
Field Comment. Describe the experimental procedures in the field, e.g., sampling technique,installation of equipment, sample and plot sizes, frequency of measurements, data analysis.
Lab Comment. Describe the experimental procedures in the laboratory, e.g., installation andtype of equipment, sample sizes, frequency of measurements, ambient temperature, data analysis.

26

UNSODA 1.0
Tabular Data Type
Tabular data consist of pairs of independent and dependent variables. By specifying theappropriate conversion factors, one can enter values in the original units which are subsequently
converted automatically to the standard units of UNSODA. Upon completion of data entry, thedata can be sorted and averaged in the UTILITIES module by selecting the Sort Tabular Data
Option. Sorting occurs in ascending order for the independent variable. Averaging is done to
avoid multi-valued functions. If there are n values of the dependent variable, yi, for the samevalue of the independent variable, the program will take the geometric mean according to:n

1ȳ ' expln (yi )n i'1
Particle Size Distribution. Cumulative fraction of soil mass as a function of the equivalent
particle size or diameter (the preferred unit is µm).
Dry Aggregate Size Distribution. Cumulative fraction of soil mass as a function of theequivalent dry aggregate size or diameter (the preferred unit is mm).
Mineralogy. Mass fraction (g/g) of individual soil or clay minerals.
Field 2(h). Volumetric water content, 2 (cm3/cm3), as a function of soil pressure head, h(cm), for observations in the field.
Field K(2). Hydraulic conductivity, K (cm/d), as a function of volumetric water content, 2(cm3/cm3), for observations in the field.
Field D(2). Soil water diffusivity, D (cm2/d), as a function of volumetric water content, 2(cm3/cm3, for observations in the field.
Field K(h). Hydraulic conductivity, K (cm/d), as a function of soil matric head, h (cm), forobservations in the field.
Lab 2(h). Volumetric water content, 2 (cm3/cm3), as a function of soil matric head, h (cm),for observations in the laboratory.
Lab K(2). Hydraulic conductivity, K (cm/d), as a function of volumetric water content, 2(cm3/cm3), for observations in the laboratory.

Chpt. 3. DATA ENTRY AND EDIT

27

Lab D(2). Soil water diffusivity, D (cm2/d), as a function of volumetric water content, 2(cm3/cm3), for observations in the laboratory.
Lab K(h). Hydraulic conductivity, K (cm/d), as a function of soil matric head, h (cm), forobservations in the laboratory.

4. QUERY AND REPORTUNSODA facilitates queries for parameters characterizing the soil, the invoked experimental
procedures, or the location. Data for codes that match the query profile can be written in ASCII form
to the screen, printer, or disk. The data can be made up of the entire contents of a record (code) or
pre-defined tabular data. This latter option is attractive when hydraulic data are needed for otherapplications.

A list of query variables is given below. It may be advisable to browse through the database
contents (query All Codes and write contents to screen) before starting a search. Note that thismodule does not distinguish between upper and lower case spelling.

Code. Enter a code number. A search can be conducted for code numbers less, less or equal,
equal, greater or equal, or greater than the specified value.
Rating. A search can also be conducted based on a (subjective) rating of the quality of thedata (1-10) as provided by the contributor. UNSODA can search for codes with a rating less, lessor equal, equal, greater or equal, or greater than the specified value.
Family. Conduct a search based on the soil family name by specifying the shortest character
string that uniquely identifies the targeted family name.
Series Name. Conduct a search based on the series name by specifying the shortest character
string that uniquely identifies the targeted family name. The List module contains all series
names in UNSODA.
Texture. Specify the exact textural classification according to the USDA-SCS triangle (cf.
Table 1). There should be a one-to-one correspondence between specified and targeted texture.
The List module displays the texture of most codes.
Structure. Conduct a search based on the soil structure by specifying the shortest character
string that uniquely identifies the targeted structure type.
Horizon. Enter a character string that matches part of the targeted horizon.
Location. Specify character string occurring in the names of a city, state, or country.
28

Chpt. 4. QUERY AND REPORT

29

Contact. Enter complete or partial family name to search for codes for which the named
individual may provide further information.
Keyword. Enter complete or partial keywords to identify codes with matching
characteristics. Examples are disturbed, undisturbed, horizontal, hysteresis, multiphase, salinity,
and tillage.
Field Wat. Ret.. Select a number from the list of methods to identify which method wasused to determine the water retention curve, 2(h), in the field.
Lab Wat. Ret.. Select a number from the list of methods to identify which method was used
to determine the retention curve, 2(h), in the laboratory.
Field Hydr. Cond.. Select a number from list of methods to identify which method wasused to determine the hydraulic conductivity, K(2) or K(h), or soil water diffusivity, D(2), in thefield.
Lab Hydr. Cond.. Select a number from the list of methods to identify which method wasused to determine the hydraulic conductivity, K(2) or K(h), or soil water diffusivity, D(2), in thelaboratory.
Field Ksat.. Select a number from the list of methods to identify which method was used
to measure the saturated hydraulic conductivity, Ks, in the field.
Lab Ksat.. Select a number from the list of methods to identify which method was used tomeasure the saturated hydraulic conductivity, Ks, in the laboratory.

5. PARAMETRIC MODELS FOR SOIL HYDRAULIC FUNCTIONS

Soil water retention and hydraulic conductivity/diffusivity data are often described withclosed-form analytical models. The use of mathematical expressions for the retention and hydraulicconductivity curves offers several advantages [van Genuchten et al., 1991]. They allow for a more
efficient representation and comparison of the hydraulic properties of different soils and soil
horizons, and facilitate the use of scaling procedures for characterizing the spatial variability of soil
hydraulic properties. Analytical models also permit more efficient data handling in unsaturated flow
models. They offer a way for interpolating or extrapolating to parts of the retention and hydraulicconductivity curves for which little or no data is available. Finally, closed-form expressions havebeen frequently used in conjunction with indirect methods for estimating soil hydraulic properties[van Genuchten et al., 1992].

The module MODELS of UNSODA facilitates the description of unsaturated soil hydraulicproperties with parametric models. An adapted version of the program RETC [van Genuchten et al.,1991] is used to optimize model parameters by fitting the closed-form mathematical expression to
the hydraulic data. In addition to the six models included in RETC, users can describe the data in
UNSODA with their own models. These alternative models must be included by the user in theoriginal FORTRAN program for RETC as discussed in section 6.4 and as shown in Appendix C.
Note that other optimization packages can also be used as long as the input/output structure conforms
to the C program for operating the Models section of UNSODA.

The default retention models in UNSODA are based on the retention functions by van
Genuchten [1980]

Se '

2& 2r
2s & 2r' [1% ("h)n ]&m30

Chpt. 5. PARAMETRIC MODELS

31

and Brooks and Corey [1964]

2 & 2r&8' ("h)
1
2s & 2r

Se '("h >1)("h# 1)

where Se is the effective degree of saturation or the reduced water content (0#S e#1), 2 r and 2 s are theresidual and saturated water contents, respectively, " is a parameter inversely related to the air entry
value (L-1), and 8, m, and n are parameters that affect the slope or the location of the inflection pointof the retention curve. The physical significance of these parameters should not be overestimated;
they are primarily of an empirical nature.

The hydraulic conductivity is described with the general models by Mualem [1976b] andBurdine [1953], respectively:
R

K(Se ) ' Ks Se

R

K(Se ) ' Ks Se

f(Se)
f(1)
g(Se)
g(1)

Se

2

dx
m h(x)

with f(Se ) '0Sewith g(Se ) 'dxm [h(x)]20

where Ks is the saturated hydraulic conductivity (LT-1 ) and R is a pore-connectivity parameter. The
expressions can be further refined through substitution of the previous retention functions, andintegration of the resulting expressions is based on some simplifying assumptions. Details regarding
the derivation and the resulting conductivity expressions can be found in van Genuchten et al.
[1991]. The van Genuchten retention function in conjunction with the conductivity models uses
either a flexible value for m or a value for m fixed m at 1-1/n for the Mualem model and 1-2/n for
the Burdine model. Together with the Brooks-Corey retention function this leads to a total of six
hydraulic models in conjunction with the Mualem and Burdine models. Table 3 schematically list

32

UNSODA 1.0

the default expressions in RETC (MTYPE#6) as well as possible user-specified models for UNSODA.
TABLE 3. Type of Retention and Conductivity Functions in UNSODAMTYPERetention Model

Conductivity Model1

van Genuchten (flexible m)

Mualem2

van Genuchten (flexible m)

Burdine3

van Genuchten (m=1-1/n)

Mualem4

van Genuchten (m=1-2/n)

Burdine5

Brooks-Corey

Mualem6

Brooks-Corey

Burdine7

User-specified models

.

..

.

..

(if applicable)

etc.
The hydraulic conductivity can be based on either the water content, i.e., K(2), or the soil
water pressure head (suction), i.e., K(h). Because the Richards equation for water flow inunsaturated soils is sometimes formulated with the soil water diffusivity, D(2), instead of thehydraulic conductivity, the use of D(2) is included as a third option. The soil-water diffusivity canbe readily based on a selected conductivity and retention models according toD(2) ' K(h)/C(h)where C(h)=-d2/dh is the soil water capacity. Expressions for D(2) are derived from the previously
given closed-form functions of 2(h) and K(h) or K(2). The hydraulic parameters in the six default
models in Table 3, or any user-specified model, are optimized with the program RETC.

