| 1. |
- AghaKouchak, Amir, et al.
(författare)
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Anthropogenic Drought : Definition, Challenges, and Opportunities
- 2021
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Ingår i: Reviews of geophysics. - : John Wiley & Sons. - 8755-1209 .- 1944-9208. ; 59:2
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Forskningsöversikt (refereegranskat)abstract
- Traditional, mainstream definitions of drought describe it as deficit in water-related variables or water-dependent activities (e.g., precipitation, soil moisture, surface and groundwater storage, and irrigation) due to natural variabilities that are out of the control of local decision-makers. Here, we argue that within coupled human-water systems, drought must be defined and understood as a process as opposed to a product to help better frame and describe the complex and interrelated dynamics of both natural and human-induced changes that define anthropogenic drought as a compound multidimensional and multiscale phenomenon, governed by the combination of natural water variability, climate change, human decisions and activities, and altered micro-climate conditions due to changes in land and water management. This definition considers the full spectrum of dynamic feedbacks and processes (e.g., land-atmosphere interactions and water and energy balance) within human-nature systems that drive the development of anthropogenic drought. This process magnifies the water supply demand gap and can lead to water bankruptcy, which will become more rampant around the globe in the coming decades due to continuously growing water demands under compounding effects of climate change and global environmental degradation. This challenge has de facto implications for both short-term and long-term water resources planning and management, water governance, and policymaking. Herein, after a brief overview of the anthropogenic drought concept and its examples, we discuss existing research gaps and opportunities for better understanding, modeling, and management of this phenomenon.
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| 2. |
- Albertini, Cinzia, et al.
(författare)
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Socio-Hydrological Modelling : The Influence of Reservoir Management and Societal Responses on Flood Impacts
- 2020
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Ingår i: Water. - : MDPI AG. - 2073-4441. ; 12:5
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Tidskriftsartikel (refereegranskat)abstract
- Over the last few years, several socio-hydrological studies have investigated the risk dynamics generated by the complex interactions between floods and societies, with a focus on either changing reservoir operation rules or raising levees. In this study, we propose a new socio-hydrological model of human-flood interactions that represents both changes in the reservoir management strategies and updating of the levee system. Our model is applied to simulate three prototypes of floodplain management strategies to cope with flood risk: green systems, in which societies resettle outside the flood-prone area; technological systems, in which societies implement structural measures, such as levees; and green-to-techno systems, in which societies shift from green to technological approaches. Floodplain dynamics are explored simulating possible future scenarios in the city of Brisbane, Australia. Results show that flood risk is strongly influenced by changes in flood and drought memory of reservoir operators, while risk-awareness levels shape the urbanisation of floodplains. Furthermore, scenarios of more frequent and higher magnitude events prove to enhance social flood memory in green systems, while technological systems experience much higher losses. Interestingly, green-to-techno systems may also evolve toward green floodplain management systems in response to large losses and technical/economical unfeasibility of larger structural measures.
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| 3. |
- Alfieri, Lorenzo, et al.
(författare)
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Increasing flood risk under climate change: a pan-European assessment of the benefits of four adaptation strategies
- 2016
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Ingår i: Climatic Change. - : Springer Science and Business Media LLC. - 0165-0009 .- 1573-1480. ; 136:3, s. 507-521
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Tidskriftsartikel (refereegranskat)abstract
- Future flood risk in Europe is likely to increase due to a combination of climatic and socio-economic drivers. Effective adaptation strategies need to be implemented to limit the impact of river flooding on population and assets. This research builds upon a recently developed flood risk assessment framework at European scale to explore the benefits of adaptation against extreme floods. The effect of implementing four different adaptation measures is simulated in the modeling framework. Measures include the rise of flood protections, reduction of the peak flows through water retention, reduction of vulnerability and relocation to safer areas. Their sensitivity is assessed in several configurations under a high-end global warming scenario over the time range 1976-2100. Results suggest that the future increase in expected damage and population affected by river floods can be compensated through different configurations of adaptation measures. The adaptation efforts should favor measures targeted at reducing the impacts of floods, rather than trying to avoid them. Conversely, adaptation plans only based on rising flood protections have the effect of reducing the frequency of small floods and exposing the society to less-frequent but catastrophic floods and potentially long recovery processes.
