Background The Bistrita catchment basin is highly sensitive to human activities, and is one of the most polluted basins of the Danube Basin. A Romanian Waters Annual Report on water quality revealed a high concentration of ammonium, nitrates, and organic matter, with high levels of nutrients mainly around two areas –Bacau County – one of the most industrialised regions during the Communist period - and the eastern city of Piatra Neamt. The overall anthropic pressure has led to a decrease in drinking water resources. The last two kilometres downstream of the River Bistrita are completely degraded. Objectives The aim of the project was to develop an integrated information system for water management capable of covering an area the size of the Bistrita river basin. This water management system would help to preserve and enhance the water quality while also promoting the sustainable use of the water resources. More specifically, the project aimed to adapt and combine a number of surveying tools in order to effectively monitor the sources of pollution in one of the most highly polluted river basins in Romania, the Bestride River Basin. These tools would then be able to predict the response of the Bestride River Basin ecosystem to modifications in the structure and intensity of anthropic pressures. The project also aimed to create a system that would reduce uncertainties related to basin management decisions and enable the authority to inform water-users about intended management measures and their environmental and economical advantages. In this way it would allow the users to be involved in basin management plans in advance of the adoption of final decisions. This system would include the following components: a) the observation and measurement of the quality of river waters and aquifers, in line with the Water Framework Directive b) the creation of an Open-GIS system integrating the available database, model outputs and water prices c) the development of a water quality models to analyse pollution in the surface water and groundwater d) the drafting of environmental and economic impact scenarios, including management measures e) the dissemination of project outputs and experience. Results In terms of the measurement work, the project managed to establish the location of the pollutant discharges near Bacau city using GPS technology. The project was also able to locate "observation wells", "exploitation wells", and "monitoring wells" using a combination of GPS and piezometric (pressure) level measurements. The project also used GPS to vertically position the cross-section and hydrometric surveys. As for the monitoring work, "in situ" measurements for improving and updating the existing database were performed. Several parameters such as plankton biomass, ammonium and nitrate concentration in the surface water were carried out by portable multi-sensors in addition to a series of laboratory analyses. Laboratory analysis was also performed to establish the silica concentration in the surface water. Emissions monitoring was carried out by sensor stations placed alongside the sites of major pollution ejections. This completed the existing databases in real time in areas where the spatial data coverage or quality did not fulfil the objectives of the pollution models. The project developed three mathematical models: a) Riverstrahler - this surface water model is one of the few available approaches for modelling nutrient cycling and ecological functioning in river catchments. The model consists in coupling a hydrological model (Hydrostrahler) with an ecological model (Rive). The outputs include the seasonal and geographical variations of the main water variables: discharge, oxygen, phytoplankton biomass, nitrates, ammonium, total phosphorus, and suspended matter. b) Modcou, which coupled a hydrological model with meteorological conditions to analyse, over a ten-day period, the piezometric variations and discharges in both surface and groundwaters. c) Newsam, which predicted nitrate circulation and evolution as a result of nitrate pollution of surface and groundwaters. The project then modelled regional surface water using the Riverstrahler model and regional groundwaters using the Modcou - Newsam models The DIMINISH online GIS system was developed employing a distributed architecture. All the partners and end users can access the system using a common web browser, such as Internet Explorer or Mozilla Firefox, to store, display, query, analyse and retrieve information. Users can adjust the model inputs and process spatial data for specific computations; integrate the multi-source processed information in decision-analysis matrices in order to better understand the impact of the pollution on humans and the environment; upgrade this result within a decision-analysis common-access space on the GIS Server; calculate the environmental costs and cost-effectiveness of different measures; and thus produce appropriate short- and long -term data to aid decision making. Reproduction of this system elsewhere in the country is possible, as many river basins in Romania are of similar size and face similar problems. Indeed, the GIS tools and mathematical models were subsequently used in two other LIFE projects in Romania (MOSYM and RIVERLIFE). The main dissemination tool is the internet, with three different websites: one for general presentation of the project, one for running the expert system and the last a forum for interactive discussions and feedback.