*In [[bioretention]] the freeboard is the difference between the invert elevation of the [[overflow]] structure and the [[inlet]]. 150 mm will suffice, so long as the inlet will not become inundated during design storm conditions. | *In [[bioretention]] the freeboard is the difference between the invert elevation of the [[overflow]] structure and the [[inlet]]. 150 mm will suffice, so long as the inlet will not become inundated during design storm conditions. |