The new gates are expected to last another 50 years
Sluice gates that have controlled the waters of Lough Erne for more than half a century have been replaced.
The huge flood protection barriers in Enniskillen managed the flow between the upper and lower sections of the waterway.
Four new 13 tonne gates have now taken their place at the Portora Castle site.
Stephen Dawson from the Northern Ireland Rivers Agency said the old gates "had reached the end of their useful life".
"We are delighted the refurbishment has gone according to plan. We expect the new gates to last at least for another 50 years," he said.
The complex replacement project took four months to complete.
The work was funded by the Republic of Ireland's Electricity Supply Board (ESB), which generates hydro-electric power from Lough Erne at their station at Cathaleen Falls near Ballyshannon in County Donegal.