Search

The streams belong among natural part of the urbanized landscape. It is generally accepted that this type of landscapes together with stream may be very difficult restored to original levels of historical or natural status. Past design and realization of the stream modifications did not take into account in a sufficient extent the ecological criteria. Due to the predominantly technocratic approaches to addressing these issues, the ecological balance has been disturbed; and the hydrological and morphological conditions of the river channel have been changed. By the levees construction, the biota migration was prevented, the biodiversity was reduced, water quality deteriorated as well. The realization of optimal restoration measures represents a tool for improvement of current state of the stream from both the architectural and ecological point of view. The article is focused on the evaluation of the present state of the restored the Dubová River in the reach km 3,379-5,270 flowing through the residential area of Piešťany city in Slovakia. The current state of ecological conditions after implementation of restoration measures were evaluated on base physio-chemical and microbiological parameters of water according to Governmental Decree no. 269/2010 Coll. that including the requirements for achieving 'good' status of all water bodies" in Slovakia. The ecological conditions from hydromorphological point of view were analysed for extremal discharge conditions (maximal and minimal discharges) with model HEC-RAS. On base of the analysis of the ecological conditions of the Dubová River we can conclude that the restoration measures have partially fulfilled the expectations mainly regarding to architectural point of view by increasing possibilities for better contact residents with the river. Partially has been improved the self-purification processes and ecological condition in the river. The key task for improving the ecological status of the river in the near future is elimination of organic load contained in effluents flowing into the river.rief description of the study and used methods. [ABSTRACT FROM AUTHOR]

The article is focused on impact assessment of various parameters and factors on water quality models outputs. The impact of roughness coefficient variation and changes in boundary conditions on changes of outputs generated by HEC-RAS was investigated. Simulation results have showed a various response rate of input parameters on outputs. The strong impact shows roughness coefficient setup. Changes in boundary condition have had less influence on outputs. Relatively strong impact shows the changes of initial state of pollution concentration. [ABSTRACT FROM AUTHOR]

Water quality modelling is currently very effective and important tool in context of the task to ensure the required quality of water resources, respectively, to achieve (maintain) good water status according the Water Framework Directive (2000/60/EC). Mathematical models of water quality are an important tool for integrated water management, planning and protection. Integral part of such models is the modelling of fundamental physical processes affecting water quality - advection and dispersion. This paper documents results of measurements of the dispersion coefficient within the scientific project APVV 0274-10. Measurements in this project have been performed in various surface water bodies in Slovakia - lowland streams with low turbulence (drainage, irrigation channels), as well as in mountain streams with a high degree of turbulence. Within the field experiments both longitudinal, so as the transverse dispersion coefficients were measured. [ABSTRACT FROM AUTHOR]

Greenery of cemeteries often creates a substantial part of public greenery in our towns but often doesn't subserve greenery functions. The older architectonical burial places where the greenery by reason of spatial limitation is diminished on tree-lined communications represent the most widespread cemetery type of Slovak towns. The greenery also often exists as solitaires in grave field and existence of woody plants at these conditions is affected by various negative factors. We assume these factors as the main reason of vitality decreasing and poor aesthetic standard of woody plants in burial places. The article is focused on evaluation of greenery in the eldest cemetery in Nitra town. There have been evaluated woody plants during 10 years. The highest abundance of genus Thuja is a significant factor of contemporary image of recent burial places. Their individual planting in grave field is a recent characteristic element impairing original composition, complicating the service and visitors orientation in grave field. The obtained data describes complex dendrological composition of surveyed cemeteries, species composition and dendrological value of woody plants. On base of evaluation results we have proposed the principles of framework methodology for greenery restoration in sepulchral places [ABSTRACT FROM AUTHOR]

The paper presents the study focused on analysis of the outputs obtained by numerical model HEC-RAS in relation to the longitudinal dispersion coefficient D for experimental reach of modified stream channel. The coefficient is used as one of the key input data of water quality models that create the scientific basis for water management decisions making. Different theoretical and empirical formulas have been proposed for D value determination and they have revealed that this coefficient is variable parameter that depends on hydraulic and morphometric characteristics of the stream reaches. The authors compare the results of several methods of coefficient D assessment, assuming experimental data obtained by tracer studies in the Mala Nitra River. The results of tracer study and computation outputs allow to outline the important aspects of longitudinal dispersion coefficient set up in process of the HEC-RAS model use. [ABSTRACT FROM AUTHOR]

