Rain Rain Go Away, and Don't Come back Some Other Day: Rebuilding Earthquake Damaged Stormwater Infrastructure in Christchurch

The SCIRT alliance is responsible for the rebuild of Christchurch’s horizontal infrastructure following the 2010 and 2011 earthquakes. Its stormwater objective is “to return the Land Drainage network to a condition that will facilitate the provision of levels of service that were provided prior to the 4 September 2010 earthquake.” 

SCIRT’s rebuild approach has moved from an initial intervention point approach whereby all defects above a damage threshold were repaired, to a Level of Service approach. This requires SCIRT designers to understand pre- and post-earthquake drainage performance, and to evaluate how the network’s level of service can be improved through their designs. This paper examines the processes SCIRT employs.

Damage to stormwater assets is evaluated through information collated from various spatial databases, pipe condition assessments, and sources such as pre-earthquake asset records and observed post-earthquake flooding; with all this information stored in shared software systems. Based on local site conditions, design standards that are being continually improved and refined, and the underlying drive for best-value solutions, SCIRT designers are producing resilient solutions that return Christchurch's stormwater system to preearthquake levels of service. Where appropriate, this may include deferring non-critical repairs while, on the other hand, out-of-scope works may be incorporated.