Author(s): Shalini Kashyap; Benoît Doutreleau; Georges Bou-Botros; Colin D. Rennie; Ronald Townsend

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Keywords: Alluvial channel; bed fixation; bed hardening; morphology; roughness; transitional flow

Abstract: A new flume bed-sediment hardening method employing a surficial layer of plaster of Paris coated by spar urethane has been developed and tested for sand beds. Unlike existing bed-hardening techniques, this method is gentle enough to be used in and subsequently removed from a laboratory flume made of Plexiglas, yet is durable enough to last several days under flowing water. Tests showed that artificially fixed beds withstand an estimated bed shear stress of up to 0.251 N/m2 for 52 h. The effects of the hardening technique on bed roughness were evaluated. A mean absolute difference in the bed roughness estimate between fixed and loose beds of 0.166 mm was found when tested on a sand bed. Although roughness estimates seemed reasonable, standard deviations were high. Further testing under a wider range of flow conditions and sediment sizes is required to assess the effect of the hardening technique on roughness.

DOI: https://doi.org/10.1080/00221686.2010.481831

Year: 2010