Lough Derg, historically Lough Dergart (), is a freshwater

lake A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...

in the Shannon River Basin, Ireland. It is the third-biggest on the island of Ireland (after

Lough Neagh Lough Neagh ( ; ) is a freshwater lake in Northern Ireland and is the largest lake on the island of Ireland and in the British Isles. It has a surface area of and is about long and wide. According to Northern Ireland Water, it supplies 4 ...

and Lough Corrib) and the second largest lake in the Republic of Ireland. It is a long, narrow lake, with shores in counties Clare (south-west),

Galway Galway ( ; , ) is a City status in Ireland, city in (and the county town of) County Galway. It lies on the River Corrib between Lough Corrib and Galway Bay. It is the most populous settlement in the province of Connacht, the List of settleme ...

(north-west), and Tipperary (to the east). It is the southernmost of three large lakes on the River Shannon; the others being

Lough Ree Lough Ree (), translated to English as ''King's Lake'' or ''King Lake'', is a lake in the midlands of Republic of Ireland, Ireland, the second of the three major lakes on the River Shannon. Lough Ree is the second largest lake on the Shannon af ...

and Lough Allen. Towns and villages on Lough Derg include Portumna, Killaloe & Ballina, Dromineer,

Terryglass Terryglass () is a village in County Tipperary, Republic of Ireland, Ireland. It is on the north-eastern shore of Lough Derg (Shannon), Lough Derg, near where the River Shannon enters the lough, on the R493 road. Terryglass is also a civil parish ...

, Mountshannon and Garrykennedy. The lake's name evolved from the Irish ''Loch Deirgdheirc''. This was one of the names of The Dagda, the father of gods and men in

Irish mythology Irish mythology is the body of myths indigenous to the island of Ireland. It was originally Oral tradition, passed down orally in the Prehistoric Ireland, prehistoric era. In the History of Ireland (795–1169), early medieval era, myths were ...

, and literally means "red eye". Lough Derg has many islands including Inis Cealtra or Holy Island.

Geography

At its deepest, the lake is deep and covers an

area Area is the measure of a region's size on a surface. The area of a plane region or ''plane area'' refers to the area of a shape or planar lamina, while '' surface area'' refers to the area of an open surface or the boundary of a three-di ...

of . Close downstream from where Lough Derg empties into the Shannon are the falls of Doonass, the largest fall on the otherwise gently sloping river. Nearby is the location of the

hydroelectric power Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

plant at Ardnacrusha, which, when built in 1927 was the world's largest.

Usage

In the nineteenth century, Lough Derg was an important artery from the port at

Limerick Limerick ( ; ) is a city in western Ireland, in County Limerick. It is in the Provinces of Ireland, province of Munster and is in the Mid-West Region, Ireland, Mid-West which comprises part of the Southern Region, Ireland, Southern Region. W ...

Dublin Dublin is the capital and largest city of Republic of Ireland, Ireland. Situated on Dublin Bay at the mouth of the River Liffey, it is in the Provinces of Ireland, province of Leinster, and is bordered on the south by the Dublin Mountains, pa ...

through the canals in the midlands of Ireland. Navigable over its full length, Lough Derg is today popular with cruisers and other pleasure craft, as well as

sailing Sailing employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the ''water'' (sailing ship, sailboat, raft, Windsurfing, windsurfer, or Kitesurfing, kitesurfer), on ''ice'' (iceboat) or on ''land'' (Land sa ...

and

fishing Fishing is the activity of trying to catch fish. Fish are often caught as wildlife from the natural environment (Freshwater ecosystem, freshwater or Marine ecosystem, marine), but may also be caught from Fish stocking, stocked Body of water, ...

. The

University of Limerick University of Limerick (UL) () is a Public university, public research university institution in Limerick, Republic of Ireland, Ireland. Founded in 1972, as the National Institute for Higher Education, Limerick, it became a university in Septemb ...

has an activity centre by the lake, just north of Killaloe, where there are

canoe A canoe is a lightweight, narrow watercraft, water vessel, typically pointed at both ends and open on top, propelled by one or more seated or kneeling paddlers facing the direction of travel and using paddles. In British English, the term ' ...

kayak ] A kayak is a small, narrow human-powered watercraft typically propelled by means of a long, double-bladed paddle. The word ''kayak'' originates from the Inuktitut word '' qajaq'' (). In British English, the kayak is also considered to be ...

windsurfing Windsurfing is a wind-propelled water sport that is a combination of sailing and surfing. It is also referred to as "sailboarding" and "boardsailing", and emerged in the late 1960s from the Californian aerospace and surf culture. Windsurfing gain ...

, sailing dingies, and other recreations. Lough Derg is home to an

RNLI The Royal National Lifeboat Institution (RNLI) is the largest of the lifeboat services operating around the coasts of the United Kingdom, Ireland, the Channel Islands, and the Isle of Man, as well as on some inland waterways. Founded in 1824 ...

Lifeboat which is based at Dromineer, the first inland station in Ireland. In June 2013, 35 people were brought to safety when a major rescue effort was undertaken after an international rowing event was hit by severe weather.

Dublin City Council Dublin City Council () is the Local government in the Republic of Ireland, local authority of the city of Dublin in Republic of Ireland, Ireland. As a city council, it is governed by the Local Government Act 2001. Until 2001, the authority was k ...

published a plan in 2011 for a

pipeline A pipeline is a system of Pipe (fluid conveyance), pipes for long-distance transportation of a liquid or gas, typically to a market area for consumption. The latest data from 2014 gives a total of slightly less than of pipeline in 120 countries ...

to supply up to 350 million litres of water a day from Lough Derg to Dublin city and region. In 2016 the Parteen Basin at the south of lough was chosen as the proposed site of extraction. Water would be pumped to a break pressure tank at Knockanacree near Cloughjordan in County Tipperary and gravity fed from there to Dublin.

Ecology

A breeding pair of white-tailed eagles first nested on an island in Lough Derg in 2012. This marked a great success for the Irish reintroduction programme started in the summer of 2007. '' Nitellopsis obtusa'', an invasive alga in the family Characeae (stoneworts), was first recorded in Ireland in this lough in 2016. In 2021, invasive quagga mussels were discovered in the lake and in

by a research team from UCD. The North-East Shore is listed as a Special Area of Conservation.

Towns/villages

* Ballina * Dromineer * Garrykennedy * Kilgarvan * Killaloe * Mountshannon * Portroe * Portumna * Scarriff (location of regional Waterways Ireland office)Waterways Ireland ePortal
*

* Whitegate

References

aerial view of Lough Derg's northern shores, featuring Terryglass Drominagh and Kilgarvan Quay

Irish Examiner, 18 February 2011
Asian clams threaten Lough Derg fish stock
Dan Danaher, The Clare Champion, 21 June 2012. {{DEFAULTSORT:Derg Lakes of County Galway Lakes of County Clare River Shannon Lakes of County Tipperary

Geography

Usage

Ecology

Towns/villages

See also

References