A manual was designed from the BWK project group 2.3 with the title "Immission ori-ented standards for sewer and storm water overflows" regarding to the EU water frame-work directive in 1999. This manual contains recommendations for assessing the impact of overflows based on a simple procedure. The following project aims the development of an detailed method with application of models.
The impact of overflow is temporally very limited and impulsive. Also the spatial scope is limited for single overflows, but the sum of overflows within a certain river part can cause serious effects. Those temporal and spatial special features has to be considered in defin-ing hydrological assessment criteria.
2002 there were two diploma thesis conducted within the project. The first thesis "The limited flow acceleration as an hydrological criteria for assessing the impact of overflows" (D. Casper) addressed dependencies and influencing factors by formulation of hydrologi-cal benchmark criteria. Within the second thesis "Determination and assessment of the impact of combined sewer overflows (CSO): experimental investigations in the river Drei-sam in the urban area of Freiburg" (M. Rieser) the qualitative and quantitative impact of CSO on the river was captured.
Additionally high resoluted discharge data of various catchments in Germany were ana-lysed for characterisation and assessing of the influence of overflows on flow regimes. For sensitivity analyses regarding to these criteria hydrological models were applied. Besides this investigations were conducted with regards to the influence of high resoluted rainfall input data on simulation results. For this as well rainfall radar data were used and com-pared with ground station data as method for an optimum correction of the radar data has been developed.

[University of Freiburg]  [Hydrology]

Date: April 2003 | Webmaster: