Abbreviations: WCC (Wellington City Council), GW (Greater Wellington Regional Council), DOC (Department of Conservation), TPG (Trelissick Park Group), NPA (Ngaio Progressive Association), HPPA (Highland Park Progressive Association), F & B (Royal Forest and Bird Protection Society), BotSoc (Wellington Botanical Society), WRA (Wadestown Residents' Association), OWB (Otari-Wilton's Bush Trust), OHS (Onslow Historical Society, MfE (Ministry for the Environment), QE II Trust (Queen Elizabeth II National Trust), WW (Wellington Water).
Footbridges over the streams are numbered 1 - 7 going downstream from the Waikowhai Street entrance. 'Magazine' refers to the Kaiwharawhara Powder Magazines.
The Kaiwharawhara Stream valley (and tributary Korimako Stream) suffers from a legacy of interferences over nearly180 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.
The Trelissick Park Group (TPG) and the community are grateful for the funding, donations and plants from many sources, assistance from WCC/GW and for the hard-working volunteers, organisations, corporate and school groups who carried out the work.
The TPG has participated in various workshops, displays, guided tours of the park, presentations to various groups, assisted with academic studies and published articles.
The TPG has been 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.
Up to the end of 2022, about 93,500 plants have been put into the ground. Bird numbers and species have increased markedly and there have been no possums for two decades.
More details are available:
There was some restoration work by a local resident from 1941. WRA was heavily involved from the 1960-1980s, advocating for removal of gravel heaps from the main valley and mustering opposition to the proposal to use the valley as a landfill.
A plan was developed by WRA 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.
The gravel heaps galvanised NPA into action and the Trelissick Park Group was formed in June 1991 with the initial name being the "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/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, eg from 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.
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 in response to a TPG request for control of rats and possums. GW serviced the bait stations. Funding was obtained for dealing with sycamores on the covenanted land below Hanover Street.
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).
In 1995 work started on removal of the industrial buildings at the newly purchased site in the lower Kaiwharawhara valley.
Under pressure from TPG, HPPA and others, WCC rescinded a decision to sell conservation land down to the stream containing a WCC-owned house at 112 Oban Street. They finally decided in 1996 to sell only the part with the house adjoining Oban Street, 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.
Work was just starting on restoration of the magazine in 2000. However, 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 was then changed to preserving the historic buildings as a ruin.
The park became a Key Native Ecosystem, so had priority for restoration work by GW. 'Project Kaiwharawhara' was born in 2002. This stimulated much riparian restoration work within the catchment by GW/WCC, right down to the harbour. Four blackberry slopes in the park were sprayed in 2002 by helicopter, with a repeat in 2003. WCC/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 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.
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. This raised the profile of the park and the adopt-a-spot scheme through publicity 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 the four new bridges in 2006. Usage of the park increased markedly and cyclists became more of a problem. 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 conjunction with the new track down the Korimako valley, two sites in the Korimako valley on railway land were leased to WCC in 2006. These were flat riparian areas clothed in blackberry. The joint OWB/TPG GW Take Care fund was used for the restoration. The blackberry was cut, sprayed, then planted in 2007.
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.
Late in 2008, DOC instigated a Community Conservation Fund, which allowed blackberry spraying and plants to go in on a riparian strip on railway land downstream of bridge 5.
In 2008 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.
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 in 2010 blocked the Korimako Stream flow, for a while.
In 2011 the website content and layout was improved/augmented and TPG started a Facebook page in 2012.
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 jointly 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 Ngiao 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/Highland Park were not feasible.
Fish passage at the debris trap was improved in 2013 when Capacity removed the rocks, retaining the vertical rails to catch the debris. The stream bed was then much better, with no more silt coating the bed.
In 2013, TPG produced 'The History of the Trelissick Park Group 1991-2013' for the OHS 'Onslow Historian' (launched early 2014).
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 - An eel sign was installed next to the debris trap and a weta hotel 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. Bait stations were changed to use block bait following dog poisoning from pellets. 2 Goodnature A24 self-resetting traps were installed (with more added since then - now 12 total in 2022). A sewer water quality monitoring panel was installed by Wellington Water in Kaiwharwawhara 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 any 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, so 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 protection/reinforcement - accessed by a temporary bridge.
2018 - Comprehensive plant and weed lists were added to the website and the 'history' section expanded. The Northern Walkway from the Waikowhai Street entrance to bridge 1 was upgraded. Northern Walkway signposts were installed. For park access from Oban Street, Wadestown, investigations and discussions were on-going, with a residents' survey conducted by WCC. WCC then agreed for the project to proceed, with funding for a new footbridge across Kaiwharawhara Stream raised by the community. Continuous stream monitoring equipment installed in lower Kaiwharawhara stream by GW.
2019 - Fund-raising and preliminary work for the access from Oban Street and new Kaiwharawhara Stream footbridge to connect with the existing track network. Replacement of small footbridge on Northern Walkway below Hanover Street.
2020 - Construction/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 early 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. 51 iconic trees planted by The Wellington Interfaith Council 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 wrenches bridge 4 from its foundations and washes it against bridge 5. A huge log-jam in Korimako Stream below Waikowhai Street undermines sewer pipe foundations. WW commenced replacing those sewer pipe foundations.
2022 - 80 plants provided by WW as reparation for damage during repair/upgrade of sewer system on Korimako Stream banks below Waikowhai Street. New sewer line crossing of 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 Khandallah Road to the Otari Wilton’s Bush visitor centre. More stream bank damage and silt deposition from winter storm.
Trelissick Park Group
Page last updated: 6 January 2023