The papers in this volume were originally presented at the 18th European Junior Scientists Workshop (EJSW), Portugal, on 8-11 November 2003 and at the 1st Asian Junior Scientists Workshop (AJSW), Malaysia, on 7-10 February 2004. The workshops were organised by the SS&PWG (Sewer Systems and Processes Working Group) of the IWA/IAHR Joint Committee on Urban Drainage. The two separate workshops were convened under the general themes of "Sewer Processes, Networks and Urban Drainage" and specific topics covered included integrated modelling of urban water systems; modelling of pollutant loads;...