2013:403 - Barna, Kerry

A proposed extension to Scartaglin Wind Farm in North Kerry led to a request for an archaeological and cultural heritage impact assessment. The wind farm is located in the townland of Barna on the south-west facing slopes of a hill within the greater Sliabh Luachra area extending from Newmarket in Co. Cork, westwards to Castleisland in Co. Kerry. The landscape is defined geographically by gentle mountain ranges and in the distance to the south the Paps Mountains provide panoramic views over the low lying valleys.  Permission had previously been granted for twelve turbines and the extension was for an additional six turbines. Three turbines (T14-16) were proposed to the south of the permitted wind farm, two (T17-18) to the east and a sixth turbine (T13) to the immediate west. Almost half of the lands proposed for the wind farm consisted of degraded peat now under coniferous plantation. The proposed turbine locations to the south and west of the permitted wind farm are located in reclaimed farmland and overgrown cut-away bog.  A total of 10 test trenches were excavated over a two-day period within reclaimed farmland and areas of coniferous plantation. Access to the turbine locations within the forested areas proved difficult due to the presence of drainage channels and dense vegetation and tree cover. It was decided that the excavation of test trenches in the area of the existing borrow pit to the north of the permitted wind farm was not deemed necessary given the extremely disturbed nature of the ground and the presence of mature woodland. Where possible, the test trenches measured between 60-70m in length to incorporate the turbine bases and the long axes of the hard stands.

The soil profile at Turbine 13 was extremely mixed and consisted of a slight cover of topsoil (0.1-0.15m) overlying a thin deposit of peat which overlay a mixed grey/brown clay and weathered shale. The nature of the deposits indicates that the bog here was reclaimed to marginal grassland. No features or finds of archaeological significance were identified.

Turbine 14 is located in dense forestry to the north-west of proposed turbine (T15) and west of permitted turbine (T5). The trees were initially cleared and a single test trench measuring 75m in length and incorporating the hard stand and the turbine base was then excavated. The overlying peat was quite shallow at the north-east end of the hard stand (c. 0.35m) but increased in depth westwards to almost 0.9m and maintained this depth across the remaining length of the trench. The peat at the turbine base was c. 0.8m in depth and the soil profile was the same as that for the hard stand. The peat overlay a very thin layer of sticky grey clay (0.05-0.1m in depth) and this in turn overlay bright orange till. No features of archaeological merit were noted in the trench.

Turbine 15 is located at the end of a farm trackway in a dense tract of bog heavily overgrown with rushes. The site commands expansive views to the south and south-east across Barna bog which was used for commercial peat extraction by Bord na Mona until 1984.  A single test trench was excavated measuring 75m in length and incorporating both the long axis of the hard stand and the diameter of the turbine base. The exposed soil profile revealed a thin cover of sod and peat (0.15-0.25m deep) overlying mottled orange brown sandy clay with large stone. Nothing of archaeological significance was noted on the exposed surface.

Turbine 16 is located in the south-east corner of a low-lying marginal field of rushes. A single test trench incorporating the hard stand and the turbine base was excavated to the surface of the subsoil. The trench measured 70m in length and excavation revealed a thin cover of topsoil consisting of black peat rarely exceeding 0.2m in depth and in places just 0.1m deep. No features or finds of archaeological merit were present in the excavated area.

Turbine 17 is located in dense forestry to the east of the permitted wind farm. The forestry was initially cleared and a single trench measuring 70m in length was excavated. The soil profile consisted of an upper brown layer of sod/peat (0.2m) which overlay a layer of black peat measuring c. 0.2m in depth which in turn overlay the natural blue/grey clay with iron oxide staining.  Nothing of archaeological significance was exposed on the surface of the subsoil.

Turbine 18 is located on the side of a trackway in dense forestry east of the permitted wind farm. The forestry was initially cleared and a single trench measuring 70m in length was excavated. The soil profile indicated that peat had been extracted from this area in the recent past.  The upper 0.2m of overburden represented recent peat growth and this overlay a layer of darker peat (c. 0.2m deep) which had been left in situ during manual peat extraction. The peat overlay grey clay mottled with sandstone. No features of archaeological significance were uncovered.

A small area proposed for gravel extraction to the south of the forest track connecting Turbines 17 and 18 was tested. A single test trench measuring 25m in length was excavated.  The peat at the north-west end of the trench was quite shallow (c. 0.22m) but it increased in depth to 0.8m towards the north-east limit of the trench. It overlay light orange/brown clay with large sandstone boulders and no features or finds of archaeological significance were present.

Another borrow pit was proposed to the immediate south of proposed Turbine 18 along a fire belt extending north-west/south-east from the existing forestry road. The trench measured just 15m in length as it became apparent that all of the topsoil and peat had been removed from this area during the construction of the fire belt.

Access to the turbine locations will be gained predominantly via the existing forest road network and overgrown stretches of fire belts through the commercial forestry. Two test trenches were placed in those areas of the proposed extension to the wind farm where the access roads will involve the removal of undisturbed topsoil and peat. A trench measuring 45m in length was excavated through a pasture field to the north-east of the proposed location of T15. This road will connect with the existing forestry track providing access to permitted T5. The trench extended from the south-east corner of the field adjacent to a land drain and extended to the edge of the forestry. Excavation revealed a very thin cover of topsoil consisting of black peat (0.1-0.15m in depth) overlying mottled orange grey clay. Nothing of archaeological significance was uncovered. A single test trench was placed along the proposed access road that will connect the permitted T11 to T17 and T18. The road mostly goes along an existing poorly maintained trackway that flanks the northern limit of the forestry. The western end of the access road will travel through undisturbed ground before it enters the forestry and a 50m long test trench was placed along this section of the route. The peat reached an average depth of 0.7m and in places was almost 1m in depth. It overlay natural grey stony clay and no features or finds of archaeological merit were present.

Rostellan, Midleton, Co. Cork.