The Piako River has an annual mean flow of 17 cubic metres per second (600 cu ft/s) (at Paeroa-Tahuna Road),[1] with a total catchment area of approximately 1,440 square kilometres (560 sq mi).

As the Piako River progresses north, it is fed by numerous small streams draining the eastern slopes of the Hangawera Hills.

[3] 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.

[7] Northern Steamship had a weekly trip from Auckland to Tahuna and back until 1927,[8] calling at Pipiroa, Hopai, Ngatea (Orchard), Kerepehi and Waikaka.

[9] A few years earlier plans had been made to upgrade the main highways in the area, partly with ratepayer funding.