SWE and SmartAudit

June 2018

Creating more sustainable use of water and power on vineyards at SWE

Leading Marlborough-based water engineering and irrigation company SWE is helping New Zealand producers to manage (and conserve) their water use, while creating significant savings in power usage and improving crop quality.

Stephen Leitch (managing director of SWE) is driven by a desire to create a sustainable production environment throughout Marlborough (and beyond). He studied horticulture at Lincoln University, and later Farm Dairy Effluent Design and Management with Massey University - and has been working in irrigation for over 20 years.

The Cawthron Marlborough Environment Awards are held every two years to showcase business or community projects that are good for the environment.

SWE (formerly known as Southern Water Engineering) is a leading water engineering & irrigation consultancy company in Marlborough that was formed in 2007. They work with irrigation, fertigation, stock water, effluent, and wastewater – as well as filtration, electrical and automation.. They service vineyards, wineries, dairy and other farms, and community amenities.

They have been recognised for business excellence through a number of awards, the most recent being in the Cawthron Marlborough Environment Awards. The company’s SmartAudit management system won the Business Innovation Award for 2017.

The company has created a suite of services, such as SmartAudit, and SmartWatch for its clients (including many vineyard owners) to reduce the resources they use, while continuing to run their businesses at an optimum level.

SWE has been responsible for much of the infrastructure development in Wairau Valley. They have worked on “green field” projects, as well as combining old and new technologies for clients.

SmartAudit was developed to help companies manage their water use and save on the power needed to pump it. Around 2,100 hectares of vineyards have been audited to date, and there have been significant potential savings identified.

SWE says if it is assumed that a SmartAudit identifies an average 10% power saving per season, it can be calculated that is a potential minimum saving to be made of $17 per hectare per year. This figure would amount to a minimum power saving across Marlborough of $400,000 per year - every year.

On top of this, there is often a saving associated with reducing the line charge, because the required capacity from the national grid is down (for example, from 55 to 30 kilowatts). On a Marlborough-wide basis, this would amount to a potential 2.5 million kilowatts less power wasted per year.

These calculations are based a very conservative (and easily achievable) saving of 10%. In fact, says SWE, vineyards that have been audited to date have seen savings of up to 50% (in which case, you can multiply the figures by five). To put these savings figures in perspective – the 2.5 kilowatt saving is enough to power 220 New Zealand homes for an entire year. (Source: www.physics.otago.ac.nz/eman/hew/ehome/energyuse )

SmartAudit identifies leaks or potential leaks in a water system, and the repair work and monitoring needed to improve the system, and conserve water and power usage. 

Stephen says it’s all about water efficiency - “We can no longer pretend all the water we want will be available, when we want it, without consequences.” SmartAudit also identifies where the distribution of water be improved, to ensure uniformity of production across an entire vineyard – it all goes to maximise efficiency and in turn, productivity.

SWE says if it assumes that a SmartAudit identifies an average of 5% potential water savings a year, it can be calculated to be a saving of 102 cubic metres per hectare per year. Across Marlborough this would total 2.3 million cubic metres of water use saved every year. This amount of water equates to 1,000 Olympic sized swimming pools – or the amount required to irrigate a further 900 hectares of extra land.

Again, according to SWE, the 5% represents a very conservative estimate of potential water savings. “We have regularly seen the potential for at least 20% savings in vineyard blocks audited to date”.

SWE also coaches companies about the need to collect data in order to conserve their water use.

Stephen says irrigation tools have improved significantly in the 20-odd years he has been in the sector. Improvements have been seen in everything from dripline to delivery methods, to pumping and monitoring systems.

SWE does their own design work and installation, providing everyone from engineers to electricians, so there is control over the entire process. As well as personnel, SWE has its own fabrication workshop, where items such as headworks, platforms for fertigation and electrical boards are produced, and materials repaired.

Marlborough’s vineyards currently cover an area of around 25,000 hectares (Source: New Zealand Winegrowers Vineyard Register Report 2016 – 2019) with potential further growth of around 5,000 hectares. Once that land is planted, and existing vineyards redeveloped, the only way to improve productivity is to manage resources more efficiently, including water.

Smart and efficient use of water will allow the ongoing viability of much of the primary sector activity in the region. Stephen believes around 30 - 40% of vineyards are still not monitoring their usage, so there is plenty of room for expansion.


The company has recently been carboNZeroCertTM certified. It’s one of two Marlborough companies currently to have this certification. (Yealands Estate is the other.) It means SWE now has an effective net zero carbon footprint, and the certification assures its clients, staff and community know they meet (or exceed) international zero carbon standards.

This achievement reinforces SWE’s commitment to environmental leadership. Stephen Leitch says as a business, SWE has integrated an environmental focus into company standard operating procedures. One of the ways it has reduced its carbon footprint is through the purchase of two electric bikes, currently used by Stephen and business development manager Dean Marshall. This measure has seen a major drop in their use of company cars, with over 4,500 kilometres travelled by e-bike in place of cars since the bikes were purchased in 2017.

Other staff members, such as Administration Team Leader Kath Langton, cycle to work. There are a number of good cycle trails around Blenheim being created, and Stephen is encouraging others (including his daughters getting to their holiday fruit-picking jobs) to make the most of them. He has been known to get on his bike and do exemplar runs to demonstrate to others that riding a bike won’t add more than 5 minutes to a journey to work.

Stephen has also encouraged a number of other businesses he works alongside to consider taking up the use of e-bikes. “We work, live and play in Marlborough. We want to make it a better place for our staff, our clients and our future generations.”

Stephen believes climate change of some description is a given and, “we need to be smarter in our responses to it, in order to be resilient to that change”. He believes attitudes and processes need to be industry led and believes the millennial generation is ready to pick up the challenge – he’s hopeful “people are beginning to get the message”. He says he’s grateful to be in position where he can make a difference through SWE – and that you need to have examples (and data) to show people just what can be achieved to encourage them to makes changes in their daily lifestyles which can make a difference. He adds that it is a long-term term challenge and solutions offered need to be practical.