IN my last piece I explored the dynamic and powerful natural forces of the Waioeka River that have shaped our surrounding landscape.
The river has been at the centre of the community since human settlement, and which resulted in it being changed and altered by us.
If we go back in time prior to the arrival of humans in this landscape we can picture a very different landscape from the one we look out on today.
Hollows between dunes surrounding the river mouth collected rainwater and formed small wetlands.
Larger wetlands cloaked with uniquely adapted plants would have formed on flood plains, and moisture-loving trees such as pukatea and kahikatea would have formed a spectacular backdrop.
Rivers and tributaries would have been bounteous with native fish and eels, with wetlands providing a haven to bird numbers we can only imagine today.
Where, today, flood plains are criss-crossed by fences and drains forming paddocks, in the past they would have been thick with native vegetation adapted to regular inundation.
For centuries, Maori have utilised the resources and transport opportunities afforded by this rich landscape.
The name Waioeka (waters of the weka) refers to the abundance of the bird in the vicinity of the river.
Wetlands provided valuable food and building resources, while the river provided waka launching places, suitable sites for eel weirs, and access to fishing.
Tributaries deliniated tribal and hapu boundaries and served as an important transportation network. Habitation was not limited to the coast and estuary, with settlements further upstream.
River waka were fashioned from an appropriate tree, allowing accommodation for up to four persons and their goods. These specialised waka were still being used to travel rivers at the time of European settlement, with a traditional river waka on display at the Whare Taonga, Opotiki Museum.
With the arrival of Europeans and their hunger for “productive” land, the river and its surrounding floodplains became irreversibly altered.
Shallow water wetlands were drained and vegetation cleared through arduous hand labour. Erosion and siltation was a concern from the earliest days of settlement, and riverbanks were reinforced with live and dead willows.
Ironically the valuable service of flood-mitigation provided by lush and extensive wetlands was lost once these wetlands were drained and cleared.
Times of flood turned the river into a raging and violent sediment-laden torrent able to wreak destruction on the town situated on a floodplain between two rivers.
After flooding in 1957 and 1958 local authorities undertook a comprehensive flood protection scheme, which involved willow protection of eroding banks, straightening of meanders, clearance of a floodway, and river training prior to the construction of stopbanks.
These works were well under way when the worst flooding in recorded history struck Opotiki and surrounding areas in 1964, causing the work to be fast-tracked and completion of the flood-protection scheme in 1967.
Alteration of the river was not limited to its lower reaches. A road of sorts joined Opotiki with Gisborne through the Waioeka Gorge by 1929, but travel was arduous over the largely unsealed muddy track fording unbridged streams and subject to frequent landslides during rain. In 1950 the government announced it would upgrade the road, at a then astronomical cost.
One of the most significant engineering challenges was a 50-metre-high bluff that had to be dropped into the river, allowing the river channel itself to be moved by 12 metres and providing a platform for the road to be built on.
In an incredible feat of engineering, bulldozers were lowered down on steel ropes to clear the debris, and it is tragic that three men died during the construction of the road.
From the earliest days of travel through the gorge the road has been plagued by frequent slips due to high rainfall and the underlying geology of the ranges.
The most significant of these was a large slip in 2012 that closed the road for 26 days.
In what may be the beginning of a new chapter in Opotiki’s relationship with the Waioeka River, another planned momentous change will see a permanently open channel to the harbour formed by the river estuary as the waters of the weka make their way to the open sea.
Geology by Llmars Gravis