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Hazard area mapping during extreme rainstorms in South Korean mountains

dc.contributor.authorKim, Jaehoon, author
dc.contributor.authorJulien, Pierre Y., advisor
dc.contributor.authorWatson, Chester C., committee member
dc.contributor.authorThornton, Christopher I., committee member
dc.contributor.authorMacDonald, Lee H., committee member
dc.date.accessioned2007-01-03T05:58:40Z
dc.date.available2007-01-03T05:58:40Z
dc.date.issued2012
dc.description.abstractThe concern for climate change has increased worldwide. Localized rain storms with high intensity and short duration have been observed in the United States, Europe, Australia, and China. South Korea is one of the countries that have also been impacted by extreme rainfall events during typhoons. Extreme rainstorms have caused major damage from landslides and debris flows in the South Korean mountains. The Duksan Creek watershed in South Korea was selected to simulate surface runoff using TREX during the extreme rainstorm precipitation event from July 14 to July 16, 2006. The maximum hourly rainfall was 62 mm on July 15 in 2006. The three hour rainfall from 08:00 AM to 11:00AM on this day was 168 mm. This rainstorm triggered 518 landslides and caused major infrastructure damage from debris flows. The three hour rainfall precipitation has a 100 year return period. The TREX model was calibrated in two mountainous regions of South Korea. The relative percent difference of time to peak and peak discharge on the Naerin Stream and the Naesung Stream were 6.25 %, -2.58 % and 1.90 %, -0.25 %, respectively. The TREX simulation at the Duksan Creek was performed at a 30 m resolution with distributed data on topography (DEM), soil type, and land use. The peak discharge from the TREX simulation at the Duksan Creek watershed was 452 m3/s. This value was compared to the results of several other methods and the relative percent difference was -1.1 %. The peak discharge was also compared with specific peak discharge measurements and this value corresponds to the range of values for similar watersheds. The TREX model can calculate the distribution of infiltration depth. The infiltration depth calculation typically ranged from 0.2 m to 0.3m with maximum value of 1.2 m. Based on the infinite slope analysis, such infiltration depths correspond to a critical slope angle of 25° to 29°. This range of the critical slope angle was comparable to the angle of 26° from the field investigations and from the analysis of satellite images and aerial photographs at the Duksan Creek. Several different hazard mapping methods were compared including a landslide hazard map from the Korea Forest Institute (KFRI), SINMAP, and TREX. The result of the relative predictability of TREX was slightly better an improvement of 24.6 % than the result of SINMAP. The maximum shear stress could also be calculated by the TREX model. Values of shear stress typically ranged between 0.223 kPa to 0.895 kPa in the tributaries and 1.79 kPa to 17 kPa in the main channel. Based on a critical shear stress analysis, a 1 m diameter boulder reaches incipient motion at a shear stress of 0.895 kPa.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.identifierKim_colostate_0053A_11531_opt.pdf
dc.identifierETDF2012500358CVEE
dc.identifier.urihttp://hdl.handle.net/10217/80350
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.subjectdebris flow
dc.subjectextreme event
dc.subjecthazard area
dc.subjectlandslide
dc.subjectmapping
dc.subjectmountains
dc.titleHazard area mapping during extreme rainstorms in South Korean mountains
dc.typeText
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.levelDoctoral
thesis.degree.nameDoctor of Philosophy (Ph.D.)

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