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dc.contributor.advisorSinger, Michael B.
dc.contributor.authorSlater, Louise J.
dc.coverage.spatial245en_US
dc.date.accessioned2015-07-06T14:30:34Z
dc.date.available2015-07-06T14:30:34Z
dc.date.issued2015-06
dc.identifieruk.bl.ethos.655447 
dc.identifier.urihttps://hdl.handle.net/10023/6913
dc.description.abstractAlluvial river channels are self-formed by the sediment-laden flow that is supplied to them from upstream and the interactions between this flow and the materials forming the channel bed and banks. Thus, any changes in the volumes of solid and liquid discharge or the resistance of the boundary materials can produce adjustments in the form of river channels over time. These shifts may increase or decrease the capacity of a channel to contain flood flows. However, despite a wealth of studies on the average geometry of river channels across different scales and climatic regimes, there has not yet been a systematic assessment of the rates and controls of trends in channel form. Using a combination of USGS data, including manual field measurements and mean daily streamflow data at hundreds of stream gages, this work is the first attempt to quantify how trends in channel geometry develop over decadal timescales and how they contribute to shifts in flood hazard, in comparison with trends in streamflow. Findings reveal that two-thirds of all channel cross-sections studied exhibit significant trends in channel geometry. The majority of the investigated US river channels are eroding, with widening and deepening trends partially offset by decreases in average flow velocity. Rates of change are principally controlled by the channel size. Although large channels develop larger trends, changes are proportionally greater in small channels in percentage terms. A secondary major control is hydrology: rates of change in channel geometry are heightened by the variability and flashiness of flow regimes. Finally, results show that changing flood frequencies can only be accurately quantified when both hydrologic and geomorphic trends are accounted for, and that flood hazard is significantly increasing across the studied sites. These documented trends in channel geometry, hydraulics, and flood hazard have important implications for the management of alluvial channels, navigation, and riverside infrastructure.en_US
dc.language.isoenen_US
dc.publisherUniversity of St Andrewsen
dc.rightsCreative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subjectGeomorphologyen_US
dc.subjectHydrologyen_US
dc.subjectStreamflowen_US
dc.subjectFloodsen_US
dc.subjectTrendsen_US
dc.subjectTime-series analysisen_US
dc.subjectChannel geometryen_US
dc.subjectChannel adjustmenten_US
dc.subjectUSGSen_US
dc.subjectHydrometric dataen
dc.subject.lccGB564.S6
dc.subject.lcshRiver channels--United Statesen_US
dc.subject.lcshFluvial geomorphology--United Statesen_US
dc.subject.lcshRiver channelsen_US
dc.subject.lcshFluvial geomorphologyen_US
dc.subject.lcshSedimentation and depositionen_US
dc.titleTrends in alluvial channel geometry and streamflow : an investigation of patterns and controlsen_US
dc.typeThesisen_US
dc.contributor.sponsorNatural Environment Research Council (NERC)en_US
dc.type.qualificationlevelDoctoralen_US
dc.type.qualificationnamePhD Doctor of Philosophyen_US
dc.publisher.institutionThe University of St Andrewsen_US
dc.identifier.doihttps://doi.org/10.17630/10023-6913


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Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Except where otherwise noted within the work, this item's licence for re-use is described as Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International