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1
Lee, Jin-Young, Ho-Jun Son, Dongwook Kim, Jae-Hee Ryu, and Tae-Woong Kim. "Evaluating the Hydrologic Risk of n-Year Floods According to RCP Scenarios." Water 13, no. 13 (June 29, 2021): 1805. http://dx.doi.org/10.3390/w13131805.
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Recent climate change has brought about irregular rainfall patterns along with an increased frequency of heavy rainfall, and flood damage in Korea is increasing accordingly. The increased rainfall amount and intensity during the rainy season lead to flood damage on a massive scale every year in Korea. In order to reduce such flood damage and secure the stability of hydraulic structures, evaluation of hydrologic risk corresponding to design floods is necessary. As Korea’s current climate change scenarios are generally applied to mid-sized watersheds, there is no practical application method to calculate the hydrologic risk of local floods corresponding to various future climate change scenarios. Using the design flood prediction model, this study evaluated the hydrologic risks of n-year floods according to 13 climate change scenarios. The representative concentration pathway (RCP) 8.5 scenario resulted in the 100-year floods increasing 134.56% on average, and 132.30% in the Han River, 132.81% in the Nakdong River, 142.42% in the Gum River, and 135.47% in the Seomjin-Youngsan River basin, compared with the RCP 4.5. The 100-year floods at the end of the 21st century increased by +3% and +13% according to the RCP 4.5 and 8.5, respectively. The corresponding hydrologic flood risk increased by 0.53% and 8.68% on average according to the RCP 4.5 and RCP 8.5, respectively, compared with the current level of hydrologic risk of a 100-year flood.
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Lohani, A. K., Gopal Krishan, and Surendra Chandniha. "Hydrological Disasters Management and Risk Assessment." Current World Environment 12, no. 3 (December 24, 2017): 520–29. http://dx.doi.org/10.12944/cwe.12.3.05.
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In India, floods and droughts are recurrent hydrological phenomenon causing huge losses to lives, livelihood, properties and infrastructure due to non-uniformly distributed rainfall both in time and space leading to the dimensionally opposite problems of flood and drought in different parts of the country. Out of 3290 lakh hectares geographical area, 40 million hectares is prone to floods which show high risk, vulnerability and is one of the most common hydrologic extremes frequently experienced by our country. On the other hand drought has a varying frequency from once in two years to once in fifteen years. It has been observed that there is flood in one part of country and severe drought in the other part. Various short term and long term measures should be adopted to prevent and mitigate the consequences of floods and drought rather than causing damages and losses due to interfering of the natural processes. In this paper, drought and flood problems in India are highlighted along with some of the important management issues requiring immediate attention. Furthermore, it presents the recently developed non-structural techniques for flood forecasting, flood plain zoning, glacial lake outburst modeling and decision support system.
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Zhang, Qi, Wei Jian, and Edmond Yat Man Lo. "Assessment of Flood Risk Exposure for the Foshan-Zhongshan Region in Guangdong Province, China." Water 12, no. 4 (April 18, 2020): 1159. http://dx.doi.org/10.3390/w12041159.
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Floods have caused 20% of the worldwide economic losses resulting from catastrophe events over 2008 to 2018. In China, the annual flood economic losses have exceeded CNY 100 billion from 1990 to 2010, which is equivalent to 1% to 3% of China’s Gross Domestic Product (GDP). This paper presents a rainfall-runoff model coupled with an inundation estimation to assess the flood risk for a basin within the Foshan-Zhongshan area of the Pearl River Delta (PRD) region in China. A Hydrologic Engineering Center’s Hydrologic Modeling System (HEC-HMS) model was constructed for the crisscrossing river network in the study basin where the West and North Rivers meet, using publicly accessible meteorological, hydrological and topographical datasets. The developed model was used to analyze two recent flood events, that in July 2017 with large upstream river inflows, and in June 2018 with high local rainfall. Results were further used to develop the needed river rating curves within the basin. Two synthetic events that consider more severe meteorological and hydrological conditions were also analyzed. These results demonstrate the capability of the proposed model for quick assessment of potential flood inundation and the GDP exposure at risk within the economically important PRD region.
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Latif, Shahid, and Firuza Mustafa. "Bivariate Hydrologic Risk Assessment of Flood Episodes using the Notation of Failure Probability." Civil Engineering Journal 6, no. 10 (October 1, 2020): 2002–23. http://dx.doi.org/10.28991/cej-2020-03091599.
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Floods are becoming the most severe and challenging hydrologic issue at the Kelantan River basin in Malaysia. Flood episodes are usually thoroughly characterized by flood peak discharge flow, volume and duration series. This study incorporated the copula-based methodology in deriving the joint distribution analysis of the annual flood characteristics and the failure probability for assessing the bivariate hydrologic risk. Both the Archimedean and Gaussian copula family were introduced and tested as possible candidate functions. The copula dependence parameters are estimated using the method-of-moment estimation procedure. The Gaussian copula was recognized as the best-fitted distribution for capturing the dependence structure of the flood peak-volume and peak-duration pairs based on goodness-of-fit test statistics and was further employed to derive the joint return periods. The bivariate hydrologic risks of flood peak flow and volume pair, and flood peak flow and duration pair in different return periods (i.e., 5, 10, 20, 50 and 100 years) were estimated and revealed that the risk statistics incrementally increase in the service lifetime and, at the same instant, incrementally decrease in return periods. In addition, we found that ignoring the mutual dependency can underestimate the failure probabilities where the univariate events produced a lower failure probability than the bivariate events. Similarly, the variations in bivariate hydrologic risk with the changes of flood peak in the different synthetic flood volume and duration series (i.e., 5, 10, 20, 50 and 100 years return periods) under different service lifetimes are demonstrated. Investigation revealed that the value of bivariate hydrologic risk statistics incrementally increases over the project lifetime (i.e., 30, 50, and 100 years) service time, and at the same time, it incrementally decreases in the return period of flood volume and duration. Overall, this study could provide a basis for making an appropriate flood defence plan and long-lasting infrastructure designs. Doi: 10.28991/cej-2020-03091599 Full Text: PDF
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Jha, Manoj, and Sayma Afreen. "Flooding Urban Landscapes: Analysis Using Combined Hydrodynamic and Hydrologic Modeling Approaches." Water 12, no. 7 (July 14, 2020): 1986. http://dx.doi.org/10.3390/w12071986.
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The frequency and severity of floods have been found to increase in recent decades, which have adverse effects on the environment, economics, and human lives. The catastrophe of such floods can be confronted with the advance prediction of floods and reliable analyses methods. This study developed a combined flood modeling system for the prediction of floods, and analysis of associated vulnerabilities on urban infrastructures. The application of the method was tested on the Blue River urban watershed in Missouri, USA, a watershed of historical significance for flood impacts and abundance of data availability for such analyses. The combined modeling system included two models: hydrodynamic model HEC-RAS (Hydrologic Engineering Center—River Analysis System) and hydrologic model SWAT (Soil and Water Assessment Tool). The SWAT model was developed for the watershed to predict time-series hydrograph data at desired locations, followed by the setup of HEC-RAS model for the analysis and prediction of flood extent. Both models were calibrated and validated independently using the observed data. The well-calibrated modeling setup was used to assess the extent of impacts of the hazard by identifying the flood risk zones and threatened critical infrastructures in flood zones through inundation mapping. Results demonstrate the usefulness of such combined modeling systems to predict the extent of flood inundation and thus support analyses of management strategies to deal with the risks associated with critical infrastructures in an urban setting. This approach will ultimately help with the integration of flood risk assessment information in the urban planning process.
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Gabriel, Rosemary Kiama, and Yurui Fan. "Multivariate Hydrologic Risk Analysis for River Thames." Water 14, no. 3 (January 27, 2022): 384. http://dx.doi.org/10.3390/w14030384.
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This study analyzed the multivariate flood risk for the river Thames at Kingston based on historical flood data from the National River Flow Archive (NRFA) website. The bivariate risk analysis framework was prepared from the joint return periods of the peak flow (m3/s) and 3-day annual maximum flow (m3/s) flood pair. A total of 137 samples of flood pairs from 1883 to 2019 were adopted for risk analysis. The multivariate return periods were characterized depending on the quantification of the bivariate flood frequency analysis of the pair through copulas methods. The unknown parameter of each copula was estimated using the method-of-moment (MOM) estimator based on Kendall’s tau inversion, in which the Clayton copula performed best to model the dependence of the two flood variables. Then, the bivariate hydrologic risk was characterized based on the joint return period in AND, established from the Clayton copula method. The results reveal that the flood pair would keep a constant hydrologic risk value for some time then moderately decrease as the 3-day AMAX flow increases from 700 m3/s. This hydrologic risk indicator was analyzed under four service time scenarios and three peak flows whose return periods were positioned at 50, 100, and 150 years. The outcomes from the bivariate risk analysis of the flood pairs can be used as decision support during the design of flood defenses and hydraulic facilities.
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Harkat, N., S. Chaouche, and M. Bencherif. "Flood Hazard Spatialization Applied to The City of Batna: A Methodological Approach." Engineering, Technology & Applied Science Research 10, no. 3 (June 7, 2020): 5748–58. http://dx.doi.org/10.48084/etasr.3429.