Chpt. 5. PARAMETRIC MODELS33

RETC allows a maximum number of seven fitting parameters, the parameters are containedin the parameter vector b={2r,2s,",n,m,R,Ks}. Optimal values for the model parameters are foundby iteratively minimizing the residual sum of squares. The program allows optimization of: (i)retention data, (ii) conductivity or diffusivity data, and (iii) retention and conductivity or diffusivity
data. For a simultaneous fit of retention and conductivity or diffusivity data this sum is defined by
the objective function
N

M

O(b) ' j {[2i & 2̂i(b)]} % j { W1 W2 [Yi & Ŷi (b)]}2
2

i'1
i'N%1
^
where 2 and 2 are the observed and fitted water contents, respectively, Y and Y^ are the logarithms
i

i

i

i

of observed and fitted conductivity or diffusivity data, N is the number of observed retention data,
whereas M denotes the total number of data points (i.e., including K/D). The coefficient W1 assigns
a different weight to the entire K/D data set relative to the retention data while W2 is calculated
internally, it compensates for variations between retention and conductivity/diffusivity data due todifferences in the number and/or magnitude of the observations, or as a result of using other units.
The default value for W1 in UNSODA is unity. The relative conductivity is defined as

Kr ' K/Ks
The value for Kr varies between 0 and 1. Its use may be convenient for comparing conductivity
curves of different soils or if no reliable value for Ks is yet available. By fixing Ks to 1.0 in the
optimization procedure, the values for Y and ^Y are automatically considered relative values.
ii

It should be emphasized that many data sets in UNSODA exhibit considerable scatter; theobjective function for these cases may not converge to a minimum, and the optimization will thenbe terminated at a hard coded maximum number of 30 iterations. Furthermore, the minimum of theobjective function may not always be a global minimum and an incorrect solution of the inversion
problem is obtained. Nonunique solutions may also arise when the objective function represents avery flat response surface. This is typical when many parameters are optimized simultaneously using
data sets with little resolution (narrow ranges in 2 or h). Nonlinear parameter models such as thosein RETC require that initial parameters be specified. A judicious choice of initial parameters may

34

UNSODA 1.0

limit the occurrence of nonunique solutions, however, it is advisable to rerun the optimization usinga wide variety of initial estimates for b to ensure that a particular solution for b is indeed the "best"
possible.

Parameters can be excluded from the fitting process by fixing them, for instance, if

parameters are known independently or are highly correlated with other parameters. UNSODA has
a viewing routine to inspect the output file of RETC with statistical information regarding, which
can be used to assess the goodness of fit.

UNSODA allows three different ways to specify the initial estimates for the hydraulicparameters in the RETC code. First, the initial estimates can be based on soil texture using thevalues reported by Carsel and Parrish [1988]. A second option for providing initial estimates is theuse of retrieved values consisting of the elements of the vector b from the last optimization. Thirdly,
users can specify their own values for the elements in the parameter vector b. This option isrecommended for user-specified models, particularly for the first optimization; subsequent
optimizations may then use the second option for specifying initial estimates (i.e., retrieved values).
The user should be familiar with the selected hydraulic model to avoid mathematically unrealistic
initial estimates which could lead to run time errors during execution of the optimization program.
Carsel and Parrish [1988] provided average values of 2r, 2s, ", n, and Ks for 12 soil texturalgroups of the USDA-SCS classification system. Based on the textural classification for the soil
code, initial estimates will be displayed on the screen (Note that this is one of the reasons that it isimperative to specify the texture field exactly according the USDA-SCS system). The values for 2r,2s, ", n, and Ks are shown in Table 4. Additional estimates for the remaining parameters m and R are
generated internally. They are independent of texture and based on the selected default model:
1 van Genuchten & Mualem (flexible m): m=1-1/n, R=0.5
2 van Genuchten & Burdine (flexible m): m=1-2/n (n>2) or m=0.5 (n<2), R=2
3 van Genuchten & Mualem (fixed m=1-1/n): R=0.5
4 van Genuchten & Burdine (fixed m=1-2/n): n=2.25 (if n<2 in Table 4), R=2

Chpt. 5. PARAMETRIC MODELS

35

5 Brooks-Corey & Mualem: m=1 and R=0.5 (8=n)
6 Brooks-Corey & Burdine: m=1 and R=2 (8=n)

TABLE 4. Default Initial Estimates of Selected Parameters in Models for
Unsaturated Hydraulic Functions [after Carsel and Parrish, 1988]
Textureclass
Sand
Loamy sand
Sandy loam
Loam
Silt
Silt loam
Sandy clay loam
Clay loam
Silty clay loam
Sandy clay
Silty clay
Clay

2r

2s

"

n

Ks
cm/d

2.68
2.28
1.89
1.56
1.37
1.41
1.48
1.31
1.23
1.23
1.09
1.09

712.80350.16106.08
24.96
6.00
10.80
31.44
6.24
1.68
2.88
0.48
4.80

1/cm
0.045
0.057
0.065
0.078
0.034
0.067
0.100
0.095
0.089
0.100
0.070
0.068

0.43
0.41
0.41
0.43
0.46
0.45
0.39
0.41
0.43
0.38
0.36
0.38

0.145
0.124
0.075
0.036
0.016
0.020
0.059
0.019
0.010
0.027
0.005
0.008

6. DATABASE PROGRAM

6.1. Software

The different types of data in UNSODA are stored in 43 tables, which were created with
KnowledgeMan® (version 2.5). The tables were designed according to principles of relational
database design to minimize duplication and to reduce the size of the tables. Formal database design
is further discussed by Date [1986] and Walters [1987], among others. Each table in UNSODA
contains a key field code, which is used by UNSODA to access pertinent records during a query
operation. Because of the large number of entries, and the disparity in the number of data points
between soil codes, a special "pointer table" was created for each tabular data table to locate the datafor individual soil codes. Comments regarding the measurement of hydraulic properties wereassigned numerical values, which are tied to separate tables containing the actual comments. Thisapproach avoids repetition of long character strings for each code, e.g., field measurements on
different horizons, or identical laboratory experiments on soil cores.

A database management program to store and access the data was written in Microsoft® C
version 7.0 using the KC library from Micro Data Base Systems. This library contains all necessaryfunctions to access and manipulate the above database tables. The program consists of 42 modules
with a total of approximately 11,000 lines of code. Several special scrolling and edit routines weredeveloped for UNSODA. Furthermore, the program was linked to the Fortran program RETC for
fitting the parametric models by van Genuchten or Brooks-Corey to 2(h) and the models by Mualem
and Burdine to the K/D data.

6.2. Description of Menu Structure

The structure of the screen menus and the working of UNSODA will be outlined in thissection. A general overview is given of all the current modules of the database program such as data
entry and editing, queries, and the use of hydraulic models.
36Chpt. 6. DATABASE PROGRAM

37

The operation of UNSODA is generally based on the code or record number; as was
discussed earlier, a code number is assigned to each data set for a particular soil material. The data
for the soil can be determined in the laboratory or in the field on a disturbed or "undisturbed"
medium. Although the measurement of various properties may be done on different samples(textural and chemical analysis, hydraulic data from in situ or laboratory measurements), it isassumed that these samples are representative for the same type of porous medium.

The

management program of UNSODA can perform various tasks on the fields of one or more records.
In this section we will discuss the different levels of the menu system. A list of menus is given in
Appendix D.

Four distinctive modules are offered in the Main Menu (cf. section 2.3). Users who want to
add their own data or who wish to modify existing data have to select module 1 (DATA ENTRY AND
EDIT). Module 2 (QUERY AND REPORT GENERATION) allows a user to search for records that match
the query fields, selected tabular data or the complete information for matching codes can be written
to an output device. Module 3 (MODELS) concerns the use of closed-form expressions for describing
selected hydraulic data for a specified code. This module is based on the RETC program [vanGenuchten et al., 1991] as was explained in Chapter 5. Finally, several operations on the codes andtables of UNSODA can be done with module 4 (UTILITIES); codes can be deleted or code numberschanged, data tables can be reindexed after their contents have been modified, and the contents offiles in a directory to be specified can be viewed.

1. DATA ENTRY AND EDIT
The Data Entry menu appears with six selections. Create (1) is selected when a "complete" data
set is to be entered for a new soil code, Append (2) and Delete (3) allow the addition or deletion of
tabular data for an existing code, Edit (4) is chosen when any type of data is to be changed or deleted
for an existing code, Conversion (5) allows the automatic change of original units, for data entered,to standard units in UNSODA by defining multiplication factors, and List (6) will display a table of
all codes in UNSODA with their series name and texture.

38

UNSODA 1.0

1.1. Create a New Soil Code and Enter Data
The Create selection requires that a new unique code number be entered in the Specify New
Code # menu for each (soil) record for which data are to be entered. The code numbering isarbitrary; however, it was arbitrarily chosen to use multiples of 10 for code numbers of an
independent data set and to increment the last code number by 1, if there is a similarity between thepreviously added code and the record to be created. This similarity may consist of data being fromthe same experiment but obtained from a different soil layer or a change in experimental conditions(temperature, salinity). The two numbers for the new code according to this convention are shownon the screen and may be selected by pressing <N> (new) or <P> (previous), respectively. Users
may want to use their own numbering convention, for example to optimize the query and report
procedure for this purpose; press <I> to input an arbitrary number. Once a code number is provided,
the actual data entry can start. The input should be prepared according to Chapter 3, an example isgiven in Appendix B. The user may want to define conversion factors to directly enter data withunits differing from the standard UNSODA units.

The Descriptor Data 1 menu allows entry for fields involving soil classification, location, andclimate. It is important that a series name be given, preferably according to an official classification
system; otherwise a name based on the location should be chosen to uniquely identify the code(s).
The texture name is according to the USDA-SCS system. Data are first typed in, or can be
overwritten, by moving from field to field using the <Enter> or <5> key. Pressing the <F10> key
for the first time allows one to edit the data for all fields on the screen. Press the upper or lower caseletter corresponding to the field that needs changing. To continue data entry, move on to the nextscreen by pressing <F10> again. Leave the data entry menu without any data allocation for this code(its number will be disregarded) by pressing <Esc>. The use of <F10>, <Esc>, <Enter>, and<LETTER> keys is similar for other screens.

The Descriptor Data 2 menu allows further background information to be entered. Note that inversion 1.0 of UNSODA, no data allocation is possible unless some type of (fictitious) information

Chpt. 6. DATABASE PROGRAM

39

is provided for at least one of the fields from Descriptor Data 2. The Soil Properties menu contains
fields for numerical data of basic soil properties. Since a fairly wide range of soil properties is
included it is unlikely that there are data for all fields. For missing data no value should be entered.
Note that only one value can be entered for each field, the user may need to average multiple datato get a value most characteristic for the soil material. Upon completion, the user will be asked
whether the new code should be included in UNSODA.

