The aim of the paper is to predict a morphological changes of the riverbed on a section of the Skawa River within back-water reach of Świnna Poręba water reservoir. The increasing bed level which is a result of deposition of bed material, have influence on water surface elevation during flood and can threaten surrounding areas. Between spring 2003 and summer 2006 carried out measurements which consist of: survey measurements of a section of Skawa River, granulometric composition of the bed material, velocity profiles and measurements of the water surface elevation during flood events. Prediction of the morphological changes was possible using twodimension CCHE2D model developed by the University of Mississippi. The numerical modeling focused on the simulation of historical flood events, t-year discharges with probability between p=50% and 0.1% under different water levels in the reservoir ranged between 304.56 m a.s.l - without back-water effect and 309.60 m a.s.l. - normal water surface level. The simulation runs included bedload and suspended load transport which caused of bed elevation changes. Back-water reach, where deposition take place, depends on reservoir water surface level can extend up to a distance about 1.5 km. Numerical results of forecasting of fluvial processes on the studied ...
The river channels exploitation leads directly and indirectly to they river training. The usual consequences of that is a dramatic change of river dynamics. Thus in the studies – especially field studies – which can show the better explanation of river forming channel and river processes are the key elements when one intends to talk about river renaturalization and river rehabilitation. In the following paper the results of investigations of morphological changes within the outlet of sand-gravel river are presented just after the bankfull. Also the granulomerty of the considered river channel material was taken into account. On the base of very detailed field survey done along a mouth unit part of the Raba River situated in front of Polish Carpathians, the authors provided the analysis of morphological and granulometric changes of the river bed and channel. Under the consideration the authors took river bed forms, ricer bed armoring and sub-pavement granulomentry as well as river geometry of the particular cross-sections. Work was done (and is continued) within the years 2005-2006 but only the data from 2005 year are presented here. It was fund that along the research channel many new so called riffle and pool sequences are present as ...
The paper summarizes the results of the work done in orders to evaluate the possibility of changing the function and utilization of rubble dosing dam on the Wieprzówka I mountain stream in order to create an artificial lake and ensure that the water level in the reservoir remains the same. The artificial lake will be valuable from the point of view of tourism and what is more it will improve the water retention of the valley. A rubble dosing dam protects the river bed by reducing the bed slope and water velocity and what is more by controlling the bedload transport so that accumulation takes place up the dam. The dam does not stop bedload transport because there are openings which dose the fine material. The fine material can be transported even if the rubble dosing dam is filled up, so the hydrodynamic equilibrium and the connection between upstream and downstream sections of the river is maintained. Hydraulic seal of the rubble dosing dam and the exploitation of accumulated bed material will break the hydrodynamic continuity of the river channel and cause erosion below the dam – a process against which the dam should protect. Field measurements carried out on ...
The paper presents results of calibration and verification of one-dimension numerical model of the Wislok River from Besko reservoir to the estuary to the San River. In order to evaluate the quality of this model following coefficient were used: the correlation coefficient, special correlation coefficient, total square error and errors of culmination level, culmination flow, culmination dislocation and flood wave volume. Observations of water levels in the Wislok River are conducted on 5 river gauges. An 5 another gauges are located on the tributaries of the Wisłok River. The ve-rification and calibration process carried out on the waves in 1987 and 1998 al-lowed to confirm the correctness of the hydraulic model in the sector from the river gauge Besko to the Rzeszow river gauge. Between Rzeszow and Tryncza river gauges volumes of waves are not balanced which enforces the admittance in the hydrological model of negative values of a lateral inflow. The volume of 1987 flood wave in the node of the three river gauges in Wislok-San system indicates that the wave is balanced on the Tryncza stream gauge.The performed simulations of the flood wave transformation on the whole Wislok River for different computable scenarios, with usage of hydro-informatic software - ...
