The aim of the paper was to study an initial evaluation of flood risk of Dłubnia river catchment, on section from its sources to Zesławice reservoir. The aim was realized basis on calculations of flows with probability of exceedance in eight cross-sections on Dłubnia river and its inflows. In these cross-sections a group of authors is planning installation of automatic water stage stations. In two of them in autumn of 2014, there were already installed devices for automatic water stage measurement. In all cross-sections, basis on made geodesic measurements, the maximum capacity was made, which was then compared with values of flow with probability of exceedance. Got results were basis to study an initial evaluation of flood risk in Dłubnia river catchment. It was shown, that flows with probability of exceedance equal 20% are not within in the stream channel and its inflows, what signalizes a flood risk. ...
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 sedimentation index was introduced and defined by Churchill. This index is the ratio of the water retention time in the reservoir and the average flow velocity of water through the reservoir. Churchill developed sediment trap efficiency (STE) of reservoir in the function of sedimentation index. The ability to use the sedimentation index to characterize the silting process of small reservoirs, as well as the possibility of using the Churchill's method was made on the basis of the results of four small reservoirs. For testing two reservoirs in cascade and two reservoirs parallel configuration were chosen. It has been found that it is possible to use the sedimentation index to determine the initial sediment trap efficiency of small reservoirs, regardless of their relative position on the watercourse. It is not possible to determine reduce the STE of the individual years of operation using the Churchill's formula. It has been shown that in the reservoirs in parallel configuration the sediment trap efficiency is reduced with the same intensity, but in the reservoirs in cascade in the upper reservoir sediment trap efficiency is faster reduced than in the lower reservoir of the cascade. Also elaborated silting intensity dependence of the sedimentation ...
The possibility of enlargement of the flood safety of drained terrains of locality Zarzecze using the storage reservoir, accumulating the excess of flood waters was introduced in the work. The worked out conception of the chapter of waters from the ditch R to the pumping station channel was also presented. The lock of the valves of embankment sluices leading the waters of the ditch R to the Vistula river follows in flood conditions, by increasing the level of the water in to the Vistula river. It comes to the outflowing of water from ditch R and submergence of the terrains of the settlement Łączany-Zarzeczein the consequence of the permanent supply of water to ditch R and damming up of water in ditch in the result of the lock of the embankment sluice. In the order to attain o reduce the risk of submergence of these terrains the creation of the storage reservoir from the pumping station channel was proposed. This channel leading water to pumping station Zarzecze. Capacity of storage reservoir and the time of filling up were qualified, founding steady the supply about flow intensity equal to 2,13 m3 ∙ s-1. It was statement that the current technical condition ...
Despite the various categories of defining the life of water reservoirs, the notion life of reservoir most often relates the period of the operation to such silting degree that makes impossible the realization of the tasks of the reservoir. In this work it was show the change of the value of the silting degree and sediment trap efficiency of chosen reservoirs and was estimates the time after which small water reservoirs will be silted in 50%. This is the period, which by Pitt and Thomson [1984] is defined as HLT, i.e. half-life time. The following reservoirs were chosen to studies: Krempna on the Wisłoka river, Zesławice on the Dłubnia river and Cierpisz on the Tuszymka river. The elaborated silting forecast of the change of the silting degree, make by the Gončarov's method [Wiśniewski, Kutrowski 1973], made possible the qualifi-cation the HLT silting time of small water reservoirs. It was stated that the life of studied reservoirs carried out from 17 to 40 years. The differentiation of the HLT value results from the hydraulic conditions of the inflow and flow through the re-servoir of the water and sediment which one can characterize in the very general method using the sediment trap ...
The results of the calculations of the conveyance of the channel of the river Dłubnia and the weir at Bieńczyce located in the km 6 + 560 of the river Dłubnia were introduced in the work. The results of calculations made possible the indica-tion of the cause of flooding the adjoining terrains during the flood in 18 July 2010. Taking into account outflow from reservoirs in Zesławice in this day to the weir the inflow in the river Dłubnią carried out approximately 70 m3•s-1. This water flow is qualified as the waterside flow. It was showed that this flow would not overflow from the channel Dłubnia below the studied weir. The weir at Bieńczyce is characterizes the smaller conveyance. It was stated that the conveyance of the weir carry out 50.25 m3∙s-1. It was calculated by the assumption that the weir gates will be fully upraised and not making up the obstacles in the overflow of the weir. However the conveyance carries out just 44,61 m3•s-1 accepting the hydraulic scheme, corresponding to the constructional solution of weir locks. It was also stated that because of the conveyance of the weir, smaller than the waterside flow, avoidance of submergence of terrains ...
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 ...
In the article, analysis coefficient of reduction of annual maximum flows for San, Wisłok and Wisłoka catchments was made. Basis of executed analysis was data about annual maximum flows from years 1984-2009 got from IMGW PIB in Warsaw. Data were verified in view of its homogeneity and then, values of maximum flows with probability of exceed were calculated, based on Pearson III type distribution with use maximum likelihood method of parameters calculation. Values of coefficient of reduction of maximum flows were calculated with use following methods: segment values, correlation and dimensionless charts. Analysis showed, that values of coefficient of reduction of maximum flows were statistically significant depending on used method (the highest values were got for method of outliers values). Value of coefficient of reduction depends on the probability of flows -increases with probability increasing. In practical hydrologic calculation, in analyzed area, coefficient of reduction of maximum flow calculated with use method of segment values should be used, also it should not be taken values of n coefficient amounting 2/3 given by Dębski.
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