Operational control of microirrigation, or more precisely the watering of the plants, represents setting of the size of a single irrigation dose and timing of application by one of the science-based methods, to cover the consumptive water deficit as soon as it is possible. Proper irrigation system ensures that plants achieve high production yields, applying relatively small amount of irrigation water at the right time. The main objective of the thesis was to compare the methods of managing the irrigation of the plants by means of measuring soil moisture, water saturate deficit of the plants and leaf surface reflection based on the principle of remote sensing, and propose an optimal method how to effectively and efficiently use the irrigation water to ensure optimum humidity condition of the plants. Research was conducted on maize (Zea mays L.) grown in experimental containers. We had stopped the irrigation of the plants on the principle of daily evapotranspiration at regular intervals and moved them into a dry environment, where they were exposed to stressful conditions. We studied the characteristics listed in the drought stressed plants and identified which one will be the fastest and the most apparent, and give us the correct information about the change of the moisture condition of the plants, or more precisely about the need for irrigation, well in advance before reaching the permanent changes. By measurement of the soil moisture, we evaluated the need for irrigation according to the soil hydrolimits reduced availability point, which represents the lower limit of the easily accessible soil water for the plants and defines an interval of available water capacity. By measurement of water saturate deficit we studied the ability of plants to regenerate during the night and the initial signs of leaves wilting in the evening. With the leaf surface reflections we proceeded the anticipated changes in value due to the reflex changes in humidity. From the results it possible to come to conclusion that the response to the water stress was quickly and accurately reflected in the observation of the water saturate deficit of the plants. Changes in water saturate deficit of the plants currently responded to a real need for water and real humidity condition in which the plant was located. [ABSTRACT FROM AUTHOR]

According to the Water Framework Directive by 2015 most of rivers and streams throughout Europe should reach "good ecological and chemical status". To preserve the processes and functions of riverine ecosystems the appropriate measures have to be applied also in field of hydromorphological status (HMS). On base of land-use structure analysis in catchments and survey results conducted at 20 sites in 100 sub-survey units we identified the key factors that affect the recent HMS of the streams in South West part of Slovakia. Performed statistical analysis showed the existence of strong and moderate relationship between the land use character in catchment and total HMS (0.484 < r < 0.682). High level of statistical dependence was found between total score of HMS and percentage of forest area in catchment with positive correlation of 0.68 (statistically significant with p < 0.005). The other land use categories are significantly negatively related to the hydromorphological status - agriculture r = 0.57 (p < 0.01) and urban areas r = 0.48 (p < 0.05). The obtained results provide a reason to reject our hypothesis that streams, which are under human pressure are able within the process of passive restoration achieve a good hydromorphological status. [ABSTRACT FROM AUTHOR]

Various EU Directives have set targets for the reduction in the amount of biodegradable waste sent to landfill and also stipulated that governments should draw up plans to prevent or reduce waste production and its harmfulness; recover waste by means of recycling, re-use or reclamation; use waste as a source of energy; ensure that waste is recovered or disposed of without endangering human health. According to the legislation of the Slovak Republic, since 2006 landfilling of biodegradable waste from gardens, greenery and public cemeteries is prohibited. Since 2013, the introduction of separate collection of biodegradable waste for all municipalities of the Slovak Republic is compulsory. Environmentally most appropriate means of biodegradable waste recovery are composting or anaerobic digestion, from which arises biogas. But there is not sufficiently built infrastructure for biodegradable waste recovery in the Slovak Republic. For the proposal of effective systems for separate collection and recovery facilities (capacity or logistically) is essential knowledge of representation biodegradable waste in municipal solid waste, and also its composition. To determine the biodegradable waste representation in municipal solid waste, we have chosen the analysis methodology according Kotoulova. Survey indicators of quantity measurement are made by direct measurement of the weight of the waste category in the representative sample. The analysis is being performed for each season. For two years, we have conducted eight quantitative analysis of residual municipal solid waste composition. We have considered the effect of the seasons on the weight of the biodegradable waste representation in rural area. We also compared our results with the analysis carried out in 2004 and 2005 in a similar rural area. [ABSTRACT FROM AUTHOR]

During the operation of the water reservoirs in common conditions there occur the processes of the siltation as the result of the erosion in the watershed and also the processes of sediment displacement within the reservoir or sediment escape out of the reservoir as the result of the inflowing water during the floods or higher water discharges during the spring snowmelt. These processes are forming the shape of the water reservoir and this process affects the depths of water and total amount of stored water. The changes of the topography of smaller water reservoirs are not monitored periodically or occasionally and the methodology for the measuring is not made. For the larger reservoirs there is used the method of periodical measuring of the reservoir profiles as the cross-sections of the reservoir bottom. The comparison of the identical profiles is then used for evaluation of the siltation processes and calculation of the water capacity and sediment quantity difference during the revised time period. The method works with the depth measuring (echo sounding, level staves, calibrated lead line) and measuring of the distance of depth measuring in profiles. The goal of this paper is to assess the new method of monitoring of the reservoir topography with non-contact system of sonar and GPS receiver, which measures and generates the field of points with known coordinates at the bottom. These points can be used in GIS software for the creation of the TIN model that represents the reservoir bottom shape. The assessment of this method is done as the assessment of the accuracy of the created TIN model as the comparison of the geodetically measured elevation of points and elevation of points extracted from TIN model. The method was tested at the swimming pool, where steady and mostly plain bottom can be measured with geodesy tool - GPS measuring and compared with the TIN model created from data collected with non-contact measurement with GPS and sonar during the sail with small vessel. The comparison of the modeled elevation and the real bottom elevation offers the evaluation of the accuracy of the method. The results lead to conclusion that modeled elevations (calculated from data of TIN model created from the non-contact measured input data) differs from the direct GPS measurement in approx. 20mm in plain parts and 70mm in sloped parts of the swimming pool bottom. [ABSTRACT FROM AUTHOR]