Determination of areal sedimentation rates in rivers by using plate sediment trap measurements and flow velocity—settling flux relationship

Not much is known about sedimentation of organic particles in rivers. Plate sediment traps deployed in fast flowing River Spree and in a slowly flowing side arm yielded trapping rates between 0.7 and 52 gDW m−2 d−1. A linear regression between flow velocity and trapping rates was used to extrapolate from point measurements to areal average trapping rates, which were 11 gDW m−2 d−1 in the side arm and 1.4 gDW m−2 d−1 in the free flowing river section. These rates are typical for the River Spree, but different from other rivers. The plate trap measurements provide the basic variables for the sedimentation rate SED=C•Ws*(1−V/Vcrit,sed), i.e. concentration of particles (C), sinking velocity (Ws), flow velocity (V), and a threshold velocity (Vcrit,sed).