The Piako River is a lowland river system that drains into the Firth of Thames on the North Island of New Zealand. Together with the Waihou River, it is one of the two main rivers systems which drains the Hauraki Plains. It is the dominant river system in the Matamata-Piako District, and on its journey it passes through the towns of Morrinsville and Ngatea.
The Piako River has an annual mean flow of 17 m3 sā1 (at Paeroa-Tahuna Road), with a total catchment area of approximately 1,440 km2. The river system is approximately 100 km in length, aligned in a north-south direction and occupies much of the central and western Hauraki Plains (or more broadly, the Thames Valley), extending from Hinuera in the south before discharging into the Firth of Thames in the north, five kilometres west of Thames.
The Piako River has two major stems: the main stem arises in the northern slopes of the Te Miro-Tahuroa hills, descending as two distinct tributaries ā the Piakonui and the Piakoiti Streams. These streams, together with the Toenepi Stream, converge just south of Kereone. On the boundary of Morrinsville, the Waitakaruru Stream, which drains the northwestern Te Miro-Tahuroa Hills, converges with the Piako River. As it progresses north, the Piako River is feed by small streams draining the eastern slopes of the Maungakawa Hills.
The second main stem is that of the Waitoa River, which starts near Piarere. The Waitoa River catchment drains the Hinuera Flats and broad southern Hauraki Plains, before converging with the Piako River in the large wetland known as the Kopuatai Peat Dome, northeast of Tahuna. The Upper Piako River catchment also drains the eastern aspects of the Hapuakohe Range through small tributaries.
The river system is highly modified by intensive dairy farming and associated industry. Given this, the Toenepi Stream - a small sub-catchment of the Piako River - has been extensively used to research the impact of intensive farming on water quality.
Since the 1930s, considerable flood protection measures have been undertaken on the Piako River and surrounding catchment, especially mainly north of Paeroa-Tahuna Road and the Kopuatai Peat Dome. The scheme includes river management works, river diversions and channel enlargement, ponding systems, floodway improvements, stopbanks, floodgates and pumps.
The scheme works includes the following:
- Main river and tributary channel enlargement and clearing work,
- 170 km of stopbanks,
- 59 floodgates and
- 32 pump stations
The scheme provides the following levels of service:
- 100 yr protection from tidal flooding with 0.5m freeboard,
- 50 year protection from Piako River flooding with 0.3m freeboard
Read more about Piako River: Piako River Bridge (Ngatea)
Famous quotes containing the word river:
“It is from quiet places like this all over the world that the forces accumulate which presently will overbear any attempt to accomplish evil on a large scale. Like the rivulets gathering into the river, and the river into the seas, there come from communities like this streams that fertilize the consciences of men, and it is the conscience of the world that we are trying to place upon the throne which others would usurp.”
—Woodrow Wilson (1856–1924)