A Group History

Interferences and restoration

The Kaiwharawhara Stream valley (and tributary Korimako Stream) suffers from a legacy of interferences over nearly 180 years - early logging and farming, road, rail and sewer developments, slips, weed escapes, rubbish from adjacent areas and pollution from the huge catchment area. Fast stormwater run-off from hard surfaces in the catchment turns the streams into destructive torrents. Weed species of all types flourished, carpeting forest floors and smothering re-growth. Possums, rats, stoats, hedgehogs and mice badly affected the ecology. Waterfalls in the stream at culvert outlets blocked the migration of native fish. Flooding, pollution and sedimentation affected fish and invertebrate life.

Much of the restoration work described below has attempted to mitigate these effects and to restore the park to a native bush wilderness. Up to the end of 2024, more than 95,000 plants have been put into the ground and maintained. A TPG team has serviced the network of traps and bait stations throughout the park for animal pests. Bird numbers and species have increased markedly and there have been no possums for two decades.

The Trelissick Park Group (TPG) and the community are grateful for the funding, donations and plants from many sources, assistance from WCC and GW, and for the hard-working volunteers, organisations, corporate and school groups who carry out the work. The TPG also participates in various workshops, displays, guided tours of the park, and presentations to various groups. It has assisted with academic studies and published articles. It is actively involved in the lower Kaiwharawhara stream and estuary area, as it is part of the ecological corridor. Further details of that involvement are in the Current Issues page of this website.

More details are available on these pages of the website:

• History – includes 'Onslow Historian - The History of the Trelissick Park Group 1991-2013'
• Gorge Gazette
• Minutes of meetings.

Early restoration – 1940-1990

There was some restoration work by a local resident from 1941. The Wadestown Residents' Association (WRA) was heavily involved from the 1960s to 1980s, advocating for removal of gravel heaps from the main valley and mustering opposition to the proposal to use the valley as a landfill. WRA developed a plan to clear the old tracks and plant nectar-bearing trees to attract birds. Trees were planted on the main track between Hanover Street and Trelissick Crescent. There were many work parties. Attacks were made on blackberry, sycamore and old man’s beard. An area of railway land below Wadestown was leased to WCC.

1991 – 1994

The gravel heaps galvanised the Ngaio Progressive Association (NPA) into action and the Trelissick Park Group was formed in June 1991, with the name Trelissick Park/Ngaio Gorge Working Group. After the gravel heaps were spread, the first planting was in the Kaiwharawhara valley.

A draft development plan was prepared. WCC assisted with implementation, including weed control and maintenance. TPG sought definition of park boundaries. Funding was discussed. Concerns to be addressed included moving the debris trap, smells, water quality (leachate, mud), silt and gravel in the stream from erosion and subdivisions, bulldozing in the stream bed, industrial pollution beyond the park, old sewer pipes, possums and lack of liaison within WCC.

A vegetation plan was prepared, with lists of suitable plant species. WCC and F & B nurseries supplied the plants. An adopt-a-spot scheme was initiated. WCC strengthened the Kaiwharawhara stream banks with rocks and rock gabions, removed old sewer pipes and improved tracks. WCC commissioned a stream management plan.

Wightwick's Field in the Korimako Stream valley was gifted in a hand-over ceremony in August 1993. The old industrial area adjoining the lower end of the Kaiwharawhara valley was purchased by WCC in 1994. The associated magazine and stone wall became Category II Historic Places under the Historic Places Act.

The Kaiwharawhara Reclamation Working Group was set up by TPG and HPPA to deal with issues at the lower end of the Kaiwharawhara Stream and estuary. TPG made submissions on developments in the catchment affecting the park, for example, fast stormwater run-off, sedimentation and pollution (continued over subsequent decades). The first Gorge Gazette was distributed around the community in 1994. To recruit more volunteers, there were meetings with the local community, letter drops and newspaper publicity.

1995 – 1999

The Trelissick Park Management Plan was issued by WCC in 1995. A Trelissick Park Five-Year plan was prepared by TPG (updated periodically since then). Work started on removal of the industrial buildings at the newly purchased site in the lower Kaiwharawhara valley.

Tools were purchased and WCC provided a scrub-cutter. Regular working bees were held. WCC removed pine trees from the park next to Hewett Way in Ngaio. WCC deployed bait stations for control of rats and possums and GW serviced them. Funding was obtained for dealing with sycamores on the covenanted land below Hanover Street.

