In the paper some the most important, characteristic parameters for vegetation density description are presented. The density of vegetation in the river beds is one of the most important parameters that has impact on the flow conditions in the river. The mathematical formulae for flow resistance and water level calculations contain the density of vegetation zone as a parameter. This parameter can be described by various methods. The compact specification of plants parameters is given in the paper. ...
The degradation of the Odra river bed is observed mainly below each last barrage of the channelized river sector Koźle - Wrocław. The mean river bed level is decreasing of some 4-8 cm yearly, causing the corresponding drop so of water surface in the river as of the ground water level in the valley. This degradation causes great problems so for navigation, as for agriculture and environment. The construction of successives last barrages Wrocław (1897), Rędzin (1922) and Brzeg Dolny (1958) had only a temporary effect. Below each of these barrages the river bed erosion continued, concerning a river reach of some 50-60 km. In 1994 Parzonka has proposed the conception of the "feeding" of the Odra just below the new barrage Malczyce (km 300,0), entering in action probably in 2012. The ad-ministration has decided in 2008, that this barrage can enter in work only after the accomplishment of important restoration works, taking in account the needs of environment, of navigation and agriculture and of the human population. The programme of restoration works provides two steps:- Step I: the elevation of the Odra bed level on the sector Malczyce-Ścinawa (km 300 - km 335) minimum by the half on the eroded ...
This paper aims to improve the reliability of the determination of flow resistance and hydraulic effects of vegetation. For this reason, laboratory flume studies with living vegetation were employed. The most notable finding was that, when compared to leafless conditions, the presence of leaves increased the friction factor up. This was strongly dependent on the flow velocity. The work shows the results of studies conducted in water laboratory the Department of Hydraulic En-gineering the Poznan University of Life Sciences and Institute of Environmental Engineering Wrocław University of Environmental and Life Sciences. Subject of research done on hydraulic was to assess the direct natural vegetation under the influence of water flow. To analyze this phenomenon adopted the model of water resistance movement on vegetation. To designate determined resistance forces in-cluding vegetation structure and flow by above it.
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Occurrence of Phytophthora spp. in Polish rivers and pathogenicity of iso-lates toward some plants were studied. Rivers Jasieniec, Pisia and Rawka were surveyed during all the year with one month interval. First 2 rivers are situated in horticultural areas in Warsaw and Łódź districts whereas the third one is running through agricultural fields and forests. Rhododendron leaves were used as the baits for detection of Phytophthora from water. Number of necrotic spots on baiting leaves was a measure of population densities of Phytophthora spp. in rivers. The occurrence of Phytophthora in water was noticed during all year with the lower density in the 3rd quarter of the year. Five Phytophthora species and taxon Salixsoil were identified among isolates recovered from 3 rivers. During all year from 3 surveyed rivers (except from Pisia in the first quarter) P. citricola was recovered as the most often occurring species. Additionally P. cactorum, P. cambivora, P. cinnamomi and P. megasperma were detected from rivers. In laboratory trials water isolates of P. cactorum and P. citricola colonized roots, stem parts and leaves of birch with the significantly faster spread of necroses on plant parts inoculated by P. citricola. In greenhouse trial both species caused root ...
Influence of water source on frequency of Phytophthora occurrence was the purpose of this study. Phytophthora spp. was detected in 3 rivers, 2 canals and 2 ponds. Rivers were situated in different part of Poland. Two of them (Jasieniec and Pisia) is following through horticulture areas, whereas Wisła - through area with hardy ornamental nursery stocks. Water canals and ponds are situated nearly or in nursery. Rhododendron leaves baits cv. ‘Nova Zembla' were used for detec-tion Phytophthora in water from March to November. Number of necrotic spots on baiting leaves was the measure of population density of Phytophthora in water. Phytophthora spp. were detected from water from March to November. In canals, the most of necrotic spots on baiting leaves were observed in May and June. In rivers Jasieniec and Rawka and water ponds significantly more necrotic spots on baiting leaves were noticed in March, April, May and in September, October and November. P. cirticola was recovered as the most often occurring species and next P. cryptogea, P. cinnamomi, P. citrophthora, P. taxon Salixsoil.
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Large river continuously transform their surroundings, causing the need to update all the documentation geodesic related thereto changes. Caused by them concern arable land in the first place. It is directly connected with the definition of land under surface of flowing water, and the necessity of updating the of land and buildings registry.This paper contains a description of the analysis conducted to verify ongoing changes in this area for over three decades. As the object of research part of the bed of the Vistula River with a length of more than 13-hundred miles was used. This segment is located in front of Krakow and has clearly signs of strong meandering.These issue which has been achieved by comparing the documentation created during the establishment of records of land and buildings in the late 70th of the twentieth century and aerial photographs taken in order to update and modernize the LPIS database in 2009. ...
This paper attempts to assess an effect of the range of regulatory works in watercourse beds on the aquatic plant communities. The results of field studies carried out on sections transformed as a result of regulatory works and the non-altered sections were compared for this purpose. The field studies were conducted in growing seasons in years 2008-2014 on 11 small and medium-sized lowland watercourses in Lower Silesia. They included identification of aquatic plant species and estimation of the degree of bottom coverage with them. The assessment was based on analysis of changes in the values of five biological indicators such as: the number of aquatic plant species, Jaccard similarity coefficient, ecological status, Shannon-Wiener biodiversity index and Pielou`s evenness index. Comparative analyzes enabled to determine the qualitative and quantitative changes in the aquatic plant communities. However, they did not show any correlation between the analyzed biological indicators and the range of regulatory works in watercourse beds. ...
