Manawatū River
   HOME

TheInfoList



OR:

The Manawatū River is a major river of the lower
North Island The North Island ( , 'the fish of Māui', historically New Ulster) is one of the two main islands of New Zealand, islands of New Zealand, separated from the larger but less populous South Island by Cook Strait. With an area of , it is the List ...
of New Zealand. The river flows from the
Ruahine Ranges The Ruahine Range is the largest of several mountain ranges in the North Island of New Zealand that form a ridge running parallel with the east coast of the island between East Cape and Wellington. The ridge is at its most pronounced from the ce ...
, through both the
Manawatū Gorge The Manawatū Gorge () is a steep-sided gorge formed by the Manawatū River in the North Island of New Zealand. At long, the Manawatū Gorge divides the Ruahine and Tararua Ranges, linking the Manawatū and Tararua Districts. It lies to the ...
and the city of
Palmerston North Palmerston North (; , colloquially known as Palmerston or Palmy) is a city in the North Island of New Zealand and the seat of the Manawatū-Whanganui region. Located in the eastern Manawatū Plains, the city is near the north bank of the Manaw ...
, and across the Manawatū Plains to the Tasman Sea at Foxton.


Name

The river, along with the more northern
Whanganui River The Whanganui River is a major river in the North Island of New Zealand. It is the country's third-longest river, and has special status owing to its importance to the region's Māori people. In March 2017 it became the world's second natur ...
, gives its name to the Manawatū-Whanganui region. The name of the river was given by the
tohunga In the culture of the Māori people, Māori of New Zealand, a tohunga (tōhuka in Southern Māori dialect) is an expert practitioner of any skill or art, either religious or otherwise. Tohunga include expert priests, healers, navigators, carvers, ...
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 Paekākāriki, Hau overtook the fugitives and changed Wairaka into a rock.


Geography

The Manawatū River has its headwaters northwest of Norsewood in the
Tararua District The Tararua District is a Districts of New Zealand, district near the south-east corner of New Zealand's North Island that is administered by the Tararua District Council. It has a population of and an area of 4,364.62 km². The district' ...
, on the eastern slopes of the
Ruahine Range The Ruahine Range is the largest of several mountain ranges in the North Island of New Zealand that form a ridge running parallel with the east coast of the island between East Cape and Wellington. The ridge is at its most pronounced from the ce ...
on the North Island of New Zealand. It flows initially eastward before turning south-west near
Ormondville Ormondville is a locality in the Manawatū-Whanganui region of New Zealand's North Island. It is located inland, south of Waipukurau and west of Flemington, Hawke's Bay, Flemington, Hawke's Bay Region, Hawke's Bay. Ormondville railway station ...
, flowing before turning north-west near Woodville. At this point it enters the
Manawatū Gorge The Manawatū Gorge () is a steep-sided gorge formed by the Manawatū River in the North Island of New Zealand. At long, the Manawatū Gorge divides the Ruahine and Tararua Ranges, linking the Manawatū and Tararua Districts. It lies to the ...
, between the Ruahine and
Tararua Range The Tararua Range, often referred to as the Tararua Ranges or Tararua, is one of several mountain ranges in the North Island of New Zealand. The Tararua Range runs northeast–southwest for from near Palmerston North to the upper reaches of ...
s. Beyond the gorge it joins with the Pohangina River at
Ashhurst Ashhurst ( - Raukawa is an aromatic plant used to make scent) is a town and outlying suburb of Palmerston North, in the Manawatū-Whanganui region of New Zealand's North Island. Location Ashhurst is sited 14 kilometres northeast of the ...
and turns south-west, flowing through the city of
Palmerston North Palmerston North (; , colloquially known as Palmerston or Palmy) is a city in the North Island of New Zealand and the seat of the Manawatū-Whanganui region. Located in the eastern Manawatū Plains, the city is near the north bank of the Manaw ...
. At this stage the river is still flowing swiftly and carrying gravel from the mountains. After Opiki, it slows and has a lower gradient,
meander A meander is one of a series of regular sinuous curves in the Channel (geography), channel of a river or other watercourse. It is produced as a watercourse erosion, erodes the sediments of an outer, concave bank (cut bank, cut bank or river cl ...
ing over the Manawatū Plains; its bed at this point is mud and silty sand. In its meandering and frequent shifting of course it has created
oxbow lake An oxbow lake is a U-shaped lake or stream pool, pool that forms when a wide meander of a river is meander cutoff, cut off, creating a free-standing body of water. The word "oxbow" can also refer to a U-shaped bend in a river or stream, whether ...
s,
lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') an ...
s, and
swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...
s. Sediment deposited along its course has created levees, higher than the surrounding plain; when the river is in flood it overflows these and creates wetlands. The Manawatū reaches the
Tasman Sea The Tasman Sea is a marginal sea of the South Pacific Ocean, situated between Australia and New Zealand. It measures about across and about from north to south. The sea was named after the Dutch explorer Abel Janszoon Tasman, who in 1642 wa ...
at
Foxton Beach Foxton Beach is a small settlement in the Horowhenua District of the Manawatū-Whanganui region of New Zealand's North Island. It is located on the South Taranaki Bight at the mouth of the Manawatū River, 35 kilometres southwest of Palmers ...
, on the west coast of the North Island, creating the Manawatū Estuary. Major tributaries of the river include the Mākākahi, Mangahao, Pohangina and Oroua Rivers. The Manawatū's total length is , making it only the 12th-longest in the country, but at it is one of New Zealand's greatest rivers in terms of flow, and second only to the
Waikato River The Waikato River is the longest river in New Zealand, running for through the North Island. It rises on the eastern slopes of Mount Ruapehu, joining the Tongariro River system and flowing through Lake Taupō, New Zealand's largest lake. It th ...
among North Island rivers.