Under pressure from TPG, HPPA and others, WCC rescinded a decision to sell conservation land down to the stream below a WCC-owned house at 112 Oban Street. In 1996, they decided to sell only the part with the house, saving the lower section for the park. A narrow strip between 112 and 114 Oban Street was retained as a legal right of way for access to the park in 1999.

WCC purchased private land below Waikowhai Street for the Northern Walkway entrance. The gorge was cleared of more old sewer pipes by helicopter.

2000 – 2004

Work was just starting on restoration of the magazine when, in December, a Chubb security van was robbed of nearly $1 million in the city and set alight inside the magazine, destroying the roofing. Work changed to preserving the historic buildings as a ruin.

The park was designated as a Key Native Ecosystem, so had priority for restoration work by GW. In 2002 Project Kaiwharawhara was born. This stimulated much riparian restoration work in the catchment right down to the harbour by GW and WCC. Four blackberry slopes in the park were sprayed in 2002 by helicopter, with a repeat in 2003. WCC and TPG then planted these areas, some aided by helicopter transport. Fire damaged gorse and some plantings below Trelissick Crescent. TPG received GW Take Care funding for re-vegetation in the catchment, including in the park.

A fenced legal right of way was obtained by WCC for the Northern Walkway to go along the riparian strip north of Wightwick’s Field. A new bridge was built to link this with the track from Waikowhai Street. This allowed the Northern Walkway to go directly down to Wightwick's Field from Waikowhai Street.

The debris trap was upgraded in 2002. WCC removed old sewage pipes, some by helicopter. Earthquake strengthening of Ngaio Gorge Road commenced. Five private properties below Hanover Street were registered as covenanted to the QE II Trust in 2002 - thought to be a first for an urban area (the first registration occurred in 1999). A TPG website was started.

In 2004, WCC upgraded the whole magazine area down to the entrance from Kaiwharawhara Road. The concrete slab for the old plastics factory next to the magazine was removed.

2005 – 2009

In early 2005, a nocturnal fish walk up the Kaiwharawhara Stream revealed a range of native fish, signifying reasonable stream health. In 2006 fish passages were constructed at the exits of the tunnels under the railway line and Churchill Drive. WCC removed more old sewer pipes from the stream. Under the MfE Sustainable Management Fund, a part-time coordinator recruited and nurtured more adopt-a-spot volunteers. Publicity raised the profile of the park and the adopt-a-spot scheme and increased the spots to 30. Health and Safety information and guidelines were prepared for volunteers working in the park.

The new Korimako valley track was completed early in 2005 and 4 new bridges in 2006. Use of the park increased markedly and cyclists became more of a problem. In conjunction with the new track, 2 sites in the Korimako valley on railway land were leased to WCC in 2006. These were flat riparian areas clothed in blackberry. The GW Take Care fund was used to cut and spray the blackberry and then replant the area in 2007. In 2007-8, easements were obtained and the Forest Remnant Track was upgraded to tramping track standard. A "reveg. track" was installed below Hanover Street. The park map was updated to show track names and bridge numbers. Seats, map and information boards at entrances, an interpretative board next to the magazine, brochure holders and a new table and benches for Wightwick’s Field were installed.

In 2007, TPG's name was simplified to Trelissick Park Group from Trelissick Park/Ngaio Gorge Working Group. A logo for TPG was organised. The Gorge Gazette was re-started. Brochures were produced for park entrance brochure holders. In 2008, DOC instigated a Community Conservation Fund, which allowed for blackberry spraying and plants to go in on a riparian strip on railway land downstream of bridge 5. TPG took over servicing of bait stations and mustelid traps, in conjunction with GW.

The railway lines in the tunnels had to be lowered to fit the new carriages. Access was required via the slope opposite the magazine for heavy machinery, with a temporary bridge across the Kaiwharawhara Stream. Riparian plantings on both sides of the stream and on the slope above had to be sacrificed. Ballast was stored on the flat area next to the magazine. On completion of the railway work, Ontrack had an Open Day early in 2009 to walk the line. Ontrack provided two picnic tables, next to the magazine made from railway sleepers.

2010 – 2014

In 2010 the park became off-leash for dogs, but with the requirement for dogs to be under owners' control at all times. A huge slip above the Kaiwharawhara Stream tunnel under the railway line blocked the Korimako Stream flow for a while. In 2011 the website content and layout was refreshed and in 2012 TPG started a Facebook page. Sadly the park lost many flax afflicted by yellow leaf disease. The tradescantia leaf beetle trial was unsuccessful. Another large slip from the railway line in Wadestown in 2012 cut the Northern Walkway, damaged the seat and went right down to the valley floor. 2013 was a year of extreme weather. A severe summer drought fortunately had little effect on the plantings. Very heavy rain in May was sufficient to attract a kayaker for adventure in the streams. Bad southerly wind storm in June caused some tree falls and much debris.

