Risk-based prioritization of inspection and rehabilitation of large sewers.

Abstract

Built drainage systems are large linear infrastructures, mostly with considerable service lives. Their value is substantial, their function is vital, and some are heritage. The rehabilitation and maintenance are low despite their natural deterioration with time. Rehabilitation of older infrastructures is not a priority and often is reactive. Subsequently, an increase in sewer collapses leads to groundwater and soil contamination and the discharge of untreated wastewater into natural water bodies. In the contemporary urban conundrum, a significant part of the sewer network has exceeded its design life, especially in older towns and cities. Even if new conceptual approaches allow reducing sewers’ length and effective separation of wastewater from stormwater, the older sewers must have regular maintenance and rehabilitation to reduce associated risks as much as possible.