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| 4. |
- Alfonso, L., et al.
(författare)
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Probabilistic Flood Maps to support decision-making : Mapping the Value of Information
- 2016
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Ingår i: Water resources research. - 0043-1397 .- 1944-7973. ; 52:2, s. 1026-1043
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Tidskriftsartikel (refereegranskat)abstract
- Floods are one of the most frequent and disruptive natural hazards that affect man. Annually, significant flood damage is documented worldwide. Flood mapping is a common preimpact flood hazard mitigation measure, for which advanced methods and tools (such as flood inundation models) are used to estimate potential flood extent maps that are used in spatial planning. However, these tools are affected, largely to an unknown degree, by both epistemic and aleatory uncertainty. Over the past few years, advances in uncertainty analysis with respect to flood inundation modeling show that it is appropriate to adopt Probabilistic Flood Maps (PFM) to account for uncertainty. However, the following question arises; how can probabilistic flood hazard information be incorporated into spatial planning? Thus, a consistent framework to incorporate PFMs into the decision-making is required. In this paper, a novel methodology based on Decision-Making under Uncertainty theories, in particular Value of Information (VOI) is proposed. Specifically, the methodology entails the use of a PFM to generate a VOI map, which highlights floodplain locations where additional information is valuable with respect to available floodplain management actions and their potential consequences. The methodology is illustrated with a simplified example and also applied to a real case study in the South of France, where a VOI map is analyzed on the basis of historical land use change decisions over a period of 26 years. Results show that uncertain flood hazard information encapsulated in PFMs can aid decision-making in floodplain planning.
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| 5. |
- Ali, A. Md, et al.
(författare)
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Assessing the impact of different sources of topographic data on 1-D hydraulic modelling of floods
- 2015
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Ingår i: Hydrology and Earth System Sciences. - : Copernicus GmbH. - 1027-5606 .- 1607-7938. ; 19:1, s. 631-643
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Tidskriftsartikel (refereegranskat)abstract
- Topographic data, such as digital elevation models (DEMs), are essential input in flood inundation modelling. DEMs can be derived from several sources either through remote sensing techniques (spaceborne or airborne imagery) or from traditional methods (ground survey). The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), the Shuttle Radar Topography Mission (SRTM), the light detection and ranging (lidar), and topographic contour maps are some of the most commonly used sources of data for DEMs. These DEMs are characterized by different precision and accuracy. On the one hand, the spatial resolution of low-cost DEMs from satellite imagery, such as ASTER and SRTM, is rather coarse (around 30 to 90 m). On the other hand, the lidar technique is able to produce high-resolution DEMs (at around 1 m), but at a much higher cost. Lastly, contour mapping based on ground survey is time consuming, particularly for higher scales, and may not be possible for some remote areas. The use of these different sources of DEM obviously affects the results of flood inundation models. This paper shows and compares a number of 1-D hydraulic models developed using HEC-RAS as model code and the aforementioned sources of DEM as geometric input. To test model selection, the outcomes of the 1-D models were also compared, in terms of flood water levels, to the results of 2-D models (LISFLOOD-FP). The study was carried out on a reach of the Johor River, in Malaysia. The effect of the different sources of DEMs (and different resolutions) was investigated by considering the performance of the hydraulic models in simulating flood water levels as well as inundation maps. The outcomes of our study show that the use of different DEMs has serious implications to the results of hydraulic models. The outcomes also indicate that the loss of model accuracy due to re-sampling the highest resolution DEM (i.e. lidar 1 m) to lower resolution is much less than the loss of model accuracy due to the use of lowcost DEM that have not only a lower resolution, but also a lower quality. Lastly, to better explore the sensitivity of the 1-D hydraulic models to different DEMs, we performed an uncertainty analysis based on the GLUE methodology.
