Fairway Maintenance of the river Ijssel The inland trade is a very important economical activity in The Netherland. Therefore to maintain and improve waterways is a common activity. The main problems that threaten the safety in the shipping are the erosion and sedimentation on the banks, especially in the bend banks. So some studies are necessary to know the best method to avoid the sedimentation and erosion in these places. This study is focused in the effect of a sand trap in the River IJssel over the sedimentation and to try to answer questions about its effectiveness and if it is possible to find a better layout for the sand trap. To carry out this research is necessary to set-up a mathematical model which can reproduce the behaviors of the river and the sand trap. So a mathematical model has been built using the Delft3D software. So, the effectiveness of the original sand trap has been studied and three possible alternatives have been studied too. The alternatives are: - Two different sand traps with same volume of the original one, but shallower, longer than the original one and nearest to the sedimentation zone (alternatives A.1 and A.2). - Sand trap with more volume than the original one and nearest to the sedimentation zone ( alternative B). The results of this study show that the effect of the sand trap over the sedimentation in a bend located 2 km downstream of the sand trap is non-existent. Also the results show that the alternatives A.1, A.2 and A.3 are more efficient, it means that they catches more sediments, but they dont produce any effect over the sedimentation zone. To study the effect of a bigger sand trap and nearer to the sedimentation zone is necessary. Also it is recommended to improve the data about sediment transport, bed levels and discharges in the lower stretch of IJssel. These data will be necessary to carry out a better mathematical model.