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Significance of storm spatiotemporal variability and movement in flood hydrodynamic modelling
(2024)
This dissertation aims to explore the impact of various storm properties on computational flood modelling and to propose a method for integrating them into flood risk assessment. It focuses on three key areas:
Firstly, it examines within-storm variability, investigating how variations in storm intensity, duration, and spatial distribution affect runoff dynamics. Through a systematic theoretical approach, the study generates synthetic rainfall signals with different hyetograph variabilities and applies them to a hydrodynamic model. The results highlight the significant influence of storm spatiotemporal variability on runoff response, affecting peak discharge, hydrograph shapes, and flooded areas. Temporal variability emerges as particularly dominant, overshadowing spatial variability and other storm properties such as return period and volume. The study emphasizes the spatial dependency of these effects within the drainage network.
Secondly, it investigates the role of storm movement in flood modelling, recognizing its potential to alter runoff dynamics and inundation patterns. By generating synthetic rain hyetographs traversing the catchment area at varying velocities and directions, the study shows that storm movement significantly impacts runoff response and flood extents. Higher storm velocities lead to more pronounced peaks and faster runoff onsets, resulting in larger flooded areas. The direction of storm movement plays a crucial role, with storms aligning with the average stream direction causing the highest peaks and flooded areas. The magnitude of this influence varies depending on the location within the catchment.
Finally, the dissertation introduces a dynamic spatiotemporal rainfall model aimed at preserving storm event properties. Using an event-based approach, dynamic precipitation events are identified and regenerated, ensuring the conservation of storm spatiotemporal variability and movement characteristics. This facilitates the generation of more physically plausible and spatiotemporally coherent precipitation time series. The model prioritizes user accessibility, offering a practical tool for integrating storm properties into flood computation modelling and risk analysis frameworks. By addressing these aspects of storm behaviour, the dissertation contributes to enhancing the accuracy and effectiveness of flood modelling, thereby improving flood risk mitigation efforts.
Despite the continuous effects of natural hazards on cultural heritage and growing body of research on disaster risk assessment, cultural heritage still suffers from the lack of integrated risk assessment methodologies. Within the context of natural hazards, earthquakes need to be differently considered mainly due to the sudden massive destruction without warning and the unpredictability of the exact occurrence time and place. So far, limited sources have been adequately dedicated to developing risk assessment methodologies for cultural heritage. The challenge is to integrate the principles and methods of risk assessment in heritage conservation on one side, and to incorporate particular characteristics of cultural heritage and World Cultural Heritage properties (e.g. the Outstanding Universal Values and associated conditions of authenticity and integrity) into the risk assessment procedure, on the other.
There are numerous cultural properties that have been extremely affected by seismic events, such as the historic city of Bam in Iran. The World Heritage site of ‘Bam and its Cultural Landscape’, as a unique example of a traditional human settlement, is investigated in this research. Because Bam and its Cultural Landscape is located in a high-probability earthquake region and appeared to be highly vulnerable to seismic events, an integrated risk assessment for the property needs to be developed in response to potential earthquakes.
Recognising the challenge, a Cultural Heritage Risk Index for Bam is performed to measure the level of risk by aggregating the risk components, which are ‘hazard’ (earthquakes), ‘exposure’ (significance of the site elements), and ‘vulnerability’ (susceptibility and coping capacity). According to the risk index, an earthquake risk map is generated by applying Geographic Information System (GIS) to demonstrate a common understanding of the level of potential impacts on the property. Furthermore, a multiple impact identification matrix supports determining the potential impacts of an earthquake as well as its related secondary hazards and human-induced threats that need to be addressed in a risk preparedness plan.
The findings of the research emphasis that in addition to the hazard itself, diverse factors associated with the heritage significance, structural susceptibility, and institutional capacity highly influence the level of risk. The outputs of the risk assessment allows determining site-specific risk reduction strategies, particularly seismic susceptibility reduction and coping capacity building. This provides specialists and practitioners from multiple sectors engaged in the protection of (World) cultural heritage with a practical tool to facilitate risk communication and appropriate risk management planning.
