Non-destructive Measurements of Fine Sediment Infiltration Masses in Laboratory Experiments

Fine sediment infiltration into interstices of a riverbed has been investigated intensively in both laboratory and field experiments given its high impact on riverine ecology. The clogged pores influence the exchange between surface water and ground water, alter interstitial habitats for benthic organisms and also the reproduction habitats of gravel-spawning fish. So far, most laboratory investigations measured sediment infiltration masses using destructive methods, which allow only for the assessment of fine sediment infiltration masses at the end of experiments but not to investigate the dynamic behavior of clogging processes.

In this study a non-destructive method based on Gamma Ray Attenuation (GRA) is presented to measure fine sediment infiltration masses in laboratory experiments. Therefore, preliminary box experiments and flume experiments were conducted to proof the concept of the measuring technique and to tests its repeatability. To test the feasibility of GRA, a comparison to previously weighted infiltration masses was conducted yielding in deviations within a range of 1.5% to 4.8%, while the repeatability of the flume experiments yielded deviations between 3.7% and 5.6%. These promising results show the high potential of the GRA method for future experiments dealing with the phenomena of sediment infiltration and accumulation, especially in relation to the dynamic behavior of clogging processes.