Special Issue "River, Urban, and Coastal Flood Risk"

A special issue of Geosciences (ISSN 2076-3263). This special issue belongs to the section "Natural Hazards".

Deadline for manuscript submissions: closed (1 November 2018)

Special Issue Editor

Guest Editor
Dr. Jeremy D. Bricker

Delft University of Technology, Dept. of Hydraulic Engineering, The Netherlands
Website | E-Mail
Interests: storm surge; tsunami; flood; hydraulic structure; bridge; hydropower; critical infrastructure

Special Issue Information

Dear Colleagues,

Coastal, fluvial, and pluvial floods cause casualties and damage throughout the world. Climate change is increasing flood hazard in many regions, while human development is exacerbating the consequences of flooding. Engineers, scientists, planners, and policy makers work to reduce flood risk via physical, social, and regulatory measures. Examples of these are engineered (hard) and natural (soft) defenses such as levees and wetlands, warning systems combined with education and evacuation protocols, and land use control. The effectiveness of an implemented countermeasure relies on both the robustness of the countermeasure chosen and the interdisciplinary interplay among the type of hazard, the appropriateness of the countermeasure itself, and the interaction of the countermeasure with the humans and property that it is meant to protect.

The purpose of this special issue is to investigate coastal, fluvial, and pluvial flood risk from disciplinary perspectives, as well as from viewpoints spanning these disciplines, including but not limited to:

  • Hazard assessment
  • Consequences (damage and loss) assessment
  • Physical (engineered and natural), social, and regulatory countermeasures

Please contribute your own research to this special issue.

Dr. Jeremy D. Bricker
Guest Editor

Manuscript Submission Information

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Keywords

  • storm surge
  • tsunami
  • flood
  • critical infrastructure
  • hard vs. soft countermeasures
  • hydraulic structures
  • warning
  • evacuation

Published Papers (14 papers)

