Caring about the environment

Valuing natural resources

Our social licence to operate relies on our demonstrating that we’re a responsible guardian of the natural elements on which we depend.

In FY20 we published our internal guidelines on environmental management and biodiversity on our website and invited our stakeholders to give us feedback on our approach.

The impact of our hydro schemes

Hydro generation itself only has an impact on water quality when water is diverted; however, water quality can be further compromised by a range of other activities that affect areas such as the Waiau and Waitaki river systems. Our preference would be for the water in these catchments to be as clean as possible. While we help to mitigate changes in water quality by, for example, releasing more water into waterways to dilute the effects of contaminants and slow down algal growth and weeds, these actions are not without their own consequences, affecting our profitability and reducing the renewable energy we can deliver to meet New Zealand’s power needs.

The Manapōuri tailrace discharges freshwater to Deep Cove (which is part of Doubtful Sound), this commenced 50 years ago when the scheme was first commissioned. All of the fiords in Fiordland have a low salinity layer, it is a function of the shape of the landscape and the fact Fiordland is a very high rainfall area. The ecology of all of the fiords is unique due to the presence of the natural low salinity layer, it is one of the reasons that black coral grows at shallower depths in Fiordland than is common in other marine settings.

When the scheme was first commissioned there would have been a spatial displacement of marine species at the point of the discharge in the head of Deep Cove. Since then the marine ecology of Doubtful Sound has been stable and healthy. That is demonstrated by the fact that sites in Doubtful Sound as recently as the late 2000’s were identified and protected as marine reserves due to their existing high marine values.

Many of the impacts we’re dealing with were not considered when the hydro schemes were approved. Establishing large-scale hydro schemes is hard to imagine now. The biodiversity impacts of the schemes are addressed by our funding of Project River Recovery and the Waiau Fisheries and Wildlife Habitat Enhancement Trust (the Waiau Trust).

Project River Recovery is Aotearoa’s longest-running conservation/business partnership; it has been in place in the Waitaki catchment for nearly 20 years. Funded by Meridian, the Department of Conservation works to preserve and restore braided river habitats in the Waitaki catchment through weed control of the riverbed and pest eradication to protect black-fronted tern/tarapirohe colonies and help kakī or black stilt recover their populations. The partnership has created more than 100 hectares of new wetlands.

The Waiau Trust has been operating in the Waiau catchment in Southland for 23 years. Its goal is to enhance stream and wetland habitats for fisheries and wildlife. To date it has completed more than 220 habitat-enhancement projects and access projects, enhancing a total 3,356 hectares of habitat.

Riverways are natural highways for adult native eels (tuna) needing to migrate to the sea from freshwater to complete their life cycle and to spawn in the Tonga Trench. They also enable juvenile eels (elvers) to return up-river to mature. Our structures stand in the way of these natural movements, so every year we move a large number of elvers and adult eels at Manapōuri, and a smaller amount in the Waitaki catchment. Once released, they can migrate successfully to and from the sea.

In Manapōuri there’s a large self-sustaining population of eels because it’s a national park and there’s no commercial catch pressure. In FY20 we moved around 45 kilograms of elvers and juvenile eels upstream and almost 4,000 adult migrants (equivalent to more than 6,000 kilograms) downstream. These results were the lowest to date due to flooding in November and December 2019 and lockdown restrictions due to the COVID-19 pandemic.

In the Waitaki catchment the population is much smaller. We caught and transferred just over 115 kilograms of elvers and juvenile eels upstream. Due to a much shorter season, only 34 adult migrant eels were moved downstream.

In Australia, Meridian Energy operates the hydro generators but we don’t own the dam infrastructure and we don’t control the flow of the water. The environmental impacts of these dam structures and the water use is the responsibility of WaterNSW.

Water consumption (Mm3)*

Mm3 FY16 FY17 FY18 FY19 FY20
New Zealand
Fresh surface water (lakes, rivers) 70,610 72,946 65,562 74,183 85,339
Water returned to the source of extraction at similar quality 56,481 61,499 53,823 61,832 72,994
Total net fresh water consumption** 14,130 11,447 11,739 12,351 12,345
Australia
Fresh surface water (lakes, rivers) 3,696 2,574
Water returned to the source of extraction at similar quality 3,696 2,574

* Municipal water consumption not reported as minimal and not metered. While in New Zealand we have no exposure to water stressed areas, in Australia our power stations are operating in areas that can suffer from drought. Note that we only hold the right to generate electricity from water passing through the dams associated with our Australian hydro power stations, we do not hold the water rights themselves.

**Fresh water taken from Lake Manapouri is released into Doubtful Sound, a marine environment, and is not altered in terms of water quality.

No serious environmental breaches

These projects form part of our collaboration with local authorities and other interested parties and were agreed to when our consents were originally granted. We continue to work closely not just with parties that use the waterways we share but also with local government bodies, particularly during consenting and through the submissions process, and we report regularly on our compliance with resource consent conditions. In FY20, we’re pleased to report, there were no prosecutions. We recorded 13 breaches of environmental compliance. None were serious and no significant adverse effects arose from the breaches.

Supporting the Kākāpō

In 2016 we became a National Partner of the Department of Conservation’s Kākāpō Recovery Programme. That partnership has contributed to critical research to help the species recover and has had a real impact in raising awareness of the plight of these precious native parrots. It’s not just our partners who benefit from these programmes; our staff too find them inspiring and many volunteer to help out in their spare time.

Planting 1.5 million trees

Last year we launched our Forever Forests planting programme to begin planting 1.5 million trees on 1,500 hectares of land around Aotearoa and to have these in the ground in the next five years.

In FY20 we started with land around our hydro stations, planting our first seedlings late in 2019 on land adjacent to the Manapōuri lake control structure. The trees are a mix of natives and exotics. In the long term the natives will take over, leaving a lasting legacy for future generations. Once the trees have all been planted, they’ll soak up the same amount of carbon as our entire Meridian Group emits, meaning we’ll be carbon neutral without needing to buy carbon credits.