Methodology for Carrying out Measurements of the Tombolo Geomorphic Landform Using Unmanned Aerial and Surface Vehicles near Sopot Pier, Poland

Abstract

The human impact on the ecosystem has been particularly evident in the last century; it transforms the Earth’s surface on an unprecedented scale and brings about irreversible changes. One example is an oceanographic phenomenon known as a tombolo, i.e., a narrow belt connecting the mainland with an island lying near the shore formed as a result of sand and gravel being deposited by sea currents. The phenomenon contributes to an increase in the biogenic substance content in the littoral zone, which leads to increased cyanobacteria blooming in the summer period. Moreover, the debris accumulation in the littoral zone results in the mud formation, which makes the beach landscape less attractive. One of the main features of the tombolo phenomenon is its variability of shape, which includes the form of both the shore and the seabed adjacent to it. Therefore, to describe its size and spatio-temporal variability, it is necessary to apply methods for geodetic (the land) and hydrographic (the sea) measurements that can be carried out in different ways. The aim of the paper is to present the methodology for carrying out measurements of the tombolo oceanographic phenomenon using Unmanned Aerial Vehicles (UAV) and Unmanned Surface Vehicles (USV) on the example of a waterbody adjacent to the Sopot pier. It also presents the results of surveys carried out in November 2019 within this area. The study demonstrated that the integration of two measuring devices whose development began in the second decade of the 20th century, i.e., UAVs and USVs, enables accurate (even up to several centimeters) and reliable determination of the scale and variability of the phenomena occurring in the littoral zone.

Study on the Coastline Evolution in Sopot (2008–2018) Based on Landsat Satellite Imagery

“…Based on conducted analyses, the sandy area increased by 14,170.6 m 2 , which is 24.7% more than in 2008. This is very apparent on the right side of the pier, where a strip of land called tombolo [43][44][45][46] has formed between the shoreline and the yacht marina. The tombolo phenomenon forms as a result of the interaction between the hydrotechnical structure and hydrodynamic processes [58].…”

“…The chosen waterbody is special because a unique oceanographic phenomenon, called tombolo, occurs there as a result of the construction of a nearby marina. This phenomenon leads to a constant shoreline shift towards the sea, which negatively impacts both the aquatic environment and human [43][44][45][46]. Therefore, it seems reasonable to monitor the coastline variability in this waterbody to prevent it from moving, e.g., by performing silting works where appropriate.…”

The Use of Low-Cost Unmanned Aerial Vehicles in the Process of Building Models for Cultural Tourism, 3D Web and Augmented/Mixed Reality Applications

“…Unmanned Aerial Systems (UAS) are widely used in low-cost photogrammetry [ 24 , 25 , 26 , 27 , 28 ]. Even small aerial vehicles (AVs) can provide valuable data for the inventory of inaccessible and dangerous areas or objects.…”

Beach Leveling Using a Remotely Piloted Aircraft System (RPAS): Problems and Solutions

“…Correct coastal modeling needs a three-dimensional reconstruction of the study area [8]. Coastal modeling is represented by digital terrain models (DTMs) of high spatial resolution.…”