The area of Q10% flood in the over-flood terrace is characterized by irregularity in longitudinal valley profile. The areas of flat, bright flood terrace with small slope in cross-section appears rarely. This kind of stream will run often under deep erosion conditions and the terrace of small dimensions appears on one or both riversides depending on hypsometry and the stream situation. In these conditions the plants cover low water banks and the bushes are dominating the floods plain. This influence during the flood event causes the impact of plants on the flow. The direct effects are: the narrowing downstream and concentrating main flow area in the central part of the low water stage cross-section, changes in velocity profile on the flood terrace with plants as in the transitional plants adjacent area and in the central part of the stream bed. The plants on flood plain are contributing to increase the velocity also in the bottom zone of main channel. The subject of this paper is the analysis of water flow process inside of plants occupying the zone on flood terrace and its indirect influence on hydrodynamic stability of the main part of channel. Due to the influence of plants during ...
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, ...
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 ...
Flood risk management and river training made with use of bed stabilization techniques followed by straitening and shortening of river corridors caused increase of the fall. As the effect hydrotechnical structures emerged with the aim of utilisation of water energy by damming the water movement. Such a structures break a river's continuity and fish migrations upwards the river is impossible. Regaining river's connectivity requires use of additional hydrotechnical solutions having purpose of making possible for fish to navigate obstacle in their migration up rivers and streams. Over the time development of the solutions in the field of fish migrations leaded to variety of constructions among them only some number really functional. The necessary compromise is needed to met all the expectations for any type of the fish pass, among them minimal and maximal water velocities, high energy losses, geometrical limitations especially considering the fact their interconnected.The paper proposes separation of particular elements generating energy losses in water movement described by energy dissipation formulae. Measurements were taken on an existing rock ramp fish way on the Tuszymka River in the Kamionka settlement and consisted of fish way geometry and water velocities. Water velocities measurements location concentrated along the places with maximal ...
A common phenomenon occurring in small river basins is an increase of spatial development in the period of last 20 years. This development is an effect of economic changes in our country, resulting in growing land cover by all sorts of infrastructure as well as in changes in method of development. It may be observed both giving up the intensive agricultural use in large parts of arable areas and even greater intensification of agricultural use in some selected favorable situated locations. Those processes are of increasing character and lead to substantial changes in hydrological conditions of runoff, which imposes the necessity of verification of the functionality of the existing water regulation structures. The authors have presented issues connected with changing basin storage and determined the influence of spatial development on basin surface sealing and rainwater storage. Concepts of land use changes were presented; calculations of water storage reservoir capacity were made, as well as the influence of storage deficit and changes in forest cover magnitude on bedload transport conditions. Critical parameters of bedload movement were calculated. ...
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 ...
