Character Analysis and Experimental Verification of Stepped Detention Volumes

• Main Authors: Hong-Yu Chen, 陳宏宇
• Other Authors: Jen-Yan Chen
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/55321574650058257684

碩士 === 國立中興大學 === 土木工程學系 === 92 === The purpose of the study is to explore the design of stepped detention ponds so as to reduce the demanded pond volume and to relieve the peak flood under the consideration of safety. In the study, the detention pond system contained two separated pond spaces. A simplify model and a hydrological model were used to calculate the smallest detention volume of the pond. By introducing six different triangular inflow hydrographs (T1~T6), furthermore, a series of detention pond experiments (120 runs), with four different inside pond widths ( =14~20cm) and four different full water-levels ( =18.7 ~26.2cm) of the outer pond as well as five types of spillway outlets ( =1.0~3.3cm), were performed to verify the results of the former models. The conclusions are summarized as follows： 1. As confirmed by the experiments, the hydrology continuity equation according to the Runge-Kutta method can be adopted to evaluate the minimum detention volume of the pond ( ) accurately. Moreover, equations (3-19) to (3-21), proposed in the simplified model, can be handily used to calculate the dimensionless inside detention pond volume ( ), outside detention pond volume ( ) and the minimum detention volume ( ). 2. The results of the series of flume experiments show that the extent of peak reduction becomes more significant as and decrease. In addition, the detention volume reduction ratio (δ) becomes smaller as decreases. 3. The regression equations (5-3a)、(5-3b) can be applied to obtain the relatively minimum detention volume ( ). Compared with the experimental results by Wu, it shows that stepped detention pond system is beneficial to detention volume reduction as the dimensionless outflow peak discharge ( ) is about 0.45.