Effects of Design and Climate on Bioretention Effectiveness for Watershed-Scale Hydrologic Benefits

Bioretention areas are a common form of green stormwater infrastructure (GSI). There is significant research on the performance individual bioretention cells, but watershed-scale benefits GSI still unclear. Furthermore, differences in design and rainfall patterns make it difficult to compare results between studies. We used Storm Water Management Model (SWMM) assess effects size, soil infiltration rate, storm climate GSI. first divided contiguous US into 10 regions based similarities precipitation amount, intensity, other characteristics. then modeled single watershed under these different regimes. did provide benefits, although declined as (1) became smaller, (2) rates decreased, (3) depth increased. High-intensity was primary cause outflow from areas, back-to-back events also caused some climates. were clear discrepancies subbasin-scale performance. Generally, runoff volume reduction greater when measured at subbasin scale. Peak flow reduction, however, watershed-scale, likely because changed shape hydrographs, leading peak that than sum parts. recommendations for design, management, future help advance effective application achieving hydrologic benefits.