If the data entry session for the code is continued; the Methodology menu appears for the
purpose of entering comments on the measurement of water retention (Field and Lab 2(h)),
hydraulic conductivity (Field and Lab K/D), saturated conductivity (Field and Lab Ksat), andgeneral field and laboratory procedures (Field and Lab Comment). These comments can beselected from a list with existing comments. Existing comments may be viewed using the up <8>and down <9> arrow keys. The number of the displayed comment is shown on the left side of thescreen while the initially displayed or selected comment number is shown on the right-hand side.
If there is no appropriate comment available, a new comment can be added by copying a similarcomment and editing it to obtain the desired formulation or by bypassing the copy feature and byformulating a new comment from scratch. It is generally not advisable to edit an existing comment
without copying it first, as the comment may also be used for other codes. Select "no comment" ifdata will be entered but if the method of determination is unknown and select "NA" if no data exist.
A list of Methodology comments is provided in Appendix E.

The Tabular Data Type menu will automatically appear after quitting the menu on methodology
comments. There are 11 types that can be selected, viz.: Particle Size Distribution, Dry Aggregate
Size Distribution, Mineralogy, Field 2(h), Field K(2), Field D(2), Field K(h), Lab 2(h), Lab
K(2), Lab D(2), and Lab K(h). For hydraulic data the user should specify whether the data are fora drying or wetting branch of the retention curve; only one type of wetting and drying branch can beentered for each code number.

40

UNSODA 1.0
The entry of data pairs is fairly straightforward, using the <F2> key for changes in entered data,the <Esc> key to return to the Tabular Data Type menu without saving the tabular data, and the<F10> to finish entering data with the option to append the data for this code to the appropriate
UNSODA table for all codes.

Upon completion of the data entry, the user may want to go to the UTILITIES module to take thegeometric average of multivalued tabular data (i.e., one independent value has more than one
dependent value) and to sort tabular data, or to reindex the pointers for the tables.

1.2. Append Tabular Data for an Existing CodeThe Append option is used to add tabular data to an existing soil code. A number of an existingsoil code needs to be entered in the Append Tabular Data menu. The number may be selected fromthe list of codes in UNSODA — press <Ins> to display the list, move the cursor to the desired code,and press <Enter> — or a number can be typed in by the user. After the type of data is specified
through the Tabular Data Type menu, UNSODA will display the appropriate tabular data screen toenter the independent and dependent variables. Similar key strokes are used as in the Create routine.
The screen also contains the number of data pairs already stored in UNSODA for this code number;use the Edit option to alter existing data.

1.3. Delete Tabular Data for an Existing CodeUpon choosing the Delete Tabular Data option, the user is prompted to provide a code number
on the Tabular Data to be Deleted menu; again, this can be done by typing in a code number or bymaking a selection from the code list. Subsequently a list with types of tabular data appears on the
Tabular Data to be Deleted menu, select the type from which some or all data pairs are to be deleted.
For hydraulic data a wetting or drying cycle needs to be specified. Individual observations aremarked (*) for deletion by typing the displayed number (#), press <F10> when the marking ofrecords is finished. The user has to confirm deletion of the marked records.

Chpt. 6. DATABASE PROGRAM

41

1.4. Edit Any Data for an Existing CodeThe screen Edit Data prompts the user to specify the code number for which data are to beedited. In the Select Type of Data menu a choice can be made between:

General Information Data. Select this option if descriptor data and basic soil properties must
be changed. The selection accesses the Descriptor Data 1, Descriptor Data 2, and Soil Properties
menus. Press the letter for the field to be edited. The user is asked whether the changes should besaved.
Tabular Data. For the hydraulic data first specify if data from the wetting, <W>, or drying,<D>, curve need to be edited. The data pair to be edited is selected by typing its number (1<#<9).
Possible additional data pairs can be viewed by using the arrow keys (<8> and <9>).
Methodology. Comments on field and laboratory methodology can be edited by selecting the
Methodology option. The appropriate comment is selected similarly as in the Create routine.

1.5. Conversion Factors for Dimensions
Selection of Conversion allows a user to set all conversion factors to the default value of 1 or
to enter different values for selected fields with the Conversion Factors for Dimensions menu. Incase of the latter choice, a list with 18 conversion factors appears. The "standard" units for
UNSODA are given in parentheses. The use of the conversion feature allows the entry of "raw" data
for fields having units that differ from the standard UNSODA units. The data will be automaticallymultiplied by the conversion factor, which has the dimension of standard UNSODA units over "raw"data unit. Conversion factors have to be specified for each session of UNSODA, otherwise default
unit values will be used.

1.6. List Codes and Series Names
The final option of the data entry menu lets the user go through the contents of UNSODA,
displaying code numbers with corresponding series name and texture, using the List menu.

42

UNSODA 1.0

2. QUERY AND REPORT GENERATIONThe second and probably most utilized module of the main menu concerns the search for codesthat meet query specifications for all selected fields and the reporting of database information to an
output device. The Data to be Searched menu offers the choice to: (1) query for one or more fields
and retrieve Specific Codes that match specifications, these specifications are subsequently written
to an output device; (2) report contents of All Codes in UNSODA to an output device, i.e., the queryfeature is bypassed; (3) query as under (1) but only report Specific Tabular Data to an output
device; and (4) display the contents of UNSODA, again, with List Codes.

2.1. Specific Codes
Data for one or more fields to be searched are specified with the Specify Search Fields menu.
To conduct a search, move the cursor to the name of a field to be searched, set the field by pressing<Enter> — this is a toggle key that can also be used to "unset" or disable search fields, type thesearch string, press <Enter> again. Additional search strings can be specified in this way, or the
search can be started by pressing <F10>. For alphabetical search fields the program will try to matchthe specified character string with the data for all codes in UNSODA for the designated field. In casetexture is used as the search field, codes will not be found unless the search field completely matches
the texture entry in UNSODA, and vice versa. Identical names as in the USDA-SCS textural triangle
should therefore be used for the texture field. For example, if "sand" is specified as a query in the
texture field, no codes with "sandy loam" as texture will be retrieved. For fields other than texture,a less restrictive search can be conducted by specifying an incomplete entry.

Queries for comments on the methodology are specified with the current table of comments.
For numerical values (code number or rating), the program can search for codes with values greater
than, equal to, or lesser than the specified numerical values. If the code number is a search field, thescreen Code: will appear to specify the code range of interest with respect to the specified value (i.e.,>, $, =, #, or <). A similar screen, Rating: , will appear if rating is selected as a search field. Aftercompletion of the search the Device Settings menu will be displayed. Data for the codes that match

Chpt. 6. DATABASE PROGRAM

43

the search profile can be reported by first selecting the output device (the <Enter> key again acts asa toggle switch): (1) screen, (2) disk, or (3) printer; and then (4) compile the report. The screen
option allows the user to scroll through the complete contents of a matching code, using <9> and<8>, or to move to different matching codes, using <PgDn> and <PgUp>. The database contents
for matching codes can be written to a file on a floppy or hard disk with the disk option; the user willneed to provide a file name and, if desired, the directory on the Filename menu. Similarly, a hard
copy can be obtained by selecting the printer option. The user should check printer requirements
for this option, and the program may be exited to specify the device.

2.2. All Codes
No search will be conducted for this option and the program will directly go to Device Settings
menu; output can be generated in the same manner as for Specific Codes. This selection is probably
most useful for writing the database contents to the screen and perusing the data.

2.3. Specific Tabular Data
Most users of UNSODA are likely interested in hydraulic data per se, in which case there is noneed for general information or basic soil properties. The Specific Tabular Data option lets theuser write specified tabular data sets to an output device after a search has been conducted. Although
the Specific Tabular Data option is essentially the same as the Specific Codes option; the user
must specify after the search is completed which data are to be written to an output device from theSelect Table to Print From menu. Because the output is limited to tabular data, less editing isrequired before the data can be used as input to other application software (e.g., numerical simulationof soil water flow, research of indirect methods for estimating unsaturated hydraulic properties).

2.4. List Codes
Use the List screen to view code numbers, series name, and soil texture.

44

UNSODA 1.0

3. MODELS
This module needs to be selected for describing the unsaturated hydraulic data in UNSODA.
The Models menu offers the option to (1) update model names and numbers (Add/Delete Model
Name), (2) describe hydraulic data with any of these models using the optimization program RETC
as outlined in Chapter 5 (Execute RETC Optimization), or (3) view any file in the default directory(View RETC Results or any other File).

3.1. Add/Delete Model Name
A list of all current parametric models in UNSODA will be displayed on the Add/Delete Model
screen. Typically only the six RETC models will be shown [van Genuchten, 1991]. A name can bedeleted from the list by pressing <F9> whereas a name can be added by first pressing <F10> and thentyping a name. The number (MTYPE) to identify the model with this name in the program
RETC4.FOR (section 4.4). The addition or deletion of model names is of little consequence as longas the RETC4.FOR program does not reflect them.

3.2. Execute RETC Optimization
The user should know the code number and the precise type of hydraulic data to be modeled.
The code number is specified with the Code to be Modeled screen; the number can be typed in or
selected from the List routine by first pressing <Ins>. The retention and conductivity/diffusivity dataneed to be from the same type of wetting or drying cycle; this is specified on the Hydraulic Curve
screen. The hydraulic model to be optimized to the data with the RETC code is selected from theSelect Models for RETC menu. A choice can be made with the Type of Hydraulic Data menu whichdata should be optimized by RETC: (1) Retention and Conductivity/Diffusivity Data, (2)Retention Data only, or (3) Conductivity/Diffusivity Data only. Depending on the preference,
field or laboratory data need to be specified and the type of K/D data (i.e., K(h), K(2), or D(2)).
An important part of the optimization is the selection of the initial estimates, this is done on theInitial Parameters screen. As explained in Chapter 5, the initial estimates can be specified in threeChpt. 6. DATABASE PROGRAM

45

different ways. Estimates for the default RETC models based on the texture of the soil code using
the data from Carsel and Parrish [1988] are shown as the suggested <S> parameters. Retrieved <R>
values are based on the results of the last optimization. Users <U> can also specify their own initialvalues for the model parameters. This last option will normally be needed for user-specified models(MTYPE>6). Note that the parameter names appearing on the screen correspond to those of theseven-parameter models in RETC, their meaning may be quite different for other hydraulic models.
Each parameter can be fixed, i.e., the parameter remains equal to its initial estimate during the entire
optimization. After the Summary of Options screen appears, which may be used for debugging
purposes, the Output screen requires specification of a file name and, if desired, a path to anotherdirectory. The fitting results are not automatically written to UNSODA.

