Editorial

3 pages, 168 KiB

Open AccessEditorial

Editorial to the Special Issue: Impacts of Compound Hydrological Hazards or Extremes

by Lindsay Beevers, Christopher J. White and Maria Pregnolato

Geosciences 2020, 10(12), 496; https://doi.org/10.3390/geosciences10120496 - 09 Dec 2020

Cited by 2 | Viewed by 1818

Hydrological hazards, or ‘hydro-hazards’, are defined as “extreme events associated with the occurrence, movement and distribution of water, such as floods and droughts” (Visser-Quinn et al [...] Full article

(This article belongs to the Special Issue Impacts of Compound Hydrological Hazards or Extremes)

Research

Jump to: Editorial

22 pages, 8482 KiB

Open AccessArticle

Impacts of Triple Factors on Flash Flood Vulnerability in Egypt: Urban Growth, Extreme Climate, and Mismanagement

by Mohamed Saber, Karim I. Abdrabo, Omar M. Habiba, Sameh A. Kantosh and Tetsuya Sumi

Geosciences 2020, 10(1), 24; https://doi.org/10.3390/geosciences10010024 - 10 Jan 2020

Cited by 46 | Viewed by 8050

Abstract

Urban growth, extreme climate, and mismanagement are crucial controlling factors that affect flood vulnerability at wadi catchments. Therefore, this study attempts to understand the impacts of these three factors on the flash flood vulnerability in different climatic regions in Egypt. An integrated approach [...] Read more.

Urban growth, extreme climate, and mismanagement are crucial controlling factors that affect flood vulnerability at wadi catchments. Therefore, this study attempts to understand the impacts of these three factors on the flash flood vulnerability in different climatic regions in Egypt. An integrated approach is presented to evaluate the urban growth from 1984 to 2019 by using Google Images and SENTINEL-2 data, and to develop hazard maps by using a rainfall-runoff-inundation model (RRI). Annual rainfall trend analysis was performed to evaluate the temporal variability trend. The hazard maps that were created were classified into three categories (low, medium, and high) and integrated with the urban growth maps to evaluate the impacts on the flood-vulnerable areas. The results show a significant increase in urban growth resulting in an increase of prone areas for flood hazards over time. However, the degree of this hazard is mainly related to growth directions. Mismanagement affects urban growth directions in both planned and unplanned growth, whether by loss of control over unplanned growth or by deficiencies in approved plans. The rainfall analysis showed that there is no explicit relationship to increases or decreases in the flood vulnerable areas. An urban planning approach is recommended for risk reduction management based on a comprehensive study considering such factors. Full article

(This article belongs to the Special Issue Impacts of Compound Hydrological Hazards or Extremes)

► Show Figures

Figure 1

21 pages, 13527 KiB

Open AccessArticle

Analysis of Flood Storage Area Operations in Huai River Using 1D and 2D River Simulation Models Coupled with Global Optimization Algorithms

by Andreja Jonoski, Ioana Popescu, Sun Zhe, Yuhan Mu and Yiqing He

Geosciences 2019, 9(12), 509; https://doi.org/10.3390/geosciences9120509 - 06 Dec 2019

Cited by 11 | Viewed by 2952

Abstract

This article addresses the issue of flood management using four flood storage areas in the middle section of Huai River in China which protect the important downstream city of Bengbu. The same areas are also used by the local population as residential and [...] Read more.

This article addresses the issue of flood management using four flood storage areas in the middle section of Huai River in China which protect the important downstream city of Bengbu. The same areas are also used by the local population as residential and agricultural zones. An optimization problem is therefore posed, with two objectives of simultaneously minimizing the downstream flood risk in Bengbu city and the storage areas’ economic damages. The methodology involved development of river flood models using HEC-RAS, with varying complexity, such as 1-dimensional (1D) model with storage areas represented as lumped conceptual reservoirs, and 2-dimensional (2D) models with detailed representation of the terrain, land-use and hydrodynamics in the storage areas. Experiments of coupling these models with global optimization algorithms (NSGA-II, PESA-II and SPEA-II) were performed (using the HEC-RAS Controller), in which the two objective functions were minimized, while using stage differences between the river and the storage areas as decision variables for controlling the opening/closing of the gates at the lateral structures that link the river with the storage areas. The comparative analysis of the results indicate that more refined optimal operational strategies that spread the damages across all storage areas can be obtained only with the detailed flood simulation models, regardless of the optimization algorithm used. Full article

(This article belongs to the Special Issue Impacts of Compound Hydrological Hazards or Extremes)

► Show Figures

Figure 1

15 pages, 2051 KiB

Open AccessEditor’s ChoiceArticle

Quantification of Modelling Uncertainties in Bridge Scour Risk Assessment under Multiple Flood Events

by Alonso Pizarro and Enrico Tubaldi

Geosciences 2019, 9(10), 445; https://doi.org/10.3390/geosciences9100445 - 18 Oct 2019

Cited by 25 | Viewed by 3118

Abstract

Local scour is a dynamic process evolving during the lifetime of bridges as a result of the changes in hydrologic and hydraulic conditions. Current approaches for scour risk assessment are generally based on the evaluation of the equilibrium scour depth for a flood [...] Read more.

