Monitoring Coastal Vulnerability by Using DEMs Based on UAV Spatial Data

Antonio Minervino Amodio,Carmen Maria Rosskopf,Gianluigi Di Paola

doi:10.3390/ijgi11030155

Abstract

The use of Unmanned Aerial Vehicles (UAVs) represents a rather innovative, quick, and low-cost methodological approach offering applications in several fields of investigation. The present study illustrates the developed method using Digital Elevation Models (DEMs) based on UAV-derived data for evaluating short-term morphological-topographic changes of the beach system and related implications for coastal vulnerability assessment. UAV surveys were performed during the summers of 2019 and 2020 along a beach stretch affected by erosion, located along the central Adriatic coast. Acquired high-resolution aerial photos were used to generate large-scale DEMs as well as orthophotos of the beach using the Structure from Motion (SfM) image processing tool. Comparison of the generated 2019 and 2020 DEMs highlighted significant morphological changes and a sediment volume loss of about 780 m3 within a surface area of about 4400 m2. Based on 20 m spaced beach profiles derived from the DEMs, a coastal vulnerability assessment was performed using the CVA approach that highlighted some significant variations in the CVA index between 2019 and 2020. Results evidence that UAV surveys provide high-resolution topographic data, suitable for specific beach monitoring activities and the updating of some parameters that enter in the CVA model contributing to its correct application.

Highlights

The availability of Digital Surface Models (DSMs) characterized by high spatial resolution and vertical accuracy is becoming more and more important for all studies involving three-dimensional analyses and representations of the environment
This paper deals with the methodological approach based on Unmanned Aerial Vehicles (UAVs)-derived data that we have developed to provide a valid and economically convenient alternative for coastal monitoring and the assessment of coastal vulnerability to erosion and inundation, defined as the hazard or susceptibility of a specified coastal system [32,33]
Results obtained highlight that the use of UAVs can represent a breakthrough in the study and monitoring of morphological changes induced by coastal dynamics

Summary

Introduction

The availability of Digital Surface Models (DSMs) characterized by high spatial resolution and vertical accuracy is becoming more and more important for all studies involving three-dimensional analyses and representations of the environment. Most traditional methods for mapping and monitoring coastal environments, such as visual interpretations of topographic maps and aerial photos, require a lot of time and effort, and may not cover the most recent time intervals Remote sensing techniques, such as Interferometric Synthetic Aperture Radar (InSAR), Airborne Light Detection and Ranging (LiDAR) and other geophysical techniques (gravimetric, electrical and geomagnetic methods), have generated large amounts of high-accuracy and high-density topographical measurements over the last 40 years, allowing for regular updating of coastal environments and automated mapping [1–6]. Some of these techniques generate highresolution Digital Elevation Models (DEMs), providing a high level of detail that allows the delineation and analysis of small-scale geomorphic elements [7,8]. These technologies have significant costs that make them prohibitive for several countries and institutions and difficult to be implemented on a regular basis [9]

Methods

Results

Discussion

Conclusion