The results of the RETC execution can be inspected with the View Model Output screen. The
user can now decide whether or not to (i) perform another optimization, (ii) write the model results
to UNSODA, or (iii) abandon the optimization. Note that run-time errors may easily occur duringexecution of RETC4.FOR because of incorrect or incomplete data, poor initial estimates, or an
inadequate model. The user will have to make a decision whether and how the optimization can be
improved, after which UNSODA can be started again. Upon review of the output file, the results
can be stored in UNSODA using the Store Model Output menu. The results are parameter values(2r, 2s, ", n, Ksat, R, m), type of mathematical model, type of hydraulic data, sum of squares, and theregression coefficient for goodness of fit.

3.3. View RETC Results or any other File
The last option of the Models module allows the user to view files in the directory of thedatabase, among them are files of the output of the RETC optimization.

4. UTILITIESThe final choice of the main menu is the Utilities module for updating the database contents andimprove the efficiency of the table structure.

46

UNSODA 1.0

4.1. Delete CodeCodes can be selected for deletion through the Delete Code menu by specifying a code number(either by typing in the number or choosing it from the list of codes). The code number and all theinformation pertaining to the code will be removed from UNSODA. Subsequently, the program willautomatically reindex the tables.

4.2. Change CodeThis option allows the renumbering of codes. The Change Code menu asks for the old code
number (from a list or direct entry) and a new number. Note that this is not a copy procedure, uponcompletion, the old number will no longer exist.

4.3. List Codes
Use this command to list all code numbers in UNSODA with, if available, their series name andtexture.

4.4. Reindex Data Tables
With the Reindex menu the pointer tables for data in UNSODA can be updated. Reindexing isnecessary if (external) tabular data are used in the management program. Reindexing should also
be done immediately after installation of UNSODA. Note that UNSODA cannot work correctly if
the pointers do not correspond to the correct tabular data (cf. section 6.3). Further use of thedatabase without reindexing may corrupt the data tables.

4.5. Sort Tabular Data
Tabular data can be sorted using the Sort Tabular Data menu. The code number and the data
type need to be specified. Data will be sorted in ascending order and the geometric mean will betaken of data pairs with the same value for the independent variable (i.e., pressure head for retention
and pressure head or water content for K/D). It is assumed that the data obey a lognormal
distribution.

Chpt. 6. DATABASE PROGRAM

47

4.6. Check Pointer Tables
The Pointer Table Checker detects "gaps" and "overlaps" in the pointers of tabular data. In casean error is detected and reindexing does not rectify the problem, the user should read in an older,correct version of the relevant data table.

4.7. View Text or Data Tables
The View Text or Data Tables routine allows one to read ASCII files in the default directory or
any other directory specified by the user, while running the database program. Press <F1> for more
information on using the different keys.

6.3. Table Structure

The data in UNSODA are stored in a variety of data tables within the KMAN databasesystem. The tables are structured for flexibility and efficiency in data storage and manipulation fora wide variety of different properties and characteristics. Table 5 shows a general database structure
for different types of tables, the first column contains the general table name, the second column
describes the format including the length of character strings, and the third column describes the typeof data (fields) that follow the format of the general table. Although real values for numerical data
appear to have only a limited number of decimal places (typically 5) during I/O operations, thenumber of significant digits that can be stored in UNSODA is considerably higher. The actual
number is hardware dependent.

48

UNSODA 1.0
TABLE 5. Table Structure of UNSODA

Table Name

Data Format

Comment

LCOMMENTSCOMMENT
MINERAL

character (800)character (80)character (20)realintegercharacter (65)integer
integer
integercharacter (1)integercharacter (60)character (25)character (6)integer
integerreal
realinteger
integer
integer
integer
integer
integer
integer
integer
integer
integercharacter (35)character (25)character (50)character (30)integer
real
real
real
real

Long comment for field or laboratory procedures
Short comment for measurement of hydraulic properties
Mineral name
Mass fraction of mineral
Number of model for unsaturated hydraulic properties
Name of model
CODE: record number for pointers of hydraulic functions
BR: beginning of data for record in a hydraulic table
ER: end of data for record in a hydraulic table
DCURVE: drying (D) or wetting (W) curve
CODE: record number
LOCATION: names of city, state or province, and country
SITE: more detailed description of location
HORIZON: name of soil horizon
LOW: upper position (minimum depth) of horizon
HIGH: upper position (minimum depth) of horizon
D1: independent variable of hydraulic data table
D2: dependent variable of hydraulic data table
CODE: record number
FWATRET: comment number for field water retention
LWATRET: comment number for lab water retention
FHYCOND: comment number for field hydraulic conductivity
LHYCOND: comment number for lab hydraulic conductivity
FKSAT: comment number for field saturated conductivity
LKSAT: comment number for lab saturated conductivity
FCOMMNUM: comment number for field procedures
LCOMMNUM: comment number for laboratory procedures
CODE: record number
STRUCTUR: description of soil structure
TEXTURE: soil texture
FAMILY: name of soil family
SERIES: name of soil series
CODE: record number
ANNRAIN: amount of annual rain
AVTEMJAN: average temperature in January
AVTEMJUL: average temperature in July
DEPTH: depth of ground-water table

MODELS
RAW_PTRLOCATION

RAW_DATAMETHODO

CLASSIF

CLIMATEChpt. 6. DATABASE PROGRAM

49

TABLE 5. Continued
Table Name

Data Format

Comment

SOILPR1

integer
real
real
real
real
character (240)integer
real
real
real
real
integer

CODE: record number
BD: bulk density
POROSITY: porosity
KSAT: saturated hydraulic conductivity
THSAT: saturated water content
COMMENT: information on basic soil properties
CODE: record number
PARTDEN: particle density
ORGMAT: organic matter
CEC: cation exchange capacity
FEALOX: Fe and Al oxide content
CODE: record number for pointer table of particle- and aggregatesize distributions and mineralogy
BR: beginning of data for a particular record
ER: end of data for a particular record
SIZE: particle size
CUMFRAC: cumulative mass fraction
CODE: record number
MODEL: model number of unsaturated hydraulic function
METHOD: K(h), K(2) or D(2) data
THR: 2r in RETC
THS: 2s in RETCALPHA: " in RETC
N: n in RETC
KS: Ksat in RETC
M: m in RETC
L: R in RETCRSQUARE: r2 for regression of fitted and observed data
SSQ: sum of squares for regression
DTYPE: field or laboratory data
DCURVE: drying (D) or wetting (W) curve
CODE: record number
PH: pH
ELECTR: total electrolyte level
SAR: sodium adsorption ratio
ESP: exchangeable sodium percentage
EC: electrical conductivity

SOILPR2

SOILPR2
PDM_PTR

PSD
MODPARAM

SOILPR3

integer
integerreal
realinteger
integer
integer
real
real
real
real
real
real
real
real
real
integercharacter (1)integer
real
real
real
real
real

50

UNSODA 1.0

TABLE 5. Continued
Table Name

Data Format

Comment

TXTHYPRM

character (25)TEXTURE: Textural classification for initial values of parameters
in hydraulic models
THR: 2r in RETC
THS: 2s in RETCALPHA: " in RETC
N: n in RETC
KS: Ksat in RETC
CODE: record number
PUB: published literature on data and measurement
CONTACT: contact for further information
COMMENT: topology, geology, or agriculture at site
RATING: quality rating
RNAME: name of rater
DATE: approximate date of measurements
KEYWORD: keywords characterizing experiment
SIZE: equivalent aggregate diameter
CUMFRAC: cumulative mass fraction
ID
DESC: text for help comments

GENINFOPSD_DASD
HELPTBL

real
real
real
real
real
integercharacter (240)character (240)character (480)integercharacter (40)character (8)character (111)
real
real
real
character (1200)

Table 5 pertains to the general structure. The data itself are stored in files with extension ITB
as shown in Table 6. An effort was made to combine similar fields that are infrequently used in thesame file to increase the efficiency of UNSODA. The Methodology comments consist of a tablewith numbers for all eight different comments for each code (METHODO.ITB), i.e., the integers in
Table 5. These numbers, in turn, are linked to actual comments in eight different files (e.g.,
FHYDRCON.ITB in Table 6) with the LCOMMENT or SCOMMENT structure.

