Background The main causes of eutrophication of water bodies are discharges of polluting substances, mainly nutrients: nitrogen and phosphorus, from both point sources (e.g. sewage treatment plants) and diffuse sources. The diffuse sources of pollution are nowadays estimated to account for 50% of the runoff of nutrient compounds from the territory of Poland; hence, reduction in the point sources of pollution, however indispensable and significant, does not suffice. One of the tools to protect water ecosystems from diffuse pollution is to make use of the potential of ecotones (transitional areas between two ecosystems). Objectives The project’s main objective is to set up a number of activities for reducing diffuse pollution in the Pilica river basin in central Poland, by means of cost-effective ecohydrological methods that will help achieve the good ecological status of water in the Sulejowski reservoir – a large reservoir built in the 1960s to supply a fresh drinking water to the cities of Łodz and Tomaszów Mazowiecki. Another aim is to prepare a manual for optimum ecotone formation, with special focus on the effectiveness of diffuse pollution removal and enhancement of biodiversity. In order to improve the water quality of the reservoir, ecotones will be constructed using vegetation derived from the surrounding habitats in the region. An innovative aspect is the use of so-called “de-nitrification walls” that act as a barrier to protect against the inflow of nitrates from agricultural drainage areas, and also from areas without sewer systems. The beneficiary also plans to create a pilot site to demonstrate the possibilities of introducing the proposed measures in other areas.