Persistent Link:
http://hdl.handle.net/10150/620103
Title:
A RANDOM-WALK SIMULATION MODEL OF ALLUVIAL-FAN DEPOSITION
Author:
Price, Williams Evans, Jr.
Affiliation:
Department of Hydrology & Water Resources, The University of Arizona
Publisher:
Department of Hydrology and Water Resources, University of Arizona (Tucson, AZ)
Issue Date:
1972-06
Rights:
Copyright © Arizona Board of Regents
Collection Information:
This title from the Hydrology & Water Resources Technical Reports collection is made available by the Department of Hydrology & Atmospheric Sciences and the University Libraries, University of Arizona. If you have questions about titles in this collection, please contact repository@u.library.arizona.edu.
Abstract:
A digital model based on a random walk was used in an experiment to determine how well such a model is able to simulate alluvial - fan deposition. The model is in three dimensions and is dynamic with respect to both time and space. Two principal stochastic events were employed, (1) a relative uplift of the mountain area that is the source of the fan sediments, and (2) a storm event of sufficient magnitude to result in the deposition of material on the fan. These two events are assumed to follow independent Poisson processes with exponentially distributed interoccurrence times. The pattern of deposition is determined by a random walk from the canyon mouth at the mountain front, and each depositional event is assumed to occur instantaneously. The direction that each step in the walk takes is determined probabilistically by the gradient in the direction of flow, the momentum of flow, and the boundary conditions stipulated in the model. The type of flow, whether a depositing debris or water flow, or eroding water flow, depends upon the thickness of erodible material in the source basin. Deposition is assumed to occur over the entire route of flow either as a bed tapered in the direction of flow or as a bed of uniform thickness. The particle -size distribution of the water -flow deposits is governed by the slope in the direction of flow. Erosion is considered negative deposition and results from the exponential decline in elevation of the main stream channel at the fan apex during periods of no uplift, or from water flows containing little basin sediment. Results from the computer runs were printed as geologic maps of the fan surface, and geologic sections through the deposits; these indicate that, at least qualitatively, a random -walk model provides a reasonable basis for simulating alluvial -fan deposition.
Keywords:
Alluvial fans -- Mathematical models.
Series/Report no.:
Technical Reports on Hydrology and Water Resources, No. 7
Sponsors:
The work upon which this dissertation is based is part of the Office of Water Resources Research project A-020-Ariz. Funds for the project were provided by the United States Department of the Interior, Office of Water Resources Research, as authorized under the Water Resources Act of 1964.

Full metadata record

DC FieldValue Language
dc.contributor.authorPrice, Williams Evans, Jr.en
dc.date.accessioned2016-09-13T22:23:22Z-
dc.date.available2016-09-13T22:23:22Z-
dc.date.issued1972-06-
dc.identifier.urihttp://hdl.handle.net/10150/620103-
dc.description.abstractA digital model based on a random walk was used in an experiment to determine how well such a model is able to simulate alluvial - fan deposition. The model is in three dimensions and is dynamic with respect to both time and space. Two principal stochastic events were employed, (1) a relative uplift of the mountain area that is the source of the fan sediments, and (2) a storm event of sufficient magnitude to result in the deposition of material on the fan. These two events are assumed to follow independent Poisson processes with exponentially distributed interoccurrence times. The pattern of deposition is determined by a random walk from the canyon mouth at the mountain front, and each depositional event is assumed to occur instantaneously. The direction that each step in the walk takes is determined probabilistically by the gradient in the direction of flow, the momentum of flow, and the boundary conditions stipulated in the model. The type of flow, whether a depositing debris or water flow, or eroding water flow, depends upon the thickness of erodible material in the source basin. Deposition is assumed to occur over the entire route of flow either as a bed tapered in the direction of flow or as a bed of uniform thickness. The particle -size distribution of the water -flow deposits is governed by the slope in the direction of flow. Erosion is considered negative deposition and results from the exponential decline in elevation of the main stream channel at the fan apex during periods of no uplift, or from water flows containing little basin sediment. Results from the computer runs were printed as geologic maps of the fan surface, and geologic sections through the deposits; these indicate that, at least qualitatively, a random -walk model provides a reasonable basis for simulating alluvial -fan deposition.en
dc.description.sponsorshipThe work upon which this dissertation is based is part of the Office of Water Resources Research project A-020-Ariz. Funds for the project were provided by the United States Department of the Interior, Office of Water Resources Research, as authorized under the Water Resources Act of 1964.en
dc.language.isoen_USen
dc.publisherDepartment of Hydrology and Water Resources, University of Arizona (Tucson, AZ)en
dc.relation.ispartofseriesTechnical Reports on Hydrology and Water Resources, No. 7en
dc.rightsCopyright © Arizona Board of Regentsen
dc.sourceProvided by the Department of Hydrology and Water Resources.en
dc.subjectAlluvial fans -- Mathematical models.en
dc.titleA RANDOM-WALK SIMULATION MODEL OF ALLUVIAL-FAN DEPOSITIONen_US
dc.typetexten
dc.typeTechnical Reporten
dc.contributor.departmentDepartment of Hydrology & Water Resources, The University of Arizonaen
dc.description.collectioninformationThis title from the Hydrology & Water Resources Technical Reports collection is made available by the Department of Hydrology & Atmospheric Sciences and the University Libraries, University of Arizona. If you have questions about titles in this collection, please contact repository@u.library.arizona.edu.en
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