Lake Wainamu

Size: 3.39 hectares

Area description

Lake Wainamu is approximately two kilometres inland from Te Henga / Bethells Beach. The lake is within Lake Wainamu Scenic Reserve and administered by Auckland Council as part of the Waitākere Ranges Regional Park. A small portion of the lake edge and buffering vegetation is on private property.

Lake Wainamu is identified as an Outstanding Natural Feature in the Auckland Unitary Plan.

Lake Wainamu.
Lake Wainamu in the Waitākere Ranges Regional Park is surrounded on all sides by scrub and broadleaved, podocarp forest. This western perspective reveals its connection with the Te Henga wetland.
Photo credit: Andrew Macdonald, Biospatial Ltd 2019

Key ecosystems

Lake Wainamu is the largest natural lake in the Waitākere Ranges. It was formed by the damming of deep stream valleys by sand blown inland from the coast. It is the only landform of this type in the region. 

The lake is up to 12 metres deep and is fringed by wetland. Wetland extends into shallow arms of the lake in several places. Machaerina sedgeland (WL11) is the most dominant wetland type closest to the shore. Raupō reedland (WL19) is more common in deeper water. The most common native wetland plant species here are:

  • kuawa
  • jointed twig rush
  • raupō
  • kuta.

Large mobile sand dunes separate the lake and beach. Regenerating native vegetation covers steep hillslopes around the rest of the lake. Kānuka dominated scrub (VS2) is common on the northern hillslopes while kauri, podocarp, broadleaved forest (WF11) is regenerating on the southern hillslopes.

Lake Wainamu.
Looking east, the large sand dune create a natural dam and Lake Wainamu.
Photo credit: Andrew Macdonald, Biospatial Ltd 2018

Key fauna

There is a good diversity of open water and wetland bird species here. Matuku hūrepo (Australasian bittern) and mātātā (fernbird) have been reported on the lake margins.

Kawau (black shag), kawau tūi (little black shag), and various waterfowl species use the lake regularly. Banded kokopu, an endemic freshwater fish, has also been found in Lake Wainamu. 

Related ecosystems

Regenerating ecosystem

Kānuka scrub and forest ecosystem (VS2)

Found throughout New Zealand, kānuka dominated forest establishes readily after fire. It's diverse range of flowering and fruiting shrubs and trees provide habitat for a wide range of invertebrates, birds and lizards.

Threat status
Least concern

Warm forest ecosystem

Kauri, podocarp, broadleaved forest ecosystem (WF11)

Once widespread across the Auckland region, this warm forest ecosystem contains a range of podocarp and broadleaf trees on different landforms. It is an ideal habitat for birds, bats and lizards thanks to an abundance of fruit and nectar.

Threat status
Endangered

Wetland ecosystem

Machaerina sedgeland ecosystem (WL11)

This critically endangered ecosystem occurs on the edges of lakes and shallow basins. It often occurs in a mosaic of wetland habitats including raupō reedland. Many native fauna species live here.

Threat status
Critically endangered

Wetland ecosystem

Raupō reedland ecosystem (WL19)

Raupō swamps are found in a wide range of areas on mineral soils and fluctuating water tables. They are dominated by raupō and other rushes and grasses, which provide a home for wetland birds.

Threat status
Endangered