SWB Version 2.0—A Soil-Water-Balance Code for Estimating Net Infiltration and Other Water

130 Pages·2017·9.73 MB·English

Water Availability and Use Science Program
National Water Quality Program

SWB Version 2.0—A Soil-Water-Balance Code for Estimating
Net Infiltration and Other Water-Budget Components
Chapter 59 of
Section A, Groundwater
Book 6, Modeling Techniques
Techniques and Methods 6–A59
U.S. Department of the Interior
U.S. Geological Survey
Cover: Image of Soil-Water-Balance (SWB) soil-moisture storage grid for the Maui,
Hawaii, study area.
SWB Version 2.0—A Soil-Water-Balance
Code for Estimating Net Infiltration and Other
Water-Budget Components
By Stephen M. Westenbroek, John A. Engott, Victor A. Kelson, and Randall J. Hunt
Chapter 59 of
Section A, Groundwater
Book 6, Modeling Techniques
Water Availability and Use Science Program
National Water Quality Program
Techniques and Methods 6–A59
U.S. Department of the Interior
U.S. Geological Survey
U.S. Department of the Interior
RYAN K. ZINKE, Secretary
U.S. Geological Survey
James F. Reilly II, Director
U.S. Geological Survey, Reston, Virginia: 2018
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Suggested citation:
Westenbroek, S.M., Engott, J.A., Kelson, V.A., and Hunt, R.J., 2018, SWB Version 2.0—A Soil-Water-Balance code
for estimating net infiltration and other water-budget components: U.S. Geological Survey Techniques and Methods,
book 6, chap. A59, 118 p., https://doi.org/10.3133/tm6A59.
ISSN 2328-7055 (online)
iii
Preface
The Soil-Water-Balance (SWB) version 2.0 code can be downloaded from the U.S. Geological
Survey for free. The performance of SWB version 2.0 has been tested in a variety of
applications. Future applications, however, might reveal errors that were not detected in the
test simulations. Users are requested to send notification of any errors found in this model
documentation report or in the model program to the contact listed on the web page (https://doi.
org/10.5066/tm6A59).
v
Contents
Preface ...........................................................................................................................................................iii
Abstract ...........................................................................................................................................................1
Introduction.....................................................................................................................................................1
Background and Terminology .............................................................................................................2
Scope and Purpose ..............................................................................................................................2
Changes from Previous Versions .......................................................................................................3
Overview of Data and Input Requirements ......................................................................................3
Units of Measurement..........................................................................................................................3
Model Description .........................................................................................................................................5
Processes and Methods ...............................................................................................................................6
Precipitation and Air Temperature .....................................................................................................6
Interception............................................................................................................................................7
Snowfall ..................................................................................................................................................7
Snowmelt................................................................................................................................................7
Fog Interception ....................................................................................................................................7
Runoff ....................................................................................................................................................7
Impervious Surface Runoff .................................................................................................................7
Runoff Routing .......................................................................................................................................7
Potential/Reference Evapotranspiration ..........................................................................................8
Soil-Moisture Retention/Actual Evapotranspiration .......................................................................8
Growing Degree Day ............................................................................................................................8
Crop Coefficients...................................................................................................................................9
Rooting Depth ........................................................................................................................................9
Irrigation Demand and Application ....................................................................................................9
Rejected Net Infiltration ......................................................................................................................9
Summary........................................................................................................................................................10
Acknowledgments .......................................................................................................................................10
References Cited..........................................................................................................................................10
Appendix 1. Method Documentation .......................................................................................................16
Precipitation..................................................................................................................................................16
Interception...................................................................................................................................................17
Bucket ...................................................................................................................................................17
Gash ......................................................................................................................................................17
Horton ...................................................................................................................................................18
Snowfall ................................................................................................................................................18
Snowmelt..............................................................................................................................................18
Fog Interception ..................................................................................................................................19
Runoff .............................................................................................................................................................19
Curve Number......................................................................................................................................20
Published Curve Numbers ........................................................................................................20
Antecedent Runoff Conditions .................................................................................................24
Continuous Frozen Ground Index (CFGI) ................................................................................24
Monthly Runoff Fraction Grid ............................................................................................................25
vi
Impervious Surface Runoff ........................................................................................................................25
Runoff Routing ..............................................................................................................................................26
Potential/Reference Evapotranspiration .................................................................................................27
Jensen-Haise Method........................................................................................................................28
Hargreaves-Samani Method ............................................................................................................28
Monthly Grid ........................................................................................................................................28
Actual Evapotranspiration/Soil-Moisture Retention ..............................................................................29
Thornthwaite-Mather Method ..........................................................................................................30
FAO–56 Method ...................................................................................................................................31
Growing Degree Day ...................................................................................................................................32
Growing Season ...........................................................................................................................................32
Crop Coefficients..........................................................................................................................................33
Rooting Depth ...............................................................................................................................................35
Irrigation Demand and Application ...........................................................................................................35
Rejected Net Infiltration .............................................................................................................................36
References Cited..........................................................................................................................................38
Appendix 2. User Guide .............................................................................................................................40
