We’re building a new, larger water supply tank (reservoir) ensuring both current and future residents of Porirua have access to drinking water every day, including during a natural disaster. It will increase the amount of water available and stored from 4.5 million litres to 13.5 million litres, ensuring that Whitby and eastern Porirua residents can continue to access clean, drinking water if there is a disruption to the water supply network. 

Whilst the additional reservoir will help supply emergency water to both eastern Porirua and Whitby residents, it will also take pressure of the Porirua’s water supply network, benefiting all residents in the area. 

Construction is expected to take approximately two years and work is scheduled to start at the end of 2024. This will involve building the reservoir foundations and structure, around 3km of new bulk water supply pipes and a small building to house electrical and control equipment. Once the reservoir work has been completed, we will replant and landscape the area, as well as install a new stormwater management system around the reservoirs to ensure any rainfall post construction is filtered before it runs downstream.

The reservoir is around 41 metres in diameter (internal). It will help to store and supply an additional 9 million litres of water, significantly increasing the amount of water available to residents during a water supply disruption.

The reservoir will be made out of concrete and will be completely sealed. It has also been designed with the latest data on the area’s earthquake activity, making it more resilient and reliable in the event of a natural disaster. 

We’re in the process of procuring a contractor and but we will keep the community informed as decisions are made.

During construction, we will be using a couple of key stormwater management techniques to help filter and clean water before it runs downstream. The first way we can achieve this is by installing a site retention pond next to the active worksite. The fully fenced pond will have steep slopes, allowing runoff to flow into the pond. The dirt in the runoff will sink to the bottom of the pond, allowing cleaned water to flow out via a series pipes. The second way is by creating a shallow, but broad grass channel, known as a grass swale. They direct and slow stormwater across grass or similar ground cover and through the soil. This allows for any run off to be filtered before flowing downstream.

We will also install a new stormwater management system around the reservoirs to support good stormwater maintenance and ensure we continue to protect our taiao (environment)  at the end of construction.

On top of our investment in stormwater management, we have been working with the Kāinga Ora Sustainability team throughout the design process to help offset our carbon emissions where possible during construction. One of the ways we can achieve this, whilst protecting and enhancing the surrounding environment will be to replant three times the amount of native plants around the new reservoir and in nearby reserves. 

We will be working alongside future contractors to help support local community outcomes including creating employment and training opportunities where possible, supporting local businesses.