Lake Manapouri

Lake Manapouri
Name	Lake Manapouri
Location	Fiordland National Park, Southland, New Zealand
Type	Glacial lake
Basin countries	New Zealand
Area	142 km2
Max-depth	444 m
Elevation	178 m

Lake Manapouri is a deep glacial lake in Fiordland National Park on the South Island of New Zealand. Renowned for its clear waters and rugged setting amid Southern Alps foothills, it forms part of an interconnected system with Lake Te Anau and feeds the Waiau River. The lake and surrounding landscape have been central to landmark conservation efforts, large-scale hydroelectric projects, and ongoing debates involving indigenous rights and environmental stewardship.

Geography

The lake lies within Fiordland, near settlements such as Te Anau and Manapouri township, and sits downstream of the Kepler Mire and adjacent to Dusky Sound catchments. Surrounded by ranges including the Moa Ridge and peaks associated with the Southern Alps, its shorelines abut protected areas administered by Department of Conservation and are accessed via roads connected to State Highway 94. Proximate landmarks include Milford Sound / Piopiotahi, Doubtful Sound / Patea, Lake Monowai, and Lake Hauroko, with aerial approaches often routed from Queenstown and Invercargill.

Geological formation and hydrology

Carved by Pleistocene glaciation from ice flows tied to the Last Glacial Maximum, the lake occupies a deep over-deepened basin similar to fjord-lakes such as Lake Wakatipu and Lake Taupō in morphology. Bedrock comprises schist and greywacke related to the Haast Schist and terranes of the Pacific Plate subduction margin, influenced by tectonics of the Alpine Fault. Hydrologically, inflows include rivers and streams sourced from catchments near Kepler Mountains and the lake drains via the Waiau River through hydroelectric intakes to the Manapouri Power Station system connected to the West Arm tailrace and ultimately out to Doubtful Sound / Patea fjord. The lake’s maximum depth exceeds many lakes, rivaling depths of Lake Hauroko and exhibiting meromictic tendencies in places documented by hydrographic surveys by institutions such as the National Institute of Water and Atmospheric Research.

Ecology and wildlife

The lake supports oligotrophic aquatic communities with native fish such as New Zealand longfin eel and species linked to the galaxiids family, alongside introduced trout species connected to angling traditions tied to New Zealand Angling & Casting Association history. Surrounding forests of rimu, southern beech, and podocarp assemblages sustain birdlife including kea, kea populations in alpine areas, tūī, bellbird, kiwi and seabirds visiting nearby fiords such as Takahē refugia and mōhua in adjacent conservation zones. Aquatic invertebrates and endemic algae assemblages have been subjects of research by Victoria University of Wellington and University of Otago limnologists, while invasive pests and pathogens have prompted biosecurity initiatives led by MPI and regional councils.

Human history and Māori significance

The lake and its environs are within rohe associated with iwi including Ngāi Tahu and earlier associations with hapū linked to Te Anau seasonal pathways. Māori utilized the lake for mahinga kai, harvesting tuna, waterfowl, and plants; oral histories reference travel routes between inland basins and the Te Waipounamu coastline, with cultural landscapes recorded by scholars at Canterbury Museum and tribal authorities. European exploration and settlement connected the lake to figures such as Thomas Mackenzie-era explorers and early surveyors tied to the development of Southland pastoral stations, with later tourism and hydroelectric interest involving companies such as Meridian Energy and state agencies including Ministry of Works.

Hydro-electric development and the Save Manapouri campaign

The lake became central to national debate when plans for a major hydroelectric scheme to supply the Tiwai Point Aluminium Smelter prompted proposals to raise lake levels, involving the then Hydro-Electric Department (New Zealand) and later advocacy by environmental groups like the Forest & Bird. The resulting public movement, the Save Manapouri campaign, united conservationists, politicians, and cultural leaders including figures linked to Arthur Barnett-era philanthropy, and influenced policy by governments such as administrations led by Norman Kirk and later cabinets. The compromise produced the current Manapouri Power Station design with underground generators in the West Arm and legal instruments overseen by entities including the Waitangi Tribunal and statutory arrangements with Te Rūnanga o Ngāi Tahu, while industrial clients like NZAS at Tiwai Point remain key stakeholders.

Recreation and tourism

Tourism operators from Te Anau and cruise services in Doubtful Sound / Patea run boat trips, hiking routes on the Kepler Track and access to the Milford Track region, with lodges and outfitters based in Te Anau, Queenstown, and Invercargill. Activities include boating, freshwater angling regulated by Fish & Game New Zealand, kayaking, ecological tours guided by operators linked to Heritage New Zealand-listed sites, and scenic flights operated from Queenstown Airport and Te Anau Airport. The area features accommodations ranging from DOC huts on the Kepler Track to boutique lodges promoted by regional tourism agencies including Destination Fiordland.

Environmental management and conservation

Conservation management involves partnerships among DOC, Te Rūnanga o Ngāi Tahu, regional authorities such as Southland Regional Council, and research bodies including National Institute of Water and Atmospheric Research and universities. Management targets include invasive species control led by Predator Free New Zealand initiatives, riparian restoration funded via Environment Southland, and water quality monitoring under frameworks influenced by statutes administered by MfE. Heritage protection and visitor impact mitigation coordinate with international frameworks referenced by UNESCO for nearby protected areas, while adaptive management addresses climate change scenarios investigated by NIWA and modelling groups at University of Canterbury.

Category:Lakes of Fiordland Category:Protected areas of Southland, New Zealand