This diploma thesis achieves the goal of designing a construction for dewatering river mud. By transporting smallest particles of sand in a river, sand banks are built. To keep those rivers, used for commercial shipping, passable, floating dredges dig the sand off the ground of the river to a second swimming platform. This pontoon is the place of the dewatering. First of all primary information about river mud and commercial shipping and then statements about most common dewatering treatments are collected. Explanations about functionality, guidelines for dimensioning and pros and cons of each method are marked out. For evaluating the best dewatering treatment an objective, technical assessment, according to VDI 2225 and a subjective written assessment are made. To compare the given information about dewatering to practical information, mud out of the Danube is analysed and conclusions about most efficient dewatering methods for the given river mud are found. Last the learned knowledge is turned into finding two designs best useable for dewatering constructions on a swimming pontoon. Each design implies machineries from different companies with a short description.