What specific operational design feature allows detention basins to effectively reduce peak flood flows downstream?

The specific operational design feature that allows detention basins to effectively reduce peak flood flows downstream is the restricted outlet structure. This structure, engineered into the basin's design, is a controlled opening—such as a small culvert, an orifice, or a weir—that purposefully limits the rate at which water can discharge from the basin. During a rainfall event, stormwater runoff, which is water flowing over land, rapidly enters the detention basin. The inflow....