Malham Tarn is a

glacial lake A glacial lake is a body of water with origins from glacier activity. They are formed when a glacier erodes the land and then melts, filling the depression created by the glacier. Formation Near the end of the last glacial period, roughly 10,0 ...

near the village of Malham in the

Yorkshire Dales The Yorkshire Dales are a series of valleys, or Dale (landform), dales, in the Pennines, an Highland, upland range in England. They are mostly located in the Ceremonial counties of England, ceremonial county of North Yorkshire, but extend into C ...

, England. The lake is one of only eight upland alkaline lakes in Europe. At an altitude of above sea level it is the highest marl lake in the United Kingdom. Its

geology Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth ...

flora Flora (: floras or florae) is all the plant life present in a particular region or time, generally the naturally occurring (indigenous (ecology), indigenous) native plant, native plants. The corresponding term for animals is ''fauna'', and for f ...

and

fauna Fauna (: faunae or faunas) is all of the animal life present in a particular region or time. The corresponding terms for plants and fungi are ''flora'' and '' funga'', respectively. Flora, fauna, funga and other forms of life are collectively ...

have led to it being listed under a number of conservation designations. The site is currently owned by the

National Trust The National Trust () is a heritage and nature conservation charity and membership organisation in England, Wales and Northern Ireland. The Trust was founded in 1895 by Octavia Hill, Sir Robert Hunter and Hardwicke Rawnsley to "promote the ...

, who used to lease part of the site to the

Field Studies Council Field Studies Council is an educational charity based in the UK, which offers opportunities for people to learn about and engage with the outdoors. History The organisation was established as the Council for the Promotion of Field Studies in ...

but this closed as a field centre in 2022. The site was the inspiration for

Charles Kingsley Charles Kingsley (12 June 1819 – 23 January 1875) was a broad church priest of the Church of England, a university professor, social reformer, historian, novelist and poet. He is particularly associated with Christian socialism, the workin ...

's 1863 novel '' The Water-Babies, A Fairy Tale for a Land Baby''.

Geography

Malham Tarn is situated in the

, a

national park A national park is a nature park designated for conservation (ethic), conservation purposes because of unparalleled national natural, historic, or cultural significance. It is an area of natural, semi-natural, or developed land that is protecte ...

in the Yorkshire

Pennines The Pennines (), also known as the Pennine Chain or Pennine Hills, are a range of highland, uplands mainly located in Northern England. Commonly described as the "Vertebral column, backbone of England" because of its length and position, the ra ...

. It lies approximately north-west of

Bradford Bradford is a city status in the United Kingdom, city in West Yorkshire, England. It became a municipal borough in 1847, received a city charter in 1897 and, since the Local Government Act 1972, 1974 reform, the city status in the United Kingdo ...

and about north of the nearest settlement, Malham. At above sea level it is sometimes, but erroneously, considered the highest lake in England, but there are lakes at higher altitudes such as

Innominate Tarn Innominate Tarn is a small tarn in the north of the Lake District National Park in England. It is situated at 520 metres above sea level, near the summit of Haystacks. The word ''Innominate'' means ''"without a name"''. It was formerly know ...

. It is, however, the highest

marl Marl is an earthy material rich in carbonate minerals, Clay minerals, clays, and silt. When Lithification, hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae. M ...

lake in Great Britain. The lake is one of only eight upland

alkali In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The a ...

ne lakes in Europe, having a pH between 8.0 and 8.6. The

catchment area A catchment area in human geography, is the area from which a location, such as a city, service or institution, attracts a population that uses its services and economic opportunities. Catchment areas may be defined based on from where people are ...

of the lake is and the main inflow is a stream at the lake's north-west corner. The lake is at its deepest, with an average depth of and the surface area is . It takes approximately 11 weeks for water to leave the lake after it has entered. The primary outflow is a small stream at the southern end of the lake. The outflow stream goes underground after approximately before emerging downstream of

Malham Cove Malham Cove is a large curved limestone formation north of the village of Malham, North Yorkshire, England. It was formed by a waterfall carrying meltwater from glaciers at the end of the last Last glacial period, Ice Age more than 12,000 year ...

as a source of the

River Aire The River Aire is a major river in Yorkshire, England, in length. Part of the river below Leeds is canalised, and is known as the Aire and Calder Navigation. The ''Handbook for Leeds and Airedale'' (1890) notes that the distance from Malha ...

