This paper discusses an effective test protocol for evaluating the sediment retention efficiency of proprietary stormwater treatment systems. The sump of a full-scale treatment device is filled with a known mass of sediment or sediment tracer. The unit is run at steady-state for a specified duration that exceeds several multiples of its effective detention time. Repeated tests are undertaken at different flow rates and the amount of material retained in the device for each flow rate is determined. The sediment retention efficiency is then calculated based on a comparison between mass of material retained in the sump after running flows through the unit and the original mass of material deposited in the sump.

Test data using this protocol for different device configurations are discussed and this highlights the importance of chamber geometry and hydrodynamic regime on the sediment retention efficacy of stormwater treatment devices.