Chpt. 6. DATABASE PROGRAM

51

TABLE 6. Files for Data Tables in UNSODA
File Name

Table Name

Description of Field

CLASSIF.ITB
CLIMATE.ITB
DASD.ITBFHYDRCON.ITBFKSAT.ITBFLDCOMM.ITB
FRAWHK.ITB
FRAWHT.ITB
FWATRET.ITBFRAWTD.ITBFRAWTK.ITB
GENINFO.ITB

CLASSIF
CLIMATEPSD_DASDSCOMMENTSCOMMENTLCOMMENT
RAW_DATA
RAW_DATASCOMMENT
RAW_DATA
RAW_DATA
GENINFOHELPTBL.ITB
LABCOMM.ITB
LHYDRCON.ITB
LKSAT.ITB
LOCATION.ITB
LRAWHK.ITB
LRAWHT.ITBLRAWTD.ITB
LRAWTK.ITB
LWATRET.ITB
METHODO.ITBHELPTBLLCOMMENTSCOMMENTSCOMMENT
LOCATION
RAW_DATA
RAW_DATA
RAW_DATA
RAW_DATASCOMMENT
METHODO

MINERAL.ITB
MODELS.ITB
MODPARAM.ITB
PSD.ITB
SOILPR1.ITB
SOILPR2.ITB
SOILPR3.ITB
TXTHYPRM.ITB

MINERAL
MODELS
MODPARAM
PSD
SOILPR1
SOILPR2
SOILPR3TXTHYPRM

Soil structure, texture, family, seriesRain, temperature, depth of ground water table
Dry aggregate-size distribution
Comment on field K/D measurement
Comment on field Ksat measurement
Comment on field procedures
Field K(h)Field 2(h)Comment on field 2(h) measurement
Field D(2)Field K(2)Publication information, contact, comment, rating, rater,
date, keyword
Help comments for UNSODA menus
Comment on laboratory procedures
Comment on laboratory K(h) measurement
Comment on laboratory Ksat measurement
Location, site, horizon, depth
Laboratory K(h)Laboratory 2(h)Laboratory D(2)Laboratory K(2)Comment on laboratory 2(h) measurement
Comment numbers for laboratory and field measurements(SCOMMENT and LCOMMENT)
Mineralogy
Number and name of hydraulic model
Optimized hydraulic model parameters (2r,2s,",n,m,R,Ks)
Particle-size distribution
Bulk density, porosity, Ksat , 2sat, comment
Particle density, organic matter, CEC, Fe and Al
pH, concentration, SAR, ESP, EC
Soil-texture based initial estimates for soil hydraulic models

52

UNSODA 1.0
Tabular data are stored sequentially, the beginning and end of a sequence is denoted withpointers for each record (code). This procedure allows optimal use of the tables regardless of thenumber of codes that actually possess a particular type of data, or the number of data pairs. Below
is an example of a pointer table for laboratory D(2) data. The first column in Table 7 contains thecode number, the second and third columns denote the beginning (BR) and end (ER) of the data inthe data table for that particular code, whereas the fourth column indicates a drying (D) or wetting(W) curve. Note that code 1340 contains ten D(2) data (drying curve), these are contained in thedata table LRAWTD.ITB and are shown in the last two columns of Table 7.
TABLE 7. Illustration of Pointer Table for Laboratory D(2) Data

etc.

CODE

BR

ER

Wet/Dry

1340
1341
1342
1350
1351
1352
1420
1430
1450

1
11
21
31
41
51
61
69
74

10
20
30
40
50
60
68
73
78

D
D
D
D
D
D
W
W
D

2

D(2)

0.38
0.35
0.33
0.31
0.29
0.25
0.23
0.20
0.14
0.13
0.38

52742.00
1826.00
227.48
69.76
38.44
14.87
11.83
9.03
5.67
4.46
953.00Chpt. 6. DATABASE PROGRAM

53

Pointer tables for the particle- and aggregate-size distributions, the mineralogy, and thehydraulic data are given below. Whenever (external) tabular data are imported, the pointer tableshould be reindexed to correctly link general information and tabular data to the soil codes. This isdone through the Utilities module of the main menu.

TABLE 8. Pointer Tables for Tabular Data
Table Name

Description

DASDREC.ITBMINREC.ITB
PFHK.ITB
PFHT.ITBPFTD.ITBPFTK.ITB
PLHK.ITB
PLHT.ITB
PLTD.ITB
PLTK.ITB
PSDREC.ITB

Dry aggregate-size distribution
Mineralogy
Field K(h)Field 2(h)Field D(2)Field K(2)Laboratory K(h)Laboratory 2(h)Laboratory D(2)Laboratory K(2)Particle-size distribution

6.4. Models

Additional models, with MTYPE>6 as shown in Table 3, can be included in the Fortranprogram RETC4.FOR by the user; this program needs to be recompiled. The modifications should
be in a manner consistent with the default models so that the input and output conform to therequirements of the "C" program for interaction with UNSODA and the Fortran program for the
optimization. Appendix C contains parts of the program RETC4.FOR that are relevant for userspecified models. The lines that are dependent on the hydraulic model are marked by asterisks, eachpart is followed by some brief comments. UNSODA prepares the input file RETC.IN based onmenu selections by the user and the hydraulic data stored in UNSODA for the selected code. The
same input file can be used for models that are not included in RETC. An outline of RETC.IN isgiven in Table 9.

54

UNSODA 1.0
TABLE 9. Outline of the Input File RETC.IN

Line

FormatVariable

Description

1
2
3

A60
A60
A12

TITLE
TITLE2OUTFIL

4

8I8

MTYPE
METHOD

Number of soil code selected for modeling.
Series name for selected soil code.
Name of file to which results of optimization will be written. The
default drive is the same as for UNSODA, pathways for other (disk)
drives can be included in OUTFIL (cf. A:RETC.OUT).
Type of model to be fitted to the data.
Type of conductivity/diffusivity data to be entered, i.e., K(2), K(h),or D(2). The log transforms of these data will be used during the
optimization.
Input variable for type of fitting. For optimization of 2(h) and K/D,
only 2(h), only K/D, or no data KWATER equals 0, 1, 2, or 3,
respectively.
Initial estimates for the model parameters. The parameter vector isgiven by b = {2r,2s,",n,m,R,Ks}. Different parameter vectors can be
defined for models used in conjunction with UNSODA which are
not included in RETC as long as the order of the elements of b isconsistent.
Number of 2(h) data.
Number of K(h) data.
Number of K(2) data.
Number of D(2) data.
Indices for the coefficients B(I) indicating if the Ith coefficient is an
unknown and must be fitted to the data (INDEX(I)=I) or if there isno need to fit the coefficient because it is assumed to be known
independently.
Heading for lab and/or field hydraulic data.

KWATER

5

7F11.4

6

8I8

7

8I8

IT
IHK
ITHK
ITHD
INDEX(I)

8

A

JUNK

If IT>0 (2(h) data)
2F11.4IT lines
If IHK>0 (K(h) data)
2F11.4IHK lines
If ITHK>0 (K(2) data)
2F11.4
ITHK lines
If ITHD>0 (D(2) data)
2F11.4ITHD lines

B(I)

X(I)
Y(I)

Pressure head, h.
Volumetric water content, 2.

X(I)
Y(I)

Pressure head, h.
Hydraulic conductivity, K.

X(I)
Y(I)

Pressure head, h.
Hydraulic conductivity, K.

X(I)
Y(I)

Volumetric water content, 2.
Soil water diffusivity.

Chpt. 6. DATABASE PROGRAM

55

Users ordinarily need not be concerned with this file since it is generated automatically by
the database program. Other common variables that may need to be adjusted are given in Table 10.
TABLE 10. Miscellaneous Key Parameters in RETC4.FOR

NWC

Number of water retention data (=IT)

NOB

Total number of observed hydraulic data, i.e., retention and conductivity/diffusivity data. Initially
NOB is set to 0, it is then calculated as IT+IHK or IT+ITHK or IT+ITHD.

KITER

Improved estimates for the unknown coefficients are printed during the first KITER iterations of
the optimization. Results for the last iteration are always printed. UNSODA uses KITER=4 as
its default value.

MIT

Maximum number of iterations. MIT=30 is the default value.

W1

Weighting coefficient in objective function to give the relative weight of K/D data with respect
to retention data. The default value for W1 is 1.

7. EXAMPLES

The purpose of this chapter is to familiarize readers with the database management programby taking the user of UNSODA step-by-step through three examples. The examples are illustrated
in this manual using screen output. The number of screen that is shown will be given in parentheses
in the text. The examples provide a convenient introduction to the program and also demonstratepotential applications of UNSODA.

7.1. Data Entry and Edit

Assuming that data have been prepared according to Chapter 3, an example to consider thecase illustrated in Appendix B with retention and conductivity data from the field, and retention data
as well as some other properties determined in the laboratory is presented. After starting UNSODA
by typing "start" and passing through the introductory screen by pressing any key, the Main Menu
(1) appears. The first option is selected by pressing <1> or <Enter> and the Data Entry menu (2) will
be displayed. For this example, a value for Ks will be entered with units of cm/h. To let UNSODA
convert this automatically to the standard unit (cm/d) upon entry press <5> and select <2> from theConversion Factors for Dimensions menu (3) to reach the screen with Conversion Factors for
Dimensions. Next, press <F> and type the value 24.00 h/d (4). Return to the Data Entry menu bypressing <Enter> and <Esc> and select <1> to reach the Specify New Code# screen (5). There are
two suggested numbers on the screen based on the last code number that was created, say 4960. If
the data are unrelated to those in code 4960, a completely new set of code numbers can be started
by pressing <N>, i.e., the code number will be 4970. If the data are somehow related to those ofcode 4960, e.g., the next horizon of a soil profile, then the suggested number 4961 is obtained byadding 1 to the previous code (<P>). The user can specify an arbitrary number as well (<I>). For
this example by pressing <N>, the Descriptor Data 1 screen (6) appears. Information according toAppendix B can now be typed. Move from field to field in the entry mode by pressing <Enter>.
When data entry is completed or if a mistake was made (no editing is possible in the entry mode),press <F10>. To correct, for example, a misspelled series name Troop (6), press <A> and a new56

Chpt. 7. EXAMPLES

57

set of keys can be used for cursor movement as shown at the bottom of the screen (7). After theseries name has been corrected, press <Enter> and <F10> to enter data in the Descriptor Data 2
screen (8). Upon completion of data entry, press <F10> twice and the Soil Properties screen (9) isreached. Notice the value of the conversion factor at the bottom of the screen for each field. Whena saturated conductivity value of 7.13 cm/h is specified, a value of 24 h/d is displayed for theconversion factor. The value for Ks will automatically be recalculated to 171.4 cm/d after pressing<Enter> (10).

The <F10> key can be pressed at any time for corrections. Pressing <F10> again will elicita response from the user whether or not this code should actually be established (11). After
responding with <y>, the program reaches the Methodology menu (12). To specify the procedurefor determining, for example, the saturated conductivity in the laboratory, press <6>. The comments
currently used can be viewed by moving through the Lab Ksat Comments menu. The initial (ninth)comment (13) is not applicable and the cursor is moved up to the first comment with the <8> key
to reach the first comment. This comment is selected by pressing <S> (14). The entry of
Methodology comments can be discontinued by pressing <Esc> to go to the Tabular Data Type menu
(15). Press <8>, for instance, to enter laboratory retention data; specify that the data are from thedrying curve (16) and start typing data with the Lab 2(h) screen (17). Press <Enter> each time anumber has been entered. Assuming that a mistake was made in the sixth row (17), press <F2> and<6> to type the correct data pair with the keys shown at the bottom of the screen (18), correct the
mistake, and press <F5> to continue data entry. Upon entry of all data press <F10>, <y>, and <Esc>.

