Evaluating Seismic Effects on a Water Supply Network and Quantifying Post-Earthquake Recovery

Author

Christchurch City Council, Asset Management & Planning, Christchurch City Council, Christchurch, New Zealand

Abstract

This paper summarises the impact of major earthquakes, 2010–2011, on Christchurch’s water supply network and what recovery measures have been applied, what worked well, what did not and why. A number of issues related to the open nature of the Christchurch water supply network were identified during earthquakes. It was difficult to manage large water supply pressure zones during the post-earthquake emergency response due to multiple failures of assets. The performance of the post-earthquake, post-rebuild 2017 water supply network was compared with the pre-earthquake water supply network to investigate the success of the post-earthquake rebuild programme. A multi-million dollar repair and rebuild works helped to return the level of service of the network to the pre-earthquake level and the water leakage of the 2017 water supply network was found similar to the pre-earthquake level. Hydraulic model was used for immediate earthquake emergency response, what/if scenarios investigations and earthquake damage assessments. Hydraulic models were built for pre and post-earthquake water network of Christchurch. The performance of pre and post-earthquake hydraulic models were compared and the results are also reported in this paper. Hydraulic modelling was found to be a very powerful tool engineers can use to assess the impact of an earthquake on a water supply network and formulate alternative plans during emergency response. 

Keywords