A GIS approach to sediment displacement in mixed sand and gravel beach environments.

Mixed sand and gravel beaches pose special management issues as they are morphologically distinct from either pure sand or shingle beaches. On the mixed sand and gravel beaches of the Canterbury Bight, New Zealand, displacement of sediments operates within a two-part sediment transport system. The large sediments are retained in the beaches, while the fine sand, silt, and mud are transported offshore to the continental shelf.

A GIS approach to model sediment reduction susceptibility of mixed sand and gravel beaches.

The morphological form of mixed sand and gravel beaches is distinct, and the process/response system and complex dynamics of these beaches are not well understood. Process response models developed for pure sand or gravel beaches cannot be directly applied to these beaches. The Canterbury Bight coastline is apparently abundantly supplied with sediments from large rivers and coastal alluvial cliffs, but a large part of this coastline is experiencing long-term erosion.