scholarly journals Combining SAR and Optical Earth Observation with Hydraulic Simulation for Flood Mapping and Impact Assessment

2020 ◽  
Vol 12 (23) ◽  
pp. 3980
Author(s):  
Emmanouil Psomiadis ◽  
Michalis Diakakis ◽  
Konstantinos X. Soulis
Keyword(s):  
Impact Assessment ◽  
Temporal Dynamics ◽  
Flood Hazard ◽  
Recurrence Interval ◽  
Optical Data ◽  
Flood Event ◽  
Flood Events ◽  
Hydraulic Modelling ◽  
Flood Impact ◽  
Flood Characteristics

Timely mapping, measuring and impact assessment of flood events are crucial for the coordination of flood relief efforts and the elaboration of flood management and risk mitigation plans. However, this task is often challenging and time consuming with traditional land-based techniques. In this study, Sentinel-1 radar and Landsat images were utilized in collaboration with hydraulic modelling to obtain flood characteristics and land use/cover (LULC), and to assess flood impact in agricultural areas. Furthermore, indirect estimation of the recurrence interval of a flood event in a poorly gauged catchment was attempted by combining remote sensing (RS) and hydraulic modelling. To this end, a major flood event that occurred in Sperchios river catchment, in Central Greece, which is characterized by extensive farming activity was used as a case study. The synergistic usage of multitemporal RS products and hydraulic modelling has allowed the estimation of flood characteristics, such as extent, inundation depth, peak discharge, recurrence interval and inundation duration, providing valuable information for flood impact estimation and the future examination of flood hazard in poorly gauged basins. The capabilities of the ESA Sentinel-1 mission, which provides improved spatial and temporal analysis, allowing thus the mapping of the extent and temporal dynamics of flood events more accurately and independently from the weather conditions, were also highlighted. Both radar and optical data processing methods, i.e., thresholding, image differencing and water index calculation, provided similar and satisfactory results. Conclusively, multitemporal RS data and hydraulic modelling, with the selected techniques, can provide timely and useful flood observations during and right after flood disasters, applicable in a large part of the world where instrumental hydrological data are scarce and when an apace survey of the condition and information about temporal dynamics in the influenced region is crucial. However, future missions that will reduce further revisiting times will be valuable in this endeavor.

scholarly journals Building hazard maps with differentiated risk perception for flood impact assessment

2020 ◽  
Vol 20 (10) ◽  
pp. 2647-2663
Author(s):  
Punit K. Bhola ◽  
Jorge Leandro ◽  
Markus Disse
Keyword(s):  
Risk Perception ◽  
Impact Assessment ◽  
Flood Hazard ◽  
Flood Forecasting ◽  
Exceedance Probability ◽  
Generation Process ◽  
Hazard Maps ◽  
Flood Impact ◽  
The Impact ◽  
Flood Hazard Maps

Abstract. In operational flood risk management, a single best model is used to assess the impact of flooding, which might misrepresent uncertainties in the modelling process. We have used quantified uncertainties in flood forecasting to generate flood hazard maps that were combined based on different exceedance probability scenarios. The purpose is to differentiate the impacts of flooding depending on the building use, enabling, therefore, more flexibility for stakeholders' variable risk perception profiles. The aim of the study is thus to develop a novel methodology that uses a multi-model combination of flood forecasting models to generate flood hazard maps with differentiated exceedance probability. These maps take into account uncertainties stemming from the rainfall–runoff generation process and could be used by decision makers for a variety of purposes in which the building use plays a significant role, e.g. flood impact assessment, spatial planning, early warning and emergency planning.

scholarly journals FLOOD HAZARD MAPPING OF BOGOWONTO RIVER IN PURWOREJO REGENCY, CENTRAL JAVA PROVINCE

2017 ◽  
Vol 2 (3) ◽  
pp. 243 ◽  
Author(s):  
Margaretha Titi Pawestri ◽  
Joko Sujono ◽  
Istiarto Istiarto
Keyword(s):  
Flood Hazard ◽  
Hazard Mapping ◽  
Flood Inundation ◽  
Hazard Maps ◽  
Flood Events ◽  
Hydraulic Modelling ◽  
Surrounding Area ◽  
Huge Amount ◽  
Central Java ◽  
Starting Point

The overflowing discharge of Bogowonto River in Purworejo Regency, Central Java flooded the surrounding area during the rainy season. A huge amount of losses such as damage of infrastructures, housing, and agricultural area occurs every year. This research mainly aims to develop flood hazard map and study the characteristics of flood in the study area. There are two main analysis; hydrologic and hydraulic, to model a flood event. Hydrologic and hydraulic modelling of flood based on 20 and 50- years return period hydrograph along the river geometryis done using the latest HEC program namely HEC- HMS 4.1 and HECRAS 5.0. Also, ArcGIS 10.3 is used as a terrain pre-processor and post-processor for hazard mapping. The results of this research are flood hazard maps for 20 and 50 years flood and its comparison to the recent major flood events. Flood inundation modelled covered an area of 993.77 Ha and 1,175.86 Ha, with maximum discharge calculated at Boro Weir as starting point are 1206.2 m3/s and 1,397.3 m3/s for 20 and 50 years flood case, respectively.

