|Length||180 km (110 mi)|
|- average||102 m3/s (3,600 cu ft/s)|
The Manawatu River, often spelled Manawatū in New Zealand English, is a major river of the lower North Island of New Zealand.
The river has its headwaters to the northwest of Norsewood in the Ruahine Ranges of the Tararua District. It flows initially eastward before turning south-west near Ormondville, flowing 40 kilometres (25 mi) before turning north-west near Woodville. At this point the river enters the Manawatu Gorge. Beyond the gorge it again turns south-west, flowing through the city of Palmerston North, and finally becomes the Manawatu Estuary as it enters the Tasman Sea at Foxton Beach.
The river, along with the more northern Whanganui River, gives its name to the Manawatu-Whanganui region. The name of the river was given by the tohunga Haupipi-a-Nanaia, a descendant of Haunui-a-paparangi. Haupipi-a-Nanaia or Hau, travelled down the west coast in pursuit of his wife Wairaka, who had eloped. When Hau reached what is now known as the Manawatū River, he is said to have stopped and clutched his chest, horrified at the prospect of crossing so mighty an expanse of water. Therefore the river's name comes from the Māori words manawa (heart) and tū (stand still). In this context, when said together, the interpretation is ‘heart standing still’ to represent how Hau felt when he first saw the river. However cross he did, and a few kilometres south of Paekakariki, Hau overtook the fugitives and changed Wairaka into a rock.
The river is unique among New Zealand rivers, starting on the east side of the main dividing range and having its outflow to the west. The explanation for this is the uplift of the central ranges. The ranges moved upwards at the same time as the gorge was eroded by the river, instead of the more usual erosion of an already existing range. This suggests that the river is an old one, as it must have existed before the Ruahine and Tararua Ranges.
Major tributaries of the river include the Makakahi, Mangahao, Pohangina and Oroua Rivers. The Manawatu's total length is 180 kilometres (110 mi), making it only the 12th-longest in the country, but at 102 cubic metres per second (3,600 cu ft/s) it is one of the country's greatest rivers in terms of flow, and second only to the Waikato River among North Island rivers.
The Manawatu River flooded in February 2004, displacing over 3000 people (primarily from Marton and Feilding) and damaging over 1000 Manawatu farms. The cost of the flood in terms of insurance payouts was NZ$122 million. Further damage was prevented by the opening of the Moutoa floodgates, which intercept the river between Foxton and Shannon.
In 2018 a case study on water quality in the Manawatū-Whanganui Region was jointly commissioned by Horizons Regional Council and the Ministry for the Environment, the study was conducted by Land Water People (LWP) and the results were reviewed by the National Institute of Water and Atmospheric Research (NIWA) and StatsNZ. Results showed that water quality for sediment and E. coli have improved over the past 7-10 years in the Manawatu-Whanganui region. The report found strong statistical evidence of a connection between regional scale water quality improvements and local scale interventions.
In 2006 Fonterra were criticised for an application to discharge 8,500 cubic metres (300,000 cu ft) of wastewater into the Manawatu River. In 2009, the Cawthron Institute found that the river had the highest gross primary production (GPP) compared to 300 rivers and streams in the Western world. High GPP rates are an indication of poor ecological health and can lead to various environmental issues. In 2011, the Horizons Regional Council laid blame with the Palmerston North City Council for "considerable" and "sustained" breaches of one of its discharge consents, and some degree of non-compliance with two others. A report by the Ministry for the Environment ranked 76 New Zealand sites for water clarity and E. coli levels. Using those measures, they found four other New Zealand rivers rate worse than the Manawatu (the Waitara, Whanganui, Waipa and Rangitikei).
- Reed, A.W. (1996) The Reed Dictionary of Māori Place Names, Te Papakupu Ingoa Wāhi Māori a Reed (3rd Ed) Reed Publishing: Auckland, New Zealand
- Snelder, Ton. "Assessment of recent reductions in E. coli and sediment in rivers of the Manawatū-Whanganui Region". Land Water People Ltd. Retrieved 22 November 2018.
- "Forest & Bird calls on Fonterra to clean up its act on the Manawatu River" (Press release). Royal Forest and Bird Protection Society of New Zealand. 9 August 2006. Retrieved 13 March 2008.
- Young, Roger. "Ecosystem metabolism in the Manawatu River". Cawthron Institute. Retrieved 15 May 2011.
- "Manawatu River pollution blamed on council". Fairfax NZ. Retrieved 14 April 2012.
- "Recreational river water quality league table: water clarity and Escherichia coli bacteria levels". Ministry for the Environment. Retrieved 26 November 2009.
- Knight, Catherine (2016). New Zealand's Rivers: An Environmental History. Christchurch: Canterbury University Press. ISBN 978-1-927145-76-0.
- Knight, Catherine (2014). Ravaged Beauty: An Environmental History of the Manawatu. Auckland: Dunmore Press. ISBN 978-1-927212-13-4.
|Wikimedia Commons has media related to Manawatu River.|
- State of New Zealand's Environment 1997 - Chapter 7: Nature of NZ's water environment [Ministry for the Environment]