have been avoided through the design of the proposed development. Other areas in the west of

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1 Limited Technical Appendix 2.6: Peat Management Plan Introduction This report presents an outline Peat Management Plan (PMP) based on the results of a peat probing survey undertaken for the proposed (the proposed development) near Langholm, Dumfries and Galloway, Scotland A programme of site reconnaissance was undertaken in February 216 and in October 216. The methodology followed and detailed results are set out in Technical Appendix 2.7: Peat Slide Risk Assessment This PMP has been prepared in accordance with the requirements of the Guidance on the Assessment of Peat Volumes, Reuse of Excavated Peat and the Minimisation of Waste 1. This is a Stage 1 PMP and the objective is to demonstrate that: the extent and characteristics of peat at the study site have been investigated; excavations in peat have been minimised wherever possible through design iterations and adoption of appropriate design hierarchy 2 ;and that excavation and subsequent management of peat, including an estimation of quantities, has been considered as part of the EIA A detailed Stage 2 peat management plan would be developed as part of the detailed design phase of the project as part of the Construction and Decommissioning Environmental Management Plan (CDEMP). It is expected that the peat management plan would follow the general principles set out in this PMP Background The proposed development is described in Chapter 2: Proposed Development of the Environmental Statement (ES). site within a BGS mapped area of peat 3. The maximum depth recorded was 3.8 m. Generally, peat was shallow across the remainder of the site and modified within the forestry plantation areas Nationally important resource carbon-rich soils, deep peat and priority peatland habitat and areas likely to be of high conservation value are present in the west and south east of the site, although have been avoided through the design of the proposed development. Other areas in the west of the site are identified as carbon rich soils with some areas of deep peat and areas where no peatland habitat is recorded. Mineral soils are identified in the valley within the centre and east of the site Figure in Technical Appendix 2.7: Peat Landslide Hazard and Risk Assessment illustrates the extent of peat Peat Management Plan Peat Characteristics As discussed in Chapter 3: Design Evolution and Alternatives, the design of the site has aimed to minimise the amount of peat excavation required during construction. As such, the majority of the site infrastructure does not overlie peatland habitats and would not entail the excavation of large quantities of peat The peat probing survey found that peat was generally absent or shallow across the majority of the site, with organic soils not classified as peat (<.5 m) accounting for 66% of probe locations. Most of the peat deposits were identified in the western and southern parts of the site, with probe depths typically found to be between.5 m and 1. m depth. In the western part of the site, occasional isolated, deeper pockets of peat between 1. m and 2.5 m were recorded. A maximum depth of 3.8 m for peat was also recorded in the west of the site. Peat recorded within forestry plantation areas in the west of the site was found to be highly modified and degraded as a result of forestry and impacts associated with its infrastructure. Geology and Soils The superficial deposits across the site are generally absent on the higher elevations and steep slopes. Between the higher areas and steep slopes, the superficial deposits comprise Devensian glacial till (part of Langholm Till Formation), with smaller areas of alluvium, peat and head deposits The solid bedrock geology consists of lower Paleozoic (undifferentiated) mudstones and Wackes of Silurian Age. Bedrock is sedimentary comprising predominantly calcareous sandstone and siltstone, but occasionally interbedded with mudstone. All sedimentary rocks are thought to be deep sea turbidites. Extent of Peat Coverage Peat deposits are mapped in the western and southern parts of the site. Peat probing undertaken by Ramboll Environ confirmed the presence of peat, this largely corresponded to the 1:5, scale BGS geological mapping. Deep peat (in excess of 1 m thickness) was recorded in the west of the The design process avoided placing any turbines on areas of peat in excess of 1 m depth. The only part of the proposed development located in peat deeper than 1 m is the existing track located between turbines 4 and 5; however this section of track is less than 2 m in length. It is proposed that the existing track is widened to accommodate the construction traffic but it is considered that the peat is likely to be highly modified given the existing forestry land use, and the presence