On 27-30th September 2021 at the Water Centre of the Warsaw University of Life Sciences, a meeting of the participants of the project ‘Optimal strategies to retain and re-use water and nutrients in small agricultural catchments across different soil – climatic regions in Europe – OPTAIN’ was held under the Horizon 2020 programme. 40 participants from Poland and abroad took part in the meeting. The sanitary rigor was maintained in accordance with the national regulations and internal regulations of the Warsaw University of Life Sciences (SGGW).