Where a million litres a day would go

Approximately one million litres of wastewater a day. That is the volume the applicant's own material attributes to 1,200 dwellings at Arrow Junction, and it is the single most consequential number on the public record.

We are not going to multiply that figure out for you. We do not need to. A million litres is not a quantity that becomes alarming when annualised — it is a quantity that has to go somewhere every single day, in the same place, for as long as the development stands. The question is not how big the number sounds. The question is where it goes.

So follow it.

The chain, one link at a time

Wastewater from a dwelling does not disappear. It travels a documented path, and every link in that path has a capacity, a consent and a failure mode:

• Household. Kitchens, bathrooms, laundries. This is where the volume is generated and the only link the resident sees.
• Reticulation. The sewer network that has to be built, sized, maintained and paid for, and which has to reach the next link without loss.
• Treatment plant. Where the load arrives. A plant has a design capacity, and a plant receiving more than it was designed for does not fail quietly at a threshold — its performance degrades.
• Treatment. What is removed, and what is not. Treatment reduces contaminants; it does not delete them.
• Land application. Treated effluent applied to land — in this case, disposal at Morven Hill. This is the link the public argument almost always skips, and it is the one that matters most.
• Soil. The receiving medium. Soil has a finite capacity to hold and process what is applied to it, and that capacity is not the same everywhere or in every season.
• Groundwater. What is not held by the soil. This is the end of the chain, and it is the link with no gate on it.

Nothing in that sequence is contentious as a description. It is how wastewater works. What is contentious is that the public record currently describes the first links in detail and the last links barely at all.

Where the documented chain stops

The volume is published. The disposal location is named. Between those two facts sits the part of the case that decides it: how much land, in what condition, receiving what loading, under what limits, monitored how, and with what margin when the plant or the ground does not behave as modelled.

On each of those, the material available to us is a reference rather than an assessment. That is not an accusation. It is a statement about what has been put in front of the public, and it is the reason this article is classified as Applicant Evidence rather than as anything stronger.

Why land application is the pressure point

A treatment plant is engineering, and engineering can be inspected, upgraded and consented against a number. Land application is different. Once treated effluent is applied to ground, the performance of the system depends on soil, slope, rainfall, season and time. The receiving environment does not have an operator.

This is also where the nitrogen figure lands. The water, wastewater and nitrogen page sets out the full chain; the nitrogen article takes apart the 2.8 tonnes a year figure and shows why the same number means four different things depending on where in this chain it is measured. Phosphorus, which travels the same path and is not quantified anywhere we have seen, is dealt with in both.

The question, put plainly

Where does every litre go?

Not most of it. Not on average. Not under design conditions. Every litre, every day, including the days when it rains, including the days when the plant is not at its best, and including the day after the development is fully occupied.

That question is answerable. It is answerable with a land area, a loading rate, a soil assessment, a groundwater model and a monitoring regime, all of which exist as ordinary professional work in New Zealand. It has not been answered in public. Until it is, the volume is a claim about inputs with no published account of outputs.

What we are not saying

We are not saying the applicant has no answer. We are not saying the plant will fail, or that groundwater will be contaminated. We have no expert evidence and we do not pretend to. What we are saying is narrower and harder to dismiss: a million litres a day is proposed, the destination is named, the accounting between the two is not public, and a decision made without that accounting is a decision made without the most important fact in the file.

Commissioning the wastewater and hydrogeology work that would answer it is the second rung of our funding ladder — see Support the Investigation. Ridgeburn Limited may answer it at any time, at any length, and we will publish the answer in full: that is our standing right of response.

Evidence statement

Classification: Applicant Evidence

Status: The volume and the disposal location are the applicant's own; the fate of the volume is not independently verified and no assessment has been published to us.

Author: Ridgeburn Press · Evidence Desk

Last reviewed: 16 September 2026

Sources

1. Wastewater volume and disposal arrangements for the proposed Arrow Junction development, applicant material
2. Morven Hill land application area — extent, loading and consent conditions 

Assumptions

• The ~1,000,000 L/day figure is taken as the applicant states it, at full occupancy, and is not adjusted, annualised or averaged by us.
• Peak, wet-weather and infiltration allowances are not known to us.

What is not established

• The land area available for application, and the loading rate per unit of that area.
• The soil and groundwater characteristics of the receiving environment, and the monitoring regime proposed.
• What happens to the volume when the plant is not performing to design.
• Any quantity of phosphorus at any point in the chain.

Right of response

Ridgeburn Limited, Queenstown Lakes District Council and any person named here may respond in full. How to respond.