Flood Mitigation Measures Research Articles

Urban flood response analysis for designed rainstorms with different characteristics based on a tracer-aided modeling simulation

The frequent occurrence of urban floods has severely affected urban public safety and restricted the sustainable development of the social economy. Studies have confirmed that extreme rainstorms are determining factors for the cause of urban floods. Additionally, the rainstorm pattern could be adopted to measure the temporal change in rainstorm intensity, and there may be differences in the process of urban flood, even if the rainstorm amount and return period are the same. The in-depth analysis of urban flood disaster levels in response to rainstorms with different characteristics is of substantial significance for managing unfavorable situations and implementing flood mitigation measures. Therefore, a tracer-aided urban flood model was developed to study the impact of rainstorm patterns on urban flooding. Based on the source tracking results, the direct and indirect connections were established between different areas of the urban system, their relative importance in the urban system was explored, and the response of urban flood processes to different rainstorm patterns from the perspective of flood source areas was analyzed. This study presents a modeling task for the Longkungou drainage district of Haikou City. Simulations were performed for 21 designed rainstorm events, in which the characteristic differences in rainstorm distribution are reflected in the return period, rainstorm patterns, and peak coefficients. The results indicate that in the case of the same rainstorm amount, the unimodal patterns, Modes II (middle peak) and III (late peak), are the most unfavorable situations for the flooded area. In addition, rainstorms with bimodal patterns also had different effects on the flood volume: Models VI and V had the largest and smallest flood volume, respectively. The source tracking results further showed that the formation of flood volume in the source area of the catchment is a comprehensive effect of regional characteristics and rainstorm patterns. The source area flood volume of catchments located upstream were not sensitive to the response of rainstorm patterns, and catchments in urban system with weaker drainage systems were more sensitive than that to the response of rainstorm patterns. This study provides theoretical insights for early warning of urban flooding, implementation of urban flood mitigation strategies, and flood risk management.

A satellite-based Standardized Antecedent Precipitation Index (SAPI) for mapping extreme rainfall risk in Myanmar

In recent decades, substantial efforts have been devoted in flood monitoring, prediction, and risk analysis for aiding flood event preparedness plans and mitigation measures. Introducing an initial framework of spatially probabilistic analysis of flood research, this study highlights an integrated statistical copula and satellite data-based approach to modelling the complex dependence structures between flood event characteristics, i.e., duration (D), volume (V) and peak (Q). The study uses Global daily satellite-based Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) (spatial resolution of ∼5 km) during 1981–2019 to derive a Standardized Antecedence Precipitation Index (SAPI) and its characteristics through a time-dependent reduction function for Myanmar. An advanced vine copula model was applied to model joint distributions between flood characteristics for each grid cell. The southwest (Rakhine, Bago, Yangon, and Ayeyarwady) and south (Kayin, Mon, and Tanintharyi) regions are found to be at high risk, with a probability of up to 40% of flood occurrence in August and September in the south (Kayin, Mon, and Tanintharyi) and southwest regions (Rakhine, Bago, Yangon, and Ayeyarwady). The results indicate a strong correlation among flood characteristics; however, their mean and standard deviation are spatially different. The findings reveal significant differences in the spatial patterns of the joint exceedance probability of flood event characteristics in different combined scenarios. The probability that duration, volume, and peak concurrently exceed 50th-quantile (median) values are about 60–70% in the regions along the administrative borders of Chin, Sagaing, Mandalay, Shan, Nay Pyi Taw, and Keyan. In the worst case and highest risk areas, the probability that duration, volume, and peak exceed the extreme values, i.e., the 90th-quantile, about 10–15% in the southwest of Sagaing, southeast of Chin, Nay Pyi Taw, Mon and areas around these states and up to 30% in the southeast of Dekkhinathiri township (Nay Pyi Taw). The proposed approach could improve the evaluation of exceedance probabilities used for flood early warning and risk assessment and management. The proposed framework is also applicable at larger scales (e.g., regions, continents and globally) and in different hydrological design events and for risk assessments (e.g., insurance).

