The Avon-Heathcote Estuary Ihutai is an important ecological, cultural, and historical feature of the Christchurch City landscape. Shag Rock/Rapanui stands tall at the mouth, a well known Christchurch landmark. The Estuary is situated on the East Coast of the city, located twelve kilometres from the city centre. It covers an area of 880 hectares with each tide seeing around 11 million cubic metres of water flowing in and out (Christchurch City Council, 2006). The Te Huingi Manu Wildlife Refuge which includes 240 hectares of the Bromley Oxidation Ponds and about 100 hectares of surrounding pastoral land sits along side the Estuary, and in recent years the shores surrounding the Estuary have experienced an increasing amount of urbanisation. The Avon-Heathcote Estuary Ihutai is Canterbury’s largest semi enclosed shallow Estuary (Environment Canterbury, 2007) and has a long history of providing food for the residents of Canterbury.