Local scour is a dynamic process evolving during the lifetime of bridges as a result of the changes in hydrologic and hydraulic conditions. Current approaches for scour risk assessment are generally based on the evaluation of the equilibrium scour depth for a flood event with a prefixed return period. The temporal evolution of the bridge-pier scour process is usually disregarded, by assuming that equilibrium conditions are always attained, regardless of the flood properties. However, recent studies have highlighted the importance of accounting for the contribution of multiple flood events and their exact hydrograph shape. This study aims at quantifying the epistemic uncertainty related to the modelling of the temporal evolution of scour under multiple consecutive flood events in clear-water conditions. A simple numerical case study is considered, using a Markovian framework to describe probabilistically the progression of scour. Well-known time-dependent scour models are used to estimate the temporal evolution of the scour-depth under each flood hydrograph, and the scour estimates are compared with those obtained using widely employed equilibrium scour formulas. Results show that the expected scour depth is influenced by the parameters used to describe the flood hydrograph and that the probability distribution of the scour depth is highly sensitive to the choice of the time-dependent scour model. The uncertainty in the scour estimation stemming from the formula adopted in this study for describing the temporal evolution of the scour depth can be higher than those related to the formula adopted for equilibrium scour. Full article

(This article belongs to the Special Issue Impacts of Compound Hydrological Hazards or Extremes)

► Show Figures

Figure 1

21 pages, 8693 KiB

Open AccessArticle

Assessing the Multiple Impacts of Extreme Hurricanes in Southern New England, USA

by David S. Ullman, Isaac Ginis, Wenrui Huang, Catherine Nowakowski, Xuanyu Chen and Peter Stempel

Geosciences 2019, 9(6), 265; https://doi.org/10.3390/geosciences9060265 - 19 Jun 2019

Cited by 14 | Viewed by 4583

Abstract

The southern New England coast of the United States is particularly vulnerable to land-falling hurricanes because of its east-west orientation. The impact of two major hurricanes on the city of Providence (Rhode Island, USA) during the middle decades of the 20th century spurred [...] Read more.

The southern New England coast of the United States is particularly vulnerable to land-falling hurricanes because of its east-west orientation. The impact of two major hurricanes on the city of Providence (Rhode Island, USA) during the middle decades of the 20th century spurred the construction of the Fox Point Hurricane Barrier (FPHB) to protect the city from storm surge flooding. Although the Rhode Island/Narragansett Bay area has not experienced a major hurricane for several decades, increased coastal development along with potentially increased hurricane activity associated with climate change motivates an assessment of the impacts of a major hurricane on the region. The ocean/estuary response to an extreme hurricane is simulated using a high-resolution implementation of the ADvanced CIRCulation (ADCIRC) model coupled to the Precipitation-Runoff Modeling System (PRMS). The storm surge response in ADCIRC is first verified with a simulation of a historical hurricane that made landfall in southern New England. The storm surge and the hydrological models are then forced with winds and rainfall from a hypothetical hurricane dubbed “Rhody”, which has many of the characteristics of historical storms that have impacted the region. Rhody makes landfall just west of Narragansett Bay, and after passing north of the Bay, executes a loop to the east and the south before making a second landfall. Results are presented for three versions of Rhody, varying in the maximum wind speed at landfall. The storm surge resulting from the strongest Rhody version (weak Saffir–Simpson category five) during the first landfall exceeds 7 m in height in Providence at the north end of the Bay. This exceeds the height of the FPHB, resulting in flooding in Providence. A simulation including river inflow computed from the runoff model indicates that if the Barrier remains closed and its pumps fail (for example, because of a power outage or equipment failure), severe flooding occurs north of the FPHB due to impoundment of the river inflow. These results show that northern Narragansett Bay could be particularly vulnerable to both storm surge and rainfall-driven flooding, especially if the FPHB suffers a power outage. They also demonstrate that, for wind-driven storm surge alone under present sea level conditions, the FPHB will protect Providence for hurricanes less intense than category five. Full article

(This article belongs to the Special Issue Impacts of Compound Hydrological Hazards or Extremes)

► Show Figures

Figure 1

17 pages, 8382 KiB

Open AccessArticle

Coastal Flood Assessment due to Sea Level Rise and Extreme Storm Events: A Case Study of the Atlantic Coast of Portugal’s Mainland

by Carlos Antunes, Carolina Rocha and Cristina Catita

Geosciences 2019, 9(5), 239; https://doi.org/10.3390/geosciences9050239 - 24 May 2019

Cited by 22 | Viewed by 7246

Abstract

Portugal’s mainland has hundreds of thousands of people living in the Atlantic coastal zone, with numerous high economic value activities and a high number of infrastructures that must be adapted and protected from natural coastal hazards, namely, extreme storms and sea level rise [...] Read more.

