scholarly journals Assessment of Flood Hazard and Agriculture Damage Under Climate Change in the Bagmati River Basin of Nepal

2019 ◽  
Vol 8 (2) ◽  
pp. 55-69 ◽  
Author(s):  
Badri Bhakta Shrestha

Assessment of flood hazard and damage is a prerequisite for flood risk management in the river basins. The mitigation plans for flood risk management are mostly evaluated in quantified terms as it is important in decision making process. Therefore, analysis of flood hazards and quantitative assessment of potential flood damage is very essential for mitigating and managing flood risk. This study focused on assessment of flood hazard and quantitative agricultural damage in the Bagmati River basin including Lal Bakaiya River basin of Nepal under climate change conditions. Flood hazards were simulated using Rainfall Runoff Inundation (RRI) model. MRI-AGCM3.2S precipitation outputs of present and future climate scenarios were used to simulate flood hazards, flood inundation depth, and duration. Flood damage was assessed in the agricultural sector, focusing on flood damage to rice crops. The flood damage assessment was conducted by defining flood damage to rice crops as a function of flood depth, duration, and growth stage of rice plants and using depth-duration-damage function curves for each growth stage of rice plants. The hazard simulation and damage assessment were conducted for 50- and 100-year return period cases. The results show that flood inundation area and agricultural damage area may increase in the future by 41.09 % and 39.05 % in the case of 50-year flood, while 44.98 % and 40.76 % in the case of 100-year flood. The sensitivity to changes in flood extent area and damage with the intensity of return period was also analyzed.

2015 ◽  
Vol 15 (6) ◽  
pp. 1297-1309 ◽  
Author(s):  
K. M. de Bruijn ◽  
F. Klijn ◽  
B. van de Pas ◽  
C. T. J. Slager

Abstract. For comprehensive flood risk management, accurate information on flood hazards is crucial. While in the past an estimate of potential flood consequences in large areas was often sufficient to make decisions on flood protection, there is currently an increasing demand to have detailed hazard maps available to be able to consider other risk-reducing measures as well. Hazard maps are a prerequisite for spatial planning, but can also support emergency management, the design of flood mitigation measures, and the setting of insurance policies. The increase in flood risks due to population growth and economic development in hazardous areas in the past shows that sensible spatial planning is crucial to prevent risks increasing further. Assigning the least hazardous locations for development or adapting developments to the actual hazard requires comprehensive flood hazard maps. Since flood hazard is a multi-dimensional phenomenon, many different maps could be relevant. Having large numbers of maps to take into account does not, however, make planning easier. To support flood risk management planning we therefore introduce a new approach in which all relevant flood hazard parameters can be combined into two comprehensive maps of flood damage hazard and flood fatality hazard.


2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Chaochao Li ◽  
Xiaotao Cheng ◽  
Na Li ◽  
Zhongmin Liang ◽  
Yanyan Wang ◽  
...  

With growing flood risk due to increased urbanization, flood damage assessment and flood risk management must be reconsidered. To demonstrate and assess the new features and trends of flood risk in urbanized areas, a novel S-shaped function of return period and damage(R-D)is proposed. The function contains three parameters, which are defined as the maximum flood damageA, critical return periodRc, and integrated loss coefficientk. A basic framework for flood damage assessment was established to evaluate flood damage in the Taihu Basin under various scenarios. The simulation results were used to construct the floodR-Dfunctions. The study results show that the floodR-Dmodel based on the Gompertz function agrees well with the mutability of flood damage in the highly urbanized basin when the flood scale exceeds the defense capability. TheR-Dfunction can be utilized for timely and effective flood damage assessment and prediction. It can describe the impacts of socioeconomic development, urbanization degree, and flood control capability improvements well. The turning points of the function curve can be used as gradation criteria for rational strategy development associated with flood hazards.


