Lake Manapouri
Lake Manapouri | |
---|---|
Manapōuri ( Waiau River | |
Catchment area | 1,388 km2 (536 sq mi) |
Basin countries | New Zealand |
Max. length | 28 km (17 mi) |
Surface area | 142 km2 (55 sq mi) |
Average depth | 149 m (489 ft) |
Max. depth | 444 m (1,457 ft) |
Water volume | 21.16 km3 (5.08 cu mi) |
Shore length1 | 170 km (110 mi) |
Surface elevation | 177.8 m (583 ft) |
Islands | 33 |
Settlements | Manapouri |
1 Shore length is not a well-defined measure. |
Lake Manapouri (Māori: Manapōuri)[1][2] is located in the South Island of New Zealand.[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]
Māori History
According to
Geography
Lake Manapouri was formed by
The
Lake Manapouri is often described as New Zealand’s most beautiful lake.[3][9]
Biodiversity
The area is well renowned for its fishing and high water quality.[9] Both Lake Manapouri and Lake Te Anau lie within the ultra-oligotrophic index on the trophic state index with clear highly oxygenated waters of very low biological productivity.[9] Both lakes along with the connecting Waiau River contain the New Zealand longfin eel and introduced brown trout and rainbow trout as well as some Atlantic salmon.[9] The area is however free from macrophyte Lagarosiphon major an exotic and invasive species which has infiltrated many other New Zealand lakes.[9]
Lake Manapouri provides 73% of New Zealand’s longfin eel lake habitat protected from commercial fishing.
Submerged vegetation within Lake Manapouri is mostly native species.[10] Lake Manapouri has a high diversity of submerged vegetation.[10] The rare Hydatella inconspicua an endemic shallow water plant was found in many of the Fiordland lakes including Lake Manapouri in 1998, this was the first reporting of it being in the South Island.[10] The finding meant that the plant was no longer considered endangered.[10]
Surroundings
The shoreline in the North and West of the lake remains substantially unaltered since
The islands around Lake Manapouri are of varying size and isolation.[8] Many of the islands contain virtually unmodified vegetation.[8] However, there is large diversity between islands in habitat biodiversity, with some islands being completely devoid of plants and soil and other rich in both.[8] There is confusion as to some differences with some researchers finding that the area of an island plays a role in species richness[13] with others find no correlation at all.[8] Red deer have greatly modified much of Fiordlands' vegetation[9] however only the two largest islands within Lake Manapouri contain introduced red deer while other islands are only occasionally visited by deer.[8] The smaller islands around Lake Manapouri are extremely unusual as they contain natural vegetation which has not been harmed by red deer, as the red deer have not been able to reach the islands.[9] On these islands palatable plants as well as deep moss mat on the forest floor persist under the dense understory layers of the forest.[9]
The Australian brush-tail possum (
Hydro-power from the lake
The lake provides hydro-electric power via the
The water pumped through the station is discharged into Doubtful Sound, accounting for 41 percent of the fresh water consumed in New Zealand in 2010.[16] In 2002, the Government - under pressure from the environmental movement - rejected an application of a business, Southland Water 2000, to bottle 40,000 cubic metres of water in 20 hours, twelve times a year, before the water from the power station is released into Doubtful Sound.[17]
Integrated management of the lake
The environmental movement of Save Manapouri campaign is considered to be the first environmental movement in New Zealand.[9] When this movement won the campaign to stop levels on the lake being raised, the government formed the Guardians of Lake Manapouri and Te Anau.[9] This meant that main campaigners during the Save Manapouri campaign were appointed to advise the managers of the hydro-electric power plant on the management of both Lake Manapouri and Lake Te Anau.[9] This holistic management between nature conservation and hydro-electric development was unprecedented in New Zealand.[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”.[7] The guardians were entitled to reports from the Government on actions that had been taken that were deemed relevant so they could fulfil their jobs.[9]
Defining the natural variation of lake levels was considered very important.[9] The lake had already experienced slumping due to a lowered lake level.[9] Also the forest that surrounded the lake was reliant on a variation of water levels.[9] Shoreline beech forest extended almost 3m below the highest natural lake level.[9] The roots of this forest could be submerged for a maximum of 50 days meaning that lake levels needed to be maintained within a range that did not exceed this maximum.[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.[9]
Lake management guidelines were devised from geomorphological and ecological studies correlated with a 37-year lake level record.[7] The concepts of High, Main and Low Operating Ranges were developed as a basis for management guidelines.[7] The guidelines were verified in practice and incorporated into legislation in 1981.[7] In 1987 the groundings for the Resource Management Act 1991 were being laid.[7] The Government decided that all empowering legislation for hydro-electric stations should be re-issued.[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] Lake management guidelines and shoreline monitoring were formalised under resource consents.[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.[7] Compensation was also granted for a range of adverse environmental effects associated with the diverting of water through the power station.[7]
The Guardians of the Lake were given legal status in the 1990 amendment to the Conservation Act 1987 with additional and similar responsibility for Lake Monowai.[9] The guardians are still active in 2012 and working alongside Meridian Energy, the current owner of the Lake Manapouri Hydroelectric Power Station.[18]
See also
- List of lakes in New Zealand
- Lakes of New Zealand
- Manapouri Hydroelectric Power Station
- Department of Conservation (New Zealand)
- Save Manapouri campaign
References
- ^ Tau, Te Maire (8 February 2005). "Ngāi Tahu - Ngāi Tahu and Waitaha". Te Ara - the Encyclopedia of New Zealand. Retrieved 13 November 2023.
- ^ "Manapouri | Southland, New Zealand". southlandnz.com. Retrieved 13 November 2023.
- ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa Peat, N. (1994). Manapouri Saved: New Zealand's first Great Conservation Success Story. Longacre Press.
- ^ Johnson, A. (1997). "Te Wahipounamu: New Zealand's pristine wilderness". The UNESCO Courier. 4: 40.
- ^ "Power From Manapouri" (PDF). 1967. p. 9. Retrieved 31 August 2021.
- .
- ^ a b c d e f g h i j k l Mark, A.F (2001). "Integrating Nature Conservation with Hydro-Electric Development of Lakes Manapouri and Te Anau, New Zealand: an exercise in complexity". Complexity International. 8.
- ^ JSTOR 2844881.
- ^ .
- ^ .
- ^ S2CID 23118066.
- ^ a b c d e f g h i j Pickrill, R.A (1985). "Beach Changes on Low Energy Lake Shorelines, Lake Manapouri and Te Anau, New Zealand". Journal of Coastal Research. 1 (4): 353–363.
- JSTOR 2407089.
- ^ a b Michael Fallow (29 February 2020). "The genesis of the Guardians". Stuff. Retrieved 31 August 2021.
- ^ White, Mike (30 June 2019). "Saving Manapōuri: The campaign that changed a nation". North & South. Archived from the original on 11 February 2020.
- ^ Dan Hutchinson, "Manapouri NZ's biggest water consumer", 8 December 2010, https://www.stuff.co.nz/southland-times/news/4433869/Manapouri-NZs-biggest-water-consumer
- ^ NZ Herald, "Fiordland water export scheme rejected", 8 April 2002, https://www.nzherald.co.nz/nz/fiordland-water-export-scheme-rejected/XQINOW24PDBE7BND7LXUXE4OUQ/
- ^ "Meridian Energy Annual Report for the year ended 30 June 2009" (PDF). Archived from the original (PDF) on 22 April 2012. Retrieved 30 May 2012.