scholarly journals Environmental Impact Assessment and Hydraulic Modelling of Different Flood Protection Measures

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 786
Author(s):  
Andrej Šoltész ◽  
Martina Zeleňáková ◽  
Lea Čubanová ◽  
Mária Šugareková ◽  
Hany Abd-Elhamid
Keyword(s):  
Environmental Impact ◽  
Impact Assessment ◽  
Environmental Impact Assessment ◽  
Slovak Republic ◽  
Flood Hazard ◽  
Flood Protection ◽  
Mitigation Measures ◽  
Hydraulic Modelling ◽  
Protection Measure ◽  
Protection Measures

The most appropriate method to protect settlements and economically important sites from flood hazard, is the implementation of flood protection measures in stream catchments and protected localities, which contribute to reduce the peak flow and distribution of the flood wave over a longer period of time. If such measures are not realistic or ineffective, it is necessary to focus on flood protection directly on the area of the protected side or its vicinity. Where the lag time between the flood threat detection and actual flood onset is short, one possible measure is to increase the capacity of the watercourse, very often in combination with other flood mitigation measures in the protected area. The engineering approach to flood protection is the subject of many scientific research studies. Permission for flood protection structures depends on their environmental impact assessment (EIA), according to Law no. 24/2002 Coll. on Environmental Impact Assessment in the Slovak Republic, annex no. 8 (list of activities subject to EIA). Based on the EIA, it is possible to select the best alternative of flood protection, i.e., the alternative with the lowest risk impact on the environment. This paper aims to analyse the flood protection measures along the Lukavica stream (central Slovakia), applying hydraulic models. The best alternative with the lowest impact on the environment, assessed using the risk analysis method, consists of detention reservoir construction. An effective combination of environmental impact assessment and hydraulic modelling contribute to the selection of an effective flood protection measure in the territory.

scholarly journals CONSIDERATIONS ON THE USE OF SENTINEL-1 DATA IN FLOOD MAPPING IN URBAN AREAS: ANKARA (TURKEY) 2018 FLOODS

2018 ◽  
Vol XLII-5 ◽  
pp. 575-581 ◽  
Author(s):  
B. Tavus ◽  
S. Kocaman ◽  
C. Gokceoglu ◽  
H. A. Nefeslioglu
Keyword(s):  
Urban Areas ◽  
City Planning ◽  
Flood Hazard ◽  
Flood Event ◽  
Optical Remote Sensing ◽  
Infrastructure Development ◽  
Flood Events ◽  
Rapid Urbanization ◽  
Mapping Procedure ◽  
Synthetic Aperture Radar Data

<p><strong>Abstract.</strong> Flood events frequently occur due to -most probably- climate change on our planet in the recent years. Rapid urbanization also causes imperfections in city planning, such as insufficient considerations of the environmental factors and the lack of proper infrastructure development. Mapping of inundation level following a flood event is thus important in evaluation of flood models and flood hazard and risk analyzes. This task can be harder in urban areas, where the effect of the disaster can be more severe and even cause loss of lives.</p><p>With the increased temporal and spatial availability of SAR (Synthetic Aperture Radar) data, several flood detection applications appear in the literature although their use in urban areas so far relatively limited. In this study, one flood event occurred in Ankara, Turkey, in May 2018 has been mapped using Sentinel-1 SAR data. The preprocessing of Sentinel-1 data and the mapping procedure have been described in detail and the results have been evaluated and discussed accordingly. The results of this study show that SAR sensors provide fast and accurate data during the flooding using appropriate methods, and due to the nature of the flood events, i.e. heavy cloud coverage, it is currently irreplaceable by optical remote sensing techniques.</p>

scholarly journals Hazard maps with differentiated exceedance probability for flood impact assessment

2019 ◽  
Author(s):  
Punit Kumar Bhola ◽  
Jorge Leandro ◽  
Markus Disse
Keyword(s):  
Impact Assessment ◽  
Flood Hazard ◽  
Flood Forecasting ◽  
Exceedance Probability ◽  
Generation Process ◽  
Hazard Maps ◽  
Runoff Generation ◽  
Model Combination ◽  
Flood Impact ◽  
The Impact

Abstract. In operational flood risk management, a single best-model is used to assess the impact of flooding, which might misrepresent uncertainties in the modelling process. We have used quantified uncertainties in flood forecasting to generate flood hazards maps that were combined based on exceedance probability scenarios. The purpose is to differentiate the impact of flooding depending on the building use. The aim of the study is thus to develop a novel methodology that uses a multi-model combination of flood forecasting models to generate flood hazard maps with differentiated exceedance probability. These maps take into account uncertainties steaming from the rainfall-runoff generation process and could be used by decision-makers for a variety of purposes in which the building use plays a significant role, e.g. flood impact assessment, spatial planning, early warning and emergency planning.

