Local Government Magazine
3 Waters

Making a splash – Wellington launches country’s first above-ground emergency water network.

If the ‘big one’ had hit the capital a year ago, many Wellingtonians would have been without a water supply for 100 days or more. The situation is now very different.
A partnership between infrastructure specialists Cardno and council-owned utility Wellington Water has turned the traditional supply approach on its head. If, and when, disaster strikes, every resident will be able to access 20 litres of emergency water,
every day.

In the early hours of November 14, 2016, a 7.8 magnitude earthquake centred in Kaikoura hit Wellington. The shake highlighted the vulnerability of critical infrastructure, and woke up many teams in central and local government to the need for a rapid response to support recovery of the capital’s economy and communities.

A 5000-litre drum bladder provides water to a community tap stand.

A ‘city without water for 100 days’ may alarm many residents and it’s great fodder for headlines. But for council operators it is anything but fresh news. Knowing the scale of the problem, and driving the work to secure funding and the capability to do something about it, hasn’t been an easy road.

Mark Kinvig is Wellington Water’s group manager network strategy and planning. He says the group’s technical leadership, and its model of regional management, have been important in pinpointing the specific issues, and highlighting the vulnerability of the bulk water supply network.

The longer it takes to restore critical infrastructure, the greater the impact on the community and the local economy. Porirua and Wellington rely solely on long pipes that cross active fault-lines and a long-term disruption could see businesses leave the region and not return.

“Wellington’s drinking water network is made up of more than 2000 kilometres of buried pipes – and around 1400 kilometres are considered vulnerable,” says Mark. “Around 30 percent of our 149 water reservoirs are also considered vulnerable.

“If the full strength of the Kaikoura quake had hit the Wellington fault-line, the impact on our services would have been significant.

“The work we’ve done over the past three years with our suppliers and consultants has put us in a really good position to understand the movement of the Wellington Fault, and the impact that it would have on drinking water supply.”

The country’s first above-ground emergency water network goes operational later this month. At its heart will lie a network of more 300 water collection sites across Wellington. Water will be transported to these sites, and stored in “bladders” ensuring that, in an emergency, no-one has to go more than 1000 metres to collect their water.

“At the heart of our resilience work,” says Mark, “is our level of service resilience – providing 20 litres of emergency water for every person, every day, within 1000 metres of every home.”

Wellington Water’s operational plan, Community Infrastructure Resilience, rests on providing that level of service from day eight onwards.

“We’ve shared that vision with our shareholders and our client councils over the past three years,” says Mark. “And they have bought into that aspiration. We’ve also re-set our expectations around how long households will need to look after themselves.

“Based on the work we’ve done, we know that households need to look after themselves for at least seven days.

Searching for emergency water

Investigation into alternative water sources included assessment of all freshwater surface bodies. Although this investigation identified 11 surface water locations, it found huge gaps in the region for reliable emergency water sources.
Cardno found a solution by identifying the potential for groundwater aquifers within the fractured basement rocks of the region that could provide a sustainable withdrawal rate of one litre per second or greater. This is the minimal requirement to supply the population of the area.
Cardno was engaged to fast-track water resilience initiatives from the 80-30-80 strategy, which included the drilling of emergency groundwater bores.

“It will take us at least that time to start operating the emergency water network. Our clear household resilience advice is that every person needs 20 litres of water, for every day, for at least seven days. The traditional storage amount of three litres a day just doesn’t cut it in Wellington.”

Wellington Water has worked with infrastructure specialists Cardno to generate a recommended water supply resilience programme that is seen as industry-leading in its approach.

The strategic response to Wellington’s water supply challenge is captured in the “Towards 80-30-80” strategy. It demonstrates a number of recommendations to build resilience, and a long-term programme of investment options to reduce the number of days it takes to restore water to parts of the region.

The objective is to provide 80 percent of Wellington Water’s customers, within 30 days of a major earthquake, with at least 80 percent of their water needs.

