[3] The lake is situated within the Fiordland National Park and the wider region of Te Wahipounamu South West New Zealand World Heritage Area.

[4] According to Māori legend Lake Manapouri was created by the tears of two sisters, Moturua and Koronae, who were daughters of an old chief in the region.

[3] Māori have a long history in the area, finding the lake and its surroundings offering an abundance of food in the form of eels and birds such as pigeon and Kākā (forest parrot).

[3] Lake Manapouri drains a large catchment area of 1,388 square kilometres (536 sq mi).

[9] Water levels in the lake are predominantly high during spring due to snow melt and low in winter.

[9] The area is however free from macrophyte Lagarosiphon major an exotic and invasive species which has infiltrated many other New Zealand lakes.

[11] A vertical slot fish pass was installed in 1999 and trap and transfer of elvers (young eels) was started in summer 1998/1999.

[11] Catch totals in the trap and transfer system can vary in correspondence to surface water temperatures falling below 15 °C (288 K).

[12] The shape of the lake funnels wind and waves down the long axis which leads to longshore transport or littoral drift of sediment and size selective sorting.

[12] The short fetch length produces a narrow range of wave conditions and this low energy limits the size of sediment in transport.

[3] In 1959 Consolidated Zinc, with the support of the New Zealand government, planned to raise the lake by up to 30 metres (98 ft) for an increase in power generation for the development of an aluminium smelter.

[3] This resulted in a strong nationwide protest, the Save Manapouri campaign, lasting over a decade, which prevented the raising of the lake from taking place.

[3] The Save Manapouri campaign is regarded as a major milestone in the history of New Zealand's environmental protection.

[9] The group was to “report and make recommendations of Government… on any matter arising from the environmental, ecological and social effects of the construction and operation of the Manapouri-Te Anau electric power scheme on the townships of Manapouri and Te Anau, the lakes and shorelines of Te Anau and Manapouri, and the rivers flowing in and out of these lakes with particular reference to the effects of lake levels on scenic values, conservation, recreation, tourism and other related activities and amenities”.

[9] The raising of the lake levels too high also had the potential to submerge low-lying islands, many of which contained natural vegetation unharmed by red deer.

[7] For Lake Manapouri this meant a public process was established whereby a working party was formed to examine and resolve a wide range of environmental issues.

[7] Also included in the consents was the creation of regulation patterns through the Te Anau and Manapouri control structures to follow more closely to the natural fluctuations of the Waiau River.

[7] The resource consent set up legislation which could restore biological and recreational values to the lower river, particularly the section immediately below the dam.

[9] The guardians are still active in 2012 and working alongside Meridian Energy, the current owner of the Lake Manapouri Hydroelectric Power Station.