The model MACH3 calculates the water-level. In conjunction with the actual wind forcing and dependent on the certain coast formation, possibly occuring storm surges can be predicted for the short term. The assessment of safety precautions for storm surges - like the determination of the building specifications of dykes and weirs - are of great importance. Scenario-calculations with MACH3 can be used to test whether or not existing or planned safety precautions are sufficient for the storm surges expected. Thus, MACH3 yields the decisive basis for measures regarding coastal protection. Also, the effects of any planned deepening of tidal rivers can be calculated. The calculations with MACH3 turn out whether or not the maximum tidal elevation will increase and which construction measures will be needed by this fact. These calculations yield the basis for efficient cost-benefit analysis with respect to the expected subsequent costs. With the help of MACH3, the spreading of hazardous substances can be determined, which have been released by ship accidents. Dependent on the actual meteorological conditions, the respective endangered coastal areas can be determined, and the respective measures can be taken.