Abstract Climate change increases the probability of extreme rainfall events, which results in la... more Abstract Climate change increases the probability of extreme rainfall events, which results in large-scale flooding in urban areas. Yet, urban areas are often too crowded to build flood detention facilities. To cope with this issue, this study developed a simplified design method of a permeable pavement system. Firstly, the detention volume calculation method for the underground detention pond was established. Secondly, a novel permeable pavement system named JW pavement was used as an example to verify the feasibility of the development method for the underground detention pond. Thirdly, the surface infiltration rate and the void ratio of a gravel layer were measured. Finally, the equation of the thickness required for the gravel layer was established based on the requirement of flood detention volume. To sum up, the thicker a gravel layer is, the more capable a gravel layer is to protect the city from flooding. The urban flood can be reduced by the combination of a high surface infiltration rate permeable pavement system and a thick underground detention pond.
Abstract. This study established the estimation method of rainfall distribution for small catchme... more Abstract. This study established the estimation method of rainfall distribution for small catchment. The Kriging method was introduced to establish the spatial distribution model of rainfall depth, where the cross validation is executed to verify the theoretical semi-variogram model. A field experiment with an area of 3.33ha was executed for nearly three years in southern Taiwan, and obtained the rainfall depth data from 167 rainfall events of 12 rainfall stations. After the statistical analysis, we found that the Gaussian model is suitable to establish the theoretical semi-variogram of rainfall depth, so as to estimate the rainfall depth of ungauged region.
This paper presents the theoretical equations for the impact characteristics of free over-fall (I... more This paper presents the theoretical equations for the impact characteristics of free over-fall (ICFOF) in the pool zone with sloping upstream bed. The various impact characteristics considered are the brink depth, the impact position and impact angle, the tail water depth and the depth of water pool. In order to overcome the complexity in determining the ICFOF, they were expressed in dimensionless forms as functions of upstream bed slope (UBS), upstream Froude number and Drop number. The multiple regression analysis was used to obtain the empirical expressions for the ICFOF using the laboratory experimental results. It was found that the dimensionless brink depth decreases with an increase in upstream Froude number and UBS. With the increase in both the Drop number and UBS, the dimensionless impact position increases, while the impact angle decreases. On the other hand, the dimensional tail water depth and the dimensional depth of water pool vary directly with the Drop number and in...
This study developed a real-time remote monitoring system (RTRMS) for monitoring hillslope precip... more This study developed a real-time remote monitoring system (RTRMS) for monitoring hillslope precipitation using a software system analysis and design methods named unified modeling language (UML). The system structure thus developed comprises three subsystems for gathering/storage/transmission (GST), receiving/sending/control (RSC) and storage/display (SD). The RTRMS also has an embedded system which uses solar energy as the power supply and the General Packet Radio Service (GPRS) modem for wireless transmission. This study also develops the specifications for designing the solar power system. The developed RTRMS has been put to use in the watershed of Chen Yu Lan Creek, Nantou County, Taiwan, so as to verify the system stability. According to the records of battery voltage, the maximum battery voltage within a day is around noon while the minimum is around midnight.
AbstractThis paper established a laboratory-scale model with multiphysics coupling computation to... more AbstractThis paper established a laboratory-scale model with multiphysics coupling computation to estimate the scour depth of the pier. The model employed governing equations based on structural dy...
The purpose of this study is to develop the feed-forward back-propagation neural network (FFBPNN)... more The purpose of this study is to develop the feed-forward back-propagation neural network (FFBPNN) to estimate the groundwater level (GL) of next hour according the current GL and past precipitation depth in the hillslope. The 72-h precipitation depth and the real-time groundwater levels are used as the model output layer determination variables. The output variables, are type 1, the GL, which has been used in many researches, and type 2, the groundwater level fluctuation (GLF), which is the difference between the current-time and the next-time groundwater level. The order of the water level fluctuation is less than that of the groundwater level by about one order of magnitude (ten times). The landslide area at the downstream of Wu-She Reservoir, Nantou County, Taiwan, is adopted as a field test area. Total 328 cases of Sinlaku typhoon were used to establish the prediction model of real-time GL. Another 327 cases of Jangmi typhoon were adopted to illustrate the model application. The result of model application shows that root-mean-square error of type 2 (=0.104 m) is smaller than that of type 1 (=0.408 m). In conclusion, the forecasting method used GLF gives a much better agreement with the measured values than that of GL.
