Bathymetric Lidar applications

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Bathymetric Lidar applications

In this article, we examine the evolving landscape of bathymetry with insights from Anders Ekelund, vice president of airborne bathymetric Lidar at Hexagon Geosystems. Beyond mapping seagrass, Ekelund unveils Lidar’s pivotal role in addressing climate-driven challenges, from coastal management to flood prediction. Anticipating a shift towards full waveform data analysis, he emphasizes Hexagon’s expertise in efficiently mapping shallow waters. Experience the precision of airborne Lidar, which is reshaping our comprehension of coastal and underwater environments.

How do you map a seagrass meadow?

An area the size of a football field of seagrass is estimated to disappear every half hour, with huge implications for the planet. The carbon storage potential of seagrass, which can store carbon in its roots several metres deep, is much more powerful than that of forests. Preserving this habitat is therefore essential for climate change mitigation. How do we know that a football field-sized area of seagrass is disappearing every half hour? The truth is that we don’t. Mapping seagrass is complex, and to accurately assess how much of it is disappearing we must map it regularly.  

There is therefore an increasing need for the systematic and accurate mapping of seagrass meadows, which will enable the development of sustainable business models, by tracking the disappearance and regrowth of vegetation that sequesters carbon into the seabed over time. Hexagon’s sustainable investment subsidiary R-evolution has been working with the non-profit organization Beneath The Waves and the government of The Bahamas to create a scalable method for mapping seagrass meadows. Using Leica Geosystems’ bathymetry solutions, they have produced multidimensional, intelligent maps to assess the density of the seagrass ecosystem and its carbon storage potential.

 

Climate change drives the need for bathymetry

Blue carbon (the carbon captured by the world’s ocean and coastal ecosystems) is not the only space where bathymetry contributes to tackling urgent environmental challenges driven by climate change. Approximately 40% of the global population lives near the coast, so that coastal erosion, rising sea levels and natural disasters such as hurricanes, tsunamis and storm surges threaten many communities and populations. In fact, complete small island nations may disappear due to global sea-level rise. Bathymetric surveys are essential for optimizing urban developments, protecting new and existing infrastructure and coastal resource utilization planning.

Inland too, bathymetric solutions are key for river mapping and flood simulations. Climate change forecasts predict a ninefold rise in the frequency and up to a 19% increase in the intensity of rainfall in Western Europe. Bathymetry data from riverbeds, combined with drainage models derived from topographic Lidar, helps develop advanced flood risk analyses and early flood warning systems from weather forecasts that will proactively safeguard communities and critical infrastructure.

Some countries are responding to the need for data-driven flood prediction and mitigation by employing bathymetry. In some regions, airborne topographic/bathymetric data solutions are integrated with boat-based multibeam solutions to form a seamless model from deep water to land. This integration facilitates advanced flood modelling solutions, and more countries are likely to adopt similar approaches in the future.

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