Bridges

The river is crossed by 18 road bridges (not including the under-construction Parahaki Island Bridge), 3 rail bridges and He Ara Kotahi walk/cycleway. The lowest and longest, Whirokino Trestle and Manawatū River Bridge, carry SH1 over the Moutoa Floodway and over the river. It replaced the 1938 and 1942 bridges in February 2020, at a cost of $70m. The derelect Opiki Toll Bridge crosses the river and no longer has a floor. It is a
Heritage New Zealand Heritage New Zealand Pouhere Taonga (initially the National Historic Places Trust and then, from 1963 to 2014, the New Zealand Historic Places Trust; in ) is a Crown entity that advocates for the protection of Archaeology of New Zealand, ancest ...
Category I historic place.


Geology

The Manawatū is unique among New Zealand rivers in that it crosses a mountain range. The river has formed a "water gap" across the mountains because it is older than the Ruahine and
Tararua Ranges The Tararua Range, often referred to as the Tararua Ranges or Tararua, is one of several mountain ranges in the North Island of New Zealand. The Tararua Range runs northeast–southwest for from near Palmerston North to the upper reaches of ...
. Most rivers arise from an already-existing range of mountains or hills, but beginning about 3 million years ago the central North Island mountain ranges began to uplift across the Manawatū's current course. Because it drained a large catchment, the river had sufficient flow to keep pace with and erode the rising mountains, eventually forming the Manawatū Gorge; other rivers were unable to and were diverted into the Manawatū instead. After exiting the Manawatū Gorge, the river carries rock and sediment down from the mountains. During glacial times, with the prevalence of ice, snow, and bare mountains, this erosion increases and forms a stony elevated terrace. During an interglacial, while the mountains are forested, gravel outwash is reduced and the river cuts down into the terrace, forming a gorge. This cycle has created four distinct terraces between the Manawatū Gorge and Palmerston North. The Manawatū Plain was seabed 5 to 6 million years ago, and as it was raised above water by the action of the Australian and Pacific Plates it buckled, forming five long and low ridges (or
anticline In structural geology, an anticline is a type of Fold (geology), fold that is an arch-like shape and has its oldest Bed (geology), beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex curve, c ...
s) parallel to the mountains, which impede the flow of the Manawatū, Rangitikei, and Oroua Rivers, forcing them to flow southwest rather than directly into the Tasman Sea.


