Riparian Planting in the Upper Clutha

With winter drawing to a close, the WAI team is gearing up to start spring planting. The Upper Clutha catchment has an extensive network of streams, rivers, wetlands, and lakes. Native forest and wetlands once flanked almost all the streams in this region. We don’t see this today, due to land use changes resulting from agricultural intensification and urban development.
Volunteers walking to the planting site with planting equipment
Volunteer group helping with planting and plant maintenance at Glendhu wetland.
Photo credit: Dion Andrews

The waterways in our region are home to unique ecosystems that require healthy, clean water to thrive and survive. It is part of WAI’s mission to help replant riparian margins with natives to increase water quality, enhance biodiversity, erosion control and improve amenity value. Since 2018, WAI has been undertaking planting with the help of funding from the Ministry for the Environment’s Freshwater Improvement Fund.

Riparian planting by the edge of Spotts Creek
We have planted 16,102 eco-sourced seedlings, helping create 5,004m of newly planted riparian margins across the catchment.

I am often asked what riparian planting is and so before the season commences, I want to share a little bit more about why it is so important.


What is Riparian Planting?

The word riparian is derived from the Latin word ripa, meaning ‘riverbank’. Riparian areas are the interface between land and a river or stream. They are important natural biofilters, protecting aquatic ecosystems from excessive sediments, polluted surface runoff and erosion. 

Planting native grasses, sedges, flaxes, shrubs and/or trees in riparian zones improves the health of waterways. So far, we have planted over 30 different plant species, each eco-sourced and locally propagated by Te Kākano. Each riparian zone requires careful planning due to varying moisture levels as you move away from the stream or river.

The diagram above breaks the riparian zone into different sections, primarily based on wetness. As you can see each of these zones requires different plant types and so each planting site is carefully assessed to ensure that they contain the right mix of plants.

Beyond increased water quality, riparian planting has a wide ranging benefits. As an organisation, WAI works to ensure that all of its activities benefit ‘whole of ecosystem’ and ‘whole of basin’. Rather than assessing standalone benefits, WAI aims to understand how plantings benefit the wider aquatic and terrestrial ecosystems. Some of the reasons we undertake plantings help us achieve our wider goals, include:  

  • As they grow up and the roots get deeper, the plants act as a natural filter, reducing the amount of sediment and pollutants that can harm the quality of our water. This means it is cleaner by the time it makes it to our lakes. A place we all like to hang out and go for a swim during the warmer months.
  • Restoring native margins creates natural bird corridors along our waterways.  
  • Once the plants have become established, they increase the stability of the banks, mitigating extreme rainfall events that will become more frequent as the climate changes.  
  • Banks of plants provide shade that decrease waterway temperatures. This can lead to reduced weed growth and also provides stable temperatures for aquatic organisms.  
  • The plants can help sequester carbon as they grow.  
  • By educating landowners about the importance of riparian planting we hope that new areas will continue to be planted.

Where do we plant?

Click on icons on the map to see details MAP KEY -+

Over the years WAI has planted across 15 different locations stretching all over the Upper Clutha catchment. These locations have been on a mixture of both public and private properties because we are prioritising sites that reduce run off and pollutants in our urban and rural waterways.

In partnership with Te Kākano, we have developed a strict site assessment criterion to ensure that each new riparian site will improve freshwater quality in our catchment over time. If you would like to find out more about our planting process, then take a look at our planting plan.


Planting is just the start…  

The physical process of planting is only a small part of the planting process. Long before a plant enters the ground, we ensure that all weeds have been sprayed and cut back and that the waterway is fenced from stock, to give the plants the best chance of survival.

In the weeks, months, and years after planting, the sites require care and attention, from watering drier locations to replacing plants lost in a big storm. We take responsibility in ensuring that as many plants as possible make it through their first 3 years and are mature enough to survive the sometimes-harsh conditions that Otago can offer. All our sites are monitored and maintained annually.

A WAI team member clearing weeds around young native trees
Plant maintenance being undertaken at one of our sites in the Cardrona Valley

How can you get involved?

Getting involved is the easy bit.  

From the beginning we have been very fortunate to partner with Te Kākano Aotearoa Trust, a local community-based native plant nursery, that specialise in propagating plants specifically from the Upper Clutha Catchment.

Te Kākano Aotearoa Trust logo

Te Kākano cultivates a significant number of the plants that we plant and organises volunteer plantings on public sites. If you would like to come along to one of these plantings or help out down at the nursery, then keep an eye out for future planting dates here.  

The next FIF planting will be on the 9th of October at Wishbone Falls (near Raspberry Flat carpark, Mt. Aspiring National Park).  

If you are a landholder that has an area you think could benefit from riparian planting, then please get in touch with me and I will guide you through the process.  


A thank you to our funders and supporters

Without you and the many others that have supported us across the years we would have been unable to plant. Our main fundraising partner is Million Meters, an initiative of the Sustainable Business Network that is seeking to restore at least one million metres of waterways across Aotearoa New Zealand. We are also grateful for recent donations received from the Robert C Bruce Charitable Trust and Pacific Collections Good Earth Foundation.

If you would like to help us plant more tress in the future, then please feel free to donate on our Million Metres fundraising page: Love Our Alpine Lakes.

Million Metres logo
two people in front of a freshly planted and rabbit proofed young native tree
Matt (Manager of the Wānaka Water Project) with Maia a volunteer at Glendhu wetland.

Visit the Wānaka Water Project page.