Scour from the interstitial spaces in cobble-bed rivers

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dc.contributor.authorJonker V.
dc.contributor.authorRooseboom A.
dc.date.accessioned2011-05-15T15:58:09Z
dc.date.available2011-05-15T15:58:09Z
dc.date.issued2008
dc.description.abstractThe periodic removal of sand from the interstitial spaces between cobbles is extremely important for ecosystem functioning in cobble-bed rivers. In order to flush fine sediments from the interstitial spaces between cobbles in river reaches downstream of dams, specific dam releases known as flushing flows or sediment maintenance flows are utilised. This paper describes the development and calibration of a mathematical model to predict the equilibrium depth of scour of fine sands from between cobbles in terms of applied stream power principles. The model was developed with the aid of physical model experiments and is founded on a stream power model which defines the condition of dynamic equilibrium in a deformed sand-bed river. Calibration was done in the laboratory under clear water conditions and with uniform cobble sizes. The scouring of fine sands in cobble-bed rivers is associated with an increase in absolute bed roughness and an associated decrease in the unit stream power applied along the bed as the cobbles become exposed. When scour ceases, the sand particles on the bed are at the movement threshold and critical conditions exist. In order to establish the relationship between equilibrium scour depth and bed particle characteristics, the power which is required to suspend sand particles under laminar boundary conditions is equated with the turbulent power being applied along the bed.
dc.description.versionArticle
dc.identifier.citationWater SA
dc.identifier.citation34
dc.identifier.citation3
dc.identifier.issn3784738
dc.identifier.urihttp://hdl.handle.net/10019.1/10807
dc.subjectBoundary conditions
dc.subjectBoundary value problems
dc.subjectCalibration
dc.subjectDams
dc.subjectErosion
dc.subjectHydraulic structures
dc.subjectLaw enforcement
dc.subjectLeakage (fluid)
dc.subjectMathematical models
dc.subjectSand
dc.subjectSedimentation
dc.subjectSedimentology
dc.subjectSediments
dc.subjectBed roughness
dc.subjectBoundary conditioning
dc.subjectClear water
dc.subjectCobble-bed
dc.subjectCritical conditions
dc.subjectDynamic equilibrium
dc.subjectEnvironmental flow requirements
dc.subjectFine sediments
dc.subjectFlushing flows
dc.subjectInterstitial spaces
dc.subjectMovement threshold
dc.subjectParticle characteristics
dc.subjectPhysical model
dc.subjectSand particles
dc.subjectSand-bed river
dc.subjectScour depth
dc.subjectStream power
dc.subjectStream power model
dc.subjectUnit stream power
dc.subjectRivers
dc.subjectbed roughness
dc.subjectboundary condition
dc.subjectcalibration
dc.subjectecosystem function
dc.subjectflushing
dc.subjectinterstitial environment
dc.subjectlaboratory method
dc.subjectnumerical model
dc.subjectsand
dc.subjectscour
dc.subjectstream
dc.titleScour from the interstitial spaces in cobble-bed rivers
dc.typeArticle
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