Beach erosion is a natural process by which the coastline is gradually worn away over time, typically as a result of the action of waves, tides, and storms. It can have significant impacts on coastal communities, including damage to infrastructure, such as roads, buildings, and homes, as well as threats to public safety. Beach erosion can also have negative impacts on the environment, including loss of habitat for plants and animals.
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The importance of addressing beach erosion cannot be overstated. Coastal communities rely on beaches for tourism, recreation, and economic development, and the loss of these resources can have serious consequences. In addition, beach erosion can also pose a threat to public safety, as it can lead to the loss of protective barriers such as dunes and seawalls, leaving homes and other structures at risk to damage from storms and flooding.
Climate change is also having a significant impact on beach erosion. Rising sea levels and more frequent and severe storms are exacerbating the erosion process, making it more important than ever to address the issue.
"Half of the world’s beaches could disappear by the end of this century as a result of climate change-induced coastal erosion and rising seas."
Coastal communities around the world are therefore increasingly turning to a variety of tools and technologies, such as drones, to help monitor and address beach erosion.
The Role of Drones for Solving Beach Erosion
Drones, also known as unmanned aerial vehicles (UAVs), have become an increasingly useful tool for surveying and monitoring beach erosion. With their ability to cover large areas very quickly and provide high-resolution images and video, drones can help coastal managers better understand the extent and impact of beach erosion. By conducting regular surveys with drones, municipalities and local communities can track changes in beach erosion over time, helping to identify long-term trends and patterns.
In addition, drones can now be equipped with a variety of sensors that can aid erosion research. This includes payloads using the latest LiDAR equipped cameras, which can detect small changes in elevation on beaches and shorelines.
"Drones can be especially useful for monitoring small projects that require high-resolution details. With rising sea levels, being able to map changes in elevation becomes critical and the best sensor for monitoring elevation at the local level is LiDAR."
Drones can also be used with other existing technology already in use by managers such as GPS and GIS. All of this provides detailed information about the beach and surrounding environment helping those charged with protecting the seashore make more informed decisions to combat beach erosion.
Advantages of Using Drones for Beach Erosion Surveys
Cost-Effective and Efficient
When looking at coastal erosion issues, drones are cheaper and more efficient to operate than traditional methods, such as manned aircraft or ground surveys, for several reasons:
- Overall cost to operate and maintain
- Speed of flights for area covered
- Quality of data captured for time spent
Walking across coastal cliffs or beachfront areas is very time consuming. A ground survey team could take an entire day to cover a one mile stretch of beach, and the data captured would yield a 2D survey map.
Drones can cover large areas very quickly, providing detailed images of the beach and surrounding environment. This makes them particularly useful for surveying large areas of coastline, as they can cover a lot of ground in a relatively short period of time. A drone could cover this same one mile stretch in less than an hour, and capture 1,000 images with a ground sample distance (GSD) of 2.5cm/pixel.
When equipped with high quality RGB cameras and other sensors, such as LiDAR, they can provide extremely detailed information about the topography of the coast by creating high-resolution interactive maps.
"Drones using multispectral cameras ‘see’ in different parts of the electromagnetic spectrum (such as near-infrared and red-edge bands) and can provide powerful insights into wide range of metrics including vegetation health, water body identification and sediment types."
This is particularly useful for identifying erosion hotspots, and for developing strategies to address erosion issues.
Ability to Monitor Beach Erosion Over Time
Continuous monitoring of coastal assets is crucial. City officials aim to keep track of their valuable real estate, developers need to evaluate the effects of their building projects on coastal regions to minimize any harmful impacts, and civil engineers use the gathered data for design and modeling purposes.
Whatever the application might be, you need accurate data that lines up over time. Drone surveying can give you the required level of accuracy needed for a wide range of coastal erosion projects.
"In England alone, 30% of the shoreline is disappearing - and scientists fear this could accelerate as climate change triggers a rise in sea levels and makes extreme weather more common."
By conducting regularly scheduled drone surveys, coastal managers can track changes in beach erosion over time, helping to identify long-term trends and patterns. This can be particularly useful for identifying areas that are at higher risk of erosion and for developing strategies to address erosion issues.
The data collected can provide valuable information such as where a cut-and-fill operation (a procedure in which the elevation of a landform surface is modified by the removal or addition of surface material) needs to take place. Cut-Fill tools in processing software, evaluated from data collected by drones, can summarize the areas and volumes of change where sand might need to be added or taken away.
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Combined Methods with Other Technologies
One of the challenges to adopting drone technologies for many organizations is the existing systems already in place. Many organizations have made large capital investments to collect data using other methods and there is concern that historical data will no longer be usable when adopting newer drone technologies.
Unlike other manual systems, drone data can be used in conjunction with ground surveys, satellite imaging, and GPS/GIS (Geographic Information Systems) to create detailed maps and models of coastal areas. This can allow collaboration between older data collection practices and newer drone technologies.
When using LiDAR sensors, points and flight trajectory data is calibrated and processed to form a dense point cloud and referenced using Ground Control Points (GCPs) to a real-world coordinate system.
"Georeferenced point clouds can be used to generate Digital Elevation Models (DEMS) and orthorectified images which can be exported into Geographical Information Systems (GIS) packages and rendered into textured 3D models for visualisation maps."
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By integrating this type of drone data with GIS and other historical data already collected, coastal managers can create even higher resolution maps of the beach and surrounding area, while not having to abandon the investment already made in previous data collection systems.
