Most of the top of the weir is bone-dry and dirt-brown, covered in dead moss and small white feathers. This is where Fermoy’s well-fed ducks sunbathe.

Below, water pours through holes of varying size, eroding away the weir’s foundation. The entire edifice is crumbling, and each seasonal flood brings fresh damage as fallen trees weaken it further.

Fermoy weir is a listed, protected structure, the property of Cork County Council. Councillors claim they’re committed to repairing the weir, and preliminary investigations are said to be underway, with repairs reported to be budgeted at €1.57m.

However, with those repairs rumoured to take a staggering 40 months from the eventual start date, local activists say there is no sense of urgency on the council’s part.

Stepping carefully from the Triangle Field on the Blackwater’s north-western bank, you’ll have to pick your way immediately over a badly-broken section. A decade ago, Inland Fisheries Ireland decided the best way to assist migrating salmon over Fermoy Weir was to change forever a piece of infrastructure two centuries old.

That didn’t work, and local anglers ended up ferrying migrating salmon over the weir.

Making your way along the weir, from its highest point, now two feet above the water upstream, step over the elver pass — a small concrete ramp built to attract eels upstream — out to the salmon pass, halfway across the river.

The salmon pass is a masterpiece of regency-era engineering, a stepped series of rectangular limestone pools designed to create at its base turmoil in the water to attract salmon and to draw them up the steps and further along their journey from Youghal to Banteer and home to spawn.

Last summer, the surface of the weir was dry but water ran freely down the salmon pass. Now, with the weir breached badly downstream and water finding its own level, there’s barely a trickle. A cloud of dust rises when you step on the moss-covered stone tiers of the salmon pass.

From the salmon pass, the weir sweeps gently to the left and east to the bridge, directing the upper part of the river through the first two southern eyes of the bridge, toward the former sluice gates by O’Neill Crowley Quay, where, across from the Garda station. it spills over in a powerful cascade.

At the bottom of the salmon pass, you can step-stone under Thomas Kent Bridge, recently named for the 1916 patriot. Reflected sunlight sparkles overhead, and the underside of the bridge is pock-marked with holes drilled during the Civil War, when General Liam Lynch planned to dynamite the bridge.

East and south toward the former sluice gates, you can see the worst damage to the weir, where two chunks have washed away and a third looks set to follow. Water is gushing out, causing historically low water levels upstream.

There has been a weir on Fermoy’s Blackwater for at least 800 years, since the Cistercian monks built their abbey Sancta Maria de Castro Dei (Our Lady of the Camp of God) somewhere on what is now Ashe Quay.

Before ever a bridge crossed the river, the monks ran a ferry. Thomas Cromwell mentions the weir in 1540, in his inventory for Henry VIII, prior to the dissolution of the monasteries. Centuries after the abbey was lost to history, in 1791, the Scottish businessman John Anderson bought the old abbey lands and founded the modern town.

Granting a free site to the British Army for barracks on the north of the river, Anderson also gave free sites to the Church of Ireland, for Christchurch, and to the Catholic Church, for St Patrick’s.

Anderson built the modern weir to shape the Blackwater, channelling its power down through the sluice gates to Mill Island, the industrial base for his fledgling town.

The mill closed 50 years or more ago, but over two centuries, an entire ecology has grown around John Anderson’s weir, and it forms the picture postcard of the town.

The river west of the weir is an amenity of stunning beauty, and Barnane Walk is where Fermoy goes for a stroll. It’s the route of An Spiorad Saor John Mahon, Ireland’s only MKIII wheelchair-accessible boat.

It’s also home to at least 12 sports clubs, including anglers, kayakers, triathletes, Atlantic swimmers and to oarspeople like the Olympians the Rice brothers and Gearoid Towey.

“The Saga of Fermoy Weir”, as some in Fermoy call it, began in 2006 when Fermoy Town Council, then the owner of the weir, was informed by officials from Inland Fisheries Ireland and from the then Department of Communications, Marine and Natural Resources that the EU had received a complaint that salmon were becoming trapped at Fermoy Weir, and that the EU was demanding the weir be removed, and be replaced with a rock ramp pass, a tiered, crenellated stone structure similar to that installed in Kilkenny.

The then minister for state for Fisheries, John Browne, came to Fermoy in 2007, and upstairs in Fermoy Rowing Club said Ireland would be fined “hundreds of thousands of euro a day” by ‘The Man from Europe’ if the problem wasn’t solved.

Plans for a rock ramp pass were produced, and Rowing Club members noted the proposed structure was 16 inches lower in height than Fermoy Weir. The point was made that 16 inches at the weir would translate as a metre in lower water levels upstream by the Rowing Club.

Inland Fisheries Ireland officials dismissed such concerns, and spoke of their agenda to remove every single redundant weir (no longer powering a mill) in the country, saying they have the power to recommend such removals under Section 116 of the Fisheries Act.

In 2009, members of Fermoy Rowing Club and members of Fermoy angling clubs travelled to Brussels, thanks to then MEP Kathy Sinnott, and met with officials.

Following the meeting, the EU said it would back a repair of the weir.

Following a later meeting in Government Buildings, the then minister of state, Conor Lenihan wrote to Fermoy Town Council ordering them to carry out repairs. Nine months later, Fermoy Town Council wrote back to ask the minister for funding.

In a Catch 22 response, Lenihan replied that he couldn’t commit state funding for a repair, as his advisors said, a repaired weir would not be the optimal solution.

It is now almost 60 years since the last serious repair of Anderson’s weir, when the Burke brothers, local craftsmen, held back the river using nothing but sandbags, and their own ingenuity.

Much of the salmon pass is badly damaged now, with a long section of cap-stones washed away. A few years ago, a temporary patch-job was carried out. That has now fallen apart.

During Fermoy’s recent flood relief scheme, the Office of Public Works widened O’Neill Crowley Quay, pile-driving into the river bed.

Widening the quay narrowed the river beside it, and — for reasons unknown — the historic sluice gates were removed and the mill race all-but closed off. That has had the effect of funnelling a continual, concentrated torrent of water over the weir at O’Neill Crowley Quay, across from the Garda Station. That force of water has broken the weir wall, and that damage looks likely to worsen.

That cascade also creates a huge turbulence in the water downstream and causes a build-up of gravel islands in the river, which clog the path of migrating salmon. That turbulence confuses the salmon, causing them to become trapped at the south-eastern base of the weir, where they attempt vainly to leap a six-foot wall.

Thousands of salmon are likely to be injured or killed in Fermoy in the coming months, and locals warn that the weir is now so badly damaged the next flood could finish it.

The fate of Fermoy Weir is a local story, but it’s one with national resonance. If Inland Fisheries Ireland is sincere in its intent to remove every redundant weir in the country, then any such weir, including Dublin’s Island Bridge weir, and Galway’s Salmon Weir, might be next.

- Donal O’Keeffe is a former secretary of Fermoy Rowing Club.