Water and Wastewater companies operating all around the world have faced rising asset management and replacement costs, often to levels that are financially unsustainable. Management of investment needs, while meeting regulatory and other goals, has required: A better understanding of what customers demand from the services they pay for, and the extent to which they are willing to pay for improvements or be compensated for a reduction in performance Development of models to predict asset failure and to identify and concentrate investment on critical assets Improved management systems Improved accounting for costs and benefits and their incorporation within an appropriate cost-benefit framework Incorporation of risk management techniques Utilisation of advanced maintenance techniques including new rehabilitation failure detection technologies Enhancements in pipeline materials, technologies and laying techniques. These papers developed from LESAM 2007 for inclusion in Strategic Asset Management of Water Supply and Wastewater Infrastructures are focused on the techniques, technologies and management approaches aiming at optimising the investment in infrastructure while achieving demanded customer service standards, and they provide an opportunity to gain access to the latest discussion and developments at the leading-edge in this field. This book will be essential reading for utility operators and managers, regulators and consultants.

The papers in this volume of the IWA Publishing "Water and Environmental Management Series" (WEMS) 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; calibration of models; bed-load transport; sewer pipe roughness; advection in sewers; anoxic processes; infiltration and exfiltration; runoff source control; pollutant loads; ventilation and oxygen uptake. From the 37 full papers presented at the two workshops, 16 papers have been selected by independent reviewers from the SS&PWG for publication in this volume. They reflect rather well the variety of topics presented during both workshops, and bring the high-quality work of these junior authors to the wider audience it merits.