AN ASSESSMENT OF POTENTIAL CLIMATE CHANGE IMPACTS ON FLOOD RISK IN CENTRAL VIETNAM

Flood is a natural feature of the environment and is also one the most frequent hazardous natural disaster. The impacts of flood are highly devastating and usually causing economic depression and direct damages to the livelihood, properties, and lives of the people. In recent years, the extended flat territory along the long coastline with the tropical cyclone frequency is result of flood problem in the central region of Vietnam. In an attempt to deal with this adversity, this paper aims to manifest the feasibility of assessing flood simulations that corresponds to the impacts of climate change. The system was developed using the outputs of the Hadley Centre Coupled Model, version 3 (HadCM3) for A2 and B2 scenarios and a coupling of hydrological – hydrodynamic models. The results indicated that the weather will become hotter in the future with the increase of temperature between 0.4°C to 2.2°C and 0.19°C to 0.6°C under A2 and B2 scenarios, respectively. On the other hand, the annual rainfall will also increase between 3.3% to 14.5% and 3.6% to 6.8% under A2 and B2 scenarios, respectively. The results also demonstrated that potentially serious increases in runoff and water level under future climate change scenarios. The unanticipated consequences might play a large role in destruction of crops, transportation, water supply, and communities located in the Huong River Basin. Additionally, the outcomes of this study can be applied for the entire Huong River Basin in order to mitigate the flood problems in the future

Interactions between land use and flood management in the Chi River Basin

The damages and hardships caused by floods and flooding remain an issue and are continuously increasing in the Chi River Basin, Thailand. It is difficult to make an accurate assessment of the costs and consequences associated with floods. However, flood hazards can also be seen as an opportunity, a chance to correct possible flaws and ambiguities in the flood management. The Chi River system cannot handle the regularly occurring floods, consequently, flooding of the low-lying areas occurs on a regular basis. Therefore, an integrated flood management framework needs to be developed to minimize the negative effects of floods of different magnitude. In response, a hydrological model (SWAT) and a hydraulic (1D/2D SOBEK) model were integrated to simulate floods in detailed way and to analyse the current system. A reliable simulation of the river flows and inundated areas is an essential component of a holistic flood management plan. The developed modelling framework enabled to analyse the impact of different structural measures such as river normalisation, green river (bypass), and retention basin. In addition, non-structural measures including reservoir operation and spatial land use planning were assessed in their capability to protect people and valuable infrastructure. For each measure, several possible scenarios were tested and evaluated based on economic and technical efficiency criteria to determine the most promising and efficient scenario. However, effective interventions may involve a judicious combination of flood mitigation approaches, rather than reliance on a stand-alone solution. A truly optimum combination of aforesaid measures was then chosen since it could considerably reduce flood extent and its damage. Finally, the study illustrates the effects of land use changes on floods, which indicated little or no significant potential impact on flood regime at river basin level, but rather at sub-basin scale. This finding is important for a better understanding of the scale and direction of impacts of developments in the future. Integrated land use planning was shown to be an essential component of a comprehensive flood management framework. &nbsp

Drought severity assessment in the lower Nam Phong River Basin, Thailand

Drought is a disastrous-triggering agent that exacerbates environmental services and socio-economic conditions. Considering the impact of climate change and rainfall deficiency over the extended period, the need for a systematic way to understand drought is necessary. Therefore, this research proposed to perform an assessment of drought severity in the lower Nam Phong River Basin, Thailand using the Standardize Precipitation Index (SPI) and Water Evaluation and Planning (WEAP) model. The findings demonstrated consistent results between the SPI index and WEAP model in determining drought severity impacts. It was found that Kosum Phisai, Nam Phong, and Muang Khon Kaen Districts were the most drought affected areas. The drought risk areas were identified and classified into four zones based on the size of the affected area in %: less (25%); moderate (27%); high (22%); and extreme (26%). The outcome results can be useful for water resources planning and drought severity management in other parts of Thailand

Interactions between land use and flood management in the Chi River Basin; Proefschrift Wageningen en UNESCO-IHE Institute for Water Education Delft.

The Chi River Basin, Thailand, cannot handle the regularly occurring floods. Consequently, flooding of the low-lying areas occurs on a regular basis. Therefore, an integrated flood management framework needs to be developed to minimize the negative effects of floods of different magnitude. In response, a hydrological model (SWAT) and a hydraulic model (1D/2D SOBEK) were integrated to simulate river flows and inundated areas, and to analyse the current system. The developed modelling framework enables to analyse the impacts of different structural measures such as river normalisation, green river (bypass), and retention basin. In addition, non-structural measures including reservoir operation and land use planning were assessed in their capability to protect people and valuable infrastructure. For each measure, several possible scenarios were tested and evaluated based on financial and technical efficiency criteria. An 'optimum' combination of aforesaid measures was chosen since it could reduce flood extent and its damage more considerably than stand-alone solutions. Finally, the study illustrates the effects of land use changes on floods, which indicated little or no significant potential impact on flood regime at river basin level, but rather at sub-basin scale. This is important for a better understanding of the scale and direction of impacts of developments in the future

Participation level of water users in irrigated water management: A case study of Ban Vern Kham Pumping irrigation project, Xaithani district, Vientiane capital, Lao PDR

The objective of this research was to study the participation of water user group in irrigated water management in Ban Vern Kham Pumping Irrigation Project, Xaithani District, Vientiane Capital, Lao PDR, through the analysis of variables and the formulation of participation equation. The study included 105 households for data collection based on the developed questionnaires. The collected data were analyzed using SPSS program and expressed in the forms of frequency, percentage, mean, and standard deviation. The analysis of participation variables and stepwise multiple regression was carried out to obtain the equation used to predict the participation level in irrigated water management. Based on the main findings, the overall participation level was reported to be high, which was equal to 3.62 (the total score of 5.00) with the standard deviation of 0.149. Specifically, the participation in planning irrigation water allocation and operation and maintenance of irrigation system obtained the same highest score of 3.67, whereas the least score was the participation in allocating the benefit from irrigation water (with the score of 3.53). Additionally, the personal factors of water users were found not affecting the participation level. However, the different education level played a role in participation level in irrigation water allocation planning with the statistical significance of 0.05. The other factors such as education level, working ability, and income obtained from water user group, were found to have a moderate relationship with participation level. The analysis revealed that the water user group was relatively well established due to a strong cooperation and collaboration in working together to find equitable ways to manage irrigation water. In conclusion, the participation level in irrigated water management was a function of working ability, income obtained from water user group, and position in water user group

Effect of Material Uncertainties on Fatigue . . .

The present paper deals with the e#ect of uncertainties on the prediction of fatigue failure of aerospace and mechanical components. Typically the design of such structures has been based on costly experiments or modified versions of Paris law which are applicable to very restricted range of conditions. The present formulation employs cohesive zone elements in order to resolve the fractured zone in combination with an extrapolation scheme that makes the analysis over hundred of thousands of cycles computationally e#cient. The e#ect of randomness in the cohesive strength is examined with respect to the total lifetime of the specimen