Sediment transport along an artificial shoreline: “The Strand”, Townsville, NE-Queensland, Australia

Abstract

Construction measures to stabilise or spatially extend coastlines have become a routine measure in urbanised coastal zones. This study quantifies beach profile changes and sediment transport along an artificial beach in Townsville, NE-Queensland. The “Strand” was transformed from a single degraded shoreline into a shoreline with five embayments (or “pocket beaches”) split by four artificial rocky headlands in 1998. The modified shoreline has had an impact on the local and regional northward long-shore sediment pathway, creating local shifts in sand. Sediment deposition and erosion occur at the same time at different parts of the pocket beaches. Collected offshore sediments show that little artificial sand is transported more than a few meters seaward in the south-eastern part of the Strand, while substantial and long-ranging export, i.e., tens to hundreds of meters, occurs in the north-western area. This is mainly the result of the breakwaters south of the Strand, which impacts the predominant northward long-shore sediment transport induced by the dominant south-easterly winds.