Oriental Bay Beach Development
The sand as reclamation and its retention
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Preparations for the new beach
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Building the submerged reef
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New sand is placed on the beach
The existing sand is not a natural product of the Wellington harbour. The sea wall around Oriental Bay stops any normal degradation of the coastline by wind and water and the coastline is not shaped in a way to capture sand. This area of the harbour is extremely vulnerable to the batterings of northerly storms which tend to move the sand away from the Bay.
In terms of the project, the natural curvature of the bay is being retained and a more extensive beach is being created, augmenting various headlands around the bay in order to retain the new sand. If sand was just “dumped" into the area without constructing, very subtly, a series of structures to keep it in place, it would disappear over a couple of weeks.
A barge measuring 100 metres in length and 25 metres in width was used to bring sand, from a hillside near Takaka, to its new home at Oriental Bay. By the end of May 2003, nearly two thirds of the new sand was deposited on the main Oriental Bay beach and the new beach east of the Band Rotunda, where it is being filtered and shaped by the waves and tide.
The new sand appears to be “washing away" off the beaches, but this is all part of the process of building the beach. The new sand, because it came from a hillside hasn't been naturally sorted by sea or river water. It has been intentionally placed with a steep edge so the waves will wash over it and filter out finer, almost silt-like materials – leaving on the beach the heavier grains of sand. The sand will also change colour as the finer grains are filtered out, leaving a lighter coloured sand behind.
Silt from sand has also been dumped further out in the bay and sand from the mouth of the Hutt River is being used to fill in a natural depression on the harbour bed near Freyberg Beach – when the sand is dumped into the depression, a plume of silt discolours the water, making it look like sand is being washed out to sea.
One very important aspect in relation to the sand was the relationship with Iwi as a stakeholder. Wellington City Council managed this issue right from the outset before any decisions were made and continued to be in constant contact and communication with local Iwi throughout planning. Both Iwi from the north and south were comfortable with the transporting of sand from Golden Bay to Wellington.
Mission Bay in Auckland as a comparison
Mission Bay in Auckland is an example of a successfully reclaimed beach. The Wellington City Council used the website explanation of this reclamation as a resource along with other relevant information. There were aspects which were similar but also a lot of differences. For example, Oriental Bay doesn't have an extensive grassed area as a back drop but does have the city/sea wall. Mission Bay is inside the very sheltered Waitemata harbour which is most unlike Oriental Bay.
