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in the river valley. The initial landslide continued until October 19th where it stopped at an elevation of 195mupslope of the locally named “Black Road”. On October 29th following heavy rain the slide was reactivated andcontinued down slope for another 1.5km blocking two roads, including the “Black Road”.The area where the failure began, or “head” of the slide, is adjacent to the construction site for one of theturbines – No. T68. The area slopes very gently to the south at less than 10°. In this area the peat has beenexcavated over an area of approximately 30m sq. The depth of the excavation was not apparent as it was waterfilled, but it certainly exceeds 2m in depth. Also the nature of the subsoil or bedrock in the area could not beascertained. Adjacent to the southern side of this excavation is an access road, which is one of several parallelroads that run approximately east/west. These roads are constructed as “floating roads” on the peat, consistingof a layer of felled logs, covered with a membrane and hardcore. At the failure the road had been displaceddownslope by up to approximately 3m and had subsided by approximately 1m. Downslope of the road the bogsurface had failed and all the trees had collapsed and been moved downslope from an area initially ca.30mwide.Below the upper area where the bog initially failed the displaced mass became a bog flow, where the liquefiedpeat flowed, and was confined for the most part within the steep-sided stream channel lower down. The areadamaged by the peat is confined almost entirely to the forestry and within the stream banks, only over-toppingthe bank at the dammed bridge areas (Plate 3.2). No occupied houses were directly affected by the flow,although an abandoned farmhouse was in the path of the flow. Two bridges were closed for several days.Plate 3.2 Derrybrien LandslideThe material displaced consisted almost entirely of peat and the vegetative cover. There was little bedrock orsubsoil material moved in the failure. Weather at the time of the initial failure was quite dry, although the secondphase of the movement of the bog appears to have been triggered by heavy rainfall. Specialist consultants wereemployed by the developers to investigate the peat slide. The conclusion reached was that there were twocontributory physical factors, a zone of weak peat and proximity of a natural drainage channel. It was alsoconcluded that activity associated with the construction of the wind farm was also a contributory factor. Theirreport also made recommendations for improvements in construction methods.3.9 Irish Landslides Database - Recommendations• The Irish Landslides Database should continue to be expanded on an ongoing basis• Liaison should be established with other agencies in both the public and private sectors to progress theacquisition of data on past events21