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| 6. |
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| 7. |
- Biella, Riccardo, et al.
(författare)
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Thinking systemically about climate services: Using archetypes to reveal maladaptation
- 2024
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Ingår i: Climate Services. - : Elsevier BV. - 2405-8807. ; 34
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Tidskriftsartikel (refereegranskat)abstract
- Developing and implementing climate adaptation measures in complex socio-ecological systems can lead to unintended consequences, especially when those systems are undergoing rapid hydro-climatic and socio-economic change. In these dynamic contexts, a systemic approach can make the difference between adaptive and maladaptive outcomes. This paper focuses on the use of climate services, often touted as no-regret solutions, and their potential to generate maladaptation. We explored the interactions between climate services and adaptation/maladaptation across five case studies affected by different types of natural hazards and characterized by a range of hydro-climatic and socio-economic conditions. Using system archetypes, we show how climate services can play a role in both producing and preventing maladaptation. The dynamics explored through system archetypes are: i) “fixes that fail”, where short-sighted solutions fail to address the root causes of a problem; ii) “band aid solutions”, where the benefits brought about in the short-term come at the expenses of delaying long-term adaptive actions; and iii) “success to the successful”, where some groups increasingly benefit from climate services at the expenses of other groups. We demonstrate how these dynamics constitute maladaptive processes, as well as identifying the tools and theories that can be used in this type of assessment. Finally, we provide a framework and recommendations to guide the ex-ante assessment of maladaptation risk when designing and implementing climate services.
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| 8. |
- Blösch, Günter, et al.
(författare)
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Twenty-three unsolved problems in hydrology (UPH) - a community perspective
- 2019
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Ingår i: Hydrological Sciences Journal. - : Informa UK Limited. - 0262-6667 .- 2150-3435. ; 64:10, s. 1141-1158
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Tidskriftsartikel (refereegranskat)abstract
- This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through online media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focused on the process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come.
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| 9. |
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| 10. |
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| 11. |
- Brandimarte, Luigia, et al.
(författare)
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Relation Between the North-Atlantic Oscillation and Hydroclimatic Conditions in Mediterranean Areas
- 2011
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Ingår i: Water Resources Management. - : Springer Science and Business Media LLC. - 0920-4741 .- 1573-1650. ; 25:5, s. 1269-1279
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Tidskriftsartikel (refereegranskat)abstract
- Mediterranean basins are known for their susceptibility to water stress conditions resulting from a reduction in winter-season precipitation. This region is also prone to the effects of the North Atlantic Oscillation (NAO), a large-scale climatic pattern associated with a displacement of air mass between the arctic and the subtropical Atlantic. Even though previous studies have demonstrated the impact of the NAO on winter climate conditions in Europe and Northern Africa, it is still unclear to what extent the NAO is related to hydroclimatic patterns in Mediterranean areas and whether it can explain its recent drought history. To this end, this study investigates the interdependence between the NAO and winter precipitation, river flow and temperature in two Mediterranean regions: Southern Italy and Nile Delta (Egypt). The outcomes show the presence of significant connections between the NAO, winter rainfall and river discharge.
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| 12. |
- Brandimarte, Luigia, et al.
