An Earthquake and Recovery of a Stormwater System

The Canterbury Earthquakes in September 2010, February 2011 and June 2011, caused substantial damage to the infrastructure in the greater Christchurch region. Within the Waimakariri district, the urban areas of Kaiapoi, The Pines Beach and Kairaki, which are prone to liquefaction and lateral spread, suffered the most damage. The Council’s stormwater system was particularly affected by siltation of pipes and waterways, damage to pipes, pump stations and stormwater basins and land movement which has altered localised flooding in the area. The immediate response focused on identifying damage and undertaking temporary repairs to key infrastructure to provide a functioning system, albeit at a lower level of service.

This paper looks at subsequent recovery stage for stormwater, including the detailed condition assessment, development of a stormwater strategy for these areas and subsequent revision of the strategy based of the classification of large portions as red zones. The focus of this paper is on the Council’s approach and the key lessons learnt.