Climate

The highest recorded temperature at Malham Tarn was 28.6°C on 24 July 2019.

Natural history

Situated in a

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

area, Malham Tarn itself mainly lies on a bed of

silurian The Silurian ( ) is a geologic period and system spanning 23.5 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the third and shortest period of t ...

slate Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic ro ...

which is covered with

deposits. The lake's basin was dammed by a

moraine A moraine is any accumulation of unconsolidated debris (regolith and Rock (geology), rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a gla ...

at the end of the last glacial period, approximately years ago. It used to be about twice its current size, having shrunk due to silting at the western shore; this has formed a

bog A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and musk ...

gy region called Tarn Moss. Following

deforestation Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...

during the

Iron Age The Iron Age () is the final epoch of the three historical Metal Ages, after the Chalcolithic and Bronze Age. It has also been considered as the final age of the three-age division starting with prehistory (before recorded history) and progre ...

, the land surrounding the lake has been used for grazing which has prevented further tree growth. An embankment and sluice gate were added to the lake in 1791 by Lord Ribblesdale; this has had the effect of raising the level of the lake by approximately . The average annual rainfall over the catchment area is . The lake is home to six species of fish, as well as white-clawed crayfish,

great crested grebe The great crested grebe (''Podiceps cristatus'') is a member of the grebe family of water birds. The bird is characterised by its distinctive appearance, featuring striking black, orange-brown, and white plumage, and elaborate courtship displa ...

s, moorhens, coots,

tufted duck The tufted duck (or tufted pochard) (''Aythya fuligula'') is a small diving duck with a population of nearly one million birds, found in northern Eurasia. They are partially migratory. The scientific name is derived from Ancient Greek , an unide ...

s and teal. A number of

wader 245px, A flock of Red_knot.html" ;"title="Dunlins and Red knot">Dunlins and Red knots Waders or shorebirds are birds of the order Charadriiformes commonly found wikt:wade#Etymology 1, wading along shorelines and mudflats in order to foraging, ...

s such as redshanks, curlews,

lapwings Lapwings (subfamily Vanellinae) are any of various ground-nesting birds (Family (biology), family Charadriidae) akin to plovers and dotterels. They range from in length, and are noted for their slow, irregular wingbeats in flight and a shrill, ...

and oystercatchers breed in the surrounding area. Two rare

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from the Ancient Greek word (), meaning "the depths". ...

copepod Copepods (; meaning 'oar-feet') are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (living in the water column), some are benthos, benthic (living on the sedimen ...

s, ''Bryocamptus rhaeticus'' and ''Moraria mrazeki'', are found in the lake, along with 22 species of

molluscs Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

—nine of which are found at their highest altitude in Britain. The lake also contains a number of submerged

aquatic plant Aquatic plants, also referred to as hydrophytes, are vascular plants and Non-vascular plant, non-vascular plants that have adapted to live in aquatic ecosystem, aquatic environments (marine ecosystem, saltwater or freshwater ecosystem, freshwater ...

s, while the surrounding area is home to a diverse number of plants including wild cranberry, bearberry, crowberry, dark-leaved willow and purple moor grass. Last seen fifty years ago, captive-bred water voles (''Arvicola amphibius'') were reintroduced in August 2016. This is the highest reintroduction of water vole in the UK. The lake is located in the Malham and Arncliffe

Site of Special Scientific Interest A Site of Special Scientific Interest (SSSI) in Great Britain, or an Area of Special Scientific Interest (ASSI) in the Isle of Man and Northern Ireland, is a conservation designation denoting a protected area in the United Kingdom and Isle ...

which was established in 1955. In 1992, the lake and its wetlands were designated as a national nature reserve. The lake was listed as a

Ramsar Convention The Ramsar Convention on Wetlands of International Importance Especially as Waterfowl Habitat is an international treaty for the conservation and sustainable use of Ramsar site, Ramsar sites (wetlands). It is also known as the Convention on We ...

site in 1993. It is also in the Craven Limestone Complex

Special Area of Conservation A special area of conservation (SAC) is defined in the European Union's Habitats Directive (92/43/EEC), also known as the ''Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora''. They are to protect the 220 habitats and ap ...

