Author(s): Hao-Che Ho; Marian Muste; Robert Ettema
Keywords: Culverts; deposition; sedimentation; sediment transport; self-cleaning
Abstract: Field investigations of culvert sites and surveys of road maintenance personnel reveal that sedimentation is a widespread problem for multi-barrel culverts in Iowa and neighbouring US Midwest states. Current maintenance practice entails arduous excavation of sediment deposits by mechanical or hand methods. The present paper describes culvert-approach designs that mitigate sedimentation in culverts. The designs take advantage of the sediment transport capacity of culvert-approach flows, hence the label of self-cleaning designs. The method entails using infill fillets designed to modify the approach-channel geometry in the transition area from stream to the culvert entrance, so as to maintain the flow distribution as close as possible to the original stream configuration. The dimensions of the fillets were established by means of hydraulic and numerical models covering a range of flows and culvert geometry. Performance tests show that the fillets mitigate sedimentation upstream and within the culvert. The paper gives a general guidance on design dimensioning for the fillets, which can be placed at new or existing culverts.