Lake Opuha

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Lake Opuha
View of the reservoir looking north-northwest from the road
View of
the reservoir looking north-northwest from the road
Inflows: North Opuha River , South Opuha River and various creeks
drain: Opuha River
Larger towns nearby: fairlie
Lake Opuha (New Zealand)
coordinates 43° 59' 0"  S , 170° 52' 0"  E Coordinates: 43° 59' 0"  S , 170° 52' 0"  E
Building data
lock type: gravity dam
Construction time: 1995 to 1997
Height of the barrier structure : 50 m
crown length: 100 meters
power plant output: 7MW
Operator: Opuhua Water Ltd
Data on the reservoir
Altitude (at storage destination ) 390  m
water surface 710 hadep1
reservoir length 4.2 km
reservoir width 2.8km
Maximum depth 50 m
total storage space : 74 000 000  m³
catchment area 500 km²
Lake Opuha with Island.jpg

View of the lake with its small island from the dam

Lake Opuha is a reservoir in the Canterbury region of the South Island of New Zealand primarily used for irrigation of the surrounding area .

geography

The reservoir is located around 50 km northwest of Timaru and 10 km north of the town of Fairlie and has an area of ​​up to 710  hectares , a length of 4.2 km and a maximum width of 2.8 km. In the southeastern part of the lake there is an island that is 900 m long and up to 300 m wide.

The reservoir is fed by the two rivers North Opuha River and South Opuha River as well as by various creeks that carry the water from the surrounding mountains. Together, the rivers and streams cover a water catchment area of ​​around 500 km 2 . Discharge is via the Opuha River , which branches off to the southeast .

The lake , which has a capacity of more than 74 million m 3 , can be reached from the west and south via four different country roads starting from New Zealand State Highway 79 .

story

Originally, the concept of constructing a dam on the Opuha River arose from discussions between the Electricity Corporation of New Zealand (ECNZ) and the Opihi Augmentation Society . They led to a partnership formed in 1992, which other companies and organizations have joined over the years. The aim of the project was to create a water reservoir for irrigating the agricultural areas in the surrounding area. Work on the dam began in 1995.

dam breach

On February 6, Waitangi Day 1997, three days of rain burst the uncompleted dam and 13 million m 3 of water tumbled down the river. Rapid evacuation efforts prevented any of the more than 200 people killed or injured, but around 1,000 head of cattle lost their lives and damage to the dam totaled NZ$8 million  and around NZ$4 million Damage to farmers downstream of the dam. After the damage had been repaired and the dam finally completed, the structure was officially opened on November 7, 1998.

dam

The 50 m high and around 370 m wide dam made of earth material is able to hold back a water volume of 74 million m 3 (another source states 91 million m 3 here ). On its southwest side, the dam has a 35 m wide spillway and below the dam a small power plant operated with just one generator, which has an output of 7  MW and an annual total output of 25 GWh.

tourism

The reservoir is used in summer for boat and kayak trips and for water skiing . In addition to rainbow trout , which were already resident in the river before the dam was built, the species of trout and salmon that settled in the lake later can be fished.

Water scarcity

The reservoir was created because the region had repeatedly suffered from water shortages. However, when there is little rain, the reservoir can threaten to dry up, as in January 2015, when the lake only had 23% of its possible water volume.

panoramic photo

See also

web links

Commons : Lake Opuha  - Collection of images, videos and audio files

itemizations

  1. ↑ a b c d Topo maps . Land Information New Zealand , accessed 23 January 2020 (English).
  2. ↑ a b c d History of the Dam Project . Opuhua Water Ltd , retrieved 23 January 2020 (English).
  3. ↑ Coordinates and longitude determinations were made using Goggle Earth Pro version 7.3.2.5776 on the 23rd; made January 2020
  4. ↑ John Keast : Opuha Book 'A Dream Fulfilled' . In: The Press . December 1, 2007, accessed January 23, 2020 (English).
  5. ↑ Lake Opuha instrument upgrade safeguards the environment . (PDF; 458; kB) In: NIWA . Retrieved January 23, 2020 (English).
  6. ↑ Power Station Generation . Opuhua Water Ltd , retrieved 23 January 2020 (English).
  7. ↑ Lake Opuha . NZ Fishing , accessed 23 January 2020 (English).
  8. ↑ Lake Opuha could run dry in a month . In: Radio New Zealand . January 18, 2015, retrieved January 23, 2020 (English).