Compartmentalisation of beachface sediments along the southwestern coast of Australia

Identification of littoral cells is a prerequisite for the determination of sediment budgets on sandy coasts. In this context, the aims of the project were, first, to investigate the applicability of statistical techniques, p articularly auto-correlation and cluster analysis, to the definition of lit toral cell boundaries; second, add detail to sedimentological and environme ntal observations previously reported for the southwestern Australian coast ; and third, provide a basis for future examination of sediment transport i n a nearshore environment that is generally subject to low wave energy. The alongshore component of sediment compartmentalisation has been determined for the sandy beaches of thr:study area and relationships between environme ntal parameters and beachface sediment characteristics have been establishe d. Using data describing textural and compositional attributes, the systema tic alongshore variation in sediments was determined from the cluster analy sis and auto-correlation. Results from the grouping of sediments were then used in conjunction with geomorphic variables to determine boundaries of si x sediment compartments. Littoral cells are better developed on the souther n sector of the coast where shoreline salients and headlands are larger and act as boundaries. These barriers limit, but do nor prevent, inter-compart ment sediment transport. The findings of this study provide a context for f urther investigation of littoral cell dynamics and coastal sediment transpo rt. The statistical techniques applied to data describing the alongshore di stribution of sediments are readily repeatable in other contexts and have g eneral applicability and offer a rigorous procedure for definition of coast al regions. (C) 1999 Elsevier Science B.V. All rights reserved.