Computation of backwater effects in surface waters of lowland catchments including control structures – an efficient and re-usable method implemented in the hydrological open-source model Kalypso-NA (4.0)

Abstract. Backwater effects in surface water streams and on adjacent lowland areas caused by mostly complex drainage and flow control structures are not directly computed with hydrological approaches yet. A solution to this weakness in hydrological modelling is presented in this article. The developed method enables transfer of discharges into water levels and calculation of backwater volume routing along streams and adjacent lowland areas by balancing water level slopes. The implemented and evaluated method extends the application of hydrological models for rainfall–runoff simulations of backwater-affected catchments with the advantages of (1) modelling complex flow control systems in tidal backwater-affected lowlands, (2) less effort to parameterise river streams, (3) directly defined input factors of driving forces (climate change and urbanisation) and (4) runtime reduction of 1 to 2 orders of magnitude in comparison to coupled hydrodynamic models. The developed method is implemented in the open-source rainfall–runoff model Kalypso-NA (4.0). Evaluation results show the applicability of the model for simulating rainfall–runoff regimes and backwater effects in an exemplary lowland catchment (Hamburg, Germany) with a complex flow control system and where the drainage is influenced by a tidal range of about 4 m. The proposed method is applicable to answer a wide scope of hydrological and water management questions, e.g. water balances, flood forecasts and effectiveness of flood mitigation measures. It is re-usable to other hydrological numerical models, which apply conceptual hydrological flood-routing approaches (e.g. Muskingum–Cunge or Kalinin–Miljukov).

A comprehensive analysis method of spatial prioritization for urban flood management based on source tracking

Flooding is one of the most frequent and disastrous natural hazards that can have catastrophic impacts on human society and urban infrastructure. Increasing the incidence of urban flooding highlights the need for reliable flood mitigation strategies that can effectively minimize losses owing to disasters. The strategic placement of flood mitigation measures is undoubtedly the key to achieving maximum effectiveness of flood reduction schemes. The physical characteristics of the site and knowledge of regional relevance play an important role in determining the location of appropriate flood mitigation measures. In the case of limited resources, it is crucial to prioritize areas for installation of flood mitigation measures. Therefore, an indicator-based method was developed in this study to identify and prioritize sites to concentrate limited resources where they are needed the most. Based on the source tracking method, a tracer-aided urban flood model was developed to study the impact of direct and indirect connections between urban systems, explore their relative importance in the network, and prioritize related risks to improve resource allocation efficiency. Longkungou drainage district of Haikou City was selected as the study area to determine the prioritization of catchments for flood mitigation. The results indicated that high prioritization sites are in the upstream of the urban areas with prioritization decreasing downstream, and the prioritization of interventions presents a spatial trend of “high south and low north”. This study demonstrates the novelty of a tracer-aided urban flood model in flood management and highlights the spatial connectivity between flood source areas and flood hazard areas. The prioritization scheme of urban catchment flood mitigation measures proposed in this study provides valuable guidance for policy makers and urban planners who wish to exploit the approach for flood mitigation.

Public risk perception and public acceptance of the existing flood and drought mitigation measure in Bandung city

Flood and drought are hydrometeorological hazard that annually occurred in Bandung City. This problem occurs due to static natural conditions such as geographical, topographical conditions, as well as dynamic natural conditions such as climatological matters that are exacerbated by climate change and human activities. Flood and drought risk management in urban areas generally emphasizes physical development by ignoring various social dimensions. Therefore, this research aims to understand people’s knowledge and attitudes towards disasters, represented by the public risk perception towards flooding and drought, as well as public acceptance of the existing programs that have been provided by the municipality. To identify public risk perception and their acceptance of existing programs use statistical descriptive methods. While the data collection use questionnaire with 99 samples. This research shows the affected communities can assess the risks, emotion, and expectation for the future risk, and the implemented program by municipality is mostly accepted by the community. Public risk perception and public acceptance of a program are prominent factors that determine the success or failure of a program by ensuring the compatibility of the program and the community. Thus, this research is critical to give the public perspective on implementing a community-based disaster mitigation program.

Flood frequency analysis and inundation mapping for lower Narmada basin, India

Abstract Floods are one of the world's most destructive natural disasters, taking more lives and causing more infrastructural damage than any other natural phenomenon. Floods have a significant economic, social, and environmental impact in developing countries like India. As a result, it is essential to address this natural disaster to mitigate its effects. The lower Narmada basin has experienced numerous floods, including severe flooding in 1970, 1973, 1984, 1990, 1994, and 2013. The objective of the present study is to use flood frequency analysis to anticipate peak floods and prepare flood inundation maps for the lower Narmada River reach. The flood frequency analysis was carried out using Gumbel's and Log-Pearson Type III Distribution methods. The hydrodynamic simulation was performed using HEC-RAS v6.0 to prepare flood inundation maps for predicted flood peaks. The result shows that the Log-Pearson Type-III distribution method gives good results for the lower return period while Gumbel's method gives good results for the higher return period. The hydrodynamic model results indicate that as the return period increases, the area of the high-risk zone increases while the area of the low-risk zone remains almost constant. The present study concludes that the existing embankment system on the banks of the Narmada River is not sufficient for significant floods. The developed maps will be helpful to government authorities and individual stakeholders to decide the flood mitigation measures.

