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Modeling hydrologic processes associated with soil saturation and debris flow initiation during the September 2013 storm, Colorado Front Range

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dc.contributor.authorTimilsina, Sujana, author
dc.contributor.authorNiemann, Jeffrey D., advisor
dc.contributor.authorRathburn, Sara L., committee member
dc.contributor.authorNelson, Peter A., committee member
dc.date.accessioned2019-09-10T14:35:57Z
dc.date.available2020-09-03T14:36:28Z
dc.date.issued2019
dc.description.abstractSeven days of extreme rainfall during September 2013 produced more than 1,100 debris flows in the Colorado Front Range, about 78% of which occurred on south-facing slopes (SFS). A few previously-published soil moisture observations suggest that SFS were wetter than north-facing slopes (NFS) during the event, which would contrast with soil moisture patterns observed during dry conditions. Various causes have been hypothesized for the preferential saturation of SFS, but those hypotheses remain largely untested. The objectives of this study are to analyze the soil moisture patterns using additional soil moisture observations, determine the hydrologic processes behind the preferential saturation of SFS, and to evaluate the importance of soil moisture in determining the debris flow initiation sites. Soil moisture patterns are simulated using the Equilibrium Moisture from Topography, Vegetation, and Soil (EMT+VS) model for a study region that includes 63% of the observed debris flow locations. Five hypotheses are implemented in the model including: (1) higher rainfall rates, (2) lower interception rates, (3) lower porosity, (4) thinner soils, and (5) reduced deep drainage on SFS. The EMT+VS model is also coupled with an infinite slope stability model to produce factor of safety maps. The hypotheses are tested by comparing the modeled soil moisture patterns to soil moisture observations and the debris flow initiation sites. The results suggest that differences in interception and deep drainage between the slopes were primarily responsible for producing wetter SFS, but the soil moisture pattern likely played a smaller role than vegetation and slope in determining the debris initiation sites.
dc.format.mediumborn digital
dc.format.mediummasters theses
dc.identifierTimilsina_colostate_0053N_15572.pdf
dc.identifier.urihttps://hdl.handle.net/10217/197344
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.subjectColorado
dc.subjectsoil saturation
dc.subjectvegetation
dc.subjectdebris flows
dc.subjectaspect
dc.subjectstability
dc.titleModeling hydrologic processes associated with soil saturation and debris flow initiation during the September 2013 storm, Colorado Front Range
dc.typeText
dcterms.embargo.expires2020-09-03
dcterms.embargo.terms2020-09-03
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineCivil and Environmental Engineering
thesis.degree.grantorColorado State University
thesis.degree.levelMasters
thesis.degree.nameMaster of Science (M.S.)

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