Event mean concentration and first flush effect from different drainage systems and functional areas during storms
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Updated: Mar 30, 2026

Capturing Flow-weighted Water and Suspended Particulates from Agricultural Canals During Drainage Events
Published on: November 7, 2017
Hai-Qin Peng1, Yan Liu2, Hong-Wu Wang1
1National Engineering Research Center for Urban Pollution Control, Tongji University, 1239 Siping Road, Shanghai, 200092, China.
Abstract:
This study aimed to investigate the characteristics of the event mean concentration (EMC) and first flush effect (FFE) during typical rainfall events in outfalls from different drainage systems and functional areas. Stormwater outfall quality data were collected from five outfalls throughout Fuzhou City (China) during 2011-2012. Samples were analyzed for water quality parameters, such as COD, NH3-N, TP, and SS. Analysis of values indicated that the order of the event mean concentrations (EMCs) in outfalls was intercepting combined system > direct emission combined system > separated system. Most of the rainfall events showed the FFE in all outfalls. The order of strength of the FFE was residential area of direct emission combined system > commercial area of separated system > residential area of intercepting combined system > office area of separated system > residential area of separated system. Results will serve as guide in managing water quality to reduce pollution from drainage systems.
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