Summary:

The last years' floods, in particular in the Upper Vistula Catchment, caused serious damages by inundations by small torrents and mountainous rivers. It was proved that hydraulic works and land-use changes usually induce an acceleration of runoff throughout the catchment, which can locally enhance erosion, damage river ecosystems and worsen floods. The "Dynamic Slow Down" concept therefore promotes slowing down, using transverse obstacles or small retention works. In accordance with sustainable development, DSD claims that hydraulic projects must be planned at catchment-scale and must take all the stakes into account, including ecological issues.
Cemagref and Cracow Institute of Water Engineering worked on from 1999 a DSD feasibility study in the Polish Isepnica catchment. In the present paper we continue the work including the simulation of the change of three sediment check in dams dry reservoirs. To deal with flood and erosion problems, they proposed small works in hillslopes and a dry reservoirs.
In the paper the DSD methods were applied to Isepnica Torrent (Soła River Tributary). Implementation consists on simultaneous management of the hillslopes and the river bed in order to slow down the runoff, to store temporally water in small reservoirs and in the areas of small risk.
The results of the simulation for three dry reservoirs (transformed sediment check dams) used are presented. The computations were done by one dimension numerical model of Saint-Venant equations. The computation results showed the significant slowing down of the runoff from the catchment and the effectiveness of the dry reservoirs