A forecast of silting was developed for a small water reservoir on a watercourse not included in hydrological observations. Lack of data on the flow volumes, sediment concentration and suspended load transport suggest the use of indirect methods. These make possible determining the amount of sediment amount supplied to the reservoir. Studies on silting volume covered a reservoir at Narożniki situated on the Dęba stream. The methods of Reniger-Dębski, Brański and DR-USLE method were used in computations of sediment supply to the reservoir at Narożniki. Field studies were conducted to determine the way of management of the studied reservoir catchment. The kind of ground and its composition in the agriculturally used areas and forest sites were determined. The results of field works made possible to fix the parameters of the universal soil loss equation, which is the basis for computations using DR-USLE method. The silting degree computed on the basis of the reservoir silting measurements is 0.58%. The reservoir silting in successive years of its operation was calculated using Gončarov formula. The results of silting forecast after four years of operation were compared with the results of measurements. The highest compatibility of results for silting forecast developed on the basis ...
Determined were the volume of river sediment captured in a water reservoir at Wilcza Wola on the Łęg river. The water reservoir with 3.86 mln m3 capacity was put into operation in 1989. Silting measurements were performed after 10, 13 and 14 years of operation. Computed reservoir silting ratio were respectively: 13.08%, 15.79% and 16.20%. Samples of bottom deposits were collected to determine their physical and chemical properties. Determining of heavy metal concentrations may provide a basis for the sediment quality assessment and their potential applications in the environment after extracting from the reservoir bottom. Contents of harmful substances assessed in the sediments were compared with limit values permissible by the decrees of the Minister of Natural Environment Protection, Natural Resources and Forestry guidelines and criteria suggested in the foreign literature of the subject. The sediments from the water reservoir at Wilcza Wola are characterized by a low content of heavy metals. According to the Decree on soil quality standards [Joural of Laws, No.65, item 1359] none of the values established for the studied elements were exceeded. According to German guidelines threshold values of heavy metal concentrations in bottom deposits are between twice and thrice higher than those obtained in ...
Within the framework of the small retention program location of 65 reservoirs and 4 polders was determined. Their total capacity will permit retention of 38 hm2 water and the estimated cost of building was about 1,03 mld złote [„Program małej retencji…” 2004]. Small water reservoirs undergo quick silting and the time laps of their silting is hazard to define. The paper presents possibilities of forecasting of small water reservoirs silting basing upon data gained from measurements of silting quantity from years 1969–1983 and 1999–2006. Two reservoirs at Zesławice i.e. the main reservoir before and after desiltation and the sidereservoir which was passed over for exploitation after desiltation of the main reservoir. The paper aims at determination of the influence of the side-reservoir on silting intensity decrease in the main reservoir. The time laps after which the reservoirs will be silted in 80% was calculated. Forecasting of water reservoir silting was made according to Gončarov’s formula. Determination of the quantity of load deposition after the first years of exploitation - R1 cause of principal difficulties in elaboration of forecasts. Disposing of measurements of silting quantities in consequent years this quantity was calculated after transformation of the equation to the form permitting ...
The assessment of sediment amount transported by river based on indirect methods may lead to considerable errors. It particularly pertains to the assessment of transported suspended sediment quantity. In the paper methods are presented of determining the amount of load transported by the river and supplied to the water reservoir at Krempna on the Wisłoka river. The quantity of load flowing into the reservoir determined on the basis of field measurements was assumed reliable in the assessment of applied computational methods. On the basis of results of the multi-annual investigations on the silting processes, the authors, set a value of β-parameter using the results of the silting volume measurements and load transport computations during the subsequent years of the reservoir’s operational period. The sediment trap efficiency of the reservoir determined on the basis of transported sediment mass computed according to bathometric measurements and silting surveys ranges between 65% in 1998 and 50% in 2005. The determined sediment trap efficiency on the basis of the results of calculations by the DRUSLE method is on about 30% larger than the sediment trap efficiency value calculated on the basis of bathometric measurements. The amount of sediment transport computed by the MUSLE method is ...
