SPATIAL AND TEMPORAL DISTRIBUTION OF SEDIMENT CONCENTRATION AND PARTICLE SIZE DISTRIBUTION IN A FIELD SCALE SEDIMENTATION BASIN

摘要

The degree of uniform sediment concentration and particle size distribution at 13 spatially distributed sampling points in a 155-m3 sedimentation basin during the inflow period of six identical 100-m3 inflow hydrographs containing 454 kg of sediment was evaluated. The six events represented the sediment concentration and particle size distributions in three replications each of an unlined and a lined (no re-suspension) basin. Sediment concentrations observed at all sampling locations and up to 12 sampling times showed no significant difference during either the lined or unlined treatments. These results strongly confirm that sediment concentrations were consistent with those expected in a single, completely mixed reactor. The unlined treatment, however, yielded sediment concentrations 36% higher and the suspended particle sizes averaged 3.7 µm smaller than during the lined treatment. The increased mass of smaller particles suspended during the unlined treatment was attributed to an increased amount of re-suspended sediment.