Application of UAV techniques to expand beach research possibilities: A case study of coarse clastic beach cusps

摘要

Unmanned aerial vehicles (UAVs) have widely been documented as accessible, low cost, high-resolution coastal monitoring platforms. To date, however, UAVs have primarily been employed in coastal research as an alternative to traditional survey methods, such as beach profiling, despite their capabilities far exceeding such uses. In this contribution, we present UAV surveys as a technique to expand upon previous research possibilities through a case study on coarse clastic beach cusps. Currently no consensus exists regarding the primary mechanism responsible for development of these rhythmic features, not least due to the need for more comprehensive and timely observational data. Previous research on beach cusps is limited to repeat monitoring of a small number of cusps, or monitoring large cusp sets at relatively coarse spatial resolution. Here, repeat UAV surveys along a 600 m stretch of composite beach in New Zealand are employed to produce the most comprehensive characterisation of cusp parameters (spacing, amplitude, depth) available to date. Furthermore, the use of UAVs in this mixed sediment environment has made it possible to link cuspate morphology, such as horns and bays, to surface sediment texture. This critical advance provides new opportunities for coupling textural and topographic data in future analyses and modelling approaches. We argue that the enhanced, but still nascent, opportunity to observe morphodynamics using UAV survey methods can be critical to advancing our understanding of complex coastal zone features and changes.