Fluves monitors since November 2015 continuously a sediment trap with dimensions 200 × 20 meters managed by the Flemish Environmental Agency (VMM) in Belgium. The continuous follow-up of sedimentation of the trap provides insights on temporal and spatial evolution of trapping efficiency. VMM will use the insights to optimize operational dredging decisions the trap and for optimizing the design of future traps. The installed measuring system is based on distributed temperature sensing with a fiber optic cable of more than 2 km. A digital terrain model (DTM) of the sediment trap is transmitted to the client on a hourly to daily basis. Results after winter floods from November 2015 till February 2016 show a significant spatial variation in sedimentation through the sedimentation trap. Also, zones with different temporal evolution of filling of the trap could be observed. The technique shows great potential for detailed spatial and temporal observation of sedimentation processes in large areas.