Prognosis of sediment inflow to Włodzienin retention reservoir on river Troja

Paper concerns the Włodzienin retention reservoir on river Troja located in Opole Province. Main function of this reservoir is flood protection and agricultural irrigatin. Reservoir capacity at NPP is equal 4 mln m3, and flood surface 86 ha. At present construction of this reservoir is near, and start of tankage is foreseen towards the end of current year. The authors presented on the paper prognosis of sediment inflow to reservoir. Calculations showed that this reservoir has been deposited after about 100 years. ...

Spatial distribution of bottom sediments in the small water reservoir at Zesławice

The study and the qualification of the spatial distribution of accumulated bottom sediments in small reservoirs is considerably not only on the design stage, but also during the of operation. The majority of investigative papers concerns to the distributions of the accumulated sediments in average and large water reser-voirs. In this work was introduced and describes for the help of the Dendy's method the spatial distribution of the accumulated sediments in the main water reservoir at Zesławice in the period before and after his desilting.In consideration of building the side reservoir, which to take of the functions of the main reservoir in the period its desilting and reconstruction, the conditions of the flow of the water and the sediment was change. It is had the impact on the dis-tribution of the bottom sediments in the main reservoir.It was showed in this work, on the basis of the executed measurements of silting and the determined the silting degree of the main reservoir, that the decrease the intensity of silting studied reservoir had taken place in the result of the split of water and sediment and it also influenced on the change of the spatial distribution of the sediment deposited. It was ...

The silting forecast of water reservoirs at Brzóza Stadnicka and at Brzóza Królewska

The work aimed at the determination of the silting degree and the silting forecast for water reservoirs at Brzóza Stadnicka and at Brzóza Królewska, which are situated on hydrologically uncontrolled Tarlaka stream. The analysis took into account the influence of upper reservoir - Brzóza Stadnicka - on the amount of se-diment flowing into the lower reservoir - Brzóza Królewska. The analysis of the silting process was carried out in three variants. The first one concerns to the Brzóza Stadnicka reservoir, the second to the Brzóza Królewska reservoir, without taking into consideration the upper reservoir, and the third variant took into ac-count the influence of the upper reservoir on the lower one. It was stated that stu-died small water reservoirs were characterized relatively low values of the sediment trap efficiency what causes extension of their useful life. Sediment trap efficiency of Brzóza Stadnicka reservoir determined on the basis of the balance of the volume of sediment delivered and deposited in this reservoir is carried out 27.9%. The somewhat higher value βrz = 38.7% the Brzóza Królewska reservoir is characterizes. It was also stated that the upper reservoir of the cascade had the in-significant impact on decrease of the silting intensity ...

Appraisal of the possibility of the use of the Brune method and its modification for the assessment of the sedyment trap efficiency of small reservoirs

The results of the calculations of the sediment trap efficiency of small reservoirs were introduced in the work. The sediment trap efficiency was appointed the symbol . Nine small reservoirs located in the Upper Vistula river basin were chosen to analyses. This efficiency became determined on the basis of the sediment balance and compared with the results of applied Brune's method and its modification, worked out by Gill, Heinemann and Jothiprakash and Garg. It was stated that the possibility of the use of these methods to delimitation of the initial sediment trap efficiency of small reservoirs existed. The initial  concerns to the beginning of operation. These methods can have the use in the case of the small reservoirs the whose capacity-inflow ratio is larger from 1%. Also it was stated, that the results of the calculations of the sediment trap efficiency in the successive years of the operation of small reservoirs executed using Brune's method and Gill's, Heinemann's and Jothiprakash's and Garg's formulae they do not represent real value of , determined on the basis of the sediment balance. Estimated methods can not the be used to the qualification of the sediment trap efficiency of small reservoirs in ...

THE STUDIES ON CHECK DAM RESTORATION EFFECTIVENESS

A check dam is a hydraulic structure, which is constructed in order to limit river sediment transport. A sedimentation reservoir is created upstream from the body of the dam, where river sediment is constantlyaccumulated. These structures were constructed starting in the early 20th century in upstream parts of mountain streams in the Polish part of the Carpathian Mountains. At present, the reservoirs of most check dams are already fully filled with sediment and the impact of these structures on the ecosystems of streams is unfavorable. Moreover, the dams that have not been renovated are in poor technical condition. In the paper two cases of check dam lowering and restored is discussed and the one hypothetical case of gradual check dam lowering is presented and discussed as well. The cases of Krzczonówka and Trzebuńka, where the method ofremoving sediment from reservoirs was different, showed that the sudden change of „established" hydrodynamic conditions for decades is not favorable for the stream. The results of hypothetic simulation of gradual check dam lowering for the case of Isepnica Stream leads to the conclusion that lowering the construction of check dam and removing sediment from its reservoir in a way that does not have a ...