8 research outputs found

    Assessment of river bed evolution with the aid of 2D hydrodynamic model with integrated sediment transport modeling capabilities

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    The aim of the study is to assess hydro-morphologic evolution of currently cut off meander for 3 river restoration scenarios during 10 days of bank-full discharge. To simulate hydro-morpho-dynamics, a numerical model with movable bed, R2DM is used. Results for scenario with partially opened meander indicate aggradation at inlet of meander and 10% decrease in flow rate. Scenario with fully opened meander shows aggradation at the inlet and 55% decrease in flow rate. Full diversion scenario results in formation of natural river landforms (point bars, cut banks, pools, riffles) and stabilization of river bed evolution

    Predicted occurrence of ancient coppice woodlands in the Czech Republic

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    Coppicing started in the Neolithic period and has been practiced throughout European history. This traditional silvicultural system was abandoned in many European countries during the 20th century. The Czech Republic now has a very low proportion of coppice woods (CW), as more than 1000 km2 CW were converted into high forests after World War II. Nevertheless, many CW were maintained as stored coppices, which could be the last remainders of ancient coppice woods (ACW) in the Czech Republic. Knowledge of area and distribution of stored coppices is currently missing in the Czech Republic, because they are recorded as high forests in forest management plans. Many stored forests are currently approaching the maturity age, with a high risk that these last ACW remainders will be lost; therefore, an inventory of ancient coppice woods is necessary. In our study, we develop an index of likelihood of coppice occurrence (COP) based on the distribution of habitats favourable for coppices, as well as on past and current occurrence of CW in the Czech Republic from historical maps. COP index values were then used to generate a map showing the relative likelihoods of occurrence of ACW, which can serve as a baseline to support the compilation of an ACW inventory and their mapping in the field. Our results can help prioritize forest areas to be inventoried based on their higher probabilities of ACW occurrence.O

    Non-Intrusive Bedload Granulometry Using Automated Image Analysis

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    This paper presents a proprietary open source code for analysis of granulometric properties of bed load material based on non-intrusive automated image analysis. Vertical bedsurface images are processed using the proposed tool and verified with results obtained by well tested optical granulometry tool Basegrain. The practical application of the proposed tool yields accuracy comparable that of the tested framework and traditional sampling methods. Additionally, results showed that the average D50 grain-size sampled from riverbed of studied river section of river Danube agrees up to 95% with the average D50 sampled from riverbanks

    The Impact of Hydropeaking on Sediment Transport

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    Variable renewable energy sources, e.g. solar and wind power, require flexible management of energy sources to stabilize the power grid. Immediate changes in power generation and power usage is compensated for by the operation of hydropower plants. This subsequently leads to frequent flow fluctuations – hydropeaking downstream of the hydropower plant. This study examines the short-term impacts of hydropeaking of hydropower plants on the sediment transport using numerical morpho-dynamic model. The model is calibrated to field measurements and subjected to various hydropeaking scenarios on daily to sub-daily scale. Based on this study, the effect of hydropeaking of hydropower plant 23.42 km upstream of the studied river section would have negligible effect on the bedload transport in the studied cross section

    Ancient coppice woodlands - methodology of inventory, evidence and management

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    Methodology is focused on suggestion how to do an inventory, evidence and management of ancient coppice woodlands. Ancient coppice woodlands are defined as longterm and continuously coppiced forest stands

    The Forbidden Fruit of Federalism: Evidence from Romania and Slovakia

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    Territorial autonomy is one aspect of power-sharing in multi-ethnic societies. Nevertheless, the multi-ethnic countries of Central and Eastern Europe are still among the most centralised in the European Union. This article analyses the failure of any attempts to establish (symmetric) federalism or (asymmetric) autonomy, creating self-governed regions by the Hungarian minorities in Romania and Slovakia. The analysis focuses on the positions of the main parties of the ethnic majorities and the Hungarian minority parties in the two countries. In both cases, the parties representing the Hungarian minorities have favoured territorial autonomy along ethnic lines, but this demand has been rejected by the parties of the ethnic majority. Against the historical legacy of unstable borders, the parties of the ethnic majority argue that territorial autonomy or federalisation might be a first step for a revisionist agenda and separatism. Instead, supported by the European integration, the parties have been able to agree on decentralisation as a half-hearted compromise
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