Dynamic slow down in the mountainous catchment

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 ...

Flood retention capabilities in a mountain catchments: case study of the Commune of Spytkowice

The experience of flooding from 2010 in the Commune of Spytkowice showed a dire need to define the factors behind the floods repeating every year in the region and to propose the best solutions for eliminating or limiting damage in the risk area. On account of the catchment's location in mountainous area, the main intention was to propose actions that would mainly increase the catchment retention capacity in the upper reach of the Skawa river and its tributary, Pożoga. By slowing down the flow, these actions may considerably contribute to the protection of the most flood-sensitive areas located in the lower part of the catchment. Two solutions have been proposed based on the idea of building dry water reservoirs and providing the possibility to resettle inhabitants from the flooded area. The choice of the best solution for the Commune of Spytkowice depends on the topography of the valleys of rivers Skawa and Pożoga, as well as the financial situation concerning the project. ...

Modelling of water outlet through hypothetical dam break in dam of the Rzymówka reservoir

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. ...