Navigable channel

A navigable channel is a waterway with depth, width, and alignment maintained for safe vessel passage, marked by aids to navigation and held to an authorized depth by dredging. Its depth equals the design vessel draft plus gross under-keel clearance for squat, wave response, and a safety margin; its width is built up in beams of the design vessel for the maneuvering lane plus wind, current, and traffic allowances. The channel is charted, surveyed to IHO S-44 order, and buoyed under the IALA Maritime Buoyage System so a navigator can hold the centerline. Maintenance dredging restores depth as sediment shoals the bed between surveys.