Flood Hazard Mapping Research Articles

Multi-Hazard Analysis in Gunungkidul Regency Using Spatial Multi-Criteria Evaluation

This study has two aims: to determine the spatial distribution of multi-hazard levels and to discover the interactions, interdependencies, and effects that cascade among hazards in Gunungkidul Regency, Special Region of Yogyakarta. A multi-hazard map was created with a scale of 1:250,000 and modelled using SMCE (Spatial Multi-Criteria Evaluation). The conditioning factors used included slope, rainfall, historical data, river distance, geomorphology, land cover, lithology, and fault distance. The selected conditioning factors for each hazard were then weighted using weighted overlay analysis. The results showed that the area of Gunungkidul can be included in the high-risk category for floods, since the probability of flooding is 56.72%, the probability of landslides is 9.14%, that of drought is 48.86%, and that of seismic disturbance is 20.83%. (Multi-hazard maps are created by overlaying flood, landslide, seismic, and drought hazard maps.) After these risk factors were calculated, the regions on the multi-hazard map were re-categorized into five hazard classes. All areas in Gunungkidul Regency have multiple hazards, with risk factors of different magnitudes. The interaction between hazards can generate new hazards that are called cascading hazards. The cascading hazards in the study area are most likely to occur in the north of Gunungkidul Regency with its very high seismic and landslide hazard risk factors, due to the geological and geomorphological conditions of the Baturagung Structural Hills.

Analisis Konservasi Kawasan Banjir Di Kota Bandung: Studi Kasus Kecamatan Sukasari

This research aims to analyze the conservation or solutions to flood disaster problems as a community need with a healthy environment. The research was conducted in Sukasari District, Bandung City, West Java Province, with an area of 6.27 km2. The method used in this paper is descriptive analysis and the data used is secondary data. Based on the analysis of the flood hazard map for Bandung City, the research results show that the entire area of Sukasari District is highly prone to flooding. Based on the findings, the overflow of the Cidurian, Cipamokolan, and Cibeureum rivers poses a threat of flooding in Sukasari sub-district. Green Open Spaces in Sukasari District consist of 16 location points spread across 3 sub-districts. The utilization of Green Open Spaces serves to maintain ecosystem balance and increase the availability of clean air and water catchment areas. Solutions to reduce flood disasters include reducing the level of risk, decreasing vulnerability, and enhancing community capacity.

Dampak Sosial Ekonomi Bencana Banjir dan Pemetaannya Berbasis Sistem Informasi Geografis (SIG)

The purpose of this study was to determine the distribution of flood locations in the Rokan Hulu regional administrative area and to determine the socio-economic impact of flooded households by modeling the distribution of flood locations based on Geographic Information Systems (GIS). The population is residential residents of Rokan Hulu Regency and floodplain sampling points located in the floodplains. The possibility of a flood disaster in Rokan Hulu Regency is very vulnerable and is divided into 16 districts. The research data was evaluated using point analysis method. There are two types of spatial mapping used, namely spatial mapping and spatial overlay. Spatial mapping is a description of conditions on a map, while spatial overlay is an analysis of several maps to create a new map. This mapping produces a flood hazard map, as well as a combination of point analysis and coverage analysis.

Dam Break Flood Mapping and Analysis Using Open Source GIS Tool and Data

The impact of climate change may influence on extreme weather conditions and may lead to high intensity precipitation, which will impact on huge structures such as dam. Although risk mitigation and protection of dams from advanced technical expertise have been reviewed regularly, a maximum non-risk guarantee is not achievable, and incidents may occur due to water that usually flows over a spillway and high-speed discharge or unexpected peak discharge. Hence, the immediate impact of dam failure is on the population at risk near the downstream area. This study evaluates the impact of dam break scenario under probable maximum precipitation (PMF) condition at Puah hydropower dam. The aims of this study are to determine the potential risk area at downstream and to assess the flooding impact on population and public facilities due to dam break event. Integration of an open source GIS tool, Google Satellite Image, Open Street Map, and flood hazard map derived from hydrodynamic model has been used to efficiently analyse the impact of dam break flood by using spatial analysis method, and to generate possible evacuation route network. Analysis has estimated that 187,796 people at risk, 3,177 km of road, 2-unit hospital and 76 amenities (mosque and school) will be impacted. This study portrays the possibility of using open source data and tool as an alternative for emergency preparedness application. The method used in this study could be adopted to other area of interest and disaster event, helping the local authorities for disaster emergency preparedness and early warning systems focusing on rescue work if disaster occurs.