2016 ◽  
Vol 16 (2) ◽  
pp. 349-369 ◽  
Author(s):  
U. C. Nkwunonwo ◽  
M. Whitworth ◽  
B. Baily

Abstract. Urban flooding has been and will continue to be a significant problem for many cities across the developed and developing world. Crucial to the amelioration of the effects of these floods is the need to formulate a sound flood management policy, which is driven by knowledge of the frequency and magnitude of impacts of these floods. Within the area of flood research, attempts are being made to gain a better understanding of the causes, impacts, and pattern of urban flooding. According to the United Nations office for disaster reduction (UNISDR), flood risk is conceptualized on the basis of three integral components which are frequently adopted during flood damage estimation. These components are: probability of flood hazard, the level of exposure, and vulnerabilities of elements at risk. Reducing the severity of each of these components is the objective of flood risk management under the UNISDR guideline and idea of “living with floods”. On the basis of this framework, the present research reviews flood risk within the Lagos area of Nigeria over the period 1968–2012. During this period, floods have caused harm to millions of people physically, emotionally, and economically. Arguably over this period the efforts of stakeholders to address the challenges appear to have been limited by, amongst other things, a lack of reliable data, a lack of awareness amongst the population affected, and a lack of knowledge of flood risk mitigation. It is the aim of this research to assess the current understanding of flood risk and management in Lagos and to offer recommendations towards future guidance.


Water Policy ◽  
2017 ◽  
Vol 19 (6) ◽  
pp. 1081-1096 ◽  
Author(s):  
Ľ. Solín ◽  
M. Sládeková Madajová ◽  
L. Michaleje

Abstract The aims of this paper are to present knowledge about the threat of flooding in the upper basins of the Myjava River, obtained using a questionnaire, and to identify the potential lessons for flood risk management. The questionnaire was designed to obtain information about households' experience with flooding, including the type of floods experienced, the locations of flooding, the exacerbating factors contributing to flood risk that they considered to be important and their proposals to minimise the occurrence of flooding. Findings obtained using the questionnaire suggest that: (i) in the upper basins, sheetwash flooding is as important as river flooding and the assessment of flood hazards should include all significant types of flood hazard; (ii) flood risk management in the upper basins should primarily focus on the systematic maintenance of small watercourses and on eliminating local factors that increase the risk of all types of flooding. The building of structures for flood defence should be seen as a last resort when other options are not effective.


Climate ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 125
Author(s):  
Khalid Oubennaceur ◽  
Karem Chokmani ◽  
Yves Gauthier ◽  
Claudie Ratte-Fortin ◽  
Saeid Homayouni ◽  
...  

In Canada, climate change is expected to increase the extreme precipitation events by magnitude and frequency, leading to more intense and frequent river flooding. In this study, we attempt to map the flood hazard and damage under projected climate scenarios (2050 and 2080). The study was performed in the two most populated municipalities of the Petite Nation River Watershed, located in southern Quebec (Canada). The methodology follows a modelling approach, in which climate projections are derived from the Hydroclimatic Atlas of Southern Quebec following two representative concentration pathways (RCPs) scenarios, i.e., RCP 4.5 and RCP 8.5. These projections are used to predict future river flows. A frequency analysis was carried out with historical data of the peak flow (period 1969–2018) to derive different return periods (2, 20, and 100 years), which were then fed into the GARI tool (Gestion et Analyse du Risque d’Inondation). This tool is used to simulate flood hazard maps and to quantify future flood risk changes. Projected flood hazard (extent and depth) and damage maps were produced for the two municipalities under current and for future scenarios. The results indicate that the flood frequencies are expected to show a minor decrease in peak flows in the basin at the time horizons, 2050 and 2080. In addition, the depth and inundation areas will not significantly change for two time horizons, but instead show a minor decrease. Similarly, the projected flood damage changes in monetary losses are projected to decrease in the future. The results of this study allow one to identify present and future flood hazards and vulnerabilities, and should help decision-makers and the public to better understand the significance of climate change on flood risk in the Petite Nation River watershed.


2015 ◽  
Vol 3 (1) ◽  
pp. 123-159
Author(s):  
K. M. de Bruijn ◽  
F. Klijn ◽  
B. van de Pas ◽  
C. T. J. Slager

Abstract. For comprehensive flood risk management, accurate information on flood hazards is crucial. While in the past an estimate of potential flood consequences in large areas was often sufficient to make decisions on flood protection, there currently is an increasing demand to have detailed hazard maps available to be able to consider other risk reducing measures as well. Hazard maps are a prerequisite for spatial planning, but can also support emergency management, the design of flood mitigation measures, and the setting of insurance policies. The increase in flood risks due to population growth and economic development in hazardous areas in the past shows that sensible spatial planning is crucial to prevent risks increasing further. Assigning the least hazardous locations for development or adapting developments to the actual hazard requires comprehensive flood hazard maps. Since flood hazard is a multi-dimensional phenomenon, many different maps could be relevant. Having large numbers of maps to take into account does, however, not make planning easier. To support flood risk management planning we therefore introduce a new approach in which all relevant flood hazard parameters can be combined into two comprehensive maps of flood damage hazard respectively flood fatality hazard.


