Lough Derg, historically Lough Dergart ( ga, Loch Deirgeirt), is a freshwater

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

in the

Shannon River Basin The Shannon River Basin consists of the area containing Ireland's longest river, the River Shannon, and all of its tributaries and lakes. The official Ordnance Survey Ireland length of the Shannon from its Shannon Pot source is made up of tid ...

, 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 in the island of Ireland, the United Kingdom and the British Isles. It has a surface area of and supplies 40% of Northern Ireland's water. Its main inflows come ...

and

Lough Corrib Lough Corrib ( ; ) is a lake in the west of Ireland. The River Corrib or Galway River connects the lake to the sea at Galway. It is the largest lake within the Republic of Ireland and the second largest on the island of Ireland (after Lough Nea ...

). It is a long, narrow lake, with shores in counties Clare (south-west),

Galway Galway ( ; ga, Gaillimh, ) is a City status in Ireland, city in the West Region, Ireland, West of Ireland, in the Provinces of Ireland, province of Connacht, which is the county town of County Galway. It lies on the River Corrib between Lo ...

(north-west), and

Tipperary Tipperary is the name of: Places *County Tipperary, a county in Ireland **North Tipperary, a former administrative county based in Nenagh **South Tipperary, a former administrative county based in Clonmel *Tipperary (town), County Tipperary's na ...

(to the east). It is the southernmost of three large lakes on the

River Shannon The River Shannon ( ga, Abhainn na Sionainne, ', '), at in length, is the longest river in the British Isles. It drains the Shannon River Basin, which has an area of , – approximately one fifth of the area of the island of Ireland. The Shan ...

; the others being

Lough Ree Lough Ree () is a lake in the midlands of Ireland, the second of the three major lakes on the River Shannon. Lough Ree is the second largest lake on the Shannon after Lough Derg. The other two major lakes are Lough Allen to the north, and Lou ...

and

Lough Allen Lough Allen () is a lake on the River Shannon in northeastern Connacht, Ireland. Most of the lake is in County Leitrim, with a smaller part in County Roscommon. The lake lies to the south of the River Shannon's source, near the Iron Mountains, ...

. Towns and villages on Lough Derg include

Portumna Portumna ( - meaning 'the landing place of the oak') is a market town in the south-east of County Galway, Ireland, on the border with and linked by a bridge to County Tipperary. The town is located to the west of the point where the River Shanno ...

, Killaloe & Ballina,

Dromineer Dromineer The earliest form of the name dating from 1302 was Dromynwyr 4() is a small village and townland in County Tipperary, Ireland. It is situated on the shores of Lough Derg on the River Shannon. The village is located 10 km north ...

Terryglass Terryglass () is a village in County Tipperary, Ireland. The small town is located on the R493 regional road on the north-eastern shore of Lough Derg near where the River Shannon enters the Lough. It is a civil parish in the historical barony ...

Mountshannon Mountshannon (, historically anglicised as ''Ballybolan'') is a village in east County Clare, Ireland. It is part of the Catholic parish Mountshannon-Whitegate. The village is on the western shore of Lough Derg, north of Killaloe. Mountshannon ...

and Garrykennedy. The lake's name evolved from the Irish ''Loch Deirgdheirc''. This was one of the names of

The Dagda The Dagda (Old Irish: ''In Dagda,'' ga, An Daghdha, ) is an important god in Irish mythology. One of the Tuatha Dé Danann, the Dagda is portrayed as a father-figure, king, and druid.Koch, John T. ''Celtic Culture: A Historical Encyclopedia ...

, an Irish god, and literally means "red eye".

Geography

At its deepest, the lake is 36 metres deep and covers an

area Area is the quantity that expresses the extent of a region on the plane or on a curved surface. The area of a plane region or ''plane area'' refers to the area of a shape A shape or figure is a graphics, graphical representation of an obje ...

of 130 km² (50.2 sq miles). 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 generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined and ...

plant at

Ardnacrusha Ardnacrusha ( ga, Ard na Croise) is a village in County Clare, Munster, Ireland, located on the northern bank of the River Shannon. By road, it is north of Limerick. The name derives from the phrase ''Ard na Croise'' meaning "the height of t ...

, 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 ( ; ga, Luimneach ) is a western city in Ireland situated within County Limerick. It is in the province of Munster and is located in the Mid-West which comprises part of the Southern Region. With a population of 94,192 at the 2016 ...