scholarly journals Urban Flood Modeling Using 2D Shallow-Water Equations in Ouagadougou, Burkina Faso

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2120
Author(s):  
Gnenakantanhan Coulibaly ◽  
Babacar Leye ◽  
Fowe Tazen ◽  
Lawani Adjadi Mounirou ◽  
Harouna Karambiri
Keyword(s):  
Shallow Water ◽  
Shallow Water Equations ◽  
Urban Areas ◽  
Flood Hazard ◽  
Scientific Information ◽  
Roughness Coefficient ◽  
Flood Events ◽  
African Countries ◽  
Numerical Tool ◽  
2D Shallow Water Equations

Appropriate methods and tools accessibility for bi-dimensional flow simulation leads to their weak use for floods assessment and forecasting in West African countries, particularly in urban areas where huge losses of life and property are recorded. To mitigate flood risks or to elaborate flood adaptation strategies, there is a need for scientific information on flood events. This paper focuses on a numerical tool developed for urban inundation extent simulation due to extreme tropical rainfall in Ouagadougou city. Two-dimensional (2D) shallow-water equations are solved using a finite volume method with a Harten, Lax, Van Leer (HLL) numerical fluxes approach. The Digital Elevation Model provided by NASA’s Shuttle Radar Topography Mission (SRTM) was used as the main input of the model. The results have shown the capability of the numerical tool developed to simulate flow depths in natural watercourses. The sensitivity of the model to rainfall intensity and soil roughness coefficient was highlighted through flood spatial extent and water depth at the outlet of the watershed. The performance of the model was assessed through the simulation of two flood events, with satisfactory values of the Nash–Sutcliffe criterion of 0.61 and 0.69. The study is expected to be useful for flood managers and decision makers in assessing flood hazard and vulnerability.

scholarly journals Spatial-temporal trends analysis of flood events in the Republic of Armenia in the context of climate change

2020 ◽  
Vol 11 (S1) ◽  
pp. 289-309 ◽  
Author(s):  
Hrachuhi Galstyan ◽  
Shamshad Khan ◽  
Hovik Sayadyan ◽  
Artur Sargsyan ◽  
Tatevik Safaryan
Keyword(s):  
Climate Change ◽  
Flood Hazard ◽  
Methodological Approach ◽  
Temporal Trends ◽  
Geographical Information ◽  
Trend Test ◽  
Flood Events ◽  
Temperature And Precipitation ◽  
The Republic ◽  
Events Data

Abstract The primary goal of the study is to analyze the spatial-temporal trends and distribution of flood events in the context of climate change in Armenia. For that purpose, some meteorological parameters, physical-geographical factors and the flood events data were studied for the 1994–2019 period. The linear trends demonstrate an increasing tendency of air temperature and precipitation. Those trends expressed increased flood occurrences, especially for the 2000s, whereas the Mann–Kendall (MK) trend test reveals no significant change. The number of flood events reaches its maximum in 2011 with its peak in May. Out of 191 flood events, half of the occurrences are recorded in the flat areas and southern aspects of the mountains (22% of the country's territory). There is a certain clustering of flood events in the areas with up to 5° slopes (66% of flood events). The most flood vulnerable areas were analyzed and mapped via Geographical Information System (GIS). The GIS-based mapping shows the location of flood vulnerable areas in the central, northern parts of the country, and the coastal areas of Lake Sevan. Our methodological approach elaborates the localization of flood-prone sites. It can be used for the flood hazard assessment mapping and risk management.

scholarly journals Quantifying Landscape Structure of the Kelantan River Basin Before and After a Major Flood Event Using Landscape Metrics

2021 ◽  
pp. 61-67
Author(s):  
H.Y. Abdul
Keyword(s):  
River Basin ◽  
Land Use Planning ◽  
Landscape Structure ◽  
Monsoon Season ◽  
Integrated Approach ◽  
Flood Event ◽  
Northeast Monsoon ◽  
Flood Events ◽  
Kelantan River Basin ◽  
The Impact

Over the years, flood is one of the natural hazards which occur all over the world and it is critical to be controlled through proper management. Flood in Kelantan is mainly caused by heavy rainfall brought by the Northeast monsoon starting from November to March every year. It is categorized as annual flood as it occurs every year during the Monsoon season. Severe flood events in Kelantan, Malaysia cause damage to both life and property every year and understanding landscape structure changes is very important for planners and decision makers for future land use planning and management. This research aims to quantify the landscape structure near to Kelantan River basin during the flood event using integrated approach of remote sensing (RS), geographic information system (GIS) technique and landscape ecological approach. As a result, this study provide new knowledge on landscape structure that contributes to understand the impact of flood events and provide the best ways to mitigate flooding for helping to protect biodiversity habitat and dwellers. As conclusions, this kind of study will give more benefits to various stakeholders such as Department of Irrigation and Drainage, Department of Environment, state government, fisherman and communities.

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