Work on building the dam across the river Rheidol near the foot of Pumlumon Fawr to store water for the Cwm Rheidol Hydro Electricity Scheme was begun at the end of the 1950s. Before the Nant-y-Moch valley was flooded the two brothers, John a Jim James had to vacate their smallholding and the nearby chapel closed. Today the reservoir is a popular tourist attraction so the mountain road from the dam to Tal-y-bont alongside the reservoir and especially through Cwm Ceulan.
