Hydro International’s First Defense vortex separator has received approval from Indianapolis, Ind. for use as a stormwater quality unit, demonstrating its ability to meet the toughest regulatory design requirements. The First Defense is one of only a few devices approved for use in an online configuration in Indianapolis. The First Defense is capable of accommodating higher flow rates without the risk of washing out the sediments and pollutants captured in the device, or causing surface water flooding.