Expected changes in sea-level oscillation within harbours resulting from changes in the harbour configuration

Many of New Zealand's harbours have been artificially modified, either reclaimed to provide more land, or dredged to allow larger ships to use them. In making these modifications, other changes can result besides those that are planned. One aspect which is of interest is the change in the character of long waves in the harbours, specifically the tide or seiches. Seiches are free oscillations in an enclosed or semi-enclosed body of water. The changes in these long waves brought about by the modifications might or might not be of benefit - for example, by increasing the harbour depth the tidal velocity might be increased, which would increase the scouring and help deepen the harbour.