Modelling of overflow emissions in Flanders

Ideally, for emission calculations long term hydrodynamic simulations shoul d be performed,but this requires long calculation times. Simplifications ar e consequently necessary. Due to the non-linear behaviour of sewer systems, hydrodynamic simulations using single storm events often will not lead to a good probability estimation of the overflow emissions. Simplified models using long time simulations give better results if they are well calibrated . To increase the accuracy hydrodynamic simulations with short time series can be used. The short time series are selected from the long time historic al rainfall series using a simplified model. To test the accuracy of these three methods, hydrodynamic long term simulations were performed for severa l (small) sewer systems with different characteristics to compare with. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.