Hydrology, hydraulics, and sediment transport of pleistocene Lake Bonneville flooding on the Snake River, Idaho

Persistent Link:
http://hdl.handle.net/10150/191159
Title:
Hydrology, hydraulics, and sediment transport of pleistocene Lake Bonneville flooding on the Snake River, Idaho
Author:
O'Connor, Jim E.
Issue Date:
1990
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Approximately 14,500 years ago, Pleistocene Lake Bonneville discharged 4750 km 3 of water over the divide between the closed Bonneville Basin and the watershed of the Snake River. The resulting flood, emanating from the divide at Red Rock Pass, Idaho, followed the present courses of Marsh Creek, the Portneuf River, and the Snake and Columbia Rivers before reaching the Pacific Ocean. For the 1100 kilometers between Red Rock Pass and Lewiston, Idaho, the Bonneville Flood left a spectacular array of flood features that have allowed for geologic reconstruction and quantitative evaluation of many aspects of the flood hydrology, hydraulics, and sediment transport. Geologic evidence of maximum flood stages in conjunction with step-backwater modeling provides for peak discharge estimates and understanding of local hydraulic flow conditions for ten separate reaches along the flood route. Peak discharge was approximately 1.0 million m³•sec⁻¹ at the Lake Bonneville outlet near Red Rock Pass. Downstream, the maximum discharge had attenuated to 0.57-0.62 million m³•sec⁻¹ by arrival at Lewiston. Attenuation was primarily the result of flow storage in the wide alluvial valleys of the western Snake River Plain. The local hydraulic conditions (depth and velocity) of the Bonneville Flood varied significantly within and between the study reaches. The rate of energy expenditure was also highly varied; local calculated stream-power values ranged from less than 10 watts•m² to 100,000 watts•m². Greater than 60% of the total energy loss at peak discharge was expended in a total distance that encompassed less than 10% of the flood route. These spatial variations in local hydraulic conditions were profoundly important in controlling the distribution of flood processes and features. The deposition of tractively-transported cobbles and boulders (measured diameters ranged from less than 10 cm to greater than 10 m) occurred in reaches of decreasing flow energy within quantitatively-definable limits of flow energy. Areas of erosion are more difficult to precisely evaluate; however, they were restricted to reaches of greater stream power. It is likely that cavitation was an important erosional agent in many areas of most intense flow conditions.
Type:
Dissertation-Reproduction (electronic); text
Keywords:
Hydrology.; Geology -- Bonneville, Lake.; Lakes -- Bonneville, Lake.; Geomorphology -- Bonneville, Lake.
Degree Name:
Ph. D.
Degree Level:
doctoral
Degree Program:
Geosciences; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Baker, Victor R.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleHydrology, hydraulics, and sediment transport of pleistocene Lake Bonneville flooding on the Snake River, Idahoen_US
dc.creatorO'Connor, Jim E.en_US
dc.contributor.authorO'Connor, Jim E.en_US
dc.date.issued1990en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractApproximately 14,500 years ago, Pleistocene Lake Bonneville discharged 4750 km 3 of water over the divide between the closed Bonneville Basin and the watershed of the Snake River. The resulting flood, emanating from the divide at Red Rock Pass, Idaho, followed the present courses of Marsh Creek, the Portneuf River, and the Snake and Columbia Rivers before reaching the Pacific Ocean. For the 1100 kilometers between Red Rock Pass and Lewiston, Idaho, the Bonneville Flood left a spectacular array of flood features that have allowed for geologic reconstruction and quantitative evaluation of many aspects of the flood hydrology, hydraulics, and sediment transport. Geologic evidence of maximum flood stages in conjunction with step-backwater modeling provides for peak discharge estimates and understanding of local hydraulic flow conditions for ten separate reaches along the flood route. Peak discharge was approximately 1.0 million m³•sec⁻¹ at the Lake Bonneville outlet near Red Rock Pass. Downstream, the maximum discharge had attenuated to 0.57-0.62 million m³•sec⁻¹ by arrival at Lewiston. Attenuation was primarily the result of flow storage in the wide alluvial valleys of the western Snake River Plain. The local hydraulic conditions (depth and velocity) of the Bonneville Flood varied significantly within and between the study reaches. The rate of energy expenditure was also highly varied; local calculated stream-power values ranged from less than 10 watts•m² to 100,000 watts•m². Greater than 60% of the total energy loss at peak discharge was expended in a total distance that encompassed less than 10% of the flood route. These spatial variations in local hydraulic conditions were profoundly important in controlling the distribution of flood processes and features. The deposition of tractively-transported cobbles and boulders (measured diameters ranged from less than 10 cm to greater than 10 m) occurred in reaches of decreasing flow energy within quantitatively-definable limits of flow energy. Areas of erosion are more difficult to precisely evaluate; however, they were restricted to reaches of greater stream power. It is likely that cavitation was an important erosional agent in many areas of most intense flow conditions.en_US
dc.description.notehydrology collectionen_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.typetexten_US
dc.subjectHydrology.en_US
dc.subjectGeology -- Bonneville, Lake.en_US
dc.subjectLakes -- Bonneville, Lake.en_US
dc.subjectGeomorphology -- Bonneville, Lake.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGeosciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairBaker, Victor R.en_US
dc.contributor.committeememberClark, Roberten_US
dc.contributor.committeememberDavis, Owen K.en_US
dc.contributor.committeememberBull, William B.en_US
dc.contributor.committeememberInce, Simonen_US
dc.identifier.oclc213299590en_US
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