Author(s): Tamiarresan Ravichanthiran; Vivian Noo; Tien Ser Tan
Linked Author(s): Vivian Noo
Keywords: Modelling Sewer modelling Hydraulic modelling Database management Sewer planning GIS database
Abstract: The sewerage network in Singapore, comprising approximately 3,700 km of sewers, is managed by PUB, Singapore's National Water Agency. It is separate from the stormwater drainage system and collects the used water discharge from developments and conveys it to the water reclamation plants for treatment. To ensure that the sewerage network can handle the increase in discharge from future developments, sewer planners in PUB regularly check the utilisation rate of the network based on the projected increase in used water discharge in the future. With the advancement of technology and the increasing availability of IT tools, these sewer adequacy checks have evolved significantly over the past decade. Pre-2011, Excel and CAD software were used, with manual recording of sewer details and embedded formulae for capacity and flow calculations. This method was time-consuming and prone to human error. It also lacked the ability for planners to visualise the network comprehensively as a system or perform complex hydraulic analyses of the network. In 2013, migration of the work process onto a GIS platform allowed the flow, network, and development data to be consolidated into a single interface, resulting in a significant improvement in data management and spatial analysis capabilities. The GIS-based approach, while more efficient than the previous Excel-CAD method, still had limitations in accurately representing the complex hydraulic behaviours within the sewer network, because the sewer utilisation analysis was still based on the same formulae adopted previously under the Excel approach. From 2017, PUB embarked on a sewer modelling approach, developing a total of 42 sewer models for 7 sewer planning catchments. This approach enables planners to perform more realistic hydraulic assessments on the network, because complex hydraulic conditions, such as surcharges, backwater, flow translation, and attenuation effects in the network, would be accounted for. This paper aims to describe PUB's journey in innovating and improving the sewer planning process, highlighting how GIS databases and modelling tools work together to assist sewer planners in making informed decisions.
Year: 2025