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Flood flows can cause destruction to properties and infrastructure or even cost human lives. Batna is an Algerian city that is highly exposed to the risk of flooding, with an average of one flood every three to four years. The current methods utilized to analyze flood hazards are limited to the hydrology of the watershed. Limiting the analysis of flood hazards could mislead the decision-makers from proper management of such risks. The objective of the current study is to propose a simplified flood hazard model called HEC RAS-DTM (Hydrologic Engineering Centers River Analysis System (HEC RAS)-Digital Terrain Model (DTM)) and to evaluate it utilizing data gathered from the hydrological context and the hydraulic modeling of Batna city. The model entails two distinct phases. Initially, it attempts to use descriptive statistical methods based mainly on frequency analysis, which consists of studying flood flows in order to determine the probability of future flood occurrence. The analysis of the hydrological context of the city of Batna has revealed that peak flows from stream floods have been predicted at various return periods. Subsequently, HEC RAS was deployed to produce hydraulic modeling in order to extract the water heights and speeds corresponding to these expected flows. These data, along with DTM, are crucial for the spatialization of flood hazards. The hydraulic modeling and simulation using HEC-RAS and Geographic Information System (ArcGIS) of water flow at the two main valleys, Oued Batna and Oued El Gourzi, allowed predicting the extent of flooding that could occupy a large part of the city. The mapping of the flood hazard revealed the sectors that would be most exposed. The results obtained from the suggested model confirm that a significant portion of the city of Batna remains vulnerable to floods in relevance with the predicted flood return periods. The suggested model has indicated significant growth in flood locality. Additionally, the model was proved to be efficient for the analysis of flood flows, and it could easily substitute conventional analysis methods. Further studies or investigations are advised in order to replicate the study in different contexts. The article entails suggestions for properly managing flood risks. Future studies on flood risk alleviation in Batna city could be likewise considered.
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Chai, Fu Xin, Dong Mei Chai, Hui Ran Dai, and Shi Feng Huang. "3D-GIS System Research and Development for Emergency Hydrologic Analysis." Applied Mechanics and Materials 641-642 (September 2014): 3–8. http://dx.doi.org/10.4028/www.scientific.net/amm.641-642.3.
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In view of the present situation of frequent flood and drought disaster in China, and lacking of technology for emergency hydrologic monitoring system and emergency response analysis. Face to emergency hydrologic forecast, this paper study on hydrologic information extraction and flood inundation risk emergency, and set up emergency hydrologic analysis system with the function of emergency hydrologic information extraction, flood simulation, flood analysis and hazard evaluation and so on. The system provided technical support and analysis platform for emergency hydrologic monitoring, forecasting and decision making.
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Ghaith, Maysara, Ahmed Yosri, and Wael El-Dakhakhni. "Synchronization-Enhanced Deep Learning Early Flood Risk Predictions: The Core of Data-Driven City Digital Twins for Climate Resilience Planning." Water 14, no. 22 (November 10, 2022): 3619. http://dx.doi.org/10.3390/w14223619.
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Floods have been among the costliest hydrometeorological hazards across the globe for decades, and are expected to become even more frequent and cause larger devastating impacts in cities due to climate change. Digital twin technologies can provide decisionmakers with effective tools to rapidly evaluate city resilience under projected floods. However, the development of city digital twins for flood predictions is challenging due to the time-consuming, uncertain processes of developing, calibrating, and coupling physics-based hydrologic and hydraulic models. In this study, a flood prediction methodology (FPM) that integrates synchronization analysis and deep-learning is developed to directly simulate the complex relationships between rainfall and flood characteristics, bypassing the computationally expensive hydrologic-hydraulic models, with the City of Calgary being used for demonstration. The developed FPM presents the core of data-driven digital twins that, with real-time sensor data, can rapidly provide early warnings before flood realization, as well as information about vulnerable areas—enabling city resilience planning considering different climate change scenarios.
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Udom, Nuon, Istiarto Istiarto, and Adam Pamudji Rahardjo. "Evaluation of Flood Risk Reduction Project at Tenggang River, Semarang City, Central Java Province, Indonesia." Journal of the Civil Engineering Forum 4, no. 2 (May 13, 2018): 159. http://dx.doi.org/10.22146/jcef.34035.
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Evaluation of flood risk reduction at Tenggang River is needed to reduce the urban and coastal flood from high-intensity rainfall and sea level rise. This paper mainly discusses rainfall frequency analysis, simulation of hydraulic structure performed by HEC-RAS 5.0.3, and the proposed alternative flood mitigation for 25-year flood return period. Hydrology and hydraulic was analyzed to investigate the flooding risk. The result of simulation illustrated the improvement channel condition by normalization the riverbed and the increase of levee to solve flood inundation at Tenggang River using the designated flood return period (25 years of return period, Q25 = 119 m3/s). The result of simulation showed that the hydrologic-hydraulic modeling is acceptable compared to the report from the office of public work in Semarang City.
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Abendaño, Marie Angelie C., Joan M. Recente, and Jennifer P. Barroso. "Hydrologic Model for Flooding in Manupali Watershed and Its Implications to Land-Use Policies." Asia Pacific Journal of Social and Behavioral Sciences 18 (January 8, 2021): 121–35. http://dx.doi.org/10.57200/apjsbs.v18i0.236.
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Flooding has become a recurring event in the Province of Bukidnon, causing severe destruction to houses, buildings, infrastructure, and livelihood. Since the province is not exempted in flooding events as an impact of typhoons, understanding the watershed hydrologic behavior is essential for vulnerability and risk assessment as to disaster preparedness and risk reduction. The study aims to analyze the hydrologic response of Manupali watershed through flood hazard maps, hydrologic, and hydraulic models. This paper presents the combination of geographic information system, high -resolution digital elevation model (DEM), land cover, observed hydro-meteorological data, and the combined hydrologic engineering center-hydrologic modeling system and river analysis system models. The hydrologic model assesses the relationship between rainfall and discharge of the watershed and the hydraulic model computes the flood depth and flow pattern in the floodplain. Upon calibration, the over-all performance of the hydrologic model was rated very good in its performance based on the standards set by Moriasi et al. (2015) with index values of 0.89, 0.75, 0.46. The calibrated hydrographs were used to produce flood hazard maps in 2, 5, 10, 25, 50, and 100-year return periods, and assessed the number of flooded buildings in each flood hazard level per return period. The flood hazard maps may contribute to science-based land-use policy formulation, land-use zoning, planning, and management to mitigate extreme rainfall-induced flood risks in the affected barangays in the Manupali watershed.
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Sari, Prorida, Djoko Legono, and Joko Sujono. "Performance of Retarding Basin in Flood Disaster Risk Mitigation in Welang River, East Java Province, Indonesia." Journal of the Civil Engineering Forum 4, no. 2 (May 13, 2018): 109. http://dx.doi.org/10.22146/jcef.31938.
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Flood phenomenon caused by high rainfall and sea tides on a watershed seat the tidal area, including the Welang River, commonly occur and the number of events is increasing. Construction of retarding basin is one of flood risk mitigation efforts by reducing the flood peak discharge. Assessment of flood management in Welang River was conducted with hydrology and hydraulic approaches, by using the Hydrologic Engineering Centre-Hydrologic Modelling System (HEC-HMS) 4.0 and Hydrologic Engineering Center–River Analysis System (HEC-RAS) 5.0.3 software. The hydraulic simulation consists of 4 scenarios. Scenario 1 was the current condition, while scenario 2, 3, and 4 were the retarding basin construction with one side spillway, one on the upstream (River Station (RS) 7400), on the middle (RS 6970), and on the downstream (RS 6590), respectively. The height variation of side spillways are 3 m and 4 m. Flood routing simulation result showed that the existing river channel condition could not accommodate of 2-year flood and 10-year flood, which caused peak discharge of 497.7 m3/s and 794.9 m3/s. At the RS 6590, the maximum runoff height of 2-year and 10-year flood were 0.66 and 1.02 m, respectively. Under the 2-year return period of flood, the discharge reduction caused by the retarding basin at control point RS 5341.4 (Karangketug Village), were 39.63 m3/s, 31.83 m3/s, and 41.93 m3/s, respectively for scenario 2, 3 and 4 with the 3 m side spillway height and 14.71 m3/s, 16.76 m3/s, and 13.74 m3/s, respectively for scenario 2, 3 and 4 with the 4 m side spillway height.
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Beltaos, Spyros. "Assessing the Frequency of Floods in Ice-Covered Rivers under a Changing Climate: Review of Methodology." Geosciences 11, no. 12 (December 14, 2021): 514. http://dx.doi.org/10.3390/geosciences11120514.
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Ice-influenced hydrologic and hydrodynamic processes often cause floods in cold regions of the globe. These floods are typically associated with ice jams and can have negative socio-economic impacts, while their impacts on riverine ecosystems can be both detrimental and beneficial. Several methods have been proposed for constructing frequency distributions of ice-influenced annual peak stages where historical data are scarce, or for estimating future frequencies under different climate change scenarios. Such methods rely on historical discharge data, which are generally easier to obtain than peak stages. Future discharges can be simulated via hydrological models, driven by climate-model output. Binary sequences of historical flood/no-flood occurrences have been studied using logistic regression on physics-based explanatory variables or exclusively weather-controlled proxies, bypassing the hydrological modelling step in climate change projections. Herein, background material on relevant river ice processes is presented first, followed by descriptions of various proposed methods to quantify flood risk and assess their advantages and disadvantages. Discharge-based methods are more rigorous; however, projections of future flood risk can benefit from improved hydrological simulations of winter and spring discharges. The more convenient proxy-based regressions may not adequately reflect the controlling physics-based variables, while extrapolation of regression results to altered climatic conditions entails further uncertainty.
