| Summary: | 博士 === 國立中興大學 === 土木工程學系所 === 101 === Due to undulated terrain in Taiwan, most rivers are inherent in short water way, rapid flow, and high contents of sandy soils. In recent years, urban areas have been over populated and exploited. The natural resources in plain area are getting sparser. As a result, more and more projects are developed into the slope area. In order to decrease surface soil loss and minimize flooding damages in downstream area, construction of detention facilities are necessary. This study is focusing on hydraulic characteristics of detention facility.
This article firstly reviews domestic and international researches on hydraulic characteristics of detention pond and derives the continuity governing equations for Gamma inflow hydrograph with scenario of four different outlets (rectangular hole, rectangular overflow opening, Sutro outlet and Inverted-V notch outlet). The relations among the detention volume, rainfall duration, and peak reduction are also studied. On the other hand, flume experimental work of flood flowing through the detention pond is performed to verify the hydraulic characteristics of detention pond by the proposed numerical model and to understand the suitability of numerical model.
In addition, the Gamma inflow hydrograph is used as rainfall type and the theoretical model of detention pond volume is derived through analysis of non-dimensional mathematical theory. Two real cases are selected for comparison with other researchers using triangular and isosceles trapezoidal inflow hydrographs. The calculated results of detention pond volume based on triangular inflow hydrograph with characteristic value β of 1 are close to those of the real cases. Those from isosceles trapezoidal inflow hydrograph are much higher in the evaluation of detention pond volume. The results using the Gamma inflow hydrograph which is adopted in the study are in the middle of those former two types of inflow hydrographs.
This study also collects and analyzes the landform and hydrological information of build-up detention ponds in Taiwan. The related statistical graphs and data base are also constructed. With the governing equations of outlets coupled with inflow patterns, the hydraulic characteristics of detention pond and design information can be displayed in the table list through the calculation of developed window-based program. This will be helpful in the design of detention pond.
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