Rip-rap rock was placed in the gulch below Hanover Street to mitigate stormwater erosion. A garage was removed from upper Ngaio Gorge Road. Gabions were installed at bridges 4 and 5 to protect foundations from erosion. A seat at the grassy spot on railway land between bridges 4 and 5 was installed, funded by local community members. TransPower strengthened their pylon foundation. Signage was upgraded to include the new Te Araroa Walkway and the Sanctuary to the Sea Walkway. The historic walls bordering the vehicle access track from the lower Ngaio Gorge Road entrance were restored.

Surveys of residents by the community in 2010 and 2016 showed majority support for a track down into the park from Oban Street. The idea of such a track was raised as early as 1981 by WRA in their submission on WCC's Draft Trelissick Park Management Plan and a possible route was developed. It was later listed as an access policy in the WCC Trelissick Park Management Plan of 1995. TPG advocated at various times thereafter for this track and benched an access track for animal pest control. Investigations by WCC concluded that alternative access locations from Wadestown and Highland Park were not feasible.

Fish passage at the debris trap was improved when Capacity removed the rocks in 2013, retaining the vertical rails to catch the debris. The stream bed no longer coated with silt. TPG produced 'The History of the Trelissick Park Group 1991-2013' for the OHS 'Onslow Historian', launched early 2014. In 2014, GW withdrew the Key Native Ecosystem status from the park. WCC took over much of the pest control work from GW. Most of the TPG documentation was archived in the OHS premises at 98 Khandallah Road. KiwiRail carried out pest weed control along railway land, with some bi-kill in the park. Reparation plants were provided.

2015 – 2019

2015 – An eel sign was installed next to the debris trap and a weta hotel was put below Trelissick Crescent entrance 4. Website changes included new weeds, plants and history pages. A plaque discovered in weeds was installed on a track-side seat below Hanover Street (story in November 2015 Gorge Gazette). A complete rupture of the sewer line caused serious pollution in Korimako Stream.

2016 – Clearance and planting of 57 Kaiwharawhara Road commenced. New rubbish bins were installed int he park. Bait stations were changed to use block bait following dog poisoning from pellets. Two Goodnature A24 self-resetting traps were installed (with more added since then - now 12 total in 2022). Wellington Water installed a sewer water quality monitoring panel in Kaiwharawawhara valley. A price and drawing was obtained for a suspension bridge across the Kaiwharawhara Stream for the track from Oban Street.

2017 - Twenty new pellet-filled Bait-safe stations were installed by GW for possums (serviced by GW). The old bridge opposite Wightwick's Field was removed (undermined foundations). Serious sediment pollution occurred from a housing development at the end of Silverstream Road. Bridge 3 was damaged from flooding and was replaced. New gabions were installed for bridge 2 and to protect the bank down from Wightwick's Field. VUW students studied animals in the park, using motion-detecting cameras. Zealandia reignited Project Kaiwharawhara, calling it Sanctuary to Sea, expanding Zealandia's horizons and involving more interested parties. A huge slip below the railway required extensive reinforcement, accessed by a temporary bridge.

2018 - Comprehensive plant and weed lists were added to the website and the history section was expanded. The Northern Walkway from the Waikowhai Street entrance to bridge 1 was upgraded. Northern Walkway signposts were installed. Investigations and discussions for park access from Oban Street, Wadestown, were on-going, with WCC conducting a residents' survey. WCC then agreed the project could proceed, with funding for a new footbridge across Kaiwharawhara Stream raised by the community. GW installed continuous stream monitoring equipment in the lower Kaiwharawhara Stream.

2019 - Fund-raising and preliminary work for the access from Oban Street and new Kaiwharawhara Stream footbridge to connect with the existing track network underway. Replacement of small footbridge on Northern Walkway below Hanover Street.

