New Brighton Spit / Te Karoro Karoro

The South Brighton Spit progradation, along with the modern shaping of the Avon Heathcote estuary, happened because of accelerated erosion of the Canterbury Plains. This was due to deforestation from Polynesian activity 500-700 years before present. The sediment source of the spit is from the Ashley and Waimakariri rivers to the north and the material has been transported southwards by longshore drift. The spit's further development southwards is limited by both the continual flow of water out of the estuary and the topography of resistant Banks Peninsula volcanic rocks preventing further southward migration of the estuary mouth.

Think about the direction of ocean currents along the east coast and around Banks Peninsula, and their relationship to the formation of the spit, Also think about the part that changing sea levels following the last glacial maximum (from about 18,000 years ago) have had on the position of the coastline, and where the sediment for the spit ultimately originates from. What do you think was the early settlers' motivation to settle on the spit and what prompted its development? Why do you think that the east side of the spit (facing the ocean) is straight whilst the western, estuary facing side is more irregular?