An Economical Approach Towards Bathymetric Mapping of Shallow Water Basins Using Unmanned Surface Vessel
Authors: Shetty Devdas , Kotian Rakshith , Sequeira Steevan Loyd , N. R. Pavithra , Pruthviraj Umesh , Gangadharan K. V. 
Published: February 2023

Abstract
In recent years, the use of unmanned vehicles has advanced because of a growing number of civil applications such as firefighting or non-military security work, such as surveillance of pipelines etc. The application of these technologies with decreased cost and size has received attention in both civil and military applications. Recent advances in sensors, modeling and simulation and availability of open-source software and hardware for data integration has created an environment of remotely monitoring that was not possible a few years ago. This paper examines a niche cost-effective, portable Unmanned Surface Vessel that has been designed to capture the bathymetric profile of shallow water basins using single beam echosounder. Bathymetry is the measurement of the depth of water in oceans, rivers, or lakes. Bathymetric maps look a lot like topographic maps, which use lines to show the shape and elevation of land features. Today, echo sounders are used to make bathymetric measurements. Global shallow water bathymetry maps offer critical information to inform activities such as scientific research, environment protection, and marine transportation. Accurate mapping of shallow bathymetry is critical for understanding and characterizing coastal environments providing a foundation for measuring underwater light density, mapping and monitoring and planning marine operations and transportation. Methods for estimating shallow water bathymetry have suffered from a variety of trade-offs and limitations. Conventional methods such as shipborne sounding or airborne LiDAR have limited spatial coverage. The unit described in this paper has been designed and has been trained to acquire data in a predefined set path, minimizing the human intervention and the associated errors. A successful trial run was done for mapping the bed profile of the river basin in India. The vessel has been upskilled for capturing sonar data sets, with water quality parameters and soil samples using an automated auger. The vessel functions using the combined various open-source software and hardware tools for data assimilation, while the captured data sets are real-time transferred using IOT to Ground Controlled Station. The tropical river basin chosen is a part of Netravati River located in Dakshina Kannada District, Karnataka, India. This area is a part of the monsoon belt, and the Netravati riverbed is subjected to heavy sand deposition during a part of the year. The data on the excessive sand deposition is of immense value to the district and state administration. This study has been carried out at a frequency of 30 days and is provided as an input during non-monsoon period for district administration for outlining removal of excessive sand deposition monitoring of water quality in the estuarine ecosystem. The work done is a one-of-a-kind pilot study developed in-house using the recent advances seen in the world of open-source platforms. This paper demonstrates a unique application that is of value to the state administration in decision making and in addition contributes to environmental monitoring of the riverbed.