Tarns of the Lake District

Tarns are situated in various different locations, both at lower level valley plains and mountainous regions of the Lake District; bygone reminders of their glacial origins. They can change form due to alluvial disposition made by the constant run off from becks (mountains streams) that, over long periods of time, silt up the adjacent land with sand, gravel and clay, making some areas incredibly fertile, particularly those on valley floors. Many tarns are natural, a work of art in nature’s canvass, crafting and forming an ever-changing scenery that will some day be unrecognisable to our present-day eyes. There are some tarns, however, the result of human intervention, created for our increasing need for clean drinking water, dammed and turned into reservoirs or simply for aesthetics, such as that fine example seen in the Victorian landscaped Tarn Hows, near Coniston.

Cirque tarns
But take a moment to think about what a tarn actually is: a small body of water that is usually formed in mountainous hollows or corries, also known as glacial cirques. These are bowl-shaped, ice-excavated rock basins, some of which are naturally deep, once carved by millions of tonnes of ice, erosion and weather. Cirques typically have three steep sides containing a headwall and two enclosing sidewalls, with a fourth being more open where a glacial till or moraine (rock debris that formed a dam) eventually enclosed and trapped the remaining ice. Some of the best examples of a cirque tarn are Blea Water, Angle Tarn, Stickle Tarn, Blind Tarn and Scale Tarn. Water will usually flow from the moraine, ensuring the tarn maintains a fairly constant depth, and continue its journey down towards another tarn or lake via a network of becks and a river as seen at Little Langdale Tarn before eventually flowing into a larger body of water, in this case, Windermere.

These mountainous tarns are unlike their lower altitude relatives found in the outlying fells (and various other locations in the northwest) where they look more like large ponds. While a number of these will be natural, others will be man-made, once serving different industrial purposes.

Etymology
The word tarn, used extensively throughout the northwest and in particular the Lake District, has Old Norse origins with an eventual and what appears to be a subtle shift into late 14 century Middle English, typically meaning a "small mountain lake". It is also a dialectal word popularised by Lakeland poets. Here, we can see the word-shift and how it developed through time:
 * Proto-Germanic ternō → a reconstructed word meaning a small lake or water hole
 * Old Norse tjörn → meaning a small mountain lake, pond or pool
 * Middle English terne (alternative tarne) → meaning a lake, pond or pool

It should also be noted that tarn is also cognate with other Scandinavian languages: Danish and Norwegian tjern (small forest or mountain lake), Faroese tjørn (pond), Icelandic tjörn (pond) and Swedish tjärn (small forest lake), all of which have the same or very similar meanings.

It seems apparent that tarn is a word synonymous with its Scandinavian origins. Norse influences dominate the very words we use today to describe the much loved places that draw hundreds of thousands of tourists each year to its Lakeland charms. Yet, this simple, unassuming word tarn occurs in over seventy names, a testament to the prevalence of an ancient language not from these shores. Whilst the definition of a tarn would typically originate from the Old Norse "small mountain lake or pool," this definition cannot stretch to every occurrence where tarn is used. Therefore, we could surmise that some tarns have been named thus in more recent times to fulfil a more general definition that suits a small lake, pond or pool without the "mountain" counterpart its lofty relatives are so uniquely associated.