The Pakoka River is a river of the

Waikato Region Waikato () is a local government region of the upper North Island of New Zealand. It covers the Waikato District, Waipa District, Matamata-Piako District, South Waikato District and Hamilton City, as well as Hauraki, Coromandel Peninsul ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

's North Island. It flows southwest from its source southeast of Raglan to reach the northeastern end of the

Aotea Harbour Aotea Harbour ( mi, Aotea Moana) is a settlement and smallest of three large natural inlets in the Tasman Sea coast of the Waikato region of New Zealand's North Island. It is located between Raglan Harbour to the north and Kawhia Harbour to the ...

. The catchment is made up of just over of waterways.

Geology

The most notable features of the Pakoka valley were formed by Upper

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...

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 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 epoch, about 150 million years ago) poorly sorted conglomerate of

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

and siltstone, containing

andesitic Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomin ...

pebbles up to in diameter. A rock arch and several notable bluffs are formed of late Whaingaroan Ahirau

Sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

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 Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines. In zoology ''Calcareous'' is used as an ad ...

, fine sandstone. Apart from recent

alluvial Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. All ...

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

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...

feldspathic Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldsp ...

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 The New Zealand fernbird or simply fernbird (''Poodytes punctatus'') is an insectivorous bird endemic to New Zealand. In the Māori language, it is named or . Taxonomy The New Zealand fernbird was described by the French zoologists Jean Quoy ...

and

Spotless crake The spotless crake (''Zapornia tabuensis'') is a species of bird in the rail family, Rallidae. It is widely distributed species occurring from the Philippines, New Guinea and Australia, across the southern Pacific Ocean to the Marquesas Islands a ...

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 Akeake is the name of at least three New Zealand species of tree: *''Dodonaea viscosa'', akeake *''Olearia avicenniifolia'', mountain akeake or tree daisy *''Olearia traversiorum'', Chatham Island akeake or Chatham Island tree daisy The species a ...

, kanuka and kowhai lines the estuary arm.

Spartina ''Spartina'' is a taxon of plants in the grass family, frequently found in coastal salt marshes. Its species are commonly known as cordgrass or cord-grass, and are native to the coasts of the Atlantic Ocean in western and southern Europe, nort ...

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 Seagrasses are the only flowering plants which grow in marine environments. There are about 60 species of fully marine seagrasses which belong to four families (Posidoniaceae, Zosteraceae, Hydrocharitaceae and Cymodoceaceae), all in the or ...

are found on the mud flats around the corner where the river widens out. The farmland is not fenced along the eft bankand stock access is potentially a problem. A mature (~10 years?) flowering

mangrove A mangrove is a shrub or tree that grows in coastal saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evolution in severa ...

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 Mitigation is the reduction of something harmful or the reduction of its harmful effects. It may refer to measures taken to reduce the harmful effects of hazards that remain ''in potentia'', or to manage harmful incidents that have already occur ...

funding from

Te Uku Wind Farm Te Uku Wind Farm is a wind farm at Te Uku near Raglan, New Zealand. It has a capacity of 64MW using 28 wind turbines. Construction was completed in March 2011, at a cost of $200 million. The farm covers an area of approximately . The 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 Bridal Veil Falls. This has been followed by a possum 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 Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate s ...

are to pollution. The NIWA Freshwater Fish Database shows the Pakoka has longfin eel, koura, Cran's Bully (''Gobiomorphus basalis'') and

redfin bully The redfin bully (''Gobiomorphus huttoni'') is a species of freshwater fish in the family Eleotridae endemic to New Zealand. Being amphidromous, it spends part of its life cycle at sea. Males have distinctive bright red patterns and stripes on t ...

, 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