ABSTRACT
This chapter introduces the concept of sewerage risk management. It examines structural and hydraulic rehabilitation methods. Sewer rehabilitation is one of the main areas of activity of drainage engineers. This has been recognised for many years, and certainly since 1983, and the publication of the first edition of the Sewerage Rehabilitation Manual (SRM). Sewer rehabilitation can be accomplished by means of repair, renovation, or replacement. Repair is localised work to correct damage to the sewer fabric. The four primary elements of sewer system performance are: hydraulic, environmental, structural, and operations and maintenance. Assessment of hydraulic performance is likely to involve hydraulic modelling of the system. The aim is to help to identify problem areas within the system and to investigate the possible effects of physical improvements within the system. Renovation methods generally involve providing a new lining, inside the old, to a whole length of sewer.
