text: HDS systems should be sized based on treatment objectives including desired level of pollutant removal, drainage basin characteristics, climate of the region, and particle size to be targeted. Performance is also sensitive to water temperature, i.e. season. Care must be taken to avoid routing excess flow through the device and compromising performance. Each vendor’s product has different pollutant removal rates that should be evaluated before selecting the system.
  The Technology Assessment Protocol-Ecology (TAPE) and Technology Acceptance and Reciprocity Partnership (TARP) are evaluation programs sponsored by several state agencies in the U.S. These programs include lab and field testing and provide specific sizing criteria for hydrodynamic separation systems.
  Currently, the Environmental & Water Resources Institute (a component of the American Society of Civil Engineers) and ASTM International are developing comprehensive verification guidelines and standard test methods for assessing the performance of these devices.