Long-term monitoring of sediment accumulation in gully pots using thermal analysis

The sediment accumulation in urban drainage systems can reduce their hydraulic capacity. The installation of sediment monitoring equipment is very limited due to economic and technical factors, such as the high price of existing solutions or the low coverage of these systems for data transfer. This study presents the long-term monitoring of sediment accumulation in six gully pots using temperature- based devices across two urban catchments in Zurich (Switzerland). The monitoring campaign aimed to evaluate the performance of MONTSE devices under real-world conditions, considering seasonal temperature variations. Results showed high accuracy in sediment depth estimations, with mean errors of less than 20 mm compared to in-situ measurements, as well as maximum accumulation rates ranging from 9 to 35 mm/day. Therefore, continuous monitoring combined with prior experiences on sediment accumulation is proposed as an optimal strategy to ensure the optimal operation of urban drainage systems.