Zoran Nikić

Land use change for flood protection: A prospective study for the restoration of the river Jelašnica watershed

Serbia’s hilly-mountainous regions are extremely vulnerable to flooding as a consequence of their natural characteristics and human impacts. Land mismanagement influences the development of erosion processes, and causes soil degradation that significantly reduces the land’s capacity to infiltrate and retain rainwater. Inappropriate land use as well as development activities replace permeable with impervious surfaces in the watershed. This leads to more rapid runoff generation and the more frequent appearance of torrential floods and bed-load deposits on downstream sections. Environmental degradation creates economicsocial problems within local societies which is often followed by depopulation. Restoring watersheds to their optimal hydrologic state would reduce flood discharge and by increasing groundwater recharge would increase both low-flow and average discharges in springs and streams. Best management practices could be developed through the application of specific combinations of biotechnical, technical and administrative measures, and by using the concept of ″natural reservoirs″. The design of such practices is explored through a case study of the watershed of the river Jelasnica, southeastern Serbia. Realization of these planned restoration works should help decrease the annual yields of erosive material by 44.1% and the specific annual transport of sediment through hydrographic network by 43.6%. Representative value of the coefficient of erosion will be reduced from Z=0.555 to Z=0.379. The value of maximal discharge Qmax-AMCIII (1%)=54.17 m3•s-1, before restoration, is decreased to Qmax-AMCIII (1%)=41.22 m3•s-1 after restoration, indicating the improvement of hydrological conditions, as a direct consequence of land use changes. Administrative measures are applied through ″Plans for announcement of erosive regions and protection from torrential floods in the territory of Leskovac municipality″.

Land Degradation at the Stara Planina Ski Resort

The environmental impacts of ski resorts in the Balkan region are great and can lead to landscape degradation and loss of land functionality. In this study, we present an example of the negative effects of human activities at the Stara Planina ski resort in southeastern Serbia. The objective of this study is detailed analysis of the characteristics of environmental impacts at the Stara Planina. The management of the ski area and ski slope development caused severe degradation of topsoil and native vegetation. The morphological characteristics of the area, lithological properties of the exposed material and climate conditions resulted in various geomorphic impacts, including rills, deep gullies, solifluctions and debris from rock weathering. Significant changes in land usage altered hydrological conditions, resulting in more frequent torrential floods in the downstream sections of the Zubska River and increased the sediment yield. Environmental impacts were analyzed in the immediate and wider zones of the ski resort in accordance with the specific topography and visual exposure. The restoration and erosion control measures have stopped degradation processes and helped to rehabilitate the appearance and functions of the landscape. The results show the importance of considering lithological (the type and characteristics of minerals present) and hydrological (precipitation, water storage capacity of soil, runoff) factors under the conditions of significant changes in land usage. The results of this investigation can contribute to the improvement of planning processes and the implementation of development projects in ski areas.

Modelling the influence of hydrogeological parameters on low flow in hilly and mountainous regions of Serbia.

Abstract During dry weather periods of the year with long rainless intervals, streams slacken to what is generally termed “low flow”. This work presents an analysis of the influence of hydrogeology on low flows, using multiple linear regression, in natural medium and small streams in hilly and mountainous regions of Serbia. The study cases encompass 61 gauged catchments south of the rivers Sava and Danube. Characteristic relevant minimum mean 30-day flows of 80- or 95-percentile exceedence (Q 80%, Q 95%) are taken as dependent variables. Independent variables are the observable hydrogeological quantities: catchment area upstream of a gauging station; surface area of a hydrogeological soil category in a catchment; number of perennial springs of minimum flow higher than or equal to 1 L/s in a gauged catchment; number of perennial springs, each of minimum flow higher than or equal to 1 L/s, in a given hydrogeological soil category of the catchment; cumulative perennial spring flow of minimum single flow higher than or equal to 1 L/s in a catchment; and cumulative perennial spring flow of minimum single flow higher than or equal to 1 L/s in a hydrogeological soil category of a catchment. Through multiple linear regression between the characteristic relevant low flow and the hydrogeological elements, 16 models are developed and analysed, each based on a different combination of hydrogeological elements and characteristic low flow. The regional relationships developed for the minimum mean 30-day flows of 80- and 95-percentile exceedences are evaluated. The statistical tests of the representation quality of each multiple regression relationship show that the models justify the use of hydrogeological elements.

Uranium content in ground water in Stara Planina Triassic sediments

Uranium investigations in the Stara Planiana Triassic sediments were carried out for several decades. Some of these geological and hydrogeological results that are related to an established uranium deposit in the Dojkinci-Brlog-Jelovica-Ponor area are presented in this paper. Hydrogeological investigations were performed to investigate the chemical properties of ground water (e.g. anion-cation composition, microelement content, radioactive element content, pH value, Eh value). On the basis of these data a hydrogeological model was established for ground waters with increased uranium content.

Procedure for underground water calculation regime of pedunculata oak habitat in plain Srem.

