Gerasimos Pavlogeorgatos

Coastline Zones Identification and 3D Coastal Mapping Using UAV Spatial Data

Spatial data acquisition is a critical process for the identification of the coastline and coastal zones for scientists involved in the study of coastal morphology. The availability of very high-resolution digital surface models (DSMs) and orthophoto maps is of increasing interest to all scientists, especially those monitoring small variations in the earth’s surface, such as coastline morphology. In this article, we present a methodology to acquire and process high resolution data for coastal zones acquired by a vertical take off and landing (VTOL) unmanned aerial vehicle (UAV) attached to a small commercial camera. The proposed methodology integrated computer vision algorithms for 3D representation with image processing techniques for analysis. The computer vision algorithms used the structure from motion (SfM) approach while the image processing techniques used the geographic object-based image analysis (GEOBIA) with fuzzy classification. The SfM pipeline was used to construct the DSMs and orthophotos with a measurement precision in the order of centimeters. Consequently, GEOBIA was used to create objects by grouping pixels that had the same spectral characteristics together and extracting statistical features from them. The objects produced were classified by fuzzy classification using the statistical features as input. The classification output classes included beach composition (sand, rubble, and rocks) and sub-surface classes (seagrass, sand, algae, and rocks). The methodology was applied to two case studies of coastal areas with different compositions: a sandy beach with a large face and a rubble beach with a small face. Both are threatened by beach erosion and have been degraded by the action of sea storms. Results show that the coastline, which is the low limit of the swash zone, was detected successfully by both the 3D representations and the image classifications. Furthermore, several traces representing previous sea states were successfully recognized in the case of the sandy beach, while the erosion and beach crests were detected in the case of the rubble beach. The achieved level of detail of the 3D representations revealed new beach characteristics, including erosion crests, berm zones, and sand dunes. In conclusion, the UAV SfM workflow provides information in a spatial resolution that permits the study of coastal changes with confidence and provides accurate 3D visualizations of the beach zones, even for areas with complex topography. The overall results show that the presented methodology is a robust tool for the classification, 3D visualization, and mapping of coastal morphology.

Monitoring priority substances of directives 76/464/EEC and 2000/60/EC in Greek water bodies.

The priority substances of List I, 76/464/EEC Directive, some of which belong to the new Water Framework Directive 2000/60/EC, have been monitored in the surface waters of Greece through the developed network of 53 sampling stations. The analytical methods used for the determination of these substances included Purge and Trap-Gas chromatography-Mass spectrometry for volatile and semivolatile organic compounds, Gas Chromatography-Electron Capture Detection for organochlorine insecticides, High Performance Liquid Chromatography for pentachlorophenol and Atomic Absorption Spectrometry for metals. The results have shown the presence of several priority substances in Greek surface waters, in most cases at concentrations well below the regulatory limits. However, non-compliance was observed for a limited number of compounds. The monitoring network and the analytical determinations have to be expanded to more water bodies and more priority substances, in order to safeguard the quality of Greek surface waters.

Examination of mercury's effects during the process of the activated sludge

The objectives of this report are: (a) the study of the mercury contaminated wastewater input effects at the activated sludge process in an activated sludge pilot plant and (b) the estimation of the removal ability of mercurys input, at different concentrations, from the activated sludge pilot plant. The concentration of inorganic mercury at the inlet of the plant varied from 0 to 100 μg/l HgCl2. The most important physical, chemical and biological parameters of the pilot plant were measured at least 4 times a day. Consequently, it was possible to describe, in a more detailed way, the effect that mercurys input had on the activated sludge procedure and to point at the most critical fluctuations of mercurys removal ability from the pilot plant.

Modelling Archaeological and Geospatial Information for Burial Site Prediction, Identification and Management

The application of technologies in humanities and specifically in Archaeology over the past recent years has yielded important expertise that can be successfully exploited by both Archaeological Research and Cultural Heritage Management. This study presents a general methodology for designing, developing and implementing predictive modelling for identifying sites of archaeological interest. The methodology is based on documented archaeological data and geographical factors, geospatial analysis and predictive modelling into one consistent workflow. The model was tested extensively and was validated using a commonly used predictive gain. The results and the evaluation of the model proved the efficiency of its predictive ability in providing answers to a series of questions related to Archaeological Research issues and Cultural Heritage Management.