Abstract Climate change increases the probability of extreme rainfall events, which results in la... more Abstract Climate change increases the probability of extreme rainfall events, which results in large-scale flooding in urban areas. Yet, urban areas are often too crowded to build flood detention facilities. To cope with this issue, this study developed a simplified design method of a permeable pavement system. Firstly, the detention volume calculation method for the underground detention pond was established. Secondly, a novel permeable pavement system named JW pavement was used as an example to verify the feasibility of the development method for the underground detention pond. Thirdly, the surface infiltration rate and the void ratio of a gravel layer were measured. Finally, the equation of the thickness required for the gravel layer was established based on the requirement of flood detention volume. To sum up, the thicker a gravel layer is, the more capable a gravel layer is to protect the city from flooding. The urban flood can be reduced by the combination of a high surface infiltration rate permeable pavement system and a thick underground detention pond.
Abstract. This study established the estimation method of rainfall distribution for small catchme... more Abstract. This study established the estimation method of rainfall distribution for small catchment. The Kriging method was introduced to establish the spatial distribution model of rainfall depth, where the cross validation is executed to verify the theoretical semi-variogram model. A field experiment with an area of 3.33ha was executed for nearly three years in southern Taiwan, and obtained the rainfall depth data from 167 rainfall events of 12 rainfall stations. After the statistical analysis, we found that the Gaussian model is suitable to establish the theoretical semi-variogram of rainfall depth, so as to estimate the rainfall depth of ungauged region.
This paper presents the theoretical equations for the impact characteristics of free over-fall (I... more This paper presents the theoretical equations for the impact characteristics of free over-fall (ICFOF) in the pool zone with sloping upstream bed. The various impact characteristics considered are the brink depth, the impact position and impact angle, the tail water depth and the depth of water pool. In order to overcome the complexity in determining the ICFOF, they were expressed in dimensionless forms as functions of upstream bed slope (UBS), upstream Froude number and Drop number. The multiple regression analysis was used to obtain the empirical expressions for the ICFOF using the laboratory experimental results. It was found that the dimensionless brink depth decreases with an increase in upstream Froude number and UBS. With the increase in both the Drop number and UBS, the dimensionless impact position increases, while the impact angle decreases. On the other hand, the dimensional tail water depth and the dimensional depth of water pool vary directly with the Drop number and in...
This study developed a real-time remote monitoring system (RTRMS) for monitoring hillslope precip... more This study developed a real-time remote monitoring system (RTRMS) for monitoring hillslope precipitation using a software system analysis and design methods named unified modeling language (UML). The system structure thus developed comprises three subsystems for gathering/storage/transmission (GST), receiving/sending/control (RSC) and storage/display (SD). The RTRMS also has an embedded system which uses solar energy as the power supply and the General Packet Radio Service (GPRS) modem for wireless transmission. This study also develops the specifications for designing the solar power system. The developed RTRMS has been put to use in the watershed of Chen Yu Lan Creek, Nantou County, Taiwan, so as to verify the system stability. According to the records of battery voltage, the maximum battery voltage within a day is around noon while the minimum is around midnight.
AbstractThis paper established a laboratory-scale model with multiphysics coupling computation to... more AbstractThis paper established a laboratory-scale model with multiphysics coupling computation to estimate the scour depth of the pier. The model employed governing equations based on structural dy...
The purpose of this study is to develop the feed-forward back-propagation neural network (FFBPNN)... more The purpose of this study is to develop the feed-forward back-propagation neural network (FFBPNN) to estimate the groundwater level (GL) of next hour according the current GL and past precipitation depth in the hillslope. The 72-h precipitation depth and the real-time groundwater levels are used as the model output layer determination variables. The output variables, are type 1, the GL, which has been used in many researches, and type 2, the groundwater level fluctuation (GLF), which is the difference between the current-time and the next-time groundwater level. The order of the water level fluctuation is less than that of the groundwater level by about one order of magnitude (ten times). The landslide area at the downstream of Wu-She Reservoir, Nantou County, Taiwan, is adopted as a field test area. Total 328 cases of Sinlaku typhoon were used to establish the prediction model of real-time GL. Another 327 cases of Jangmi typhoon were adopted to illustrate the model application. The result of model application shows that root-mean-square error of type 2 (=0.104 m) is smaller than that of type 1 (=0.408 m). In conclusion, the forecasting method used GLF gives a much better agreement with the measured values than that of GL.
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