Welcome to our public open day on the proposed new water supply reservoir at Aotea, in Porirua - Wellington Water
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Haere mai Welcome to our public open day on the proposed new water supply reservoir at Aotea, in Porirua. Our experts are on hand to: • answer your questions about the proposal and its impacts • inform you about the planning application process. We welcome your queries and feedback. You will also be able to sign up for updates to keep informed as the proposal progresses. wellingtonwater.co.nz/work-in-your-area/porirua-reservoirs poriruareservoirs@wellingtonwater.co.nz
Why does Porirua need a new reservoir? Like the rest of the Wellington region, Porirua’s water supply network is vulnerable to seismic events. Porirua is vulnerable to extended water supply disruptions because: • it has no water sources of its own and relies on water from the Hutt Valley • the Ohariu Fault runs through the district, separating residents on the west side from the rest of the city. We are working together with the Porirua City Council to improve the resilience of Porirua’s water supply network to: • ensure that Porirua’s water needs can be adequately met in the case of a significant earthquake • reduce disruption on a day-to-day basis for network maintenance, repairs and upgrades • cater for Porirua’s future growth needs. To improve Porirua’s water supply resilience, we are proposing to build two new reservoirs, one to the east and one to the west side of the Ohariu Fault. wellingtonwater.co.nz/work-in-your-area/porirua-reservoirs poriruareservoirs@wellingtonwater.co.nz
Why have we chosen the Aotea site? We investigated seven possible sites for the proposed new reservoir to the east of the Ohariu Fault. Aotea was selected as the preferred site because: • it is at the right elevation • there are no significant ecological or cultural values associated with the site • there are already two reservoirs on site meaning much of the other infrastructure (e.g. pipework) is already in place • sufficient undeveloped land is available meaning buildings do not need to be demolished • it has good access for construction • there is sufficient space around the reservoir to allow landscaping to reduce its visual impact • it provides good value for money. wellingtonwater.co.nz/work-in-your-area/porirua-reservoirs poriruareservoirs@wellingtonwater.co.nz
The proposal
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wellingtonwater.co.nz/work-in-your-area/porirua-reservoirs
poriruareservoirs@wellingtonwater.co.nzSeismic resilience How will the reservoir perform in a major earthquake? The proposed new Aotea reservoir will be designed to withstand a significant earthquake and provide special post-disaster functions to the community. Essential parts of hospitals are designed to the same standard, which is about twice that for a normal commercial office building. Whilst it may suffer some damage and require repairs, it will not collapse or cause harm to people. Extremely low risk The risk to the community from structural failure is extremely low. In the unlikely event that the reservoir failed, the most likely effect would be cracking in the reservoir floor or walls which could result in a gradual loss of water. If there is a major pipe failure in the network fed by the reservoir, automatic valves at the reservoir will shut off the network’s supply. What about the two existing reservoirs at Aotea? The two existing reservoirs are not built to the same level of seismic resilience and in their current condition may not provide adequate drinking water supply after a large earthquake. It is intended to demolish the oldest reservoir built in 1956 (reservoir no.1) and to strengthen the second reservoir built in 1973 (reservoir no.2). wellingtonwater.co.nz/work-in-your-area/porirua-reservoirs poriruareservoirs@wellingtonwater.co.nz
Landscape and visual Reservoirs need to be located at a certain elevation to have enough pressure to distribute water across the network. This means they are often located on hilltops and ridgelines where they can be visually prominent features in the landscape. The two existing reservoirs are widely visible from many parts of Porirua. Planting around the new reservoir is proposed to reduce the visual impacts of the new structure. This has been designed to integrate with the planting being undertaken in the surrounding residential development. The two visual simulations below show how the site would look in 2033; without the reservoir (top image) and with the reservoir (bottom image). These images show the vegetation 10 years after planting. Over time the vegetation would grow further and screen the new reservoir more than shown in these images. Visual simulation without reservoir Visual simulation with reservoir wellingtonwater.co.nz/work-in-your-area/porirua-reservoirs poriruareservoirs@wellingtonwater.co.nz
Traffic
Construction of the reservoir would generate some additional traffic in the
area but this would be minimal and would not impact on road safety. The main
activities generating additional traffic during the project duration of up to 24
months would be:
Phase Activity Traffic generated (Approximate)
Total trips Average trips per day
1 Earthworks 600 – 1,100 15
2 Underfloor pipework detailed excavations 5 – 10 1
3 Incoming/outgoing pipelines 13 – 30 5
4 Outlet valve chamber and construction 10 – 15 5
5 Reservoir structure 300 – 400 10
6 Water test – –
7 Backfill 350 – 700 15
8 Landscaping 50 – 100 5
Workers travelling to and from site 15
Construction traffic will travel to and from the site via Queen Charlotte Drive, Frances Brown Avenue,
Okawai Road and Whitford Brown Avenue.
wellingtonwater.co.nz/work-in-your-area/porirua-reservoirs
poriruareservoirs@wellingtonwater.co.nzNoise The main sources of noise and vibration during construction will be from truck movements, heavy vehicles, and machinery. To reduce noise we would ensure: • careful truck route and loading point selection • maintenance of construction equipment • use alternatives to tonal reversing alarms and prohibit engine braking • noise barrier screens between the construction site and the nearest residential properties • road maintenance. • restrict construction activity to 7.30am to 6pm Monday – Saturday. wellingtonwater.co.nz/work-in-your-area/porirua-reservoirs poriruareservoirs@wellingtonwater.co.nz
Next steps
Provide your feedback
You are welcome to provide feedback on the proposal to poriruareservoirs@wellingtonwater.co.nz.
We will consider and respond to your feedback prior to lodging a notice or requirement (see below).
Lodge a notice of requirement
Wellington Water, on behalf of Porirua City Council (PCC), will lodge a notice of requirement (NOR)
for an alteration to an existing designation under the Resource Management Act 1991 (RMA) with
PCC, for the construction and operation of the new Aotea reservoir.
What is a NOR?
The purpose of a NOR is to seek approval under the RMA to undertake an activity on a site. A NOR
also protects a site from being used for other purposes while the proposed activity is being assessed
under the RMA. If the NOR is confirmed the site will be designated for that purpose in the Porirua
City District Plan. Designations are commonly used to secure sites (and planning approval) for public
infrastructure projects.
What process will be followed?
Wellington Water will lodge its NOR with PCC in June 2018.
Once the NOR has been lodged, the process will be run and controlled by PCC. Wellington Water
will be requesting public notification to enable the public and all interested stakeholders to have
their say. The submission process will be run by PCC.
Depending on the nature of submissions received, PCC may choose to hold a hearing where
submitters can speak to their submissions.
When would construction start for the new Aotea reservoir?
Subject to receiving approval, the provisional construction start date is 2021.
Where can I get more information?
More information on the project is available at www.wellingtonwater.co.nz/work-in-your-area/
porirua-reservoirs or you can email poriruareservoirs@wellingtonwater.co.nz
wellingtonwater.co.nz/work-in-your-area/porirua-reservoirs
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