Lough Erne water level maintenance
Water level control in Lough Erne is undertaken in conjunction with the Electricity Supply Board 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 154ft. (Apr. – Sept.) / 155ft. (Oct. – Mar.), and in the Lower Lough between 147ft. and 152ft. These levels relate to the base reference at Poolbeg for imperial (i.e. feet and inches) measurements.
Water levels in Upper and Lower Lough Erne are managed by control structures located at Portora (Enniskillen), Cliff (near Belleek) and Ballyshannon in the Republic of Ireland. The Agency is responsible for the control structure at Portora only. During the summer period the Electricity Supply Board aims to maintain the water level at Portora, at or above, 150ft. to avoid the need for these gates (locks) to be closed. This is to prevent undesirable restriction to boat traffic using the navigation facilities at this 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. Allowance for this has to be made, as best as possible, in level control management procedures.