Getting to know Ahuriri Lagoon

The Ahuriri Lagoon area in flood in 2013.

The Ahuriri Lagoon area in flood in 2013.

Ahuriri, or Ahuriri Lagoon, is a significant mahinga kai resource located on the Huritini/Halswell River between Taitapu and Motukarara. This lagoon was an important influence in the location of the Ngāti Koraha pā (village) complex located on the spurs directly above the lagoon and extending toward Motukarara.

 

Pre-drainage, this area was a large lagoon/wetland area surrounded by “koraha” or mudflats created by the pre-European lake levels of Te Waihora. Between 3-4 metres above sea level, Ahuriri would become fully integrated with the larger waterbody of Te Waihora. In particular, this wetland area supported a large harakeke (flax) wetland that gave rise to a large flax mill that operated during the mid to late 19th century.

 

Because of the productivity of this lagoon the area was extensively occupied by the Ngāti Koraha people. Pā and kāinga (fortifications and living sites) are located on the spurs directly above the lagoon and extend toward Motukarara. A small warm (geothermal) waipuna (spring) is also a valued and unique resource for this area.

 

A western-most tip of the spur (Te Mokopeke) that runs down from Gebbies Pass, juts out into the side of the Ahuriri lagoon. This site has important occupation and spiritual associations for Ngāi Tahu. There is also some small remnant dryland vegetation on this site that enhances its special link to past occupation.

 

As a result of mid-19th century claims by Ngāi Tahu to the Government regarding inadequate mahinga kai areas, Judge Fenton set aside a number of fishing easements for the various hapū in Canterbury. One such reserve, Te Koraha, was set aside adjacent to Ahuriri. The owners of this reserve are the hapū from Ngāi Tūāhuriri in the north to Ngāi Te Ruahikihiki in the south and includes the hapū of Te Pātaka a Rākaihautū/Banks Peninsula.

 

Unfortunately, due to the drainage of Te Waihora and construction of drainage channels throughout the Halswell catchment, Ahuriri was completely drained and the fishing easement rendered useless. The bed of the historic lagoon is now predominately pasture (with some remnant wetland sites) and is administered by Environment Canterbury. SH 75, the main road from Christchurch to Akaroa, passes through the area.

 

Ahuriri Lagoon area in flood, 2013

Ahuriri Lagoon area in flood, 2013

Ahuriri Reserves (also known as Ahuriri Lagoon) comprises 250ha and the area was first gazetted as a sanctuary for game birds in 1897. It provides protected breeding habitats for birds and fish, and a sanctuary for birds during hunting season.

 

Despite extensive drainage and pastoral development, Ahuriri Reserves are still by far the most significant wetland habitat in the Greenpark-Taitapu-Halswell-Christchurch Lowlands (outside of Te Waihora itself). Winter ponding provides extensive shallow margins, which attract thousands of wetland birds, both waders and waterfowl. These include black cormorant, black swan (kakī anu), Canada geese, paradise shelduck (pūtakitaki), mallard/grey duck (pārera), grey teal (tete), NZ shoveller.

 

Environment Canterbury land at Ahuriri is managed to Best Management Practice Standard and includes riparian planting and the managing of grazing and license conditions. Papatipu Rūnanga, the Te Waihora Management Board and Environment Canterbury are also forming a partnership with the intention of developing a 20-year plan for the restoration of the Ahuriri Lagoon area in Environment Canterbury ownership.

 

Whakaora Te Waihora already has a restoration planting programme underway and a cultural monitoring programme for Te Waihora as a whole is being developed and will be implemented by Ngāi Tahu. Some aspects of this programme will be relevant to the Ahuriri area.