Hydrodynamic separation of suspended particles using curved channels offers advantages in many applications, since it is a fast continuous flow technology that can handle neutrally and near neutrally buoyant particles without the need of a physical barrier or the addition of chemical aids. Designs are provided for a flow splitter at the end of the separation channel, to maintain smooth, counter-vortex-free laminar flow and improve particle separation efficiency while reducing clogging and fouling propensities.