Administration
Waterways Ireland, a cross-border organisation, established under the Belfast Agreement 1999, is responsible for navigation on the Erne System, as well the island of Ireland's other navigable waterways.
Rivers Agency, an executive agency within Northern Ireland's Department of Agriculture and Rural Affairs, retains ownership of the bed and foreshore and manages water levels within the ranges specified in the Erne Drainage and Development Act (1950). The drainage scheme was designed by Percy Shepherd. Water level control is undertaken in conjunction with the Electricity Supply Board (ESB) in the Republic of Ireland under the terms of an agreement made in 1950 when the River Erne was harnessed for hydroelectric power generation. The agreement requires that levels are maintained in the Upper Lough between 150 ft. and 154 ft. (Apr. – Sept.) / 155 ft. (Oct. – Mar.), and in the Lower Lough between 147 ft. and 152 ft. These levels relate to the Irish grid datum at Poolbeg Lighthouse and is in imperial measurements of feet.
Water levels in Upper and Lower Lough Erne are managed by a control structures located at Portora in Enniskillen and by the hydro electric power station at Cliff between Belleek and Ballyshannon, in the Republic of Ireland. During the summer period it is aimed to keep the water level at the down steam side of Portora, at or above, 150 ft. to avoid the need for the gates to be closed requiring the use of the navigation lock. This is to prevent restriction to boat traffic using the navigation facilities at the peak tourist period.
Rapid draw down of water levels in the Upper Lough is prevented by the restricted capacity of the inter-lough channel section. This means that Rivers Agency must anticipate significant inflows by drawing down the loughs to ensure flood storage is available. In November 2009 the Erne system experienced a very significant flood event. The water levels were the highest recorded since the changes to the system in the 1950s.
Read more about this topic: Lough Erne