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Whakamana te Waituna newsletter

February 2023

The six Whakamana te Waituna workstreams had a busy 2022. As we begin our final phase of the initial five-year project to restore the mana of the Waituna Lagoon and catchment, the Trust has been reflecting on whether we’ve achieved what we set out to, and what happens next.

The Trust received Ministry for the Environment funding in 2018 to take us through to about May 2023. The funding has enabled us to run the project office; purchase flood-prone land around the lagoon; invest in iwi through Awarua Runanga’s Te Wai Parera (land) Trust; operate several trial projects aimed at improving water quality as it moves off farms further up the catchment and down into the lagoon; organise the upgrade of the Waghorn Road Bridge; regularly clean up sediment traps and drains around the catchment; and work collectively for the greater good.

Last year:

• Dave Knight was appointed manager of the new Te Mahinga Kai Pa site, bordering the lagoon.
• Te Tapu o Tane were engaged to plant thousands of natives around purchased land.
• On-farm planting continued, providing plant-based filter systems for farm run-offs and stock barriers to waterways.
• New traplines were set bordering the lagoon.
• Planning for a Te Mahinga Kai Pa Predator Control Plan began.
• The project team evaluated its performance, to glean learnings that can be used for further Waituna and other Southland work.
• The annual fish survey gave us better information about what goes on in our streams.
• Planning was well underway to construct a trial wetland.

This year, we are planning some activities aimed at welcoming people down to Waituna. Look out for more information on that by following our Facebook page.

Bob Penter

Executive Director

Evaluation underway to help Waituna

Future work in and around Waituna Lagoon will benefit from an evaluation of the past five years of projects, those involved with Whakamana te Waituna say.

Executive Director Bob Penter says the Trust’s vision of restoring the mana of the Waituna Lagoon is a complex challenge that no single organisation or group can do alone or quickly.

“The partnership approach has been key to making progress and completing so many projects. It’s also important for the partners to reflect on what’s been done, the difference this has made over the past five years, and how the partners can build on this as they move forward with future activities,” Bob says.

The programme was unique in setting up an outcomes-based assessment framework at the beginning for both planning and subsequently evaluating the programme. As it draws to a close the framework is being used to help understand how the programme has contributed to the different outcomes.

Will Allen and Viv Sherwood were part of the team that developed the original assessment framework, and have returned to help the Trust with the evaluation.

“Evaluation is about asking ‘What? So what? And what’s next?’ People need to think about how their work has measured up and what they might do differently in the future,” Will and Viv say.

“What we do is work together with the key people involved to put together a performance story based on the existing information and monitoring that’s been done, as well as a series of workshops. A performance story presents evidence of how a programme has contributed to outcomes and impacts, that is then reviewed by both technical experts and stakeholders.

The aim is to tell the ‘story’ of a programme’s performance using multiple lines of evidence.”

This assessment is essential to help the partners focus on Trust achievements and outcomes to date, towards improving the mana of Waituna Lagoon, Bob says.

“And even more importantly this information and understanding will inform the partners’ decision-making for the future.”

Carran Creek selected for wetland trial

Whakamana te Waituna has approved a trial three hectare wetland at Carran Creek upstream of Waituna Lagoon.

The Trust has had several projects underway throughout the catchment which feeds water into the lagoon. The wetland project is part of its Contaminant Reduction workstream, led by Fonterra Senior Partnerships Manager Cain Duncan.

“We’ve looked at what is the best way to prevent contaminants from flowing down into Waituna Lagoon. A wetland can provide a very good filtering system to help with that process, if it is properly designed to target specific contaminants, i.e nitrogen. Work will now begin on creating a wetland on land around Carran Creek in the southern part of the catchment.”

The land was purchased recently for the Whakamana te Waituna project.

“We asked Tonkin & Taylor to have a look at the feasibility first. They came back and said we’re not going to make a huge difference to the current contaminant loadings entering Waituna Lagoon (as most contaminants come from Waituna Creek), but in terms of understanding the performance of a nitrogen targeting wetland in Southland conditions, identifying appropriate plant species and determining construction methods and costs– it was a good site. And we could build it on land already committed for the Whakamana te Waituna Trust.”

