Design water level

A design or rating is made on the basis of measurements preferably taken over a longer time and/or of many occurrences. Important for the design/rating are the extreme values. Relevant for the design water level are the maximum values of the ground water table as well as the flood levels, in many places documented for centuries (even if it is as the kerf in the stone of a historical building). The measured maxima plus an additional security value add up to the rated value. The information about the design water level is provided by the municipal/urban building authorities; it is essential e.g. for the selection of the building ground, the determination of the drain systems, sealing measures/heights as well as safeguards against flotation.