2007 ◽  
Vol 56 (4) ◽  
pp. 87-95 ◽  
Author(s):  
A. Winterscheid

It is now commonly accepted that the management of flood risks has to be fulfilled within an integrated framework. About two decades ago flood risk was managed from a limited perspective predominantly by means of structural measures aimed at flood control. In contrast integrated flood risk management incorporates the complete management cycle consisting of the phases prevention, protection and preparedness. In theory it is a well described concept. In the stage of implementation, however, there is often a lack of support although a consistent policy framework exists. Consequently, the degree of implementation must be rated as inadequate in many cases. In particular this refers to the elements which focus on preparedness and prevention. The study to which this paper refers emphasises the means and potentials of scenario technique to foster the implementation of potentially appropriate measures and new societal arrangements when applied in the framework of integrated flood risk management. A literature review is carried out to reveal the state-of-the-art and the specific problem framework within which scenario technique is generally being applied. Subsequently, it is demonstrated that scenario technique is transferable to a policy making process in flood risk management that is integrated, sustainable and interactive. The study concludes with a recommendation for three applications in which the implementation of measures of flood damage prevention and preparedness is supported by scenario technique.


Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 896
Author(s):  
Thanh Thu Nguyen ◽  
Makoto Nakatsugawa ◽  
Tomohito J. Yamada ◽  
Tsuyoshi Hoshino

This study aims to evaluate the change in flood inundation in the Chitose River basin (CRB), a tributary of the Ishikari River, considering the extreme rainfall impacts and topographic vulnerability. The changing impacts were assessed using a large-ensemble rainfall dataset with a high resolution of 5 km (d4PDF) as input data for the rainfall–runoff–inundation (RRI) model. Additionally, the prediction of time differences between the peak discharge in the Chitose River and peak water levels at the confluence point intersecting the Ishikari River were improved compared to the previous study. Results indicate that due to climatic changes, extreme river floods are expected to increase by 21–24% in the Ishikari River basin (IRB), while flood inundation is expected to be severe and higher in the CRB, with increases of 24.5, 46.5, and 13.8% for the inundation area, inundation volume, and peak inundation depth, respectively. Flood inundation is likely to occur in the CRB downstream area with a frequency of 90–100%. Additionally, the inundation duration is expected to increase by 5–10 h here. Moreover, the short time difference (0–10 h) is predicted to increase significantly in the CRB. This study provides useful information for policymakers to mitigate flood damage in vulnerable areas.


Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1513
Author(s):  
Yar M. Taraky ◽  
Yongbo Liu ◽  
Ed McBean ◽  
Prasad Daggupati ◽  
Bahram Gharabaghi

The Kabul River, while having its origin in Afghanistan, has a primary tributary, the Konar River, which originates in Pakistan and enters Afghanistan near Barikot-Arandu. The Kabul River then re-enters Pakistan near Laalpur, Afghanistan making it a true transboundary river. The catastrophic flood events due to major snowmelt events in the Hindu Kush mountains occur every other year, inundating many major urban centers. This study investigates the flood risk under 30 climate and dam management scenarios to assess opportunities for transboundary water management strategy in the Kabul River Basin (KRB). The Soil and Water Assessment Tool (SWAT) is a watershed-scale hydraulic modeling tool that was employed to forecast peak flows to characterize flood inundation areas using the river flood routing modelling tool Hydrologic Engineering Center - River Analysis System -HEC-RAS for the Nowshera region. This study shows how integrated transboundary water management in the KRB can play a vital catalyst role with significant socio-economic benefits for both nations. The study proposes a KRB-specific agreement, where flood risk management is a significant driver that can bring both countries to work together under the Equitable Water Resource Utilization Doctrine to save lives in both Afghanistan and Pakistan. The findings show that flood mitigation relying on collaborative efforts for both upstream and downstream riparian states is highly desirable.


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