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Research

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Open AccessArticle Sentinel-1 for Monitoring Land Subsidence of Coastal Cities in Africa Using PSInSAR: A Methodology Based on the Integration of SNAP and StaMPS
Geosciences 2019, 9(3), 124; https://doi.org/10.3390/geosciences9030124
Received: 13 January 2019 / Revised: 4 March 2019 / Accepted: 5 March 2019 / Published: 12 March 2019
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Abstract
The sub-Saharan African coast is experiencing fast-growing urbanization, particularly around major cities. This threatens the equilibrium of the socio-ecosystems where they are located and on which they depend: underground water resources are exploited with a disregard for sustainability; land is reclaimed from wetlands [...] Read more.
The sub-Saharan African coast is experiencing fast-growing urbanization, particularly around major cities. This threatens the equilibrium of the socio-ecosystems where they are located and on which they depend: underground water resources are exploited with a disregard for sustainability; land is reclaimed from wetlands or lagoons; built-up areas, both formal and informal, grow without adequate urban planning. Together, all these forces can result in land surface deformation, subsidence or even uplift, which can increase risk within these already fragile socio-ecosystems. In particular, in the case of land subsidence, the risk of urban flooding can increase significantly, also considering the contribution of sea level rise driven by climate change. Monitoring such fast-changing environments is crucial to be able to identify key risks and plan adaptation responses to mitigate current and future flood risks. Persistent scatterer interferometry (PSI) with synthetic aperture radar (SAR) is a powerful tool to monitor land deformation with high precision using relatively low-cost technology, also thanks to the open access data of Sentinel-1, which provides global observations every 6 days at 20-m ground resolution. In this paper, we demonstrate how it is possible to monitor land subsidence in urban coastal areas by means of permanent scatterer interferometry and Sentinel-1, exploiting an automatic procedure based on an integration of the Sentinel Application Platform (SNAP) and the Stanford Method for Persistent Scatterers (StaMPS). We present the results of PSI analysis over the cities of Banjul (the Gambia) and Lagos (Nigeria) showing a comparison of results obtained with TerraSAR-X, Constellation of Small Satellites for the Mediterranean Basin Observation (COSMO-SkyMed) and Environmental Satellite advanced synthetic aperture radar (Envisat-ASAR) data. The methodology allows us to highlight areas of high land deformation, information that is useful for urban development, disaster risk management and climate adaptation planning. Full article
(This article belongs to the Special Issue River, Urban, and Coastal Flood Risk)
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Open AccessArticle Modelling Coastal Flood Propagation under Sea Level Rise: A Case Study in Maria, Eastern Canada
Geosciences 2019, 9(2), 76; https://doi.org/10.3390/geosciences9020076
Received: 5 January 2019 / Revised: 26 January 2019 / Accepted: 29 January 2019 / Published: 2 February 2019
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Abstract
Coastal management often relies on large-scale flood mapping to produce sea level rise assessments where the storm-related surge is considered as the most important hazard. Nearshore dynamics and overland flow are also key parameters in coastal flood mapping, but increase the model complexity. [...] Read more.
Coastal management often relies on large-scale flood mapping to produce sea level rise assessments where the storm-related surge is considered as the most important hazard. Nearshore dynamics and overland flow are also key parameters in coastal flood mapping, but increase the model complexity. Avoiding flood propagation processes using a static flood mapping is less computer-intensive, but generally leads to overestimation of the flood zone, especially in defended urban backshore. For low-lying communities, sea level rise poses a certain threat, but its consequences are not only due to a static water level. In this paper, the numerical process-based model XBeach is used in 2D hydrodynamic mode (surfbeat) to reproduce an observed historical flood in Maria (eastern Canada). The main goal is to assess the impacts of a future storm of the same magnitude in the horizon 2100 according to an increase in sea level rise. The model is first validated from in situ observations of waves and water levels observed on the lower foreshore. Based on field observations of a flood extent in 2010, the simulated flooded area was also validated given a good fit (59%) with the actual observed flood. Results indicate that the 2010 storm-induced surge generated overwash processes on multiple areas and net landward sediment transport and accumulation (washover lobes). The flood was caused by relatively small nearshore waves (Hs < 1 m), but despite small water depth (>1.2 m), high flow velocities occurred in the main street (U > 2 m/s) prior to draining in the salt marsh. The impact of sea level rise on the low-lying coastal community of Maria could induce a larger flood area in 2100, deeper floodwater, and higher flow velocities, resulting in higher hazard for the population. Full article
(This article belongs to the Special Issue River, Urban, and Coastal Flood Risk)
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Open AccessArticle Comparative Analysis of Tsunami Recovery Strategies in Small Communities in Japan and Chile
Geosciences 2019, 9(1), 26; https://doi.org/10.3390/geosciences9010026
Received: 26 November 2018 / Revised: 24 December 2018 / Accepted: 31 December 2018 / Published: 7 January 2019
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Abstract
The Sendai Framework for Disaster Risk Reduction emphasizes the need to rebuild better after a disaster to ensure that the at-risk communities can withstand a similar or stronger shock in the future. In the present work, the authors analyzed the reconstruction paths through [...] Read more.
The Sendai Framework for Disaster Risk Reduction emphasizes the need to rebuild better after a disaster to ensure that the at-risk communities can withstand a similar or stronger shock in the future. In the present work, the authors analyzed the reconstruction paths through a comparative analysis of the perspective of a community in Japan and another in Chile, and their respective local governments. While both countries are at risk to tsunamis, they follow different reconstruction philosophies. Data was gathered through key informant interviews of community members and local government officials, by adapting and modifying the Building Resilience to Adapt to Climate Extremes and Disasters (BRACED) 3As framework to a tsunami scenario. The 3As represent anticipatory, adaptive, and absorptive capacities as well as transformative capacities and respondents were asked to rate this according to their perspectives. It was found that while both communities perceive that much is to be done in recovery, Kirikiri has a more holistic and similar perspective of the recovery with their government officials as compared to Dichato. This shows that community reconstruction and recovery from a disaster requires a holistic participation and understanding. Full article
(This article belongs to the Special Issue River, Urban, and Coastal Flood Risk)
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Open AccessArticle Unsteady Seepage Behavior of an Earthfill Dam During Drought-Flood Cycles
Geosciences 2019, 9(1), 17; https://doi.org/10.3390/geosciences9010017
Received: 6 December 2018 / Revised: 21 December 2018 / Accepted: 24 December 2018 / Published: 28 December 2018
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Abstract
Climate change with extreme hydrological conditions, such as drought and flood, bring new challenges to seepage behavior and the stability of earthfill dams. Taking a drought-stricken earthfill dam of China as an example, the influence of drought-flood cycles on dam seepage behavior is [...] Read more.