Flood hazard mapping using M5 tree algorithms and logistic regression: a case study in East Black Sea Region

Flood hazard mapping using M5 tree algorithms and logistic regression: a case study in East Black Sea Region

Development of A Web based GIS Solution for Flood Inundation Mapping and Assessment in Lahore, Pakistan

Introduction Geographic information system (GIS) is a strong tool in flood hazard mapping, mitigation, and management. GIS-based approach provides the capability to measure the flood inundation. Integration of web technologies with GIS (Web-GIS) is quite significant to accomplish the aim. Methodology In this research, HEC-RAS 1D was used to map the flooded area around River Ravi at Lahore. The output of HEC-RAS with Web-GIS stack were used to build the interactive flood measuring tool. The Web-GIS stack used for this study was Geo Server, PHP, HTML, CSS, and JavaScript. Geo Server provides the OGC implemented standards with vendor specific capabilities like WMS Animator in Geo Server animate the flood inundation on the User-Interface (UI) and extent animation to make visual interpretations. CQL filter is vendor specific capability in Geo Server used to measure the flood inundation. Results The Output maps of HEC-RAS are capable enough to understand flood inundation and other damage assessments not only to analyst but also the layman. The working and animated layers are shown in Result section of this research. Conclusion This web-based flood inundation is robust, user-friendly, and expandable for more features, scenarios, and conditions. This research concludes that visual and web-based data is near to mind understanding for common person intellectuals.

PEMANFAATAN DATA PENGINDERAAN JAUH DAN SISTEM INFORMASI GEOGRAFIS (SIG) UNTUK ANALISA BANJIR (STUDI KASUS: KECAMATAN WANAREJA KABUPATEN CILACAP)

Wanareja Subdistrict is one of 24 subdistricts in Cilacap Regency which experiences floods every year. In 2022, until September, Wanareja District will experience four floods. Utilization of remote sensing and Geographic Information Systems (GIS) can be used to determine the level of vulnerability to flood disasters. This study aims to process the parameters that cause flooding and create a flood hazard map using Geographic Information System (GIS) aplikasi. The method used is scoring, weighting, and overlaying the parameters that cause flooding, namely land use, rainfall, slope, altitude, soil type, and river buffer which are processed using the ArcGIS 10.8 application. The results of this study are in the form of a flood vulnerability map which shows that Wanareja District has three levels of flood vulnerability, namely safe, low, and moderate. The low vulnerability level is the area that has the largest area, namely 9927.26 Ha (52%), while the medium vulnerability level is 7254.53 Ha (38%), and the safe vulnerability level has the smallest area, namely 1909.09 Ha (10%) of the total area in the Wanareja District of 19090.88 Ha

Flooding in the Digital Twin Earth: The Case Study of the Enza River Levee Breach in December 2017

The accurate delineation of flood hazard maps is a key element of flood risk management policy. Flood inundation models are fundamental for reproducing the boundaries of flood-prone areas, but their calibration is limited to the information available on the areas affected by inundation during observed flood events (typically fragmentary photo, video or partial surveys). In recent years, Earth Observation data have supported flood monitoring and emergency response (e.g., the Copernicus Emergency Service) thanks to the proliferation of available satellite sensors, also at high spatial resolution. Under this umbrella, the study investigates a levee breach that occurred in December 2017 along the Enza River, a right tributary of the Po River, that caused the inundation of a large area including Lentigione village. The flood event is simulated with a 2D hydraulic model using satellite images to calibrate the roughness coefficients. The results show that the processing and the timing of the high-resolution satellite imagery is fundamental for a reliable representation of the flooded area.

