The relationship between wai (water) and whenua (land) is that one sustains the other. Wai enables life; we grow our food from it, it’s in our DNA. Wai is about human wellbeing and connects us to our wairua (spirituality). However, we have a water problem. There is an undeniably worsening decline in the state of water quality in Aotearoa New Zealand through the impacts of increasing nutrients, sediments and pathogens.

Over 80 percent of river length in pastoral areas is not suitable for swimming in New Zealand. Whānau, hapū and other communities are working hard in local areas to restore mahinga kai (cultivation and gathering) practices and their awa (rivers) but there are often substantive water quality issues in another part of the water’s cycle or pathway. 200 million tons of soil, rich in microbiology, is being washed into the sea because of land that’s been cleared and is heavily eroded.

Mā te taiao e kōrero (a conversation with the natural world), the Living Pā is about repositioning our relationship with the things that sustain us.

The Living Pā considers water, especially wastewater, as a precious resource. All of the Pā’s water systems—drinking, grey, black, storm water – are being managed within the confines of the site and are taking into account how the development relates to the local ecology. To achieve this our 335 Building Services Engineers have responded with a highly technical water system.

The Living Pā’s roof will capture 100 percent of our water needs. When a water droplet falls on our roof it will come down to two 25,000-litre tanks under the deck between the wharenui and the building. It will then be UV treated and carbon filtered—potable water that will be the clean, healthy drinking water for the building’s occupants and visitors.

Greywater from the showers and basins will be collected in another 25,000-litre tank and used to flush the vacuum flushing toilets, go on the elevated gardens, and the surplus transferred to the adjacent Murphy building. We’re very lucky because the Murphy building, next door, is University property, and old enough that it has separate flushing and potable systems (there are still some tests to do). It’s a building that uses over 1 million litres of valuable, cleaned potable water each year just to flush toilets. We’re going to send Living Pā clean-enough-to-flush water to Murphy to save valuable potable water.

The hardest thing is how to deal with all the black water from bathrooms and toilets. Our 335 Building Services Engineers and Tennent Brown Architects have spent a bit of time trying to figure this one out. Normally you’d do a septic system, however that’s not going to happen on our tight urban site.

Those vacuum wharepaku mentioned, they are like aeroplane units and require only 0.7 of a litre to flush, as opposed to a normal 3–6 litres. The point is they will create less black water to have to manage. The units have small pipes that go to a thing called a membrane bioreactor that has a five-tank system. Like osmosis, there are boundaries in this system that will allows water to move through while the sludge stays onsite. The units will have to be cleared out periodically and the waste taken from the site. The Living Building Challenge requires that it go no further than 100km from the site and has to be used for beneficial use. This is about creating a closed loop and not relying on the city infrastructure and/or contributing to its overloading so you have to build more and more. And, it’s about being independent.

There’s so much more of interest in the project’s approach to wai; to stormwater, flood event water, what is and isn’t happening with the sewer plug in, revitalising and daylighting the culverted Kumototo stream. More to come.