Loch Lomond

Loch Lomond (/ˈlɒx ˈloʊmənd/; Scottish Gaelic: Loch Laomainn) is a freshwater Scottish loch which crosses the Highland Boundary Fault (HBF), often considered the boundary between the lowlands of Central Scotland and the Highlands. Traditionally forming part of the boundary between the counties of Stirlingshire and Dunbartonshire, Loch Lomond is split between the council areas of Stirling, Argyll and Bute and West Dunbartonshire. Its southern shores are about 23 kilometres (14 mi) northwest of the centre of Glasgow, Scotland's largest city. The Loch forms part of the Loch Lomond and The Trossachs National Park which was established in 2002. From a limnological perspective, Loch Lomond is classified as a dimictic lake, meaning it typically undergoes two mixing periods each year. This occurs in the spring and autumn when the water column becomes uniformly mixed due to temperature-driven density changes

Loch Lomond is 36.4 kilometres (22.6 mi) long and between one and eight kilometres (1⁄2–5 miles) wide, with a surface area of 71 km² (27.5 sq mi). It is the largest lake in Great Britain by surface area; in the United Kingdom, it is surpassed only by Lough Neagh and Lough Erne in Northern Ireland. In the British Isles as a whole there are several larger loughs in the Republic of Ireland. The loch has a maximum depth of about 190 metres (620 ft) in the deeper northern portion, although the southern part of the loch rarely exceeds 30 metres (98 ft) in depth. The total volume of Loch Lomond is 2.6 km³ (0.62 cu mi), making it the second largest lake in Great Britain, after Loch Ness, by water volume.Due to its considerable depth and latitudinal location, Loch Lomond exhibits thermal stratification during the summer months, with a distinct epilimnion, metalimnion, and hypolimnion forming in deeper areas. These stratification patterns have important implications for nutrient cycling and aquatic ecology within the loch. During periods of stratification, a decrease in hypolimnetic oxygen can occur in the deeper northern basin, which can affect the species distribution patterns.

Loch Lomond is considered oligotrophic (north of HBF) to mesotrophic (south of HBF), with relatively low to moderate nutrient levels and generally good water quality, although localised pressures such as agriculture and tourism can contribute to nutrient enrichment.

The loch contains many islands, including Inchmurrin, the largest fresh-water island in the British Isles. Loch Lomond is a popular leisure destination and is featured in the song "The Bonnie Banks o' Loch Lomond". The loch is surrounded by hills, including Ben Lomond on the eastern shore, which is 974 metres (3,196 ft) in height and the most southerly of the Scottish Munro peaks. A 2005 poll of Radio Times readers voted Loch Lomond as the sixth greatest natural wonder in Britain.