HYDRAULIC MODELING OF BED-LOAD TRANSPORT IN GRAVEL-BED LABA RIVER

On the basis of a field study of a piedmont braided reach of the grave l-bed Laba River, in the northern Caucasus, Russia, an undistorted 1:5 0 scale mobile bed hydraulic model was constructed in an outdoor exper imental plot of the State Hydrological Institute, St. Petersburg, Russ ia. Channel and hydraulic regimes of the Laba River were studied in th is model. Attention was paid to the regime of bed load transport and i ts relation to the hydraulic characteristics of the flow. The same pro blems were investigated in an 100 m long, 1 m wide flume with glass wa lls also located at the State Hydrological Institute, and in an 18 m l ong, 2.46 m wide steel tilting flume at HR Wallingford Ltd., U.K. Quan titative characteristics of bed load transport were obtained from the laboratory experiments and compared with the field data. Proximity of the field and scaled up laboratory data demonstrates that the processe s of bed load transport of gravel-bed rivers can be faithfully reprodu ced in small-scale models and flumes.