Vegetation

At the time of human arrival, the Manawatū Plains were covered with forest. Towards the foothills and the Manawatū Gorge grew black beech, turning into tawa forest at lower altitudes. Along the plains and terraces the forest was mixed
podocarp Podocarpaceae is a large family of mainly southern hemisphere conifers, known in English as podocarps, comprising about 156 species of evergreen trees and shrubs.James E. Eckenwalder. 2009. ''Conifers of the World''. Portland, Oregon: Timber Pres ...
and
tōtara ''Podocarpus totara'' (), commonly known as the , is a species of Podocarpus, podocarp tree endemism, endemic to New Zealand. It grows throughout the North Island, South Island and rarely on Stewart Island, Stewart Island / Rakiura in lowland, ...
, changing to mixed tawa, tītoki, and māhoe in the sand dunes. Across the flood plain of the Manawatū and on the low-lying land bordering the river, the predominant vegetation was semi-swamp forest, mostly
kahikatea ''Dacrycarpus dacrydioides'', commonly known as kahikatea (from Māori language, Māori) and white pine, is a Pinophyta, coniferous tree endemism, endemic to New Zealand. A Podocarpaceae, podocarp, it is New Zealand's tallest tree, gaining hei ...
and pukatea. Three major swamps bordered the Manawatū: Moutoa Swamp north of the river, towards the mouth, known as the "Great Swamp" in the 19th century; Makerua Swamp further inland, to the south of the Manawatū and north of the Tokomaru River, which covered 22000 acres; and Taonui Swamp on the north side of the river. The main vegetation in the swamps was harakeke and
raupō ''Typha orientalis'', commonly known as bulrush, cumbungi, or raupō, is a perennial herbaceous plant in the genus ''Typha''. It is native to Australia, New Zealand, Malaysia, Indonesia, Japan, Korea, Mongolia, Myanmar, Philippines, China and th ...
: harakeke in the drier parts, raupō in the wetter. The Manawatū river mouth and estuary was listed under the
Ramsar Convention The Ramsar Convention on Wetlands of International Importance Especially as Waterfowl Habitat is an international treaty for the conservation and sustainable use of Ramsar site, Ramsar sites (wetlands). It is also known as the Convention on We ...
as a Wetland of International Importance in 2005.


Flooding

The Manawatū River flooded in February 2004, displacing over 3000 people (primarily from Marton and
Feilding Feilding is a town in the Manawatū District of the North Island of New Zealand. It is located on New Zealand State Highway 54, State Highway 54, 20 kilometres north of Palmerston North. The town is the seat of the Manawatū District Council. ...
) and damaging over 1000 Manawatū 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
floodgate Floodgates, also called stop gates, are adjustable gates used to control water flow in flood barriers, reservoir, river, stream, or levee systems. They may be designed to set spillway crest heights in dams, to adjust flow rates in sluices and ...
s, which intercept the river between Foxton and Shannon.


Water quality

In 2018 a case study on water quality in the Manawatū-Whanganui region was jointly commissioned b
Horizons Regional Council
and the Ministry for the Environment, the study was conducted b
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 Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...
and ''E. coli'' had improved over the previous seven to ten years in the Manawatū-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 of wastewater into the Manawatū River. In 2009, the Cawthron Institute found that the river had the highest
gross primary production In ecology, primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. It principally occurs through the process of photosynthesis, which uses light as its source of energy, but it also occurs through ...
(GPP) compared to 300 rivers and streams in the Western world. High GPP rates are an indication of poor
ecological health Ecological health is a term that has been used in relation to both human health and the condition of the environment. * In medicine, ecological health has been used to refer to multiple chemical sensitivity, which results from exposure to synthet ...
and can lead to various
environmental issue Environmental issues are disruptions in the usual function of ecosystems. Further, these issues can be caused by humans (human impact on the environment) or they can be natural. These issues are considered serious when the ecosystem cannot recov ...
s. 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 ''Escherichia coli'' ( )Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. is a gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escherichia'' that is commonly foun ...
'' levels. Using those measures, they found only four other New Zealand rivers rate worse than the Manawatū (the Waitara,
Whanganui Whanganui, also spelt Wanganui, is a city in the Manawatū-Whanganui region of New Zealand. The city is located on the west coast of the North Island at the mouth of the Whanganui River, New Zealand's longest navigable waterway. Whanganui is ...
, Waipā and Rangitīkei).


References


Sources

* *


External links


State of New Zealand's Environment 1997 - Chapter 7: Nature of NZ's water environment [Ministry for the Environment]
* * {{DEFAULTSORT:Manawatū River Rivers of Manawatū-Whanganui Rivers of New Zealand