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Tu, Huawei, Xiekang Wang, Wanshun Zhang, Hong Peng, Qian Ke, and Xiaomin Chen. "Flash Flood Early Warning Coupled with Hydrological Simulation and the Rising Rate of the Flood Stage in a Mountainous Small Watershed in Sichuan Province, China." Water 12, no. 1 (January 16, 2020): 255. http://dx.doi.org/10.3390/w12010255.
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Flash floods in mountainous areas have become more severe and frequent as a result of climate change and are a threat to public safety and social development. This study explores the application of distributed hydrological models in flash floods risk management in a small watershed in Sichuan Province, China, and aims to increase early warning lead time in mountainous areas. The Hydrologic Engineering Center’s Hydrologic Modeling System (HEC-HMS) model was used to simulate the flash flood process and analyze the variation in flood hydrographs. First, the HEC-HMS model was established based on geospatial data and the river network shape, and eight heavy rainfall events from 2010 to 2015 were used for model calibration and validation, showing that the HEC-HMS model was effective for the simulation of mountain floods in the study area. Second, with the assumption that rainfall and flood events have the same frequency, the flood hydrographs with different frequencies (p = 1%, 2%, 5%, and 10%) were calculated by the HEC-HMS model. The rising limbs of the flood hydrographs were significantly different and can be divided into three parts (0–5 h, 6–10 h, and 11–15 h). The rising rate of the flood stage for each part of the flood hydrograph increases in multiples. According to the analysis of the flood hydrographs, two critical early warning indicators with an invention patent were determined in the study: the flood stage for immediate evacuation and the rising rate. The application of the indicators in the study shows that it is feasible to advance the time of issuing an early warning signal, and it is expected that the indicators can offer a reference for flash flood early warning in the study area and other small watersheds in mountainous areas.
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Wobus, Cameron, Ethan Gutmann, Russell Jones, Matthew Rissing, Naoki Mizukami, Mark Lorie, Hardee Mahoney, Andrew W. Wood, David Mills, and Jeremy Martinich. "Climate change impacts on flood risk and asset damages within mapped 100-year floodplains of the contiguous United States." Natural Hazards and Earth System Sciences 17, no. 12 (December 8, 2017): 2199–211. http://dx.doi.org/10.5194/nhess-17-2199-2017.
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Abstract. A growing body of work suggests that the extreme weather events that drive inland flooding are likely to increase in frequency and magnitude in a warming climate, thus potentially increasing flood damages in the future. We use hydrologic projections based on the Coupled Model Intercomparison Project Phase 5 (CMIP5) to estimate changes in the frequency of modeled 1 % annual exceedance probability (1 % AEP, or 100-year) flood events at 57 116 stream reaches across the contiguous United States (CONUS). We link these flood projections to a database of assets within mapped flood hazard zones to model changes in inland flooding damages throughout the CONUS over the remainder of the 21st century. Our model generates early 21st century flood damages that reasonably approximate the range of historical observations and trajectories of future damages that vary substantially depending on the greenhouse gas (GHG) emissions pathway. The difference in modeled flood damages between higher and lower emissions pathways approaches USD 4 billion per year by 2100 (in undiscounted 2014 dollars), suggesting that aggressive GHG emissions reductions could generate significant monetary benefits over the long term in terms of reduced flood damages. Although the downscaled hydrologic data we used have been applied to flood impacts studies elsewhere, this research expands on earlier work to quantify changes in flood risk by linking future flood exposure to assets and damages on a national scale. Our approach relies on a series of simplifications that could ultimately affect damage estimates (e.g., use of statistical downscaling, reliance on a nationwide hydrologic model, and linking damage estimates only to 1 % AEP floods). Although future work is needed to test the sensitivity of our results to these methodological choices, our results indicate that monetary damages from inland flooding could be significantly reduced through substantial GHG mitigation.
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Manfreda, Salvatore, Caterina Samela, Alberto Refice, Valerio Tramutoli, and Fernando Nardi. "Advances in Large-Scale Flood Monitoring and Detection." Hydrology 5, no. 3 (September 3, 2018): 49. http://dx.doi.org/10.3390/hydrology5030049.
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The last decades have seen a massive advance in technologies for Earth observation (EO) and environmental monitoring, which provided scientists and engineers with valuable spatial information for studying hydrologic processes. At the same time, the power of computers and newly developed algorithms have grown sharply. Such advances have extended the range of possibilities for hydrologists, who are trying to exploit these potentials the most, updating and re-inventing the way hydrologic and hydraulic analyses are carried out. A variety of research fields have progressed significantly, ranging from the evaluation of water features, to the classification of land-cover, the identification of river morphology, and the monitoring of extreme flood events. The description of flood processes may particularly benefit from the integrated use of recent algorithms and monitoring techniques. In fact, flood exposure and risk over large areas and in scarce data environments have always been challenging topics due to the limited information available on river basin hydrology, basin morphology, land cover, and the resulting model uncertainty. The ability of new tools to carry out intensive analyses over huge datasets allows us to produce flood studies over large extents and with a growing level of detail. The present Special Issue aims to describe the state-of-the-art on flood assessment, monitoring, and management using new algorithms, new measurement systems and EO data. More specifically, we collected a number of contributions dealing with: (1) the impact of climate change on floods; (2) real time flood forecasting systems; (3) applications of EO data for hazard, vulnerability, risk mapping, and post-disaster recovery phase; and (4) development of tools and platforms for assessment and validation of hazard/risk models.
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Sufiyan, Ibrahim, Magaji J.I, and A. T. Ogah. "HYDROLOGIC ASSESSMENT OF FOOD USING SWAT AS GEOSPATIAL TECHNIQUES IN THE CATCHMENT AREA OF TERENGGANU MALAYSIA." Malaysian Journal of Geosciences 4, no. 2 (August 13, 2020): 90–95. http://dx.doi.org/10.26480/mjg.02.2020.90.95.
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Risks and hazards are two important issues currently threatening humanity and the environment. Flood has claimed many lives and destroyed properties in Malaysia and Africa and Nigeria. It is global catastrophe. The application of geospatial science is, therefore, very important advantages that it offers solutions to flood. This stud uses of Advanced Space-borne Thermal Emission and Reflection Radiometer Digital Elevation Model (ASTER-DEM), and the Soil Water Assessment Tool (SWAT) in visualizing floods disaster risk. The whole catchment area of Terengganu has been delineated. The 25 sub-basins have been identified and the flood risk zones have been modeled. The complete watersheds are characterized by different sub-basins and Hydrologic Respond Units (HRUs) which can be viewed in 3D environment.
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Meresa, Hadush, Bernhard Tischbein, and Tewodros Mekonnen. "Climate change impact on extreme precipitation and peak flood magnitude and frequency: observations from CMIP6 and hydrological models." Natural Hazards 111, no. 3 (January 24, 2022): 2649–79. http://dx.doi.org/10.1007/s11069-021-05152-3.
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AbstractChanges in climate intensity and frequency, including extreme events, heavy and intense rainfall, have the greatest impact on water resource management and flood risk management. Significant changes in air temperature, precipitation, and humidity are expected in future due to climate change. The influence of climate change on flood hazards is subject to considerable uncertainty that comes from the climate model discrepancies, climate bias correction methods, flood frequency distribution, and hydrological model parameters. These factors play a crucial role in flood risk planning and extreme event management. With the advent of the Coupled Model Inter-comparison Project Phase 6, flood managers and water resource planners are interested to know how changes in catchment flood risk are expected to alter relative to previous assessments. We examine catchment-based projected changes in flood quantiles and extreme high flow events for Awash catchments. Conceptual hydrological models (HBV, SMART, NAM and HYMOD), three downscaling techniques (EQM, DQM, and SQF), and an ensemble of hydrological parameter sets were used to examine changes in peak flood magnitude and frequency under climate change in the mid and end of the century. The result shows that projected annual extreme precipitation and flood quantiles could increase substantially in the next several decades in the selected catchments. The associated uncertainty in future flood hazards was quantified using aggregated variance decomposition and confirms that climate change is the dominant factor in Akaki (C2) and Awash Hombole (C5) catchments, whereas in Awash Bello (C4) and Kela (C3) catchments bias correction types is dominate, and Awash Kuntura (C1) both climate models and bias correction methods are essential factors. For the peak flow quantiles, climate models and hydrologic models are two main sources of uncertainty (31% and 18%, respectively). In contrast, the role of hydrological parameters to the aggregated uncertainty of changes in peak flow hazard variable is relatively small (5%), whereas the flood frequency contribution is much higher than the hydrologic model parameters. These results provide useful knowledge for policy-relevant flood indices, water resources and flood risk control and for studies related to uncertainty associated with peak flood magnitude and frequency.
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Schwarz, Imogen, and Yuriy Kuleshov. "Flood Vulnerability Assessment and Mapping: A Case Study for Australia’s Hawkesbury-Nepean Catchment." Remote Sensing 14, no. 19 (September 30, 2022): 4894. http://dx.doi.org/10.3390/rs14194894.
