Long and Short-Term Coastal Changes Assessment Using Earth Observation Data and GIS Analysis: The Case of Sperchios River Delta

The present study provides information about the evolution of the Sperchios River deltaic area over the last 6500 years. Coastal changes, due to natural phenomena and anthropogenic activities, were analyzed utilizing a variety of geospatial data such as historic records, topographic maps, aerial photos, and satellite images, covering a period from 4500 BC to 2020. A qualitative approach for the period, from 4500 BC to 1852, and a quantitative analysis, from 1852 to the present day, were employed. Considering their scale and overall quality, the data were processed and georeferenced in detail based on the very high-resolution orthophoto datasets of the area. Then, the multitemporal shorelines were delineated in a geographical information system platform. Two different methods were utilized for the estimation of the shoreline changes and trends, namely the coastal change area method and the cross-section analysis, by implementing the digital shoreline analysis system with two statistical approaches, the end point rate and the linear regression rate. Significant river flow and coastline changes were observed with the overall increase in the delta area throughout the study period reaching 135 km2 (mean annual growth of 0.02 km2/yr) and the higher accretion rates to be detected during the periods 1805–1852, 1908–1945 and 1960–1986, especially at the central and north part of the gulf. During the last three decades, the coastline has remained relatively stable with a decreasing tendency, which, along with the expected sea-level rise due to climate change, can infer significant threats for the coastal zone in the near future.

Detection and tracking of belugas, kayaks and motorized boats in drone video using deep learning

Aerial imagery surveys are commonly used in marine mammal research to determine population size, distribution and habitat use. Analysis of aerial photos involves hours of manually identifying individuals present in each image and converting raw counts into useable biological statistics. Our research proposes the use of deep learning algorithms to increase the efficiency of the marine mammal research workflow. To test the feasibility of this proposal, the existing YOLOv4 convolutional neural network model was trained to detect belugas, kayaks and motorized boats in oblique drone imagery, collected from a stationary tethered system. Automated computer-based object detection achieved the following precision and recall, respectively, for each class: beluga = 74%/72%; boat = 97%/99%; and kayak = 96%/96%. We then tested the performance of computer vision tracking of belugas and manned watercraft in drone videos using the DeepSORT tracking algorithm, which achieved a multiple-object tracking accuracy (MOTA) ranging from 37% – 88% and multiple object tracking precision (MOTP) between 63% – 86%. Results from this research indicate that deep learning technology can detect and track features more consistently than human annotators, allowing for larger datasets to be processed within a fraction of the time while avoiding discrepancies introduced by labeling fatigue or multiple human annotators.

Quantification of green areas

The monitoring of green areas has been researched and analyzed by several surveys, however it is not trivial to find data with reliable accuracy and precision. There are well-defined and widely used methodologies for the classification of large area images, but in the case of small areas some authors recommend the analog analysis of aerial photos for classification. However, the acquisition of high definition aerial images is not inexpensive. In addition to being a fully manual and labor intensive classification. The present work proposes a methodology for the collection of a quantitative historical database using remote sensing techniques and Digital images, using the NDVI as a comparison criterion. In this work, free images of the Landsat-5, Landsat-8 and Sentinel-2 satellites were used to verify if it is possible to extract reliable information from areas considered small to use the classification supervised by the maximum likelihood method using the ENVI 5.1 software.

Geomorphological Changes of a Migrating Sandbank: Multidecadal Analysis as a Tool for Managing Conflicts in Coastal Use

