Abstract: A feedwell is provided for an inclined plate separator having a separation chamber containing parallel plates defining separation passages. The feedwell includes a plenum defining a plenum chamber external to the separation chamber, an upward-facing deflector surface in the plenum chamber, an inlet for discharging influent fluid onto a receiving region of the deflector surface, and an outlet for discharging the influent fluid out of the plenum and transversely into the separation chamber. The feedwell also includes parallel fins. The fins define between them plenum passages that extend from a fin end to outlet. The fin ends are disposed between the outlet and the receiving region, and are arranged in a horizontal semi-elliptical path defining a center that horizontally coincides with the receiving region.