Testing performed by five glass cups has been a try to show form and extent of water reservoir soil base influence on its water quality. At the some time a possibility of alleviation of eutrophication by means of certain safety precautions have been examined. During the test performed on a model of parameters (water temperature, air temperature, O2, chlorophyll a, total nitrogen, etc) have been monitored. The results of actions reffer to a fact a soil base influences deterioration of water quality, especially immediately after water reservoir filling, but the mentioned negative influence of the soil base could be decreased applying certain safety precautions.

Mountain Goc is one of the regions with the highest water potential in Central Serbia (Yugoslavia), with specific annual runoff of 12-17 l/s per square km. Upper part of the catchment area of the Gvozdacka River has 111 springs, on the surface of 13.3 square km. 33 springs has volume yield from 0.5 to 2.5 l/s, with physical and chemical parameters of high water quality. These springs never dry up, even during years with low amount of precipitation. The upper part of the catchment area of the Gvozdacka River is under association Abieti-Fagetum, which is one of the worthiest in Serbia (Yugoslavia). Besides annual amount of precipitation, characteristics of soil, hydro-geological attributes of rock masses, influence of vegetation on processes of interception and evapotranspiration, which are very important factors for preservation of springs and their volume yield, also the system of forest ecosystems management. Not adequate measures in exploitation of forests lead to decreasing of volume yield of springs, and often to their disappearing.

5 water samples were taken from the irrigation channel nearby Kamendin, Sirig, Becej, Backo Gradiste, Backi Petrovac which is part of DTD (Danube-Tisza-Danube) system (Serbia, Yugoslavia). Content of Cd (cadmium), Pb (lead), Hg (mercury), As (arsenic), Cr (chromium), Ni (nickel), F (fluorine), Cu (copper), B (boron) in water samples was analyzed. The origin of these elements in the waters and the effect of potentional pollutant was analyzed. Also, deviation of content of these elements from permissible amounts which were announced in the Book of Regulation was commented.

The protected natural goods of the swamp Zasavica is situated in the north part of Macva (Serbia, Yugoslavia). It is parallel to the flow of the Sava river, which leads to the fact that it used to be the riverbed of the Sava and also of the Drina river. It is interesting for its variety of the plant and animal species. The investigations have been done during autumn period 1997, when the investigated groups were the most heterogeneous. It included algae, Rotatoria,Cladocera, Copepoda and Hydracarina. Among algae, Bacillariophyta were dominant. Among all the investigated groups Rotatoria were the most heterogenous, with great number of the species that are rarely present. Also, some Cladocera species were rare. The estimation of the water quality is given according to the bioindicator species.

Various physical, chemical and biological methods are used in complex investigations which are aimed at determining the quality of water. One of the oldest but also most widely accepted biological mathods is determination of saprobity on the basis of bioindicators. In application of these methods the existing lists of the indicators are most frequently used (Sladacek 1973, SEV 1977). In these lists only nine types of red algae (Rhodophyta) are specified as indicators of water quality. One of the main trends in development of algaeology in Serbia (Yugoslavia) is investigation of autoecological properties of algae and making a list of water quality indicator algae suited to the specific ecological conditions in water ecosystems of Serbia (Yugoslavia). The objective of this paper is to present information about apperance of red algae in the rivers of Serbia (Yugoslavia) and influence of physico-chemical factors upon their development, which represents a contribution to making of the above mentioned list of the water quality indicator algae.

The investigations of dynamics and composition of plankton, bottom fauna and fish community have been done at three localities (1-inflow, 2-the middle, 3-dam) at the Barje water reservoir (Serbia, Yugoslavia) during 1997. During winter period diatomea Asterionella formosa was dominant at all the localities. At the same time among zooplankton species Rotatoria group was dominant, with the emphasis of Polyalthra dolicoptera at the locality 2, while Keratella cochlearis was dominant at the localities 1 and 3. The present species are oligo- and betamezosaprobionts. Among the investigated bottom fauna species Oligochaeta and Chironomidae were present. The number of oligochaeta was between 1665-7878 ind./square m. By qualitative analyses the domination of Tubificidae family was present. It is known that the presence of this group of organisms and it's high number indicate the organic pollution of ecosystem. 30 individuals of the bighead, (Hypophthalmichthys nobilis) with the average weight of 5.6 kg was captured by net.

In this paper the short review of the results of calculation of the coincidence between the water level and quality parameters at the gauging station Cuprija-rail bridge (Serbia, Yugoslavia) is presented. The basic principles of the applied method and criteria for the estimation of the statistic significance of coincidence indicators are given. At the end of the analyses and comments of the obtained results, as well as the possibility for application of this methodology are given. The paper gives numerical quantities of the estimated indicators of statistical significance of the coincidence of water level and quality parameters of groundwater. Also, the graphical illustration, which shows the common exceeding probabilities of the water level and quality parameters, is presented.

Amplified and accelerated eutrophication process is a characteritic of a whole variety of small and medium-sized water-bodies, such as channel systems, microreservoirs, ponds, lakes and bank regions of many even bigger ecosystems. During the process, in relatively short period of time, the upper capacity limit of a certain biotop is far too exceeded, which leads to reduced ability of ecosystem's autopurification. As a consequence of such degradation, ecosystem faces a serious discrepancy between members of a biocenosis e.g. in ration producers/consumers/decomposers, which, in the end, causes destruction, e.g. dystrophy of the hydroecosystem. The introduction of diverse fish communities, can, therefore, be one of the basic measures for enabling a sustainable trophic stability, in a sense of keeping a dynamic balance. This measure includes carefully planed fish community - it should consist of three basic components of a trophic food web (planktivore and macrophytovore, bentivore and carnivore). Apart from enabling certain biodiversity considering particular fish species (both quantitative and qualitative), care must be inevitably taken of age structure, as well as fish stock and fishing dynamic, concerning the number, quantity and age.

Results on sea - water quality control and level of pollution in the coastal Southern Adriatic (Montenegro, Yugoslavia) were discussed from data collected in 1997. Investigations from Boka Kotorska Bay, coastal sea up to Bojana river mouth and in front of Bojana river mouth were presented separately. For above mentioned areas, basic hydrographic parameters, as well as the level of bacterial contamination were examined throughout the year (1996/1997 period). In Kotor Bay, which is the shallowest and exposed to the strongest land - based sources, as in the Tivat Bay, some changes influenced by anthropogenic eutrophication were already found.

Using the then years data series of organic load (COD, BOD), ammonia and organic nitrogen, total phosphorus, detergents and oxygen dissolved, a heavy pollution of Bega Canal at the Romanian - Yugoslav Border ("Srpski Itebej" Control Station) is illustrated. High load of organic matters and nutrients as well as extremely low oxygen dissolved content created anaerobic conditions in aquatic environment, are the main characteristics of Bega Canal state at the analyzed location. As the Bega Canal (left tributary of Tisza river) is an international river, a transboundary issue of pollution is considered in this paper.