Protecting Coral Reefs with Aerial Bathymetric LiDAR: A Sustainable Path for Offshore Wind
- Clinton Bravo
- Aug 28
- 6 min read
The Philippines, with its 7,600+ islands, sits at the heart of the Coral Triangle, a global hotspot of marine biodiversity. Coral reefs here are not only rich in life but also central to protecting coastlines, supporting fisheries, and sustaining millions of livelihoods. As the nation looks toward offshore wind development to secure clean energy, a critical challenge emerges: how can we capture accurate seabed data for wind farm projects without disturbing fragile coral ecosystems?
This is where Aerial Bathymetric LiDAR (ABL) steps in. Unlike traditional sonar methods that involve boats and physical contact with the water, ABL uses laser light from the air to map underwater terrain—delivering precision without intrusion. At AB Surveying and Development (ABSD), we are committed to going Above and Beyond by using reef-safe methods that balance sustainability with development.
Why Coral Reefs Matter in the Philippines
For an archipelagic nation exposed to seasonal storms and long coastlines, reefs act like living breakwaters. Their complex, rugose structures dissipate wave energy before it reaches shore, reducing erosion and the force of storm surge. Studies cited in your reference note that reefs can absorb up to 90% of incoming wave energy, a level of protection that directly lowers flood and damage risk for coastal communities (Mulhall, 2009, as cited in Arenas & Botor, 2025). In practical terms, keeping reefs intact helps safeguard homes, ports, roads, and coastal ecosystems.
A related benefit for planning: the same seafloor roughness and slope that make reefs good wave buffers can be measured and mapped using LiDAR-derived terrain metrics (e.g., rugosity, curvature), giving planners evidence-based inputs for coastal defenses and setback rules (Arenas & Botor, 2025). Philippine reefs sit within the broader Coral Triangle, supporting highly diverse benthic communities—including corals, seagrass, macroalgae, and reef-associated species. This habitat mosaic provides nurseries and feeding grounds that sustain nearshore fisheries and help maintain water quality and ecosystem balance. In Talim Bay (Batangas), bathymetric LiDAR enabled the mapping of coral, seagrass, sand, and rock at sub-meter resolution, proving that these habitats can be identified and differentiated from the air without disturbing them (Arenas & Botor, 2025). That same work showed that LiDAR derivatives (slope, roughness/rugosity, curvature) are strong predictors for benthic classification, delivering reliable habitat maps that are directly useful for conservation zoning and monitoring.
Reefs underpin two pillars of coastal livelihoods in the Philippines: fisheries and tourism. Healthy reef systems support small-scale fisheries and draw visitors for snorkeling and diving—activities that circulate income through coastal towns. Damage to reefs therefore doesn’t just harm wildlife; it threatens food security, household income, and local enterprises. Your references emphasize reefs’ combined coastal protection and ecosystem service value, reinforcing why conservation is not merely ecological—it’s economic (Mulhall, 2009, as cited in Arenas & Botor, 2025). Because ABL is non-contact and fast, it helps agencies and developers obtain the site-scale detail they need (habitat boundaries, depth, and terrain) without jeopardizing the assets communities depend on (Arenas & Botor, 2025; Kujawa & Remondino, 2025).
Risks of Traditional Surveying
Traditional boat-based sonar surveys can pose risks in reef-rich waters:
Physical disturbance: Boat operations in shallow reef zones come with contact risks. Anchors, chains, and even careful maneuvering can strike or scrape living coral, and tow cables or sensor gear increase the chance of snagging on coral heads or reef structures. Hull-mounted multibeam reduces some risks but still requires close vessel operations in tight, shallow spaces. In contrast, aerial bathymetric LiDAR collects depth data from the air, so there’s no equipment in the water and no chance of direct contact with corals (Arenas & Botor, 2025; Kujawa & Remondino, 2025).
Sediment plumes: Propeller wash and repeated passes over a site re-suspend bottom sediments. That cloud can smother coral polyps, reduce light, and stress seagrass and filter feeders. Sediment plumes are a particular concern on shallow reef flats where vessels must maneuver slowly and repeatedly to achieve full coverage. Because ABL is flown above the water, it doesn’t generate prop wash or near-bottom turbulence, greatly reducing the chance of sediment-related stress to benthic habitats (Arenas & Botor, 2025).
Noise pollution: Sonar pulses may disrupt fish and marine mammals. In sensitive areas, additional noise may disrupt the behavior of fishes and other marine life. aerial bathymetric LiDAR, by design, does not introduce underwater sound during data capture, making it a lower-disturbance option for Marine Protected Areas and biodiversity hotspots (Kujawa & Remondino, 2025).