Modelling future flood events under climate change scenarios in the Pungwe River Basin

Abstract This study sought to project future changes in hydroclimatic variables and to establish how climate change affects flood inundation extent in the Pungwe River Basin. Climate ensembles of 10 Regional Climate Models from the CORDEX project were selected. The historical rainfall and temperature time series and the downscaled climate data were input into the HBV model to generate streamflow for the 2022–2099 period. Flood extents for 50-, 100-and 1,000-year return periods were predicted using the HEC-RAS hydraulic model. By 2070, annual rainfall at all nine studied meteorological stations is predicted to reduce by a maximum of 61%. Temperature is expected to increase up to 1.5% over the same period. By the 2070s, simulations from HBV revealed that the peak flows for the Pungwe River Basin will increase by up to 100% and decrease by approximately 57% as projected by the model ensemble. The analyses also show that by 2070 climate change may cause a minimum of 2,784.4 km2 and a maximum of 8,235.6 km2 of flood extension. These results are essential for decision-making on flood hazard mapping and early warning systems, prompting a pathway for sustainable development.

Methodology for constructing a flood-hazard map for a future climate

Abstract. Flooding is a major natural hazard in many parts of the world, and its frequency and magnitude are projected to increase with global warming. With increased concern over ongoing climate change, more detailed and precise information about climate-change risks is required for formulating local-scale countermeasures. However, the impacts of biases in climate-model outputs on river-flood simulation have not been fully evaluated, and thus evaluation of future flood risks using hazard maps (high-resolution spatial-distribution maps of inundation depths) has not been achieved. Therefore, this study examined methods for constructing future-flood-hazard maps and discussed their validity. Specifically, we compared the runoff-correction method that corrects for bias in general-circulation-model (GCM) runoff using the monthly climatology of reanalysis runoff with the lookup method, which uses the GCM simulation results without bias correction to calculate changes in the return period and depends on the reanalysis simulation to determine absolute flood depths. The results imply that the runoff-correction method may produce significantly different hazard maps compared to those based on reanalysis of runoff data. We found that, in some cases, bias correction did not perform as expected for extreme values associated with the hazard map, even under the historical climate, as the bias of extreme values differed from that of the mean value. We found that the change direction of a future hazard (increase or decrease) obtained using the runoff-correction method relative to the reference reanalysis-based hazard map may be inconsistent with changes projected by Catchment-based Macro-scale Floodplain Model (CaMa-Flood) simulations based on GCM runoff input in some cases. On the other hand, the lookup method produced future-hazard maps that are consistent with flood-hazard changes projected by CaMa-Flood simulations obtained using GCM runoff input, indicating the possibility of obtaining a reasonable inundated-area distribution. These results suggest that the lookup method is more suitable for future-flood hazard-map construction than the runoff-correction method. The lookup method also has the advantage of facilitating research on efficient construction of future-climate hazard maps, as it allows for improvement of the reanalysis hazard map through upgrading of the model and separate estimation of changes due to climate change. We discuss future changes at the global scale in inundation areas and the affected population within the inundation area. Using the lookup method, the total population living in modeled inundation areas with flood magnitudes exceeding the 100-year return period under a future climate would be approximately 1.86 billion. In the assessment of future-climate risks, we found that an affected population of approximately 0.2 billion may be missed if the historical-hazard map is used as an alternative to constructing future-hazard maps, and only frequency changes are considered. These results suggest that, in global flood-risk studies, future-hazard maps are important for proper estimation of climate-change risks rather than assessing solely changes in the frequency of occurrence of a given flood intensity.