Geophysical and Societal Dimensions of Floods in Manitoba, Canada: A Social Vulnerability Assessment of the Rural Municipality of St. Andrews

Being strongly influenced by the landscape of the Red River Valley, geophysical and a variety of sociodemographic and economic factors, the characteristics of floods are complex in the Province of Manitoba, Canada, which causes substantial loss and damage to lives and properties. The primary objectives of this study are two-fold: (i) to identify the geophysical and human-induced conditions of floods, and examine the trend in flood loss and damage in the Province of Manitoba, Canada; and (ii) to analyze the social vulnerability perspectives of floods in the Rural Municipality of St. Andrews, as a local community case study. Using the Delphi technique, primary data were procured from the field for community-level vulnerability analysis. Secondary data for a provincial-level analysis were collected from various public domains, including governmental departments and other non-government sources. The results reveal that a nested set of geophysical and societal factors determine the degree of vulnerability of individual community members. In Manitoba, it was found that socioeconomic damages caused by floods have increased considerably over time despite undertaking costly structural flood mitigation measures. We conclude that minimization of flood damages requires complementing structural measures with knowledge-sharing, collaboration among pertinent institutions, and the adoption of an interactive flood management system approach.

Stochastic Flood Risk Assessment under Climate Change Scenarios for Toronto, Canada Using CAPRA

Amongst all natural disasters, floods have the greatest economic and social impacts worldwide, and their frequency is expected to increase due to climate change. Therefore, improved flood risk assessment is important for implementing flood mitigation measures in urban areas. The increasing need for quantifying the impacts of flooding have resulted in the development of methods for flood risk assessment. The aim of this study was to quantify flood risk under climate change scenarios in the Rockcliffe area within the Humber River watershed in Toronto, Canada, by using the Comprehensive Approach to Probabilistic Risk Assessment (CAPRA) method. CAPRA is a platform for stochastic disaster risk assessment that allows for the characterization of uncertainty in the underlying numerical models. The risk was obtained by integrating the (i) flood hazard, which considered future rainfall based on the Representative Concentration Pathways (RCPs 2.6, 4.5, 6.0, and 8.5) for three time periods (short-term: 2020–2049, medium-term: 2040–2069, and long-term: 2070–2099); (ii) exposed assets within a flood-prone region; (iii) vulnerability functions, which quantified the damage to an asset at different hazard levels. The results revealed that rainfall intensities are likely to increase during the 21st century in the study area, leading to an increase in flood hazards, higher economic costs, and social impacts for the majority of the scenarios. The highest impacts were found for the climate scenario RCP 8.5 for the long-term period and the lowest for RCP 4.5 for the short-term period. The results from this modeling approach can be used for planning purposes in a floodplain management study. The modeling approach identifies critical areas that need to be protected to mitigate future flood risks. Higher resolution climate change and field data are needed to obtain detailed results required for a final design that will mitigate these risks.

Evaluation of the Effect of Hamao Detention Pond on Excess Runoff from the Abukuma River in 2019 and Simple Remodeling of the Pond to Increase Its Flood Control Function

Due to the recent increase in the intensity of rainstorms, the Japanese government has announced a new policy of flexible flood mitigation measures that presupposes the release of water volumes exceeding the river channel capacity onto floodplains. However, due to the limited amount of quantitative measurement data on excess runoff, it will take time to formulate planning standards for remodeling and newly constructing flood control facilities reasonable enough under current budgetary constraints. In this study, the capacity shortage of a flood detention pond was evaluated against the excess runoff from a severe 2019 flood event by combining the fragmentary measurement data with a numerical flow simulation. Although the numerical model was a rather simple one commonly used for rough estimation of inundation areas in Japan, the results were overall consistent with the observations. Next, in accordance with the new policy, an inexpensive remodeling of the detention basin, which was designed according to conventional standards, was simulated; the upstream side of the surrounding embankment was removed so that excess water flowed up onto the floodplain gradually. Numerical experiments using the simple model indicated that the proposed remodeling increased the effectiveness of flood control remarkably, even for floods greater than the 2019 flood, without much inundation damage to upstream villages.

