check dams; sediments;

The construction of a staircase-like system of grade-control structures (GCSs) including check dams (at least 1.5-2.0 m heights above the bed level) and bed sills (lower heights), represents a traditional approach for management of mountain streams in the Czech Republic. The sequence of GCSs usually decreases bedload transport rates andthus, affects the connectivity of coarse bed sediments in stream longitudinal direction. The application of Wolman pebble counts demonstrated downstream coarsening of bed sediments within the GCSs sequences in the 1.7 km and 2.6 km long reaches of two relatively steep gravel-bed rivers Tyra (A ? 20 km2 ; 0.01> S >0.03 m/m; W ? 10 m; 13 GCSs) and Mohelnice (A ? 40 km2; 0.01> S >0.03 m/m; W = 15 m; 18 GCSs) draining the northern slopes of the Moravskoslezské Beskydy Mts, Western Carpathians. The same situation was observed in the 1.2 km longreach of the steep headwater stream Velka Hanzluvka (A ? 5 km2; 0.02<S<0.06 m/m; 3<W<5 m; 5 GCSs).Additionally, photogranulometry together with the measurement of the largest particles deposited in small gravel bars showed independence between the local grain-sizes and calculated bankfull bed shear stresses in the 2.7 km long managed reach of the piedmountain stream Bystry (A ? 5 km2; 0.01<S<0.04 m/m; 4<W<5 m; 38 GCSs). As the result, we did not observed any downstream fining of these bar deposits although the bed slope significantly decreased by increasing longitudinal distance.