New Zealand Journal of Marine and Freshwater Research abstracts

---

Stability of an artificially nourished beach, Balaena Bay, Wellington Harbour, New Zealand

LIONEL CARTER JOHN S. MITCHELL

New Zealand Oceanographic Institute Division of Marine and Freshwater Science Department of Scientific and Industrial Research P. O. Box 12-346, Wellington New Zealand

Abstract Balaena Bay, Wellington Harbour, New Zealand, has a small pocket beach that was covered originally by pebbles and cobbles. In February and October 1982, the beach was nourished with sandy granular gravel, the stability of which was monitored until February 1984. Although isolated from oceanic swell, the new beach readily responded to locally generated wind waves which induced both northwards and southwards longshore drift. The net effect was erosion of the southern beach, aggradation over the central beach, and minor fluctuations at the northern end. Yet despite this mobility nearly all the nourishment sediment was retained in the littoral zone. Beach volumes, calculated for each survey, varied little and sediment distribution patterns revealed negligable transport of nourishment sediment to adjacent beaches and offshore areas. Stability is further confirmed by compositional data which record no preferential loss of the sandstone, argillite, and quartz components. The only compositional changes were the incorporation into the new beach of small (< 10%) quantities of sediment derived from the old beach surface and from biogenic productivity.

Keywords beach stability; nourishment; sediment transport; coastal morphology; beach gravel; sediment composition; wind waves; pocket beach; Balaena Bay; Wellington Harbour Received 20 November 1984; accepted 26 February 1985

New Zealand Journal of Marine and Freshwater Research, 1985, Vol. 19: 535-552Received 20 November 1984; accepted 26 February 1985

PDF file of entire paper: medium quality (2769K); (scanned from paper original: notes about this process)

---

This year's abstracts | Journal home page | All abstracts | Publishing home page