Lake Whangape (also written as Wangape, Whangapu, or Whangapae) is shallow, supertrophic,

lateral Lateral is a geometric term of location which may refer to: Healthcare *Lateral (anatomy), an anatomical direction * Lateral cricoarytenoid muscle * Lateral release (surgery), a surgical procedure on the side of a kneecap Phonetics *Lateral co ...

and the second largest lake (after

Lake Waikare Lake Waikare is the largest of several shallow lakes in the upper floodplain of the Waikato River in New Zealand's North Island. It is a riverine lake, located to the east of Te Kauwhata and 40 kilometres north of Hamilton. It covers . Due to it ...

) in the lower

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 ...

basin in New Zealand. One source said the name translated to 'a large sheet of water', another that it was a chief's name. From the 1860s the catchment has lost most of its

forest cover Forest cover is the amount of forest that covers a particular area of land. It may be measured as relative (in percent) or absolute (in square kilometres/square miles). Around a third of the world's surface is covered with forest, with closed-canop ...

and the lake has changed from clear and rich in aquatic vegetation to a murky, algal lake.

Geology

The lake is a lateral lake, dammed by a levee of the Waikato, probably built up as a result of

sea-level rise Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cryo ...

and sediment from the Taupo Volcanic Zone about 2,000 years ago. To the west of the lake the rocks are made up of the 30m year old (

Tertiary Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...

) Whaingaroa and Glen Massey Formations, the Whaingaroan rocks of the Te Kuiti Group. The Karapiro Formation (part of the Walton subgroup) outcrops towards the east of the lake.

Hot springs

Two springs (ranging from to and many seepages occur along Te Maire Stream, a tributary of the main lake feeder, Awaroa Stream, about west of the lake. They are close to a contact between outcropping Early

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

“

greywacke Greywacke or graywacke (German ''grauwacke'', signifying a grey, earthy rock) is a variety of sandstone generally characterized by its hardness, dark color, and poorly sorted angular grains of quartz, feldspar, and small rock fragments or lit ...

basement” and the overlying Tertiary rocks consisting of

claystones Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. The varying types of mudrocks include siltstone, claystone, mudstone, slate, and shale. Most of the particles of which the stone is composed are less than and are too smal ...

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

s and

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 ...

s. It has been suggested that Waikorea, Naike and Waingaro may all source their water from depths of more than , as they all have similar chemical composition. The springs have been named as Whangape, Awaroa, Naike, Waiora, Te Maire, or Te Puia. In the 1890s boat trips were made to the springs from Rangiriri. In 1868 the temperature was measured at . A 1905 earthquake enlarged the main spring. The springs are on private land and not now open to the public.

History

The lake was on the edge of the area which Ngāti Tipa had settled. At the entrance to the lake, Ngapuhi killed 40 or 50, during the

Musket Wars The Musket Wars were a series of as many as 3,000 battles and raids fought throughout New Zealand (including the Chatham Islands) among Māori between 1807 and 1837, after Māori first obtained muskets and then engaged in an intertribal arms rac ...

in 1832. In 1843, Rev Benjamin Ashwell intervened in a dispute between

Ngāti Pou Waikato Tainui, Waikato or Tainui is a group of Māori ''iwi'' based in Waikato Region, in the western central region of New Zealand's North Island. It is part of the larger Tainui confederation of Polynesian settlers who arrived to New Zealand ...

and

Ngāti Mahuta Ngāti Mahuta is a sub-tribe (or hapū) of the Waikato tribe (or iwi) of Māori in the North Island of New Zealand. The territory (rohe) of Ngāti Mahuta is the Kawhia and Huntly areas of the Waikato region. History Ngāti Mahuta is descended ...

over an eel (

tuna A tuna is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae ( mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max len ...

) weir at the lake outlet. It seems it wasn't fully resolved, for, in 1866, a similar dispute was settled by giving the Ngāti Mahuta hapus,

Ngāti Naho Waikato Tainui, Waikato or Tainui is a group of Māori ''iwi'' based in Waikato Region, in the western central region of New Zealand's North Island. It is part of the larger Tainui confederation of Polynesian settlers who arrived to New Zealand ...

and Ngāti Tipa, equal rights over tuna at the lake. In 1864 the Whangape area was described as inaccessible to the British troops in the

Invasion of the Waikato The Invasion of the Waikato became the largest and most important campaign of the 19th-century New Zealand Wars. Hostilities took place in the North Island of New Zealand between the military forces of the colonial government and a federatio ...

