Tidal asymmetry on the New Zealand coast and its implications for the net transport of sediment

Abstract

Available tidal observations indicate a significant asymmetry in the tide around northernmost New Zealand and in Cook and Foveaux Straits. However only around northernmost New Zealand does the tidal asymmetry dominate the time-averaged mean flow and determine the direction of peak flow; there the tidal asymmetry may have a strong influence on the present development of Pandora Bank.

The relatively large M₄/M₂ tidal elevations in Cook Strait lead to significant tidal asymmetry in the Marlborough Sounds, with the ebb speeds exceeding the flood, and they play an important role in determining the direction of net bedload sediment transport.

Keywords:

• tidal asymmetry
• sediment movement
• North Cape
• Foveaux Strait
• Cook Strait
• Marlborough Sounds