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Guo W.-D.,Taiwan Typhoon and Flood Research Institute TTFRI | Feng W.-S.,Taiwan Typhoon and Flood Research Institute TTFRI | Wang Y.-C.,Taiwan Typhoon and Flood Research Institute TTFRI | Ho H.-Y.,Taiwan Typhoon and Flood Research Institute TTFRI
International Journal of Automation and Smart Technology | Year: 2011

Hydrological issues in metropolises in Taiwan have become increasingly important because the storm water sewer systems of metropolises are frequently unable to meet the requirements of the existing and future metropolitan development. Typhoons or torrential rains that cause rainfall intensities that exceed the designed capacity of storm water sewers can result in serious flooding. The losses caused by flooding can be reduced if the areas at risk of flooding can be predicted and warnings can be issued to prompt disaster prevention and allow response units and residents to prepare before disasters occur. The primary purpose of this study is to integrate the quantitative precipitation forecasting technologies [1, 2] developed by the Taiwan Typhoon and Flood Research Institute to establish a rapid, stable, real-time, and automatic metropolitan area flood estimation system for predictive flooding analysis. The objects of this study are metropolitan areas in Taiwan with storm water sewer systems. The standard capacities of storm water sewer systems throughout Taiwan and the geographic information system (GIS) shape files are collected and compiled. Additionally, the potential flooding areas are divided into four levels (high, medium, low, and no flooding) and are compared with the rainfall warning values of the Water Resources Agency. The study combines the results of quantitative precipitation forecasts, establishes an information database (MySQL), processes Google Earth KML files, and designs a WEB GIS display interface to construct a system for estimating the flooding possibility (probability) in metropolitan areas during typhoons or torrential rains. This study subsequently employs the event of Typhoon Kalmaegi for flooding estimation and display; the estimation results are consistent with the flooding survey data, indicating that the estimations made by the flooding estimation system are correct. © 2011 International Journal of Automation and Smart Technology.

Chan H.-C.,National Chung Hsing University | Lin P.-W.,National Chung Hsing University | Peng J.-S.,National Chung Hsing University | Peng J.-S.,Water Resources Agency | Hong J.-H.,Taiwan Typhoon and Flood Research Institute TTFRI
Journal of Chinese Soil and Water Conservation | Year: 2016

This paper aims to analyze temporal evolutions of pier scour in live-bed condition. Five steady flow experiments are conductedwith different flow intensitiesratio of mean velocity to critical velocity varying from 1.18 to 2.21. To find out the effects of unsteady flow on scour depth, different steady flow intensities were combined as four unsteady flow experiments, including: (1) advanced hydrograph, (2) delayed hydrograph, (3) symmetric hydrograph and (4) symmetric hydrograph with low peak. A semi-empirical model proposed by Hong et al. (2014) was used topredict thetemporal variation of pier-scour depth. Moreover, alinear-combination hypothesis, i.e. scour depth hydrograph of unsteady flow can be simulated by a linear-combination ofscour depth hydrographs of steady flows,was proposed to extend Hong et al.'s model inunsteady flow conditions. Comparison of the experimental and model resultsshowed that the present modeldid not perform perfectly on the variation of dune migration velocity with changing flow intensity is changing. Simulation and experiment resultsrevealed a phase difference because of the effect of dune migration velocity.However,the error betweenthe simulatedand experimentalscour depths ranged from 8% to10%, including that the present modelcan estimate the temporal variationof scour depth for cyliderical piersunder unsteady flow conditionsreasonably well. © 2016, Chinese Soil and Water Conservation Society. All right reserved.

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