Impact of Climate Change and Land Use Change on Coastal Areas: A Case Study Thane, India

Changes in land use patterns and increased occurrence of extreme rainfall events and sea level rise are now serious concerns for urban coastal flooding. Thane city faces frequent flooding problem every monsoon and now its frequency and inundation area are increasing. Therefore, the objective of this study is to develop a flood hazard map taking into account the combined effect of land use change and climate change. In this study, the effects of land use land cover (LULC) changes over the past 25 years (1995-2020) and for next 30 years were examined. The obtained result indicates that since 1995 the built-up area has increased by 27.47% in past 25 years, and it will further increase up to 55.99 % for next 30 years. It means that Thane city is rapidly urbanizing. The increasing built-up area and increasing rainfall intensity events and sea level rises, increases the peak runoff. The obtained result in present study indicates that peak runoff in past 25 years due to land use changes increased by 11.5% and it will further increase up to 31.8 % for next 30 years including climate change effect. This means that Thane city has faced water logging problem in the past and will face water logging problem in the future. In the present study, Storm CAD software was used for hydraulic analysis of major drains while ArcGIS software was used for land use change analysis, flood prone area development and flood hazard mapping. The result of this analysis indicates that inundation area in past 25 years increased to 9.15% and it will further increase up to 14.03 % for next 30 years. This means that Thane city currently facing waterlogging problem in 6.211 km2 and will face waterlogging problem up to 9.604 km2 in future. It is expected that the developed flood hazard map may assist decision-makers or/to relevant authorities, particularly for storm water planning and water-related concerns to minimize the number of lives and property lost due to repetitive flood disasters in Thane city.

Extreme Weather Events: The Impact of Flooding on Transportation Network: Case Study of Buyukcekmece Basin

Transportation is a critical sector which is vulnerable to hazardous events like urban floods. Thedisruption in transportation infrastructure affects the whole community in terms of loss of life and property.A resilient transport system is fundamental for resilient communities, and considering the adverse impactsof climate change, it becomes even more important. The Büyükçekmece Basin is a densely populated andeconomically significant area that also includes regions of natural importance requiring preservation. Thus,a flood hazard can affect more people, cause greater monetary losses and have negative impact on theenvironment and nature.The purpose of this research is to present the disruption of road network in Büyükçekmece Basin due toflooding and create an analytical framework. Vulnerability of road systems to rainfall-induced floods isquantified by integrating different models. An integrated framework linking hydrological model andinundation model is established and the relation between flood depth and road network vulnerability isdetermined. Flood hazard maps are created for two different rainfall events with 1 in 50 year and 1 in 100-year return period and flooded road lengths are determined. The flood levels have shown that there are roadsegments that will face moderate and major flooding. In Büyükçekmece Basin where serious floods haveoccurred in the past, measures need to be taken regarding the road network for possible flood risks.

GIS-based flood risk assessment using multi-criteria decision analysis of Shebelle River Basin in southern Somalia

Floods are the most common and expensive natural calamity, affecting every country. Flooding in the Shebelle River Basin (SRB) in southern Somalia has posed a significant challenge to sustainable development. The main goal of this study was to analyze flood hazard, vulnerability and risk in the part of SRB using GIS-based Multi-Criteria Decision Analysis (MCDA). The flood hazard map was constructed using seven important causative factors: elevation, slope, drainage density, distance to river, rainfall, soil and geology. The results demonstrate that very low, low, moderate, high, and very high flood hazard zones correspond to 10.92%, 24.97%, 29.13%, 21.93% and 13.04% of the area of SRB, respectively. The flood vulnerability map was created using five spatial layers: land use/land cover, population density, distance to road, Global man-made impervious surface (GMIS), and Human built-up area settlement extent (HBASE). In addition, the results of the flood susceptibility and vulnerability maps were used to create a flood risk map. The results demonstrate that for the Shebelle River Basin, 27.6%, 30.9%, 23.6%, 12.1%, and 5.7% area correspond to very low, low, moderate, high, and very high flood risk zones, respectively. The Receiver Operating Characteristics-Area Under the Curve (ROC-AUC) of the flood hazard model exhibited a good prediction accuracy of 0.781. The majority of the basin is at risk of flooding in the very low, low, and moderate ranges; however, some tiny areas are at risk of flooding in the high and very high ranges. Flood hazard, vulnerability and risk maps should be provided and distributed the authorities responsible for flood protection so that people are aware flood risk locations.

