Effects of Sediment‐Laden Flow on Channel Bed Clogging

In open channel systems the phenomenon commonly referred to as clogging is caused by settling and straining of suspended sediment as water moves through the channel bed material, as well as by microbial transport, colonization, and other biological and chemical action. This paper summarizes a three‐year investigation of the clogging process due to accumulation of fine soil particles as it occurs in sediment‐laden open channel flow. Significant results include experimental relationships developed between major independent variables (i.e., flow velocity, suspended sediment concentration, and suspended sediment particle size distribution) and the infiltration reduction occurring through a sand bed filter in the bottom of a recirculating laboratory flume. Factors affecting both magnitude and temporal variation of channel bed infiltration are explained as well as observed differences in the physical nature of the clogged layer developed atop the filter bed. Significant features of sedimentary clogging in open channel flow are also correlated with traditional hydraulic and sediment transport variables and processes. In addition, a dimensional analysis of sedimentary clogging is presented as a focus for future experimental investigation.