Climate change with extreme hydrological conditions, such as drought and flood, bring new challenges to seepage behavior and the stability of earthfill dams. Taking a drought-stricken earthfill dam of China as an example, the influence of drought-flood cycles on dam seepage behavior is analyzed. This paper includes a clay sample laboratory experiment and an unsteady finite element method seepage simulation of the mentioned dam. Results show that severe drought causes cracks on the surface of the clay soil sample. Long-term drought causes deeper cracks and induces a sharp increase of suction pressure, indicating that the cracks would become channels for rain infiltration into the dam during subsequent rainfall, increasing the potential for internal erosion and decreasing dam stability. Measures to prevent infiltration on the dam slope surface are investigated, for the prevention of deep crack formation during long lasting droughts. Unsteady seepage indicators including instantaneous phreatic lines, equipotential lines and pore pressure gradient in the dam, are calculated and analyzed under two assumed conditions with different reservoir water level fluctuations. Results show that when the water level changes rapidly, the phreatic line is curved and constantly changing. As water level rises, equipotential lines shift upstream, and the pore pressure gradient in the dam’s main body is larger than that of steady seepage. Furthermore, the faster the water level rises, the larger the pore pressure gradient is. This may cause internal erosion. Furthermore, the case of a cracked upstream slope is modelled via an equivalent permeability coefficient, which shows that the pore pressure gradient in the zone beneath the cracks increases by 5.9% at the maximum water level; this could exacerbate internal erosion. In addition, results are in agreement with prior literature that rapid drawdown of the reservoir water level is detrimental to the stability of the upstream slope based on embankment slope stability as calculated by the Simplified Bishop Method. It is concluded that fluctuations of reservoir water level should be strictly controlled during drought-flood cycles; both the drawdown rate and the fill rate must be regulated to avoid the internal erosion of earthfill dams. Full article
(This article belongs to the Special Issue River, Urban, and Coastal Flood Risk)
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Open AccessArticle Comparison of Implicit and Explicit Vegetation Representations in SWAN Hindcasting Wave Dissipation by Coastal Wetlands in Chesapeake Bay
Received: 28 November 2018 / Revised: 14 December 2018 / Accepted: 21 December 2018 / Published: 24 December 2018
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Abstract
Assessing the accuracy of nearshore numerical models—such as SWAN—is important to ensure their effectiveness in representing physical processes and predicting flood hazards. In particular, for application to coastal wetlands, it is important that the model accurately represents wave attenuation by vegetation. In SWAN, [...] Read more.
Assessing the accuracy of nearshore numerical models—such as SWAN—is important to ensure their effectiveness in representing physical processes and predicting flood hazards. In particular, for application to coastal wetlands, it is important that the model accurately represents wave attenuation by vegetation. In SWAN, vegetation might be implemented either implicitly, using an enhanced bottom friction; or explicitly represented as drag on an immersed body. While previous studies suggest that the implicit representation underestimates dissipation, field data has only recently been used to assess fully submerged vegetation. Therefore, the present study investigates the performance of both the implicit and explicit representations of vegetation in SWAN in simulating wave attenuation over a natural emergent marsh. The wave and flow modules within Delft3D are used to create an open-ocean model to simulate offshore wave conditions. The domain is then decomposed to simulate nearshore processes and provide the boundary conditions necessary to run a standalone SWAN model. Here, the implicit and explicit representations of vegetation are finally assessed. Results show that treating vegetation simply as enhanced bottom roughness (implicitly) under-represents the complexity of wave-vegetation interaction and, consequently, underestimates wave energy dissipation (error > 30%). The explicit vegetation representation, however, shows good agreement with field data (error < 20%). Full article
(This article belongs to the Special Issue River, Urban, and Coastal Flood Risk)
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Open AccessArticle Emergency Flood Control: Practice-Oriented Test Series for the Use of Sandbag Replacement Systems
Geosciences 2018, 8(12), 482; https://doi.org/10.3390/geosciences8120482
Received: 30 October 2018 / Revised: 10 December 2018 / Accepted: 11 December 2018 / Published: 13 December 2018
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Abstract
In operational flood defense, it is common practice to use sandbag systems. However, their installation is time-consuming as well as material- and labor-intensive. Sandbag replacement systems (SBRSs) can be installed in significantly shorter time and with less effort. However, owing to the lack [...] Read more.
In operational flood defense, it is common practice to use sandbag systems. However, their installation is time-consuming as well as material- and labor-intensive. Sandbag replacement systems (SBRSs) can be installed in significantly shorter time and with less effort. However, owing to the lack of confidence in their functionality, they are only used to a limited extent. Testing and certifying such innovative systems according to defined criteria is supportive in promoting their use in flood defense. In order to test SBRSs and as a first step toward systematic tests, the Institute for Hydraulic and Coastal Engineering of the Bremen University of Applied Sciences, Germany (IWA) has set up a test facility in which defined test series can be carried out with different SBRSs on an underlying surface of turf. The focus of the test series is on installation time, possible water head, system stability, and seepage rates when in use. A conventional sandbag dam was used as reference in order to compare the test results with the different SBRSs. Test series show that damming with SBRSs has a clear advantage over the use of sandbags in terms of the time it takes to put them in place and comparable values of seepage rates and water heads. In order to professionally promote the spread of SBRSs in operational flood protection, it is recommended to introduce the certification of SBRSs, since they are technical systems whose functional capability must be proven before their use in an emergency. Together with existing international certification schemes, the test series that were carried out deliver a basis for developing a specific testing scheme for SBRSs. Full article
(This article belongs to the Special Issue River, Urban, and Coastal Flood Risk)
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Open AccessArticle The Severe 2013–14 Winter Storms in the Historical Evolution of Cantabrian (Northern Spain) Beach-Dune Systems
Geosciences 2018, 8(12), 459; https://doi.org/10.3390/geosciences8120459
Received: 16 November 2018 / Revised: 30 November 2018 / Accepted: 1 December 2018 / Published: 5 December 2018
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Abstract
The 2013–14 winter storms were the most energetic storms in the European Atlantic on record since at least 1948. They caused intense erosive processes along the coast, similar to those described previously in places such as the United Kingdom and France. In this [...] Read more.
The 2013–14 winter storms were the most energetic storms in the European Atlantic on record since at least 1948. They caused intense erosive processes along the coast, similar to those described previously in places such as the United Kingdom and France. In this study, an analysis is conducted of the historical evolution (1956–2017) of four dune systems in the region of Cantabria (northern Spain) and their response to such storms. The analysis uses aerial images (from 1956, 2002, 2010, 2014, and 2017) implemented in ArcGIS, and the Digital Shoreline Analysis System (DSAS) model for the estimation of a series of statistical parameters relative to the historical behavior of the shoreline. The DSAS model allows a geometric structure to be calculated that is flexible and can be adapted to the morphological conditions of the coast. The results obtained from the model for the entire historical period and the pre-storm analysis show clear variability in the evolution of the dune systems, while the post-storm analysis yields homogeneous results that indicate significant erosion, with no signs of recovery. The limited time elapsed since the 2013–14 winter storm clustering and the high interannual energy variability of the subsequent winters seem to be behind the absence of evidence of dune system recovery and even the increase in the erosion processes observed in some cases. Full article
(This article belongs to the Special Issue River, Urban, and Coastal Flood Risk)
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Open AccessArticle Survey Tool for Rapid Assessment of Socio-Economic Vulnerability of Fishing Communities in Vietnam to Climate Change
Geosciences 2018, 8(12), 452; https://doi.org/10.3390/geosciences8120452