Assessment of flood susceptibility mapping using support vector machine, logistic regression and their ensemble techniques in the Belt and Road region

Floods have occurred frequently all over the world. During 2000–2020, nearly half (44.9%) of global floods occurred in the Belt and Road region because of its complex geology, topography, and climate. Therefore, providing an insight into the spatial distribution characteristics of flood susceptibility in this region is essential. Here, a database was established with 11 flood conditioning factors, 1500 flooded points, and 1500 non-flooded points selected by an improved method. Subsequently, a rare combination of logistic regression and support vector machine, integrated by heterogeneous framework, was applied to generate an ensemble flood susceptibility map. Based on it, the concept of ecological vulnerability synthesis index in the ecological field was introduced into this study, and the flood susceptibility comprehensive index (FSCI) was proposed to quantify the degree of flood susceptibility of each country and sub-region. At the results, the ensemble model has an excellent accuracy, with the highest AUC value of 0.9342. The highest and high flood susceptibility zones are mainly located in the southeastern part of Eastern Asia, most of Southeast Asia and South Asia, account for 12.22% and 9.57% of the total study area, respectively. From the regional perspective, it can be found that Southeast Asia had the highest flood susceptibility with the highest FSCI of 4.69, while East Asia and Central and Eastern Europe showed the most significant spatial distribution characteristics. From the national perspective, of the 66 countries in this region, 20 of the countries have the highest flood susceptibility level (FSCIn > 0.8), which face the greatest threat of flooding. These results are able to facilitate reasonable flood mitigation measures develop at the most critical locations in the Belt and Road region and lays a theoretical basis for quantifying flood susceptibility at national or regional scale.

Comprehensive Assessment of Flood Hazard, Vulnerability, and Flood Risk at the Household Level in a Municipality Area: A Case Study of Nan Province, Thailand

Estimating flood hazard, vulnerability, and flood risk at the household level in the past did not fully consider all relevant parameters. The main objective of this study is to improve this drawback by developing a new comprehensive and systematic methodology considering all relevant parameters and their weighting factors. This new methodology is applied to a case study of flood inundation in a municipal area of Nan City in the Upper Nan River Basin in Thailand. Field and questionnaire surveys were carried out to collect pertinent data for input into the new methodology for estimating flood hazard, vulnerability, and risk. Designed floods for various return periods were predicted using flood simulation models for assessing flood risk. The flood risk maps constructed for the return periods of 10–500 years show a substantial increase in flood risk with the return periods. The results are consistent with past flood damages, which were significant near and along the riverbanks where ground elevation is low, population density is high, and the number of household properties are high. In conclusion, this new comprehensive methodology yielded realistic results and can be used further to assess the effectiveness of various proposed flood mitigation measures.

Flood mitigation data analytics and decision support framework: Iowa Middle Cedar Watershed case study

Flooding is one of the most frequent natural disasters, causing billions of dollars in damage and threatening vulnerable communities worldwide. Although the impact of flooding can never be diminished, minimizing future losses is possible by taking structural or non-structural mitigation actions. Mitigation applications are often costly practices. However, they can be more feasible for long-term planning and protection. On the other hand, selecting a feasible option requires a comprehensive analysis of potential risk and damages and comparing the costs and benefits of different mitigation types. This paper presents a web-based decision support framework called Mitigation and Damage Assessment System (MiDAS) that analyzes flood risk impacts and mitigation strategies at the community and property-level with the goal of informing communities on the consequences of flooding and mitigation alternatives and encouraging them to participate in the community rating system. The framework utilizes regulatory flood inundation maps, damage functions, property information, scenario-based climate projections, and mitigation inputs and guidelines from the Federal Emergency Management Agency (FEMA) and the United States Army Corps of Engineers (USACE). It will help users select the appropriate flood mitigation measures based on various characteristics (e.g., foundation type, occupancy, square footage) and provide cost estimates for implementing measures. The system also provides a decision tree algorithm for analyzing and representing the mitigation decision by reviewing existing guidelines (e.g., FEMA, USACE). We analyzed the community-level mitigation for three major cities in Eastern Iowa (Cedar Falls, Cedar Rapids, and Waterloo) and found certain measures (e.g., wet/dry floodproofing) are cost-effective for community-level mitigation. Implementation of mitigation measures can reduce the property's vulnerability and improve the response to a flooding event.

