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Our Projects

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Channel naturalisation

Working with the HCC to create more aesthetic stream banks.



Over 27 000 of plants have been planted by volunteers. There are three main days for planting, usually in the winter months.

Only native species suitable for the environment are planted. The Hutt City Council funds these plants.

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Rishworth Reserve

Strengthening the flood-prone banks of the Stream at the end of Rishworth Street with plantings.

We're also looking to carry out surveys of the wildlife in the reserve. Click here for info


Citizen science surveys

Taking part in fish and wildlife surveys. We're currently seeking volunteers to help with surveying wildlife at Rishworth Reserve. Click below for our latest fish survey (Feb 2023)

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Rubbish collection

Rubbish in the stream has been steadily reducing. The 2019 law change around plastic shopping bags has made an impact. We are also hoping that the changes around domestic waste may also reduce wind-blown rubbish. Read the full report.

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2019-21 Weed Suppressant Trial

A joint venture with GWRC and HCC this is (probably) New Zealand's first scientific trial for effective eco-friendly weed suppressant.

An independent weed specialist has been contracted to run a trial. This two year trial has now been completed. We can confirm that two weed mat were the most effective in suppressing weeds - non-woven polypropylene and Brown Eco Weed Mat supplied by Pillar Products. We are now investigating these options further as to which is best. We will be able to publish the findings from this trial next year.

Read more here.

Cape pondweed eradication

Getting rid of a nuisance

The aquatic plant Cape pondweed (Aponogeton distachyos), is a South African species and has been in Waiwhetū Stream for more than 100 years. It was apparently deliberately spread in New Zealand as duck food although it may have been planted as an ornamental aquatic species.

Cape pondweed in Waiwhetū Stream was considered a nuisance weed by Greater Wellington Regional Council’s (GWRC) Flood Protection Group because its abundance impeded water flows.

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A community effort

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The local community considered it an environmental weed in that it reduced the aesthetics of the stream, caused extensive surface algal blooms in summer, collected floating domestic rubbish, captured sediment to enhance seedling establishment, and caused sediment to remain suspended in the water column creating muddy water.

Early in 2011, Dr Merilyn Merrett (Senior Lecturer at the Open Polytechnic (OP), Lower Hutt) used her knowledge of plant reproductive biology to undertake research into Cape pondweed. The OP supported Merilyn’s research and their campus borders the stream in the suburb of Waterloo.

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Merilyn’s research enabled an understanding of the growth, flowering, seed set, and root structure of Cape pondweed; knowledge that led to the development of a strategy to eradicate the weed.

Between September 2011 and May 2014, ‘pondweed’ volunteers from both the OP and Friends of Waiwhetū Stream (FWS) manually dug the weed out of the stream bed. The OP group met at lunch time on Fridays and the FWS group dug fortnightly on Sunday afternoons.


Volunteer effort was supported by both GWRC and Hutt City Council (HCC) by providing waders and gloves and also for the removal of piles of pondweed and very large quantities of other rubbish removed from the stream bed.

The total number of volunteer hours taken to remove Cape pondweed is in the vicinity of 1100 and the approximate number of  plants removed around 300 000; a remarkable achievement!

Since the weed has been removed, the stream bed is visible, water flows are much improved, algae growth during summer is much reduced, and there is less sediment deposition resulting in a 50% increase in riffle length.

Controlling aquatic weeds is very difficult. The removal of Cape pondweed in Waiwhetu Stream was an unique project and shows what volunteers can achieve with a research-based eradication strategy.


Getting involved

There are several ways you can volunteer:

Plantings: Turn up with good footwear, gardening gloves and a spade, although some are provided

Weed control:  Pulling out weeds, spraying or helping spread mulch.

Fish Surveys: Come along and count the fish on selected days.

Rishworth Reserve

Located at the end of Rishworth Street, come along every Wednesday at 10 am to help plant natives and carrying out weeding.

Rubbish collection: The first weekend in every month volunteers collect rubbish. Sturdy shoes or gumboots and good gardening gloves. Bags and pickers supplied. The stream is divided into sections and on a typical collection 40 people will collect over 20 bags of rubbish.

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Rishworth Reserve has been a successful replanting project and we are now asking for volunteers or students to carry out a baseline survey. Click here for info

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Up coming event dates


Weed Warriors - a new initiative. Contact Ros if keen:



Clearing Cape pondweed

Read about progress in removing Cape pondweed from the Waiwhetū Stream here
Also read about the celebration of the last pondweed plants being removed on Sunday 4 May 2014 here.

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