Top Entrance

Station 2. Top Entrance, Porth Yr Ogof

Top entrance is on the east bank of the river Mellte and is about 1.5m above the dry river bed. Google Earth co-ordinates: 51°48’04.85”N 3°33’17.88”W

Elevation 255m SN 92881253

Top entrance from the opposite river bank

A small entrance in the river bed is only accessible in dry weather and after a couple of metres of muddy stooping, a small sump pool is reached on the left. Do not attempt to document this site if the river is flowing significantly. For a diver to enter the water, it is necessary to reverse downslope through a short, tight squeeze. The passage then opens up and to the west of this passage is ‘Parkers horror’ which are two small passages leading to the Upper cave.

Christine reverses into Top Entrance (sump)

Continuing down-slope from Top entrance leads to 4-ways junction. North (East) leads to Cobbet’s Loop which develops into a pleasant, scalloped tube which surfaces 32m later in Upper Cave Water Chamber (UCWC). Further upstream passages can be explored including Essers Passage (named after Paul Esser who sadly died on a cave dive here in 1971) and Esser’s bypass. Further sumps can be explored beyond UCWC.


How to record data:

Photo: Stand opposite the entrance if the river is running. get closer if the river is dry enough to cross. Take a photo of the river entrance (see above). 

Temperature: If you are diving, take note of the temperature on your depth gauge/computer.
If you are not diving, attempt to take a temperature reading in the sump and make a note of the instrument you used.

Observations: Take a note of the condition of the line if you are diving. You do not need to take a visibility reading as it is almost impossible not to destroy the visibility by entering Top entrance sump. Take note of any flora or fauna in the immediate area of Top Entrance. You may note things such as spiders, invertebrates and ferns.