Assuming that additional retention data have become available for a particular code, thesecan be added by using the second (Append) option of the Data Entry menu (19). Select the number
by pressing the <Ins> key (20), go to the end of the List screen and hit <Enter> to specify the number(21) and confirm the selection (22). Press <8> (23) and <D>, and enter the data (24). These data
are in decreasing order and have the same pressure head — in this example — as the existing data.
Upon appending the data, press <Esc> twice to return to the Main Menu from which the UTILITIES58

UNSODA 1.0

module was selected (25). Type <5> to sort tabular data and press <Ins> to again specify the code
number through the List option. Confirm the number for sorting (26), and press <8> (27) and <D>
to sort and average all laboratory retention data from the drying curve. Press <Esc> twice to returnto the Main Menu and press <4> to inspect the data through the Edit option (28); better methods forviewing data will be discussed in section 7.2. Upon reaching the Select Type of Data screen (29),press <2> and then<8> and <D> to view the retention data after sorting and averaging. As can beseen (30), the data are in ascending order for the pressure head and each value of the pressure headoccurs only once; the water contents at each of the pressure heads of 100, 500, and 1000 cm havebeen averaged. Contents of the above (example) code can be eliminated by returning to the Main
Menu, selecting the UTILITIES module, and then pressing the Delete Code option (31). Press <Ins>
to again display a list of codes and hit return when the cursor reaches code number 4970, whichneeds deletion. The program will ask to confirm the deletion (32) and update the data tables
accordingly. Return to the Utilities menu by pressing <Esc> and check whether the code has actually
been deleted using the List Codes option <3>. As can be seen (33), the total number of records is
reduced by one and code number 4970 has disappeared from the list. This completes the firstexample session and the Main Menu can be returned to by pressing <Esc> four times.

(1)Chpt. 7. EXAMPLES

(2)

(3)

(4)

59

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(5)

(6)

(7)

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Chpt. 7. EXAMPLES

(8)

(9)

(10)

61

62
(11)

(12)

(13)

UNSODA 1.0

Chpt. 7. EXAMPLES

(14)

(15)

(16)

63

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(17)

(18)

(19)

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(20)

(21)

(22)

65

66
(23)

(24)

(25)

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(26)

(27)

(28)

67

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(29)

(30)

(31)

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(32)

(33)

69

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UNSODA 1.0

7.2. Query and Report Generation

The report feature can first be investigated by browsing through the contents of UNSODA
without conducting a search. Select QUERY AND REPORT GENERATION of the Main Menu (1) andthen press <2>, All Codes, on the Data to be Searched screen (2). The screen is the default output
device of the Device Settings menu (3). The first screen output appears after the Compile Report
option <4> is chosen (4). Use the arrow keys <9> and <8> to view other screens with information
for a code or move to another code by pressing the <PgDn> or <PgUp> keys. The key options are
displayed at the bottom of the screen. Press <Esc> to return to the Data to be Searched screen.

Next, an example is presented which demonstrates a search for information on C horizons
having a silt loam texture and for which the code must be greater than 2000. Select the Specific
Codes option <1> of the Data to be Searched menu. Move through the Specify Search Fields menu
with the arrow keys, press <Enter> or <5> when a field is reached for which a search value needs
to be typed in, and press <Enter> again to set the field. After all three search fields have been set(5), press <F10> to start the query. Select the second option of the Code: screen (6) to specify therange of code numbers ($2000). Information for matching codes can again be written to the screen
by pressing <4> of the Device Settings menu. Codes are now being displayed that match the search
profile (7). Press <Esc> to initiate another search or to return to the Main Menu.

Finally, to retrieve field-measured water retention data, select the Specific Codes option and
go to Field Wat. Ret. Comment on the Specify Search Fields menu and press return to obtaincomments on the right-hand part of the screen (8). Use the <9> key until the desired comment isdisplayed, and then press <Enter> to select the comment (9). Execute the search and write the output
to the screen by subsequently typing <F10> and <4>. There are two matching codes as can be seen
by moving through the screen output (10). In this case the field water retention data for these codes
is to be written to a disk; press <Esc> and repeat the search by using the Specific Tabular Data
option <3> from the Data to be Searched screen (11). After the methodology comment has been

Chpt. 7. EXAMPLES

71

specified, select the Field 2(h) option <4> of the Select Table to Print from (12) and type, forexample, the file name a:\fret.dat (13). The contents of the file can be inspected by returning to theMain Menu and selecting the Utilities option <4>. From the Utilities menu (14) select <7>, View
Text or Data Files, and press <F7> to change directory/drive (15). After specifying the directory
name (a: ), the files currently in the a-directory are displayed on the right-hand side of the screen(16). Use the <9>, <8>, <PgDn>, and <PgUp> keys to move through the directory, press <F6> after
the desired file is found to enter the file name (17), and view the file in the regular manner (18).
Press <Esc> twice to exit the viewing subroutine and return to the Main Menu.

72
(1)

(2)

(3)

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(4)

(5)

(6)

73

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(7)

(8)

(9)

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(10)

(11)

(12)

75

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(13)

(14)

(15)

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(16)

(17)

(18)

77

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UNSODA 1.0

7.3. Models

In the last example session, the unsaturated hydraulic data with a closed-form parametricmodel will be described. To do so, the type of data and hydraulic model that will be used must be
decided. By fitting the first model of Table 3 to the field retention and conductivity data of code
3090 associated with the drying branch, the hydraulic conductivity, K, is given as a function of thepressure head, h. Select the MODELS option from the Main Menu (1) and then choose the second
option — Execute RETC Optimization (2). Type 3090 on the Code to be Modeled screen (3) —this number could also be selected from the code list. Specify the Drying option for the HydraulicCurve screen (4). Then select the Mualem/van Genuchten Model where m is fitted (5). Based on
initial considerations, i.e., to fit both retention and conductivity data, option <1> is specified fromthe Type of Hydraulic Data screen (6), while also specifying Field 2(h) (7) and Field K(h) (8) data.
The next task is to provide initial estimates for the optimization process. Since this is the first
optimization, retrieved values cannot be used. Hence, the suggested (<S>) or textural averaged
values (9) are used, and R is fixed at 0.5 (10). A somewhat meaningless Summary of Options screen(11) appears. This summary may be useful when alternative models have been implemented in
UNSODA. The name of an output file is to be specified on the Output screen (12). After running
RETC, the output file can be viewed with the same routine as in the UTILITIES module through theView Model Output (13). The output can be inspected with the customary keys (14) to decide
whether additional optimizations are necessary, or if the data is suitable to be stored in UNSODA.
After pressing, <Esc> the Store Model Output screen appears. Finally, the option of storing model
results is bypassed by pressing <n>.

Chpt. 7. EXAMPLES

(1)

(2)

(3)

79

80
(4)

(5)

(6)

UNSODA 1.0

Chpt. 7. EXAMPLES

(7)

(8)

(9)

81

82
(10)

(11)

(12)

UNSODA 1.0

Chpt. 7. EXAMPLES

(13)

(14)

83

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UNSODA 1.0

REFERENCES

Brooks, R. H., and A. T. Corey. 1964. Hydraulic properties of porous media. Hydrology Paper No.
3, Colorado State Univ., Fort Collins, Colorado. 27 pp.
Burdine, N. T. 1953. Relative permeability calculations from pore-size distribution data. Petrol.
Trans., Am. Inst. Min. Eng. 198:71-77.
Carsel, R. F., and R. S. Parrish. 1988. Developing joint probability distributions of soil water
retention characteristics. Water Resour. Res. 24:755-769.
Dane, J. H., D. K. Cassel, J. M. Davidson, W. L. Pollans, and V. L. Quisenberry. 1983. Physicalcharacteristics of soils of the Southern region. Troup and Lakeland series. Southern Coop.
Ser. Bull. 262. Alabama Agric. Exp. Sta., Auburn Univ., AL.
Date, C. J. 1986. An introduction to database systems. 4th Ed., Addison-Wesley, Reading, MA.
Gee, G. W., and J. W. Bauder. 1986. Particle-size Analysis. In A. Klute (ed.) Methods of soil
analysis, part 1, Physical and mineralogical methods. Agronomy Monogr. 9, 2nd Ed.
American Society of Agronomy, Madison, WI.
Klute, A. (ed.). 1986. Methods of soil analysis, part 1, Physical and mineralogical methods.
Agronomy Monogr. 9, 2nd Ed. American Society of Agronomy, Madison, WI.
Klute, A., and C. Dirksen. 1986. Hydraulic conductivity and diffusivity: Laboratory methods. In
A. Klute (ed.) Methods of soil analysis, part 1, Physical and mineralogical methods.
Agronomy Monogr. 9, 2nd Ed. American Society of Agronomy, Madison, WI.
Mualem, Y. 1976a. A catalogue of the hydraulic properties of unsaturated soils. Research Project
Report No. 442, Technion, Israel Institute of Technology, Haifa.
Mualem, Y. 1976b. A new model for predicting the hydraulic conductivity of unsaturated porous
media. Water Resour. Res. 12:513-522.
Mualem, Y. 1986. Hydraulic conductivity of unsaturated soils: Prediction and formulas. In A.
Klute (ed.) Methods of soil analysis, part 1, Physical and mineralogical methods. Agronomy
Monogr. 9, 2nd Ed. American Society of Agronomy, Madison, WI.