History

There has been human activity at Malham Tarn dating back to the

Mesolithic The Mesolithic (Ancient Greek language, Greek: μέσος, ''mesos'' 'middle' + λίθος, ''lithos'' 'stone') or Middle Stone Age is the Old World archaeological period between the Upper Paleolithic and the Neolithic. The term Epipaleolithic i ...

era when the shores of the lake were used for camping during hunting trips for deer and wild cattle. During the

Bronze Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals (including aluminium, manganese, nickel, or zinc) and sometimes non-metals (such as phosphorus) or metalloid ...

and

s, the surrounding area was settled by farmers who used the land for grazing. Following the

Roman conquest of Britain The Roman conquest of Britain was the Roman Empire's conquest of most of the island of Great Britain, Britain, which was inhabited by the Celtic Britons. It began in earnest in AD 43 under Emperor Claudius, and was largely completed in the ...

the upland areas were not seen as attractive and the only Roman presence in the area was a marching camp on Malham Moor. During the

Medieval In the history of Europe, the Middle Ages or medieval period lasted approximately from the 5th to the late 15th centuries, similarly to the post-classical period of World history (field), global history. It began with the fall of the West ...

period the lands were owned by the

Monasteries A monastery is a building or complex of buildings comprising the domestic quarters and workplaces of monastics, monks or nuns, whether living in communities or alone ( hermits). A monastery generally includes a place reserved for prayer which m ...

, and their use for grazing continued. A survey undertaken in 1539 at the time of the dissolution of

Fountains Abbey Fountains Abbey is one of the largest and best preserved ruined Cistercians, Cistercian monasteries in England. It is located approximately south-west of Ripon in North Yorkshire, near the village of Aldfield. Founded in 1132, the abbey operat ...

makes note of a farmstead on the northern shore of the lake. Following the dissolution of the monasteries, the estates of Malham Moor then changed hands several times until they were eventually acquired by Thomas Lister—later to become the first Lord Ribblesdale—in the mid- to late-18th century. Lister then built a hunting lodge on the site of the old farm in the 1780s. The estate was then sold to businessman James Morrison in 1852. Following Morrison's death the estates were inherited by his son, Walter, in 1857. While visiting Walter Morrison in 1858, author

was inspired to write the

Victorian era In the history of the United Kingdom and the British Empire, the Victorian era was the reign of Queen Victoria, from 20 June 1837 until her death on 22 January 1901. Slightly different definitions are sometimes used. The era followed the ...

novel '' The Water-Babies, A Fairy Tale for a Land Baby''. Walter Morrison died in 1921 and the estate subsequently changed hands a number of times before being broken up. The house and the lake were eventually bought by Walter Morrison's great-niece, Mrs Hutton-Croft, in 1928. In 1946 Mrs Hutton-Croft presented the house to the

, who manage the property and previously leased the house to the

. The Field Studies Council vacated Malham Tarn House in 2023 and the house is now back under the sole occupancy of the National Trust. The house exterior and the surrounding countryside can be seen in the 1951 film '' Another Man's Poison''. In late 2023, the National Trust refurbished the North Wing buildings to the rear of Malham Tarn House, which are now occupied by the Trust's Yorkshire Dales staff and volunteers. The site also serves as a base for the National Trust's team of Rangers, as well as staff working on the 'Heart of the Dales' Landscape Recovery scheme.

References

External links

Malham-Arncliffe SSSIMalham Tarn and Moor National TrustMalham Tarn Field Centre
{{authority control Glacial lakes Lakes of North Yorkshire National nature reserves in England Malham Ramsar sites in England Sites of Special Scientific Interest in North Yorkshire Sites of Special Scientific Interest notified in 1955 River Aire Malham