Investigate the condition of an asset

Monitoring the technical state of an urban drainage (UD) system is at the core of asset management, the deployment of visual inspection technology (either using direct visual access for inspection of applying photo and/or video cameras) was and has remained the main method of gathering information on the technical state. Despite some known fundamental shortcomings visual inspection is expected to remain the main source of information for inspection for the foreseeable future. This chapter discusses the virtues of visual inspection but also provides insight into other technologies that have been tried and/or deployed on a more limited scale but do offer access to more and more exact information when compared to the visual methods. Although not much experience is available, inspection techniques for nature-based solutions will be discussed as well.