Figure 79: The flow paths of groundwater at Te Aroha

of Te Aroha the hot springs were recognised as associated with the old volcanic structures and fault lines of Te Aroha mountain:

The Te Aroha group of mineral springs is situated at the base of Te Aroha Mountain the steep wooded face of which, rising abruptly immediately beside the springs is ... a great fault scarp. Through the crushed rock due to this fault-zone arise the springs which occur over an area about 25 chains [580 m] in length, in the northern portion of which the springs are warm, in the southern cold.¹⁸

Figure 79, which is derived from a 1993 study by Woodward Clyde Limited, confirms this interpretation.

Maori tradition ascribes the hot springs to the taniwha, Ureia who left the O-koroire hot springs to gouge out the channel of the Waihou River. He is said to have taken several gourds of hot water from O-koroire to leave at various places, including O-kauia springs and Te Aroha, which lie along the Hauraki fault line.¹⁹

There is little documentation about these springs before 1850, although the Waihou River nearby was the principal travel route in the region. However, few people then lived in this contentious boundary zone between Ngati Haua to the south and Hauraki tribes to the

18.John Henderson and John Bartrum, The Geology of the Aroha Subdivision, Hauraki Auckland, Geological Survey Branch Bulletin 16 (Wellington: Department of Mines, 1913), p30

19.Turoa, p 196