Lake Taupō

Lake Taupō is a massive crater lake located on the North Island of New Zealand.

It sits within the caldera of the Taupō Volcano. A caldera is a large depression formed when a volcano collapses. This lake is the largest in New Zealand by surface area. It is also the second largest freshwater lake in Oceania. The town of Taupō sits on a bay on the northeastern shore.

The lake is drained by the Waikato River. This is the longest river in New Zealand.

The lake formed through intense volcanic activity over many thousands of years. The volcano has erupted 29 times in the last 30,000 years. Most of these eruptions ejected rhyolitic lava. However, Mount Tauhara formed from dacitic lava. A massive event called the Oruanui eruption occurred about 25,600 years ago. This was the largest known eruption in the last 70,000 years. It ejected 1,170 cubic kilometres of material. This massive event caused the land to collapse into a caldera. This caldera eventually filled with water to create the lake.

Another significant event is known as the Hatepe eruption. Scientists use tree ring data to date this event to approximately 232 CE. This eruption had a Volcanic Explosivity Index rating of 7. It ejected 100 cubic kilometres of material. In just a few minutes, 30 cubic kilometres were released. This was one of the most powerful eruptions in 5,000 years. It even caused the sky to appear red over Rome and China. The eruption expanded the lake and devastated much of the North Island. At that time, humans had not yet settled New Zealand.

Today, the lake supports a diverse range of life. The surrounding watershed is covered in beech and podocarp forests. Many types of ferns grow in the understory. Native species include northern kōura, which are crayfish. You can also find kōkopu, also known as whitebait. People introduced brown trout from Scotland in 1887. They also introduced rainbow trout from California in 1898. Smelt were later added as a food source for the trout. Near geothermal vents, tiny organisms called extremophiles live in the heat.

Geothermal activity is still present near the lake. Underwater hydrothermal activity continues near the Horomatangi vent. Geothermal fields and hot springs exist north and south of the lake. These include sites at Rotokawa and Tūrangi. The volcano is still considered active. Scientists from GNS Science monitor the area closely. The lake level is managed by Mercury Energy. They use gates built in 1940–41 to control the Waikato River. These gates help prevent flooding and conserve water.

Tourism is a major part of the local economy. The area has a temperate climate. In January, average daily maximum temperatures reach 23.3 °C. In July, the average maximum drops to 11.2 °C. Visitors enjoy many activities like skydiving and cycling. The Lake Taupo Cycle Challenge is a popular event. Some people even attempt to swim the 40.2 km length of the lake. In 2020, Michael Wells became the first person to breaststroke across it.

You can also see large Māori rock carvings at Mine Bay. These 10-metre-high carvings represent the navigator Ngātoro-i-rangi.

The lake holds deep cultural importance for the Māori people. The Ngāti Tūwharetoa iwi considers the lake a taonga. A taonga is a treasure or something very special. The Ngāti Tūwharetoa own the lake bed and its tributaries. They allow the public to access the water for recreation. The history of the area also includes tragic events. In 1846, a landslide covered a village called Te Rapa. This event killed 60 people, including the chief Mananui Te Heuheu Tūkino II. The lake remains a central part of the region's identity.