Summary:

Hydromorphological valorization according to Water Framework Directive is an element of support biological evaluation of surface water's ecological state. Ecological state of rivers is connected with number and diversity of species that live in them. Biodiversity of aqueous environment is depended on changes occurring in the river environment characteristics what is mostly connected with riverbeds conversions.
In this article present the results of hydromorphological valorization of section of The Bystrzyca River below Mietkowskie Lake together with its old bed. Artificially built drop channel that carries away water from the reservoir (1,4 km), old riverbed (2,2 km) which had conducted water before the dam was built and the section of river that was created by the connection of new section with The Bystrzyca old riverbed were analysed (1,4 km). The analyzed a total of 25 sections of river, 200 meters each. The naturalness degree of individual sections was evaluated on the basis of Ilnicki and Lewandowski methodology. Ecological evaluation criteria have taken into consideration riverbed morphology, river hydrology, water quality, tree cover, aquatic and banks vegetation, riparian zone and the valley land management.
From conducted research follows that with increasing the distance from the reservoir the naturalness category of The Bystrzyca River rises. The sections be-longing to the old river bed was classified as III category naturalness, however channel that carries away water from the reservoir (now an integral part of the Bystrzyca river) in 71 % include to low IV category. After connection with old ri-verbed the ecological value of the river rises - the individual sections belong to III (42 %), II (29%) and I (29%) naturalness category. Below, in km 43+000 the river is conversed by human to a small extent, which influences favorably on its higher landscape and ecological value of the area.