To aid the construction of the docks at Port Talbot, the river was impounded and a diversion channel built that now forms the lower reaches of this river. There are two weirs in this final tidal reach of the Afan; Greenpark Weir at the upstream tidal limit, which has been reconstructed in 2017 and provides headwaters for the dock feeder channel that approximately follows the river's original route, and Newbridge Weir, which is the most downstream weir, presents a barrier to fish passage and is in a poor state of repair.