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Floods are one of the most destructive natural hazards to which Australia is exposed. The frequency of extreme rainfall events and consequential floods are projected to increase into the future as a result of anthropogenic climate change. This highlights the need for more holistic risk assessments of flood affected regions. Flood risk assessments (FRAs) are used to inform decision makers and stakeholders when creating mitigation and adaptation strategies for at-risk communities. When assessing flood risk, previous FRAs from Australia’s most flood prone regions were generally focused on the flood hazard itself, and rarely considering flood vulnerability (FV). This study assessed FV in one of Australia’s most flood prone regions—the Hawkesbury-Nepean catchment, and investigated indicator-based approaches as a proxy method for Australian FV assessment instead of hydrological modelling. Four indicators were selected with the intention of representing environmental and socio-economic characteristics: elevation, degree of slope, index of relative socio-economic disadvantage (IRSD), and hydrologic soil groups (HSGs). It was found that combination of low elevation, low degree of slope, low IRSD score, and very-low infiltration soils resulted in very high levels of vulnerability. FV was shown to be at its highest in the Hawkesbury-Nepean valley flood plain region on the outskirts of Greater Western Sydney, particularly in Blacktown, Penrith, and Liverpool. This actionable risk data which resulted from the final FV index supported the practicality and serviceability of the proxy indicator-based approach. The developed methodology for FV assessment is replicable and has the potential to help inform decision makers of flood-prone communities in Australia, particularly in data scarce areas.
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Theodosopoulou, Zafeiria, Ioannis M. Kourtis, Vasilis Bellos, Konstantinos Apostolopoulos, Chryssy Potsiou, and Vassilios A. Tsihrintzis. "A Fast Data-Driven Tool for Flood Risk Assessment in Urban Areas." Hydrology 9, no. 8 (August 16, 2022): 147. http://dx.doi.org/10.3390/hydrology9080147.
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Post-disaster flood risk assessment is extremely difficult owing to the great uncertainties involved in all parts of the assessment exercise, e.g., the uncertainty of hydrologic–hydraulic models and depth–damage curves. In the present study, a robust and fast data-driven tool for residential flood risk assessment is introduced. The proposed tool can be used by scientists, practitioners and/or stakeholders as a first step for better understanding and quantifying flood risk in monetary terms. Another contribution of the present study is the fitting of an equation through depth–damage points provided by the Joint Research Center (JRC). The approach is based on hydrologic simulations for different return periods, employing a free and widely used software, HEC-HMS. Moreover, flood depths for the study area are estimated based on hydrodynamic simulations employing the HEC-RAS software and the Inverse Distance Weighting (IDW) interpolation method. Finally, flood risk, in monetary terms, is determined based on the flood depths derived by the coupling of hydrodynamic simulations and the IDW method, depth–damage curves reported in the literature, vulnerability of residential areas and the residential exposure derived by employing GIS tools. The proposed tool is applied in a highly urbanized and flood-prone area, Mandra city, in the Attica region of Greece. The results are maps of flood depths and flood risk maps for specific return periods. Overall, the results derived from the application of the proposed approach reveal that the tool can be highly effective for post-disaster flood risk management. However, it must be noted that additional information and post-disaster data are needed for the verification of the damages from floods. Additional information can result in better calibration, validation and overall performance of the proposed flood risk assessment tool.
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Papaioannou, George, Athanasios Loukas, and Lampros Vasiliades. "Flood Risk Management Methodology for Lakes and Adjacent Areas: The Lake Pamvotida Paradigm." Proceedings 7, no. 1 (November 15, 2018): 21. http://dx.doi.org/10.3390/ecws-3-05825.
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In recent decades, natural hazards have caused major disasters in natural and man-made environments. Floods are one of the most devasting natural hazards, with high levels of mortality, destruction of infrastructure, and large financial losses. This study presents a methodological approach for flood risk management at lakes and adjacent areas that is based on the implementation of the EU Floods Directive (2007/60/EC) in Greece. Contemporary engineering approaches have been used for the estimation of the inflow hydrographs. The hydraulic–hydrodynamic simulations were implemented in the following order: (a) hydrologic modeling of lake tributaries and estimation flood flow inflow to the lake, (b) flood inundation modeling of lake tributaries, (c) simulation of the lake as a closed system, (d) simulation of the lake outflows to the adjacent areas, and (e) simulation of flood inundation of rural and urban areas adjacent to the lake. The hydrologic modeling was performed using the HEC-HMS model, and the hydraulic-hydrodynamic simulations were implemented with the use of the two-dimensional HEC-RAS model. The simulations were applied to three soil moisture conditions (dry, medium and wet) and three return periods (T = 50, T = 100 and T = 1000 years) and a methodology was followed for the flood inundation modeling in urban areas. Upper and lower estimates on water depths, flow velocities and inundation areas are estimated for all inflow hydrographs and for varying roughness coefficient values. The proposed methodology presents the necessary steps and the results for the assessment of flood risk management and mapping for lake and adjacent urban and rural areas. The methodology was applied to Lake Pamvotida in Epirus, Greece, Ioannina.
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Krvavica, Nino, Ante Šiljeg, Bojana Horvat, and Lovre Panđa. "Pluvial Flash Flood Hazard and Risk Mapping in Croatia: Case Study in the Gospić Catchment." Sustainability 15, no. 2 (January 9, 2023): 1197. http://dx.doi.org/10.3390/su15021197.
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Since the beginning of the 21st Century, Europe has been affected by destructive floods. European Union Member States have an obligation to develop flood hazard and flood risk maps as support to the Flood Risk Management Plan (FRMP). The main objective of this study is to propose a methodological framework for hazard and risk assessment of pluvial flash floods in Croatia at the catchment level, which can be integrated into the FRMP. Therefore, a methodology based on the source–pathway–consequence approach for flood risk assessment is presented, which complies with the EU Floods Directive. This integrated and comprehensive methodology is based on high-resolution open data available for EU Member States. Three scenarios are defined for a low, medium, and high probability, defined by design storms of different durations. The proposed methodology consists of flood hazard analysis, vulnerability assessment, and risk analysis. Pluvial flash flood hazards are analyzed using a 2D hydrologic–hydraulic model. The flood vulnerability assessment consists of a GIS analysis to identify receptors potentially at risk of flooding and an assessment of susceptibility to potential flood damage using depth–damage curves. Flood risk is assessed both qualitatively in terms of risk levels and quantitatively in terms of direct damages expressed in monetary terms. The developed methodology was applied and tested in a case study in the Gospić catchment in Croatia, which surrounds a small rural town frequently affected by pluvial flash floods.
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Kiluva, Mary, Wanyonyi E.S, and Wakhungu J.W. "Water Balance Evaluation for Flood Risk Reduction in the Yala River Basin, Western Kenya." Journal of Climate Change and Sustainability 4, no. 1 (June 2, 2022): 13–16. http://dx.doi.org/10.20987/jccs.02.06.2022.
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The Yala River Basin (YRB) in Western region of Kenya has in the past experienced climate and weather extreme events that include floods. Floods have triggered loss of lives, destruction of property, outbreak of water borne diseases and siltation of arable land. This study utilized the Nedbør-Afstrømnings-Model (NAM) hydrologic model (available in the NAM Module of the MIKE 11 hydrodynamic model) on the Yala River Basin (YRB) to generate flood flows for water balance evaluation. The study utilized satellite imagery data for the period 1984-2010 sourced from the Regional Centre for Mapping of Resources for Development, rainfall (1980-2012) and river discharge (1947-2012) data sets from the Kenya Meteorological Department (KMD) and the Water Resources Management Authority (WARMA), respectively. Data quality control was statistically checked before sensitivity analysis, calibration, validation, and simulation of the flood flows. Daily water balance estimates for the Yala River Basin (YRB) over the period 1980-2010 were developed using the NAM hydrologic model. The results indicate that the mapped flood area extent varied by a value of 34.23 km2 over the period 1980-2010. The Yala River Basin (YRB) indicated an estimated inflow value of 4,814.72 MCM and outflow value of 4,578.23 MCM, with a coefficient of determination of 0.867. The difference between the inflow and outflow values was 236.49 MCM, that formed the flood flow or the water balance. This study concluded that the water balance value of 236.49 MCM was responsible for the floods recorded in the Yala River Basin (YRB) for the period 1980-2010, and it should be taken care of through flood risk reduction initiatives.
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Baecher, Gregory B., and Gerald E. Galloway. "US Flood risk management in changing times." Water Policy 23, S1 (December 1, 2021): 202–15. http://dx.doi.org/10.2166/wp.2021.269.
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Abstract The traditional regulatory and policy approach to flood risk in the US has been the optimization of benefits and costs, broadly mandated by federal policy. However, optimization may not be the best approach to flood risk management in light of the deep uncertainties we now face. A more incremental approach using a satisficing strategy may be. Flood risk is a function of the hydrologic factors that produce a hazard and the consequences of the hazard interfacing with the people and property exposed. Regretfully, both hydrologists and climatologists seem unable to provide the clairvoyant guidance needed by the water community facing major decisions on flood risk management in the coming years. As the seminal ‘Red Book’ noted, two things have become second nature to policy analysts and risk managers: absolute safety is unachievable, and it is necessary to distinguish between science and policy. The forcing elements and largest unknowns in determining risk rest with understanding the hydrologic factors involved in shaping the hazard.
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Ryu, Jae-Hee, Ji-Eun Kim, Jin-Young Lee, Hyun-Han Kwon, and Tae-Woong Kim. "Estimating Optimal Design Frequency and Future Hydrological Risk in Local River Basins According to RCP Scenarios." Water 14, no. 6 (March 17, 2022): 945. http://dx.doi.org/10.3390/w14060945.
