If you’ve ever wondered why water quality controls can be so much smaller than water quantity controls (and honestly, who hasn’t), when that means only a small fraction of the rainwater is getting treated—this is why!
Parker “Austin Needs Approval Voting” Welch
You absolutely can improve water quality with small detention volumes though, because what you really need to capture is that first flush of rainwater carrying all the surface pollutants (suspended solids, metals…etc)
The rain that falls after that is much larger in volume, but much less dirty
