In the frame of the project Revitalization of the Big DTD Canal and preparation for introducing modern wastewater treatment plants for the towns and industry in the Backa region, an all-inclusive program has been prepared for monitoring quality and quantity of water in the Big Canal and pertaining lateral canals. The paper presents results obtained for contents of nutrients (N and P) that indicate a poor quality of the Canal water, especially in the segment from the triangle to the hydrological node Vrbas. In many cases, measured concentrations of nitrogen and phosphorus were several times higher than maximal tolerable levels, so that it is necessary to undertake urgent measures with the aim of preventing further degradation of the Canal water, and eventually its revitalization.

Aspiration to multipurpose use of built drainage systems structure in Vojvodina, total length about 20,000 km, must be followed by detailed investigation of influence of water stream through detailed canal network (DCN) from water source to the final consumer. Typical cases of two purpose use of DCN is supply canal of drainage / irrigation system on region Middle Banat, Zrenjanin, characterized by taking water from Begej river and long stream to the final consumer. Influence of long stream through DCN to water quality change are investigated on mentioned localities during 2004. Obtained results are pointed out water quality decrease in these conditions. Decrease is expressive in case of smaller flow. This paper deals with estimation of water suitability for irrigation taking into consideration possible undersirable effects of this water to irrigated soil.

The research of phytoplankton in water of Hydrosystem DTD in Banat region (canal complex and the rivers Zlatica, Old Begej) has been carried out seasonally i.e. in the spring, summer, autumn and winter of 2003 and 2004. According to guidance of Anon (2003) we selected biological element - phytoplankton in establishing referral body of water with maximum ecological potential (MEP) of the Danube-Tisza-Danube Hydrosystem also classified as artificial/heavily modified water. Classification was made according to Sorensen indices of similarity. Reference conditions with MEP were assigned to the HS DTD, canal Banatska Palanka - Novi Becej, Novi Becej - Melenci stretch. As determined by phytoplankton analyses, investigated canals and rivers could be classified as waters of good ecological potential, except the rivers Zlatica, Stari Begej (Old Begej) and some sections of the Canal Plovni Begej (Navigable Begej) what was designated to moderate ecological potential.

During several years of hydrobiological investigation of the Zapadna Morava river the Medjuvrsje and Stancici localities stood out; the most favourable water quality was registered with the Medjuvrsje reservoir (being constantly of the class 2), whilst, according to all the data obtained over the years, water quality of the Zapadna Morava at Stancici locality was the worts. The Medjuvrsje reservoir is in stable eutrophic phase. The saprobic index value points to a certain water quality improvement. Floristic diversity in the locality of Stancici increased over the years. An increase in the percental share of the oligosaprobity indicator indicates a certain organic load decrease and an improving water quality trend was recorded as indicated by lower saprobic index values.

Redudance rivers are basic hydrographic problem in area of Radjevina. Their appearance to associate for most rivers in the confluence of Likorda river and have character of season. Using method of quantity index the rivers of this region are classified in special hydrological classes. On the basis of this typology the possible models for solution of this problem are given.

Nitrogen and phosphorus contents in water, sediment and shoots of Phragmites communis Trin, and Typha latifolia L., as possible indicators of trophic state were used in the area of the Bardaca fish-pond. The results of total nitrogen and phosphorus contents during growing season indicate the hypertrophic state of waters in all locations.

Water samples for chemical and microbiological analyses as well as material of the water community to be considered in the assessment of qualitative and quantitative composition of phyto- and zooplankton, and bottom fauna were take on 30 May 2001 at two profiles. Judging by the most of the analyzed chemical parameters, with the exception of BOD5 and oxygen saturation values indicating class 2, water of the Bovan lake accumulation belongs to the 1st class of water quality. According to the presence of heterotrophic bacteria, water was characterized as class 1-2 (after Kohl). Also, 6 groups of phyto- and 4 groups of zooplankton were recorded. Relative abundance and qualitative composition values of plankton show that saprobic index ranged from 1.54 to 1.98 pointing out oligo-beta, namely beta-mesosaprobic character of the accumulation. Saprobic index when oligochaetes were considered amounted up to 3.6 (alfa-mesosaprobic water).

In this paper, there were discussed the results of ecological investigation of the Montenerin part of the Adriatic sea during the period 1996-2003. Evaluation of the sea-water quality was done in the coastal sea. The importance of multiannual ecological investigations was emphasized, too.

In this paper, we used similarity index, such as Sorensen similarity index (S), Jaccard similarity index (Cj) and Percentage Similarity Index (PSC), to show similarities and contrasts within the qualitative structure of zooplankton of various bays within Boka Kotorska. This kind of statistical overview was made for Boka Kotorska Bay for the first time, so we believe that it is a valuable contribution to recent studies on zooplankton. Tables show the results for each index individually, as well as the smallest and greatest similarity among the bays. We also presented the number of recorded species in the Boka Kotorska Bay arranged by months for three different years.

Problematics of humic substances removal from surface water with low mineralization and temperature near zero was presented. In this analysis very large spectar of solutions especially for this area was included. More detailed data obtained with this patent solution (7) in laboratory conditions on purificaton of raw water are presented in the analysis. Comparing the new technology with existing purification state and many unsuccessful attempts to obtain the standards gives the possibility of choosing the best drinking water treatment solution for plant on mountain Kopaonik. General estimation of different methods that can give necessary water purification level was done. Technoeconomic and ecological analysis of different water purification methods was realised and the a rational solution with high effects on protection of the environment was given.