Beach Morphology and Sediments of the Canterbury Bight
- Author
- Kirk, RM.
- Year
- 1967
- Journal / Source
- unpublished MA
- Publisher / Organisation
- Department of Geography, University of Canterbury
- Pages
- 245 pp
- Summary
- The 84 miles of mixed sand and shingle beach between Banks Peninsula and Dashing Rocks, Timaru, is.a high energy shoreline exposed to vigorous wave action emanating. from the south Pacific Ocean. Much of the coastline is actively retrograding. However, short term and seasonal variations in beach profiles are small. This is unusual in relation to previous studies of shingle beaches. Analysis of wave processes and of beach slopes and materials indicates that beach morphology is in short term erosional equilibrium with the prevailing south-easterly swell and with southerly storm waves. Long term changes in beach profiles indicate that, over much of the Canterbury Bight, the narrow profile envelopes are retreating landward. There is an excess of wave energy over the supply of materials and so the profiles are becoming wider and flatter. This condition is termed sub-equilibrium.