This report describes the development of an outfall structure in Panama City. At this location a Matasnillo river enters the bay along the Cinta Costera. Since this river is polluted it causes a bad water environment and smell at the river mouth area such that it is unable for recreation. Boskalis wants to improve the area in co-operation with local authorities. To do so a solution had to be found for the problems caused by the river, while the peak river discharge during rainstorms will not cause flooding in the area. Several concept designs were developed and in the end a hybrid design, consisting out of an outfall pipeline and culvert, was selected as most viable solution. This design discharges the polluted water through the outfall pipelines several kilometers offshore. During rainstorm events the surplus in river discharge is discharged through the culvert structure. The design is substantiated by functional and structural design calculations. In the end a cost analysis was made.