Multi Hazard Analysis of Ponorogo Regency Disaster Based on Geographic Information System

Ponorogo regency has dangers to several types of disasters such as floods, landslides, tornadoes, land fires, and droughts. Based on data from BNPD from the period 2000 - 2020, Ponorogo Regency has experienced 123 landslides, and 39 flood disasters. The approach used in this study is multi-hazard disaster. The purpose of the study is 1.) Analyze the spread of flood hazard levels in Ponorogo Regency. 2.) Analyze the spread of the danger level of landslide disasters in Ponorogo Regency.3.) Analyze the distribution of disaster hazard levels in Ponorogo Regency using a multi hazard index. The research methods conducted in this study are stacking and improvement, while for multi-hazard modeling of disasters using VCA tables. Data processing in this study is divided into 3 stages, namely parameter data processing, disaster hazard data modeling, and multi-hazard disaster modeling. The accuracy test is conducted on the usage data, and the sampling method is a random sampling method. Validation tests were conducted on data from modeling the hazards of floods and landslides. The results of this study are a disaster parameter data map, a flood hazard map, a landslide hazard map, and a multi-hazard disaster map. Based on the results of modeling, multi-hazard disaster has an area that is low hazard class has the widest area of 90,773.55 Ha (65%), The moderate hazard class has an area of 45,438.55 Ha (33%). The high hazard class has an area of 2,957.56 Ha (12%). The multi-hazard class is determined by the result of a combination of landslide and flood hazard classes, for example the combination of low and high hazard classes will produce a moderate hazard class. Therefore, the distribution of areas from the multi-hazard class of disasters is greatly influenced by the distribution of areas of both types of disasters.

Flood Hazard Zoning of Upper Awash River Basin, Ethiopia, Using the Analytical Hierarchy Process (AHP) as Compared to Sensitivity Analysis.

Floods and droughts have been two of the most devastating consequences of the climate crisis affecting billions of people in the world. However, unlike the other natural hazards, flooding is manageable through appropriate flood management mechanisms. This study emphasizes on developing a flood hazard zone for the Upper Awash River Basin (UARB), Ethiopia. Six relevant climate, physiographic, and biophysical factors were considered. Then, a flood hazard map was developed employing the analytic hierarchy process (AHP) method and further validated using sensitivity analysis and collected flood marks. The results revealed that drainage density, rainfall, and elevation have higher significance, while land use and soil permeability have a low impact in the process of flood generation. The map showed vulnerable areas at different levels and can serve as a valuable input for the decision makers to consider in the process of implementing emergency plans as well as long-term flood mitigation options.

Probabilistic mapping and sensitivity assessment of dam-break flood hazard

ABSTRACT Quantitative assessment of dam-break flood hazard is central in dam emergency action planning and is typically performed deterministically. In structural failure of concrete or masonry dams the collapse is assumed to be total and instantaneous, with the reservoir level at the spillway crest level. A probabilistic method is here proposed based on a set of dam-break scenarios characterized by different breach widths and reservoir levels in order to provide an appraisal of uncertainties in flood hazard indicators. Each scenario is attributed a weight, defined as a conditional probability given a dam-break event. Probabilistic flood hazard and inundation maps are produced for the case study of the hypothetical collapse of the Mignano dam (River Arda, northern Italy), and a sampling-based global sensitivity analysis is performed. Dam-break flooding was simulated using a two-dimensional hydrodynamic model on a high-resolution mesh. The probabilistic maps inherently provide quantitative information on the uncertainty of dam-break flood hazard.

