Lake Ōkāreka (also spelled Okareka, Ōkareka and just termed ) is one of four small lakes lying between Lake Rotorua and Lake Tarawera, in the Bay of Plenty Region of New Zealand's North Island. The others are Lake Rotokākahi (Green Lake), Lake Tikitapu (Blue Lake), and Lake Ōkataina. All lie within the Ōkataina Caldera, along its western edge.

Geography

The lake has a circumference of and with an autumn mean lake level of , About in all, flows from Lake Ōkareka's catchment into Lake Tarawera.

Geology

The lake is closely related to the Ōkareka Embayment on the western margins of the Ōkataina Caldera. Likely formative and modifying eruptions were the Te Rere rhyolite eruption of 25,171 ± 964 years BP and the Rotorua eruption of 15,635 ± 412 cal.yr BP. It was first described in print by Sir George Grey, who visited it on the course of his travels through Rotorua to Taupō in 1849–1850. The route from Ohinemutu to Tarawera was a track which skirted the shore of Ōkāreka and reached the large lake, near the mission station called Galilei. Grey's journal reads:

Grey is also presumed to have introduced Dama Wallaby to the area around Ōkāreka, where they presently still pose a problem.

The shores of Ōkāreka were a scene of Māori life. Cultivations along the lake were common, and Māori fished the waters for whitebait, koura crayfish and toitoi, which were common species in Lake Ōkāreka before Brown trout was introduced. In the 1860s, Alfred Domett visited Ōkāreka and Tarawera, following a similar path to the one that Grey took.

Known for its natural environment, this lake has an adjacent settlement of approximately 600 people. The lake is accessible from the tourist location of Rotorua. The forest nearby to Lake Ōkāreka extends to the western side of Lake Ōkataina and the Whakapoungakau Range.

Pollution

Lake Ōkāreka has reasonably clear, clean water and is used extensively for recreation such as boating, swimming and fishing. However, the quality of the water has been declining over recent years due to excess levels of nitrogen and phosphorus. These nutrients come from surrounding farmland, residential septic tanks and from the release of existing and accumulated nutrients from sediments on the lake bed.

The Lake Ōkāreka Catchment Management Plan was developed in 2004. This is a long-term plan to improve the water quality of the

lake, through changes like sewage reticulation, in-lake chemical treatment and farm nutrient management. It has been calculated that

the load nutrients needed to reach the target TLI of 3.0 are 2.5 tonnes per year of nitrogen and 0.08 tonnes per year of phosphorus.

The trophic level index (TLI) is an overall indication of lake health based on a number of different criteria, values represent a three-yearly average. Better quality sites have a lower TLI. The three-yearly average for Ōkāreka indicates little change over the last five years, being 3.3 in 2014. It had an estimated population of as of with a population density of people per km<sup>2</sup>. Lake Okareka township is part of the larger Kaingaroa-Whakarewarewa statistical area.

Lake Okāreka had a population of 462 in the 2023 New Zealand census, a decrease of 48 people (−9.4%) since the 2018 census, and a decrease of 72 people (−13.5%) since the 2013 census. There were 231 males, 228 females, and 3 people of other genders in 192 dwellings. 2.6% of people identified as LGBTIQ+. The median age was 49.8 years (compared with 38.1 years nationally). There were 69 people (14.9%) aged under 15 years, 66 (14.3%) aged 15 to 29, 231 (50.0%) aged 30 to 64, and 99 (21.4%) aged 65 or older.

See also

  • Lakes of New Zealand

References

  • Environment Bay of Plenty – Regional Council page
  • Lake Okareka Ratepayers' & Residents' Association