CASE 1: Evidence from the Philippines: Why LiDAR Was Preferable in Coral-Dense Sites
In Talim Bay (Batangas), Arenas & Botor (2025) used bathymetric LiDAR derivatives—like slope, curvature, and rugosity—alongside imagery to map coral, seagrass, sand, and rock at sub-meter resolution. Their machine-learning workflow achieved about 93.4% classification accuracy, showing that ABL can deliver decision-ready habitat maps without placing vessels and towed gear in sensitive coral zones. The authors highlight ABL’s non-contact data collection as a key reason it is more suitable than boat-based methods in coral-dense areas (Arenas & Botor, 2025).
Kujawa & Remondino (2025) reach a similar high-level conclusion from a broader review: in shallow-water scenarios, image- and LiDAR-based approaches provide efficient, wide-area mapping and reduce in-water disturbance, with the important caveat that water clarity limits LiDAR penetration. Where conditions are suitable (clear, shallow water), ABL is both effective and less intrusive.
How Aerial Bathymetric LiDAR Protects Coral Reefs
Non-Invasive Mapping: Traditional surveys require vessels—meaning anchors dropped on reef flats, hulls and propellers maneuvering in shallow waters, and even the risk of scratching or breaking coral structures during data collection.
Large-Scale Coverage for an Archipelago: In a country of scattered islands, surveying by boat can take weeks. ABL can cover tens of square kilometers in a single flight, making it ideal for regional offshore wind planning across multiple reef-rich sites.
High-Resolution Habitat Classification: Beyond simple depth data, ABL generates derivatives like slope, roughness, and curvature—all critical for distinguishing habitat types. Arenas & Botor (2025) demonstrated a 93.4% classification accuracy when combining LiDAR data with satellite imagery and AI-based workflows.
Enabling Reef-Safe Offshore Wind: By clearly identifying reef areas and suitable zones for turbine foundations, ABL supports developers in avoiding sensitive habitats while still accessing viable offshore wind resources.
Learnings from Reef-Safe Mapping in the Philippine Context
Efficiency in an Archipelago: ABL reduces time at sea, making surveys safer, faster, and more cost-effective compared to vessel-only operations.
Data Richness: Based on these two images above, LiDAR provides both seabed depth and habitat classification, giving developers a full environmental and engineering picture.
Biodiversity Protection: Protecting coral reefs ensures fisheries and coastal resilience remain intact even as offshore wind projects expand.
Policy Implications: Reef-safe survey technologies like ABL can be integrated into Environmental Impact Assessments (EIA), strengthening the Philippines’ commitment to climate resilience and biodiversity protection.
ABL is not without challenges. Its effectiveness depends on water clarity (typically limited to ~30 m depth or 2.5x Secchi disk depth), and it cannot fully replace sonar in deep offshore waters. For comprehensive datasets, ABL is best combined with:
MBES for deep-water detail.
Sub-bottom profiling for sediment layers.
Magnetometry for detecting buried infrastructure.
At ABSD, we design customized hybrid surveys for offshore wind developers:
Aerial LiDAR for shallow, reef-rich waters.
Multibeam sonar for deeper offshore zones.
Geophysical methods for subsurface and structural data.
AI-assisted classification for faster, smarter habitat mapping.
The Philippines’ coral reefs are priceless protecting them while advancing renewable energy is both a responsibility and an opportunity. Aerial Bathymetric LiDAR offers a way to achieve this balance: delivering accurate seabed data for offshore wind development without disturbing fragile marine ecosystems.
Safeguarding reefs means safeguarding our future, coastal protection, food security, and the credibility of the clean-energy transition. Aerial Bathymetric LiDAR gives us the precision to plan offshore wind responsibly; hybridizing it with the right acoustic and geophysical tools ensures nothing critical is missed. That’s the balance ABSD delivers: decision-ready data, minimal disturbance, maximum confidence.
At ABSD, we go Above and Beyond by integrating ABL into hybrid survey workflows, ensuring every dataset we deliver is not just precise, but also environmentally responsible. Because in an archipelago like the Philippines, safeguarding reefs means safeguarding our future.
Get in touch with us at info@absurveyingph.net or
visit www.absurveyingph.net to connect with #TheLidarGuys and explore tailored geospatial solutions that go above and beyond.
References
Arenas, I. R. A., & Botor, J. B. B. (2025). Development and comparative assessment of methodologies for benthic feature classification using bathymetric LiDAR and machine learning [Undergraduate thesis, University of the Philippines Diliman].
Kujawa, P., & Remondino, F. (2025). A review of image- and LiDAR-based mapping of shallow water scenarios. Remote Sensing, 17(12), 2086. https://doi.org/10.3390/rs17122086
Mulhall, M. (2009). Saving rainforests of the sea: An analysis of international efforts to conserve coral reefs. Journal of International Wildlife Law & Policy, 12(1), 1–46.
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