headwater stream, bedload transport, flysch, Moravskoslezské Beskydy Mts

Our contribution summarizes results of incipient of bedload transport research conducted in small headwater streams in region of Moravskoslezské Beskydy Mts. (flysch Western Carpathians). Two methods were applied: flood competence method and marked particle displacement method. The first one presented measuring of diameters of largest boulders (200-400 mm) stored in to fluvial accumulations during Q 20-25 flood event (5/2010). By contrast, transport of marked cobbles (18-152 mm) was evaluated between 11/2010-7/2011, when some smaller events in local torrents occurred and maximal observed discharge was equal to bankfull stage (Q 1 -Q 2 ). Relationships between grain diameter and critical conditions (unit stream power, unit discharge and bed shear stress) for incipient of motion of bed coarse sediments were developed.