While beach erosion and sand loss are typically of great concern to the tourism industry, managing rapid morphological changes linked to large amounts of moving sediments is the challenge facing Grado, an important seaside resort in the northern Adriatic, Italy. The cause of the unusual management conflict is the presence of the Mula di Muggia Bank, a nearshore depositional system made up of relict and active migrating sandbanks extending up to 2 km seawards from the touristic beachfront. A reconstruction of the morpho-sedimentary evolution of the coastal system over a 200-year period was done using a large dataset which includes historical cartography, topographic maps, aerial photos and topo-bathymetric surveys. The results show the growth of a significant urban development aimed at creating a tourist destination by occupying the waterfront along fetch-limited coastal tracts with very shallow water and scarce hydrodynamics. Furthermore, a number of sandy dynamic landforms (longshore migrating bars, a bypass corridor, an ebb-tidal delta) and accumulation zones attest to a sediment excess which can be mostly attributed to the eastern river supplies. The progressive constant migration rate of 12.6 my−1 allowed the bank to induce the expansion of the low-energy silty backbarrier environment, characterised by abundant seagrass meadows a short distance directly in front of the tourist beaches of Grado. As a result of historical analysis and more current observations, areas with diverse morphosedimentary features and with varying tourist/recreational, ecological, and conservation values have been identified. These can be considered as basic units for future accurate planning and re-evaluation of coastal management choices to balance environmental protection and tourist use. A soft coastal defence approach is proposed which includes either the preservation of specific environments or the proper use of excess sand for beach nourishment via periodic dredging or sediment bypassing.

Reading an Urban Palimpsest: How the Gradual Loss of an Urban Stream Impacts Urban Form's Connections and Ecosystem Functions

Fluvial reclamation to facilitate urban development leads to culverting, hence, a loss of urban streams. Using the palimpsest analogy, we examine how the Amman Stream in Amman (Jordan) historically provided regulatory and socio-cultural ecosystem services through its socio-spatial (longitudinal, lateral, and vertical) connections. We then explore the impact of the stream's culverting, partially in 1967 then completely in 1997, on these connections and, consequently, on ecosystem services. To overcome data paucity, our methodology relied on constructing spatial data by georeferencing and digitizing aerial photos and satellite images (from 1953, 1975, 1992, and 2000) using ArcGIS. We augmented our data with archival research (historic and contemporary documents and maps), an online survey among Amman's residents, and in situ observations and photography. The results reveal striking contrasts between the historic and contemporary configuration of urban form vis-à-vis the Amman Stream. Throughout its early urban history during the Classical and early Islamic periods, the urban form elements reflected reverence and prudence toward the Amman Stream as manifested in the investment in water infrastructure and the alignment of thoroughfares, civic monuments, and bridges that collectively capitalized on the land relief (the strath) and established strong connections with the Amman Stream, maximizing, in the process, its regulatory and socio-cultural services. In contrast, the contemporary urban form replaced the stream with car-oriented roads, hence, eradicated its regulatory services and replaced its socio-spatial connections with urban socio-economic and cultural fissures. Accordingly, we propose to daylight (de-culvert) the Amman Stream to restore its regulatory and socio-cultural services and its socio-spatial connections. We substantiate the feasibility of daylighting through: (1) morphological analysis that reveals that roads cover most of the stream; (2) the survey's findings that indicate public support; and (3) the cascading benefits for the larger watershed in a water insecure region.

Drought Monitoring in Gresik Regency East Java using Satellite Image Time Series and Google Earth Engine

Gresik is one of the areas with severe drought levels in East Java. This drought disaster caused by low rainfall and the high average surface temperature in an area. These two factors are currently difficult to predict due to uncertain climate change, this is also related to the global warming that is happening. This disaster cannot be completely avoided but can be minimized. This research was conducted to periodically check or time series of droughts by utilizing the Google Earth Engine platform. Drought identification obtained from multitemporal Landsat 8 satellite imagery with the TVDI (Temperature Vegetation Dryness Index) algorithm and field data retrieval in the form of aerial photos using a thermal camera from the DJI Mavic Enterprise Dual Thermal. From this study, it can be monitoring the distribution of drought in the 2015-2020 period in Gresik Regency occurred in 9 sub-districts, there are Wringinanom, Driyorejo, Kedamean, Balongpanggang, Benjeng, Menganti sub-districts as well as several areas in Duduksampeyan, Cerme and Panceng sub-districts. The identification of dry land also correlates well with the rainfall that occurs, namely?100 mm/month, which has low rainfall during drought events.

