Two scientists install walling tubes in an agricultural drainage ditch

Walling tubes, passive sediment samplers, are installed in a series of streams, with concentrations in a small, upland basin that includes a mixture of retired-riparian corridor, tile drainage, and agricultural management.  These samplers are situated above the low-flow stream surface so that when stream depth increases during a storm or snowmelt event that is likely to mobilize sediment, the samplers are submerged and collect and store suspended sediment.