The first part is the distribution of water courses, flood definition, focusing on flash floods, and a description of factors that affect the size of the flood. The purpose of the thesis was was assessment of the basic morphological and hydrological characteristics of the wathershed Bystrá, comparison capacity flow profiles (bridges) with Q100 and flow profiles (PP) Q50 calculated by Dub. 18 of the 19 bridges can not transfer to the flow Q100, 14 bridges not transferred even Q50 and 5 of them Q20. 3 of 4 flow profiles (PP) safely transferred Q50. Only No.3 profile does not transfer Q50, they transfer max. Q31. That could have been prevented flooding, it is necessary to prevent the build makeshift bridges, respectively create the appropriate place correction dam and dry reservoirs, which would serve to mitigate the high water wave.