The Estuary of the Heathcote and Avon Rivers / Ihutai is the largest semi-enclosed shallow estuary in Canterbury and remains one of New Zealand's most important coastal wetlands. It is well known as an internationally important habitat for migratory birds, and it is an important recreational playground and educational resource. It was once highly valued for mahinga kai.

The Avon River / Ōtākaro flows through the centre of the city of Christchurch, New Zealand, and out to an estuary, which it shares with the Ōpāwaho / Heathcote River, the Avon Heathcote Estuary / Ihutai.