(författare)
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Uncertainty in design flood profiles derived by hydraulic modelling
- 2012
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Ingår i: Hydrology Research. - : IWA Publishing. - 0029-1277 .- 2224-7955 .- 1998-9563. ; 43:6, s. 753-761
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Tidskriftsartikel (refereegranskat)abstract
- The scientific literature has widely shown that hydraulic modelling is affected by many sources of uncertainty (e.g. model structure, input data, model parameters). However, when hydraulic models are used for engineering purposes (e.g. flood defense design), there is still a tendency to make a deterministic use of them. More specifically, the prediction of flood design profiles is often based on the outcomes of a calibrated hydraulic model. Despite the good results in model calibration, this prediction is affected by significant uncertainty, which is commonly considered by adding a freeboard to the simulated flood profile. A more accurate approach would require an explicit analysis of the sources of uncertainty affecting hydraulic modelling and design flood estimation. This paper proposes an alternative approach, which is based on the use of uncertain flood profiles, where the most significant sources of uncertainty are explicitly analyzed. An application to the Po river reach between Cremona and Borgoforte (Italy) is used to illustrate the proposed framework and compare it to the traditional approach. This paper shows that the deterministic approach underestimates the design flood profile and questions whether the freeboard, often arbitrarily defined, might lead to a false perception of additional safety levels.
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| 13. |
- Breinl, Korbinian, et al.
(författare)
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Can weather generation capture precipitation patterns across different climates, spatial scales and under data scarcity?
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Stochastic weather generators can generate very long time series of weather patterns, which are indispensable in earth sciences, ecology and climate research. Yet, both their potential and limitations remain largely unclear because past research has typically focused on eclectic case studies at small spatial scales in temperate climates. In addition, stochastic multi-site algorithms are usually not publicly available, making the reproducibility of results difficult. To overcome these limitations, we investigated the performance of the reduced-complexity multi-site precipitation generator TripleM across three different climatic regions in the United States. By resampling observations, we investigated for the first time the performance of a multi-site precipitation generator as a function of the extent of the gauge network and the network density. The definition of the role of the network density provides new insights into the applicability in data-poor contexts. The performance was assessed using nine different statistical metrics with main focus on the inter-annual variability of precipitation and the lengths of dry and wet spells. Among our study regions, our results indicate a more accurate performance in wet temperate climates compared to drier climates. Performance deficits are more marked at larger spatial scales due to the increasing heterogeneity of climatic conditions.
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| 14. |
- Breinl, Korbinian, et al.
(författare)
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Extreme dry and wet spells face changes in their duration and timing
- 2020
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Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 15:7
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Tidskriftsartikel (refereegranskat)abstract
- Dry spells are sequences of days without precipitation. They can have negative implications for societies, including water security and agriculture. For example, changes in their duration and within-year timing can pose a threat to food production and wildfire risk. Conversely, wet spells are sequences of days with precipitation above a certain threshold, and changes in their duration and within-year timing can impact agriculture, flooding or the prevalence of water-related vector-borne diseases. Here we assess changes in the duration and within-year timing of extreme dry and wet spells over 60 years (1958-2017) using a consistent global land surface precipitation dataset of 5093 rain gauge locations. The dataset allowed for detailed spatial analyses of the United States, Europe and Australia. While many locations exhibit statistically significant changes in the duration of extreme dry and wet spells, the changes in the within-year timing are less often significant. Our results show consistencies with observations and projections from state-of-the-art climate and water resources research. In addition, we provide new insights regarding trends in the timing of extreme dry and wet spells, an aspect being equally important for possible future implications of extremes in a changing climate, which has not yet received the same level of attention and is characterized by larger uncertainty.
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| 15. |
- Breinl, Korbinian, et al.