Cardno’s technical director of infrastructure strategy Antony Cameron says it was only days after the Kaikoura earthquake that the community aspects of 80-30-80 strategy were stepped towards action.

“The focus was providing the community with alternatives to the network as a low-cost and quick solution to ensure residents would be able to access local sources of water.”

Work streams in 80-30-80 focus on factors such as complexity, cost, timeframe to deliver and value for money. Antony says this helped focus resources on projects that were likely to deliver the most resilience benefit in the final programme.

“The flexibility was proven in the speed that we were able to meet central government’s call to accelerate investment in water resilience initiatives at the end of 2016.

“The solid regional model and clear storytelling was an important part of securing funding in Budget 2017.”

Delivering the multiple strands of Community Infrastructure Resilience is programme manager Andy Brown. The work is co-funded through $6 million of central government funding, with Upper Hutt, Hutt City, Porirua and Wellington City councils matching the contribution with an additional $6 million together.

“With $12 million in funding, and just 12 months to do it, our team have worked with a challenging programme,”says Andy.

“The water sources need to be confirmed as viable, water treatment processes designed and established – but not for routine use. This is a big deviation from standard water treatment processes.

“Right now we’re in the thick of collaborating with Wellington’s emergency management sector to finalise the ‘how’ of the distribution network. Like everything about this programme, it is designed to be flexible. We can all be very proud of what’s been achieved for the people of Wellington within such a short time.”

Community Infrastructure Resilience Programme

The Community Infrastructure Resilience Programme is delivering 22 low-cost modular water treatment stations, a comprehensive water distribution network and an integrated emergency plan.

Antony Cameron says the key to unlocking water supply resilience is making resilience simple and communicating clearly. “To me, resilience is about asking what my friends or family would consider reasonable in the circumstances.

“We knew we would have a big problem on our hands but we needed some real data to get a good understanding of the scale of this problem.”

Cardno turned to the use of cellular analytics to understand how people move in and around the region. This data proved invaluable to the resilience team who quickly worked out there could be more than 100,000 people trying to walk out of Wellington City’s CBD alone.

It also helped confirm that the lack of transport across the region would effectively create 17 miniature islands until these transport routes were restored.

This information was a key foundation informing the community-centric approach. “The data told us we can’t be there, and even if we could, the response may be patchy,” says Antony.

“We recognised we needed to empower communities with local, resilient water services and water supply is provided within 17 emergency response islands, while also planning for a utility-led response”.

Community Water Stations

The Community Water Station is a containerised treatment station that treats water taken from local water sources. By mid-2018 there will be 22 of these stations strategically located around the Wellington region.

These water stations are an innovative and cost-effective solution. They supplement reservoir storage, ensuring each community has enough water to survive and to maintain hygiene.

The stations also store the bulk of the water treatment and distribution equipment that each community will need to extract, treat and distribute the water to residents.

Distributing water to communities

At each of the 22 community water stations there will be at least one 20,000 litre bladder. This is filled with water that has been through water treatment processes in the community water station – after it has been extracted from an emergency groundwater bore or taken from a stream or river. Potable water from the 20,000-litre bladders is, in turn, used to fill hundreds of 1000-litre transportable bladders – the vehicles carrying these bladders are the ‘pipes’ in the emergency water network.

Water collection points – with 5000-litre bladders – will be available at schools, parks, roadsides and community emergency hubs. The 5000 litre bladders are filled up with the water transported to them by the 1000-litre transportable bladders.

Utes, trailers and all available transport options will become the ‘pipes’ while the existing network is unusable. The distribution network has been modelled within each of the ‘islands’, to ensure everyone can access potable water no more than 1000 metres from their home.

Providing potable water

A complex water treatment system is housed within each water station container. At the surface water sites, the system is slightly larger than what is required at the groundwater bore sites. The water treatment system involves processing the extracted water through a disposable filter, a carbon filter, micro-filter, ultraviolet treatment as well as chlorination.

This article was first published in the June 2018 issue of NZ Local Government Magazine.

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