85

86

UNSODA 1.0

Page, A. L., R. H. Miller, and D. R. Keeney (eds.). 1982. Methods of soil analysis, part 2, Chemical
and microbiological properties. Agronomy Monogr. 9, 2nd Ed. American Society ofAgronomy, Madison, WI.
Soil Survey Staff. 1990. Key to soil taxonomy, fourth edition. SMSS technical monograph no. 6.
Blacksburg, Virginia Tech.
van Genuchten, M. Th. 1980. A closed-form equation for predicting the hydraulic conductivity ofunsaturated soils. Soil Sci. Soc. Am. J. 44:892-898.
van Genuchten, M. Th., F. J. Leij, and L. J. Lund. 1992. Proceedings International Workshop
Indirect methods for estimating the hydraulic properties of unsaturated soils. Univ.
California, Riverside.
van Genuchten, M. Th., F. J. Leij, and S. R. Yates. 1991. The RETC code for quantifying thehydraulic functions of unsaturated soils. EPA/600/2-91/065, U.S. Environmental Protection
Agency, Ada, OK.
Vereecken, H., J. Maes, J. Feyen, and P. Darius. 1989. Estimating the soil moisture retention fromcharacteristic texture, bulk density, and carbon content. Soil Sci. 148:389-403.
Vereecken, H., J. Maes, and J. Feyen. 1990. Estimating unsaturated hydraulic conductivity fromeasily measured soil properties. Soil Sci. 149:1-12.
Walters, R. F. 1987. Database Principles for Personal Computers. Prentice-Hall, Englewood Cliffs,
NJ.
Wösten, J. H. M., M. H. Bannink, and J. Beuving. 1987. Water retention and hydraulicconductivity characteristics of top- and sub-soils in the Netherlands; The Staring series.
Report 1932, Soil Survey Institute, Wageningen, The Netherlands.
Wösten, J. H. M. and J. Bouma. 1992. Applicability of soil survey data to estimate hydraulicproperties of unsaturated soils. p. 463-472. In M. Th. van Genuchten, F. J. Leij, and L. J.
Lund (ed.) Proc. Int. Workshop on Indirect Methods for Estimating the Hydraulic Properties
of Unsaturated Soils. Univ. California, Riverside, CA.

APPENDIX A. Questionnaire for Data
1. Descriptor Data
Family : ________________________________________________
Series : ________________________
Texture : ________________________ ( ________________ )Structure : _____________________________________________
Depth range : ________ cm
Horizon : ________
Depth to ground water : ________ cm
Location : ________________________________________________________________________________________________
Site : __________________________________
Annual rainfall (cm) : _________________________
Average temperature January (o C) : _________________________
Average temperature July (o C) : _________________________
Date : _________________________
Publication : __________________________________________________________________________________________
Contact : ____________________________________________________________________________________________________phone___________________
fax ___________________
Rating : __/10 ( ____________ )Comments

87

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UNSODA 1.0

2. Methodology

Retention

Field : ___________________________________
Lab : ___________________________________

Conductivity

Field : ___________________________________
Lab : ___________________________________

Ksat

Field : ___________________________________
Lab : ___________________________________

Comments

Laboratory

Field

App. A. Questionnaire89

3. Soil properties
Bulk Density (g/cm3):_______

Particle Density (g/cm3):_______

Porosity (cm3/cm3):_______

Organic Matter Content (%):_______

Saturated Conductivity (cm/d):_______

Saturated Water Content (cm3/cm3):_______

pH:_______

CEC (meq/100 g):_______

Electrolyte Level (meq/l):_______SAR (mmol1/2/l1/2):_______ESP (%):_______EC (dS/m):_______

Free Fe and Al Oxide (%):_______

Particle-size
Distribution
Size
(µm)

Comments

Cum. Fraction(g/g)

Mineralogy

MineralMass fraction(%)

Dry Aggregate-SizeDistribution
Size
(mm)

Cum. Fraction
(g/g)

90

UNSODA 1.0

4. Unsaturated Hydraulic Properties

A. Water Retention (_________________________________)
Laboratoryh (cm)Field

2 (cm3/cm3)h (cm)

2 (cm3/cm3)

B. Hydraulic Conductivity (_________________________________)
Laboratoryh (cm)

2 (cm3/cm3)

Field
K (cm/d)h (cm)

2 (cm3/cm3)

K (cm/d)C. Soil Water Diffusivity (_________________________________)
Laboratoryh (cm)

2 (cm3/cm3)

Field
D (cm2/d)h (cm)

2 (cm3/cm3)

D (cm2/d)

APPENDIX B. Sample of Form for Code with Database Information

SAMPLE

1. Descriptor Data
CodeFamilySeriesTextureStructure
Depth Range
HorizonDepth to Ground water
Location
Site
Annual Rainfall (cm)Average Temperature January (oC)Average Temperature July (oC)
Date
Publication

:
:
:
:
:
:
:
:
:
:
:
:
:
:
:

1010
Loamy, siliceous, thermic Grossarenic Paleudults
Trouploamy sandweak granular0-24 cm
Ap
Union Springs, Ala, USA
West plot

1979Southern Cooperative Series Bulletin 262, 1983, Alabama
Agricultural Experiment Station, Auburn University, Alabama
Contact : Dr. J. H. Dane, Dept. of Agronomy and Soils, Auburn University, AL
36849-5412. tel. 205-844-3974; fax 205-844-3945.
Rating :Comments
The site was a pecan orchard with grass cover

2. Methodology
Water Retention

Hydraulic Conductivity
Sat. Hydr. Cond. (Ksat)
Comments
Laboratory

Field

Field
Lab
Field
Lab
Field
Lab

:
:
:
:
:
:

Tensiometry and neutron thermalization
Tempe cell, pressure membrane
Instantaneous profile
Constant head

Undisturbed samples were obtained with a drop hammer type sampler. Sample size: I.D.=5.35 cm andheight=3 cm for retention and 6 cm for saturated conductivity. Water retention was obtained with
Tempe pressure cells, pressure cookers, and pressure membranes. Water outflow volumes between
successive pressures were determined gravimetrically. The saturated hydraulic conductivity wasdetermined with the constant head method using vertical samples.
Average temperature during experiment was 25 oC. Drying curve.
2 by 2 m square plots were bounded by 28-cm high boards placed 12 cm above and 16 cm below thesurface. A neutron probe access tube was installed at the center of each plot to determine watercontents. Soil water pressure head values were obtained using three parallel jet-fill
tensiometers, with cups installed at the same depth for which undisturbed samples were taken. The
hydraulic conductivity was derived by solving the Richards equation using measured head and watercontent profiles during drainage after flood irrigation with a zero flux condition at the surface.
The data are for the first drainage cycle.

91

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UNSODA 1.0

3. Soil properties
Bulk Density (g/cm3)
Particle Density (g/cm3)
Porosity (cm3/cm3)
Organic Matter Content (%)
Saturated Conductivity (cm/d)
Saturated Water Content (cm3/cm3)
CEC (meq/100 g)
pHElectrolyte Level (meq/l)
SAR (mmol1/2/l1/2)
ESP (%)EC (dS/m)Free Fe and Al Oxide (%)

:
1.640
:
2.64
:
0.394
:
0.01
: 171.1
:
0.384
:
:
:
:
:
:
:
-

Particle-Size Distribution
Size
Cum. Fraction
(µm)
(g/g)
<2
0.030
<50
0.170
<106
0.279
<250
0.735
<500
0.921
<1000
0.994
<2000
1.002

Mineralogy
Mineral Mass fraction(%)

Dry Aggregate-Size Distribution
Size
Cum. Fraction
(µm)
(g/g)

Comments
Undisturbed samples for bulk density. Disturbed samples for particle density and soil textural analysis.
Vertical saturated conductivity. The particle-size distribution was determined with dry sieving while the particle
density was determined with the pycnometer method.

App. B. Sample Form

93

4. Unsaturated Hydraulic Properties
A. Water Retention (main drying)
Laboratoryh (cm)
2 (cm3/cm3)h (cm)
0
0.380
13
10
0.348
23
20
0.328
31
30
0.319
37
50
0.212
41
100
0.138
44
200
0.110
51
500
0.087
53
1000
0.069
56
71
86
89
91
92
96
103
109

B. Hydraulic Conductivity (main drying)Fieldh (cm)
2 (cm3/cm3) K (cm/d)
18
27
34
39
42
47
51
79
88
90
110

0.282
0.265
0.251
0.240
0.231
0.215
0.197
0.145
0.134
0.132
0.110

45.6
36.96
30.0
24.24
19.75
11.18
3.05
0.432
0.089
0.022
0.002

Field

2 (cm3/cm3)
0.292
0.273
0.257
0.245
0.235
0.227
0.193
0.181
0.176
0.153
0.136
0.132
0.131
0.128
0.123
0.115
0.110

APPENDIX C. Model Dependent Parts of RETC4.FOR
C*****DATA BI(8)/' WCR '/,BI(9)/' WCS '/,BI(10)/'ALPHA'/,BI(11)/' N '/DATA BI(12)/' M '/,BI(13)/'EXPO '/,BI(14)/'CONDS'/
C*****C
The names for the elements of the vector b={2r,2s,",n,m,R,Ks} are contained in the array BI. They can be
declared in the main program. Note that the choice of parameter names will not affect the optimization
procedure as they are only used for identification in the output; they can be modified for convenience. Thereis no reason to change the names for the six default models from RETC (i.e., MTYPE#6 in UNSODA) but
changes for other models may help interpreting the program output. The names correspond to the parametervalues contained in the array B; obviously, it is important that consistent use is made of the array subscripts
when programming additional hydraulic functions.
CC-----------------------------------------------------------------SUBROUTINE MODEL(B,Y,X,NWC,NOB,MTYPE,METHOD,INDEX,IOR)C
The subroutine MODEL contains the formulations of the default hydraulic functions from RETC. Use thissubroutine also for implementing additional hydraulic models.
C
CC

DEFINE ALTERNATIVE NAMES FOR VARIABLES

IF(MTYPE.GT.6) THENC
C*****
WCR=B(8)WCS=B(9)
ALPHA=B(10)A1=B(11)
A2=B(12)
EXPO=B(13)CONDS=B(14)C*****C
The array elements of the optimization vector can be renamed to help programming additional hydraulicmodels (MTYPE>6). Above is an example of this renaming, the names do not appear in the output and are
only for internal use in the subroutine MODEL.
CCCSpecify additional retention models
SELECT CASE(MTYPE)
CASE(7)C
C*****