(författare)
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Space-time disaggregation of precipitation and temperature across different climates and spatial scales
- 2019
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Ingår i: Journal of Hydrology. - : ELSEVIER SCIENCE BV. - 2214-5818. ; 21, s. 126-146
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Tidskriftsartikel (refereegranskat)abstract
- Study region: This study focuses on two study areas: the Province of Trento (Italy; 6200 km(2)), and entire Sweden (447000km(2)). The Province of Trento is a complex mountainous area including subarctic, humid continental and Tundra climates. Sweden, instead, is mainly dominated by a subarctic climate in the North and an oceanic climate in the South. Study focus: Hydrological predictions often require long weather time series of high temporal resolution. Daily observations typically exceed the length of sub-daily observations, and daily gauges are more widely available than sub-daily gauges. The issue can be overcome by disaggregating daily into sub-daily values. We present an open-source tool for the non-parametric space-time disaggregation of daily precipitation and temperature into hourly values called spatial method of fragments (S-MOF). A large number of comparative experiments was conducted for both S-MOF and MOF in the two study regions. New hydrological insights for the region: Our experiments demonstrate the applicability of the univariate and spatial method of fragments in the two temperate/subarctic study regions where snow processes are important. S-MOF is able to produce consistent precipitation and temperature fields at sub-daily resolution with acceptable method related bias. For precipitation, although climatologically more complex, S-MOF generally leads to better results in the Province of Trento than in Sweden, mainly due to the smaller spatial extent of the former region.
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| 16. |
- Buchecker, M., et al.
(författare)
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The role of risk perception in making flood risk management more effective
- 2013
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Ingår i: Natural hazards and earth system sciences. - : Copernicus GmbH. - 1561-8633 .- 1684-9981. ; 13, s. 3013-3030
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Tidskriftsartikel (refereegranskat)abstract
- Over the last few decades, Europe has suffered from a number of severe flood events and, as a result, there has been a growing interest in probing alternative approaches to managing flood risk via prevention measures. A literature review reveals that, although in the last decades risk evaluation has been recognized as key element of risk management, and risk assessment methodologies (including risk analysis and evaluation) have been improved by including social, economic, cultural, historical and political conditions, the theoretical schemes are not yet applied in practice. One main reason for this shortcoming is that risk perception literature is mainly of universal and theoretical nature and cannot provide the necessary details to implement a comprehensive risk evaluation. This paper therefore aims to explore a procedure that allows the inclusion of stakeholders' perceptions of prevention measures in risk assessment. It proposes to adopt methods of risk communication (both one-way and two-way communication) in risk assessment with the final aim of making flood risk management more effective. The proposed procedure not only focuses on the effect of discursive risk communication on risk perception, and on achieving a shared assessment of the prevention alternatives, but also considers the effects of the communication process on perceived uncertainties, accepted risk levels, and trust in the managing institutions.The effectiveness of this combined procedure has been studied and illustrated using the example of the participatory flood prevention assessment process on the Sihl River in Zurich, Switzerland. The main findings of the case study suggest that the proposed procedure performed well, but that it needs some adaptations for it to be applicable in different contexts and to allow a (semi-) quantitative estimation of risk perception to be used as an indicator of adaptive capacity.
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| 17. |
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| 18. |
- Castellarin, A., et al.
(författare)
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Floodplain management strategies for flood attenuation in the river Po
- 2011
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Ingår i: Rivers Research and Applications. - : Wiley. - 1535-1459 .- 1535-1467. ; 27:8, s. 1037-1047
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Tidskriftsartikel (refereegranskat)abstract
- This paper analyses the effects of different floodplain management policies on flood hazard using a 350 km reach of the river Po (Italy) as a case study. The river Po is the longest Italian river, and the largest in terms of streamflow. The middle-lower Po flows East some 350 km in the Pianura Padana (Po Valley), a very important agricultural region and industrial heart of Northern Italy. This portion of the river consists of a main channel (200–500 m wide) and a floodplain (overall width from 200 m to 5 km) confined by two continuous artificial embankments. Floodplains are densely cultivated, and a significant portion of these areas is protected against frequent flooding by a system of minor dykes, which impacts significantly the hydraulic behaviour of the middle-lower Po during major flood events. This study aims at investigating the effects of the adoption of different floodplain management strategies (e.g. raising, lowering or removing the minor dyke system) on the hydrodynamics of the middle-lower Po and, in particular, on flood-risk mitigation. This is a crucial task for institutions and public bodies in charge of formulating robust flood risk management strategies for the river Po. Furthermore, the results of this study are of interest for other European water-related public bodies managing large river basins, in the light of the recent European Directive 2007/60/EC on the assessment and management of flood risks. The analysis is performed by means of a quasi-2D hydraulic model, which has been developed on the basis of a laser-scanning DTM and a large amount of calibration data recorded during the significant flood event of October 2000.
