Interrogation, water duck, trough bridge

A daggering or according to DIN 4047-5 (5.7) a piping is a pipeline in which a flowing water is passed under surface obstacles, usually with free water level. In the case of a longer stretch of water, the construction of which was subject to a planning approval procedure or an extension permit according to §31 WHG. A water duck is DIN 4047-5 (5.4) a junction structure in which a water is passed under pressure under a water, an incision of terrain or a low-lying obstacle. With a trough bridge, another water is crossed. These structures play a role in the water development planning, the inventory for the water framework line, as well as for the processing of flood hazard maps.