Tonkin & Taylor are currently looking at detailed designs for the wetland, including finalising how to get water into the area – the beds of Carran Creek, Waituna Creek and many other lowland waterways in Southland are low gradient, deeply incised systems, which makes this challenging.

Ongoing discussions have been occurring with Environment Southland consents staff on minimum flows required to be maintained in Carran Creek and consenting requirements for building the proposed wetlands.

If this trial is successful, the next stage will be working with the community to understand how the learnings could be used to create a larger scale wetland on the Waituna Creek side of the catchment and in other areas of Southland.

Waghorn Rd Bridge upgrade

Before Christmas the Southland District Council received the engineering design for upgrading the Waghorn RdBridge.

Roading Engineer Rob Hayes says the design includes putting in new beams and replacing the deck slightly higher than the current bridge deck. The design means the bridge will be strengthened so it can take 100% of Class one traffic (truck and trailer) .

A tender was due to be posted in late January, and would close late February. After the successful contractor was selected, materials would need to be procured and a workplan organised. Rob hoped the work would be finished by the end of the financial year (June 2023). The bridge will be closed while the upgrade takes place.

The work is expected to lengthen the existing bridge life by 20 to 30 years.

Fire prompts extra training and traps

DOC and Fire & Emergency NZ have been proactive in providing fire-fighting training for DOC staff to ensure capability is maintained, following last year’s Waituna-Awarua fire.

In August, 29 DOC staff from across the southern South Island along with 10 Fire and Emergency New Zealand staff participated in fire-fighting training at Awarua.

The fire took out several traplines and DOC has been reinstalling these across the Waituna–Awarua area.

Since the fire, DOC has been able to get better access to the Western side of the lagoon to lay new traps, to increase the survival chances of the native bird populations, in conjunction with bird breeding seasons.

It took a massive effort to fight last year's fire. As we move through another dry season, it’s really important that everyone is vigilant around fires and fire safety.

Next Environment Southland Waituna Catchment project underway

Environment Southland’s catchment operations team is working with a Waituna catchment landowner to help mitigate damaging bank erosion, in work complementary to the Whakamana te Waituna Trust’s stream bank erosion work completed in the lower Waituna Creek.

The catchment team is responsible for maintaining flood protection and land drainage assets on behalf of ratepayers across Southland. Catchment team leader Dave Connor says the work is vital in terms of protecting people and private infrastructure.

Waituna farmers pay an extra rate for bank stabilisation, separate to the land drainage rate towards these sorts of repair projects, and Environment Southland allocates around $40,000 each year to work on bank stabilisation in the Waituna catchment.

Bank erosion can result in loss of valuable farmland and creates issues in the receiving environment.

“It’s always a balance of what we’d ideally like to be able to do, and what we can afford to do now with what we’ve got. But also, we are very aware of climate change and associated modelling which emphasises increasing volumes of water coming down. This is highly likely to increasingly affect the land bordering the streams, creeks and rivers,” Dave says.

2021 was the first year the bank stabilisation rate was utilised.

"We worked on a project some 230m in length that involved strengthening the side of the outside bend bank, after the bank overhang was removed. Sediment from the substrate was removed along with trimming some willows that were redirecting the current. The landowner also agreed to fence a section of waterway previously open to stock access.

“This year in conjunction with relevant stakeholder groups and a landowner, the catchment team plans to clear the inside bend build-up in sections of the Waituna Creek, remove the sediment from the substrate where outside bend erosion has occurred, and stabilise the banks that are being eroded.”

Bank stabilisation work projects are currently identified through staff monitoring of the drainage networks, or requests from liaison committee members or request for service notifications from landowners. Staff then assess the site, and work with landowners and stakeholders on an approach that will best mitigate erosion or unstable banks specific to their site.

“We only have a small budget available, and there are around 80km of waterways in the Waituna rating scheme district. But this is a start, and heading in the right direction in terms of reducing the sediment input and protecting valuable farmland and infrastructure,” he says.

Annual fish survey results back

Whakamana te Waituna has received a report from the Cawthron Institute presenting the latest findings from a fish study in Waituna.