Prirodi bliska rešenja kao održive mere za smanjenje hidrometeoroloških rizika - primer sliva reke Tamnave

This paper presents briefly a holistic approach to reducing flood risks using the nature-based solutions. This approach takes into account not only the reduced risk as the primary goal of flood mitigation, but also involves other goals such as the protection of the environment, human well-being, socio-economic goals etc. The Tamnava River basin is used as a pilot case to demonstrate the methodology of such an approach, resulting from the work within the RECONECT project from the EU Horizon 2020 programme. The paper presents preliminary results for the Tamnava River basin by considering several scenarios for flood mitigation measures and potential benefits from these measures in flood risk reduction and in improved ecosystem services in the basin. The methodology includes monetary valuation of the effects of the proposed flood mitigation measures in terms of the avoided damages, as well as of the secondary benefits from the erosion control by additional afforestation. The latter also provides basis for preliminary valuation of all relevant ecosystem services in the basin, thus indicating the value of the basin's natural capital. Such an evaluation is important for the decision-making process on possible flood mitigation strategies.

Geomorphological Spatial Model of Risk Analysis for Natural Disasters in Heritage Railway Tunnel

Flood event in Ijo Tunnel led to disruption to schedules and train routes. The objectives of this research are to determine the susceptibility, vulnerability, capacity, and risk, to analyze the geophysical and geotechnical condition, and to compile the strategy of disaster mitigation of Ijo Tunnel. A spatial approach based on landform analysis was performed to establish the disaster components. Geophysical and geotechnical investigation was conducted to describe the condition of the affected region. A field survey was accomplished to collect data and to study supporting works of literature. The descriptive analysis was completed to determine strategy and recommendation in flood and potential landslide mitigation. The result depicts that Ijo Tunnel holds multi-disaster risk such as floods and landslides. The occurrence of floods is induced by extreme rainfall and inability of drainage channels to retain water. The landslide potential is influenced by morphological factors and composting materials in Ijo Tunnel’s region. The existence of spring fracture on the north slope also contributes to increasing the slopes’ landslide potential. The flood mitigation measure can be carried out by building a well-prepared drainage system and watershed and surface runoff management. Areas with a high level of landslide susceptibility can be overcome by building permanent retaining walls and pipes on slopes to reduce the soil saturation level.

Using Social Networks Analysis to Inform Political Feasibility: The Case of Flood Mitigation Measures in Quebec

Using Social Networks Analysis to Inform Political Feasibility: The Case of Flood Mitigation Measures in Quebec

Flood Mapping in Valley Districts of Manipur Using Satellite-based Synthetic Aperture Radar (SAR) Images

Impacts from flood pose high risk to lives and properties of river plain inhabitants across the globe. Plains of Northeast India, including central valley in Manipur, often experience floods of variable intensities in different seasons of the year. Current flood mitigation measures of the region scarcely consider the dissimilarity in inundation patterns produced by floods of different seasons. Considering this, the current study examined the inundation pattern of pre-monsoon and monsoon floods in five valley districts of Manipur using Synthetic Aperture Radar (SAR) data of Sentinel-1 satellite. SAR images of April (premonsoon) and July (monsoon), and a pre-flood image (March) of the year 2017 were employed for the analysis. The results indicate that the extent of inundation during monsoon flood (20222 ha) was about four times larger than the pre-monsoon flood (4297 ha). Imphal West and Thoubal districts witnessed largest area under inundation during pre-monsoon and monsoon flood respectively. And moving from premonsoon to monsoon, Kaching, Thoubal Imphal East, and Bisnupur experienced the largest percentage climb in inundation area while it only changed slightly in Imphal West. This suggest that spatial pattern of flooding exhibited significant variations among the districts between the floods. Therefore, to be more effective in future, flood management strategies need inputs from flood mapping studies performed using space-based SAR data.

Multicriteria analysis for identification of flood control mechanisms: Application to extreme events in cities of different Brazilian regions

The alteration of the land use of watersheds by urbanization generates changes in the hydrological response of a region. Urbanization brings improvements to the population's quality of life; however, the increase in impermeable surfaces, often without proper planning, has an impact on the environment. Impermeable surfaces decrease the infiltration of water and increase the runoff volume. Floods are common problems in cities with urban planning failures or accelerated population growth. In recent decades, municipalities have sought to invest in low-environmental-impact tools that control stormwater, such as best management practices (BMPs) and low-impact development (LID). To implement these tools, it is necessary to analyze the characteristics of each city, with the aim of selecting the best solution for flood control for that city. In this study, the main criteria considered in the decision-making process for the implementation of low-environmental-impact structural flood mitigation measures were identified as Control Mechanisms (CMs). Fuzzy logic was applied to five Brazilian cities with flood records to identify the most appropriate CMs for each city, based on the criteria analyzed. For the cities considered, the most adequate flood control mechanism, according to the criteria, was found to be the detention basin, with a minimum effectiveness of 0.892.

