The present report is concerned with an analysis regarding the capacity of the sewerage system along with the recipients Vestre Landgrøft and Østerå in the city of Kærby, in regard to climate proofing the city.
For academic reasons, the report is also comparing two types of surface runoff models. The result of the comparison has shown, that the more advanced surface model B gives a better description of the runoff volume, than the less complicated surface model A.
The analysis of the sewerage system in Kærby has shown, that there are a few challenges in order to meet the functional requirements, and at the same time reduce the discharge of wastewater to the recipients during heavy rainfall. In the report, several areas, that are in risk of flooding during heavy rainfall, has been pointed out. The capacity analysis of Vestre Landgrøft and Østerå shows, that there is small risk of flooding from Vestre Landgrøft. In order to investigate the future conditions for Kærby, a historic rain series has been extrapolated to the year 2100.
As a short term solution in order to reduce flooding of the city and discharge to the recipients, three firstflush basins and three infiltration basins has been dimensioned. For the long term solution, a new separate rainwater system has been dimensioned to meet the functional requirements now as well as in 2100. Furthermore, several climate proving precaution has been tested, such as lowering the streets, introducing pipe basins and expropriate plots, in order to reduce damage from flooding during heavy rainfall.