Close-Range, Remote Sensing of Littoral Zones using a Multi-Platform Topographic / Bathymetric Lidar System

The dynamic conditions of the littoral zone cause frequent changes to bathymetry and significant movement of underwater objects. Littoral zones constitute a wide variety of aquatic environments, including rivers, estuaries, and coastal areas. The shallowness of this domain (< 5 m) creates challenging conditions for technologies to measure and detect change. Many sensor technologies require submergence in water, and these shallow regimes create unique challenges in performance, access, navigation, deployment, viewing, and sensor standoff distance. This environment poses a risk to equipment and personnel due to changing bottom topography, unknown obstructions, and surf conditions. Advancements in Light Detection and Ranging (LiDAR) technologies have made possible the ability to observe this domain from above the water and produce unprecedented 3-D map bathymetry with centimeter-level precision. This breakthrough LiDAR technology in high-resolution mapping, detecting, and identifying objects in shallow waters (< 5m) from above-water platforms (including watercraft, bridges, and drones) offers next generation capability for close-range remote sensing. Rapid and repeatable deployments allow for detailed littoral zone description of coastal restoration efforts, underwater infrastructure assessments, human impacts on coastal environments, and change detection due to storm effects. Data from coral reef beds in Hawaii, jetty restoration in Panama City, FL, and river infrastructure in Japan will be presented to illustrate the capability and its use in scientific investigations of littoral zones.