[2][3][4] It has been called Ireland's amazing disappearing lake,[2] due to the way it empties quickly - in as little as two days - and unpredictably, sometimes killing thousands of fish.
[5] Lough Funshinagh is one of a number of seasonal lakes, or turlough, found in the karst areas of Ireland, west of the River Shannon.
[14] The area at Lough Funshinagh is part of the ‘Athlone chain’ of eskers in the System of Clara, as described in the 1876 Scientific transactions of the Royal Dublin Society.
“While Lough Funshinagh is designated as a turlough due to its characteristic fluctuating water levels, it is extremely slow to drain and seldomly empties completely.
The characteristic slow response of Funshinagh means that, unlike other turloughs in Ireland, it does not get the opportunity to reset it’s flood pattern each year.
[18] However, it was noted by Drew and Burke in a Geological Survey Ireland publication in 1996 that: "It does not seem as though a plug hole in the sink ruptured as Coleman (op cit.)
[19] In February 2021, Roscommon County Council agreed "that an overflow pipe be installed in Lough Funshinagh and that the planning application be fast tracked to commence the project as soon as possible.
In March 2022 plans to drain the lake by constructing a 2.5-mile (4 km) pipeline to Lough Ree were halted when the Friends of the Irish Environment obtained an injunction, halting the work on the grounds that no environmental impact assessment had been carried out before commencing works to this SAC (required legally under the EU Habitats Directive), to assess impacts to the Lough and to the area to which the water would be relocated.
[26][27] It is noted on the FloodInfo website that: "Roscommon County Council are leading the response to the flooding risk at Lough Funshinagh.
Following a High Court Order in March 2022 remediation works in line with the Reinstatement Plan for Lough Funshinagh were undertaken and completed.
Roscommon County Council, that is leading the project, has established an Expert Working Group to support and help to identify the pathway to finding a means of progressing a viable solution.
[6] Geological Survey Ireland note that in spring 2024, the water levels monitored at Lough Funshinagh reached over 69 mAOD.
[32][33][34] On 10 January 2025, it was announced that Roscommon County Council’s application for a 3 km temporary underground overflow pipeline to pump water from Lough Funshinagh to the Cross River was granted, with some conditions attached.
[21] One of the features qualifying this site for SAC status includes specific vegetation – this is the ‘rivers with muddy banks with Chenopodion rubri p.p.
At the edges of the lake, wet grassland occurs, including Creeping Bent (Agrostis stolonifera), Marsh Pennywort (Hydrocotyle vulgaris) and Silverweed (Potentilla anserina).
Also found at the site are Various-leaved Pondweed (Potamogeton gramineus), Amphibious Bistort (Polygonum amphibium), and Marsh Cudweed (Gnaphalium uliginosum).
The moss Fontinalis antipyretica occurs here, as does the rare Northern Yellow-cress (Rorippa islandica), a species listed in the Irish Red Data Book.
[11] The NPWS site synopsis also notes the presence of Bewick's Swan (Cygnus bewickii), Gadwall and Pintail, and mentions that the Greenland White-Fronted Geese occurring here are the River Suck flock of this species.
The statutory instrument specifies a list of 31 actions which require the permission of the Minister before they may be carried out at the site, including, for example, stocking or re-stocking with fish, changing of agricultural use from hay meadow to any other use, works on, or alterations to, the banks, bed or flow of a drain, watercourse or waterbody, drainage works including digging, deepening, widening or blocking a drain, watercourse or waterbody or water abstraction, sinking of boreholes and wells.
[9] According to records from the Dúchas School’s Collection, there had been a castle at Ballagh Island at Lough Funshinagh, which belonged to the O’Kelly family.