ZLV Online

Abstract

Forestry practice uses for determining a proposal 100-year-flood discharge the Dub-Němec model. Coefficients of the model, i.e. n, A, are usually assessed by the graphical method, and no theoretical calculating procedure for x coefficient has been elaborated so far. The study gives a new hydrologic procedure of n, A, x parameters calculation by the Dub empiric method determining peakflow discharge of floods in watersheds with mixed types of vegetation. The study comes from analogous catchments, i.e. from the catchments with the close or the same physical and geographical conditions. The main result was presented by forest influence on decrease of flood peakflow discharge in comparison with other non-forest areas. The reliable value of that decrease equals to 10–20%, the submitted study refers to 15%. Choice of analogous watersheds in special geographical region is difficult, and it requires sizeable selective work. The model has a great practical importance for proposing dimensions of torrent-control constructions and forestry water structures. The paper also shows that forest influences on flood discharge cannot be leaved out either in forestry-structures projection or regional water management studies in agriculture-forestry landscape.