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Transcript of Muriwai
Muriwai Coastal Environment
The sand on Muriwai Beach is titanomagnetite sand, which means that it is rich in iron. Average grain size is less than 0.25mm.
Dominant SW waves result in a net northwards sediment transport of approximately 175,000m3 per year.
Natural vegetation include spinifex, pingao and the ice plant, present on dunes south of Okirimoto stream.
Marram grass was planted by humans to stabilize the dunes in the 1930s.
Aeolian deposition occurs when sand grains meet vegetation and is trapped against it. Behind the vegetation is a zone of zero wind where the sand accumulates, and this causes the dunes to grow steeper and steeper.
Saltation occurs when grains enter the airflow and collide with other grains, causing the impacted grains to be ejected from the air. Saltation hop lengths at Muriwai are about 12-15 times the height of the bounce.
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Muriwai beach is located on the West Coast of Auckland, New Zealand