Coastal Restoration Trust of New Zealand

Coastal Dune Ecosystem Reference Database

Broad classification of New Zealand inlets with emphasis on residence times

Author
Heath, R.A.
Year
1976
Journal / Source
New Zealand Journal of Marine and Freshwater Research
Volume
10
Pages
429-444
Summary
Thirty-two New Zealand coastal inlets are tentatively classified into seven groups with probable similar circulation patterns, based on ratios of their physical parameters: volume, tidal compartment, entrance width, surface area, length, and average width. Eighteen of these have a predominant tidal flow, shown from their small ratio (ß < 4) of tidal compartment to total volume, and the cross-sectional areas of their entrances are controlled by the tidal flow: Moutere, Waimea, Aotea, Whanganui, Avon-Heathcote, Tauranga, Parengarenga, Porirua-Pauatahanui, Kawhia, Nelson, Rangaunu, Raglan, Whangarei, Bluff, Otago, Hokianga, Manu-kau, and Whangaruru. The other fourteen range from long narrow sounds with probable strong vertical circulation (e.g., Pelorus Sound) to large bays with strong mean horizontal circulations (e.g., Tasman and Hawke Bays).Examples of residence time calculated in inlets with ß > 4 are given for Tasman Bay, a bay with a mean horizontal circulation, which has a residence time of 1-3 months, and Pelorus Sound, an inlet with a vertically complex circulation, which has a residence time of about 20 d.