Dublin Dublin (; , or ) is the capital and largest city of Republic of Ireland, Ireland. On a bay at the mouth of the River Liffey, it is in the Provinces of Ireland, province of Leinster, bordered on the south by the Dublin Mountains, a part of th ...

through the canals in the midlands of Ireland. Navigable over its full 40 km length, Lough Derg is today popular with cruisers and other

pleasure craft Boating is the leisurely activity of travelling by boat, or the recreational use of a boat whether Motorboat, powerboats, Sailing, sailboats, or man-powered vessels (such as rowing and paddle boats), focused on the travel itself, as well as sp ...

, 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, windsurfer, or kitesurfer), on ''ice'' (iceboat) or on ''land'' (land yacht) over a chosen cour ...

and

fishing Fishing is the activity of trying to catch fish. Fish are often caught as wildlife from the natural environment, but may also be caught from stocked bodies of water such as ponds, canals, park wetlands and reservoirs. Fishing techniques inclu ...

. The

University of Limerick The University of Limerick (UL) ( ga, Ollscoil Luimnigh) 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 beca ...

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

canoe A canoe is a lightweight narrow 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 a single-bladed paddle. In British English, the term ...

kayak A kayak is a small, narrow watercraft which is typically propelled by means of a double-bladed paddle. The word kayak originates from the Greenlandic word ''qajaq'' (). The traditional kayak has a covered deck and one or more cockpits, each se ...

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 aerospace and surf culture of California. Windsurfing ga ...

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

RNLI The Royal National Lifeboat Institution (RNLI) is the largest charity that saves lives at sea around the coasts of the United Kingdom, the Republic of Ireland, the Channel Islands, and the Isle of Man, as well as on some inland waterways. It i ...

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 ( ga, Comhairle Cathrach Bhaile Átha Cliath) is the authority responsible for local government in the city of Dublin in Ireland. As a city council, it is governed by the Local Government Act 2001. Until 2001, the council wa ...

published a plan in 2011 for a

pipeline Pipeline may refer to: Electronics, computers and computing * Pipeline (computing), a chain of data-processing stages or a CPU optimization found on ** Instruction pipelining, a technique for implementing instruction-level parallelism within a s ...

to supply up to 350 million litres of water a day from Lough Derg to Dublin city and region. In 2016 the

Parteen Parteen () is a village in County Clare, Ireland. It is situated in the townland of the same name that is part of the civil parish of St Patrick's. It is also part of an Ecclesiastical parish of "Parteen-Meelick" in the Roman Catholic Diocese o ...

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 Knockanacree (''Cnocán an Chraoi'' in Irish language, Irish) is a townland in the historical Barony (Ireland), Barony of Ormond Lower, County Tipperary, Republic of Ireland, Ireland. The townland is located within the civil parish of Modreeny nor ...

near

Cloughjordan Cloughjordan, officially Cloghjordan ( , ), is a town in County Tipperary in Ireland. It is in the barony of Ormond Lower, and it is also a parish in the Roman Catholic Diocese of Killaloe. The town is situated in the north-western part of T ...

in County Tipperary and gravity fed from there to Dublin.

Ecology

A breeding pair of

white-tailed eagle The white-tailed eagle (''Haliaeetus albicilla'') is a very large species of sea eagle widely distributed across temperate Palearctic, Eurasia. Like all eagles, it is a member of the family Accipitridae (or accipitrids) which includes other diur ...

s 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 Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mi ...

in the family Characeae (stoneworts), was first recorded in Ireland in this lough in 2016. In 2021, invasive

quagga mussel The quagga mussel (''Dreissena rostriformis'', also known as ''Dreissena bugensis'' or ''Dreissena rostriformis bugensis'') is a species (or subspecies) of freshwater mussel, an aquatic bivalve mollusk in the family Dreissenidae. It has an aver ...

s 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 *

* Garrykennedy *

Kilgarvan Kilgarvan () is a small village in County Kerry, Ireland. It is situated on the banks of the Roughty River which flows into Kenmare Bay. By car, the village is a ten-minute trip from Kenmare, and thirty minutes from Killarney. History Kilgarva ...

* Killaloe *

Portroe Portroe () is a village in County Tipperary, Ireland. The village is located on the R494 regional road, 3 km from the eastern shore of Lough Derg and 10 km west of the town of Nenagh. Portroe spans the townlands of Garrykennedy, Glenc ...

Scarriff Scarriff Central Statistics Office, Census 2002Population of Towns ordered by County and size, 1996 and 2002 or Scariff () is a large village in east County Clare, Ireland, situated in the midwest of Ireland. The town is on the West end of Loug ...

(location of regional

Waterways Ireland Waterways Ireland ( ga, Uiscebhealaí Éireann; Ulster-Scots: ''Watterweys Airlann'') is one of the six all-Ireland North/South implementation bodies established under the Belfast Agreement in 1999. It is responsible for the management, mainten ...

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