Wood-mediated geomorphic effects of a jökulhlaup in the Wind River Mountains, Wyoming
| dc.contributor.author | Oswald, Elizabeth B., author | |
| dc.contributor.author | Wohl, Ellen, advisor | |
| dc.contributor.author | Nelson, Peter, committee member | |
| dc.contributor.author | Rathburn, Sara, committee member | |
| dc.date.accessioned | 2016-01-11T15:14:05Z | |
| dc.date.available | 2016-01-11T15:14:05Z | |
| dc.date.issued | 2015 | |
| dc.description.abstract | A jökulhlaup burst from the head of Grasshopper Glacier in Wyoming's Wind River Mountains during early September 2003. Five reaches with distinct sedimentation patterns were delineated along the Dinwoody Creek drainage. This thesis focuses on a portion of the jökulhlaup route where erosion of the forested banks created sixteen large logjams spaced at longitudinal intervals of tens to hundreds of meters. Aggradation within the main channel upstream from each logjam created local sediment wedges, and the jams facilitated overbank deposition during the jökulhlaup. Field surveys during 2004 and 2006 documented logjam characteristics and associated erosional and depositional features, as well as initial modification of the logjams and flood deposits within the normal seasonal high-flow channel. Overbank deposits have not been altered by flows occurring since 2003. Field measurements supported three hypotheses: (i) Logjams present along the forested portions of the jökulhlaup route are larger and more closely spaced than those along adjacent, otherwise comparable stream channels that have not recently experienced a jökulhlaup; (ii) logjams are not randomly located along the jökulhlaup route, but instead reflect specific conditions of channel and valley geometry and flood hydraulics; and (iii) the presence of logjams facilitated significant erosional and depositional effects. This thesis documents a sequence of events in which outburst floodwaters enhance bank erosion and recruitment of wood into the channel and thus the formation of large logjams. These logjams sufficiently deflect flow to create substantial overbank deposition in areas of the valley bottom not commonly accessed by normal snowmelt peak discharges and through this process promote valley-bottom aggradation and sediment storage. Changes in the occurrence of glacier outburst floods thus have the potential to alter the rate and magnitude of valley-bottom dynamics in these environments, which is particularly relevant given predictions of worldwide global warming and glacial retreat. Processes observed at this field site likely occur in other forested catchments with headwater glaciers. | |
| dc.format.medium | born digital | |
| dc.format.medium | masters theses | |
| dc.identifier | Oswald_colostate_0053N_13397.pdf | |
| dc.identifier.uri | http://hdl.handle.net/10217/170420 | |
| dc.language | English | |
| dc.language.iso | eng | |
| dc.publisher | Colorado State University. Libraries | |
| dc.relation.ispartof | 2000-2019 | |
| dc.rights | Copyright 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.title | Wood-mediated geomorphic effects of a jökulhlaup in the Wind River Mountains, Wyoming | |
| dc.type | Text | |
| dcterms.rights.dpla | This 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.discipline | Geosciences | |
| thesis.degree.grantor | Colorado State University | |
| thesis.degree.level | Masters | |
| thesis.degree.name | Master of Science (M.S.) |
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