Impacts of the 14th November 2016 Kaikōura earthquake on three waters systems in Wellington, Marlborough and Kaikōura, New Zealand: Preliminary observations.

Abstract

This paper presents preliminary observations about the impact of the 2016 Kaikōura Earthquake on drinking water, stormwater, wastewater in Wellington, Marlborough, and Kaikōura. These areas experienced widespread and significant ground movement during the earthquake, with permanent ground deformation in some areas caused by liquefaction and lateral spreading. In Wellington, drinking water quality was temporarily affected by increased cloudiness, and significant water losses occurred due to damaged pipes at the port. The Seaview and Porirua wastewater treatment plants sustained damage due to internal waves within clarifier tanks. There was also an increase in water infiltration to the wastewater system. Most failures in urban Marlborough were similar to the 2010-2011 Canterbury Earthquake Sequence. However, some rural water tanks experienced different types of movement, which highlights the importance of flexible pipe connections. In Kaikōura, damage to reservoirs and pipes led to loss of water supply and compromised firefighting capability. Wastewater damage led to environmental contamination, and necessitated restrictions on greywater entry into the system to minimise flows. Damage to these systems meant tankered and bottled water were necessary along with boil water notices, chlorination of the system, and portaloos and chemical toilets. Stormwater infrastructure was also damaged, which threatened the underlying road materials. Good operational asset management practices helped improve system resilience. Having robust emergency management centres and accurate Geographic Information System data allowed effective response coordination. Minimal damage to the wider built environment facilitated system inspections.