From all engineering disciplines, Environmental Engineering is probably the one which has to deal with the largest uncertainty in its models and data; in addition, it is frequently subject to limited data and scarce information. To date this profession has only very few instruments to systematically deal with these challenges. Our Department tries to fill this gap. Today’s research focus is: • Identify uncertainty, variability and risk, and characterize their effect concerning design and operation of water infrastructure systems in the built environment • Develop methods to quantify the uncertainty in the interpretation of experiments and in the development of models • Develop methods for the calibration and validation of flow models for technical reactors which do not perform according to expectation This theme covers all aspects of the interrelationship between engineering and the natural environment. It is thus arguably the broadest, necessitating much collaboration across disciplines. The CWEE has considerable expertise in Water Engineering & Environment, through its successful and long running. With the recent appointment of new staff, the water and environmental expertise has been strengthened further and new areas of research have been developed, particularly those associated with treatment processes and Environmental Engineering. There are, in addition, several other staff within the University whose research interests cover the field of environmental management and engineering.