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| 19. |
- CASTELLARIN, A, et al.
(författare)
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Optimal Cross-Sectional Spacing in Preissmann Scheme 1D Hydrodynamic Models
- 2009
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Ingår i: Journal of Hydraulic Engineering. - 0733-9429 .- 1943-7900. ; 135:2, s. 96-105
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Tidskriftsartikel (refereegranskat)abstract
- Choosing a suitable set of cross sections for the representation of the natural geometry of a river is important for the efficiency of one-dimensional (1D) hydraulic models, but only few guidelines are available for the selection of the most suitable distance between cross sections, depending on the hydraulic problem at hand. This issue is investigated by examining models of a ∼55km reach of the River Po, Italy, and a ∼16km reach of the River Severn, United Kingdom, for both of which high quality laser scanning altimetry are available. The high-resolution digital terrain models of the two river reaches enabled the construction of a series of hypothetical topographical ground surveys with different spacing between cross sections, which could be used as input to a standard 1D model (UNET). Both historical and synthetic flood events for the two river reaches were simulated, and the results were then analyzed to quantify the accuracy associated with each resolution and to assess how survey resolution impacts the performance of standard 1D models. The study results agree with the available suggestions in the literature and provide useful guidelines for 1D hydrodynamic modeling.
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| 20. |
- Ceola, Serena, et al.
(författare)
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Adaptation of water resources systems to changing society and environment : a statement by the International Association of Hydrological Sciences
- 2016
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Ingår i: Hydrological Sciences Journal. - : Taylor & Francis Group. - 0262-6667 .- 2150-3435. ; 61:16, s. 2803-2817
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Forskningsöversikt (refereegranskat)abstract
- We explore how to address the challenges of adaptation of water resources systems under changing conditions by supporting flexible, resilient and low-regret solutions, coupled with on-going monitoring and evaluation. This will require improved understanding of the linkages between biophysical and social aspects in order to better anticipate the possible future co-evolution of water systems and society. We also present a call to enhance the dialogue and foster the actions of governments, the international scientific community, research funding agencies and additional stakeholders in order to develop effective solutions to support water resources systems adaptation. Finally, we call the scientific community to a renewed and unified effort to deliver an innovative message to stakeholders. Water science is essential to resolve the water crisis, but the effectiveness of solutions depends, inter alia, on the capability of scientists to deliver a new, coherent and technical vision for the future development of water systems.
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| 21. |
- Ceola, S., et al.
(författare)
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Drought and Human Mobility in Africa
- 2023
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Ingår i: Earth's Future. - : American Geophysical Union (AGU). - 2328-4277. ; 11:12
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Tidskriftsartikel (refereegranskat)abstract
- Human mobility from droughts is multifaceted and depends on environmental, political, social, demographic and economic factors. Although droughts cannot be considered as the single trigger, they significantly influence people's decision to move. Yet, the ways in which droughts influence patterns of human settlements have remained poorly understood. Here we explore the relationships between drought occurrences and changes in the spatial distribution of human settlements across 50 African countries for the period 1992-2013. For each country, we extract annual drought occurrences from two indicators, the international disaster database EM-DAT and the standardized precipitation evapotranspiration index (SPEI-12) records, and we evaluate human settlement patterns by considering urban population data and human distance to rivers, as derived from nighttime lights. We then compute human displacements as variations in human distribution between adjacent years, which are then associated with drought (or non-drought) years. Our results show that drought occurrences across Africa are often associated with (other things being equal) human mobility toward rivers or cities. In particular, we found that human settlements tend to get closer to water bodies or urban areas during drought conditions, as compared to non-drought periods, in 70%-81% of African countries. We interpret this tendency as a physical manifestation of drought adaptation, and discuss how this may result into increasing flood risk or overcrowding urban areas. As such, our results shed light on the interplay between human mobility and climate change, bolstering the analysis on the spatiotemporal dynamics of drought risks in a warming world. Prolonged water shortages induced by droughts can have severe consequences on both the environment and society. For instance, the mobility of people can be influenced by drought events. In order to test this assumption, we relate the movement of people to drought occurrences, without considering any additional factor. We focus on Africa, since it is one of the most drought-prone continents and the movement of people is more prominent compared to other areas. We find that people tend to move closer to rivers and to urban centers during droughts, as compared to non-drought periods. This pattern is found for the majority of African countries, which suggests a large-scale signal. The increased movement of people toward rivers during droughts might generate larger human losses if flood events take place in the future. A new methodology integrating satellite data is developed for evaluating drought-induced human displacements in AfricaWe found that 70%-81% of African countries exhibit larger displacements during droughts, as compared to non-drought periodsHuman displacement toward rivers and urban centers is triggered, other things being equal, by drought occurrences
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| 22. |
- Ciullo, Alessio, et al.
