Abstract:
TRIGRS (Transient Rainfall Infiltration and Grid-based Regional Slope-Stability Model) is a Fortran program for computing transient pore-pressure changes, and attendant changes in the factor of safety, due to rainfall infiltration using the method outlined by Iverson (2000). We have extended Iverson's (2000) method by implementing the solution for complex storms, a solution for additional basal ... boundary conditions, and a simple runoff-routing scheme. The program operates on a gridded elevation model of a map area and accepts input from a series of ASCII text files. Infiltration, hydraulic properties, and slope stability input parameters are allowed to vary over the grid area thus making it possible to analyze complex storm sequences over geologically complex terrain. The optional routing scheme achieves mass balance between rainfall input, infiltration, and runoff over the entire grid by allowing excess water to flow to downslope cells that are receiving less direct precipitation than they are able to absorb. The program saves output to a series of text files that can be imported to GIS software for display or further analysis.
Analyses using TRIGRS are applicable to areas that are prone to shallow precipitation-induced landslides and that satisfy other model assumptions reasonably well. These assumptions include nearly saturated soil, a well-documented flow field and relatively isotropic, homogeneous hydrologic properties. The saturated soil assumption is approximately satisfied during the winter rainy season in parts of the U.S. Pacific coast region (Baum and others, 2002). Significant hydraulic heterogeneity may cause errors at boundaries between materials of differing hydraulic properties because TRIGRS uses infiltration models for a homogeneous, isotropic medium. However, we have not evaluated the magnitude of such possible errors. Model results are very sensitive to the initial conditions, particularly the steady component of the flow field and initial depth of the water table. Consequently, the model may produce questionable results where the initial water table depth is poorly constrained.
TRIGRS runs in a simple input/output window with relatively little user interaction. The user controls an analysis by means of an initialization file that contains the names of all other input and output files as well as other parameters needed to run the program. The following discussion will briefly describe system requirements for running the program, installation, features and limitations of the program, and provide a detailed description of the initialization file. A tutorial helps familiarize the user with program features and operation.
Originators:
Rex L. Baum, William Z. Savage, and Jonathan W. Godt
Title:
A Fortran Program for Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Analysis
Release_Date:
2002
Provider:
USGS
Edition:
1.0
URL:
http://pubs.usgs.gov/of/2002/ofr-02-424/
Quality
This open-file report was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof nor any of their employees makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report or represents that ... its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
Although all data and software in this open-file report have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and (or) the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data, software, or related materials.
Name:
LYNN
M.
HIGHLAND
Phone:
(800) 654-4966
Fax:
(303) 273-8600
Email:
highland at usgs.gov
Contact Address:
US Geological Survey
National Landslide Hazards Program
National Landslide Information Center
MS 966, Box 25046
Denver Federal Center City:
Denver
Province or State:
CO
Postal Code:
80225
Country:
USA
Distribution Media
Distribution_Media:
Online
Distribution_Size:
PC: (544K) Mac: (676K)
Fees:
No fees
Personnel
TYLER
B.
STEVENS Role:
SERF AUTHOR
Phone:
(301) 614-6898
Fax:
301-614-5268
Email:
Tyler.B.Stevens at nasa.gov
Contact Address:
NASA Goddard Space Flight Center
Global Change Master Directory City:
Greenbelt
Province or State:
MD
Postal Code:
20771
Country:
USA
LYNN
M.
HIGHLAND Role:
TECHNICAL CONTACT
Phone:
(800) 654-4966
Fax:
(303) 273-8600
Email:
highland at usgs.gov
Contact Address:
US Geological Survey
National Landslide Hazards Program
National Landslide Information Center
MS 966, Box 25046
Denver Federal Center City:
Denver
Province or State:
CO
Postal Code:
80225
Country:
USA
Publications/References
ADDITIONAL REFERENCES:
"Chicken and Eggs, Final Estimates, 1988-93," Statistical Bulletin No. 908, released January 18, 1995, National Agricultural Statistics Service, USDA.
Creation and Review Dates
SERF Creation Date:
2008-04-10
SERF Last Revision Date:
2009-02-17
Links