of the existing cut track through this area. General Principles Peat and peaty soil would be stripped from the surface of all areas requiring excavation such as the construction compound, excavated track sections, crane hardstandings and turbine foundations. Where peat thicknesses exceed approximately 1 m, tracks would be designed to float on the peat in order to reduce disturbance and excavation volumes, however it is assumed the requirement for floating construction would be minimal as the design sought to avoid deep peat Where appropriate, the peat would be stored temporarily alongside the works for use in reinstatement and landscaping at the end of the construction. In line with best practice, the 1 Scottish Renewables, & SEPA (212) 'Guidance on the Assessment of Peat Volumes, Reuse of Excavated Peat and the Minimisation of Waste Version 1. URL Design hierarchy as detailed within the SR/SEPA guidance: prevent excavation, reduce excavation volumes and reuse excavated peat in a manner to which it is suited. 3 Identified on the BGS 1:5 scale superficial deposits map. TA 2.6: Peat Management Plan Ramboll Environ

2 Limited following order of preference would guide the reuse of peat in reinstatement and landscaping activities: Reinstatement locally around construction works peat and peat soil excavated for the construction compound and turbine foundations would be replaced on completion of the works as part of the reinstatement of the site and to minimise movement of materials. Along access tracks the peaty soil would be used in the permanent landscaping of the tracks in strips on one or both sides of tracks as identified during detailed design. Design criteria shall include consideration of peat thickness and strength, slope angle and effect of surcharge on stability, and will include specification of maximum allowable reinstatement depths. Landscaping in and around site infrastructure, including borrow pits any cut and/or fill sections of infrastructure and worked borrow pit areas would be landscaped using excavated peat where required to reduce visual impact Shallow peat will have accumulated relatively slowly under a vegetation community dominated by vascular plant species. The roots of these species from a fibrous network within the peat which gives it a high degree of internal coherency. Given the shallow depth of peat or peaty soils at the site (with 66% of probe locations recording <.5 m of peat) and the fact that the proposed development was designed to avoid peat over 1 m depth, it can be assumed that the vast majority of peat likely to be excavated would be suitable for reuse on site in reinstatement and landscaping works. On this basis and for the purposes of this Stage 1 peat management plan, all peat excavations are assumed to be suitable for reuse on site. Further detailed analysis of the volumes of acrotelm and catotelm would be provided as part of a detailed Stage 2 PMP prepared following pre-construction ground investigations. Excavation Volumes The total volume of peat excavation has been calculated based on the average peat depths recorded (through the peat probing survey), combined with the permanent land-use areas set out in Technical Appendix 2.1 of the ES. It is assumed that any peat excavated through temporary land use, for example the temporary storage area and temporary turbine laydown area, would be stored in accordance with good practice guidance for reinstatement following construction. Table sets out the potential volumes of peat (predominantly peaty soil) that would be excavated as part of the construction work. Table 2.6.1: Estimated Volumes of Peat (m 3 ) Infrastructure sited on peat Peat Volume (m 3 ) Assumptions Turbine crane hardstanding 3,23 5 crane hardstandings sited on peat. Assumes area of 1,292 sq m per turbine and.5 m depth. Turbine foundation turbine foundations sited on peat. Assumes area of 314 sq m per turbine and.5 m peat depth. Cut access track 5,397 1,285 m of track sited on peat. Assumes 6 m width and.7 m depth. Existing track upgrades 2, m of existing track sited on peat. Assumes widening by 3 m required and.9 m depth. Track turning head areas 2,351 3 turning heads sited on peat. Assumes total area for 3 turning heads as 3,359 sq m and.7 m peat depth. Borrow pit search areas 864 Small section of borrow pit 3 search area sited within peat. Assumes area of 1,8 sq m and.8 m peat depth. 