94

App. C. RETC4.FOR

95

Y(I)=WCS*(ALPHA*X(I))**(-A1)
C*****C
CASE(8)C
C*****
Y(I)=WCS*(1+(ALPHA*X(I))**A1)**(-A2)
C*****C
C CASE(9)C:C:
END SELECT
Above is an example of the implementation of two additional retention functions, 2(h). Expressions for theretention function, i.e., the water content Y as a function of the pressure head X, need to be programmed by
the user in RETC4.FOR using the CASE statement. Only one function can be used during each run. The
function to be fitted to the data is specified through the variable MTYPE in the MODEL section of UNSODA.
C
C
C
C
C
C

Specify additional conductivity/diffusivity models
METHOD = 2 : CONDUCTIVITY BASED ON WATER CONTENTMETHOD = 4 : CONDUCTIVITY BASED ON HEAD
METHOD = 6 : DIFFUSIVITY BASED ON WATER CONTENTSELECT CASE(MTYPE)
CASE(7)
IF(METHOD.EQ.2) THENC
C*****
DLGC=0C*****CELSE IF (METHOD.EQ.4) THENC
C*****
DLGC=DLOG10(CONDS/(1+ALPHA*X(I))**EXPO)
C*****CELSE IF (METHOD.EQ.6) THENC
C*****
DLGD=0C*****C
ENDIF
CASE(8)

96

UNSODA 1.0

IF(METHOD.EQ.2) THENC
C*****
DLGC=0C*****CELSE IF (METHOD.EQ.4) THENC
C*****
DLGC=DLOG10(CONDS*DEXP(-EXPO*X(I)))
C*****CELSE IF (METHOD.EQ.6) THENC
C*****
DLGD=0C*****
C
ENDIF
C
:
C
:
END SELECT
Expressions for the hydraulic conductivity K(2) and K(h) as well as the soil water diffusivity D(2) can beprovided in a similar manner as for the water retention curve. Note that the optimization takes place on logtransformed conductivity or diffusivity data. Again, only one function can be used during each run. Thisfunction is selected in the MODEL section of UNSODA based on the type of data (METHOD) and theselected model number (MTYPE). The expressions for the 10logK or 10 logD functions also need to be
programmed by the user in RETC4.FOR using the CASE statement. In the above example two functions areprovided for log K(h) (i.e., METHOD=4) for models 7 and 8. If K(2) and D(2) data are to be optimized,
corresponding expressions for log K(2) and log D(2) need to be provided.

APPENDIX D: Menu Structure
Opening screen
Main Menu
1 Data Entry and Edit
Data Entry
1 CREATE
Specify New Code#Descriptor Data 1
Descriptor Data 2
Soil Properties
Add to Database and Continue
Methodology
1 Field 2(h)2 Lab 2(h)3 Field K/D
4 Lab K/D
5 Field Ksat
6 Lab Ksat
7 Field Comment
8 Lab Comment
Tabular Data Type
1 Particle Size Distribution
2 Dry Aggregate Size Distribution
3 Mineralogy
4 Field 2(h)5 Field K(2)6 Field D(2)7 Field K(h)8 Lab 2(h)9 Lab K(2)10 Lab D(2)11 Lab K(h)2 APPEND
Code # for Appending Tabular Data
Tabular Data Type
1 Particle Size Distribution
2 Dry Aggregate Size Distribution
3 Mineralogy
4 Field 2(h)5 Field K(2)6 Field D(2)7 Field K(h)8 Lab 2(h)9 Lab K(2)10 Lab D(2)11 Lab K(h)

97

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UNSODA 1.0
3 DELETE
Code # for Deleting Tabular Data
Tabular Data to be Deleted
1 Particle Size Distribution
2 Mineralogy
3 Dry Aggregate Size Dist.
4 Field 2(h)5 Field K(2)6 Field D(2)7 Field K(h)8 Lab 2(h)9 Lab K(2)10 Lab D(2)11 Lab K(h)4 EDIT
Select Type of Data
1 General Information Data
Enter Code # To Edit
Descriptor Data 1
Descriptor Data 2
Soil Properties
Add to Database and Return to Select Screen
2 Tabular Data
Enter Code # To Edit
Edit Tabular Data
1 Particle Size Distribution
2 Mineralogy
3 Dry Aggregate Size Dist.
4 Field 2(h)5 Field K(2)6 Field D(2)7 Field K(h)8 Lab 2(h)9 Lab K(2)10 Lab D(2)11 Lab K(h)3 Methodology Comments
Enter Code # To Edit
Methodology
1 Field 2(h)2 Lab 2(h)3 Field K/D
4 Lab K/D
5 Field Ksat
6 Lab Ksat
7 Field Comment
8 Lab Comment

App. D. Menu Structure
5 CONVERSION
Conversion Factors for Dimensions
1 Initialize Conversion Factors to 1.0
2 Edit Conversion Factors
6 LIST
2 Query and Report Generation
Codes to be Searched
1 Select Specific Codes
Specify Search Fields(Code: )(Rating: )SearchDevice Settings
1 Screen
2 Disk3 Printer4 Compile(Filename: )2 Select All Codes
Device Settings
1 Screen
2 Disk3 Printer4 Compile(Filename: )3 Write Tabular Data to Disk
Specify Search Fields(Code: )(Rating: )SearchSelect Table to Print From
1 Particle Size Distribution
2 Mineralogy
3 Dry Aggregate Size Distribution
4 Field 2(h)5 Field K(2)6 Field D(2)7 Field K(h)8 Lab 2(h)9 Lab K(2)10 Lab D(2)11 Lab K(h)File Name
4 List of Codes to Screen

99

100
3 Models
1 Add/Delete Model Name
Existing Models
1 Mualem/van Genuchten Model (fitted)
2 Burdine/van Genuchten Model (fitted)
3 Mualem/van Genuchten Model (fixed)
4 Burdine/van Genuchten Model (fixed)
5 Mualem/Brooks and Corey Model
6 Burdine/Brooks and Corey Model
7 etc.
2 Specify RETC parameters
Code to be Modeled
Hydraulic Curve
1 Wetting
2 Drying
Existing Models
Mualem/van Genuchten Model (fitted)
Burdine/van Genuchten Model (fitted)
Mualem/van Genuchten Model (fixed)
Burdine/van Genuchten Model (fixed)
Mualem/Brooks and Corey Model
Burdine/Brooks and Corey Model
etc.
Type of Hydraulic Data
1 Retention and Conductivity/Diffusivity Data
Drying/Wetting Retention
1 Lab 2(h)2 Field 2(h)Drying/Wetting K/D
1 Lab K(h)2 Field K(h)3 Lab K(2)4 Field K(2)5 Lab D(2)6 Field D(2)2 Retention Data Only
Drying/Wetting Retention
1 Lab 2(h)2 Field 2(h)UNSODA 1.0

App. D. Menu Structure

3 Conductivity/Diffusivity Data Only
Drying/Wetting K/D
1 Lab K(h)2 Field K(h)3 Lab K(2)4 Field K(2)5 Lab D(2)6 Field D(2)Initial Parameters for RETC
Fix parameters
Summary of Options
OutputView Model Output
Store Model Output
3 View RETC (model) results
4 Utilities
1 Delete Code1 List Codes and Series Names
2 Delete Record and Exit
Code Number to be Deleted
2 Change Code1 List Codes and Series Names
2 Change Code and Exit
Old Code Number
New Code Number
3 List Codes
4 Reindex Data Tables
5 Sort Tabular Data
Code Number to be Sorted
1 Particle Size Distribution
2 Mineralogy
3 Dry Aggregate Size Distribution
4 Field 2(h)5 Field K(2)6 Field D(2)7 Field K(h)8 Lab 2(h)9 Lab K(2)10 Lab D(2)11 Lab K(h)6 Check Pointer Table
7 View Text or Data Files

101

APPENDIX E: List of Short Methodology Comments
Field Water Retention
1 Tensiometry and neutron thermalization
2 Tensiometry and neutronprobe
3 Tensiometry and gravimetric sampling
4 No comment
5 NA
6 Infiltration under suction and gravimetry
7 Tensiometry and neutron thermalization/gravimetry
8 Tensiometry and TDR
Laboratory Water Retention
1 Tempe cell
2 Buchner cell and pressure plate
3 Tensiometry and gamma attenuation
4 Haines' apparatus and pressure plate
5 Hanging water column
6 Pressure plate
7 Pressure plate and thermocouple psychrometry
8 Pressure outflow
9 Tensiometry and volumetry
10 Tensiometry and TDR
11 Tempe cell and pressure plate
12 Tensiometry and gravimetry
13 Tensiometry and neutron thermalization
14 Tensiometry, pressure plate, and gamma attenuation
15 Vacuum suction
16 Temple cell, pressure membrane
17 No Comment
18 NA
19 Hanging water column and pressure outflow
20 Infiltration under suction and gravimetry
21 Tensiometry/Buchner funnel and pressure outflow
22 Pressure outflow and gravimetry
23 Pressure outflow, gravimetry, and salt solutions
24 Tensiometry and neutron thermalization/TDR
25 Pressure outflow and air drying
Field Hydraulic Conductivity
1 Disc permeameter
2 Guelph permeameter
3 Instantaneous profile
4 Drainage
5 No Comment
6 NA
7 Vacuum on tensiometer102

App. E. Methodology Comments
Laboratory Hydraulic Conductivity
1 Double plate
2 Soil water diffusivity
3 Evaporation
4 Hot air method
5 Instantaneous profile
6 Bruce & Klute
7 Short column
8 Long column
9 Sorptivity
10 Short column, falling head11 Short column, multistep
12 Centrifugation
13 Inverse method
14 No Comment
15 NA
16 Steady state
17 Outflow-inflow (Bruce & Klute)
18 Sprinkling infiltrometer
19 Crust method
20 Crust and hot air methods
Field saturated conductivity
1 Constant head
2 Instantaneous profile
3 Ring infiltrometer
4 Double ring infiltrometer
5 Steady infiltration
6 No comment
7 NA
8 Ponding
9 Falling head permeameter
Laboratory saturated conductivity
1 Constant head
2 Inverse method
3 Falling head
4 Steady infiltration
5 Falling head, short column
6 Steady flow
7 None8 NA103