The Hydro-Brake Flow Control a self-activating device that uses vortex principles to control and attenuate stormwater flow. The system harnesses the energy inherent in the flow field. They have no moving parts and no external energy requirements. With clear openings up to 600% larger than conventional flow control devices, the risk of blockage is reduced to a minimum. In addition, the unique head/ discharge characteristics reduce storage volume requirements, lowering project costs.