Received: 17 October 2018 / Revised: 10 November 2018 / Accepted: 29 November 2018 / Published: 3 December 2018
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Abstract
Climate change will likely affect the effectiveness of future management of coastal ecosystems, impacting communities that reside within the coastal area. In order to formulate appropriate adaptation counter-measures it is important to understand the actual vulnerability of the communities that depend on these [...] Read more.
Climate change will likely affect the effectiveness of future management of coastal ecosystems, impacting communities that reside within the coastal area. In order to formulate appropriate adaptation counter-measures it is important to understand the actual vulnerability of the communities that depend on these ecosystems. The present research proposes a tool for assessing the vulnerability of coastal communities to climate change by combining survey results with secondary and observed data available from national and local governments. The study focused on fisheries, given that they constitute the source of livelihood for many communities in developing countries such as Vietnam. The results showed that two coastal wards in Binh Thuan province, Vietnam, are highly vulnerable to the impacts of climate change, mainly because of their dependence on fisheries and the topography of the area. The seasonality of their source of livelihood affects the adaptive capacity of residents, making it less likely that they will be able to successfully adapt to changes in fishery resources that could be brought about by climate change. The results also showed that the communities are particularly vulnerable to sea level rise, given that they are both located in the immediate vicinity of the sea and are particularly low in elevation. Full article
(This article belongs to the Special Issue River, Urban, and Coastal Flood Risk)
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Open AccessArticle Contributions to Coastal Flooding Events in Southeast of Vietnam and their link with Global Mean Sea Level Rise
Geosciences 2018, 8(12), 437; https://doi.org/10.3390/geosciences8120437
Received: 8 August 2018 / Revised: 21 November 2018 / Accepted: 22 November 2018 / Published: 26 November 2018
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Abstract
This work analyzes the components of the total water level (TWL) that cause flooding in a tropical coastal area (Nha Trang beach, Southeast of Vietnam), and examines their link with global mean sea level rise (GMSLR). Interactions between the wave induced run-up (R) [...] Read more.
This work analyzes the components of the total water level (TWL) that cause flooding in a tropical coastal area (Nha Trang beach, Southeast of Vietnam), and examines their link with global mean sea level rise (GMSLR). Interactions between the wave induced run-up (R) and astronomical tide (AT) were responsible for 43% of the 35 flooding events identified between 1993 and 2015. Most of these events (97%) took place during the winter monsoon season, when long-lasting extreme R and positive non-tidal residual (NTR) are likely to occur. Removal of the GMSLR trend from the NTR was found to affect the flood occurrence of 17% of these events, while the trend in wave height did not have any detectable impact. Our research highlights the direct connection between global climate changes and coastal flooding events. Full article
(This article belongs to the Special Issue River, Urban, and Coastal Flood Risk)
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Open AccessArticle Field Survey of 2018 Typhoon Jebi in Japan: Lessons for Disaster Risk Management
Geosciences 2018, 8(11), 412; https://doi.org/10.3390/geosciences8110412
Received: 10 October 2018 / Revised: 6 November 2018 / Accepted: 7 November 2018 / Published: 9 November 2018
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Abstract
Typhoon Jebi struck Japan on the 4 September 2018, damaging and inundating many coastal areas along Osaka Bay due to the high winds, a storm surge, and wind driven waves. In order to understand the various damage mechanisms, the authors conducted a field [...] Read more.
Typhoon Jebi struck Japan on the 4 September 2018, damaging and inundating many coastal areas along Osaka Bay due to the high winds, a storm surge, and wind driven waves. In order to understand the various damage mechanisms, the authors conducted a field survey two days after the typhoon made landfall, measuring inundation heights and depths at several locations in Hyogo Prefecture. The survey results showed that 0.18–1.27 m inundation depths were caused by Typhoon Jebi. As parts of the survey, local residents were interviewed about the flooding, and a questionnaire survey regarding awareness of typhoons and storm surges, and their response to the typhoon was distributed. The authors also mapped the location of some of the containers that were displaced by the storm surge, aiming to provide information to validate future simulation models of container displacement. Finally, some interesting characteristics of the storm surge are summarized, such as possible overtopping at what had initially been thought to be a low risk area (Suzukaze town), and lessons learnt in terms of disaster risk management are discussed. Full article
(This article belongs to the Special Issue River, Urban, and Coastal Flood Risk)
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Open AccessArticle Hydrodynamic and Debris-Damming Failure of Bridge Decks and Piers in Steady Flow
Geosciences 2018, 8(11), 409; https://doi.org/10.3390/geosciences8110409
Received: 9 October 2018 / Revised: 31 October 2018 / Accepted: 5 November 2018 / Published: 9 November 2018
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Abstract
In countries with steep rivers, such as Japan and the United States, bridges fail on an annual basis. Bridges on spread footings are especially susceptible to failure by hydrodynamic loading, often exacerbated by debris damming. Here, such failures are investigated via small scale [...] Read more.
In countries with steep rivers, such as Japan and the United States, bridges fail on an annual basis. Bridges on spread footings are especially susceptible to failure by hydrodynamic loading, often exacerbated by debris damming. Here, such failures are investigated via small scale model laboratory experiments and full scale numerical simulations. In the laboratory, lift and drag forces and overturning moment on bridge decks, piers, and deck-pier systems, are measured and compared with threshold of failure criteria used in design guidelines. Effects of debris on lift, drag, and moment, as well as three-dimensional effects, are quantified. Via numerical simulations, flow patterns and free surface behaviour responsible for these forces are investigated, and described in a framework as a function of the water depth, flow speed, deck clearance, and girder height. Results show that current guidelines are non-conservative in some cases. Importantly, failure of both decks and piers can be prevented by strengthening pier-deck connections, or by streamlining decks. Full article
(This article belongs to the Special Issue River, Urban, and Coastal Flood Risk)
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Open AccessArticle Stability of Individuals during Urban Inundations: What Should We Learn from Field Observations?
Geosciences 2018, 8(9), 341; https://doi.org/10.3390/geosciences8090341
Received: 25 July 2018 / Revised: 5 September 2018 / Accepted: 7 September 2018 / Published: 10 September 2018
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Abstract
The flooding of urbanized areas constitutes a major hazard to populations and infrastructure. Flood flows during urban inundations have been studied only recently and the real-life impact of fluid flows on individuals is not well understood. The stability of individuals in floodwaters is [...] Read more.
The flooding of urbanized areas constitutes a major hazard to populations and infrastructure. Flood flows during urban inundations have been studied only recently and the real-life impact of fluid flows on individuals is not well understood. The stability of individuals in floodwaters is re-assessed based upon the re-analysis of detailed field measurements during a major flood event. The results emphasized that hydrodynamic instabilities, linked to local topographic effects and debris, constitute major real-world hazards. A comparison between a number of flow conditions deemed unsafe for individuals, along with guidelines, suggests that many recommendations are over-optimistic and unsafe in real floodwaters and natural disasters. A series of more conservative guidelines is proposed, particularity relevant to flood events. Full article
(This article belongs to the Special Issue River, Urban, and Coastal Flood Risk)
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Review

