Shifting shores: investigating shoreline and dune toe movements at pauanui in the face of climate change
- Author
- Short V
- Year
- 2025
- Journal / Source
- MSc in Environmental Science
- Publisher / Organisation
- University of Auckland
- Pages
- 120
- Summary
- This research investigates the projected shoreline and dune toe retreat on Pauanui Beach, Coromandel, New Zealand, under climate change. Using the data-driven model of SPADS, shoreline movement is projected up to 2100. Dune toe retreat is estimated from these projections for three management scenarios: no management, conservative dune restoration, and moderate restoration. The latter two scenarios account for ongoing vegetation restoration efforts initiated in 2021 by reducing dune retreat rates by 20% and 40%, respectively. This study provides quantitative insights into Pauanui’s coastal changes under various climate change scenarios, particularly sea-level rise, and establishes an initial foundation for evaluating dune restoration as a management strategy. Projections indicate that Pauanui’s shoreline is expected to retreat by 21 m under SSP 4.5 and 28 m under SSP 8.5 by 2100, relative to the current position, with fluctuations of up to 13 m. Dune toe retreat, without intervention, is projected to range from 20–25 m under SSP 4.5 and SSP 8.5, while restoration efforts could reduce this by 4–10 m, depending on management intensity and the climate scenario. These findings demonstrate that restoration slows dune toe retreat and delays property encroachment until the late 21st century, providing about a decade of additional resilience compared to unmanaged dune scenarios. However, current dune restoration efforts at Pauanui are insufficient to prevent the inevitable retreat of the dunes into property boundaries by 2100. Thus, complementary management strategies are recommended. This study challenges the notion that dune restoration is merely a short-term management approach, emphasising its role as an essential interim measure within a comprehensive strategy to address climate change impacts. It underscores the need for more proactive interventions at Pauanui Beach and presents an improved Shoreline Adaptation Management Pathway plan to support future decision-making by the Thames-Coromandel District Council. Integrating current restoration strategies with complementary measures will enhance Pauanui Beach’s capacity to safeguard its coastal environment and mitigate risks to the community against future challenges.