Modelling Seismic effects on a Sewer Network using Infoworks ICM

Objectives: The effects of earthquakes on a sewer network can be assessed using different well established methods such as flow monitoring, visual inspection, condition assessments and engineering survey. The main objective of this study is to investigate how hydraulic models were developed and used to assess the immediate devastating impacts of seismic activities on Christchurch’s sewer network. Methods: Infoworks ICM (Integrated Catchment Management) and InfoNet hydraulic modeling tools were used for this investigation. Two hydraulic models (2010 pre-quake model and 2011 post-quake model) were developed for Christchurch’s sewer network as part of this assessment. Findings: Hydraulic modelling was found to be a very powerful tool engineers can use to assess the impact of an earthquake and quantify the performance of sewer network. In Christchurch earthquakes caused significant damage to the waste water network. In post-earthquake Christchurch, there was an increase of 33% in the flows to the treatment plant due to earthquake related damage in the network. Application/Innovation: This paper summarizes hydraulic-model building and calibration works for pre-earthquake and post-earthquake Christchurch to evaluate the impacts of seismic activities on the sewer network. This paper suggests that any modern water authority could implement appropriate hydraulic modelling strategies and modelling tools to prepare for any unforeseen situation.