Summary:

The Nida River flows trough the southern part of Poland. The basin of this river is localized mainly in Swietokrzyskie province. It is a longest river in this province (151.2 km) flowing in it's upper part trough the southern part of the Swietokrzyskie Mountains. In most part Nida is a not regulated lowland river, characterized by the slope of about 0.65 promiles. The Nida River valley between cross-sections Stara Wies and Pinczow had been strongly transtormed. Between villages Stara Wies and Motkowice, the typical river training had been done. The river also was partially trainned on the distance between Motkowice and Pińczów as well as in the short distance below Pinczow. The Nida River embankments are localized in the middle part so a big part of the river valley cannot be used as a small retenition. These narrowly distributed fortiffications are in a weak condition, what causes that spring flood waves which often reach the top of the embankments can easily destroy the embankments and flush onto the valley some of their parts together with the sandy substratum from below. The water flowing trough the destroyed part of the embankment transports the high volume of sand from the riverbed which, after the pass of floody flow, deposites on the river valley. Also the water cannot easily go back to the river channel. Both of those phenomenons are disadvantageous because of the landuse of this area as a feeding grounds and meadows. For improving of the current state, the renaturalization works are proposed. In the area of middle delta the long term measurements in situ and field reconaissance have been performed since 2003 by the scientists of the Department of Water Engineering, AU Krakow (bathymetry in river channel and in the river valley, flow velocity measurements and bedload characterization). After the flood in 2006 the main attention was focused on the region where damages of embankments were found. There were two damages between Stara Wies and Motkowice. First of them was localized in cross-section 76+840, and the second in cross-section 76+640, about 500 meters upstream from the bridge in Motkowice. The main goal of this paper is to present the current use of the embankments of the Nida River in on th esection km 78+300 – km 76+200 after the 2006 spring flood. Also the prognosis of the flood risk as well as the results of the flooding after the renaturalization works is presented. The land use of the presented area was compaired to the other parts of the middle delta and to cross-sections localized downstream.