, due to the swamps and bush. Whangape was one of 5 ridings making up Raglan County Council when it was formed in 1876. In the confiscated area, which included the lake, as part of a policy of opening up land for settlement under the deferred payment scheme, the Government built

bridleways A bridle path, also bridleway, equestrian trail, horse riding path, ride, bridle road, or horse trail, is a trail or a thoroughfare that is used by people riding on horses. Trails originally created for use by horses often now serve a wider r ...

from the river, to give access to two blocks. A road to Awaroa was approved in 1878. The northernmost of the 2 routes began at Churchill, a settlement which then stood on the west bank of the river about west of Rangiriri. By 1881, had been opened as far as Glen Murray, through heavy swamp at the Churchill end. By 1883 a through track from the Waikato River to the West Coast was in existence. At the same time another was built from south of the lake, towards the Awaroa. By the middle of 1883, nearly had been opened Work began on roads at Rangiriri in 1889, the first section being to the lake. However, the surrounding roads remained poor, so the lake and its neighbouring streams were used for transport, a Whangape Launch Company being set up in 1906 to convey goods from Rangiriri. Earlier, in 1894, Parliament had been asked to "''have obstructions in the shape of eel weirs removed from the navigable creeks flowing from Whangape Lake into the Waikato River, so as to enable steamers now running on the Waikato River to carry goods for settlers in that district.''" In 1889 the weir had been partly removed to allow a boat to get through.

Water levels

Between 1968 and 2000 the water level in Lake Whangape fluctuated between and above sea level. Water flows into the lake from the Waikato River, when it is high. Since 1999 a weir at the outlet has maintained the minimum water level at .

Pollution

Until at least 1869 the lake was clear enough to see plants growing in the deepest parts and it supported a diverse community of native submerged vegetation. In the 1890s the native forest catchment was cleared for pasture. A 2006 Ministry for the Environment report said water quality was declining. Frequent monitoring by

Waikato Regional Council 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 Peninsula ...

from 2008 to 2013 showed a

Secchi depth The Secchi disk (or Secchi disc), as created in 1865 by Angelo Secchi, is a plain white, circular disk in diameter used to measure water transparency or turbidity in bodies of water. The disc is mounted on a pole or line, and lowered slowly down ...

of 0.04 m to 0.69 m (average 0.24 m) and chlorophyll concentrations exceeding 100 mg m-3. Between 2010 and 2014, 62% of samples exceeded recreational guideline levels for

blue-green algae Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, bl ...

. A health warning was also issued in 2020.

Wildlife

Parts of the lake and wetlands around it were

gazetted A gazette is an official journal, a newspaper of record, or simply a newspaper. In English and French speaking countries, newspaper publishers have applied the name ''Gazette'' since the 17th century; today, numerous weekly and daily newspapers ...

as a Wildlife Management Reserve of in 1986. To the west, Awaroa Wildlife Management Reserve extends up the Awaroa Stream, on of the floodplain.

Aquatic vegetation

Thomas Kirk's 1869 survey found a diverse, low growing mixed plant association. Quillwort (''

Isoetes ''Isoetes'', commonly known as the quillworts, is the only extant genus of plants in the family Isoetaceae, which is in the class of lycopods. There are currently 192 recognized species, with a cosmopolitan distribution but with the individual ...

kirkii''), fennel pondweed, blunt pondweed ('' Potamogeton ochreatus'') and red pondweed ('' Potamogeton cheesemanii'') were abundant, waterwort (''

Elatine ''Elatine'' is one of only two genera in the plant family Elatinaceae, the waterwort family. It contains about 25 species of aquatic plants known generally as waterworts. These are annual or perennial plants found in wet areas worldwide. , Plant ...

gratioloides''), horses mane weed and

horned pondweed ''Zannichellia palustris'', the horned pondweed, is a plant found in fresh to brackish waters in the United States (especially in the Chesapeake Bay), Europe, Asia, Australasia, and South America. It is recognizable by its long, thread like leave ...

were common and ''Lepilaena bilocularis'' and green algae ( charophytes - ''corallina, fibrosa, globularis, Nitella hyalina and Nitella leptostachys'') were also present . The only charophytes remaining by 1993 were ''Nitella'' and ''P. cheesemanii''. It was claimed in 1889 that growth was too lush to allow a canoe to be paddled through parts of the lake. By 1921 the lake was said to be infested with weeds and by 1958 the original vegetation was almost completely replaced by ''

Egeria densa ''Egeria densa'', the large-flowered waterweed or Brazilian waterweed, is a species of '' Egeria'' native to warm temperate South America in southeastern Brazil, Argentina, Chile and Uruguay. It is considered a problematic invasive species due t ...

