Water Depth Mapping with Unmanned Surface Vehicle and Developing Equation for Continuously Tracking Water Volume using Satellite

Abstract

The objective of this research is to apply Sentinel-2 satellite imagery to estimate and develop a water depth calculation model. The research integrates the Satellite-Derived Bathymetry (SDB) technique with the Log-Band Ratio Method, which compares water reflectance at different wavelengths to generate accurate water depth maps. The results were validated using in-situ depth measurements obtained from an autonomous survey vessel equipped with a single-beam echo sounder. By analyzing the relationship between the logarithmic band ratio and water depth using a first-degree polynomial regression model, the study found that the log-band ratio of Band 2 (Blue) and Band 8 (Near Infrared, NIR) provided the best trend, characterized by a low slope and a positive correlation. When further processed using a highly flexible Random Forest model, the coefficient of determination (R²) reached 0.83, indicating a strong agreement between the satellite-derived depth estimations and field survey data. These findings suggest that Sentinel-2 satellite imagery, combined with the SDB approach, offers a reliable alternative for water depth estimation, reducing the need for direct field surveys. This method can be effectively applied to water resource planning and management, reducing the need for direct field surveys.