Portugal’s mainland has hundreds of thousands of people living in the Atlantic coastal zone, with numerous high economic value activities and a high number of infrastructures that must be adapted and protected from natural coastal hazards, namely, extreme storms and sea level rise (SLR). In the context of climate change adaptation strategies, a reliable and accurate assessment of the physical vulnerability to SLR is crucial. This study is a contribution to the implementation of flooding standards imposed by the European Directive 2007/60/EC, which requires each member state to assess the risk associated to SLR and floods caused by extreme events. Therefore, coastal hazard on the Atlantic Coast of Portugal’s mainland was evaluated for 2025, 2050, and 2100 over the whole extension due to SLR, with different sea level scenarios for different extreme event return periods. A coastal probabilistic flooding map was produced based on the developed probabilistic cartography methodology using geographic information system (GIS) technology. The Extreme Flood Hazard Index (EFHI) was determined on probabilistic flood bases using five probability intervals of 20% amplitude. For a given SLR scenario, the EFHI is expressed, on the probabilistic flooding maps for an extreme tidal maximum level, by five hazard classes ranging from 1 (Very Low) to 5 (Extreme). Full article

(This article belongs to the Special Issue Impacts of Compound Hydrological Hazards or Extremes)

► Show Figures

Figure 1

19 pages, 5334 KiB

Open AccessArticle

New Sensitivity Indices of a 2D Flood Inundation Model Using Gauss Quadrature Sampling

by Khalid Oubennaceur, Karem Chokmani, Miroslav Nastev, Yves Gauthier, Jimmy Poulin, Marion Tanguy, Sebastien Raymond and Rachid Lhissou

Geosciences 2019, 9(5), 220; https://doi.org/10.3390/geosciences9050220 - 14 May 2019

Cited by 5 | Viewed by 4086

Abstract

A new method for sensitivity analysis of water depths is presented based on a two-dimensional hydraulic model as a convenient and cost-effective alternative to Monte Carlo simulations. The method involves perturbation of the probability distribution of input variables. A relative sensitivity index is [...] Read more.

A new method for sensitivity analysis of water depths is presented based on a two-dimensional hydraulic model as a convenient and cost-effective alternative to Monte Carlo simulations. The method involves perturbation of the probability distribution of input variables. A relative sensitivity index is calculated for each variable, using the Gauss quadrature sampling, thus limiting the number of runs of the hydraulic model. The variable-related highest variation of the expected water depths is considered to be the most influential. The proposed method proved particularly efficient, requiring less information to describe model inputs and fewer model executions to calculate the sensitivity index. It was tested over a 45 km long reach of the Richelieu River, Canada. A 2D hydraulic model was used to solve the shallow water equations (SWE). Three input variables were considered: Flow rate, Manning’s coefficient, and topography of a shoal within the considered reach. Four flow scenarios were simulated with discharge rates of 759, 824, 936, and 1113

m^{3} / s

. The results show that the predicted water depths were most sensitive to the topography of the shoal, whereas the sensitivity indices of Manning’s coefficient and the flow rate were comparatively lower. These results are important for making better hydraulic models, taking into account the sensitivity analysis. Full article

(This article belongs to the Special Issue Impacts of Compound Hydrological Hazards or Extremes)

► Show Figures

Figure 1

12 pages, 1647 KiB

Open AccessCommunication

Brief Communication: Analysis of the Fatalities and Socio-Economic Impacts Caused by Hurricane Florence

by Srikanto Paul, Dawit Ghebreyesus and Hatim O. Sharif

Geosciences 2019, 9(2), 58; https://doi.org/10.3390/geosciences9020058 - 26 Jan 2019

Cited by 28 | Viewed by 9931

Abstract

Florence made landfall on the southeastern coast of North Carolina (NC) generating torrential rainfall and severe flooding that led to 53 fatalities in three states (NC, SC, and VA) and $16–$40 billion in damage. Seventy-seven percent (77%) of the fatalities occurred in the [...] Read more.

Florence made landfall on the southeastern coast of North Carolina (NC) generating torrential rainfall and severe flooding that led to 53 fatalities in three states (NC, SC, and VA) and $16–$40 billion in damage. Seventy-seven percent (77%) of the fatalities occurred in the rural flood plains of NC with Duplin county reporting a high of eight deaths. Approximately 50% of the total number of hurricane-related fatalities across the three states were vehicle-related. The predominant demographic at risk were males over the age of 50 years. The type of property damage was in line with other major hurricanes and predominantly affected residential structures (93% of the total number of damaged buildings). Florence is among the top 10 costliest hurricanes in U.S. history with approximately 50% of the damage projected as uninsured losses due to residential flooding. The cumulative 5-day rainfall resulted in major flooding along the Cape Fear, Lumberton, and Neuse rivers where many industrial waste sites (hog manure lagoons and coal ash pits) are located. Several of these waste sites located in the flood plain were breached and have likely cross-contaminated the waterways and water treatment operations. The observed extent of the flooding, environmental contamination, and impact to public health caused by Florence will add to the long-term disaster related mortality and morbidity rates and suggests an expansion of the 100-yr flood hazard zone to communicate the expanded risk to the public. Full article

(This article belongs to the Special Issue Impacts of Compound Hydrological Hazards or Extremes)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Impacts of Compound Hydrological Hazards or Extremes

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Related Special Issues

Published Papers (8 papers)

Editorial

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI