Twrch Brook culvert and overflow sluice on the Neath Canal

The Twrch Brook culvert and overflow sluice on the Neath Canal is a low tunnel constructed from rubble stone, featuring a segmental arch and a sluice opening downstream beneath a high rubble stone embankment wall. The arch is made of thin stone voussoirs, some of which are now eroded. Above the arch, there is a square sluice outlet with a large stone lintel. The walling consists of squared stone laid in courses and does not have a parapet. On the canal side, there is a sluice control mechanism with a wooden frame and a metal gate. The upstream side, located on the east side of the road, is much lower and includes a small segmental arch, a 20th-century low wall, and white painted railings.