Avon Heathcote Estuary

Estuary of the Heathcote and Avon Rivers / Ihutai
Christchurch with its estuary
Coordinates	43°32′49″S 172°43′23″E / 43.547°S 172.723°ECoordinates: 43°32′49″S 172°43′23″E / 43.547°S 172.723°E
River sources	Avon River Heathcote River
Ocean/sea sources	Pacific Ocean
Basin countries	New Zealand
Surface area	8 km^2 (3.1 sq mi)
Settlements	Christchurch

The Estuary of the Heathcote and Avon Rivers / Ihutai is the largest semi-enclosed shallow estuary in Canterbury and remains one of New Zealand’s most important coastal wetlands. It is well known as an internationally important habitat for migratory birds, and it is an important recreational playground and educational resource. It was once highly valued for mahinga kai (Māori for food gathering).^[1]

Location

The Avon River enters the estuary from the northwest, and the Heathcote River from the south-west. The estuary has a triangular shape, a short inlet connection with Pegasus Bay, and is primarily enclosed by the 4-kilometre (2.5 mi) long Brighton Spit, on which the suburbs New Brighton, South New Brighton and Southshore are located.

The most prominent features of the inlet are the single deep channel between Rapanui Rock ("Shag Rock") and Brighton Spit.

The Avon Heathcote Estuary viewed from Redcliffs

Description

The estuary has an area of 8 square kilometres (3.1 sq mi), is shallow—the mean at high water of ordinary spring tides (HWOST) is 1.4 metres (4.6 ft)—and predominantly intertidal, as only about 15 percent of the area lies below low water of ordinary spring tides (LWOST).^[2]

Official name

The estuary's official name became Estuary of the Heathcote and Avon Rivers / Ihutai as a result of the Ngāi Tahu Claims Settlement Act 1998.^[3]

Avon-Heathcote Estuary Ihutai Trust

The Avon-Heathcote Estuary Ihutai Trust was formed in 2002. This resulted from requests from the wider community to act in the estuary’s long-term interests. The members of the Trust include representatives from the community, existing groups (Friends of the Estuary and the Christchurch Estuary Association), representatives from Christchurch City Council, Environment Canterbury, tāngata whenua and other agencies.^[4]

References

1. Newsletter, Estuary Trust, New Zealand, 2007.
2. Post-1847 changes in the Avon-Heathcote Estuary, Christchurch: a study of the effect of urban development around a tidal estuary, Royal Society of New Zealand.
3. "Ngai Tahu Claims Settlement Act 1998".
4. History, Estuary Trust, New Zealand.