Ukrainian Center of Environmental and Water Projects (UCEWP) is the Ukrainian company specializing in R&D, Consulting, and Software Development. Its team emerged in 1986 as a unit within Branch of Environmental System Analyses of the Institute of Mathematical Machines and Systems Problems (IMMSP) of National Academy of Science of Ukraine for the simulation of radionuclide transport in surface and subsurface water after the Chernobyl accident. Models and codes developed by UCEWP were successfully used for the development of Chernobyl Emergency Preparedness and Response System as well as for the development of several EU decision support systems for offsite nuclear emergency (RODOS, POSEIDON).