Strategic Environmental Assessment in regional land use planning (here: SEA-REP) is a systematic process in Germany, which aims at an optimisation of the integration of environmental policies into decision-making at regional scale. It therefore plays an essential role for the comparison of site alternatives, and the implementation of mitigation and adaptation measures of negative effects of both regional development and climate change. Significant findings and personal experiences gained in an INTERREG project (‛transSEA’) created a fundamental basis for this doctoral research. The main objective was to develop the ‛LUCCA’ indicator system, which is a result of an analysis of land use types, that are increasingly important for effects of global climate change, and should therefore adapt to future conditions with regional land use planning. This system was developed from current German practice of the methodological application of SEA-REP in the core assessment of site-specific impacts on the affected area and impact zone. Main objectives were to integrate spatial effects of climate change into SEA-REP, and to develop a method to make particularly the tendency of physical degradation of natural resources in a region transparent. The research was based on a comprehensive analysis of best practice of SEA and assessment methods applied in German case studies of regional land use planning. Proposed was a a two-tiered environmental baseline- and objective-led approach of impact assessment. Its first tier is a site-specific assessment of significant impacts of regional plan designations and their alternatives. An environmental conflict analysis has the aim to apply assessment thresholds of conflict intensity for each impact factor affecting the importance of assessed components of LUCCA. Results are three classes of conflict intensity, which were determined and can be measured with the help of state indicators, impact indicators and assessment thresholds. 12 LUCCA indicators were defined in connection to regional environmental orientation objectives, environmental components, land uses and further criteria for indicator selection. The second tier is represented by an overall strategic assessment of the regional plan and its designation criteria. This assessment additionally considers positive and cumulative impacts, as well as structural alternatives. The result of the research is a standard concept for environmental orientation objectives, guidance indicators and assessment ranges for the LUCCA indicator system. Regional environmental orientation objectives, which represent outcome values of the future state of environment, were derived from existent environmental quality objectives and environmental quality standards. For each LUCCA indicator mitigation and adaptation measures of regional planning and requirements for tiering to SEA of lower land use planning were proposed. Recommendations for vital and critical action are addressed to competent national and regional authorities of spatial and sector planning. These involve the direct integration of concerns of climate change into SEA-REP, the regional operationalisation of environmental objectives for adaptation to climate change, an improved cooperation between spatial and sector planners concerned with the future use of land and resources, and, last but not least, an involvement of the public in the setting of regional objectives for the future state of a region’s environment. Recommendations for the competent national and federal ministries are the integration of substantial standards into legislation, the setting of binding standards for a stricter reduction of land consumption, the determination of clear responsibilities and activities at all planning levels, and the release of guidance for effective regional land use planning practice that enhances adaptation to climate change. The main recommendations for European regional planning bodies are to establish regional environmental objective concepts for SEA-REP, update regional environmental data profiles, apply the SEA-REP+LUCCA indicator system, develop a tiered decision-support system, challenge conventional regional planning, improve cooperation with sector planning and involve the public in the development of adaptation strategies. A recommended adaptation task at regional planning level is the designation of strictly safeguarded priority areas with specific functions of land uses for the mitigation of negative effects of climate change. Such priority areas, which should be area-specifically defined in a regional land use map, should be linked to the implementation of binding adaptation measures in lower land use planning and at project level. An operationalisation of proposed assessment steps will be necessary for the regional-specific geographic and bio-physical conditions of the EU regions. The thesis concludes with future research needs and an outlook on the potential future role of SEA-REP. A clear responsibility of the future tasks of SEA-REP and LUCCA was recognised as a formal driving force for adaptation of land use to effects of climate change. Improved knowledge on spatial effects of climate change and vulnerability assessments will be required for an effective revision and application of SEA-REP and LUCCA. SEA should gain further importance in a transparent and participative decision-making. Environmental concerns and the protection of LUCCA will have to gain more weight, if the significance of danger and harm, caused by effects of climate change and anthropogenic land degradation, shall be mitigated now and in the future.
Die in der Versorgungslogistik internationaler Automobilhersteller in China immanenten Risiken werden bislang bei versorgungslogistischen Entscheidungen nicht systematisch berücksichtigt. Um die Berücksichtigung dieser Risiken zu ermöglichen, wird ein empirisch entwickeltes Risikobewertungskonzept vorgestellt, welches an die verschiedenen Entscheidungssituationen anpassbar ist. Dieses besteht aus einem Risikobewertungsprozess und einer vorgelagerten Situationsanalyse, mit der geeignete Verfahren zur Konfiguration des Risikobewertungsprozesses identifiziert werden können. Der Risikobewertungsprozess, der alle Risiken mit einem Geldwert belegt, besteht aus fünf Schritten: 1) es werden Verteilungen der Risikofaktoren bestimmt; 2) deren Wirkung auf die Abweichung der sieben Zielgrößen der Versorgungslogistik werden ermittelt: 3) die Wirkung dieser Zielgrößenabweichung für das Unternehmen werden in Geldeinheiten ermittelt; 4) die Wirkung der Einzelrisiken werden aggregiert; 5) das Risikobewertungsergebnis wird visualisiert. Die so ermittelten Risiken werden nach der jeweiligen Abweichung von einem der sieben eingeführten versorgungslogistischen Zielgrößen benannt. Die diesem Risikobewertungsprozess vorgeschaltete Situationsanalyse unterscheidet alle versorgungslogistischen Entscheidungen in vier Basistypen, je nach Gewichtigkeit der Entscheidung für das Unternehmen und der prozess- und informationsbezogenen Qualität des Entscheidungsprozesses. Für jeden dieser vier Basistypen sind empirisch aufgenommene Anforderungen an die Risikobewertung hinterlegt, die zur Konfiguration des Risikobewertungsprozesses mit den optimal geeigneten Risikobewertungsverfahren verwendet werden. Eine Evaluation des Konzeptes zur Situationsanalyse und Konfiguration des Risikobewertungsprozesses, erfolgt anhand einer empirischen Fallstudie.