Evaluation of design criterias for storm water and combined sewer systems, flooding of storm water and combined sewer systems

The guidelines concerning design of Storm Water and Sewer Systems (SFT, TA-550) which is in common use in Norway, is outdated (from 1979). There has been implemented a new CEN-standard concerning these matters, directly transformed into Norwegian (NS-EN 752-2 and 4). A project dealing with how to analyse and design Storm Water and Combined Sewer Systems in the future is under accomplishment. The project : Calculations on how input of different model rain events, measured single rain events and longer time series of measured rain affect Storm Water calculations. Calculations have been carried out using the MOUSE model. More calculations are to be accomplished in the months to come. The results will be evaluated. Results so far show that this is of great importance. Analyses of measured rain data from two different rain gauge stations in Norway are carried out (Blindern and Karmøy). The analyses include frequency analysis on different rainfall durations. These stations have more than 30 years of measurements each. How the so called Intensity-Duration-Frequency curves (IDF-curves) are constructed today, and recommendations on how they should be constructed in the future is studied within the project.