Morphological and granulometrical river bed changes along a mouth part of the Raba river (Poland)

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 ...

Characteristic of granulometric composition along chosen sand-gravel dunes within the Raba river outlet

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, ...