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In South Korea, flood damage mainly occurs around rivers; thus, it is necessary to determine the optimal design frequency for river basins to prevent flood damage. However, there are not enough studies showing the effect of climate change on hydrologic design frequency. Therefore, to estimate the optimal design frequency according to future climate change scenarios, this study examined urban flooding area and extreme rainfall frequency that can change in the future. After estimating the optimal design frequency, hydrological risks of 413 local river basins were evaluated according to Representative Concentration Pathway (RCP) scenarios 4.5 and 8.5 after regenerating daily rainfalls from the HadGEM2-ES model into hourly rainfalls using the Poisson cluster. For the RCP 4.5, hydrological risks increased relative to the established design frequency by 3.13% on average. For the RCP 8.5, hydrological risks increased by 2.80% on average. The hydrological risks increased by 4.58% in the P2(2040–2069) period for the RCP 4.5, and by 4.39% in the P1 (2021–2039) period for the RCP 8.5. These results suggest that the hydrologic design frequency in the future will likely decrease, and the safety of river basins will also decrease.
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Caissie, Daniel, and Nassir El-Jabi. "A stochastic study of floods in Canada: frequency analysis and regionalization." Canadian Journal of Civil Engineering 18, no. 2 (April 1, 1991): 225–36. http://dx.doi.org/10.1139/l91-027.
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Peak stream discharge is a hydrologic parameter that is very important for the determination of flood risk, design of engineering works, and management of water resources. In this study, some 237 stream records across Canada were analyzed using the theory of stochastic processes applied to extreme values. This model, based on partial duration series analysis, was applied to each stream record, considering the time of occurrence of floods to be a Poisson process. In addition, exceedances (values above a given discharge level or truncation level) were considered to be independent random variables identically distributed over a one-year time interval. After this frequency analysis of each stream record, a regionalization of the flood frequency characteristics in Canada was performed using two different approaches: multiple regression analysis and index-flood method. A comparison of the two approaches was carried out by examining mean relative error and root-mean-square error. It was determined that the level of difficulty in applying the stochastic flood model was not the same across Canada. Moreover, error associated with the index-flood method is mainly due to error in estimating low return floods. Key words: flood, partial duration series, regional hydrology, index-flood method, low return flood.
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Nadeem, Muhammad Umer, Zeeshan Waheed, Abdul Mannan Ghaffar, Muhammad Mashood Javaid, Ameer Hamza, Zain Ayub, Muhammad Asim Nawaz, et al. "Application of HEC-HMS for flood forecasting in hazara catchment Pakistan, south Asia." International Journal of Hydrology 6, no. 1 (January 17, 2022): 7–12. http://dx.doi.org/10.15406/ijh.2022.06.00296.
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Floods have become more severe and frequent as a result of climate change around the world, posing a hazard to public safety and economic development. This study investigates the use of distributed hydrological models in flash flood risk management in a small watershed in Hazara, Pakistan, with the goal of improving Pakistan's early warning lead time. First, the HEC-HMS model was built using geographic data and the river network's structure, then calibrated and verified using eight high rainfall events from 2013. demonstrating that the HEC-HMS model could simulate floods in the research area Second, given that rainfall and flood events have happened, this paper proposes an analysis approach for a flood forecasting and warning system, as well as criteria for sending urban-stream flash flood alerts based on rainfall, in order to provide sufficient lead time. The DEMs (digital elevation models) of the research regions were processed using HEC-Geo HMS, an ArcView GIS tool for catchment delineation, terrain pre-processing, and basin processing. The model was calibrated and verified using previously observed data. The proposed flood prediction and risk reduction methodology is nonstructural. The Hydrologic Modeling System (HEC-HMS), which provides a sufficient lead time forecast and computes the runoff/stage threshold conditions, is at the heart of the flood warning application. For flood risk assessment, data from the Pakistan Meteorological Department (PMD) is entered into a hydro-meteorological database and then into the HEC-HMS. A server-client application was utilised to visualise the real-time flood scenario and send out an early warning message. The outcomes of this study will be used to develop flood validation measures in the Hazara stream watershed to deal with potential flash floods.
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Hanif, Asma, Ashwin Dhanasekar, Anthony Keene, Huishu Li, and Kenneth Carlson. "Flood risk assessment methodology for planning under climate change scenarios and the corresponding change in land cover." Journal of Water and Climate Change 11, no. 4 (July 24, 2019): 1370–82. http://dx.doi.org/10.2166/wcc.2019.016.
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Abstract Projected climate change impacts on the hydrological regime and corresponding flood risks were examined for the years 2030 (near-term) and 2050 (long-term), under representative concentration pathways (RCP) 4.5 (moderate) and 8.5 (high) emission scenarios. The United States Army Corps of Engineers' (USACE) Hydrologic Engineering Center's Hydrologic Modeling System was used to simulate the complete hydrologic processes of the various dendritic watershed systems and USACEs' Hydrologic Engineering Center's River Analysis System hydraulic model was used for the two-dimensional unsteady flow flood calculations. Climate projections are based on recent global climate model simulations developed for the International Panel on Climate Change, Coupled Model Inter-comparison Project Phase 5. Hydrographs for frequent (high-recurrence interval) storms were derived from 30-year historical daily precipitation data and decadal projections for both time frames and RCP scenarios. Since the climate projections for each scenario only represented ten years of data, 100-year or 500-year storms cannot be derived. Hence, this novel approach of identifying frequent storms is used as an indicator to compare across the various time frames and climate scenarios. Hydrographs were used to generate inundation maps and results are used to identify vulnerabilities and formulate adaptation strategies to flooding at 43 locations worldwide.
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Cheng, Zhengyang, Konstantine P. Georgakakos, Cristopher R. Spencer, and Randall Banks. "Numerical Modeling of Flash Flood Risk Mitigation and Operational Warning in Urban Areas." Water 14, no. 16 (August 13, 2022): 2494. http://dx.doi.org/10.3390/w14162494.
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This paper aims to demonstrate the research-to-application and operational use of numerical hydrologic and hydraulic modeling to (a) quantify potential flash flood risks in small urban communities with high spatial resolution; (b) assess the effectiveness of possible flood mitigation measures appropriate for such communities; and (c) construct an effective operational urban flash flood warning system. The analysis is exemplified through case studies pertaining to a small community with dense housing and steep terrain in Tegucigalpa, Honduras, through numerical simulations with a customized self-contained hydrologic and hydraulic modeling software. Issues associated with limited data and the corresponding modeling are discussed. In order to simulate the extreme scenarios, 24-h design storms with return periods from 1 to 100 years with distinctive temporal and spatial distributions were constructed using both daily and hourly precipitation for each month of the rainy season (May–October). Four flood mitigation plans were examined based on natural channel revegetation and the installation of gabion dams with detention basins. Due to limitations arising from the housing layout and budgets, a feasible plan to implement both measures in selected regions, instead of all regions, is recommended as one of the top candidates from a cost-to-performance ratio perspective. Numerical modeling, customized for the conditions of the case study, is proven to be an effective and robust tool to evaluate urban flood risks and to assess the performance of mitigation measures. The transition from hydrologic and hydraulic modeling to an effective urban flash warning operational system is demonstrated by the regional Urban Flash Flood Warning System (UFFWS) implemented in Istanbul, Turkey. With quality-controlled remotely sensed precipitation observations and forecast data, the system generates forcing in the hydrologic and hydraulic modeling network to generate both historical and forecast flow to assist forecasters in evaluating urban flash flood risks.
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Chen, Xing, Mukesh Kumar, and Brian L. McGlynn. "Variations in Streamflow Response to Large Hurricane-Season Storms in a Southeastern U.S. Watershed." Journal of Hydrometeorology 16, no. 1 (February 1, 2015): 55–69. http://dx.doi.org/10.1175/jhm-d-14-0044.1.
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Abstract Floods caused by hurricane storms are responsible for tremendous economic and property losses in the United States. To minimize flood damages associated with large hurricane-season storms, it is important to be able to predict streamflow amount in response to storms for a range of hydroclimatological conditions. However, this is challenging considering that streamflow response exhibits appreciable variability even for hurricane-season storms that deliver similar precipitation amounts. As such, better estimates of event responses require refined understanding of the causes of flood response variability. Here, a physically based, distributed hydrologic model and supporting hydrologic datasets are used to identify and evaluate dominant hydrologic controls on streamflow amount variability. The analysis indicates that variability in flood response in the Lake Michie watershed is primarily driven by antecedent soil moisture conditions near the land surface and evapotranspiration during postevent streamflow recession periods, which in turn is a function of precipitation history and prevailing vegetation and meteorological conditions. Presented results and ensuing analyses could help prioritize measurements during observation campaigns and could aid in risk management by providing look-up diagrams to quickly evaluate flood responses given prior information about hurricane storm size.
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Al-Futaisi, Ahmed, and Jery R. Stedinger. "Hydrologic and Economic Uncertainties and Flood-Risk Project Design." Journal of Water Resources Planning and Management 125, no. 6 (November 1999): 314–24. http://dx.doi.org/10.1061/(asce)0733-9496(1999)125:6(314).
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Sadek, Mohammed, Xuxiang Li, Eman Mostafa, Mohamed Freeshah, Ahmed Kamal, Mohamed Adou Sidi Almouctar, Fubo Zhao, and Elhadi K. Mustafa. "Low-Cost Solutions for Assessment of Flash Flood Impacts Using Sentinel-1/2 Data Fusion and Hydrologic/Hydraulic Modeling: Wadi El-Natrun Region, Egypt." Advances in Civil Engineering 2020 (August 20, 2020): 1–21. http://dx.doi.org/10.1155/2020/1039309.
