Floodplain rehabilitation projects in Hungary: Case studies from the Danube, Tisza, Körös and Drava rivers

Floodplains along regulated rivers often suffer from serious environmental degradation. River and floodplain rehabilitation measures along the major rivers of Hungary are motivated by two objectives: to inrease the floodwater retention capacity of floodplains (also beyond the dykes) and to improve the ecological conditions of floodplain habitats (with special regard to oxbow lakes). In this paper reports and documents mostly written in Hungarian are presented for the international public on river and floodplain rehabilitation efforts. Examples for the water management objective are cited from the Tisza and Körös Rivers, while interventions promoting the second, nature conservation (and also forestry and agriculture), aim are mentioned from the Danube and Drava Rivers. A common characteristic of the case studies is that they apply ’hard engineering’ solutions to environmental problems. Although water availability in the Szigetköz floodplain has substantially improved after the building of the bottom weir, the efficiency of the recently implemented engineering measures (the emergency reservoirs along the Tisza and water replenishment structures along the Drava) is too early to judge

Object-based approach for urban land cover mapping using high spatial resolution data

This paper deals with object-oriented image analysis applied for an urban area. Very high-resolution images in conjunction with object-oriented image analysis have been used for land cover detection. Using the eCognition software with object-oriented methods, not only the spectral information but also the shape, compactness and other parameters can be used to extract meaningful objects. The spectral and geometric diversity of urban surfaces is a very complex research issue. It is the main reason why additional information is needed to improve the outcome of classification. The most consistent and relevant characteristic of buildings is their height. Therefore, elevation data (converted from LIDAR data) are used for building extraction, segmentation and classification. The study deals with the problem, how to determine the most appropriate parameters of segmentation, feature extraction and classification methods. The data extraction includes two phases, the first part consists the following steps: data pre-processing, rule set development, multi-scale image segmentation, the definition of features used to map land use, classification based on rule set and accuracy evaluation. The second part of the data process based on classical raster analysis GIS tools like focal and zonal function

Csapadék-árhullám reakcióidők meghatározása pécsi vízfolyások esetében

A Mecsek déli lejtőjén fekvő Pécs tagolt domborzattal és a vízzáró felszínek magas arányával jellemezhető. A spontán és nem megfelelően ellenőrzött városfejlesztés következtében a csatornahálózat és a csapadékvíz elvezetése nem szakszerűen megoldott a városban, ami jelentős elöntéseket és károkat okoz főként nagyintenzitású csapadékokat követően. A jelen kutatás célja a csapadéktöbbletből származó károkra való felkészülés elősegítése, pontosan a védekezésre rendelkezésre álló idő meghatározása a Pécsi-víz részvízgyűjtői esetében. Az összegyülekezési időket a 2014-ben öt vízmércéből és 12 csapadékszenzorból, valamint léghőmérséklet mérőkből, talajnedvesség-szenzorokból álló hidrometeorológiai monitoringhálózat adatai szolgáltatták. Eredményeink alapján az árhullámok reakcióideje függvényszerű összefüggést mutatott a csapadékesemények átlagos és maximális intenzitásával. A reakcióidő a vizsgált események 50 százalékában kevesebb, mint egy óra volt, a legrövidebb reakcióidő esetében pedig 5 percet regisztráltunk. Ugyan évszakos összefüggést nem sikerült megállapítani a csapadékintenzitás és a reakcióidők között, azonban alapvetően a nyári és az őszi csapadékesemények rövidebb reakcióidővel rendelkeztek, mint a téli és tavaszi események. Eredményeink jó alapot nyújthatnak hidrometeorológiai monitoringhálózatok tervezéséhez, valamint adatot szolgáltathatnak a városgazdálkodási vállalat (BIOKOM Nonprofit Kft.) számára a védekezési időket illetően, valamint a csapadék-lefolyás modellek pontosabb parametrizálásához

Surface Deformation Monitoring and Risk Mapping in the Surroundings of the Solotvyno Salt Mine (Ukraine) between 1992 and 2021

The historical Ukrainian rock-salt mining town of Solotvyno and its environmentally related problems are well-known. A complex monitoring system is needed to evaluate the current situation in order to revitalize the investigated area. In addition to other risks, surface deformation due to undermining is one of the major risks endangering building infrastructure in the inhabited area of the town. These processes are well-known in the area, and damages caused by the surface movement are often recognized. Measurement of the process’s intensity and identification of the impacted area are crucial for any revitalization work. Information on these processes is the most important element of the hazard management and spatial-developmental planning of the town. This study aimed to characterize the long-term surface deformation processes and to identify the spatial and temporal trends and changes of these processes to assist spatial planning. The first step was to understand the surface deformation history from 1992. An InSAR-based assessment of the surface displacement of the undermined Solotvyno area was performed using data from three satellites, namely the ERS, Envisat, and the Sentinel-1, covering the time period between 1992 and 2021. The derived quantitative analysis indicated an intensive surface displacement and subsidence over the mining area. However, these displacements have not been even in the last 30 years of the investigation. The identification of the stabilized areas and recently started movements indicated the dislocation of the processes, which requires adequate actions for geohazard management and strategic planning. The demonstrated technology (InSAR) has the potential to set up an appropriate alarm system and provides an automated mechanism for continuous risk detection. A complex systems development is able to significantly reduce the geohazards over the unstable built-up zones

Nationwide, Operational Sentinel-1 Based InSAR Monitoring System in the Cloud for Strategic Water Facilities in Hungary

The intensive development of both interferometric technology and sensors in recent years allows Interferometric Synthetic Aperture Radar (InSAR)-based applications to be accessible to a growing number of users. InSAR-based services now cover entire countries and soon even the whole of Europe. These InSAR systems require massive amounts of computer processing power and significant time to generate a final product. Most, if not all, of these projects have a limited “monitoring component”, aimed at historical analysis but are rarely, if ever, updated. Consequently, the results do not necessarily meet every purpose or specific user requirement. It is now clear that the increasing computing capacity and big data provided by the sensors have initiated the development of new InSAR services. However, these systems are only useful when linked to specific real-world operational problems. Continuous monitoring of a country’s ageing water management infrastructure has become an increasingly critical issue in recent years, in addition to the threats posed by climate change. Our article provides a comprehensive overview of a nationwide, dedicated, operational InSAR application, which was developed to support the operational work of the Hungarian Disaster Management Service (HDMS). The objective was to provide monthly monitoring of 63 water facilities, including 83 individual objects, distributed throughout Hungary, in combination with the development of a near real-time warning system. Our work involved the compilation of a completely new InSAR System as a Service (SaaS) which incorporates user requirements, preparatory work, the compilation of the Sentinel-1 automatic processing pipeline, the installation of corner reflectors, a special early warning system, and a dedicated user interface. The developed system can automatically start to evaluate the S1 measurements within 24 h of downloading the data into the system storage forward the results toward the warning system before the next image arrives. Users are provided with detailed information on the stability of 70% of the 83 water facility objects monitored through the dedicated user interface. The additional early warning system currently operates as a preliminary “spatial decision support system”, but the HDMS is willing to make it fully operational over the next few years