Manawatū River
The Manawatū River, 160 km long, rises on the eastern (Hawke’s Bay) slopes of the Ruahine Range. Downstream 50 km it enters the region through the Manawatū Gorge. The name Manawatū is attributed to the explorer Haunui-a-Nanaia, from a place where he took breath and tripped: manawa (heart), tatu (stumble).
Below the gorge the river passed through forested country to just beyond Ōpiki. Here it joined with the Ōroua, its major western tributary. Then it wended towards the sea, past the Makerua and Taonui swamps, and stands of tawa and kahikatea, and along the southern side of the great Moutoa swamp, forming an estuary in the dune-land.
Māori settlements were located along the river’s lower reaches. The swamps, and lakes and streams along the coast, provided eels, the sea provided kahawai, snapper and sharks. Thousands of kererū (pigeons) fed in the forest, and taro (an edible starchy plant) grew on coastal flats.
Forest clearing west of the ranges began in earnest in the 1870s. Since 1880 the Manawatū River system has flooded many times. The largest floods were in 1880, 1897, 1902, 1907, 1941, 1953, 1965, 1992 and 2004.
Taming the river
Early European settlers began substantial swamp drainage. So did investors in flax, which could be harvested successfully from newly drained land. When the flax industry bottomed out, the land was drained further and turned over to farming in Makerua, and later in Moutoa and Whirokino. In 1942 a new channel, from Whirokino to the ocean, turned the big bend at Foxton into a bywater.
Make a lake
Palmerston North is the only New Zealand city without a stretch of water large enough for regattas and other competitions. A local campaign, Project Lake Manawatū, advocates the creation of a watersports and recreational lake alongside the Manawatū River.
Stopbanks in Ōpiki and Makerua in the early 1920s created greater problems for other areas. This continued until 1962, when the Moutoa channel and sluice gates were built. Up to 2,450 cubic metres per second of water could be diverted, leaving the existing river channel to cope with 1,274 cubic metres per second – a total bigger than any recorded water flow of the river to date. Between 1961 and 2014 the sluice gates were opened 41 times.
The Lower Manawatū Scheme is one of the largest and most complex systems of flood protection measures in New Zealand, with 250 kilometres of stopbanking protecting 320 square kilometres of pastoral, horticultural and urban land. About 20% of Palmerston North relies on the stopbanks to prevent flooding from the Manawatū River.
The February 2004 flood was larger than all floods since 1902, and presented a major challenge to the flood protection scheme. A number of stopbank failures led to 25% of the protected area being flooded. After 2004 two major upgrade projects commenced.
Manawatū Gorge
6-km gorge known also as Te Āpiti (the narrowing). It is the most dramatic feature of the region. It was also known as Te Aurere-a-te-tonga, and a great red rock as Te Ahu-o-Tūranga.
The Rangitāne people say that the gorge was formed when the giant tōtara tree Ōkatia forced its way through the Ruahine and Tararua ranges. The geological explanation is equally dramatic: the river kept to its course as the land uplifted to form the ranges.
A sublime sight
An early settler described first seeing the Manawatū River: ‘The valley in which it flows is narrow, and the steep hillsides on either side are thickly clad with forest . . . A blue haze, like that of the Blue Mountains, shrouds all the distance. The trees are hoary with mosses, hidden and smothered with creepers … the wall of rock on the left rises sheer from the road. Beneath whirls and foams the river in its rocky bed.’ 1
The mountain ridges here are well below their maximum altitude of over 1,700 m in the Ruahine Range and over 1,500 m in the Tararua Range. Even the summits are in pasture. The course of the river itself through the gorge, at under 100 m above sea level, is in places 200 m below the surrounding heights. On cold mornings the gorge is blanketed in fog.
The gorge was a challenge to the colonists. They completed a road in 1871, a bridge in 1875, and a railway in 1891.
The road through the gorge is still perilous, and was closed for 75 days after the massive flooding in February 2004. But it is a vital part of the region’s road and rail network.
