The Pakoka River is a river of the Waikato Region of New Zealand's

North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-largest ...

. It flows southwest from its source southeast of

Raglan Raglan may refer to: People *FitzRoy Somerset, 1st Baron Raglan (1788–1855), British Army officer, commander of British troops during the Crimean War *Raglan (surname) *Raglan Squire (1912–2004), British architect Places Australia *Count ...

to reach the northeastern end of the Aotea Harbour. The catchment is made up of just over of waterways.

Geology

The most notable features of the Pakoka valley were formed by Upper Pliocene–Lower Pleistocene Okete Volcanics about 2 million years ago. These rocks form the top of the Wharauroa Plateau, where the Pakoka rises. They also flowed down from a vent about a kilometre northwest of

Bridal Veil Falls Bridal Veil Falls, Bridalveil Falls or Bridalveil Fall is a frequently-used name for waterfalls that observers fancy resemble a bride's veil: Australia * Bridal Veil Falls, Leura, in the Blue Mountains National Park, New South Wales * Govetts Le ...

to block the valley and form the falls. From its source the river soon drops about , cutting into Coleman Conglomerate a Puaroan (in the

Tithonian In the geological timescale, the Tithonian is the latest age of the Late Jurassic Epoch and the uppermost stage of the Upper Jurassic Series. It spans the time between 152.1 ± 4 Ma and 145.0 ± 4 Ma (million years ago). It is preceded by the K ...

epoch, about 150 million years ago) poorly sorted

conglomerate Conglomerate or conglomeration may refer to: * Conglomerate (company) * Conglomerate (geology) * Conglomerate (mathematics) In popular culture: * The Conglomerate (American group), a production crew and musical group founded by Busta Rhymes ** Co ...

of sandstone and

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, p ...

, containing andesitic pebbles up to in diameter. A

rock arch A natural arch, natural bridge, or (less commonly) rock arch is a natural landform where an arch has formed with an opening underneath. Natural arches commonly form where inland cliffs, coastal cliffs, fins or stacks are subject to erosion fr ...

and several notable bluffs are formed of late Whaingaroan Ahirau Sandstone formed about 28 million years ago. Although classified as sandstone, it looks more like limestone, with 40-60% calcium carbonate content and lapiez features in massive (lacking internal structures), blue-grey, calcareous, fine sandstone. Apart from recent alluvial deposits, the other main rock in the valley is Hauturu Sandstone, which is mid to late Whaingaroan, about 30 million years old. It is commonly knobbly due to resistant bands and lenses of hard calcareous sandstone in soft friable quartzo feldspathic sand.Geology of the Raglan-Kawhia Area: Institute of Geological & Nuclear Sciences (N.Z.), Barry Clayton Waterhouse, P. J. White 1994

Biota

About two-thirds of the catchment is pasture, with the rest under trees and scrub. Less than 10% of the catchment was fenced from livestock in 2014. New Zealand fernbird and Spotless crake have been recorded in the catchment. A Regional Council study describes the vegetation around the estuary - "Te Heru Point and up towards Pakoka Landing, a forest of akeake, kanuka and kowhai lines the estuary arm. Spartina is present on the ight bankupstream of Ohiawhakainga Creek. Patches of sea meadow are found at the mouth of the Motakotako Creek in front of the rushes. The saline influence on the vegetation finishes just upstream of the road bridge at Pakoka Landing. Moving downstream on the true-left bank are bands of saltmarsh ribbonwood with marsh clubrush and raupo wetland behind. Small patches of seagrass are found on the mud flats around the corner where the river widens out. The farmland is not fenced along the

eft bank A newt is a salamander in the subfamily Pleurodelinae. The terrestrial juvenile phase is called an eft. Unlike other members of the family Salamandridae, newts are semiaquatic, alternating between aquatic and terrestrial habitats. Not all aquat ...

and stock access is potentially a problem. A mature (~10 years?) flowering mangrove is upstream of Karetoto Island. A small patch of saltwater paspalum is found immediately opposite the island. A patch of seagrass lies behind the oyster bank at Mowhiti Point. The harbour edge is lined by a thin band of rush." Mitigation funding from Te Uku Wind Farm and support from farmers and Regional Council have resulted in Whaingaroa Harbour Care putting up 15 km of fencing to protect the river and its tributaries and planting 150,000 trees in the valley above

. This has been followed by a

possum Possum may refer to: Animals * Phalangeriformes, or possums, any of a number of arboreal marsupial species native to Australia, New Guinea, and Sulawesi ** Common brushtail possum (''Trichosurus vulpecula''), a common possum in Australian urban a ...

and rat control project jointly with the

Department of Conservation An environmental ministry is a national or subnational government agency politically responsible for the environment and/or natural resources. Various other names are commonly used to identify such agencies, such as Ministry of the Environment, ...

. Six sites were surveyed for the windfarm and given Stream Health Index scores between 60 and 170.5 (poor to excellent). Their 2006 survey identified these stream quality indicator species in the Pakoka, - the higher the score, the more sensitive these macroinvertebrates are to pollution. The NIWA Freshwater Fish Database shows the Pakoka has longfin eel, koura, Cran's Bully (''Gobiomorphus basalis'') and redfin bully, banded kokopu and smelt.

Bridges

The Pakoka is bridged by Plateau Road, Kawhia Road and Te Papatapu Road, which is the lowest bridge, being alongside Pakoka Landing. That lowest bridge was opened in 1922 and seems to have been used by a motor service from February that year.

Gallery

References

External links