Jetski-based bathymetric surveying in Rincón, Puerto Rico

Abstract

Puerto Rico is an island with a highly energetic wave climate and extreme surf zone hydrodynamics, which dominate sediment transport and coastal erosion. These effects can be monitored by conducting detailed bathymetric surveys to analyze extreme events. A jetski-based bathymetric surveying system was developed to navigate in the surf zone and be able to navigate in very shallow water. The system includes and single beam echo sounder, a side scan unit, and a highly sensitive GPS receiver, all of which are powered by a solar panel mounted in the jetski. Bathymetric surveys were performed in the municipality of Rincón in the island of Puerto Rico to observe morphological changes in the surf zone. This municipality has suffered from severe erosion during the last several decades. Using the bathymetric surveying system, semi-weekly cross-shore surveys were executed, demonstrating the system's capabilities for acquiring bathymetric data. This data was then compared to existing LIDAR bathymetric data for quality control purposes. After the initial surveying period, Puerto Rico was affected by Tropical Storm Isaac, which caused severe erosion in the coast of Rincón. Employing the platform, surveys were executed before and after the storm. Significant morphology changes were observed as a response of wave forcing, and cross-shore transects were analyzed to understand the damage caused and where the eroded sediment was deposited in the nearshore region.