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, ...

near the village of

Malham Malham is a village and civil parish in the Craven district of North Yorkshire, England. Before 20th century boundary changes, the village was part of the Settle Rural District, in the historic West Riding of Yorkshire. In the ''Domesday Book' ...

in the

Yorkshire Dales The Yorkshire Dales is an upland area of the Pennines in the historic county of Yorkshire, England, most of it in the Yorkshire Dales National Park created in 1954. The Dales comprise river valleys and the hills rising from the Vale of York w ...

, 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 A marl lake is a type of alkaline lake whose bottom sediments include large deposits of marl, a mixture of clay and carbonate minerals. The term is particularly applied to lakes that have been dredged or mined for marl, often for manufacturing ...

in the United Kingdom. Its

geology Geology () is a branch of natural science concerned with Earth and other Astronomical object, astronomical objects, the features or rock (geology), rocks of which it is composed, and the processes by which they change over time. Modern geology ...

flora Flora is all the plant life present in a particular region or time, generally the naturally occurring ( indigenous) native plants. Sometimes bacteria and fungi are also referred to as flora, as in the terms '' gut flora'' or '' skin flora''. ...

and

fauna Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is '' flora'', and for fungi, it is '' funga''. Flora, fauna, funga and other forms of life are collectively referred to as '' biota''. ...

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

National Trust The National Trust, formally the National Trust for Places of Historic Interest or Natural Beauty, is a charity and membership organisation for heritage conservation in England, Wales and Northern Ireland. In Scotland, there is a separate and ...

, 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 It was established as the Council for the Promotion of Field Studies in 1943 with the ...

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 worki ...

'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 natural park in use for conservation purposes, created and protected by national governments. Often it is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns. Although individual ...

in the Yorkshire

Pennines The Pennines (), also known as the Pennine Chain or Pennine Hills, are a range of uplands running between three regions of Northern England: North West England on the west, North East England and Yorkshire and the Humber on the east. Common ...

. It lies approximately north-west of

Bradford Bradford is a city and the administrative centre of the City of Bradford district in West Yorkshire, England. The city is in the Pennines' eastern foothills on the banks of the Bradford Beck. Bradford had a population of 349,561 at the 2011 ...

and about north of the nearest settlement,

. 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. It is, however, the highest

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

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

alkali In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic 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 ...

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

catchment area In human geography, a catchment area 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 Ice Age more than 12,000 years ago. Today it is a ...

as a

source Source may refer to: Research * Historical document * Historical source * Source (intelligence) or sub source, typically a confidential provider of non open-source intelligence * Source (journalism), a person, publication, publishing institute o ...

of the

River Aire The River Aire is a major river in Yorkshire, England, in length. The ''Handbook for Leeds and Airedale'' (1890) notes that the distance from Malham to Howden is direct, but the river's meanderings extend that to . Between Malham Tarn and Ai ...

Climate

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

Natural history

Situated in a

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms w ...

area, Malham Tarn itself mainly lies on a bed of

silurian The Silurian ( ) is a geologic period and system spanning 24.6 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 shortest period of the Paleoz ...

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 rock. ...

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), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice sh ...

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 Siltation, is water pollution caused by particulate terrestrial clastic material, with a particle size dominated by silt or clay. It refers both to the increased concentration of suspended sediments and to the increased accumulation (temporary or ...

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 muskeg; a ...

gy region called Tarn Moss. Following

deforestation Deforestation or forest clearance is the removal 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. The most concentrated ...

during the

Iron Age The Iron Age is the final epoch of the three-age division of the prehistory and protohistory of humanity. It was preceded by the Stone Age ( Paleolithic, Mesolithic, Neolithic) and the Bronze Age ( Chalcolithic). The concept has been mostly ...

, 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 ''Austropotamobius pallipes'' is an endangered European freshwater crayfish, and the only crayfish native to the British Isles. Its common names include white-clawed crayfish and Atlantic stream crayfish. Distribution It is found from the east ...

great crested grebe The great crested grebe (''Podiceps cristatus'') is a member of the grebe family of water birds noted for its elaborate mating display. Taxonomy The great crested grebe was formally described by the Swedish naturalist Carl Linnaeus in 1758 in t ...

s, moorhens,

coots Coots are medium-sized water birds that are members of the rail family, Rallidae. They constitute the genus ''Fulica'', the name being the Latin term for "coot". Coots have predominantly black plumage, and—unlike many rails—they are usually ...