In the world professional literature can find many formulae and the nomograph using to apprise of sediment trap efficiency of water reservoirs. Sediment trap efficiency of water reservoirs, introduces in the form of nomograph or formulae, is defined in the function of the coefficients which they are the most often: capacity- inflow ratio – C/I and capacity-watershed ratio – C/W. The reservoir sediment trap efficiency is determined from Łopatin’s, Drozd’s, Karaušev’s, Brune’s formulae in dependence on the capacity-inflow ratio. The C/W ratio is used methods of Brune-Allen’s, Brown’s and Gottschalk’s. Churchill defined the reservoir sediment trap efficiency in function of sedimentation index. Qualification of sediment trap efficiency of small water reservoirs creates considerable difficulties, because the majority of existing formulae and nomograph using to apprise of sediment trap efficiency was worked out in the result of the investigations of large and middle water reservoirs. The results of real sediment trap efficiency of the small water reservoir βrz in the following years of operation were introduced in this work. Sediment trap efficiency was qualified on the basis of several the measurements of silting and on the basis of calculations of the quantity of suspended sediment delivered to the water reservoir. The ...
Erosive processes are the limitative vitality of water reservoirs in catchment areas. Considerable quantity of the delivered erosion products to rivers are deposited in artificial barrage reservoirs. Qualification of the silting volume of small retention reservoirs in time of their operation and indication of the proper methods of silting forecast is a particularly essential engineering question especially in relation of the realized programme of small retention. The measurements results of silting of twelve small retention reservoirs being in the river-basin of the Upper Vistula were introduced in this paper. The determined mean silting degree of studied reservoirs carries out from 0,06 % to 6,38 %. Detailed silting forecast of four chosen water reservoirs was presented, two situated on water-courses with hydrological control - reservoirs Krempna and Maziarnia, and two situated on water-courses not included hydrological observations. The aim of the paper is appraisal of the possibility of silting forecast of small retention reservoirs by help of Gončarov’s and Šamov’s empirical formulas and on the basis of the determined intensity of silting according to Schoklitsch’s and Piečinov’s formulas. The capacity- inflow ratios - α, capacity-watershed ratios – C/W of studied water reservoirs were marked. This coefficients made it possible to qualify ...
The many years' measurements of silting the small water reservoir, closing the cachment covered loesses soils, allowed on the change qualification of the silt-ing degree during operation. In this work was compared the archival data from the measurements of silting the water reservoir in Zesławice, executed in the pe-riod before his desilting, with the results of measurements executed after desilting and building the side assistant reservoir. Water reservoirs in Zesławice are characterize the high intensity of silting. The Annual mean of silting ratio of res-ervoirs carries out: 3,0 % – the main reservoir before desilting, 1,87 % – the main reservoir after desilting and 1,00 % – the side assistant reservoir. Disposing the volume of sediment stopped in reservoirs the coefficient of the mechanical denudation was counted, definite by Wiśniewski as the relation of the volume of sediment deposited in the reservoir to the catchment area. The defi-nite approximate value of the denudation, for the help of this coefficient, proved considerably diverse in the individual years in which the measurements of silting were made. The mechanical denudation coefficient was counted for periods before and after desilting of the main reservoir. The results of the calculations of the transportation of ...
Small water reservoirs are silted in the considerably shorter time in the comparison with average and large reservoirs. Considering the silting process de-silting work every dozen or years are carried out. Desilting of small water reser-voirs follows after the lapse of the considerably shorter time of operation than it to result can from the Hartung's criterion, according to whose reservoir not fulfils one's the function because of silting making up 80% of his origin capacity. The example is the reservoir in Krempna, which was desilted after eighteen years of operation, when his silting, determined for the help of the degree of silting, 41% carried out. The redevelopments of the reservoir were also executed during of de-silting works in 2006, reducing his capacity from 112 thousands m3 to 96,3 thou-sands m3. Execute the silting measurements in 2009 and stated that the degree ratio is equal 7,0 %. It was worked out the relationship between silting ratio and the time operation of the water reservoir in Krempna, definite on the basis established silting ratios of the reservoir in individual years before and after desilting. On the basis of this relationship was stated that the course of the silting process will take place ...
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 ...