The calculation of the influence of the underground water level on the habitat conditions of pedunculate oak in the lowland Ravni Srem is presented. The management method in these forests is greatly determined by moisture regime. Hydrogeological conditions are significant factors of moisture distribution in the soil during the vegetation period. In the river Sava alluvial deposits in Ravni Srem, the serried type of aquifer was formed, mostly of subartesian character, connected with river waters by hydraulic connection. The calculation of underground water regime was adapted to the conditions of two-layer porous environment in the river Sava alluvium, in order to define the oscillations of piezometric pressure in the lower aquifer and the level of underground waters in the upper, less porous layer.

Uranium minerals of Bukulja mountain controls on storage reservoir water

Headwaters of the Bukulja stream on southern slope of Bukulja Mountain were confined in 1976 by the Garasi Dam for water supply to Aranđelovac and nearby communities. Geological explorations from 1949 detected several uranium occurrences on Bukulja Mt. and later identified uranium mineral deposits. This work considers the trend of total beta-particles radioactivity in the Garasi storage reservoir for the period 1991-2004. Samples for radioactivity analyses were collected from three depth levels near the dam: directly below the lake surface, at the lake mid-depth and above the lake bottom. A highly plausible assumption is that the rising trend of total beta radioactivity in Garasi lake water is genetically associated with the geological nature of the terrain.

Changes in discharged water quality from abandoned uranium mines near Kalna

Various genetic types of uranium minerals (infiltrated, hydrothermal, etc.) have been found in the region of Stara Planina. Uranium minerals in granitic rocks that build up the area of Kalna in central Stara Planina are selected for their importance and the degree of exploration. The analyzed levels of the natural radioactive and trace elements in water and fluvial deposits from a general area of the closed mines are presented in this paper. Relatively wide ranges of the obtained uranium concentrations in ground and surface waters are explained in this work by the presence of various geochemical barriers and by the variations in the quantity and velocity of ground water flow over the year.

Natural attenuation of petroleum hydrocarbons—a study of biodegradation effects in groundwater (Vitanovac, Serbia)

The role of natural attenuation processes in groundwater contamination by petroleum hydrocarbons is of intense scientific and practical interest. This study provides insight into the biodegradation effects in groundwater at a site contaminated by kerosene (jet fuel) in 1993 (Vitanovac, Serbia). Total petroleum hydrocarbons (TPH), hydrochemical indicators (O2, NO3−, Mn, Fe, SO42−, HCO3−), δ13C of dissolved inorganic carbon (DIC), and other parameters were measured to demonstrate biodegradation effects in groundwater at the contaminated site. Due to different biodegradation mechanisms, the zone of the lowest concentrations of electron acceptors and the zone of the highest concentrations of metabolic products of biodegradation overlap. Based on the analysis of redox-sensitive compounds in groundwater samples, redox processes ranged from strictly anoxic (methanogenesis) to oxic (oxygen reduction) within a short distance. The dependence of groundwater redox conditions on the distance from the source of contamination was observed. δ13C values of DIC ranged from − 15.83 to − 2.75‰, and the most positive values correspond to the zone under anaerobic and methanogenic conditions. Overall, results obtained provide clear evidence on the effects of natural attenuation processes—the activity of biodegradation mechanisms in field conditions.

Assessment of contamination, environmental risk, and origin of heavy metals in soils surrounding industrial facilities in Vojvodina, Serbia

Content of potentially toxic elements was examined in soils from Srem (Vojvodina), to evaluate industrial facilities as pollution sources. Based on the distribution of the elements, the results of sequential extraction, enrichment factor (EF), ecological risk factor (Er), ecological risk index (RI), and statistical analysis, the current ecological status of the soils was determined. Elements in soils around the industrial facilities can be grouped into the five significant components derived by the principal component analysis (PCA), which explains 78.435% of the total variance. Al, Fe and Mg, and K and Mn are associated with two lithogenic components, respectively. Anthropogenic origin is identified for Hg and Cd. Mixed sources, geogenic and anthropogenic, are identified within two PCA components; one wich includes As, Pb, B, Zn, and the other: K and Cr, Ni and Cu. Cluster analysis (CA) corroborated the results obtained by PCA. The preliminary results revealed that the soils studied in a vicinity of industrial facilities in Srem have been exposed to different degrees of pollution. Among the characterized studied elements, Pb, Cd, Hg, Cu, Ni, and Cr are the main contaminants. Based on calculated EF, the studied soils show minor to severe enrichment with heavy metals. Ecological risk assessment results indicate that Cd and Hg carry the highest ecological risk level, and Zn and Cr the lowest.

Mineral Waters of Montenegro

Mineral water resources, and especially thermal water resources, are relatively sparse in Montenegro. This is a result of the specific geological makeup and complex tectonic relationships. However, due to insufficient insight into the origin of these water resources, particularly the hydrogeological conditions, as well as geochemical relationships, as surveys in this area have been relatively modest in terms of both extent and scope, no optimal results have been achieved that would enable the utilization of these water resources for useful purposes. Mineral and thermal waters are found in three hydrogeological zones of Montenegro: coastal, central and Inner Dinarides. Five types of mineral water are allocated on the basis of hydrochemical characteristics: Na–Cl; Ca–HCO3; Mg, Ca–HCO3 with CO2; Na, Ca–HCO3 with CO2 and Na–HCO3, Cl with CO2.