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Open AccessReview Coastal Flood Modeling Challenges in Defended Urban Backshores
Geosciences 2018, 8(12), 450; https://doi.org/10.3390/geosciences8120450
Received: 1 November 2018 / Revised: 25 November 2018 / Accepted: 26 November 2018 / Published: 1 December 2018
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Abstract
Coastal flooding is a significant and increasing hazard. There are multiple drivers including rising coastal water levels, more intense hydrologic inputs, shoaling groundwater and urbanization. Accurate coastal flood event prediction poses numerous challenges: representing boundary conditions, depicting terrain and hydraulic infrastructure, integrating spatially [...] Read more.
Coastal flooding is a significant and increasing hazard. There are multiple drivers including rising coastal water levels, more intense hydrologic inputs, shoaling groundwater and urbanization. Accurate coastal flood event prediction poses numerous challenges: representing boundary conditions, depicting terrain and hydraulic infrastructure, integrating spatially and temporally variable overtopping flows, routing overland flows and incorporating hydrologic signals. Tremendous advances in geospatial data quality, numerical modeling and overtopping estimation have significantly improved flood prediction; however, risk assessments do not typically consider the co-occurrence of multiple flooding pathways. Compound flooding refers to the combined effects of marine and hydrologic processes. Alternatively, multiple flooding source–receptor pathways (e.g., groundwater–surface water, overtopping–overflow, surface–sewer flow) may simultaneously amplify coastal hazard and vulnerability. Currently, there is no integrated framework considering compound and multi-pathway flooding processes in a unified approach. State-of-the-art urban coastal flood modeling methods and research directions critical to developing an integrated framework for explicitly resolving multiple flooding pathways are presented. Full article
(This article belongs to the Special Issue River, Urban, and Coastal Flood Risk)
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Other

