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dc.contributor.supervisor Rasmussen, Peter (Civil Engineering) Doering, Jay (Civil Engineering) en
dc.contributor.author Halket, Ian
dc.date.accessioned 2010-07-26T16:18:49Z
dc.date.available 2010-07-26T16:18:49Z
dc.date.issued 2010-07-26T16:18:49Z
dc.identifier.uri http://hdl.handle.net/1993/4044
dc.description.abstract One-dimensional steady flow pollutant transport models assume that the river reach modelled has a uniform cross-sectional shape which manifests as a constant average velocity in the model equations. Rarely do rivers meet this criterion. Their channels are seldom uniform in shape, but rather alternate in a quasi-periodic manner between pool and riffle sections. This bedform sequencing imparts a corresponding variation in the average cross-sectional velocity which is not accounted for in constant velocity transport models. The literature points out that the pool and riffle planform may be the reason for the sometimes poor predictions obtained from these models. This thesis confirms that the fluctuation in average cross-sectional velocity caused by the pool and riffle planform does have a marked effect on transport in rivers. The pool and riffle planform promotes an enhanced decay of a pollutant when a first order biochemical reaction is simulated. This effect becomes more pronounced as flow declines. The reason for this is that travel time in a pool and riffle channel is greater than for a uniformly shaped channel. Current one-dimensional models assume a uniform channel and therefore overestimate the velocity of a substance moving downstream. To show this an equation is developed that describes the variation in average cross-sectional velocity along a pool and riffle channel. The parameters of the equation can be easily evaluated for any river. The equation is incorporated into a mass balance analysis and a new form of the river transport model is derived. Analysis shows that the transport of a substance in a pool and riffle channel is governed by travel velocity which is different from the average cross-sectional velocity used in the traditional advection model. Replacing average velocity with travel velocity provides a simple fix for the traditional model. The new transport model is tested on the Athabasca River with excellent results. The variable velocity model successfully simulates the DO dynamics on a 550 kilometre stretch of the river. This suggests that the model has good potential for simulating pollutant transport in other rivers. Since analysis shows that the effect of the pool and riffle planform on contaminant transport is magnified at low flow levels, the model has good potential for use in determining TMDLs for contaminants, because these regulatory levels are set for low flow conditions. en
dc.format.extent 2781508 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US
dc.rights info:eu-repo/semantics/openAccess
dc.subject Water en
dc.subject Quality en
dc.subject Modelling en
dc.title The effect of the pool and riffle on transport in rivers en
dc.type info:eu-repo/semantics/doctoralThesis
dc.degree.discipline Civil Engineering en
dc.contributor.examiningcommittee Cicek, Nazim (Biosystems Engineering) Lobb, David (Soil Science) Steffler, Peter (Water Resources Engineering, University of Alberta) en
dc.degree.level Doctor of Philosophy (Ph.D.) en
dc.description.note October 2010 en


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