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 ...
Erosion processes apart from distruction of upper layer of soil, influences morphology and hydrology of streams. Devastation of upper soil layer decreases basin retention what increases surface runoff, flood discharges and decreases low flows. Particularly bad damages in mountains basins are caused by heavy rains that have local extent but are very violent. The Wielka Puszcza basin is located on two natural regions: Podkarpacie Właściwe and Beskid Mały that belong to the Karpaty district. The basin area amounts 19,30 km2. Density of hydrographical network is 1,60 km⋅km-2, slope index 0,3102. Mean height attaines 507,5 m npm. The basin has forestry degree 81,65%, and indicator of forestry development 0,87. In the investigated basin prevail slopes above 30% (62,1%) and 20-30% (20,7%). It is lack of slopes of 0- 3%. The mean slope of the basin is 25,47%. In land use prevail forests (81,65%). There is 16,54% of arable lands, and grasslands cover 1,81% of the area. The cross sections of the channel and discharge intensity curves before flood and after flood that took place on 28 August 2005 were presented. Disasterous flows caused significant cross section area, lowering channel bottom of about 0,5 m. The change of flow intensity curve took ...
Long term observations of Upper Vistula tributaries, made by authors, showed that the narrowing and straightening of the rivers and their floodplains resulted in accelerated riverbed erosion and the increase of flood risks. River floodplains are widely acknowledged as being very important for biodiversity, therefore by their narrowing the floodplains lost their natural patterns with a consequence decline in habitat and species diversity. In the last years appeared a new approach in river management and engineering, the EU Water Frame Directive consists an important step for more ecological river training. In consequence an increasing number of restoration projects have been initiated in the last years. In the present paper the authors tried to check the possibilities of flood plain widening upstream of the Nowy Sącz City situated on Dunajec River (km: 111+900 - 107+500), where are devastated wastelands. In the urban area of Nowy Sącz the levees distance was left unchanged. For the new conditions the numerical simulation by 1D mathematical model RubarBE was carried on. The obtained results showed the significant decrease in the flood peaks upstream of Nowy Sącz and some in the town. ...
The aim of the presented researche was to examine the morphological changes of the degraded sectors of the stream Smolnik, caused by two floods. The changes of the hydrodynamic conditions were estimated because of its decisive influence on sediment transport intensity and thus on the investigated channel sector geometry. The surveying measurements of the longitudinal profile and cross sections of channel were carried out. The granulometric composition of the bed and the bank material was determined also. Results of this researche are basis for calculation and for analysis of the studied process. Volumes of material eroded from the banks and from the bed channel as well of the sediment deposited on the bed channel were calculated. The Bagnold equation was applied for estimation of sediment transport intensity. The noticed changes along the channel are illustrated by the situational outlines, where area of undercuts of banks pits and bars are showed. ...
In this paper, the data from DFO ((http://www.dartmouth.edu/~floods/) was used to evaluate recurring floods in Europe between 1985 and 2007. In last 22 years the number of floods in Europe increased approximately five times. The dynamics of factors representing an average flood in Europe shows a negative trends, at least, as far as number of victims and economic loss is concerned. This may be a sign that the population got used and adapted to this cataclysmic event. The flood forecasting is more and more precise and get to endangered people on time. In the overall picture, one should also consider the improved skills of rescue teams. ...
This article shows analyzes the possibility of reducing the 1% frequency flood wave with use of dry storage reservoirs. Analyses were carried out in the Serafa catchment, where due to a very high degree of sealing creates a risk of flooding for residents, which showed even the flood of May 2010. The increase in the degree of sealing due to faster response to the rainfall catchment area and, consequently, higher peak flows. An alternative to increase the degree of sealing the catchment are measures to improve water retention. One such method is the construction of dry storage reservoirs. In this article was analyzing the work of these variants reservoirs - in the first scenario assumed a reservoir on the Serafa river, in the second - two dry reservoirs, one on the outlet in Malinówka tributary and second - as in variant I. The capacity of the reservoirs resulted from the anal-ysis of topographic maps and digital terrain model and the small retention program for the Malopolska Voivodeship. All calculations were carried out in the HEC-HMS. In the case of the analyzed catchment was the most preferred variant II. Calculations showed that this variant is possible to reduce the maximum ...
The Krzczonówka stream is left tributary of the Raba River. In 2014, during the period from April to September, the project related to the lowering of the existing debris dam was carried out. Heavy rainfall resulting in high flows occurred shortly after the start of work. In effect, large amount of debris was moved from the reach located upstream of debris dam to the reach downstream of it. This work aims to present the influence of flood discharges on the morphology of the stream channel under conditions of high sediment supply. Observations on the changing conditions of water flow and sediment transport will also be presented ...