2020 – 2024

2020 - Construction and completion of access from Oban Street and new Kaiwharawhara Stream footbridge (bridge 7). New seat to replace old seat bench below Trelissick Crescent entrance 3. Recent major slips above Ngaio Gorge Road required re-routing of road and restriction of access. Remediation and increased car-parking work started in October 2020, ongoing until mid-2023. The lower part of the park and lower entrance closed for the duration. TPG awarded Volunteer Wellington Corporate Challenge Mahi Award in conjunction with Treasury and Victoria University. The Wellington Interfaith Council planted 51 iconic trees near bridge 6 to commemorate the Christchurch Mosque victims

2021 - Upgrade of Northern Walkway from Hanover Street to bridge 6. New seat to replace old bench on Northern Walkway (below transmission tower) to commemorate the Christchurch Mosque victims, funded by Wellington Interfaith Council. Heavy rain and stream flooding wrenched bridge 4 from its foundations and washed it against bridge 5. A huge log-jam in Korimako Stream below Waikowhai Street undermined sewer pipe foundations. WW commenced replacing those sewer pipe foundations.

2022 - 80 plants provided by WW as reparation for damage during repair and upgrade of sewer system on Korimako Stream banks below Waikowhai Street. New sewer line crossing the lower Kaiwharawhara Stream installed. TPG submission on WCC’s proposed district plan raised continuing concerns about fast stormwater runoff from the catchment and the need to ensure more than "hydraulic neutrality" of run-off from new housing developments and infill housing. Bridge 4 replaced. Problems with plant thefts and garden waste dumping at Trelissick Crescent verge. TPG meeting venue changed from OHS room at 98 Khandallah Road to the Ōtari Wilton’s Bush visitor centre. More stream bank damage and silt deposition from winter storm.

2023 - GW, in partnership with WCC, Ngati Toa and others, received funding from MfE to improve fish passage. GW doing a trout survey upstream of the ramp at the tunnel exit under the oil tank before proceeding. Ngaio Gorge Road stabilisation project completed, including two new lay-bys and planting and information board at lower park entrance. TPG planted grasses next to the upper lay-by. Northern Walkway below Hanover Street re-routed to avoid large gouge created by stormwater from railway line. Track downstream of debris trap and downstream of bridge 5 re-routed following severe stream bank erosion. TPG continues collaboration with S to S, who recruited local businesses for work in the park. The collaboration included lodging a submission on the draft WW Stormwater Management Strategy. New seat installed at the end of bridge 7. Initial blackberry clearance for a podocarp grove on the true right bank upstream of bridge 7. Received large $50K donation from Frances Lee. Individual TPG members lodged submissions on WCC draft dog policy review. Debris trap cleared and bent rails somewhat straightened. TPG plant order for 2024 included more ground-cover planting, following tradescantia clearances. New ferry facilities at the Kaiwharawhara estuary suspended by new government – monitoring by TPG and S to S suspended, waiting outcome. Inanga spawning project downstream of the Hutt Road bridge initiated by S to S in conjunction with TPG, Taranaki Whānui and others, to be funded by some of the above $50K donation. TPG reorganisation initiated with more sharing of workload. Two TPG volunteers received North Wellington Voluntary Service Awards.

2024 - New committee. Moved TPG archives to WCC archives at 28 Barker Street, Te Aro. Weed trees removed by TPG, WCC and KiwiRail. WCC developed a hierarchy for tradescantia control and targeted two areas. Put 3 pots of tradescantia infected with yellow leaf spot fungus (for spore dispersal) below Oban and Hanover Streets. Identified weed sites for WCC’s Kaitiaki o Ngahere to tackle, include OMB and jasmine. Concerns about channels cut by dogs below stream-side tracks – track edge boarding installed in some places. Frances Lee purchased a 0.25 Ha parcel of land below 128 Trelissick Crescent that was proposed for townhouse development and transferred it to WCC to add to the park. New seat opposite the Forest Remnant Track exit. TPG spoke to select committee on the proposed Fast Track Bill, concerned about initial lack of environmental provisions. Funding received from Transpower for upgrade of park signage. TPG spoke to its submission on District Plan Stream 11 ‘Ecosystems and Indigenous Biodiversity’, concerned about the environmental effects of infill housing and multi-unit subdivision. Some predator control team changes. Eight volunteers now involved in predator control in the park. Inanga spawning project, led by S to S, included weeding both banks and installing 4 planter baskets below Spotlight. Leak at both ends of 1913 sewer pipe down from bridge 6 fixed – expedited by S to S and Taranaki Whānui. Investigations for GIS project for Kaiwharawhara catchment continue with various parties. S to S pursued partnerships with businesses in the catchment – TPG has approached Mitre 10. TPG attended OWB open day, Wadestown fair and Ngaio community picnic.