Dr.Mairanowski is the recognized expert in the field of water resources management more than 35 years researches water objects, forecasting and modeling of water`s quality. For a long time he was an employee of the Ministry of a water management (nowadays Federal Agency for Water Resources of the Ministry of Natural Resources and Environmental Protection of the Russian Federation). Dr.Mairanowski participated more than in 70 large projects on protection of water objects in Russia, Eastern Europe and Asia. As the participant and the head of expert groups of the State Planning Committee of the USSR Dr.Mairanowski participated in consideration more than 50 projects which connected with rational use of the water environment. The head and the scientific consultant of 14 successfully protected master’s dissertations. The forecasting methods developed by Dr.Mairanowski widely were used in practice of design.