Hydrodynamics of pollutant dispersion in river have very connected to the result of river water quality monitoring. Thar it require to be done because till to date river water quality monitoring still be done by parsial that is by connecting results data of analysis of river water quality concentration with the long distance of river in the certain time observation and without including hydrodynamics element which can influence the dispersion of pollutant in river. And to drawing result of river water quality monitoring (not persial) needed mathematics model which in one of its methods is finite difference. As for one of finite difference method used in monitoring or river water quality observation that is two horizontal dimension ekplisit-Leap Frog finite difference method because this method will be able to give the illustration of dispersion of polutant in river (2 horizontal dimension) which hydrodynamics element have been included in it. Keywords: hydrodynamics, dispersion, pollutant. Niekr Karnaningroem, Nadjadji Anwar, Basuki Widodo, Wahyono Hadi, Ediyatno, Sri Wulandari, Farhan Nizam'iar, dan Aditya Maharani.E-mail: nieke@enviro.its.id.ac
