Lake Rotoiti is a lake in the

Bay of Plenty The Bay of Plenty () is a large bight (geography), bight along the northern coast of New Zealand's North Island. It stretches from the Coromandel Peninsula in the west to Cape Runaway in the east. Called ''Te Moana-a-Toitehuatahi'' (the Ocean ...

region of

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

. It is the northwesternmost in a chain of lakes formed within the

Ōkataina Caldera Ōkataina Caldera (Ōkataina Volcanic Centre, also spelled Okataina) is a volcano, volcanic caldera and its associated volcanoes located in Taupō Volcanic Zone of New Zealand's North Island. It has several actual or postulated sub calderas. The ...

. The lake is close to the northern shore of its more famous neighbour,

Lake Rotorua Lake Rotorua () is the second largest lake in the North Island of New Zealand by surface area, and covers 79.8 km2. With a mean depth of only 10 metres it is considerably smaller than nearby Lake Tarawera in terms of volume of water. It i ...

, and is connected to it via the Ohau Channel. It drains to the

Kaituna River The Kaituna River is in the Bay of Plenty region of the North Island of New Zealand. It is the outflow from Lakes Rotorua and Rotoiti, and flows northwards for , emptying into the Bay of Plenty at Maketu. It was the subject of a claim concern ...

, which flows into the Bay of Plenty near

Maketu Maketu is a small town on the Western Bay of Plenty coast in New Zealand. It is located roughly from Paengaroa, from Te Puke, from Tauranga, from Rotorua and from Whakatane. Maketu has an estuary from which the Kaituna River used to flow, ...

. The full name of the lake is Te Rotoiti-kite-a-Īhenga, which in the

Māori language Māori (; endonym: 'the Māori language', commonly shortened to ) is an Eastern Polynesian languages, Eastern Polynesian language and the language of the Māori people, the indigenous population of mainland New Zealand. The southernmost membe ...

means "The Small Lake Discovered by

Īhenga Īhenga was an early Māori people, Māori explorer and rangatira of Te Arawa. After burying his father at Moehau, he travelled to Maketu to be purified by his uncle Kahumatamomoe, whose daughter he married. He explored the North Island and name ...

", the

Māori Māori or Maori can refer to: Relating to the Māori people * Māori people of New Zealand, or members of that group * Māori language, the language of the Māori people of New Zealand * Māori culture * Cook Islanders, the Māori people of the Co ...

explorer also credited with discovering Lake Rotorua. Legend says that the lake was named as such because when Ihenga first saw it, he could only see a small part of it and thought the lake was a lot smaller. Since the 1960s, the quality of lake water has been negatively affected by inflows of nitrogen rich water from Lake Rotorua, agricultural run-off from surrounding farms and seepage from domestic

septic tanks A septic tank is an underground chamber made of concrete, fiberglass, or plastic through which domestic wastewater (sewage) flows for basic sewage treatment. Settling and anaerobic digestion processes reduce solids and organics, but the treatment ...

. The effects of this included an almost permanent

algal bloom An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in fresh water or marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term ''algae'' encompass ...

in the Okere arm of the lake and choking lake weed growth in other still areas of the lake. A barrier to divert the nutrient rich waters of Lake Rotorua into the Kaituna River was completed in late 2008. The

Bay of Plenty Regional Council Bay of Plenty Regional Council () is the administrative body responsible for overseeing regional land use, environmental management and civil defence in the Bay of Plenty Region of New Zealand's North Island. It was founded as part of the 1989 N ...

is expected to see improvement in lake water quality within five years. The Rotorua Te Arawa Lakes Program reported in 2013 that the intervention has significantly improved water quality. Water quality is the highest it has been in decades, and it is on track to meet targets set by the Program to meet community expectations. Lake Rotoiti has thermal hot-spring baths on the southern shore which are accessible by boat.

Geology

Its joint drainage with

through the Ohau Channel depends upon the sinking Tikitere

graben In geology, a graben () is a depression (geology), depressed block of the Crust (geology), crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German language, German, meaning 'ditch' or 't ...

which is also very geothermally active on the south eastern margins of the lake. There appear to have been Rotoiti eruptive vents at the eastern end of the lake and although these are part of the Ōkataina Volcanic Centre they are believed to be in an area of collapse subsidence outside the north western margins of the

itself. This region of the caldera was at one time termed the

Haroharo Caldera The Haroharo Caldera (Haroharo volcanic complex) is a postulated volcanic feature in Taupō Volcanic Zone of the North Island, New Zealand within the larger and older Ōkataina Caldera. Since 2010 further studies have tended to use the terms H ...

, but has been renamed in the more standard major event fashion to the Rotoiti Caldera. As postulated, this caldera does not house the lake. The age of this large eruption of more than of magma was historically ill-defined due to several complexities and the literature gives a range from 40,000 years to 64,000 years ago with 47,400 ± 1500 years ago being recently quoted. What is not now challenged is that this was a paired eruption with a nearby vent in the

that had a separate magma source and erupted Earthquake Flat

breccia Breccia ( , ; ) is a rock composed of large angular broken fragments of minerals or Rock (geology), rocks cementation (geology), cemented together by a fine-grained matrix (geology), matrix. The word has its origins in the Italian language ...

.Houghton B F, Wilson C J N, McWilliams M O, Lanphere M A, Weaver S D, Briggs R M, Pringle M S, 1995
Chronology and dynamics of a large silicic magmatic system: Central Taupo Volcano Zone, New Zealand
Geology, 23: 13-16.

Climate

Notes

References

{{DEFAULTSORT:Rotoiti, Lake, Bay of Plenty Lakes of the Bay of Plenty Region Okataina Volcanic Centre Volcanic crater lakes