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Flash floods are among the most common natural hazards in Egyptian and Arabian deserts. In this work, we utilized two Sentinel-1 and Sentinel-2 satellite images, before and after the flash flood, SRTM, and geolocated terrestrial photos captured by volunteers. This paper aims to three substantial objectives: (1) monitoring the flash flood impacts on Wadi El-Natrun region based on free satellite data and mapping the destroyed vegetation cover; (2) the integration of the free remote sensing data, geolocated terrestrial photos, and GIS techniques, along with hydrologic and hydraulic modeling, to evaluate the impact of flash flood hazards on the study area; and (3) assistance of the decision-makers in planning the required protective works to avoid the probable flooding. Two scenarios have been applied to estimate the flash flood effect. The first scenario has relied on Sentinel-1/2 data fusion before and after the flash flood, while the second scenario has been implemented based on the integration of the Sentinel-2 images and hydrologic and hydraulic flood modeling with the help of ArcGIS software to simulate the flash flood route. The results demonstrated that although the first scenario is an efficient solution for continuous monitoring of the change in the water bodies, it is limited in the detection of the submerged vegetation area. On the other hand, the second scenario provided the flash flood route and hydrological parameters, which determine the hazard degree of the basins, thus helping the decision-maker to manage the flood risk. Moreover, the second scenario surpasses the first one by estimating the destroyed infrastructure. Consequently, the second scenario is appropriate to assess the flash flood impacts and mitigate its influence in the future.
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Swain, Kishore Chandra, Chiranjit Singha, and Laxmikanta Nayak. "Flood Susceptibility Mapping through the GIS-AHP Technique Using the Cloud." ISPRS International Journal of Geo-Information 9, no. 12 (December 2, 2020): 720. http://dx.doi.org/10.3390/ijgi9120720.
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Flood susceptibility mapping is essential for characterizing flood risk zones and for planning mitigation approaches. Using a multi-criteria decision support system, this study investigated a flood susceptible region in Bihar, India. It used a combination of the analytical hierarchy process (AHP) and geographic information system (GIS)/remote sensing (RS) with a cloud computing API on the Google Earth Engine (GEE) platform. Five main flood-causing criteria were broadly selected, namely hydrologic, morphometric, permeability, land cover dynamics, and anthropogenic interference, which further had 21 sub-criteria. The relative importance of each criterion prioritized as per their contribution toward flood susceptibility and weightage was given by an AHP pair-wise comparison matrix (PCM). The most and least prominent flood-causing criteria were hydrologic (0.497) and anthropogenic interference (0.037), respectively. An area of ~3000 sq km (40.36%) was concentrated in high to very high flood susceptibility zones that were in the vicinity of rivers, whereas an area of ~1000 sq km (12%) had very low flood susceptibility. The GIS-AHP technique provided useful insights for flood zone mapping when a higher number of parameters were used in GEE. The majorities of detected flood susceptible areas were flooded during the 2019 floods and were mostly located within 500 m of the rivers’ paths.
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Xu, Chaowei, Hao Fu, Jiashuai Yang, and Lingyue Wang. "Assessment of the Relationship between Land Use and Flood Risk Based on a Coupled Hydrological–Hydraulic Model: A Case Study of Zhaojue River Basin in Southwestern China." Land 11, no. 8 (July 28, 2022): 1182. http://dx.doi.org/10.3390/land11081182.
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As an ecological consequence of intensified anthropogenic activities, more frequent extreme rainfalls have resulted in significant increases in water levels and discharge in southwestern China. This phenomenon presents a significant challenge in flood risk and ecological management. Land use is one of the major factors significantly affecting the flooding process, and it is inextricably tied to the ecological risk of floods. Hence, flood risk estimates based on land use are essential for flood control and land use planning. In this study, a coupled hydrologic–hydraulic model was developed to analyze the relationship between flood ecological risk and land use in order to provide new insights into current flood risk management practices. Ten real flood events (of different magnitudes) in the Zhaojue river basin (650 km2) were chosen to evaluate the credibility and performance of the coupled model’s application. Promising results were obtained, with sufficient reliability for flood risk assessment purposes. The results of our flood risk analysis also indicated that the model effectively reproduced overland flow and competently accounted for flood evolution. This work is significant in the understanding of the mechanism of the flood process and its relationship with land use, and it can be used in decision support for the prevention and mitigation of flood disasters and for land use planning.
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Madhuri, R., Y. S. L. Sarath Raja, K. Srinivasa Raju, Bonagiri Sai Punith, and Kondisetti Manoj. "Urban flood risk analysis of buildings using HEC-RAS 2D in climate change framework." H2Open Journal 4, no. 1 (January 1, 2021): 262–75. http://dx.doi.org/10.2166/h2oj.2021.111.
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Abstract The present study aims to assess flood depth, building risk analysis, and the effectiveness of various flood adaptation strategies to attenuate building risk caused by urban floods in climate change scenarios. A framework is proposed where a hydraulic model, Hydrologic Engineering Center's-River Analysis System 2D (HEC-RAS 2D), is applied for 2-dimensional flood modeling to estimate (a) submerged areas, (b) flood depth, and (c) building risk for extreme events corresponding to two representative concentration pathways (RCPs), 6.0 and 8.5. Greater Hyderabad Municipal Corporation (GHMC), India, is chosen for demonstration. Percentages of buildings in GHMC under high, medium, and low risks for RCP 6.0 are 38.19, 9.91, and 51.9% in the respective order, and these are 40.82, 10.55, and 48.63% for RCP 8.5. Six flood proofing (FP) strategies (S1–S6) are proposed for attenuating building risk along with the required capital cost. The capital investment required for FP to achieve the ideal situation of no risk for all buildings (strategy S6) works out to Rs. 3,740 × 107 and Rs. 3,800 × 107 for RCPs 6.0 and 8.5. It is observed that the effect of adaptation strategies is significant.
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Čepienė, Erika, Lina Dailidytė, Edvinas Stonevičius, and Inga Dailidienė. "Sea Level Rise Impact on Compound Coastal River Flood Risk in Klaipėda City (Baltic Coast, Lithuania)." Water 14, no. 3 (January 29, 2022): 414. http://dx.doi.org/10.3390/w14030414.
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Due to climate change, extreme floods are projected to increase in the 21st century in Europe. As a result, flood risk and flood-related losses might increase. It is therefore essential to simulate potential floods not only relying on historical but also future projecting data. Such simulations can provide necessary information for the development of flood protection measures and spatial planning. This paper analyzes the risk of compound flooding in the Danė River under different river discharge and Klaipėda Strait water level probabilities. Additionally, we examine how a water level rise of 1 m in the Klaipėda Strait could impact Danė River floods in Klaipėda city. Flood extent was estimated with the Hydrologic Engineering Center’s River Analysis System (HEC-RAS) and visualized with ArcGIS Pro. Research results show that a rise in the water level in the Klaipėda Strait has a greater impact on the central part of Klaipėda city, while that of the maximum discharge rates of the river affected the northern upstream part of the analyzed river section. A sea level rise of 1 m could lead to an increase in areas affected by Danė floods by up to three times. Floods can cause significant damage to the infrastructure of Klaipėda port city, urbanized territories in the city center, and residential areas in the northern part of the city. Our results confirm that, in the long run, sea level rise will significantly impact the urban areas of the Klaipėda city situated near the Baltic Sea coast.
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Zúñiga, Emmanuel, Víctor Magaña, and Violeta Piña. "Effect of Urban Development in Risk of Floods in Veracruz, Mexico." Geosciences 10, no. 10 (October 9, 2020): 402. http://dx.doi.org/10.3390/geosciences10100402.
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Urban floods have adverse effects on the population and the economy, and they are increasing in frequency and magnitude. The State of Veracruz is the region of Mexico with the highest number of disasters, more than 50% of the total number nationwide, in the 1970–2015 period. During the 1990s, disasters in this region increased from 5 to 10 events per year, mostly in relation to intense rains and floods. This study analyzes the factors that increase the risk of urban floods in the regions: (i) the Pánuco River, (ii) the Papaloapan River, and (iii) the Coatzacoalcos River regions, combining hazard data and estimates of vulnerability factors. The 95th percentile of daily precipitation (P95) is used as a threshold of heavy rain, i.e., the natural hazard. Vulnerability is estimated in terms of the percentage of natural vegetation loss due to changes in land cover and land use in the hydrological basins and the expansion of the urban areas in the regions under study. The risk of flood was compared with records of flood events focusing on the low-frequency variations of risks and disaster activity. The trends in urban flood activity are related to the loss of natural vegetation and deterioration of the basins leading to a loss of infiltration, i.e., larger runoffs. Even when the intensity of precipitation in recent decades remains without clear trends, or shows negative tendencies in the number of intense events, the number of floods is higher mostly because of the deterioration of hydrologic basins. Therefore, the risk of flooding in the state of Veracruz is mainly related to environmental factors that result in vulnerability rather than changes in the trends of extreme precipitation activity. This result means that disaster risk reduction actions should be mainly related to rehabilitation of the basins.
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Raff, D. A., T. Pruitt, and L. D. Brekke. "A framework for assessing flood frequency based on climate projection information." Hydrology and Earth System Sciences 13, no. 11 (November 10, 2009): 2119–36. http://dx.doi.org/10.5194/hess-13-2119-2009.