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Open AccessConcept Paper Risk-Based Early Warning System for Pluvial Flash Floods: Approaches and Foundations
Geosciences 2019, 9(3), 127; https://doi.org/10.3390/geosciences9030127
Received: 11 February 2019 / Revised: 7 March 2019 / Accepted: 8 March 2019 / Published: 14 March 2019
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Abstract
In times of increasing weather extremes and expanding vulnerable cities, a significant risk to civilian security is posed by heavy rainfall induced flash floods. In contrast to river floods, pluvial flash floods can occur anytime, anywhere and vary enormously due to both terrain [...] Read more.
In times of increasing weather extremes and expanding vulnerable cities, a significant risk to civilian security is posed by heavy rainfall induced flash floods. In contrast to river floods, pluvial flash floods can occur anytime, anywhere and vary enormously due to both terrain and climate factors. Current early warning systems (EWS) are based largely on measuring rainfall intensity or monitoring water levels, whereby the real danger due to urban torrential floods is just as insufficiently considered as the vulnerability of the physical infrastructure. For this reason, this article presents a concept for a risk-based EWS as one integral component of a multi-functional pluvial flood information system (MPFIS). Taking both the pluvial flood hazard as well as the damage potential into account, the EWS identifies the urban areas particularly affected by a forecasted heavy rainfall event and issues object-precise warnings in real-time. Further, the MPFIS performs a georeferenced documentation of occurred events as well as a systematic risk analysis, which at the same time forms the foundation of the proposed EWS. Based on a case study in the German city of Aachen and the event of 29 May 2018, the operation principle of the integrated information system is illustrated. Full article
(This article belongs to the Special Issue River, Urban, and Coastal Flood Risk)
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