BUILDING BRIDGES? The current bridge over the Glenisland River on the R312 Castlebar to Belmullet road. Mayo County Council’s application for a new bridge was turned down by An Bord Pleanála on environmental grounds.
Road improvement works on the controversial R312 Castlebar to Belmullet road have been set back by one year.
Local county councillors were informed of this news at the December meeting of the Castlebar Municipal District of Mayo County Council.
It comes in the wake of a decision by An Bord Pleanála to turn down Mayo County Council’s planning application for a new bridge over the Glenisland River as part of the improvement works.
Mayo County Council Engineer Ann Sweeney told the meeting the refusal has ‘probably’ set the project back one year.
The decision of An Bord Pleanála to refuse the council’s initial application was criticised at the October meeting of Mayo County Council.
“Everyone is preserved but the human,” said Cllr Gerry Coyle, who described the existing R312 as ‘a dirt trail’.
An Bord Pleanála cited the impact the council’s proposed development for a precast box culvert bridge might have on the Freshwater Pearl Mussel and Atlantic Salmon indigenous to the Glenisland River and said a clear span bridge was preferable.
Mayo County Council Chief Executive Peter Hynes told Cllr Coyle ‘we share your disappointment’ and that the council submitted their application ‘in confidence’ of approval.
However, an expert in the construction of roads and bridges in Special Areas of Conservation (SACs) has criticised the council’s initial proposal for a box-culvert bridge.
George O’Malley, an expert in forestry operations and who has worked for over 30 years on the construction of bridges and roads through SACs in forests in Ireland, expressed his surprise that the council applied for a box culvert bridge in an SAC.
Mr O’Malley, who ran in the 2016 General Election in Mayo, said a ‘clear span bridge was the only option for the council here’.
“I am one of the biggest critics of designated lands but this is not even up for debate. I cannot understand why the council were trying to put in a box culvert in an SAC that is a salmon spawning river and at risk from flash flooding as it is a mountain stream. A box culvert bridge construction would involve the excavation of the river bed to a depth of half a metre. It’s very likely that box culverts that have been installed in such locations will have to be removed. A further even more critical point here is the role of the OPW which was deemed the appointed authority for consenting infrastructure works over rivers by the EC Regulation (Assessment and Management of Flood Risks) S.I 122 of 2010. I didn’t see any reference in the ABP report to a Section 50 application having been submitted to the OPW.
“A clearspan bridge can exceed 40 metres wide without touching the river bed. This river crossing is much narrower than that.
“Designation of land is a fact of life in the west of Ireland and we have to be aware of it. I would be critical of ABP at times but completely support them on this,” he said.
Conflict over method
In applying for a box culvert bridge, the council went against the recommendation of their ecologist, who recommended a clear span bridge in the Natura Impact Statement (NIS).
A Natura Impact Statement is a document the council must submit when carrying out works on Special Areas of Conservation (SACs) and Special Protection Areas (SPAs).
This NIS stated a clear span was preferable as ‘the Glenisland River should be left insitu and not disturbed during the construction phase’. This was a view shared by Inland Fisheries Ireland and the Department of Archeology, Heritage, the Gaeltacht, Regional and Rural Affairs (responsible for the National Parks and Wildlife Service).
Despite this, the council proposed that a box culvert bridge measuring 21 metres long, six metres wide and three metres high be installed. They also said that a ‘temporary diversion’ of the Glenisland River would be needed during installation of the bridge.
An Bord Pleanála requested that Mayo County Council submit further information pertaining to their selection of a pre-cast box culvert.
The council made a number of points. Firstly, they state that they have ‘worked closely with Inland Fisheries Ireland to develop a pre-cast box culvert that is designed to be 300mm deeper than the river bed, thereby providing the opportunity for natural indigenous material to be introduced to mimic the surrounding river bed’.
They also state that while their Natura Impact Statement ‘expresses a preference for a clear span bridge’, there is a risk of ‘spillages and contaminants’ entering the water by the construction of the clear span bridge into the river banks.
They say that a box culvert can be installed in a single day and go onto say that while the NIS said the river diversion proposed by the council during the installation of the box culvert is not ecologically preferable, the council ‘have developed a method of undertaking such diversion that virtually eliminates the risk of any silt entering water courses’.
George O’Malley believes the council’s arguments contradict each other.
“From my experience of constructing clearspan bridges, if done right not as much as a cup of concrete would go into the water. It is not credible to make a statement that a clearspan bridge will risk ‘spillages and contaminants’ entering the water and, at the same time, expect us to believe that diverting the river will not result in sediment getting into the river.
“By the time the river is diverted, there will have been a lot of disturbance of the SAC through excavation to remove tree stumps and shrubbery at the entry and exit of that loop, segretation of topsoil (and its protection from runoff) from subsoil and rock. The council say it has developed a method of undertaking a river diversion that virtually eliminates the risk of any silt entering the water. I think that’s pie in the sky, particularly in that location given the presence of light sandy and alluvial soils. It’s like trying to make an omelette without breaking any eggs,” he said.
“The golden rule when carrying out forestry operations close to waterways is get out of the water and stay out of it. A clear span bridge is the only solution here yet the council insisted, despite the best professional advice recommending a clear span bridge, to look to use a precast box culvert.
“The council would not now be facing a one year delay if they applied for a clear span bridge. The decision to proceed as it did is baffling” he added.
A spokesperson for Mayo County Council said the council are currently ‘trying to work out the best way to proceed’.
He said ‘it wouldn’t be unusual’ for a council to go against their own Natura Impact Statement and said he believed the Office of Public Works did not have ‘a role in this particular project’.
“We felt what we put forward was good. An Bord Pleanála didn’t agree. More often than not they do agree with us but there’s no point having them there if they have to agree with us all the time.”