Bridging process threshold for sediment infiltrating into a coarse substrate

Sand infiltration into gravel frameworks poses significant engineering and ecological difficulties. Ten flume experiments were conducted to quantify a sand bridging threshold in a static gravel bed. The [D.sub.15] substrate/[d.sub.85] sand ratio was computed for each of 37 unique sand-substrate pairs and the data were plotted, with previously published flume data, to determine the threshold between bridging and unimpeded static percolation. The process threshold boundary between bridging and unimpeded static percolation fell in the range of 12 DOI: 10.1061/(ASCE)GT.1943-5606.0000219 CE Database subject headings. Sand, filters; Silts; Constriction; Gravel; Flumes; Experimentation; Bridges; Sediment; Infiltrating; Substrates. Author keywords: Filter; Siltation; Critical constriction; Gravel clogging; Bridging; Flume experiment.