Factors controlling the entrance cross‐sectional areas of four inlets (note)

Abstract

The frequent occurrence of swell in the entrance to Wellington, Lyttelton, and Akaroa Harbours, coupled with the small littoral drift of sediment on adjacent rocky coastlines, appears to promote development of larger entrances than those associated with tidal control in unconsolidated sediment. In contrast to these three harbours, tidally controlled entrances have either bars or banks that protect them from severe swell and act as bypasses to the littoral drift of sediment.The entrance to Paterson Inlet lies on a coast with little sediment transport and further protection from sediment influx is provided by islands located at its entrance.

Coastal oceanography and sedimentology in New Zealand, 1967–91

“…Interestingly, this took place at about the same time as comprehensive work on tidal inlet stability in United States inlets by Jarrett (1976), and drew comment by Mehta (1976) and comparison with United States inlets. In a follow-up paper based on further field data and examples, Heath (1976a) reported that the control on entrance dimensions was also dependent on the nature of the coast which determines the rate of supply of littoral drift to the entrance. The "FurkertHeath" relationship has probably been quoted and applied in every tidal inlet study since, and subsequently Hume & Herdendorf (1988b) warned of its shortcomings and suggested correct usage.…”

“…Thirdly, wide publicity surrounding beach erosion problems at Omaha (e.g., Schofield 1967;Beca Carter Hollings & Ferner Ltd 1976;Noble 1977;Healy 1981a) raised awareness of the interaction of tidal inlets with the adjacent beach and the possible detrimental effects of sand mining at an inlet Inlet stabilisation by groynes and beach nourishment was implemented after much debate, but not everyone agreed with the cause of the erosion nor the means of remedying the problem (Healy 1981a). Building on Furkert's work, Heath (1975) showed that for many inlets about the New Zealand coast the entrance cross-sectional area is linearly related to the tidal compartment (prism). This became known as the "Furkert-Heath" relationship, and was used to characterise inlets as being in states of equilibrium, deposition, or scour.…”

“…Firstly, Heath (1975) brought tidal hydraulics into the picture. Secondly, the first detailed field study of sediment transport and hydrodynamics in a New Zealand tidal inlet was undertaken at Tauranga Harbour (Davies-Colley 1976;DaviesColley & Healy 1978a, 1978b.…”

“…Firstly, Heath (1975) brought tidal hydraulics into the picture. Secondly, the first detailed field study of sediment transport and hydrodynamics in a New Zealand tidal inlet was undertaken at Tauranga Harbour (Davies-Colley 1976;DaviesColley & Healy 1978a, 1978b. Thirdly, wide publicity surrounding beach erosion problems at Omaha (e.g., Schofield 1967;Beca Carter Hollings & Ferner Ltd 1976;Noble 1977;Healy 1981a) raised awareness of the interaction of tidal inlets with the adjacent beach and the possible detrimental effects of sand mining at an inlet Inlet stabilisation by groynes and beach nourishment was implemented after much debate, but not everyone agreed with the cause of the erosion nor the means of remedying the problem (Healy 1981a).…”

“…The first (Heath 1973a) followed the completion of investigations to define the geostrophic circulation around New Zealand. The second was for the period up to 1982 (Heath 1985), by which time considerable progress had been made in our understanding of coastal, fiord, and shelf oceanography. A significant factor in this advance was the introduction of internally recording current meters which allowed long-term current records to be obtained.…”