Installing and Running Soil-Water-Balance Version 2.0 .......................................................................40
System Requirements ........................................................................................................................40
Running SWB.......................................................................................................................................41
Overview of Input and Output Files ...........................................................................................................41
Input Files .............................................................................................................................................41
Control File ..................................................................................................................................41
Lookup Tables .............................................................................................................................45
Input Data Grids .........................................................................................................................45
Hydrologic Soil Group ......................................................................................................46
Available Water Capacity ................................................................................................46
Land-Use Code ..................................................................................................................46
D8 Surface-Water-Flow Direction..................................................................................47
Climate Data Tables or Grids ....................................................................................................47
Output Files ..........................................................................................................................................48
netCDF Files ................................................................................................................................48
Log Files .......................................................................................................................................48
Cartographic Projections and Resampling ..............................................................................................51
Gridded Datasets .........................................................................................................................................53
Specifying Grid Filenames .................................................................................................................54
Options for Gridded Datasets ...........................................................................................................55
Supported File Types ..........................................................................................................................55
Surfer Ascii Grid .........................................................................................................................56
Arc Ascii Grid..............................................................................................................................56
netCDF..........................................................................................................................................57
Treatment of Missing Values.............................................................................................................59
Conversion Factors .............................................................................................................................60
Inactive Grid Cells ...............................................................................................................................61
References Cited..........................................................................................................................................61
vii
Appendix 3. Input Data, Lookup-Table Entries, and Control-File Directives by Method .................62
Precipitation..................................................................................................................................................62
Interception...................................................................................................................................................65
Snowfall .........................................................................................................................................................66
Snowmelt.......................................................................................................................................................66
Fog Interception ...........................................................................................................................................67
Runoff .............................................................................................................................................................68
Impervious Surface Runoff ........................................................................................................................69
Runoff Routing ..............................................................................................................................................70
Potential Evapotranspiration .....................................................................................................................71
Available Water Capacity/Available Water Content ..............................................................................72
Rooting Depth ...............................................................................................................................................73
Soil-Storage Maximum ...............................................................................................................................73
Actual Evapotranspiration/Soil Moisture Retention ..............................................................................75
Crop Coefficients..........................................................................................................................................76
Direct Additions............................................................................................................................................77
Growing Degree Day ...................................................................................................................................80
Growing Season ...........................................................................................................................................81
Irrigation Demand and Application ...........................................................................................................81
Rejected Net Infiltration .............................................................................................................................83
References Cited..........................................................................................................................................83
Appendix 4. Example Applications ..........................................................................................................84
Maui, Hawaii .................................................................................................................................................84
Study Area............................................................................................................................................84
Input Grids and Tables .......................................................................................................................84
Control File ...........................................................................................................................................97
Model Application.............................................................................................................................101
Central Sands, Wisconsin ........................................................................................................................103
Study Area..........................................................................................................................................103
Input Grids and Tables .....................................................................................................................103
Control File .........................................................................................................................................109
Model Application.............................................................................................................................113
References Cited........................................................................................................................................117
Figures
1. Conceptual diagram of Soil-Water-Balance storage reservoirs and processes ..............5
Tables
1. Summary of new process methods available in Soil-Water-Balance (SWB) code
version 2.0. ....................................................................................................................................4
2. List of minimum required data and input files for a typical Soil-Water-Balance
(SWB) run .......................................................................................................................................4
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Conversion Factors
U.S. customary units to International System of Units
Multiply By To obtain
Length
inch (in.) 2.54 centimeter (cm)
inch (in.) 25.4 millimeter (mm)
foot (ft) 0.3048 meter (m)
mile (mi) 1.609 kilometer (km)
Area
square mile (mi2) 2.590 square kilometer (km2)
Density of heat
langley (Ly) 0.0171 equivalent water evaporated in
millimeters (mm)
Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows:
°C = (°F – 32) / 1.8.
Temperature in Fahrenheit (°F) may be converted to Kelvin (K) as follows:
K = (°F - 32) / 1.8 + 273.15.
Temperature in Kelvin (K) may be converted to degrees Fahrenheit (°F) as follows:
°F = (K - 273.15) × 1.8 + 32.
International System of Units to U.S. customary units
Multiply By To obtain
Length
centimeter (cm) 0.3937 inch (in.)
millimeter (mm) 0.03937 inch (in.)
meter (m) 3.2808 foot (ft)
kilometer (km) 0.6215 mile (mi)
Area
square kilometer (km2) 0.3862 square mile (mi2)
Density of heat
langley(Ly) 0.673 equivalent water evaporated in
inches (in.)
Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:
°F = (1.8 × °C) + 32.
Temperature in Celsius (°C) may be converted to Kelvin (K) as follows:
K = °C + 273.15.
Temperature in Kelvin (K) may be converted to degrees Celsius (°C) as follows:
°C = K - 273.15.