Rakaia River

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The Rakaia River as viewed from Mount Hutt

The Rakaia River system

The Rakaia River (English: Cholmondeley),^[1] in the Canterbury Plains in New Zealand's South Island, is one of the largest braided rivers in New Zealand .^[2] The river has a mean flow of 203 cubic metres per second and a mean annual seven-day low flow of 87 cubic metres per second. ^[3]

It rises in the Southern Alps, travelling 150 kilometres in a generally easterly or southeasterly direction before entering the Pacific Ocean 50 kilometres south of Christchurch.

For much of its journey, the river is a braided river, running through a wide shingle bed. Close to Mount Hutt, however, it is briefly confined to a narrow canyon known as the Rakaia Gorge.

The two bridges crossing the Rakaia River, at the township of Rakaia, are New Zealand's longest road and rail bridges respectively.^[4] The bridges are some 1750 metres in length. The small town of Rakaia, 20 kilometres from the Rakaia River mouth, is halfway between Christchurch and Ashburton.

The Rakaia River is a celebrated Chinook salmon (Oncorhynchus tshawytscha) fishery.^[5] The Rakaia is known for its large wrybill population which represents 73 percent of the total population. Other important bird species known to be found in the Rakaia riverbed are Wrybill, Black fronted Tern and Banded Dotterel.^[6]

The Central Plains Water Trust is proposing to take up to 40 cumecs of water from the Rakaia River as part of the Central Plains Water enhancement scheme.^[7]

[edit] References

^ Rakaia River, Place Name Detail, New Zealand Geographic Placenames Database, Land Information New Zealand website, retrieved 2 April 2008.
^ Morland, K. 1994: Water Resources of the Canterbury Region. Canterbury Regional Council Unpublished Technical Report U94/59.
^ Morgan, M., Bidwell, V., Bright, J., McIndoe, I, and Robb, C. (2002): "Canterbury Strategic Water Study" Lincoln Environmental Report No 4557/1, Lincoln University, New Zealand. Table 6.1. http://www.ecan.govt.nz/Our+Environment/Water/PlansandReports/StrategicWaterStudy.htm
^ "The Rakaia River", Selwyn District Council, http://www.selwyn.govt.nz/background/rakaia.htm, retrieved 31 August 2007
^ West I. F. and Goode,R. H. (1987) "Aerial counts of spawning chinook salmon {Oncorhynchus tshawytscha) on the Rakaia River system, Canterbury, New Zealand, 1973-76." New Zealand Journal of Marine and Freshwater Research, 1987, Vol. 21: 563-572.
^ O’Donnell, C.F.J. (2000).The significance of river and open water habitats for indigenous birds in Canterbury, New Zealand, Environment Canterbury Unpublished Report U00/37.
^ Central Plains Water Trust applications for resource consent Environment Canterbury Resource Consents webpage, retrieved 6 October 2007.