A Comparison of Four Different Beach Profiling Techniques at St Leonards, Victoria – An Example of a Collaborative Stakeholder Research Project

Abstract:

Many beaches in Australia are under attack from shoreline erosion due rising sea levels and the action of waves. St Leonard’s beach, a tourist town on the Victorian coastline, is of concern from this destructive erosion and the threat to the economic stability of the town. The major cause of erosion in this area is related to waves created from strong to gale force north to north-easterly winds. This in turn produces a northerly longshore current along with sediment suspension leading to a negative sediment budget. Ongoing and systematic monitoring of the shoreline movement is important to ensure the coast is understood and effectively managed now and into the future. Coastal land managers and agencies are required to find ‘cost-effective’ and ‘fit-for-purpose’ coastal monitoring methodologies which are affordable and efficient.

This project forges a collaboration of stakeholders from academia, public sector land manager, local government and the private sector to compare four different methods of obtaining beach profiles. The four methods of obtaining beach profiles used for comparison are: 1. traditional survey method along transects using a total station theodolite, 2. traditional survey method along transects using a builder’s grade laser level, 3. a small multi-rotor unmanned aerial vehicle (UAV) to produce a full 3D digital surface model of the study area, and 4. an experimental stationary device to produce a limited 3D model along a designated transect using terrestrial photogrammetric approach via a small GPS enabled camera.

Assessment is made by comparing the method's precision, spatial coverage, expertise and equipment requirements/costs, preparation time, field acquisition time, number of people required in the field, post-acquisition processing time, and applicability for community use. Whilst is must be very clearly stated that all methods proved to be successful, the preliminary results of the “workflow and resourcing” assessment ranked the methods in the following order from highest ranking: 1. Laser levelling, 2. Terrestrial Photogrammetry, 3. Total Station, and 4. UAV aerial survey.

The outcomes of this collaboration will be of great use to coastal management organisations grappling with the effectiveness of the different types of methods which are available for measuring beach profiles.