Rainwater collection systems typically incorporate a first flush mechanism to divert pollutants from stored rainwater, with the design usually based on capturing the initial 1-2 mL of rainfall. However, variations in the local environment and collection systems can affect the required first flush volume. We conducted experiments in Amherst, Massachusetts to evaluate rainwater quality per collection volume and time, finding variable dissolved organic carbon concentrations in first flush samples. Our results identify a need to tailor first flush designs that consider local precipitation patterns, storm intensity, and canopy conditions.
Charlebois B., Reckhow, D., Wittbold, P., E. Kumpel (2023). Effective First Flush Volumes in Rainwater Catchment Systems. AQUA – Water Infrastructure, Ecosystems and Society. In publication. DOI:10.2166/aqua.2023.049