About Revisions Dorothea Quarry Nantle, nr Penygroes,, Caernarfon,, Wales, United Kingdom Max Depth: Over 150ft/46m Average Viz: 16-20ft/5-6m Entry Type: Shore Aquatic Life: Might See Something Spring: 50-55°F/10-13°C Summer: 61-65°F/16-18°C Fall: 50-55°F/10-13°C Winter: Under 50°F/10°C 8/13/2012 4:00 AM

Dorothea Quarry is a shore accessible fresh water dive site, located at Nantle, nr Penygroes,, Caernarfon,, Wales, United Kingdom. The maximum depth is over 150ft/46m. The average visibility is 16-20ft/5-6m.

No services at all and no safety equipment. Excellent diving location but with risks.

Introduction

The oldest quarry
in the Nantlle district was Cilgwyn quarry, this is situated to the north
of Dorothea on the hillside and is now a landfill site. It is thought
to have been first worked in the fourteenth century and it is believed
that some of Edward the 1st’s Welsh castles were roofed with Cilgwyn slate.

Dorothea
itself opened in 1820 and remained in production until 1970.
The land the quarry stands on was owned by a Richard Garnons (1774 -1841)
but the main driving force for quarrying in the valley was a Lancastrian
- William Turner (1776 -1857). The original name for the quarry
was Cloddfa Turner but it was renamed Dorothea after Gamona’s wife.
The workings grew out of a series of smaller workings with names such as
Hen Dwll, Twll Bach, Twll y Weirglodd, Twll Coch and Twll Fire. Over
the years these pits were deepened and amalgamated into the large flooded
pit seen today. Turner gave up his interest in the quarry in 1848
and following a brief period of closure it was acquired by a family called
Williams.

John
Hughes Williams was from Llangernyw near Denbigh. He married into the Rev
John Jones of Talysarn’s family & bought shares in the Company
set up by Jones & local Nantlle quarrymen (though half the money was
raised outside the area). Williams gradually bought out most
of the others by the 1860s, and his family continued in charge thereafter.

Today,
Dorothea is a popular although unofficial diving centre and sadly there
have been quite a number of divers who have lost their lives there.
There have been numerous changes of ownership of Dorothea over the years,
each successive owner promising investment and regeneration only to be
replaced by yet another optimist with yet more plans. A visit to
Dyffryn Nantlle is highly recommended before development changes the character
of this unique area for ever.



A great place to dive with lots of interesting
features. Sadly there are no facilities at all other than a rough track
and some space to park. It does get very busy at the weekend.

There are two main access points to the lake, both can be a bit tricky when laden with kit etc.








How to get there

1. Take the A4087 from the A55 and follow the road to Caernarfon.
2. In Caernarfon follow signs for Porthmadog (A487)
3. About a 2 miles from Caernarfon you will hit a roundabout. Turn left staying on the A487.
4. Follow road into Penygroes
5. In the village of Penygroes turn left along the B4418
6. Follow road to end and turn right and follow road to Nantle.
7. Shortly before Nantle you will see a large
   lake on your right, just passed this lake, on the left, is a row of
   houses, turn left along these and follow the track to the quarry. (If
   you pass the red telephone box on your left you have gone too far,
   backup about 100 yards.)
   

Typical day at Dotty

Map (Click to enlarge -125Kb)