488 1 Contemporary world is facing the fact that there is a discrepancy between different needs for drinking water and available resources of relatively clean water. There is a tendency for the proportion between the needs for and the availability of clean water to be vio lated under the influence of a rising number of popu lations as well as a greater contamination of water sys tems. Therefore, it is necessary to maintain the state of reservoirs, both natural and artificial ones, at a satis factory level. As lakes are evolutionary, natural and contemporary hydrographic objects, the research, especially if related to the living world and ecological relations, has to be constant, systematic, versatile and purposeful. Lake ecosystems are very susceptible to various influences, which is caused by a small degree of self regulation, wherefore the preventive lake pro tection is better than remediation of the harmful effects [13].The application of information technologies is very significant in managing lakes and reservoirs. Informa tion technologies enable merging all the relevant facts needed for managing as well as for showing them in the form best suitable for the user. For example, the unique information system of European lakes where 1 The article is published in the original. the data are organised within a relational database in five basic tables: station information, chemistry sam ple information, biology sample information, chemis try values (including variables such as pH or phospho rus) and biological values (such as biomass or abun dance per taxon) [22]. A special attention is given to the systems dealing with water quality. For example, information system for determining IBI (The Index of Biotic Integrity) for fish communities based on a greater number of input parameters [31], information system for managing water resources by integrating hydro chemical, hydrological, data about microbiol ogy, phytoplankton, zooplankton, macrophytes etc.[15], information system based on relational database containing a fuzzy models for water quality determin ing [19,20,21], real time information and control sys tem for decision support [11], etc.The objective of the information system (IS) SeLaR is creating an integral and purposeful informa tion system about lakes and reservoirs in Serbia. It should enable gathering in one place all the available data concerning lakes and reservoirs in Serbia, a rela tively easy access to scientific data and manipulation, a new, modern and contemporary insight into the state of lakes and hydroreservoirs in Serbia, as well as an Abstract-Information technologies provide a significant support in the management of lakes and reservoirs. Existing information systems mostly did not comprise all the necessary data and enabled collecting only a limited set of reports. More complex data analyses such as statistical analyses and data research were con ducted in separate environments and recquired additional preparation of the data. Information system of lakes and reservoirs in Serbia (SeLaR) was ...