This lake is straddled by the A2 road viaduct, though there was no obvious way by which the 2 sides were connected under the road when I swam, with a small space to park at the east end of the viaduct.
The lake is included in the Geologist Association’s top 100 UK sites because it fills (in as little as a day) and empties rapidly (within a few days) leaving just a deep muddy hole. Check this link to the Geology Survey Northern Ireland video on YouTube , or this one on the Geology Society web site, or search on-line where you will find pictures showing it empty and quite deep!
In many nearby locations it is apparent that there is a thick chalk bed over-layered with basalt and at the lake itself an additional layer of peat. Whilst the basalt itself is quite waterproof and made more so by the peat it seems the bottom of the lake has hole in it through which the water drains down into the porous chalk.
The road was not always raised on a viaduct and could be flooded for weeks on end. On one occasion in 1898 when it was flooded Colonel John Magee McNeille ordered his coachman to drive through the lake on the line of the road but the coach got off the road and the horses and occupants were lost and now their ghosts apparently haunt the lake.
None of this: ghosts or the chance the water would suddenly vanish, nor the incessant rain, was of course going to put me off swimming the entire circumference of the lake.
The water is dark with peat, very dark, like cola, but not as cold as maybe it might have been given the general lack of sunshine and incessant rain of the past week; necessary factors of course for there to even be a lake. I set off beneath the island of cairns, each one tipped with a white glint of chalk only reinforcing the impression of dragons teeth.
Cars slow on the road, maybe to look at the lake, maybe to look at the swimmer as somehow I don’t think this sort of thing happens very frequently. I pretend I am not in a goldfish bowl, but I am in a goldfish bowl there’s no escaping the fact.
There’s a patch of blue sky overhead and the scene brightens for a short while but the sunshine only sweeps the far hillside coming nowhere close and then the gloom lowers again.
Reeds brush my legs. At this point I have no idea about the geology and history of the lake, maybe just as well, and I have no idea about how much vanishing goes on though the very top flowers of a foxglove just poking through the surface give me some sense of how flooded the lake must be. The sheep look on disdainfully as I reach ‘the far side’ where one of the streams that feeds water runs in chattering noisily amongst mossy stones. Extraordinarily I have already been swimming 20 minutes, it is further around than it looks (I find out later that it is over 1/2 a mile).
It is however a swim of 2 very unequal halves and the second half takes less than 15 minutes. Finally I bump the stones back where I started to find Gerald keeping watch over my towel and the sheep at bay.
It has been a rather wonderful moment that I cannot imagine I will be repeating.