Development of a Hydrodynamic-Based Flood-Risk Management Tool for Assessing Redistribution of Expected Annual Damages in a Floodplain

Despite spending ample resources and procedural development in flood management, flood losses are still increasing worldwide. The losses caused by floods and costs incurred on management are two components of expected annual damages (EAD) due to floods. This study introduces a generalized approach for risk-based design where a range of probable floods are considered before and after a flood mitigation measure is implemented. The proposed approach is customized from the ISO Guide 31000 along with additional advantages of flood risk visualization. A Geographic Information System (GIS)-based design of a flood-protection dike is performed to exhibit the risk redistribution. The Chenab River is selected for the existing dike system. Detailed hazard behaviour and societal vulnerability are modelled and visualized for a range of all probable floods before and after the implementation of flood-protection dikes. EAD maps demonstrate the redistribution of induced and residual risks. It can be concluded that GIS-based EAD maps not only facilitate cost-effective solutions but also provide an accurate estimate of residual risks after the mitigation measures are applied. EAD maps also indicate the high-risk areas to facilitate designing secondary measures.

Street Level Flood Monitoring and Warning System, a conceptual model using IoT: A Case of Surat City

Most of the natural disasters are unpredictable, but the most frequent occurring catastrophic event over the globe is flood. Developing countries are severely affected by the floods because of the high frequencies of floods. The developing countries do not have good forecasting system compared to the developed country. The metro cities are also settled near the coast or river bank which are the most vulnerable places to floods. This study proposes plan for street level flood monitoring and warning system for the Surat city, India. Waterlogging happens in the low lying area of the Surat city due to heavy storm and heavy releases from the Ukai dam. The high releases from upstream Ukai dam and heavy rainfall resulted into flooding in the low lying area of the Surat city. This research proposed a wireless water level sensor network system for the street water level flood monitoring. The system is proposed to monitor the water levels of different areas of city through the wireless water level sensors as well as to capture live photos using CCTV camera. This will help authority not only to issue flood warning but also to plan flood mitigation measures and evacuation of people.

Dam break analysis using HEC-RAS and HEC-GeoRAS: A case study of Hidkal dam, Karnataka state, India

A dam is a structure constructed across river which stores water and supplies water for various purposes. Though the dams have many benefits, there is always a threat of dam break floods which are devastating in nature. Hence it becomes essential to analyze and simulate dam failure scenarios to understand the severity of dam break flood and identify areas under threat which helps in land use planning and developing emergency response plans. This study attempts to carry out dam break/breach analysis for the Hidkal dam using a one-dimensional hydraulic model called Hydraulic Engineering Center's River Analysis System (HEC-RAS). HEC-GeoRAS tool is used to extract river geometry data from the Cartosat-1 digital elevation model (DEM) and to generate the inundation map to identify the areas affected. The study involves the prediction of breach parameters, breach flood hydrograph, peak flow, flood arrival time, and generation of inundation maps. The dam break model is simulated for unsteady flow conditions using Probable Maximum Flood (PMF) corresponding to piping and overtopping failure scenarios. HEC-RAS tool is utilized to determine the breach outflow hydrograph and hydraulic conditions at critical downstream locations. Further, the breach outflow hydrographs are routed using dynamic flood wave routing. Further HEC-RAS model is simulated for breach parameters derived from five different empirical methods, and the results are compared. A sensitivity analysis is also carried out to know the variation of peak flow and maximum stage with respect to the breach parameters. The immediate downstream of the dam experience a peak flow of 72,085.45 m3/s and 78,454.82 m3/s and the corresponding inundation area of 75.224 km2 and 79.205 km2 due to piping failure and overtopping failure, respectively. Around twenty village located on the downstream of dam location gets affected due to flood produced by dam break. The analysis shows that overtopping failure is more severe than failure due to piping. The study shall further help authorities concerned to develop an emergency response plan and flood mitigation measures.