What Secrets Lie Beneath Llyn Tegid’s Mysterious Waters?

Llyn Tegid, also known as Bala Lake, stands as Wales’ largest natural lake, a 3.5-mile-long glacial marvel in Gwynedd, drawing water sports enthusiasts, anglers, and myth-seekers to its peaceful waters in Snowdonia National Park.

Llyn Tegid measures 3.5 miles long and 0.75 miles at its widest point, covering 1,196 acres (4.84 km²), making it Wales’ largest natural lake. Situated in Gwynedd, within Snowdonia National Park, the lake lies in a glacial valley along the fault line between Bala and Tal-y-Llyn, fed by the River Dee, which originates on the slopes of Dduallt.

The lake’s level has been artificially controlled by sluices since around 1804, with modifications by Thomas Telford to supply water for the Ellesmere Canal (later Llangollen Canal).

Comparison with Other Lakes

While Llyn Tegid is the largest natural lake, reservoirs like Llyn Trawsfynydd (1,180 acres), Lake Vyrnwy (1,120 acres), and Llyn Brenig (894 acres) follow closely in surface area, but all are artificial. Llangorse Lake, the largest natural lake in South Wales, ranks as the second-largest natural lake overall.

Significance

The town of Bala, once a pivotal center for the North Wales woollen trade, sits on the lake’s north-eastern end, built on a recessional moraine from the last ice age that dammed the valley to form Llyn Tegid. The lake’s level was raised by Thomas Telford’s sluices to support the Ellesmere Canal, with further modifications in the 1950s by the Dee and Clwyd River Authority to manage flooding and supply water to Huntington near Chester, England. The 3-mile Bala Lake Railway, running along the lake’s south-eastern shore from Bala to Llanuwchllyn, uses a former section of the Ruabon–Barmouth line.

Toponyms and Naming

Historically, Gerald of Wales recorded the lake as Penmelesmere in the 12th century, while other names like Pymplwy meer, Pimble-mere, and Pemble Mere referenced the five parishes of Llandderfel, Llanfawr, Llanycil, Llanuwchllyn, and Llangywer. The modern Welsh name, Llyn Tegid, first appeared in the 1568 Cronica Walliae, translating to “Lake of Beauty” from the Welsh word teg (fair).

The English name “Bala Lake,” derived from bala (outlet of a lake), has sparked controversy, with the Eryri National Park Authority voting in 2023 to prioritize Llyn Tegid in English usage.

Wildlife and Environmental Management

Unique Species

Llyn Tegid hosts abundant fish species, including pike, perch, brown trout, roach, and eel, and is home to the critically endangered gwyniad, a fish unique to this lake, threatened by the invasive ruffe. The rare mollusc Myxas glutinosa (glutinous snail) also resides here.

Environmental Challenges

In the 1990s, Llyn Tegid suffered from blue-green algae blooms, indicating eutrophication. The Environment Agency, in partnership with the water industry and farming community, implemented a plan to reduce pollution inputs. The lake’s water level, managed by sluices between 159.2m and 163.5m OD, stores approximately 18,000,000 m³ of water for the River Dee regulation system, aiding flood control and water supply to the Wirral.

Recreational Appeal

Llyn Tegid is a hub for water sports, including paddleboarding, canoeing, windsurfing, sailing, kayaking, and trout fishing, supported by two sailing clubs and boat hire companies. Since the early 19th century, Bala has been a tourist destination, with visitor numbers growing after the advent of railways and motor vehicles. The surrounding Penllyn region, with its Aran, Arenig, and Berwyn mountain ranges, offers hiking, cycling over Bwlch y Groes (1,800ft/545m), and access to nearby mountain bike trail centers.

Mythological and Folklore Connections

In Welsh mythology, Llyn Tegid is tied to Tegid Foel, husband of the goddess Ceridwen, whose court was said to have drowned beneath the lake’s waters, visible on moonlit nights according to the poet Taliesin. A variant folktale describes a walled spring near the lake that, when left unsecured, flooded a nearby town to form the lake.

Welsh folklore associates Llyn Tegid with an afanc, a lake monster. In 1909, Marie Trevelyan recorded a tale of a diver encountering a coiled dragon-like creature at the lake’s bottom. Modern sightings, reported since the 1920s, include water disturbances and a 1970s account by lake manager Dowie Bowen of an 8-foot crocodile-like creature. 

A 1979 fisherman reported a hump-backed beast, prompting investigations, including a Japanese film crew’s use of diving equipment and a submarine in the 1990s, though no evidence was found. The lake’s 40-meter depth and plentiful fish support speculation about a large predator’s survival.

Penllyn and Welsh Culture

Llyn Tegid lies in Penllyn, a rural region with a strong Welsh identity where Welsh is widely spoken as a first language. Surrounded by high mountains, deep valleys, forests, and rivers like the Tryweryn and Dee, Penllyn offers a calm contrast to crowded Snowdonia areas, with attractions like beaches, nature reserves, and heritage railways nearby. In 2017, Lonely Planet named North Wales one of the world’s best regions to visit, highlighting Bala and Penllyn as ideal bases.

Conclusion

Llyn Tegid, Wales’ largest natural lake at 1,196 acres, anchors the Penllyn region’s natural beauty and cultural heritage, offering water sports, unique wildlife like the gwyniad, and a rich tapestry of myths from Tegid Foel to the elusive “Teggie.”

Its glacial origins, historical importance tied to Bala’s wool trade, and modern environmental management underscore its enduring appeal as a Snowdonia gem, inviting visitors to experience its tranquil waters and lively