'', first seen in the Waikato in 1946. ''Elodea Canadensis'' and Indian doab (''

Myriophyllum ''Myriophyllum'' (water milfoil) is a genus of about 69 species of freshwater aquatic plants, with a cosmopolitan distribution. The center of diversity for ''Myriophyllum'' is Australia with 43 recognized species (37 endemic). These submersed ...

triphyllum'')' were also identified. In 1977-1979 the Wildlife Service found the same plants, but also the introduced ''

Potamogeton crispus ''Potamogeton crispus'', the crisp-leaved pondweed, curly pondweed, curly-leaf pondweed or curled pondweed, is a species of aquatic plant (hydrophyte) native to Eurasia but an introduced species and often a noxious weed in North America. Descr ...

'', the native ''

propinquum'' and rediscovered blunt pondweed. In 1987 the macrophyte beds declined to about 10% of the lake area, turbidity increased (possibly due to coal mine waste) and they were dominated by hornwort, another invasive exotic. High levels of suspended sediment and phytoplankton biomass, largely shade out re-establishment of submerged macrophytes.

Fish and other water life

Despite the pollution, 14 fish species live in the lake, with large populations of native fish, including

short-finned eel The short-finned eel (''Anguilla australis''), also known as the shortfin eel, is one of the 15 species of eel in the family Anguillidae. It is native to the lakes, dams and coastal rivers of south-eastern Australia, New Zealand, and much of t ...

(making up the most biomass), ''Galaxias maculatus'', longfin eel,

common bully The common bully (''Gobiomorphus cotidianus''), or toitoi (Māori), is a fish endemic to New Zealand, and is present throughout the country. There are three other bully species that can be confused with common bullies. There are few characterist ...

and

grey mullet Grey mullet can mean any of several fish in the family ''Mugilidae'' (the mullets) and having a greyish hue: * Flathead grey mullet, ''Mugil cephalus'' * Thicklip grey mullet, ''Chelon labrosus'' * Boxlip grey mullet, ''Oedalechilus labeo The bo ...

, as well as pest fish - koi carp (next most biomass, introduced in 1872),

mosquito fish The western Mosquitofish (''Gambusia affinis'') is a North American freshwater fish, also known commonly, if ambiguously, as simply Mosquitofish or by its generic name, ''Gambusia'', or by the common name gambezi. Its sister species, the east ...

catfish Catfish (or catfishes; order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species alive ...

and

goldfish The goldfish (''Carassius auratus'') is a freshwater fish in the family Cyprinidae of order Cypriniformes. It is commonly kept as a pet in indoor aquariums, and is one of the most popular aquarium fish. Goldfish released into the wild have bec ...

. Perhaps due to turbidity created by mining waste, or by koi carp, the native mysid shrimp is the common food of eels, smelt and common bully.

Riparian vegetation

Much of the lakeside vegetation grows in mineralised swamps. 48% of it consists of turf communities, categorised into 21 types, the longest being some of Indian doab–water purslane (

Hydrocotyle ''Hydrocotyle'', also called floating pennywort, water pennywort, Indian pennywort, dollar weed, marsh penny, thick-leaved pennywort and even white rot is a genus of prostrate, perennial aquatic or semi- aquatic plants formerly classified in the ...

hydrophila)

herbfield Herbfields are plant communities dominated by herbaceous plants, especially forbs and grasses. They are found where climatic conditions do not allow large woody plants to grow, such as in subantarctic and alpine tundra environments. Herbfield is ...

'''. The lake supports the largest known population of the indigenous sedge, ''Fimbristylis velata''. Regionally important populations of ''Lobelia perpusilla'' and ''Carex gaudichaudiana'' are present. Dominant species were usually perennials, with the alien Mercer grass and the indigenous emergent spike sedge most common. In 1871 vegetation was dominated by raupo, flax,

sedge The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large, with some 5,500 known species described in about 90 genera, the largest being the "true sedges" genus '' Carex'' ...

kahikatea ''Dacrycarpus dacrydioides'', commonly known as kahikatea (from Māori) and white pine, is a coniferous tree endemic to New Zealand. A podocarp, it is New Zealand's tallest tree, gaining heights of 60 m and a life span of 600 years. It was fi ...