Using Drones in Coastal Management: Case Studies
Coastal areas are often among the most valuable land areas and their maintenance is vital for local communities. In this section, we will examine a few case studies where drones have been effectively used to survey and monitor beach erosion. Some examples of where this is already taking place include:
- UK Drones Supporting Coastal Erosion Monitoring & Protection
- East Coast Australia
- Using drones to monitor coastal erosion in Ghana
- Drone as a tool for coastal flood monitoring in the Volta Delta, Ghana
- Wales: West Coast Monitoring Center
Taking a closer look at two additional case studies below will show the extent to which drones have helped with monitoring and restoration of coastal beach erosion issues.
Avalon Beach New Jersey
Avalon Beach is part of a 7 mile stretch of white sand beaches attached to Stone Harbor Island on the southern Atlantic coast of New Jersey. Due to severe erosion, 11.7 acres of public shoreline in Avalon Beach required sediment replenishment to protect against future hurricane and coastal storm damage. A total of 64,000 cubic yards of sand were transported and spread along the affected area. The use of drones during the renourishment process was essential for creating documentation, communicating with the public, and evaluating the project’s adherence to construction plans.
Restoration projects have many challenges that drone technology can alleviate, especially with historical record data as the beach changes over time. Avalon Beach has gone through several different fill projects using different methods that have had different results. The Avalon/Stone Harbor Beach Fill Project in 2017 first used drone progress photos and videos data that can now be combined with new drone data from the 2022–2023 project.
One of the difficulties that contractors encountered during the 2022 restoration project was dealing with weather-related issues during the cut-fill operation. Challenges like these can be greatly assisted by drone data collected before and after storms, allowing for immediate adjustments to be made.
"Our contractor made progress on the project before a seven-day nor’easter erased the work, and took even more sand from north end beaches."
Along with topographic and other map data, drones were essential in providing up to date progress data for managers to review before and after weather events to determine if and when weather had reversed the work already done.
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The Case of Almenara-Sagunto
Another case study of the Spanish Mediterranean Coast looked at how drones are being used in management of coastal areas. The area studied was the Valencian Oval, located on the Spanish Mediterranean coast, and an area that registers significant coastal erosion. The stability of this coastal region is becoming increasingly important due to risks from rising sea levels. Management strategies have stated that “sedimentary materials play an increasingly important role in determining the amount of damage from flooding and erosion” and capturing this data for quick analysis has become more important.
Research in the past had taken tracking techniques from Landsat satellite imagery, Sentinel 2, GIS, and terrestrial surveys to obtain the morphology and scale of sandbar data to determine sediment shifts, but it never fully solved resolution issues and small-scale dimensional changes.
"Research has been developed to create coastal monitoring with Unmanned Aerial Vehicles (UAVs) that allow data to be obtained and methodologies that integrate computer vision algorithms for 3D and image processing techniques for analysis, combined with maritime information."
Using this research for precision monitoring of the geometry of the coast, the project engineers first established control areas and ground control points (GCPs) across stretches of the coastline and created profiles for each section. The field work was conducted by UAVs using monthly large-scale geometric surveys processing various types of images and data.
"Photogrammetric flights using the global navigation satellite system (GNSS) base belonging to the air system was used to provide precise georeferencing in real time kinematic (RTK) to the images captured from the air. Flight planning was carried out in grid mode and adapted to the existing terrain in order to obtain homogeneous pixel size and precision."
Research was then carried out based on aerial drone photos, which determined the volume of additions and losses of sediments on the coastline. The results captured and analyzed mapped sand compositions in a range from 0.11mm to 2mm with a corresponding height or depth associated with each sediment pattern. This is vital information for beach officials because larger sediment sizes make the beach less inviting during the tourist period, especially for elderly people.
Gathering this drone data allowed managers to see extended periods of time where fine sands had disappeared due to erosion, where sediment in surf zones had shifted to almost gravel size, and where overall general sediment shifts were occurring. Due to their ability to cover large areas of the coast quickly, drones provided officials with nearly real-time information, allowing them to make informed decisions about necessary actions.
Overall, these case studies demonstrate the effectiveness of drones in surveying beach erosion and providing detailed information about the beach and surrounding environment.
The Future of Using Drones for Beach Erosion
Potential for using drones to survey beach erosion in the future
The use of drones for surveying beach erosion is likely to continue to grow in the future. As the technology becomes more advanced and cost-effective, it is likely that more and more coastal communities will turn to drones as a tool for monitoring and addressing erosion issues. Drones are expected to play a key role in helping coastal managers to track changes in erosion over time, identify long-term trends and patterns, and develop strategies to address erosion issues.
Potential limitations or challenges that may arise
There are also potential limitations and challenges to the use of drones for beach erosion surveys. For example, drones are limited in their ability to operate in certain weather conditions, such as strong winds or heavy rain. In addition, there are also privacy and safety concerns that need to be considered when using drones for surveying. For example, there may be concerns about drones flying over private property or crowded areas. These limitations and challenges may need to be carefully considered as the use of drones for beach erosion surveys continues to grow in the future.
How to Start Using Drones for Coastal Monitoring of Beach Erosion
Drones have proven to be a valuable tool for surveying and monitoring beach erosion. With their ability to cover large areas quickly, provide high-resolution images, and access difficult or dangerous areas, drones can help coastal managers better understand the extent and impact of erosion. By using drones in conjunction with other technologies, such as GPS and GIS, coastal managers can create detailed maps and models of the beach and surrounding environment, helping them to identify long-term trends and patterns and make more informed decisions about how to address erosion issues. While there may be limitations and challenges to the use of drones for beach erosion surveys, the potential benefits make them a promising tool for the future of coastal management.
Are you ready to use drones for your next beach rehabilitation project? The Drone Life works with a broad range of organizations who manage large and small beach restoration projects. We have direct experience working with beach erosion issues and will create a tailored aerial solution specific to your needs. We have an expert team of highly qualified licensed professionals ready to document your very own project. You can schedule a free consultation with a drone expert today.
