Building a resilient Wellington water supply - the formal opening of the Omāroro reservoir

The 35 million-litre Omāroro reservoir in Wellington has formally opened this week in a bid to make the Wellington water supply more resilient to potential interruption and disaster.

Wellington Water has led the development of the Omāroro reservoir, on behalf of Wellington City Council, to double the drinking water storage capacity of Wellington CBD and Eastern suburbs. This reservoir is situated within the inner Town Belt, and supplies water to approximately 70,000 residents including the regional hospital and other important community, commercial and industrial facilities.

The reservoir holds approximately 48 hours of supply to the city (at normal usage rates). After an event such as an earthquake, the reservoir would hold up to three weeks’ supply at restricted usage rates.

About the project

The reservoir has been fully buried and landscaped to maintain the appearance of the sensitive Town Belt environment.

Beca provided project management, planning and engineering services to Wellington Water for the duration of the reservoir project. Working closely with our project partners and stakeholders, the team maintained regular communication throughout the construction period, supporting engagement with the local community and local authorities. 

• This project included the construction of new bulk pipelines within the local highway network to connect the reservoir to bulk water supply network.
• The structure was required to withstand a 1 in 5000-year earthquake without rupture and a 1 in 2500-year earthquake without loss of water.

Figure 1: First half roof pour.  

Figure 2: The reservoir prior to covering.
 

Figure 3: Reservoir inlet pipe prior to filling.