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Abstract. Flood safety is of the utmost concern for water resources management agencies charged with operating and maintaining reservoir systems. Risk evaluations guide design of infrastructure alterations or lead to potential changes in operations. Changes in climate may change the risk due to floods and therefore decisions to alter infrastructure with a life span of decades or longer may benefit from the use of climate projections as opposed to use of only historical observations. This manuscript presents a set of methods meant to support flood frequency evaluation based on current downscaled climate projections and the potential implications of changing flood risk on how evaluations are made. Methods are demonstrated in four case study basins: the Boise River above Lucky Peak Dam, the San Joaquin River above Friant Dam, the James River above Jamestown Dam, and the Gunnison River above Blue Mesa Dam. The analytical design includes three core elements: (1) a rationale for selecting climate projections to represent available climate projections; (2) generation of runoff projections consistent with climate projections using a process-based hydrologic model and temporal disaggregation of monthly downscaled climate projections into 6-h weather forcings required by the hydrologic model; and (3) analysis of flood frequency distributions based on runoff projection results. In addition to demonstrating the methodology, this paper also presents method choices under each analytical element, and the resulting implications to how flood frequencies are evaluated. The methods used reproduce the antecedent calibration period well. The approach results in a unidirectional shift in modeled flood magnitudes. The comparison between an expanding retrospective (current paradigm for flood frequency estimation) and a lookahead flood frequency approach indicate potential for significant biases in flood frequency estimation.
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Hardesty, Sage, Xinyi Shen, Efthymios Nikolopoulos, and Emmanouil Anagnostou. "A Numerical Framework for Evaluating Flood Inundation Hazard under Different Dam Operation Scenarios—A Case Study in Naugatuck River." Water 10, no. 12 (December 7, 2018): 1798. http://dx.doi.org/10.3390/w10121798.
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Worldwide, many river floodplains contain critical infrastructure that is vulnerable to extreme hydrologic events. These structures are designed based on flood frequency analysis aimed at quantifying the magnitude and recurrence of the extreme events. This research topic focuses on estimating flood vulnerability at ungauged locations based on an integrative framework consisting of a distributed rainfall–runoff model forced with long-term (37 years) reanalysis meteorological data and a hydraulic model driven by high-resolution airborne LiDAR-derived terrain elevation data. The framework is applied to a critical power infrastructure located within Connecticut’s Naugatuck River Basin. The hydrologic model reanalysis is used to derive 50-, 100-, 200-, and 500-year return period flood peaks, which are then used to drive Hydrologic Engineering Center’s River Analysis System (HEC-RAS) hydraulic simulations to estimate the inundation risk at the infrastructure location under different operation strategies of an upstream reservoir. This study illustrates the framework’s potential for creating flood maps at ungauged locations and demonstrates the effects of different water management scenarios on the flood risk of the downstream infrastructure.
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Wang, Yuan-Heng, Yung-Chia Hsu, Gene You, Ching-Lien Yen, and Chi-Ming Wang. "Flood Inundation Assessment Considering Hydrologic Conditions and Functionalities of Hydraulic Facilities." Water 10, no. 12 (December 19, 2018): 1879. http://dx.doi.org/10.3390/w10121879.
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This study proposed a two-phase risk analysis scheme for flood management considering flood inundation losses, including: (1) simplified qualitative-based risk analysis incorporating the principles of failure mode and effect analysis (FMEA) to identify all potential failure modes associated with candidate flood control measures, to formulate a remedial action plan aiming for mitigating the inundation risk within an engineering system; and (2) detailed quantitative-based risk analysis to employ numerical models to specify the consequences including flood extent and resulting losses. Conventional qualitative-based risk analysis methods have shown to be time-efficient but without quantitative information for decision making. However, quantitative-based risk analysis methods have shown to be time- and cost- consuming for a full spectrum investigation. The proposed scheme takes the advantages of both qualitative-based and quantitative-based approaches of time-efficient, cost-saving, objective and quantitative features for better flood management in term of expected loss. The proposed scheme was applied to evaluate the Chiang-Yuan Drainage system located on Lin-Bien River in southern Taiwan, as a case study. The remedial action plan given by the proposed scheme has shown to greatly reduce the inundation area in both highlands and lowlands. These measures was investigated to reduce the water volume in the inundation area by 0.2 million cubic meters, even in the scenario that the flood recurrence interval exceeded the normal (10-year) design standard. Our results showed that the high downstream water stage in the downstream boundary may increase the inundation area both in downstream and upstream and along the original drainage channel in the vicinity of the diversion. The selected measures given by the proposed scheme have shown to substantially reduce the flood risk and resulting loss, taking account of various scenarios: short duration precipitation, decreased channel conveyance, pump station failure and so forth.
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Abd Halim, Marhanisa, Ahmad Shakir Mohd Saudi, Mohd Khairul Amri Kamarudin, Muaz Mahmud, Arvind Bala Krishnan, and Khairul Nizam Mohd Isa. "Assessment on Regional Flood Risk Trend in Northern Region of Malaysia: Case Study in Muda River Basin, Kedah." International Journal of Engineering & Technology 7, no. 4.34 (December 13, 2018): 75. http://dx.doi.org/10.14419/ijet.v7i4.34.23584.
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Flood is a major issue during monsoon season in Northern region of Malaysia especially in Muda River Basin. This study focused on the specific hydrology parameters that lead to the flood events in Muda River Basin, Kedah. There were 4 hydrologic parameters for thirty years of collected data from selected hydrology monitoring stations provided by Department of Irrigations and Drainage, Malaysia. The study applied Principal Component Analysis (PCA) and result shown that stream flow and suspended solid stand with highest correlation of coefficient variables with the changes of water level in the study area. Statistical Process Control (SPC) applied in this study was to determine the control limit for every selected parameter obtained from PCA. The Upper Control Limit value for water level reported from SPC analysis in the study area was 7.568m and starting from this level and above, the risk of flood is high to occur in the study area. This research proved that the flood risk model created in this study was accurate and flexible for flood early warning system at Muda River Basin.
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Hoch, Jannis M., Dirk Eilander, Hiroaki Ikeuchi, Fedor Baart, and Hessel C. Winsemius. "Evaluating the impact of model complexity on flood wave propagation and inundation extent with a hydrologic–hydrodynamic model coupling framework." Natural Hazards and Earth System Sciences 19, no. 8 (August 12, 2019): 1723–35. http://dx.doi.org/10.5194/nhess-19-1723-2019.
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Abstract. Fluvial flood events are a major threat to people and infrastructure. Typically, flood hazard is driven by hydrologic or river routing and floodplain flow processes. Since they are often simulated by different models, coupling these models may be a viable way to increase the integration of different physical drivers of simulated inundation estimates. To facilitate coupling different models and integrating across flood hazard processes, we here present GLOFRIM 2.0, a globally applicable framework for integrated hydrologic–hydrodynamic modelling. We then tested the hypothesis that smart model coupling can advance inundation modelling in the Amazon and Ganges basins. By means of GLOFRIM, we coupled the global hydrologic model PCR-GLOBWB with the hydrodynamic models CaMa-Flood and LISFLOOD-FP. Results show that replacing the kinematic wave approximation of the hydrologic model with the local inertia equation of CaMa-Flood greatly enhances accuracy of peak discharge simulations as expressed by an increase in the Nash–Sutcliffe efficiency (NSE) from 0.48 to 0.71. Flood maps obtained with LISFLOOD-FP improved representation of observed flood extent (critical success index C=0.46), compared to downscaled products of PCR-GLOBWB and CaMa-Flood (C=0.30 and C=0.25, respectively). Results confirm that model coupling can indeed be a viable way forward towards more integrated flood simulations. However, results also suggest that the accuracy of coupled models still largely depends on the model forcing. Hence, further efforts must be undertaken to improve the magnitude and timing of simulated runoff. In addition, flood risk is, particularly in delta areas, driven by coastal processes. A more holistic representation of flood processes in delta areas, for example by incorporating a tide and surge model, must therefore be a next development step of GLOFRIM, making even more physically robust estimates possible for adequate flood risk management practices.
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Bianucci, P., A. Sordo-Ward, J. I. Pérez, J. García-Palacios, L. Mediero, and L. Garrote. "Risk-based methodology for parameter calibration of a reservoir flood control model." Natural Hazards and Earth System Sciences 13, no. 4 (April 18, 2013): 965–81. http://dx.doi.org/10.5194/nhess-13-965-2013.
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Abstract. Flash floods are of major relevance in natural disaster management in the Mediterranean region. In many cases, the damaging effects of flash floods can be mitigated by adequate management of flood control reservoirs. This requires the development of suitable models for optimal operation of reservoirs. A probabilistic methodology for calibrating the parameters of a reservoir flood control model (RFCM) that takes into account the stochastic variability of flood events is presented. This study addresses the crucial problem of operating reservoirs during flood events, considering downstream river damages and dam failure risk as conflicting operation criteria. These two criteria are aggregated into a single objective of total expected damages from both the maximum released flows and stored volumes (overall risk index). For each selected parameter set the RFCM is run under a wide range of hydrologic loads (determined through Monte Carlo simulation). The optimal parameter set is obtained through the overall risk index (balanced solution) and then compared with other solutions of the Pareto front. The proposed methodology is implemented at three different reservoirs in the southeast of Spain. The results obtained show that the balanced solution offers a good compromise between the two main objectives of reservoir flood control management.
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Zheng, Feifei, Michael Leonard, and Seth Westra. "Efficient joint probability analysis of flood risk." Journal of Hydroinformatics 17, no. 4 (February 9, 2015): 584–97. http://dx.doi.org/10.2166/hydro.2015.052.