Flood hazard map of the Becho floodplain, Ethiopia, using nonstationary frequency model

Flood hazard map of the Becho floodplain, Ethiopia, using nonstationary frequency model

Application of Remote Sensing and Geographical Information System (GIS) in Flood Vulnerability Mapping: A Scenario of Akure South, Nigeria

In flooding, dry land capable of residential, agricultural, and other economic activities is submerged by overflowing water. This causes loss of lives, properties, and destruction of infrastructure. This study applies remote sensing and GIS techniques to produce a flood vulnerability map of the Akure South metropolis. For this study, satellite image data (Landsat 8), location map of Akure South metropolis, SRTM DEM, rainfall data, soil data, and GPS coordinates; acquired during the field survey were integrated to map areas vulnerable to flooding. Using Pairwise Comparison, the various weights of factors constituting flood in the area were acquired. A weighted linear combination and analytical hierarchical process were used to produce the flood hazard and flood vulnerability map. ArcGIS Pro 2.7.3 software was used in spatial and attribute data acquisition, processing, and information presentation. The flood vulnerability results indicated that the very high vulnerability zone occupied 13.9% of the study area, while high vulnerability zone occupied 25.5%. Moderate vulnerability zone occupied 36.8% while low vulnerability zone occupied 23.8% of the study area. The study shows that, remote sensing and GIS can be effectively implemented to analyse and provide results on flood vulnerability required for prompt and effective decision-making on floods.

Two-Dimensional Modelling for Dam Break Analysis and Flood Hazard Mapping: A Case Study of Papadia Dam, Northern Greece

Dams are expensive technical constructions that ensure food production, sustain farmers’ income, and cover a large percentage of urban water supply demands. However, the threat of a dam break flood, which can be extremely dangerous for the local society, should be taken into account, and proactive mitigation measures should be planned. Towards this direction, dam break modelling and flood hazard assessment are essential for developing flood crisis management and evacuation plans. In this study, a hypothetical case of failure of the Papadia dam in the Florina Regional Unit in northern Greece is examined. Two scenarios of failure were considered: overtopping and piping. A two-dimensional numerical model for the two failure scenarios was used to simulate the dam break process and flood wave routing using HEC-RAS software. A sensitivity analysis of the mesh size and breach parameters was performed to better understand their impact on the critical outputs of the simulation model. Flood hazard maps were produced in GIS environment based on water depth and velocity criteria. Furthermore, two classification approaches were adopted to assess the flood hazard using the product of water depth and velocity. The results showed that the extent of the inundated area could affect most of the study area and could cause severe damage to agricultural activities.

Dam failure analysis and flood disaster simulation under various scenarios.

The aim of this study is to analyze the effects of a possible dam failure under various scenarios and to generate a flood hazard map for two consecutive dams located in a study area with a dense-residential region and a heavy-traffic highway. Two consecutive dams consist of Elmalı 2, a concrete-buttress dam and Elmalı 1, an earth-fill gravity dam in the upstream and downstream, respectively. Hydrologic Engineering Center-River Analysis System (HEC-RAS) was used to develop a dam failure model. Dam failure scenarios were examined regarding three main criteria: the Breach Formation Time (BFT), the Number of Failed Buttresses (NFB) of Elmalı 2, and the Reservoir Volume Ratio (RVR) of Elmalı 1. Accordingly, flood peak depth (Hp), peak flow rate (Qp), peak velocity (vp), and time to reach the peak (tp) are discussed. The results showed that BFT and NFB of Elmalı 2 were highly effective on these values, whereas RVR of Elmalı 1 had no significant effect. Moreover, the total area affected by potential floods was calculated with a comparative areal change analysis using flood inundation and flood hazard maps obtained. Estimated damage costs indicate that in the worst-case scenario, more than 500 buildings will be affected in the region.