Resilience of Touristic Island Beaches Under Sea Level Rise: A Methodological Framework

ABSTRACT This contribution addresses the need for a simple model for managers to employ when planning strategies for the management of touristic beaches under sea level rise. A methodological framework was developed and tested in two Aegean archipelago islands (Lesvos and Rhodes, Greece). The scheme can represent the status of touristic island beaches, based on easily obtained variables/indicators and projections of beach erosion/retreat under different scenarios of mean sea level rise (MSLR) and extreme events. Information on beach geomorphological characteristics, environmental setting, water quality, management, and services (such as those used in the “Blue Flag” classification) was collated/collected and beach erosion/retreat due to CV & C was estimated through suitable ensembles of cross-shore (1-D) morphodynamic models. A Strength-Weaknesses-Opportunities-Threats (SWOT) framework was employed to assist in the selection of indicators and multicriteria analysis used to optimize indicator weights and rank beaches according to their sustainability under sea level rise. Implementation of the framework at the two islands has shown that: the majority of Lesvos and Rhodes beaches (82% of a total of 217 beaches and 58% of a total of 97 beaches, respectively) can be classified as beaches with no, or minimal, human interference, suggesting that under environmentally sound coastal management further touristic development might be afforded; there could be very significant effects of the sea level rise on the carrying and buffering capacities of the most developed (“Blue Flag”) beaches, with some expected even under conservative projections to be completely eroded by 2100, unless technical adaptation measures are taken; and using the proposed framework, touristic beaches can be rapidly ranked in terms of their resilience to sea level rise and their development potential, allowing prioritization of effective management responses.

Marine spatial planning in Cyprus

Marine Spatial Planning (MSP), which is in concept similar to land-use planning, is a public process by which the relevant Member State’s authorities analyse and organise human activities in marine areas to achieve ecological, economic and social objectives. MSP aims to promote sustainable growth of maritime economies, sustainable development of marine areas and sustainable use of marine resources. This paper highlights the importance of MSP and provides basic outcomes of the main European marine development. The already successful MSP plans can provide useful feedback and guidelines for other countries that are in the process of implementation of an integrated MSP, such as Cyprus. This paper presents part of the MSP project, of which 80% funded by the European Regional Development Fund (ERDF) and 20% from national contribution. An overview of the project is presented, including data acquisition, methodology and preliminary results for the implementation of MSP in Cyprus.

Ecosystem Services and spatial planning in sensitive and vulnerable coastal areas: a case study in the Aegean Sea.

Ecosystem services include natural processes and biotic resources that can significantly contribute to environmental sustainability and fulfill human life. Oxygen production, transformation of organic matter, waste assimilation, cleansing, biogeochemical processes supporting recycling of organic matter and detoxification of pollutants as well as highly valued landscapes and seascapes are among the most significant ecosystem services. In addition, protection, production, delivery of goods and services from the natural environment are highly valued by the community. In the marine environment biological resources (fisheries and aquaculture), installations for energy production based on renewable sources and recreational use of the coastal environment are the main benefits to humans from the point of view of biological services. Use of the coastal waters as a dispersion field for sewage and industrial effluents should also be valued as an ecosystem service. However, many of those activities are conflicting and therefore implementation of marine spatial planning practices should be adopted. This is particularly important in sensitive and vulnerable areas like the Aegean marine ecosystems and the Aegean Islands. In the present work, the main ecosystem services in the Aegean are reviewed and methods for spatial planning scenarios focusing on blue growth based on ecosystem services are proposed for the Northern and Southern Aegean Regions.

Effect of mercury-contaminated wastewater on activated sludge suspended solids size distribution

The primal purpose of this research project is to examine the size distribution of the Suspended Solids (SS) of an activated sludge pilot plant, under different operational conditions and during the introduction of wastewater contaminated with mercury of different concentrations (10–100 µg/L Hg(NO3)2). While the experiment was being conducted, the most important parameters of the pilot plant (COD, TOC, MLSS, SS, NH4, PO4, total number of bacteria – coccoids and rods, pH, DO, T etc.) were measured; this fact led to the inference of conclusions that connect the distribution of the size of the SS with those parameters. The main conclusions of this research work are: (a) the important interaction of the removal ability of the organic loading of the plant and the size distribution of the SS at the aeration tank and the outlet of the plant and (b) the input of the mercury-contaminated wastewater at the plant affects the size distribution of the SS at the aeration tank. The second conclusion probably indicates a possible way that microorganisms of the aeration tank react to the introduction of mercury.

DETERMINATION OF CADMIUM IN THE SURFACE WATERS OF NORTHERN GREECE

Northern Greece is a part of the country with great agricultural and industrial activity and the estimation of the pollution of its rivers and lakes is very important. The objective of this study is the determination of cadmium (Cd) in the surface waters of Northern Greece. The sampling period lasted 18 months, and samples were collected every 3 months. Sampling sites included 4 rivers (Axios, Strimonas, Nestos, Evros) and 5 lakes (Vegoritida, Volvi, Vistonida, Mikri Prespa, Megali Prespa). Cd was determined with Graphite Furnace Atomic Absorption Spectrometry (GFAAS). The results obtained show that the levels of Cd concentrations are lower than the qualitative target levels of EEC.