1-dimensional models, e.g. HEC-RAS, MIKE 11 are used to calculate water surface elevation concerning probable discharges for flood hazard areas designa-tion. Hydro-informatic software programs HEC-RAS and MIKE 11 are used for modeling of water discharge in the river bed and in the river valley, with engineer-ing objects of complicated structure (bridges, culverts, weirs etc.). The following stages of modeling may be distinguished: schematisation of water network, geodetic measurements of the river bed and engineering buildings, identification of roughness coefficients, hydrological calculations of discharges in selected profiles of the modelled watercourse considering the boundary conditions, numeric calcu-lations with calibration and verification of the model as well as visualisation of the calculations' results. The paper presents the results of modeling of a sector of The Lubcza River in the Wislok basin having length equal 8,7 km (uncontrolled basin), in which 17 bridges and 12 weirs are located. The elevations of the water surface for di-scharges of the defined probability of exceedances and the Digital Model of the Water Surface (DMWS) are the basis for the analyses and comparison of the obta-ined results. Flood hazard areas occur on the intersection of the Digital Terrain Model (DTM) and DMWS. The knowledge of water ...
The aim of presented research was evaluation of hydrodynamic conditions changes on the regulated sector of the Smolnik stream. The measurements were carried out in 2008 and 2009. Each series of this study included measurements of the longitudinal profile, cross-sections of channel and the bed material granulation. Results of these works were used to calculate the hydrodynamic quantities as mean velocity, stream power, shear stresses and bedload transport (by the Bagnold equation). It was possible to ascertain that the control works came to expectation and bank erosion was stopped. Locally an intensification of bed erosion had place. An analysis of the longitudinal profiles and course of grain-size composition of the bed material changes proved, that 2 years after control works realization tendency to return to early hydraulic conditions was appeared.
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The paper presents measurement and calculation results of volume samples taken from the bedforms of the sand-gravel bed river in Polish Carpathians. As a sample method the “in situ” sample freezing method was applied. River channel geometry and changes in the morphology of the river bed were investigated using laser geodimeter. The procedures have been carried out on the Raba River downstream of its confluence with the Vistula River. The main research was conducted in spring and autumn 2006. To give a picture of the long term processes which have the influence on the changes of the river bed along the investigated reach for comparison some of the results from year 2005 are also presented. The basic information about research catchment, its location, gravel sampling methodology and characteristics of sand-gravel dunes are included. Development of riverbed forms as a mixture of sand and gravel according to their granulometric composition was detailed. The samples were analyzed considering the layered structure of the dunes and the results of statistical calculations are provided. Tables of granulometric parameters in metric and logarithmic scales are presented among other information such as: mean diameter, sorting index, sorting degree, coefficient of grains uniformity and non-uniformity, standard deviation, ...
Using rivers and mountain streams for economic purposes led to the loss of ecological balance and to the intensification of morphological processes, which in most cases caused erosion as well as the lowering of riverbed. Such changes have made stabilising the river bed and its banks necessary. In our work, on the basis of the analysis of project documentation and the simulations of flood events on several mountain streams, we made an attempt to answer the question: are the river training works enough to let the catastrophic floods pass safely and do they take into account the morphological processes which have a formative influence on the riverbeds? It has been proved that as far as hydraulic structures are concerned, the adjustments that are being planned comply with the requirement of ensuring the required capacity of the river channel. Maintaining the required capacity of the river channel creates the need for constant remedial works. When dimensioning cross-sections with stable bottoms, the width of the river valley is a serious limitation which, in urban environment, does not allow the engineers to design a crosssection of a river channel whose shape would be most efficient one. In case of river channels with moveable ...
Detailed recommendations formulated by European Commission in 2007 introduce new regulations regarding the continuity of river channels. The existing hydraulic structures should be equipped with fish ladders in order to keep the fish restitution conditions and the new hydro-technical structures should assure tech-nical solutions that do not cause any change in hydro-morphological state. Ac-cording to the Fisheries Institute the following conditions of biological stability should be followed to keep the biological stability conditions for diadromic fishes:- an alluring stream criterion,- a terminal velocity criterion,- a criterion of admissible fish ladder filling,- a criterion of admissible loss Δh for the transom ladder discharge.The paper presents results of numerical modeling of 400-meter sector of a river that includes coated weir, small hydrostation and a fish transom ladder. The action taken concentrated on such formation of the discharge in the ladder and modification of the bed configuration in the hydro mouth that creates the alluring stream. Numerical modeling results were compared to results of calculations by empirical formula.
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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. ...