(författare)
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Socio-hydrological modelling of flood-risk dynamics : comparing the resilience of green and technological systems
- 2017
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Ingår i: Hydrological Sciences Journal. - : Informa UK Limited. - 0262-6667 .- 2150-3435. ; 62:6, s. 880-891
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Tidskriftsartikel (refereegranskat)abstract
- This work aims to provide a dynamic assessment of flood risk and community resilience by explicitly accounting for variable human behaviour, e.g. risk-taking and awareness-raising attitudes. We consider two different types of socio-hydrological systems: green systems, whereby societies deal with risk only via non-structural measures, and technological systems, whereby risk is dealt with also by structural measures, such as levees. A stylized model of human-flood interactions is first compared to real-world data collected at two test sites (People's Republic of Bangladesh and the city of Rome, Italy) and then used to explore plausible trajectories of flood risk. The results show that flood risk in technological systems tends to be significantly lower than in green systems. However, technological systems may undergo catastrophic events, which lead to much higher losses. Furthermore, green systems prove to be more resilient than technological ones, which makes them more capable of withstanding environmental and social changes.
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| 23. |
- Collenteur, R. A., et al.
(författare)
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The failed-levee effect : Do societies learn from flood disasters?
- 2015
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Ingår i: Natural Hazards. - : Springer Science and Business Media LLC. - 0921-030X .- 1573-0840. ; 76:1, s. 373-388
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Tidskriftsartikel (refereegranskat)abstract
- Human societies have learnt to cope with flood risks in several ways, the most prominent ways being engineering solutions and adaptive measures. However, from a more sustainable point of view, it can be argued that societies should avoid or at least minimize urban developments in floodplain areas. While many scientists have studied the impact of human activities on flood risk, only a few studies have investigated the opposite relationships, i.e. the impacts of past flood events on floodplain development. In this study, we make an initial attempt to understand the impact of the occurrence of flood disasters on the spatial distribution of population dynamics in floodplain areas. Two different methodologies are used to uncover this relationship, a large-scale study for the USA and a case-study analysis of the 1993 Mississippi flood. The large-scale analysis is performed at county level scale for the whole of the USA and indicates a positive relationship between property damage due to flood events and population growth. The case-study analysis examines a reach of the Mississippi river and the territory, which was affected by flooding in 1993. Contrary to the large-scale analysis, no significant relationship is found in this detailed study. However, a trend of dampened population growth right after the flood followed by an accelerated growth a decade later could be identified in the raw data and linked to explanations found in the literature.
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| 24. |
- Dang, Qian, et al.