Miocene to sub-Recent magmatism at the intersection between the Dead Sea Transform and the Ash Shaam volcanic field: evidence from the Yarmouk River gorge and vicinity

The Yarmouk River gorge extends along the Israel–Jordan–Syria border junction. It marks the southern bound of the Irbid–Azraq rift and Harrat Ash Shaam volcanic field at their intersection with the younger Dead Sea Transform plate boundary. During the last ∼13 Ma, the gorge has repeatedly accumulated basaltic units, chronologically named the Lower, Cover, Yarmouk and Raqqad Basalt formations. We examined their origin and distribution through aerial photos, and geological and geophysical evidence. Our results define a southern Golan magmatic province, which includes exposed Miocene (∼13 Ma) basalts, gabbro–diabase intrusions below the gorge and the adjacent Dead Sea Transform valley, and numerous Pliocene–Pleistocene volcanic sources along the gorge. Cover Basalt (∼5.0–4.3 Ma) eruptions formed two adjacent 0–100 m thick plateaus on the transform shoulder before flowing downslope to fill the topographically lower Dead Sea Transform valley with ∼700 m thick basalts. Later incision of the Yarmouk River and displacement along its associated fault divided the plateaus and formed the gorge. The younger Yarmouk (0.8–0.6 Ma) and Raqqad (0.2–0.1 Ma) basalts erupted in the upper part of the gorge from volcanos reported here, and flowed downstream toward the Dead Sea Transform valley. Consequently, eruptions from six phreatic volcanic vents altered the Yarmouk River morphology from sinuous to meandering. Our results associate the ∼13 Ma long southern Golan volcanism with the proposed SW-trending extensional Yarmouk Fault, located east of the Dead Sea Transform. Hence, the Yarmouk volcanism is associated with the ongoing Harrat Ash Shaam activity, which is not directly linked to the displacement along the Dead Sea Transform.

Coal pit lakes in abandoned mining areas in León (NW Spain): characteristics and geoecological significance

Mining activity introduces severe changes in landscapes and, subsequently, in land uses. One of the most singular changes is the existence of pit lakes, which occur in active and, more frequently, abandoned mines. Pit lakes are produced by water table interception when open-pit mines deepen. Their characteristics are highly variable, depending on the type of mine, the environment or the climate. In León province there is a long tradition of coal mining that dates back to the nineteenth century, and hundreds of open pits from the 1970s to 2018 have been opened, producing permanent landscape changes. This work analyses the main parameters, including morphological measurements, depth and pH values obtained from aerial photos and field work, of 76 coal pit lakes more than 30 m in length. The vast majority of these pit lakes were unknown until now and were not included in inventories or maps. The data obtained provide baseline knowledge that will allow, in the future, potential uses (storage of water for various uses, recreational use, wildlife habitat, and geological heritage sites) for these pit lakes and establish their importance as a new geoecological environment.

Airborne Magnetometry to Identify Metallic Debris to Support Dredging and Search Activities at the Brumadinho Disaster Site – A Case Study

This paper describes the procedures and results of an airborne magnetic survey using Unmanned Aerial Vehicle (UAV) conducted to support Search and Rescue (S&R) teams after the failure of a mining tailing dam at the Corrego do Feijão Mine, in the state of Minas Gerais, Southeast Brazil. The accident claimed 270 lives, practically destroying all the mine’s infrastructure. After the accident, the use of a fast, efficient, and cost-effective method to locate preferential sites for the rescue team to work was critical. Due to the difficulty of direct access to the impacted area, and since most of the affected infrastructure consisted of metallic materials, an airborne magnetometer was the logical choice. First, some performance tests were conducted in order to define the survey configurations, such as flight altitude, transect spacing and anomaly’s detectability threshold. After that, task priorities were set, and the survey area divided in small blocks according to their morphological characteristics using aerial photos of the impacted area. The results showed that the system was able to detect all relevant anomalies. The correlation of the anomalies with aerial photogrammetry helped to discard false anomalies, making the whole operation much more efficient. This increased the effectiveness of the S&R teams as well as the planning of the dredging operations by defining the preferential locations for the interventions.