The stunning coastline of Watchet, Somerset, stands as a testament to the natural beauty and geological significance of the UK’s coastal landscapes. However, this beauty is paired with the harsh reality of coastal erosion, a challenge increasingly worsened by climate change. Recent studies led by geological and ecological consultancy Geckoella have highlighted accelerated erosion and cliff movement at West Street Beach and Cleeve Hill, emphasising the urgent need for advanced monitoring solutions. At the heart of this effort lies drone technology, which has transformed how we approach coastal erosion monitoring.
The Challenge of Coastal Erosion
Coastal erosion is a complex issue influenced by both natural and human factors. Watchet’s coastline, with its second-largest tidal range globally, is particularly vulnerable to tidal forces and the hydrological systems within its cliffs. This dynamic environment results in regular cliff subsidence, rockfalls, and landslides, posing risks to both nature and nearby infrastructure.
Climate change adds another layer of complexity, with rising sea levels and more frequent heavy rainfall accelerating erosion processes. Traditional survey methods, involving manual data collection near cliff edges, are not only labour-intensive and time-consuming but also hazardous, especially in areas prone to sudden collapses.
The Role of Drones in Coastal Erosion Monitoring
Drones have emerged as a revolutionary tool in the fight against coastal erosion. These unmanned aerial vehicles (UAVs) provide a safer, faster, and more reliable means of collecting precise and detailed data, offering critical insights into erosion rates and associated risks.
Improved Safety
One of the key advantages of drone technology is the enhanced safety it provides. Conventional surveying required professionals to work close to cliff edges, exposing them to significant dangers. Drones remove the need for this risky proximity, autonomously capturing data from areas that would otherwise pose a serious threat to human safety.
Enhanced Efficiency
Drones drastically improve the efficiency of data collection. For example, while traditional methods might take an entire day to survey a 1500-metre stretch of cliffs, a drone can achieve the same result in under half an hour. A project by NPS Property Consultants demonstrated this efficiency, with a drone completing two 12-minute flights over a 1500-metre stretch, capturing 763 high-resolution images with a ground sample distance of 2.5 cm per pixel.
Superior Data Quality
The data gathered by drones is not only obtained more quickly but is also of higher quality. Advanced drone cameras, such as the DJI M210’s X4S, allow for close and detailed data collection along cliff edges. This data can be exported into various formats, including Point Clouds, Orthophotos, Digital Elevation Models (DEMs), and Digital Surface Models (DSMs). These outputs support the creation of accurate 2D and 3D maps and models, providing valuable insights for decision-makers.
Repeatability for Long-Term Monitoring
Monitoring coastal erosion is an ongoing endeavour requiring regular data updates. Drones excel in this area, as their flight paths can be precisely repeated using Ground Control Points (GCPs). This ensures consistency in data collection, enabling accurate tracking of changes over time. For instance, NPS Property Consultants conduct drone surveys every six months, allowing them to monitor shifts in cliff alignment and erosion rates consistently.
Case Study: Watchet’s West Street Cliffs
Recent surveys conducted by Geckoella at West Street Beach and Cleeve Hill demonstrate the effectiveness of drone technology. These surveys, commissioned by Somerset Council, aimed to assess cliff stability and geological risks in the area.
Geckoella’s use of drones identified five key zones requiring further monitoring due to active cliff movement. By combining drone data with ground sensors and other indicators, such as the misalignment of roadside kerbstones, they confirmed that erosion and movement rates had increased in several areas. The primary drivers were direct wave action at the cliff base and hydrological effects from increased rainfall and drainage.
Integrating Drone Data with Traditional Methods
While drones are a powerful tool, their effectiveness is maximised when integrated with other monitoring techniques. At Watchet, drone surveys were complemented by geological mapping and ecological appraisals. Ground sensors and physical indicators, like kerbstone misalignment, provided additional data points, creating a holistic view of the site’s conditions and changes over time.
This multi-disciplinary approach ensures comprehensive monitoring, capturing the full scope of changes in the coastal environment.
Implications for the Future
The accelerated erosion observed at Watchet and other UK coastal sites is a stark reminder of the impacts of climate change. As sea levels rise and weather patterns grow more extreme, the need for advanced monitoring strategies will continue to grow.
Drones will be central to these efforts. Their ability to collect high-resolution data safely and efficiently makes them an invaluable asset for understanding and addressing the effects of climate change on our coastlines. By integrating drone technology with other monitoring techniques, we can make more accurate predictions and informed decisions about coastal protection and remediation measures.
Conclusion
Drone technology represents a significant leap forward in coastal erosion monitoring. As demonstrated by the surveys at Watchet’s West Street Beach and Cleeve Hill, drones offer unparalleled safety, efficiency, and data quality. For professionals in the field, the message is clear: embracing drone technology is essential in the fight against coastal erosion.
As we face the challenges of a changing climate, drones will play a critical role in safeguarding our coastlines. By leveraging their capabilities and integrating them with traditional methods, we can better protect both the environment and our communities.
