As flood the rising of the water level due to the tide ( tide ) is called. This period ranges from a low water until the next flood. On the coast, the term is often used Accruing water to distinguish it from inland flooding or flooding. The subsequent fall of sea level is called low tide ( going down water). The tide is not to be confused with the flood. Tide indicates a direction of movement during high water marks the highest level of the water.
Are the earth, sun and moon in a line, which is the case at the full moon and new moon, then add the forces acting on the earth tidal forces of the sun and moon. In this case, the tidal range (difference between the highest water level at high tide and lowest at low water ) falls from particularly high, spring tide ( spring tide / low tide Spring ) is called. If the sun is on the other hand at right angles to the moon (about seven days after the new moon or full moon), so there is called a particularly low tide, neap tide ( neap / Nippebbe ).
The flood current can reach into the tidal channels of the Wadden Sea substantial speeds (up to 20 km / h). Therefore, while hiking in the Wadden special care.
The height of the tide above the sea level is not the same everywhere. In the relatively cut off from the oceans Baltic Sea it is from 10 cm to the open North Sea usually at 100 cm. The tidal range of the Atlantic is in the area of the mid-Atlantic ridge at 50 cm. On coasts, bays and estuaries to where the water must narrow mountain pass, he is much higher. In the estuaries of the rivers, such as the Elbe and Weser, up to 4 m, achieved during storm surges up to 10 m. The tidal range is felt in rivers also in the interior, unless flood barriers exist and the difference in height is low ( Tidefluss ), eg Amazon, Thames, Elbe, Weser, Wümme, Ems. The tidal range on the English Channel is up to 12 m, on the Bay of Fundy from 15 to 21 m.
In floods, the water level is increased by the force of the wind beyond the industry standard. This water levels can be achieved, which are 3 to 5 feet above the normal mean high water ( MHW ). In the past, floods have required, in particular on the coasts of the North Sea considerable sacrifices, such as 1962 in Hamburg.
Often, the term also refers generally to flood a large amount of water flowing or colloquial to high water level.