 As such, it included a substantial upland area of the Black Mountains, principally along the valley of the Grwyne Fawr where a reservoir was completed between 1908 and 1928.A temporary village, including school, was built on site to house construction workers and remains of this village are still visible.Lewis in 1845 described the "surrounding scenery as bold, and in some parts romantic", whereas the 1868 National Gazetteer dismissed it as "somewhat of a gloomy cast".