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 224 miles made up of 63.5 miles tidal water flow and 160.5 miles freshwater flow.

Statistics
The Shannon Basin is Ireland's largest basin with an area of 11700 km2. Including the estuary and the River Feale, the total catchment drains a total of 16,865 km2.

It has a Long Term Average Flow of 208.1 m3/s (at Limerick City). This is double the flow rate of Ireland's second largest river, the River Corrib (104.8 m3/s). If the discharges from all of the rivers and streams into the Shannon Estuary (including the rivers Feale 34.6 m3/s, Maigue 15.6 m3/s, Fergus 25.7 m3/s, and Deel 7.4 m3/s) are added to the discharge at Limerick, the total discharge of the River Shannon at its mouth at Loop Head reaches 300 m3/s.

The River Shannon is a traditional freshwater river for just 45% of its total length. Excluding the 63.5 miles tidal estuary from its total length of 224 miles, if one also excludes the lakes (L. Derg 24 mi, L. Ree 18 mi, L. Allen 7 mi plus L. Boderg, L. Bofin, L. Forbes, L. Corry) from the Shannon's freshwater flow of 160.5 miles, the Shannon as a freshwater river is only about 100 miles long.

The Shannon River Basin is part of the Shannon International River Basin District (SHIRBD) administrative area which has an area of 17963 km2 in area. In addition to the Shannon Basin, the district also covers coastal parts of counties Kerry and Clare which drain to the sea. The SHIRBD contains 7666 km of rivers, 1220 km of coastline including estuaries, and 113 lakes, including 53 over 50 ha in size. The main land use throughout the SHIRBD area is agriculture (70.7%). Peatlands (11.1%) and forestry (3.2%) are also important. The SHIRBD's population is 618,884 at 34 pd/km2 (Census data 2002).



Furthest sources
There are some tributaries within the River Shannon system which have headwaters that are further in length (from source to mouth) than the Shannon Pot source, such as the Owenmore River (County Cavan) in County Cavan, which flows west for 14.5 km through the valley of Glangevlin before joining the Shannon about 3 km below the Shannon Pot at Lugnashinna, thus adding 11 km to the Shannon's overall length, bringing it to 372 km.

Also the Boyle River has a similar claim. The river flow from the furthest reaches of the Boyle catchment to Limerick city has a measurement of 290 km. When added to the Shannon's 63.5 miles estuary this gives a total river flow of 392.1 km, which makes it the longest river within the River Shannon basin (from source to mouth)—31.6 km longer than the Shannon Pot source. Thus the Boyle-Shannon river can be regarded as having the longest natural river flow in Ireland.

Geography
The River Shannon Basin touches more than half (17) of Ireland's counties:- Limerick, Clare, Tipperary, Offaly, Westmeath, Longford, Roscommon, Kerry, Galway, Leitrim, Cavan, Sligo, Mayo, Cork, Laois, Meath and Fermanagh.

Towns situated in the Shannon Basin
Towns and Villages (with 2011 populations ) within the Shannon River Basin and the rivers and riverbanks on which they stand:

Shannon River: (going downstream)
 * Dowra
 * Drumshanbo (Lough Allen Canal – Left Bank) 857
 * Leitrim Village (L. Bank) 485
 * Carrick-on-Shannon 3,980
 * Jamestown (L. Bank)
 * Drumsna (L. Bank) 247
 * Drumod (Lough Boderg – L. Bank) 356
 * Roosky (Right Bank) 188
 * Termonbarry (R. Bank) 366
 * Cloondara (L. Bank)
 * Lanesborough 1,388
 * Athlone 20,153
 * Clonmacnoise (L. Bank)
 * Shannonbridge (L. Bank) 206
 * Banagher (L. Bank) 1,653
 * Portumna (R. Bank) 1,530
 * Terryglass (Lough Derg – L. Bank)
 * Mountshannon (Lough Derg – R. Bank) 152
 * Dromineer (Lough Derg – L. Bank) 113
 * Ballina (L. Bank) 2,442
 * Killaloe (R. Bank) 1,292
 * O'Briensbridge 235
 * Castleconnell (L. Bank) 1,917
 * Ardnacrusha
 * Limerick City 87,081
 * Shannon (S. Estuary – R. Bank) 9,673
 * Kilrush (S. Estuary – R. Bank) 2,695
 * Carrigaholt (S. Estuary – R. Bank)
 * Foynes (S. Estuary – L. Bank) 543
 * Glin (S. Estuary – L. Bank) 577
 * Tarbert (S. Estuary – L. Bank) 551
 * Ballylongford (S. Estuary – L. Bank) 418
 * Ballybunion (S. Estuary – L. Bank) 1,354

Shannon River tributaries

 * Boyle river: Boyle 2,588
 * Lung river: Ballaghaderreen (outskirts) 1,822
 * Camlin river: Longford 9,601
 * Hind river: Roscommon (outskirts) 5,693
 * River Inny (Leinster): Mullingar 20,103
 * River Brosna: Ballymahon 1,563, Ferbane 1,165, Tullamore (Tullamore river) 14,361
 * River Suck: Castlerea 1,985, Athleague 241, Ballinasloe 6,577
 * Little Brosna river: Birr 5,452
 * Ballyfinboy River: Borrisokane 1,145, Cloughjordan 511
 * Nenagh river: Nenagh 8,439
 * River Graney: Scariff 798
 * Ratty river, also named Owengarney River or O'Garney River, : Sixmilebridge 1,839, Bunratty 219
 * River Fergus: Ennis 25,360, Newmarket-on-Fergus 1,773
 * River Maigue: Adare 1,106
 * River Deel: Rathkeale 1,550, Askeaton 1,149
 * River Feale: Listowel 4,338, Abbeyfeale 2,007

Tributary Sub Catchments


Freshwater Catchments (With Areas – km2) Going downstream

Left Bank:


 * L Allen (upstream from L. Allen outlet) 415 km2
 * Eslin River 73 km2
 * River Rinn 311 km2
 * Camlin River 352 km2
 * River Inny (Leinster) 1,254 km2
 * River Brosna 1,248 km2
 * Little Brosna River 662 km2
 * Ballyfinboy River 182 km2
 * Nenagh River 321 km2
 * Mulkear River 660 km2

Right Bank:


 * Boyle River 725 km2
 * Hind River 78 km2
 * River Suck 1,600 km2
 * Cappagh/Kilcrow 414 km2
 * River Graney 295 km2

Estuarine Catchments Areas

Left Bank:


 * River Maigue 1,0002
 * River Deel 426 km2
 * River Feale 1,170 km2

Right Bank:


 * Bunratty River 233 km2
 * River Fergus 1,043 km2

There are many other smaller tributaries which join the Shannon along its journey.

Lakes
There are a multitude of lakes within the Shannon River Basin, both on the main river and throughout the sub-catchments.

Here is a table showing the major lakes: