Lake Rotorua

Lake Rotorua is the second largest lake in the North Island of New Zealand by surface area, and covers 79.8 km².[1] With a mean depth of only 10 metres it is considerably smaller than nearby Lake Tarawera in terms of volume of water. It is located in the Bay of Plenty region. The city of Rotorua is sited on its southern shore, and the town of Ngongotahā is at the western edge of the lake.

For the lake in the South Island, see Lake Rotorua (Canterbury). For the territorial authority, see Rotorua Lakes.

Lake Rotorua
Location	Rotorua Lakes, Bay of Plenty Region, North Island
Coordinates	38°05′S 176°16′E
Type	crater lake
Primary inflows	Utuhina, Hamurana Spring, Ngongotahā
Primary outflows	Ohau Channel
Basin countries	New Zealand
Max. length	12.1 kilometres (7.5 mi)[1]
Max. width	9.7 kilometres (6.0 mi)[1]
Surface area	79.8 square kilometres (30.8 sq mi)[1]
Average depth	10 metres (33 ft)[1]
Max. depth	45 metres (148 ft)[1]
Surface elevation	280 metres (920 ft)[1]
Islands	Mokoia Island
Settlements	Rotorua, Ngongotahā
References	[1]

The lake was formed from the crater of a large volcano in the Taupo Volcanic Zone. Its last major eruption was about 240,000 years ago. After the eruption, the magma chamber underneath the volcano collapsed. The circular depression left behind is the Rotorua Caldera, which is the site of the lake. Several other lakes of volcanic origin are located nearby to the east, around the base of the active volcano Mount Tarawera.

Lake Rotorua is fed with water from a number of rivers and streams; some such as the Utuhina flow water of a water temperature warmer than the lake due to the thermal activity in the Rotorua area. Conversely streams on the northern shore such as the Hamurana Spring and the Awahou stream flow crystal clear water that has a constant temperature of 10 degrees Celsius. Other notable tributaries include the Ngongotahā stream, famous for trout fishing.

Despite the large volume of water flowing through Lake Rotorua its shallow depth makes it very prone to discolouration, especially from sediment following windy weather. It is well used by fishermen, but less popular with watersports participants and swimmers.

Lake Rotorua

Lake Rotorua flows directly into Lake Rotoiti via the Ohau Channel at the north eastern corner of the lake; this channel is navigable by boat and is also favoured by fly fishermen. The Ohau channel joins at the Mourea delta, an area with very low water levels. This area is frequented by novice kayakers and swimmers. Nearby is the ancestral land of the Ngati Pikiao hapu of the Te Arawa tribe. From Lake Rotoiti the waters of Lake Rotorua flow to the Kaituna River into the Pacific Ocean near Maketu; the rapid descent from over 900 feet above sea level in less than 20 km has created an area used for extreme kayaking and white water rafting.

Mokoia Island, close to the centre of the lake, is a rhyolite dome. It is probably New Zealand's best-known lake island, and is closely associated with one of the best-known Māori legends, that of Hinemoa and Tutanekai. Is said that Hinemoa swam across the lake to her lover Tutanekai who lived on Mokoia Island.

Owing to the geothermal activity around the lake (including still active geysers and hot mud pools), the lake has a high sulphur content. This gives the lake's waters an unusual yellowish-green hue.

Panoramic view of Lake Rotorua from Mount Ngongotahā

Lake Rotorua from the air

See also

• Lakes of New Zealand
• List of lakes in New Zealand

References

1. Lowe, D.J., Green, J.D. (1987). Viner, A.B. (ed.). Inland waters of New Zealand. Wellington: DSIR Science Information Publishing Centre. pp. 471–474. ISBN 0-477-06799-9.CS1 maint: multiple names: authors list (link)