10.4122/1.1000001299
Verworn, H.-R.
H.-R.
Verworn
Kraemer, S.
S.
Kraemer
Shi, L.
L.
Shi
Statistical classification of frequent rainfall events as a basis for operational aspects of sewer systems
DTU Library, Technical University of Denmark (DTU)
2005
Conference presentation
Urban drainage
rainfall statistics
University Of Hannover, Institute Of Water Resources Management
Institute Of Water Resources Management
University Of Hannover
2005
en
10.4122/1.1000001300
text/xml
Statistical analysis of rainfall and runoff are generally carried out for design and rehabilitation purposes. All processes generated by smaller events are of no interest in this context. While these design events have no relevance for the everyday performance of the drainage systems, statistical analysis of the more frequent events has to cover more aspects than just the maxi-mum intensities of certain durations. Operational aspects for sewer systems include e.g. sedi-mentation and remobilisation of settleable solids which depend mainly on turbity, velocity and bed shear stress. In this investigation the whole rainfall process has been analysed for the frequency of events with certain properties. In a first step a subdivision of the rainfall process into secluded rainfall events has been carried out. The effects of various lengths of time with no rain between the events are described. Then the maximum intensities for various durations are determined and analysed for their frequency resulting in frequency distributions. The re-sults are also related to the total number of events and to design rainfall values. The applica-tion of the results for operational purposes is demonstrated by an example. Assuming quasi-linear transformation from rainfall into runoff the findings on the rainfall side are transferred to the runoff side leading to frequency distributions for flow and velocity.