Possibility of application theory of fuzzy sets is considered for the decision of task determination character of flood floods. Unclear description of factors influence is entered on the scales of flood flood. On the basis of such description the method decision-making at determination scales of flood floods is developed. The results of determination character of flood floods are resulted at four different sets of values factors influence on floods. It is rotined, what unclear values of factors influence are determined by the scales of flood.
flood flood, scale of flood, unclear description, factor of influence