As part of the annual Waituna Creek fish surveys in 2019, 2021 and 2022, a stable isotope analysis was done to provide more information about the freshwater food web. This technique involves analysing tissue samples from fish and samples of a range of food sources, to find out what the fish have been eating and where it comes from.

According to the report, smaller fish such as common bully and īnanga tend to rely on food derived from their immediate habitat. For example, bullies living near the lagoon eat a higher proportion of lagoon food, while bullies living in the creek eat a higher proportion of food from the creek. In contrast, larger longfin eels and trout, which travel further, tend to eat a higher proportion of lagoon-derived food. This is true even for individuals living 7.5km upstream from the lagoon.

The study found that a large part of the eels’ diet consists of īnanga which have travelled up from the lagoon into the creek where they are eaten by waiting eels. Cawthron estimated that, in the lower 7.5 km of Waituna Creek, the longfin eel population and the trout population each consume approximately 1 tonne of īnanga, per year.

Community Ranger | Kaitiaki, Living Water - Waituna Pat Hoffmann says this research reinforces why providing good habitat for freshwater species is so important, especially in lowland waterways where water quality is more likely to be poor.

"Healthy and diverse ecosystems at the bottom of catchments can support healthier and more diverse fish communities further upstream. The research shows how critical freshwater restoration work is for providing habitat and food sources to ensure the survival of native freshwater species,” Pat says.

Media release: World Wetlands Day

Wetland restoration needs prioritisation

Thursday 2 February 2023

World Wetlands Day this year highlights the urgent need to prioritise wetland restoration, and internationally an entire generation is being called to take steps to revive and restore degraded wetlands.

Wetlands are disappearing three times faster than forests, and more than 35% of the world’s wetlands have been degraded or lost since 1970. Reversing this trend is critical, according to the Secretariat of the Convention on Wetlands.

The Whakamana te Waituna Trust, which oversees the rehabilitation and restoration of the Waituna Lagoon, supports the international global awareness campaign behind World Wetlands Day.

Trust executive director Bob Penter said a wide range of plants, animals, fish and birds call Waituna home.

“We are working with local landowners in the Waituna catchment to revive and restore the waterways that feed into the lagoon, to give the ecosystem the best chance of surviving into the future.”

Key trust initiatives in the past year include coordinating work carried out by partner organisations Te Runanga o Awarua/Te Runanga o Ngāi Tahu, Department of Conservation, Environment Southland, the Southland District Council and Fonterra (joint Living Water programme with DOC).

Some of the work being done includes farmers in the area being supported with on-farm planting and stream-bank erosion, planning is also underway for constructing a small wetland up the catchment from the lagoon and large ponds have been created on the Mahinga Kai Pa site.

Pest and predator control is underway, along with monitoring the fish and plant life, and engineering designs have been finalised for the upgrade of the Waghorn Rd Bridge.

“We have a number of things underway, and we’re pretty happy with what has been achieved to date over the past five years of the Trust’s existence,” Mr Penter said.

For more information on World Wetlands Day, visit www.worldwetlandsday.org. Information about Whakamana Te Waituna is available on its website www.waituna.org.nz or Facebook page.

Butterfly unique to lagoon and southern coast

The Tiwai boulder copper butterfly (Lycaena sp.) is endemic to the southern Southland coast and occurs nowhere else in the world. The species was first discovered in 1980 and has been recorded at just three sites: Tiwai Peninsula, Waituna Lagoon, and a stony area behind the sand dunes at the northern end of Oreti Beach.

Tiwai boulder copper butterflies rely on a plant called creeping pōhuehue (Muehlenbeckia axillaris) to complete their lifecycle. The caterpillars feed on its leaves, and the adults feed on its nectar, as well as the nectar of cushion plants and other flowers. Adults never stray far from the plant and can be seen sunbathing on it and performing courtship displays nearby. After mating, the females lay their eggs on the undersides of its leaves.

CREDIT: Images from: Patrick, B. (2020). Monitoring methodologies for four Lepidoptera taxa of southern Aotearoa/New Zealand. A report for the Department of Conservation, by Wildlands Consultants Ltd.

The butterflies have a wingspan of about 22 mm. Males are bright purple and females are orange with brown lines on their veins. Their wings have white undersides and a fringe of white hairs, which sets them apart from other species of boulder copper butterflies.