Ogof Hesp Alyn
Encyclopedia
Ogof Hesp Alyn was discovered by North Wales Caving Club in 1973 in the Alyn Gorge
near Cilcain
, Flintshire
, Wales
. Reaching the end of the cave is a serious commitment requiring one pitch series and the draining of two sumps.
With more recent discoveries, the length of cave passage totals 2 kilometres (1.2 mi) extending over a vertical range of about 90 metres (295.3 ft). The entrance would have functioned as a rising prior to the lowering of local water levels by mine drainage. As drainage only took place in the early 20th century, Ogof Hesp Alyn provides a valuable opportunity to study a cave system developed almost entirely by a phreatic
processes which remains largely unmodified by vadose
streams.
It lies close to another cave, Ogof Hen Ffynhonnau, which lies about 150 metres (164 yd) further upstream in the Alyn Gorge. These two caves with Ogof Nadolig
form the caves part of the Alyn Valley Woods and Alyn Gorge Caves SSSI.
Alyn Gorge
The Alyn Gorge is a spectacular forested gorge section of the River Alyn north between Loggerheads and Rhydymwyn in Wales. The west side of the valley rises gently to Moel Famau, while the east bank is along parts a cliff with evidence of tram lines and old quarry workings.The path along the edge...
near Cilcain
Cilcain
Cilcain is a small community, near Mold in Flintshire, north-east Wales. The village has an industrial history and includes the Millennium Woods, a post office, a public house, a parish church and a village hall....
, Flintshire
Flintshire
Flintshire is a county in north-east Wales. It borders Denbighshire, Wrexham and the English county of Cheshire. It is named after the historic county of Flintshire, which had notably different borders...
, Wales
Wales
Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...
. Reaching the end of the cave is a serious commitment requiring one pitch series and the draining of two sumps.
With more recent discoveries, the length of cave passage totals 2 kilometres (1.2 mi) extending over a vertical range of about 90 metres (295.3 ft). The entrance would have functioned as a rising prior to the lowering of local water levels by mine drainage. As drainage only took place in the early 20th century, Ogof Hesp Alyn provides a valuable opportunity to study a cave system developed almost entirely by a phreatic
Phreatic
The term phreatic is used in Earth sciences to refer to matters relating to ground water below the water table . The term 'phreatic surface' indicates the location where the pore water pressure is under atmospheric conditions...
processes which remains largely unmodified by vadose
Vadose zone
The vadose zone, also termed the unsaturated zone, is the portion of Earth between the land surface and the top of the phreatic zone i.e. the position at which the groundwater is at atmospheric pressure . Hence the vadose zone extends from the top of the ground surface to the water table...
streams.
It lies close to another cave, Ogof Hen Ffynhonnau, which lies about 150 metres (164 yd) further upstream in the Alyn Gorge. These two caves with Ogof Nadolig
Ogof Nadolig
Ogof Nadolig is a cave in the Alyn Gorge near Cilcain, Flintshire, North Wales. It is mostly crawling, long, and ends with a shaft up to the surface and a locked manhole cover....
form the caves part of the Alyn Valley Woods and Alyn Gorge Caves SSSI.
External links
- North Wales Caving Club
- Countryside Council for Wales
- http://www.cowdery.org.uk/hesp.php