WANGWen-liang,RUANJia-yue,SUCheng-qing,et al.Methodology for Assessing Emptying Time of Stormwater Bioretention Facilities[J].China Water & Wastewater,2025,41(6):53-56.
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Methodology for Assessing Emptying Time of Stormwater Bioretention Facilities

China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU] volume: 第41卷 Number: 第6期 Page: 53-56 Column: Date of publication: 2025-03-17
Author(s):
WANG　Wen-liang1;  RUAN　Jia-yue1;  SU　Cheng-qing1;  GUO　Chwenyuan2;  LI　Jun-qi1;  REN　Zi-qiang3;  LI　Yun-jie4
（1. Key Laboratory of Urban Stormwater System and Water Environment ，Beijing University of Civil Engineering and Architecture， Beijing 100044， China； 2. University of Colorado， The United States of America； 3. Wuhu City Drainage Management Office， Wuhu 241005， China； 4. Shanghai Municipal Engineering Design Institute Co. Ltd.， Shanghai 200092， China）
Keywords:
stormwater bioretention facility;  emptying time;  surface ponding layer;  structural layer
Abstract:
Emptying time constitutes a critical design and operational parameter for stormwater bioretention facilities, and it can be categorized into surface ponding layer emptying time and structural layer emptying time. This paper proposed a calculation method for emptying time under both constant head and variable head conditions. The specific formula could be derived based on the flow capacity of the bottom drain under constant head conditions. Under a variable head, after determining the emptying time, the flow coefficient of the bottom drain of the bioretention facility could be further calculated and used as an input parameter for the low impact development (LID) module in SWMM. This method is capable of assessing the operational effectiveness of bioretention facilities and determining the infiltration performance of soil media as well as coarse sand and graded gravel.
Last Update: 2025-03-17