'','' lancewood and shrubs such as '' Raukaua anomalus'' and swamp māhoe ('' Melicytus micranthus''), which remain west of the lake. Raupo remained on much of the lake’s margin until the 1950s, but by 1991 only 9% remained in a narrow fringe. As early as the 1890s willows were mentioned as a problem and in 1917 the river board was clearing the stream of willow. Now the shores have been colonised by crack and

grey willow Grey willow or gray willow may refer to: *'' Salix atrocinerea'', a species of willow native to Europe commonly called grey willow *'' Salix cinerea'', a species of willow native to Europe and western Asia, also occasionally called grey sallow *''S ...

and floating sudds of American primrose willow and Amazonian parrots feather ('' Ludwigia peploides'' and ''

Myriophyllum aquaticum ''Myriophyllum aquaticum'' is a flowering plant, a vascular dicot, commonly called parrot's-feather and parrot feather watermilfoil. Morphology and reproduction Parrot feather is a perennial plant. Parrot feather gets its name from its feather-l ...

'') are now along most of the lake shore. However, a 1991 survey found 541

vascular The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away f ...

species of which 300 were indigenous (and another 13 now apparently extinct there). Endangered or uncommon turf plants include '' Amphibromus fluitans'', '' Fimbristylis velata'', ''

Carex ''Carex'' is a vast genus of more than 2,000 species of grass-like plants in the family Cyperaceae, commonly known as sedges (or seg, in older books). Other members of the family Cyperaceae are also called sedges, however those of genus ''Carex'' ...

cirrhosa'', ''C. gaudichaudiana'', ''

Lachnagrostis ''Lachnagrostis'' is a genus of African, Australian, Pacific Island, and South American plants in the grass family. They are often treated as members of genus ''Agrostis''. ; SpeciesRúgolo de Agrasar, Z. & A. M. Molina. 2002. El género ''Lachn ...

striata'', ''

Pratia ''Pratia'' is a formerly recognized genus of flowering plants in the family Campanulaceae, native to Asia, Australia and New Zealand. Along with other genera, such as ''Hypsela'' and ''Isotoma'', it is now included in ''Lobelia''. Former species i ...

perpusilla'', pillwort and mud buttercup (''

Ranunculus ''Ranunculus'' is a large genus of about almost 1700 to more than 1800 species of flowering plants in the family Ranunculaceae. Members of the genus are known as buttercups, spearworts and water crowfoots. The genus is distributed in Europe ...

limosella''). Threats perceived by DOC were encroachment of the weeds ''

Paspalum distichum ''Paspalum distichum'' is a species of grass. Common names include knotgrass, water finger-grass, couch paspalum, eternity grass, gingergrass, and Thompson grass. Its native range is obscure because it has long been present on most continents, an ...

'', '' Centipeda cunninghamii'', ''

'', and ''

Ludwigia palustris ''Ludwigia palustris'' is a species of flowering plant in the evening primrose family known by the common names marsh seedbox, Hampshire-purslane and water purslane. This is an aquatic or semiaquatic perennial herb which grows in moist to wet ...

'', and the effects of cattle grazing. The Awaroa Reserve is mainly formed of crack willow forest, with some open swamp of flax,

cabbage tree Cabbage tree is a common name for several plant species: * '' Andira inermis'', native to Central and South America * Various members of the genus ''Cordyline'' native to New Zealand. **''Cordyline australis'' (Cabbage tree) **''Cordyline banksii'' ...

, manuka, and

mingimingi Mingimingi is a Māori word meaning 'twisted' or similar. The name is used to describe at least three different species of New Zealand plants: *'' Coprosma propinqua'' (Mingimingi), a widespread small leaved shrub. *'' Leucopogon fasciculatus'' (T ...

. It also has of regularly flooded kahikatea forest, with kowhai,

totara ''Podocarpus totara'' (; from the Maori-language ; the spelling "totara" is also common in English) is a species of podocarp tree endemic to New Zealand. It grows throughout the North Island and northeastern South Island in lowland, montane a ...

, matai, pukatea and climbers, including Supplejack, swamp lawyer, bush lawyer, jasmine and pōuwhiwhi (''

Calystegia ''Calystegia'' (bindweed, false bindweed, or morning glory) is a genus of about 25 species of flowering plants in the bindweed family Convolvulaceae. The genus has a cosmopolitan distribution in temperate and subtropical regions, but with half o ...

tuguriorum'') and haaka ( ''Viola lyalli'') ground cover.

