Planning Instruments for the Water balance in Settlement Areas

In water bodies dominated by settlements, disturbances of the water balance and hydrological dynamics are present, which are caused by land sealing and the discharge of precipitation runoff. They are the reason for the paradigm shift from the discharge to the retention principle in the planning of rainwater management in settlement areas. Their goal of minimizing the impact on the natural water balance is achieved through measures to evaporate, infiltrate, and delay stormwater runoff instead of the previous complete and rapid discharge. This article summarises the results of the BMBF (German Federal Ministry of Education and Research) joint research project “Water balance of settlement- affected bodies of water” (WaSiG), which make an essential contribution to the professional planning of rainwater management in keeping with the retention principle.