Evaluation of a first-flush capture and detention tank receiving runoff from an asphalt-paved road

摘要

In this article, we propose and examine a first-flush capture and detention tank (FCDT) working as a first flush capture device and pretreatment unit receiving stormwater runoff from an asphalt-paved road. We design the FCDT to completely capture all the stormwater including a first flush generated by an initial 5 mm effective rainfall depth, and to bypass the exceeding part. According to our analysis based on the data from field monitoring and SWMM simulation for 27 events from April to June, 2015, the tank captured 35% of total runoff, which resulted in catching 74% of the TSS load. The TSS mass detention attained in this study by capturing the first 35% of the total runoff is close to the typical definition of a first flush, and also justifies the need for a first-flush friendly treatment.