Fractionation of Infiltration and Inflow (I/I) components in urban sewer systems with regression analysis

The management of urban sewer systems requires data about variability and discharge of typical waste water sources in urban catchments. Especially the infiltration of groundwater and the inflow of surface water (I/I) are important for decisions about rehabilitation and operation of sewer networks. In this paper a new methodology is presented which supports the identification and quantification of I/I components. The methodology is based on a combination of model approaches representing the different flow fractions in sewer networks. Parameters of the models are deduced by the application of a multiple linear regression. The methodology was applied for the City of Dresden. Results of the fractionation method are presented and discussed.