Irrigation water quality as indicator of sustainable rural development

The sustainable rural development more and more depends on the efficient usage of water resources. Most often, at least in one part of the year, the rain is not sufficient for plant growth and rain plant production significantly depends on the yearly precipitation variation. The increase and stability of the agricultural production is possible in the irrigation conditions. The most part (around 70%) of the global water resources is used for food production. Irrigation water quality indicator is used to show if the available water resources have the required quality for application in agriculture. Irrigation is characterised by the complex water-plant-soil relationship, and in that eco-system the man as the end user of the irrigated fields occupies a very important place. That explains the difficulties in producing one universal classification of irrigation water quality. The paper analyses numerous water quality classifications from the aspect of the applicability on the quantifying of this indicator. The adopted classification should possess understandable, qualified and internationally comparable indicator. Thus, local classifications (Neigebauer, Miljkovic) cannot be used for this indicator. United Nation Food and Agricultural Organization (FAO) and US Salinity Laboratory (USSL) classifications are used for the evaluation of the irrigation water quality throughout the world. FAO classification gives the complex picture of the usability of the irrigation water from the point of its influence on the soil and the plants. However, the scope of the analyses is not often suited to the needs of that classification, which makes it difficult to apply. The conclusion is that the USSL (US Salinity Laboratory) classification is best suited to this range of chemical water analyses. The evaluation of the irrigation water quality indicator in the Juzna Morava river basin, upstream from the Toplica river estuary is given in this paper. Based on the obtained results, it can be concluded that the irrigation isn’t limitation for sustainable rural development

The Nišava river water quality as the indicator of the sustainable development of the city of Niš

The Nišava river has a great importance for the sustainable development of the city of Niš. From the Mediana spring, which is on the bank of the Nišava, the city of Niš satisfies around 30% of its water demand. The aim of this paper is to, on the basis of the analysis of several tens of parameters of water quality; determine whether the Nišava river is a limiting factor to the sustainable development of the city of Niš. For this purpose the data of Public Utility Company Naissus have been used, as it collects daily samples of the Nišava river water. The number of conducted analyses, depending on the water quality parameters, varies from 1 to 1,240. The obtained results, which have been presented in detail in the paper, indicate that a great majority of analyses, of almost all the water quality parameters, is within predicted range. At the end of the paper, certain measures have been proposed, which should contribute to the sustainable development of Niš in this field.

BATHYMETRIC SURVEYS OF SHPILJE RESERVOIR

Periodic bathymetric surveys are carried out to define quantity of sedimented material in reservoirs, as well as to determine the areas most endangered by the silting process. Such surveys in the Republic of Macedonia were started as an obligatory and regular practice in the seventies of the last century, immediately after the formation of the larger artificial lakes. These were carried out for almost all reservoirs in the country and it can be said that there is already a sufficient amount of data on some of them that can serve as a basis for high quality analyses of the silting trend of the reservoirs and of the extent to which erosion is affecting the basin area. This paper provides a review of the results from the latest field surveys and analyses of changes in the configuration of the Shpilje reservoir bottom, carried out in the period 2014 to 2016

Application of Macrobiological Methods in the Settlement Wastewater Treatment

The approach to solving the problem of water protection is changing in the world, and the opinion that wastewater is a resource instead of waste is now prevalent with research being directed in the direction of simpler, energetically more rational and more economically acceptable technological solutions for wastewater treatment, primarily in the field of biotechnology, especially there where favorable climate conditions and the use of large land areas are available. The mechanism of wastewater treatment by macrobiological methods is simple and is reduced to extraction of certain substances from wastewater directly with plants or through the food chain with animals and their concentration into macrobiological living stations. Macrobiological living stations are extracted from the water in the form of biomass by simple mechanical methods, and in that way the final removal of nutrients and other substances from the water is completed. The produced biomass can be used as food or feed, with mandatory sanitary inspection, or as an emergent in biomass production. This paper presents the principles of application of macro biologic methods in wastewater treatment and the experience gained through the research at the Faculty of Civil Engineering of Niš and at the waste water treatment facilities in Sokobanja

ROCK RAMP IMPACT ON THE RIVERINE HYDRAULIC

The following case study is part of a wider research of the impact of rock ramps on river environment. It aims to give a quantitative assessment of the velocity reduction in upstream section of a rock ramp. The alteration of the flow velocities is one of the most considerable factors for the habitat modification. The creation of still water environment in upstream impoundment might affect the physical properties of the habitat. Thus a mutation of the hydrobionts diversity may occur. By means of one – dimensional numerical model а comparative analysis of velocity fields is executed. Two cases are examined: before and after construction of a rock ramp with step – pools. The model proofs a significant flow velocity reduction in upstream section, which might have a negative environmental impact.Another point of interests of the study is the high flow river capacity. The flooded areas and the water level variation are evaluated at Q50%, Q5% and Q1%. The results can be used for assessment of the structure reliability and for analysis of both: saturation of riparian zone and alteration of floodplain ecology

River Floodplain 1D/2D Hydraulic Modelling Combined with Recent LiDAR DTM Technology

The study presents problem of floods management for lowland rivers and provides solution for such complex task. The paper aims to elaborate a methodology for flood management model on large lowland rivers using precision digital terrain models (DTM) and combined 1D/2D unsteady flow model. The river Danube on the territory of Serbia was used with its tributaries for the development of the model. The length of the hydraulic model is 715 km and the achieved accuracy of the model, by comparing the calculated and observed levels on 10 water stations, is below 10 cm. Combined 1D/2D HEC-RAS model is adjusted by making use of the resulting high-resolution input. The ability of the combined 1D/2D model, based mainly on the high-accuracy input data, provides an accurate estimate of flood wave propagation. The result of this paper is a defined methodology providing sufficient accuracy to the hydraulic model of flood wave propagation in case of large lowland rivers, requiring acceptable short calculation time. Also, the methodology to specify relevant flood stage (design flood) which is used to determine levee crest elevation is developed in this paper

Influence of service quality on customer satisfaction in Serbian logistics practice

Starting from the findings of other authors that logistic service quality indeed affects customer satisfaction, the author of this paper wanted to examine whether this relation existed in the context of Serbian logistics practice. The research was conducted in October 2021 on a sample of 234 respondents who used the services of shipping companies from Serbia. Send questionnaires consisted of three general questions about demographic variables and sixteen closed-ended questions about the perceived service quality based on the dimensions of the SERVPERF model. The researchers assessed the correlation between variables by regression analysis. The results of the research confirm a significant positive correlation between the logistic service quality and customer satisfaction. Responsibility has been shown to have the greatest impact on customer satisfaction, while other characteristics of service quality - reliability and tangibles show a medium, and assurance and empathy almost insignificant positive correlation with customer satisfaction

LEVEL CROSSING RATE OF MACRODIVERSITY OUTPUT PROCESS IN THE PRESENCE OF η-μ SHORT TERM FADING AND GAMMA LONG TERM FADING

In this paper macrodiversity reception with macrodiversity selection combining (SC) receiver and two microdiversity MRC receivers operating over shadowed multipath fading channel is studied. Received signal experiences  short term fading and correlated Gamma long term fading resulting in system performance degradation. Level crossing rate (LCR) of η-μ random process and level crossing rate of signals at outputs of microdiversity MRC receivers are efficiently calculated. By using these derived formulas, level crossing rate of macrodiversity SC receiver output signal process is calculated. By using this result, average fade duration (AFD) of the proposed wireless communication system can be calculated. The influence of  η-μ  short term fading severity parameter, Gamma long term fading severity parameter and Gamma long term correlation coefficient on level crossing rate is analysed and studied

ПРОЈЕКАТ ПОСЛОВНЕ БАЗЕ ПОДАТАКА

The database is a set of integrated, interrelated data stored without unnecessary redundancy, and are used to describe a real system in which they are used. This is the most complex form of organization of data, which are mutually related data are stored and used with the aim of securing the common use of information in the functioning of information systems. The concept of the development organization of data in database has a long history which dates from the construction of the first system for automatic data processing. The database covered all of organized information, regardless of the manner of their display, and physically housed in one place to serve different applications