Pwll Cwm Sych

Location


Grid Reference: SN 691 183

Altitude: 350m

On the open mountain between Llygad Llwchwr resurgence and Herbert's Quarry.

Access
Open access, but please replace the cover over the entrance shaft after exiting.

Description
Length: ~ 10m

Vertical range: ~ 9m

Pwll Cwm Sych (meaning Pool or Pit of the dry valley) is a large sink on open mountain. An initial scaffolded shaft of about 3m leads to a crawl. To the right is a loose collapse chamber. To the left is a second scaffolded shaft of about 6m depth. The second shaft may be partially filled with in-washed peat.

On the surface, surrounded by a fence, there is a large collapse fissure (~8m wide and ~4m deep) where the cliff has parted to fall towards the sink. The stream has been diverted into this fissure but rejoins the main dig part way down the second shaft, the water draining into cracks at its base.

The site is one of major significance, being the most active sink for the Llygad Llwchwr system, taking water in all but the driest of weather. The sink lies some 2.5km from the rising and approximately 130m higher.

History
Dug by Rhys Williams et al (SWCC) between 1997 and 2001. The fissure was excavated by members of SWCC in about 1988 and the main sink by members of Hereford CC in about 1966.