EHG1556 - Walkover survey - Isle of Eigg Electrification project

A desk based assessment and walkover survey were undertaken by Archaeological and Ancient Landscape Survey (AALS) in 2007 in advance of a proposed electrification scheme on the Isle of Eigg. The residents had previously relied upon individually owned, and installed, generators and hydro plants for their electricity supply. The proposed electrification scheme, a combination of hydro power, a wind farm and a bank of solar panels would enable the supply of at least 5kw of power to every household, and at least 10kw of power to business premises on the island. The walkover survey covered the installation sites (Wind, Hydro and Solar) and the routes of the necessary cable network supplying the individual households and business premises. Initial discussions revealed that prior to the siting of infrastructure and the routing of supply cables, a great deal of thought had been given to the archaeology of the island. The recorded archaeological baseline had been established and the siting of the wind farm, hydro plant and cable routes had been chosen with this in mind. The survey would therefore be concerned with unrecorded archaeological sites, and, where necessary, the adjustment of the chosen infrastructure sites and cable routes to allow buffer zones around the known archaeology The majority of the cable-work would be laid in the roadside verges of the many roads and tracks which served the individual consumers. All cables would be buried to a depth of 800mm. As these roadside verges have been drained and extended over many years it was not anticipated that archaeological remains would be encountered. These areas required only a rapid walkover to assess the potential for archaeology. Two of the three installations (windfarm and hydro scheme) and one cable route however lay on hill or farmed ground. These 3 areas were walked over and visible archaeological sites recorded, in order that infrastructure, cable work and access routes did not destroy currently unrecorded archaeological sites. A 50m wide corridor was walked along all cable and pipe-work routes not in roadside Verges or access tracks. The survey demonstrated that, as long as agreed sites and routes were adhered to, there would be little need for follow-up watching briefs during installation of infrastructure and supply cables. The only instance where professional archaeological input might be recommended was during the cutting of the cable trench across the bog below Sron Laimhrige east of the farm at Laig. This route woud pass some 80m south of the find-spot of a possible Viking stem and stern posts found during draining in the 1850's. However, even this might be considered unnecessary as the cable would be buried no deeper than 0.8m below the surface, considerably shallower than the depth of the drainage ditches in the area - all of which were from 1.5 to 2.0 meters deep. <1>