(författare)
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A theoretical model of water and trade
- 2016
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Ingår i: Advances in Water Resources. - : Elsevier BV. - 0309-1708 .- 1872-9657. ; 89, s. 32-41
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Tidskriftsartikel (refereegranskat)abstract
- Water is an essential input for agricultural production. Agriculture, in turn, is globalized through the trade of agricultural commodities. In this paper, we develop a theoretical model that emphasizes four tradeoffs involving water-use decision-making that are important yet not always considered in a consistent framework. One tradeoff focuses on competition for water among different economic sectors. A second tradeoff examines the possibility that certain types of agricultural investments can offset water use. A third tradeoff explores the possibility that the rest of the world can be a source of supply or demand for a country's water-using commodities. The fourth tradeoff concerns how variability in water supplies influences farmer decision-making. We show conditions under which trade liberalization affect water use. Two policy scenarios to reduce water use are evaluated. First, we derive a target tax that reduces water use without offsetting the gains from trade liberalization, although important tradeoffs exist between economic performance and resource use. Second, we show how subsidization of water-saving technologies can allow producers to use less water without reducing agricultural production, making such subsidization an indirect means of influencing water use decision-making. Finally, we outline conditions under which riskiness of water availability affects water use. These theoretical model results generate hypotheses that can be tested empirically in future work.
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| 25. |
- De Luca, Paolo, et al.
(författare)
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Concurrent wet and dry hydrological extremes at the global scale
- 2020
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Ingår i: Earth System Dynamics. - : Copernicus GmbH. - 2190-4979 .- 2190-4987. ; 11:1, s. 251-266
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Tidskriftsartikel (refereegranskat)abstract
- Multi-hazard events can be associated with larger socio-economic impacts than single-hazard events. Understanding the spatio-temporal interactions that characterize the former is therefore of relevance to disaster risk reduction measures. Here, we consider two high-impact hazards, namely wet and dry hydrological extremes, and quantify their global co-occurrence. We define these using the monthly self-calibrated Palmer Drought Severity Index based on the Penman-Monteith model (sc_PDSI_pm), covering the period 1950-2014, at 2.5 degrees horizontal resolution. We find that the land areas affected by extreme wet, dry, and wet-dry events (i.e. geographically remote yet temporally co-occurring wet or dry extremes) are all increasing with time, the trends of which in dry and wet-dry episodes are significant (p value << 0.01). The most geographically widespread wet-dry event was associated with the strong La Nina in 2010. This caused wet-dry anomalies across a land area of 21 million km(2) with documented high-impact flooding and drought episodes spanning diverse regions. To further elucidate the interplay of wet and dry extremes at a grid cell scale, we introduce two new metrics: the wet-dry (WD) ratio and the extreme transition (ET) time intervals. The WD ratio measures the relative occurrence of wet or dry extremes, whereas ET quantifies the average separation time of hydrological extremes with opposite signs. The WD ratio shows that the incidence of wet extremes dominates over dry extremes in the USA, northern and southern South America, northern Europe, north Africa, western China, and most of Australia. Conversely, dry extremes are more prominent in most of the remaining regions. The median ET for wet to dry is similar to 27 months, while the dry-to-wet median ET is 21 months. We also evaluate correlations between wet-dry hydrological extremes and leading modes of climate variability, namely the El Nina-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and Atlantic Multi-decadal Oscillation (AMO). We find that ENSO and PDO have a similar influence globally, with the former significantly impacting (p value < 0.05) a larger area (18.1 % of total sc_PDSI_pm area) compared to the latter (12.0 %), whereas the AMO shows an almost inverse pattern and significantly impacts the largest area overall (18.9 %). ENSO and PDO show the most significant correlations over northern South America, the central and western USA, the Middle East, eastern Russia, and eastern Australia. On the other hand, the AMO shows significant associations over Mexico, Brazil, central Africa, the Arabian Peninsula, China, and eastern Russia. Our analysis brings new insights on hydrological multi-hazards that are of relevance to governments and organizations with globally distributed interests. Specifically, the multi-hazard maps may be used to evaluate worst-case disaster scenarios considering the potential co-occurrence of wet and dry hydrological extremes.
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