Whangamarino River
Encyclopedia
The Whangamarino River is a lowland river of the Waikato Region of New Zealand
's North Island
, draining the Whangamarino Wetland and associated farmland catchment. The river converges with the Waikato River
just north of Meremere
. The main tributary is the Maramarua River, which starts in the Hunua Ranges
and forms the northern catchment of the Whangamarino River.
The natural Whangamarino River system, especially the main branch (the southern catchment), has been highly modified due to the lower flood protection scheme of the lower Waikato River
. Prior to these floodworks, the Whangamarino Catchmet was unconnected with Lake Waikere. However due to the Lower Waikato-Waipa Flood Control Scheme, constructed in the 1960's, Lake Waikere was transformed and used for flood retention storage when the nearby Waikato River was in flood. During flood events, the Waikato River now overflows into the transformed Lake Waikere via the Rangiriri Spillway (and the redirected Te Onetea Stream). When the Waikato River conditions are suitable, the flood waters are discharged from Lake Waikere into the Whangamarino River catchment through the artificial Pungarehu Canal.
While the flood scheme has permanently changed the ecology of Lake Waikere, it has also provided broader benefits for the community.
). Due to human activity of draining the wetland for farming and the impact of the flood control scheme, the size of the wetland is about half its natural size. The wetland includes peat bog, swampland, mesotrophic lags, and open water river systems are managed as both Wetland and Wildlife Management reserves by the Department of Conservation
. Importantly, the Wetland is protected by under the Ramsar Convention
(Wetland Protection Treaty).
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
's North Island
North Island
The North Island is one of the two main islands of New Zealand, separated from the much less populous South Island by Cook Strait. The island is in area, making it the world's 14th-largest island...
, draining the Whangamarino Wetland and associated farmland catchment. The river converges with the Waikato River
Waikato River
The Waikato River is the longest river in New Zealand. In the North Island, it runs for 425 kilometres from the eastern slopes of Mount Ruapehu, joining the Tongariro River system and emptying into Lake Taupo, New Zealand's largest lake. It drains Taupo at the lake's northeastern edge, creates the...
just north of Meremere
Meremere
Meremere is a small town in the northern Waikato region in the North Island of New Zealand. It is located on the east bank of the Waikato River, 50 kilometres north of Hamilton....
. The main tributary is the Maramarua River, which starts in the Hunua Ranges
Hunua Ranges
The Hunua Ranges form a block of hilly country to the southeast of Auckland in New Zealand's North Island. They cover some 250 square kilometres , containing 178 km² of parkland, and rise to 688 metres at Kohukohunui...
and forms the northern catchment of the Whangamarino River.
The natural Whangamarino River system, especially the main branch (the southern catchment), has been highly modified due to the lower flood protection scheme of the lower Waikato River
Waikato River
The Waikato River is the longest river in New Zealand. In the North Island, it runs for 425 kilometres from the eastern slopes of Mount Ruapehu, joining the Tongariro River system and emptying into Lake Taupo, New Zealand's largest lake. It drains Taupo at the lake's northeastern edge, creates the...
. Prior to these floodworks, the Whangamarino Catchmet was unconnected with Lake Waikere. However due to the Lower Waikato-Waipa Flood Control Scheme, constructed in the 1960's, Lake Waikere was transformed and used for flood retention storage when the nearby Waikato River was in flood. During flood events, the Waikato River now overflows into the transformed Lake Waikere via the Rangiriri Spillway (and the redirected Te Onetea Stream). When the Waikato River conditions are suitable, the flood waters are discharged from Lake Waikere into the Whangamarino River catchment through the artificial Pungarehu Canal.
While the flood scheme has permanently changed the ecology of Lake Waikere, it has also provided broader benefits for the community.
Whangamarino Wetland
The Whangamarino River includes the large Whangamarino Wetland (5,193 hectares) which is the second largest bog and swamp wetland in the North Island of New Zealand (after the Kopuatai Peat DomeKopuatai Peat Dome
The Kopuatai Peat Dome is a wetland on the Hauraki Plains in New Zealand.The 10,201 ha wetland was listed under the Ramsar Convention in 1989 as a Wetland of International Importance...
). Due to human activity of draining the wetland for farming and the impact of the flood control scheme, the size of the wetland is about half its natural size. The wetland includes peat bog, swampland, mesotrophic lags, and open water river systems are managed as both Wetland and Wildlife Management reserves by the Department of Conservation
Department of Conservation
Department of Conservation may refer to:* Agriculture, Fisheries and Conservation Department, Hong Kong* Department of Environment and Conservation * Department of Conservation * In the United States:...
. Importantly, the Wetland is protected by under the Ramsar Convention
Ramsar Convention
The Ramsar Convention is an international treaty for the conservation and sustainable utilization of wetlands, i.e., to stem the progressive encroachment on and loss of wetlands now and in the future, recognizing the fundamental ecological functions of wetlands and their economic, cultural,...
(Wetland Protection Treaty).