Optimising Survey Approaches for Over-Stabilised Urban Dunes in South Wales

Flatley, A.; Drummond, M.; Cunningham, A.; Alun, E.; Jenkins, R., and Williams, H., 2024. Optimising survey approaches for over-stabilised urban dunes in South Wales. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 438-442. Charlotte (North Carolina), ISSN 0749-0208. Human impacts on urban sand dunes result in significant, albeit poorly understood changes to dune and beach development. Anthropogenic impacts, such as construction and foot traffic contribute to widespread dune damage globally. However, dunes can act as a buffer against storm surges and show significant potential to provide nature-based solutions in the face of climate change impacts. Efforts to quantify both natural dune development and restoration practices now benefit from a multitude of potential survey methods. This paper highlights a series of dune survey approaches across a discontinuous stabilised dune that runs along Swansea Bay, South Wales. Urban Dunes in Swansea have recently undergone trials using sand-trapping fences to encourage seaward expansion to prevent sand from overtopping a seawall and spilling onto local roads. Additionally, this dune system was also damaged during the construction of a new West Pier inner wall in 2021. To quantify both natural dune movement and restoration approaches, surveys were undertaken using lidar derived imagery, uncrewed aerial vehicles (UAV) and a handheld imaging laser scanner. Outputs created high resolution pointclouds to quantify vegetation establishment and geomorphic change. These approaches were compared with traditionally derived transects taken on the dune site to identify best practice. We highlight the capabilities of each approach for urban dune management. The application of a mixed method approach allowed us to examine the benefits and drawbacks of each method to explore how advances in spatial technologies can be best utilised for dune monitoring. We use the Swansea Bay case study to highlight examples of dune restoration approaches and natural dune morphodynamics quantified using spatial methods. With a worldwide trend of dune stabilisation, we contribute to developing best practice survey protocol in urban dunescapes.