Waimangu Volcanic Rift Valley
From the 1890s onwards, the valley has gradually been re-populated naturally by plants ranging from hot water-loving algae and bacteria to mosses and many species of native ferns, shrubs and trees.
These in turn support native birdlife including kererū, tūī, shining cuckoo, fantail, bellbird, and pūkeko, as well as introduced bird species such as mynah, magpie, finch and sparrow.
As a rare eco-system completely naturally re-established following a volcanic eruption, Waimangu is protected as a Scenic Reserve, administered by the Department of Conservation NZ.
The developing local native forest is the only current New Zealand instance of vegetation re-establishing from complete devastation without any human influence such as planting.
All vegetation in the Waimangu Valley was completely destroyed by the eruption and the area was covered in mud and volcanic ash on average 20 metres (66 ft) thick.
Further smaller eruptions continued throughout the 20th century, with the most recent one in May 1981 in the Raupo Pond Crater destroying the Mud Rift created there in 1906.
Colourful sinter terraces are visible on the western shore of Frying Pan Lake, and immediately east of Echo Crater was the site of the extinct Waimangu Geyser.
[10] The margins of Waimangu Stream from Frying Pan Lake to east of Inferno Crater are covered with delicate silica formations and colourful mineral deposits containing traces of arsenic, molybdenum, antimony, and tungsten, while the stream bed is home to blue-green algae and filamentous colonies of the photosynthetic bacterium Chloroflexus aurantiacus in a range of colours from bright green to orange.
The terrace is covered in blue-green algae, which cannot survive in the hot stream of water running down from the spring, providing a colourful contrast of green and orange.
North of this area, on the slope of Mt Haszard, is Inferno Crater, filled with a striking pale blue lake of highly acidic water with a pH as low as 2.2.
[11] The crater was blasted into the side of the mountain as part of the 1886 Mount Tarawera eruption event and remains the site of the largest geyser-like feature in the world.
The area in this open-sided crater features several small clearly visible hot springs and a prominent aggregation of layers forming a dam around a pale blue pool of silica-rich water.
The algae and bacteria form carpets of vivid hues ranging from orange to bright green and blue depending on water temperature and sulphur concentration.
A pest control scheme was introduced in 2000, and efforts are underway to ensure Patiti Island in Lake Rotomahana is kept pest-free.
Day trip visitors from Rotorua were keen to see the geyser erupting reportedly up to 460 metres (1,510 ft) high until its cessation in late 1904.
[10] Amenities provided in the valley include a visitor centre, opened in 2000,[18] a cafe and gift shop, and additional toilets near the Warbrick Terrace.
The visitor centre and car park are located along Waimangu Road, six kilometres (4 mi) from State Highway 5, fifteen minutes drive south of Rotorua.
The main walk through the Waimangu Volcanic Rift Valley comprises 3.6 kilometres (2.2 mi) of easy-walking wide gravel paths and boardwalks and is accessible via wheelchairs, except for Inferno Crater and the Mt Haszard Hiking Trail.
It is recommended to visit the geothermal features between Bird's Nest Terrace and the confluence of Haumi Stream and Hot Water Creek beforehand or back-track once the hiking trail re-joins the main path, to not miss out on them.
