Free-Floating, Screening Level Visual Inspection of Large Sewers in Los Angeles, CA

Inspection of sewer pipelines on a periodic basis is a necessity for successful operation of collection systems. Operational and structural assessment is required to identify and remedy issues prior to failure occurrence. Beginning in 2017, the City of Los Angeles, Bureau of Sanitation (LA Sanitation and Environment, or LASAN), embarked on a program to systematically inspect and assess the condition of one its oldest, and critically important conveyances, the North Outfall Sewer (NOS) system. Much of its length was inspected using Closed-Circuit Television (CCTV), Light Detection and Ranging (LiDAR), and sonar profiling [combination known as Multi-Sensor Inspection (MSI)]. The cost of MSI inspections limited the length that could be inspected with available funds. LASAN sought a lesser cost option to perform screening level inspections rather than detailed MSI. This paper focuses on the identification and use of a novel untethered, free-floating platform for screening level visual inspections of large sewers.