Evaluating Rare Earth Elements as Tracers of Fluvial Processes: Fine Sediment Transport and Deposition in a Small Stream

Highlights Natural sediments labeled with rare earth elements can effectively be used as tracers for quantifying fine sediment transport and deposition. Two artificial floods in a small stream (100 ha watershed, 1.5 year return flow of 515 L s -1 ) transported 0 m to >850 at maximum rate 55 . Sediment deposition per unit area was greater the channel than near-channel floodplain. Use two distinct demonstrated resuspension extent during sequential high-flow events. Presence large wood associated reduced streamflow rate, decreased suspended velocity, increased deposition, near-floodplain Abstract Effective management requires an understanding lag time between best practice implementation observable changes target water body. To improve our times, we tested method label locally sourced quantify flow-through storage fluvial systems. We injected lanthanum ytterbium into flood During floods, collected quantified floodplain four cross-sections within study reach. down-gradient (90 850 m) time-integrated samplers evaluated total travel distance. tracer observations particle distances ranged from least s-1 (stream s-1). The majority mass entered first 69 Some particles that deposited following were resuspended either downstream or redeposited Our results support further use inform quality models, provide estimates times actions improvements. Keywords: Fine sediment, Flood, Fluvial geomorphology, Lag time, Large wood, Rare elements, transport, Tracer.