Birds

56 species have been recorded on and around the lake, the commonest being black swan, Canada goose, paradise duck, grey duck (pārera were common in 1905), mallard,

shoveler The shovelers or shovellers are four species of dabbling ducks with long, broad spatula-shaped beaks: * Red shoveler, ''Anas platalea'' * Cape shoveler, ''Anas smithii'' * Australasian shoveler, ''Anas rhynchotis'' * Northern shoveler, ''Anas c ...

and

pukeko The Australasian swamphen (''Porphyrio melanotus'') is a species of swamphen (''Porphyrio'') occurring in eastern Indonesia (the Moluccas, Aru and Kai Islands), Papua New Guinea, Australia and New Zealand. In New Zealand, it is known as the pu ...

. Other birds include

shag Shag, or Shagged, or Shagger, or Shagging, or Shags may refer to: Animals * Shag or cormorant, a bird family ** European shag, a specific species of the shag or cormorant family ** Great cormorant another species of the family People Pseudonym ...

bittern Bitterns are birds belonging to the subfamily Botaurinae of the heron family Ardeidae. Bitterns tend to be shorter-necked and more secretive than other members of the family. They were called ''hæferblæte'' in Old English; the word "bittern ...

, heron, crake,

pied stilt The pied stilt (''Himantopus leucocephalus''), also known as the white-headed stilt, is a shorebird in the family Recurvirostridae. It is widely distributed with a large total population size and apparently stable population trend, occurring in ...

gulls Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari (bird), Lari. They are most closely related to the terns and Skimmer (bird), skimmers and only distantly related to auks, and even more distantly to waders ...

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 Quo ...

and

grebe Grebes () are aquatic diving birds in the order Podicipediformes . Grebes are widely distributed freshwater birds, with some species also found in marine habitats during migration and winter. Some flightless species exist as well, most notably ...

. Since colonisation some birds have been introduced and others have become locally extinct. A pair of mute swans, presented by

Sir George Grey Sir George Grey, KCB (14 April 1812 – 19 September 1898) was a British soldier, explorer, colonial administrator and writer. He served in a succession of governing positions: Governor of South Australia, twice Governor of New Zealand, Go ...

to Captain Hutton, hatched their second brood in 1870, were donated to the Auckland Acclimatisation Society in 1871, by 1873 were a larger flock and, by 1878, there were enough to send some elsewhere. The Society added geese to the lake in 1905. Karakahia, or Australian white-eyed duck once bred on the lake and were reported in 1868.

Restoration

Although the lake is identified as a priority 1 waterbody for stock exclusion in the Waikato Regional Plan, only about a third has been fenced to exclude cattle. A restoration project has fenced of the south shore and planted it with over 20,000 trees. In 2017 Government contributed $900,643, as part of a $2.8m scheme, towards that and accelerated

alligator weed ''Alternanthera philoxeroides'', commonly referred to as alligator weed, is a native species to the temperate regions of South America, which includes Argentina, Brazil, Paraguay and Uruguay. Argentina alone hosts around 27 species that fall with ...

containment, which has been sprayed since 2002. Spraying of alligator weed and yellow flag iris was done again in 2014.

Drainage proposals

Various proposals were made to drain the lake from 1892. Some drainage was done in 1917, when the Rotongaro Canal was cut. In 1956 the local MP,

Hallyburton Johnstone Hallyburton Johnstone (23 August 1897 – 10 August 1970) was a New Zealand politician of the National Party. Biography Johnstone was born in Raglan in 1897, the son of Campbell Johnstone. He was educated at Te Uku, Whata Whata, an ...

, suggested the lake could be turned into farmland "at no great cost", a claim probably based on a 1933 estimate and a 1911 engineers' survey. In 1937 Raglan County Council raised a loan for extensive drainage of the lake.

Boat ramps

There are boat ramps at Whangape Domain and Shuggs Landing. There is also road access to the lake edge at Beverland Rd. To prevent the spread of

, which was first found at the lake in 2003, boats need to be cleaned before and after using the lake. The Domain ramp is hard to access and

Waikato District Council Waikato District Council ( mi, Te Kaunihera ā-Rohe o Waikato) is the territorial authority for the Waikato District of New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of ...

wasn't aware that it owned it.