Daniau Village in Daniau Creek Watershed,Taitung County,Taiwan,sustained damages from landslides and mudflows during Typhoon Morakot in 2009.The purpose of this study is to adopt the FLO2D numerical model recognized b...Daniau Village in Daniau Creek Watershed,Taitung County,Taiwan,sustained damages from landslides and mudflows during Typhoon Morakot in 2009.The purpose of this study is to adopt the FLO2D numerical model recognized by Federal Emergency Management Agency(FEMA) to simulate the mudflow,and the Daniau Village was used as a case study,along with rainfall and digital terrain data for this simulation.On the basis of sediment yields,the residual sediment volume in the landslide area was determined to be 33,276 m 3 by comparison of digital elevation models(DEMs) and by using the universal soil loss equation(USLE).In addition,this study performed a hydrological frequency analysis of rainfall to estimate the flow discharge as conditions of the simulation.Results of disaster surveys were collected to compare with outputs of the numerical model.Results of the simulation conducted with FLO2D indicated that if the countermeasure was not destroyed,the drainage work would function without overflow.This study aimed to review the effectiveness of countermeasure on the basis of simulation results obtained by using the model to provide references for future disaster prevention and resident evacuation plans.展开更多
This present study develops a 2-D numerical scheme to simulate the velocity and depth on the actual terrain by using shallow water equations. The computational approach uses the HLL scheme as a basic building block, t...This present study develops a 2-D numerical scheme to simulate the velocity and depth on the actual terrain by using shallow water equations. The computational approach uses the HLL scheme as a basic building block, treats the bottom slope by lateralizing the momentum flux, then refines the scheme using the Strang splitting to deal with the frictional source term. Besides, a decoupled algorithm is also adopted to compute the aggradation and degradation of bed-level elevation by using the Manning-Strickler formula and Exner’s relationship. The main purpose is to set up the window interface of 2-D numerical model and increase the realization of engineers on these characteristics of hydraulic treatment and maintenance.展开更多
In recent years, global warming has gradually become obvious, thus created the climate change. Typhoon Morakot attacked Taiwan and brought heavy rainfall in August, 2009. In mountainous areas including Central and Sou...In recent years, global warming has gradually become obvious, thus created the climate change. Typhoon Morakot attacked Taiwan and brought heavy rainfall in August, 2009. In mountainous areas including Central and South Taiwan, the flood and debris flow disasters were induced by the typhoon. In this study, Changhua City is selected as the research region and the Delphi method is employed to interview experts and establish comprehensive evaluation criteria for assessing the evacuation plan on disaster areas. The concept is to combine the landslide potential analysis by geographic information systems with the flood or debris flow maps into the potential hazard map. Meanwhile, analytic hierarchy method (AHP) is comprehensively carried on the expert questionnaire survey for the potential hazard map of the compound disaster states. It should be useful for the local government and native people in the future.展开更多
基金supported in part by the National Science Council (NSC 97-2313-B-270-001-MY3) and Taitung Branch,Soil and Water Conservation Bureau, Council of Agriculture,Taiwan
文摘Daniau Village in Daniau Creek Watershed,Taitung County,Taiwan,sustained damages from landslides and mudflows during Typhoon Morakot in 2009.The purpose of this study is to adopt the FLO2D numerical model recognized by Federal Emergency Management Agency(FEMA) to simulate the mudflow,and the Daniau Village was used as a case study,along with rainfall and digital terrain data for this simulation.On the basis of sediment yields,the residual sediment volume in the landslide area was determined to be 33,276 m 3 by comparison of digital elevation models(DEMs) and by using the universal soil loss equation(USLE).In addition,this study performed a hydrological frequency analysis of rainfall to estimate the flow discharge as conditions of the simulation.Results of disaster surveys were collected to compare with outputs of the numerical model.Results of the simulation conducted with FLO2D indicated that if the countermeasure was not destroyed,the drainage work would function without overflow.This study aimed to review the effectiveness of countermeasure on the basis of simulation results obtained by using the model to provide references for future disaster prevention and resident evacuation plans.
文摘This present study develops a 2-D numerical scheme to simulate the velocity and depth on the actual terrain by using shallow water equations. The computational approach uses the HLL scheme as a basic building block, treats the bottom slope by lateralizing the momentum flux, then refines the scheme using the Strang splitting to deal with the frictional source term. Besides, a decoupled algorithm is also adopted to compute the aggradation and degradation of bed-level elevation by using the Manning-Strickler formula and Exner’s relationship. The main purpose is to set up the window interface of 2-D numerical model and increase the realization of engineers on these characteristics of hydraulic treatment and maintenance.
文摘In recent years, global warming has gradually become obvious, thus created the climate change. Typhoon Morakot attacked Taiwan and brought heavy rainfall in August, 2009. In mountainous areas including Central and South Taiwan, the flood and debris flow disasters were induced by the typhoon. In this study, Changhua City is selected as the research region and the Delphi method is employed to interview experts and establish comprehensive evaluation criteria for assessing the evacuation plan on disaster areas. The concept is to combine the landslide potential analysis by geographic information systems with the flood or debris flow maps into the potential hazard map. Meanwhile, analytic hierarchy method (AHP) is comprehensively carried on the expert questionnaire survey for the potential hazard map of the compound disaster states. It should be useful for the local government and native people in the future.
