19.6.1.1.2Onshore Cable Route and Converter Station 79. No statutory or non-statutory designated sites are crossed by the cable route, however, the Red Crag present within the eastern half of the onshore cable route (landfall to Tuddenham St Martin) is a reasonably localised stratum and several outcrops in the region are subject to CGS status. The Red Crag in the eastern half of the onshore cable route is therefore considered to have a local value, albeit undesignated, and its sensitivity is considered to be low. The sensitivity of the remainder of the onshore cable route and the converter station is considered to be negligible.
Scenario 1: Pre-installed ducts 80. No trenching is required for cable installation but localised excavation around jointing pit locations, upgrade and construction of access tracks, temporary construction compounds, and laydown areas would still be needed. Excavation within these areas will be limited in depth and extent and would equate to a negligible magnitude therefore the significance will be negligible for both the Red Crag and the remaining geological strata. No further mitigation is considered necessary.
Scenario 2: Trenching and installing ducts 81. Where excavation and trenching would take place, the area of excavation is limited in width and depth (up to 4 trenches, 0.8m wide and 1.5m deep) within the footprint of the works and although removal of some superficial or bedrock deposits would take place there would be no large scale loss of non-designated geology. The limited excavation is considered to equate to a negligible magnitude. Taking into account the embedded mitigation the significance of the impact for the entire onshore cable route and the converter station is considered to be negligible for both the Red Crag and the remaining strata. No further mitigation is considered necessary.
19.6.1.2 Impact 2: Impact on Soils 82.
The potential for direct contamination of soils exists as a result of spillages of fuel, oils or chemicals during construction works. The direct impact would be to contaminate the soil thereby reducing the soil quality and rendering soil unsuitable for re-use within excavations. Soils considered unsuitable for use would then require off-site disposal at a suitable licenced facility. Impacts to soil quality as an agricultural resource are considered within Chapter 22 Land Use. No soils of significant environmental value were identified within the landfall and onshore cable route, however, given the fact that the soils are likely to be permeable in places and susceptible to contamination, the sensitivity of soils along the cable route is considered to range from medium to low. Given that the activities on site
Preliminary Environmental Information May 2014
East Anglia THREE Offshore Windfarm
Chapter 19 Soils, Geology and Ground Condition Page 37
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