New Zealand Journal of Marine and Freshwater Research abstracts

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Hydrodynamics of Manukau Harbour, New Zealand

ROBERT G. BELL
SERGEI V. DUMNOV¹
BRYAN L. WILLIAMS²

National Institute of Water & Atmospheric
Research Ltd
P. O. Box 11 115
Hamilton, New Zealand

MALCOLM J. N. GREIG

National Institute of Water & Atmospheric
Research Ltd
P. O. Box 14 901, Kilbirnie
Wellington, New Zealand

¹Present address: Task Technology Ltd, P. O. Box 68 783, Newton, Auckland, New Zealand.

²Present address: Water, Drainage & Refuse Unit, Works & Services Group, Hamilton City Council, Hamilton, New Zealand.

Abstract  A calibrated two-dimensional finite-element model, which handles flooding/drying of intertidal areas, complemented by field data, has produced information on tidal propagation in Manukau Harbour, New Zealand with reasonably good accuracy. Excluding the upper-harbour inlets, c. 50% of both the amplification and phase lag in the dominant M2 tidal constituent occurs through the deep 10-km-long entrance channel to Puponga Point. The calculation of tidal residuals has isolated flood-directed and ebb-directed residual circulation respectively on either side of Puponga Point, which is a typical pattern for alternating flows around headlands. The model has established the dominance of tidal-driven over wind-driven circulation in most of the harbour except in the upper intertidal areas. Wind-driven circulation in the inner Harbour is characterised by downwind flows over intertidal sand banks with pressure-driven return flows (vertically averaged) in the deeper main channels. Tidal dissipation rates are sufficiently high to inhibit the onset of any summer stratification.

Keywords  tides; currents; numerical model; residual circulation; winds; estuary; Manukau Harbour

New Zealand Journal of Marine and Freshwater Research, 1998, Vol. 32: 81-100

0028-8330/98/3201-0081 $7.00/0 (c) The Royal Society of New Zealand 1998

PDF file of entire paper: medium quality (1891K); (scanned from paper original: notes about this process)

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