Monitoring Coastal Erosion with Satellite Imagery: Linking Natural Assets and New Technology

Advanced Geospatial Technology is protecting Coastal Ecosystems, Economies, and Cultural Heritage.

Aerial view of severe coastal erosion affecting a New Zealand beach. The image shows several houses precariously perched at the edge of a steep, eroded cliff. The beach below is partially collapsed, with sand and sediment visibly washed into the turquoise ocean waves. The erosion has dramatically altered the landscape, with sections of the coastline crumbling away, endangering the structures above. — Coastal Property in New Zeland is under pressure from constant storm erosion.

A recent report from the Ministry for the Environment and Stats NZ shows the importance of natural infrastructure in protecting New Zealand's communities, economy, and cultural heritage from coastal erosion. Satellites are already solving this issue of monitoring and evaluation from space.

The Role of Geospatial Analysis in helping with the problem

Satellite image analysis is a critical tool for monitoring coastal erosion. Earth Observation (EO) products from satellites like Sentinel-2 and LANDSAT provide high-resolution, frequent data, enabling effective management strategies. Key benefits include:

Regular Monitoring: Continuous updates to track coastal changes and identify erosion patterns.
Cost-Effective Surveys: Reduces the need for expensive ground surveys, providing a practical solution for large-scale monitoring.
Long-Term Analysis: Historical data allows for understanding long-term trends and differentiating between short-term fluctuations.

Schematic diagram illustrating techniques for investigating the Grand Strand's beach system. Acoustic instruments (sidescan sonar, swath bathymetry, and subbottom profilers) provide data on sediment distribution and seafloor structure. Ground-penetrating radar (GPR) measures sediment thickness on land. Sediment characteristics are determined through direct sampling. The Beach Erosion Research and Monitoring (BERM) program uses elevation measurements to track beach morphology changes. Aerial photography, LIDAR, and Differential GPS (DGPS) ensure accurate data collection and coastal change quantification — Diagram of Multi-Faceted Geospatial Monitoring of Coastal Erosion

The Importance of Natural Coastal Infrastructure

Coastal ecosystems such as dunes and wetlands are foundational natural infrastructure that protect against disasters, support public health, and are crucial for economic stability.

The recent Ministry for the Environment report highlights that the degradation of these systems increases susceptibility to soil erosion, pests, diseases, and climate change impacts. This poses significant economic risks and emphasizes the need for preserving these natural assets.

Animated GIF of coastal erosion monitoring via geospatial analysis — Coastal Erosion Example in North Carolina

How Geospatial Data Enhances Coastal Management

Satellites orbit the Earth in a predictable manner, capturing images of the same location at regular intervals. This continuous data acquisition allows for:

Real-Time Monitoring:

Frequent updates provide a current view of coastal conditions, enabling the identification of erosion patterns and potential risks.

Historical Analysis:

Long-term data archives allow for the analysis of coastal changes over decades, helping to differentiate between short-term fluctuations and long-term trends.

Cost-Effective Satellite Surveys:

Satellite imagery reduces the need for expensive and time-consuming ground surveys, providing a practical solution for large-scale monitoring.

Cultural Impact and Considerations

Coastal erosion not only affects the natural and economic landscape but also has profound cultural implications, particularly for Māori communities. Coastal areas hold significant cultural, spiritual, and historical importance.

Cultural Heritage: Many coastal areas are home to sacred sites, ancestral lands, and important cultural landmarks. Erosion threatens these sites, potentially leading to the loss of invaluable cultural heritage.
Community Engagement: Involving local Māori communities in monitoring and decision-making processes ensures that cultural values and knowledge are respected and integrated into coastal management strategies.
Sustainable Practices: Incorporating mātauranga Māori with modern satellite technology can lead to more sustainable and culturally appropriate coastal management practices.

Collaborative Efforts: Working with Māori leaders and incorporating their knowledge can enhance the accuracy and relevance of satellite data, providing a more comprehensive understanding of coastal changes.
Education and Awareness: Raising awareness about the importance of coastal erosion and the role of satellite technology can help garner support for conservation efforts and sustainable practices.

Key Takeaways from the Ministry Report

Natural Infrastructure: Coastal ecosystems like dunes and wetlands protect against disasters, support public health, and underpin the economy.
Economic Impact: Soil is vital for New Zealand’s economy, with the food and fibre sector contributing $55.3 billion in export revenues.
Erosion Risks: 5% of New Zealand's land is highly erodible, with 182 million tonnes of eroded soil entering waterways in 2022.
Climate Change Effects: Increasing storm intensity and sea level rise due to climate change exacerbate coastal erosion risks.

For more information, visit the NZ Ministry's website: https://environment.govt.nz/news/new-report-highlights-importance-of-natural-assets-and-infrastructure/