[4] In 1989 the Canterbury Regional Council and the Christchurch City Council drilled an exploratory bore near the mouth of the Avon River / Ōtakaro discovering layers of fossils and sediment types that showed the area had experienced shifts between being marine, estuary, swamp and floodplain over the last 2 million years.

[5] The land underneath the Estuary consists of gravel embedded between fine silts and sands deposited by the rivers and sea.

[8] Traditional food gathering or mahinga kai sites of Waitaha, Rapuwai, Kāti Mamoe and subsequently Ngāi Tahu iwi included Ihutai (The Estuary).

[8] The nearest kāika (settlements) included Orua Paeroa at Travis Wetland and Te Kai a Te Karoro pā, which was located near to South New Brighton Park, the latter supporting iwi to reside there throughout each year due to the abundance of food supplied by Ihutai.

[9][10][11] Traditional food sources around Ihutai included pūtangitangi (Paradise Shelduck), pārera (grey duck), tuna (eels), kanakana (lamprey), īnanga (adult whitebait), pātiki (flounder) and pipi (shellfish).