One dam on the Rappahannock River and twelve dams on the James River were identified as actual or potential barriers to the upstream spawning migrations of Virginia's anadromous fishes. Elimination of these barriers by breaching, in the case of unused facilities, or by the construction of fish passage facilities would result in the restoration of 47 miles of mainstem river (a 30% increase) on the Rappahannock and 226 miles (a 200% increase) on the James.