Limekiln Wind Farm Section 36C Variation EIA Report 13. Geology, Hydrology and Hydrogeology .......................................................... 1 13.1 Summary .................................................................................................... 1 13.2 Introduction ............................................................................................... 1 13.3 Legislation, Policy Context and Technical Guidance ................................... 4 13.4 Stakeholder Consultation ......................................................................... 14 13.5 Assessment Methodology and Significance Criteria .................................. 16 13.6 Baseline Conditions .................................................................................. 22 13.7 Identification and Evaluation of Effects .................................................... 35 13.8 Environmental Measures Embedded into the Development Proposals ...... 42 13.9 Assessment of Hydrology and Hydrogeology Effects ................................ 55 13.10 Cumulative Effects and Interaction of Effects ....................................... 68 13.11 Consideration of Optional Additional Mitigation or Compensation ......... 69 13.12 Conclusions of Significance Evaluation .................................................. 69 13.13 Comparison of Significance Outcomes between Revised Consented and Consented Development .................................................................................... 70 13.14 Implementation of Environmental Measures ......................................... 71 13.15 References ............................................................................................ 73 Figures 13.1 Revised Consented Development Overview 13.2 Superficial Geology 13.3 Bedrock Geology 13.4 Hydrological and Hydrogeological Receptors 13.5 Drainage and Elevation Map 13.6 Hydrological and Hydrogeological Constraints Geology, Hydrology and Hydrogeology June 2021 Volume 1: Written Statement 13-0 Limekiln Wind Farm Section 36C Variation EIA Report 13. Geology, Hydrology and Hydrogeology 13.1 Summary 13.1.1 This chapter considers the potential effects of the proposed Limekiln Wind Farm Section 36C Variation Application (hereafter referred to as the ‘Revised Consented Development’) on geology, hydrology and hydrogeology. 13.1.2 The scope of the assessment was determined through a combination of a desk study to identify the baseline water environment setting relating to the site and surrounding area and consultation with relevant stakeholders. 13.1.3 The assessment has highlighted several potential effects on site hydrology and hydrogeology, primarily during wind farm construction, but potentially also during site operation. These effects are associated with a range of activities, most notably access track construction. The most serious potential effects are associated with sediment-laden runoff from exposed ground entering watercourses. 13.1.4 Mitigation measures incorporated into the scheme’s design would reduce the likelihood and magnitude of a pollution event or other impact resulting from the Revised Consented Development’. These mitigation measures have been defined for each element of the on-site development. The measures would be undertaken in accordance with current best practice and would ensure that there are no significant effects on hydrological or hydrogeological receptors as a result of the Rpevised Consented Development. 13.1.5 Also, no significant operational, decommissioning or cumulative effects are predicted as a result of the Revised Consented Development. 13.2 Introduction 13.2.1 This chapter considers the potential effects of the Revised Consented Development on geology, hydrology and hydrogeology during its construction, operation and decommissioning phases. Background 13.2.2 An assessment of the potential hydrological and hydrogeological effects of the proposed Limekiln Wind Farm was undertaken for the Environmental Statement (ES) submitted in 2012. The assessment was based on the collection of a wide range of data and information from published material, plus consultations with statutory bodies, principally the Scottish Environment Protection Agency (SEPA) and The Highland Council (THC), and other stakeholders relating to the local and wider hydrological environment. In addition, a site visit by a Wood hydrologist was undertaken on 03 November 2011, which permitted an inspection of water features and an assessment of the existing land use within the site. 13.2.3 The original proposal was the subject of a Public Local Inquiry (PLI). The overall conclusions in the Report to Scottish Ministers in 2015 stated that ‘Other than the potential impact on wild land, we conclude that the proposal would not give rise to any detrimental impacts, either singly or cumulatively, sufficient to outweigh the benefits of the proposal.’ 13.2.4 In 2016 the Applicant submitted a Section 36 Application with the same proposed infrastructure and layout as the first Section 36 Application submitted Geology, Hydrology and Hydrogeology June 2021 Volume 1: Written Statement Chapter 13 – Page 1 Limekiln Wind Farm Section 36C Variation EIA Report in 2012. The Application, ES and other documents that were submitted in support took account of relevant changes in policy or guidance that had occurred in the intervening period since the first Application and was supported by additional information regarding wild land and updated information on cumulative impacts. 13.2.5 In February 2017 the planning committee of THC voted to object to the Section 36 Application on the grounds of a loss of recreational amenity close to the village of Reay and an unacceptable impact on Wild Land Area 39 - East Halladale Flows. The Scottish Ministers therefore referred the Section 36 Application to the Directorate for Planning and Environmental Appeals (DPEA) to be examined at PLI. 13.2.6 In response to this, the Applicant removed three turbines (T19, T20 and T21) and the associated access tracks from the proposed wind farm. Supplementary Information (SI) to support this layout was submitted in September 2017 and it was consented by the Scottish Ministers in June 2019 (hereafter it is referred to as the ‘Consented Development’). The Applicant has subsequently satisfied the planning conditions required for construction to commence and has commenced construction. 13.2.7 Table 13.1 presents a summary of the conclusions from the previous applications highlighted above, and from the Revised Consented Scheme. Table 13.1 Summary of conclusions for geology, hydrology and hydrogeology from previous applications 2012 ES (24 Turbine 2016 ES (24 2017 SI (21 2021 Section 36C Layout) Turbine Layout) turbine layout - Application (21 Consented Turbine Layout Development) with amended access tracks – Revised Consented Development) The assessment As outlined above, the No supplementary This EIA Report takes highlighted several Applicant submitted information was account of relevant potential effects, this Application with required to be changes in policy or primarily during wind the same proposed submitted for guidance since the farm construction infrastructure and geology, hydrology previous Application (though potentially also layout as the that and hydrogeology. and up-to-date data during site operation submitted in 2012. sources. and decommissioning). These effects were This ES took account With the removal of associated with a range of relevant changes in proposed works of activities, most policy or guidance that within the Sandside notably access track had occurred in the Burn catchment and construction and the intervening period with a Water Quality resulting potential of since the first Monitoring Plan sediment-laden runoff Application and was already being from exposed ground supported by implemented, this entering watercourses. additional information EIA concludes that regarding wild land the potential effects Specific mitigation and updated upon the water measures were environment were Geology, Hydrology and Hydrogeology June 2021 Volume 1: Written Statement Chapter 13 – Page 2 Limekiln Wind Farm Section 36C Variation EIA Report 2012 ES (24 Turbine 2016 ES (24 2017 SI (21 2021 Section 36C Layout) Turbine Layout) turbine layout - Application (21 Consented Turbine Layout Development) with amended access tracks – Revised Consented Development) identified to reduce the information on the same as likelihood and cumulative impacts. previously i.e. not magnitude of a pollution significant for all event or other impact This Application potential receptors resulting from the included a and for all proposed development on the requirement for PWS activities. water environment, and surface water namely implementation quality monitoring of a Drainage (secured by condition Management Plan; to the grant of any implementation of a consent). As with the Pollution Prevention previous Application, Plan; and adequate the potential effects pollution control upon the water measures throughout environment were the site. All mitigation assessed as not would be included significant for all within the Construction potential receptors Method Statements and for all proposed (CMS) for the site, and activities. specific CMS would be produced for the most sensitive construction operations. All activities would adhere to best practice guidance and follow appropriate requirements and conditions associated with Controlled Activities Regulations (CAR) licensing. With the application of the specific