Months after Storm Éowyn left a trail of destruction across Northern Ireland, NI Water has said it will cost approximately £650,000 to repair the damage it caused to the Mourne Wall.
A recently completed survey to assess the damage found there were 63 individual collapses along the wall across six mountains in the Mournes.
Storm Éowyn brought winds of more than 90mph when it hit on 24 January and left thousands without power.
The red warning storm also caused a nine-week closure of Silent Valley Reservoir in the Mournes due to the damage, with access to many walking trails still restricted by NI Water.
The full extent of the damage to the 22-mile Mourne Wall by Storm Éowyn was found after a survey, which began on 24 February, was completed on foot.
NI Water, which owns the wall, said the survey was "time consuming" due to the nature of the task to inspect each section of the iconic wall.
It was found that 700m of the Mourne Wall was damaged with 63 individual collapses across six mountains, including Slieve Donard – Northern Ireland's tallest mountain.
In 2023, NI Water announced a £2.5m investment for phase two of the Mourne Wall Restoration Project.
Phase one was completed in 2018 and saw more than 600 repairs undertaken.
Phase two involved repairs to on Slieve Muck and Rocky Mountain.
Most damage to areas that were not restored
However, NI Water confirmed that only one section repaired through the restoration project collapsed due to Storm Éowyn.
"The estimated cost for repairs will be approximately £650k," NI Water told BBC News NI.
"NI Water is now preparing a business case and repairs may be included in the 2025/2026 Capital Delivery Programme subject to funding approval.
"Fortunately, the majority of the damage was to areas that have not been updated under the Mournes Restoration Project scheme.
"There was one section of repaired wall that was damaged by the collapse of the original wall alongside it."
The Mournes is an Area of Outstanding Natural Beauty and also suffered from more than 140 wildfires last month.
Minister of Agriculture, Environment and Rural Affairs Andrew Muir described the wildfires as "rural arson".
What is the Mourne Wall?
The Mourne Wall is 22-miles long and was built from 1904 to 1922.
Known as 'the handrail of the Mournes' as it helps guide hikers, it is made of natural granite stone using only traditional dry stone walling techniques.
Its construction was overseen by the Belfast City and District Water Commissioners and was designed to keep livestock from contaminating water supplies.
The Mourne Wall is synonymous with the Mourne Mountains and is Northern Ireland's longest listed building.
In March 2024, NI Water completed the second phase of essential repairs on the 100 year old wall through the Mourne Wall Restoration Project.
More than 300 repairs were completed across 15 mountains during phase two of the project, bringing the total number of collapses fixed on the structure to over 900 since the project began in 2017.