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Flood attributes such as the water level may depend on multiple forcing variables that arise from common meteorological conditions. To correctly estimate flood risk in these situations, it is necessary to account for the joint probability distribution of all the relevant forcing variables. An example of a joint probability approach is the design variable method, which focuses on the extremes of the forcing variables, and approximates the hydraulic response to forcing variables with a water level table. In practice, however, application of the design variable method is limited, even for the bivariate case, partly because of the high computational cost of the hydrologic/hydraulic simulations. We develop methods to minimise the computational cost and assess the appropriate extent and resolution of the water level table in a bivariate context. Flood risk is then evaluated as a bivariate integral, which we implement as an equivalent line integral. The line integral is two orders of magnitude quicker and therefore beneficial to settings that require multiple evaluations of the flood risk (e.g., optimisation studies or uncertainty analyses). The proposed method is illustrated using a coastal case study in which floods are caused by extreme rainfall and storm tide. An open-source R package has been developed to facilitate the uptake of joint probability methods among researchers and practitioners.
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Raff, D. A., T. Pruitt, and L. D. Brekke. "A framework for assessing flood frequency based on climate projection information." Hydrology and Earth System Sciences Discussions 6, no. 2 (March 9, 2009): 2005–40. http://dx.doi.org/10.5194/hessd-6-2005-2009.
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Abstract. Flood safety is of the utmost concern for water resources management agencies charged with operating and maintaining reservoir systems. Risk evaluations guide design of infrastructure alterations or lead to potential changes in operations. Changes in climate may change the risk due to floods and therefore decisions to alter infrastructure with a life span of decades or longer may benefit from the use of climate projections as opposed to use of only historical observations. This manuscript presents a set of methods meant to support flood frequency evaluation based on current downscaled climate projections and the potential implications of changing flood risk on how evaluations are made. Methods are demonstrated in four case study basins: the Boise River above Lucky Peak Dam, the San Joaquin River above Friant Dam, the James River above Jamestown Dam, and the Gunnison River above Blue Mesa Dam. The analytical design includes three core elements: (1) a rationale for selecting climate projections to represent available climate projections; (2) generation of runoff projections consistent with climate projections using a process-based hydrologic model and temporal disaggregation of monthly downscaled climate projections into 6-h weather forcings required by the hydrologic model; and (3) analysis of flood frequency distributions based on runoff projection results. In addition to demonstrating the methodology, this paper also presents method choices under each analytical element, and the resulting implications to how flood frequencies are evaluated.
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Yuan, Fang, Yan, Sui, Ding, and Lu. "Flood-Landscape Ecological Risk Assessment under the Background of Urbanization." Water 11, no. 7 (July 10, 2019): 1418. http://dx.doi.org/10.3390/w11071418.
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The Hydrologic Modeling System (HEC-HMS) and statistical analysis method were used to analyze the relationship between flood eigenvalues (i.e., flood volume and peak flow) and landscape pattern metrics. Then, the flood-landscape ecological risk index (ERI_FL) was proposed and constructed to quantitatively assess the flood-landscape ecological risk (FLER). The semivariogram method was used to spatialize the ERI_FL values. Lastly, this study analyzed the spatial–temporal change of FLER at watershed scale and at sub-basin scale, respectively. Two historical landscape distributions (i.e., 2003 and 2017) of Qinhuai River basin were used to perform this study. The results showed that there were certain relationships between landscape pattern and flood eigenvalues, and for different landscapes, the response metrics and degrees were different. FLER increased as urbanization increased. FLER change magnitude had a positive relationship with urban land percentage change magnitude. The distribution of FLER and the distribution of FLER change both showed spatial differences at watershed scale. The structural features of landscape pattern had significant effects on regional floods. In the urbanization process, avoiding forming large-scale landscape patches, improving landscape abundance, and increasing contact area between different types of landscape patches were helpful to reduce the negative effects caused by the increase of urban landscape area on flood.
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Garcia, Matthew, Andrew Juan, and Philip Bedient. "Integrating Reservoir Operations and Flood Modeling with HEC-RAS 2D." Water 12, no. 8 (August 12, 2020): 2259. http://dx.doi.org/10.3390/w12082259.
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Current free to use models developed by the United States Army Corps of Engineers (USACE) perform unique functions (e.g., hydrology, hydraulics, reservoir operations, and flood impact analysis) that are widely used in numerous studies and applications. These models are commonly set up in a framework that is limited to point source connections, which is problematic in regions with flat topography and complex hydrodynamics. The separate models need to be integrally linked and jointly considered for accurate risk communication and decision-making, especially during major storm events. Recently, Hurricane Harvey (2017) exposed the shortcomings of the existing framework in West Harris County, TX, where an insufficient understanding of potential flood risk and impacts contributed to the extensive flood damages sustained in the region. This work illustrates the possibility of using a single hydraulic model, HEC-RAS 2D, to perform all hydrologic, hydraulic, and reservoir operations modeling necessary for accurate flood impact assessments. Implications of this study include a simplification of the entire flood impact analysis, which could help future flood risk communication and emergency planning.
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Petroselli, Andrea, Matej Vojtek, and Jana Vojteková. "Flood mapping in small ungauged basins: a comparison of different approaches for two case studies in Slovakia." Hydrology Research 50, no. 1 (August 24, 2018): 379–92. http://dx.doi.org/10.2166/nh.2018.040.
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Abstract Flood mapping is a crucial element of flood risk management. In small and ungauged basins, empirical and regionalization approaches are often adopted to estimate the design hydrographs that represent input data in hydraulic models. In this study, two basins were selected in Slovakia and different methodologies for flood mapping were tested highlighting the role of digital elevation model (DEM) resolution, hydrologic modeling and the hydraulic model. Two DEM resolutions (2 m and 20 m) were adopted. Two hydrologic approaches were employed: a regional formula for peak flow estimation and the EBA4SUB model. Two hydraulic approaches (HEC-RAS and FLO-2D) were selected. Different combinations of hydrologic and hydraulic modeling were tested, under different spatial resolutions. Regarding the DEM resolution, results showed its fundamental importance in the low relief area while its effect was secondary in the moderate relief area. Regarding the hydrologic modeling, results confirmed that it affects the results of the flood areas in the same way independently of DEM resolution and that when using event-based models, the hydrograph shape determination is fundamental. Regarding the hydraulic modeling, this was the step where major differences in the flood area estimation were found.
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Łajczak, Adam. "Changes in flood risk impacted by river training – case study of piedmont section of the Vistula river." Annals of Warsaw University of Life Sciences, Land Reclamation 46, no. 4 (December 1, 2014): 317–35. http://dx.doi.org/10.1515/sggw-2015-0006.
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Abstract Changes in flood risk impacted by river training - case study of piedmont section of the Vistula river. Main problems concerning the flood risk in piedmont section of the Vistula, Southern Poland, are discussed. This stretch of the river is channelized since the middle of the 19th century. It is part of the mainstream discussion of the effectiveness of existing river channelization methods. The following problems are analysed: (1) current state of flood risk, (2) the rate of river flow, (3) changes in flood risk since the start of channelization efforts with respect to changing channel geometry and changing rates of river flow reflecting the effects of channelization work. Substantially increased bankfull discharge in a channelized river may be considered as a stable hydrologic feature of the river stretch analysed. This means that the river is effectively reducing the quantity of water available for flooding the inter-embankment zone. This statement is the basis for analysis of changes in flood risk in the river studied. An assessment of changes in flood risk for the piedmont section of the Vistula cannot be categorical. Some changes in discharge help reduce flood risk, while others increase it. The paper is based mainly on the State Hydrological Survey data over more than the last 100 years, a large-scale maps over the last 230 years, and fieldwork conducted by the author.
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S.Ferreira, Carla, Sandra Mourato, Milica Kasanin-Grubin, António J.D. Ferreira, Georgia Destouni, and Zahra Kalantari. "Effectiveness of Nature-Based Solutions in Mitigating Flood Hazard in a Mediterranean Peri-Urban Catchment." Water 12, no. 10 (October 16, 2020): 2893. http://dx.doi.org/10.3390/w12102893.
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Urbanization alters natural hydrological processes and enhances runoff, which affects flood hazard. Interest in nature-based solutions (NBS) for sustainable mitigation and adaptation to urban floods is growing, but the magnitudes of NBS effects are still poorly investigated. This study explores the potential of NBS for flood hazard mitigation in a small peri-urban catchment in central Portugal, prone to flash floods driven by urbanization and short but intense rainfall events typical of the Mediterranean region. Flood extent and flood depth are assessed by manually coupling the hydrologic HEC-HMS and hydraulic HEC-RAS models. The coupled model was run for single rainfall events with recurrence periods of 10–, 20–, 50–, and 100–years, considering four simulation scenarios: current conditions (without NBS), and with an upslope NBS, a downslope NBS, and a combination of both. The model-simulation approach provides good estimates of flood magnitude (NSE = 0.91, RMSE = 0.08, MAE = 0.07, R2 = 0.93), and shows that diverting streamflow into abandoned fields has positive impacts in mitigating downslope flood hazard. The implementation of an upslope NBS can decrease the water depth at the catchment outlet by 0.02 m, whereas a downslope NBS can reduce it from 0.10 m to 0.23 m for increasing return periods. Combined upslope and downslope NBS have a marginal additional impact in reducing water depth, ranging from 0.11 m to 0.24 m for 10– and 100–year floods. Decreases in water depth provided by NBS are useful in flood mitigation and adaptation within the peri-urban catchment. A network of NBS, rather than small isolated strategies, needs to be created for efficient flood-risk management at a larger scale.