An ESB subsidiary and a building contractor have both been convicted in relation to the major landslide at Derrybrien, Co Galway, last year.
At Gort District Court yesterday, Judge David Anderson convicted ESBI Engineering Services Ltd and Ascon Ltd of Kill, Co Kildare, for allowing polluting materials to enter the water at Derrybrien, contrary to the Local Government Water Pollution Act.
Judge Anderson said he had heard three independent engineers and two county council engineers agree that the landslide at the wind farm was caused by construction activities there.
He said he had heard nothing to dissuade him from the view that the prosecution had proved its case and that polluting matter had entered the water as a result of the construction activities being carried out on the site by Ascon with the approval of ESBI.
The judge will make his ruling on penalties and an application for costs made on behalf of Galway County Council tomorrow.
The same summons was dismissed against Gort Windfarms Ltd of Tralee on Tuesday due to lack of liability.
However, Shannon Regional Fisheries Board are also prosecuting Gort Windfarms, ESBI and Ascon and this case will be heard in Gort tomorrow.
Earlier yesterday, the court heard that a land-slip at the wind farm development two weeks before the major landslide should have been an early warning.
However, work was permitted to continue on the site, despite the fact that a smaller land-slip had occurred on October 2nd.
Engineering geologist Mr Turlough Johnson told the court that his company AGEC was engaged by ESBI to investigate the site of the landslide on October 17th.
He stated it was his company's conclusion that it could not say with certainty that the trigger for the slide was at the T68 turbine but the circumstantial evidence led it to conclude that construction activities there, combined with drainage works further down the site, were the likely trigger.
Mr Johnson said their investigation revealed that in early October a slip had occurred at turbine T17, which led to 2,000 tonnes of material moving down the slope before stopping.
The total volume that moved as a result of the major landslide was estimated to be 450,000 tonnes.
Mr Enda Hughes, who had been working as an excavator driver at Derrybrien on the day of the landslide on October 16th, told the court that in the space of seconds, all the trees and vegetation behind him had disappeared and gone shooting down the hill.