, tufted ducks and

teal alt=American teal duck (male), Green-winged teal (male) Teal is a greenish-blue colour. Its name comes from that of a bird — the Eurasian teal (''Anas crecca'') — which presents a similarly coloured stripe on its head. The word is oft ...

. A number of

wader 245px, A flock of Dunlins and Red knots">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 mudflat ...

s such as redshanks,

curlews The curlews () are a group of nine species of birds in the genus ''Numenius'', characterised by their long, slender, downcurved bills and mottled brown plumage. The English name is imitative of the Eurasian curlew's call, but may have been i ...

, lapwings and

oystercatchers The oystercatchers are a group of waders forming the family Haematopodidae, which has a single genus, ''Haematopus''. They are found on coasts worldwide apart from the polar regions and some tropical regions of Africa and South East Asia. The e ...

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 ancient Greek, βένθος (bénthos), meaning " ...

copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Some species are planktonic (inhabiting sea waters), some are benthic (living on the ocean floor), a number of species have ...

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

molluscs Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estim ...

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

aquatic plant Aquatic plants are plants that have adapted to living in aquatic environments ( saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that ...

s, while the surrounding area is home to a diverse number of plants including wild cranberry,

bearberry Bearberries ( indigenous kinnickinnick) are three species of dwarf shrubs in the genus ''Arctostaphylos''. Unlike the other species of ''Arctostaphylos'' (see manzanita), they are adapted to Arctic and Subarctic climates, and have a circumpolar ...

crowberry ''Empetrum nigrum'', crowberry, black crowberry, or, in western Alaska, blackberry, is a flowering plant species in the heather family Ericaceae with a near circumboreal distribution in the Northern Hemisphere. It is usually dioecious, but ther ...

dark-leaved willow ''Salix myrsinifolia'', known as the dark-leaved willow or myrsine-leaved willow, is a species of willow native to Europe and Western Siberia. It forms a high shrub. In the north it often becomes a tree up to tall.Väre H., Kiuru H., ''Suomen ...

and

purple moor grass ''Molinia caerulea'', known by the common name purple moor-grass, is a species of grass that is native to Europe, west Asia, and north Africa. It grows in locations from the lowlands up to in the Alps. Like most grasses, it grows best in acid so ...

. 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 sites (wetlands). It is also known as the Convention on Wetlands. It ...

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 a ...

History

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

Mesolithic The Mesolithic ( 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 is often used synonymo ...

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 metalloids suc ...

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 refers to the conquest of the island of Britain by occupying Roman forces. It began in earnest in AD 43 under Emperor Claudius, and was largely completed in the southern half of Britain by 87 when the Stan ...

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 late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire a ...

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 ...

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

dissolution Dissolution may refer to: Arts and entertainment Books * ''Dissolution'' (''Forgotten Realms'' novel), a 2002 fantasy novel by Richard Lee Byers * ''Dissolution'' (Sansom novel), a 2003 historical novel by C. J. Sansom Music * Dissolution, in mu ...

Fountains Abbey Fountains Abbey is one of the largest and best preserved ruined Cistercian monasteries in England. It is located approximately south-west of Ripon in North Yorkshire, near to the village of Aldfield. Founded in 1132, the abbey operated for 40 ...

makes note of a farmstead on the northern shore of the lake. Following the dissolution of the monasteries, the estates of

Malham Moor Malham Moor is a civil parish in the Craven District, Craven district of North Yorkshire, England. Its population was estimated at 70 in 2015. It has a joint Parish councils in England, parish council, Kirkby Malhamdale Parish Council, with ...

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 period of Queen Victoria's reign, from 20 June 1837 until her death on 22 January 1901. The era followed the Georgian period and preceded the Edwa ...

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 lease the house to the

, now called the Malham Tarn Field Studies Centre. The house exterior and the surrounding countryside can be seen in the 1951 film ''

Another Man's Poison ''Another Man's Poison'' is a 1951 British drama film directed by Irving Rapper and starring Bette Davis, Gary Merrill and Emlyn Williams. The screenplay by Val Guest is based on the play ''Deadlock'' by Leslie Sands. Plot Successful mystery no ...

''.

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

Ramsar sites in England Sites of Special Scientific Interest in North Yorkshire Sites of Special Scientific Interest notified in 1955