Abstract

River off-take is one of the complex features influvial systems and the distribution of flow, and sediments alongthe branches are still a matter of research. This paper dealswith a physical simulation on an off-take channel forunderstanding the flow and sediment distribution in the vicinity.Laboratory-based test runs have been carried out by changingthe discharges and the angles off-take. A total of eighteen testruns have been conducted for three discharge conditions withthree off-take angles. Two equations for predicting water andsediment discharge ratios have been proposed as a function ofFroude number, channel geometry and off-take angel. Flowvisualizations have also been carried out in the vicinity of theoff-take for understanding erosion and sedimentation pattern.Flow and sediment movement patterns were carefully observedduring the simulation and four distinguished zone formationshave been noted in the vicinity. Finally, validations of thedeveloped equations have been done with the field data fromselected river off-take systems of Bangladesh. Validation resultsof field data show mean discrepancy ratios of 0.83 for thedischarge equation and 0.89 for sediment equation during lowflow.