Summary:

The work concerns analyses of the water outlet through the hypothetical dam break in the dam of the dry reservoir „Rzymówka" on the river Kaczawa, which is currently in the project. One analysed two variants of dam erosion: overflowing water through the dam crest (variant 1) and hydraulic piping (variant 2). In the modeling one took into account different breach parameters based on parametric methods. The results of numerical simulation shows, that in case of the overflowing water through the dam crest will arise the dam break about width 74-78 m, and the duration of washing will be 0,8-2,1 h. However, if the dam break will be created as the result of the hydraulic piping, width would carry out 75 m. Magnitude of the water outflow through the gap has estimated on level 2337-2597 m3/s for variant 1 and 1590-2492 m3/s for variant 2.