4 Scottish Renewables, & SEPA (212) 'Guidance on the Assessment of Peat Volumes, Reuse of Excavated Peat and the Minimisation of Waste Version 1. URL - Ramboll Environ Table 2.6.1: Estimated Volumes of Peat (m 3 ) Infrastructure sited on peat Peat Volume (m 3 ) Assumptions Total 14,779 Peat Reuse Proposals As per industry guidance documents 4, the proposals take into account possible further mitigation methods and valid methods of reuse for the excavated peat. On the basis that the initial site investigation indicated a predominately fibrous peat, it is considered likely that excavated peat would be suitable for use in landscaping and restoration activities Proposed peat reuse would therefore comprise: edge dressing and reinstatement alongside site tracks, and around the substation and operations buildings; reinstatement of ground around the turbine foundation excavations using excavation peat to backfill over subsoil, with peat turfs used to dress the surface; and reuse of peat in borrow pit restoration It is anticipated that 1% of the excavated peat or peaty soil would be used on the site in reinstatement around the wind farm infrastructure. Table sets out the estimated volumes and assumption made regarding peat reuse on the site. Table 2.6.2: Estimated Volumes of Peat Reuse (m 3 ) Peat Volume Reused (m 3 ) Assumptions 6, Dressing / reinstatement of track edges, hardstanding edges and edges of substation and operations building platforms. Based on 1m width and.5 m depth on two sides of 6 km of track. 785 Assumes 1% of area of 785 m 3 reused in reinstating the turbine foundation working area excavations 8, Assumes borrow pits can be reinstated using peat dressing to.8 m depth (assuming reinstatement area of 1, m 2 ). Total 14,785 m Summary In summary, the peat probing survey confirmed that there would be relatively low volumes of peat excavated through the construction of the proposed development. The initial assessment of likely excavation volumes indicates approximately 14,779 m 3 would be excavated. It is anticipated that all excavated material would be suitable for reuse based on the shallow depths encountered during the peat probing survey. It is predicted that there would be no excess peat remaining following the reinstatement and restoration activities described. Further detailed analysis of the volumes and proposed reuse of peat would be provided as part of a detailed Stage 2 peat management plan prepared following preconstruction ground investigations. All peat handling and storage would follow industry good practice guidelines. TA 2.6: Peat Management Plan

3 Limited Technical Appendix 2.7: Peat Slide Risk Assessment Introduction Ramboll Environ has been commissioned by Limited to carry out a Peat Slide Risk Assessment for the proposed development. This report forms a technical appendix to the ES This report assesses the potential risk of peat slide at the site as well as providing a precis of the geological and hydrological conditions. The report also outlines suitable mitigation measures, where required, to reduce risks identified. A full description of the proposed development is provided in Chapter 2: Description of the Proposed Development This report represents the findings and opinions of experienced geotechnical and environmental consultants based upon the information obtained from a variety of sources as detailed. Ramboll Environ believes the information obtained from third parties is reliable but does not guarantee its authenticity. The information has been accepted de facto but we have used our professional judgement in its interpretation Objectives of the Study The objectives of the ground stability assessment are to: Undertake a desk top review of available geological, habitat, hydrogeological and topographical information; Review of geological mapping 4 for the site, British Geological Survey (BGS) 1:5, scale; Review of publically available aerial photography and OS aerial imagery; Groundwater Vulnerability map of Scotland 5 ; BGS 1:625, scale hydrogeological map 6 ; Scottish Natural Heritage (SNH) Carbon and Peatland 216 map 7 ; and Site reconnaissance and peat probe field data Site Reconnaissance and Peat Probing A site reconnaissance visit was undertaken by Ramboll Environ between 22nd to 25th February 216 and a follow up visit 6th to 7th October 216 to confirm the desk study findings and OS and aerial photography observations. This was based on the provisional wind farm layout at the time of the surveys, with additional information collated for the remainder of the site where time and access permitted to allow for micrositing A visual assessment of the geological and peat conditions and extents across the site were noted where possible with relevant features such as active, incipient or relict instability recorded. Peat probing was undertaken using probes and auger to identify the thickness of peat deposits The following information was recorded at each peat probe location (where possible): Undertake a site visit to identify evidence of, and potential for, active, incipient or relict peat instability, including identification of the location of features as required; An indication of the nature of the peat, described as fibrous, semi-fibrous or amorphous (based on BS ); Reporting on evidence of any active, incipient or relict peat instability, and the potential risk of future instability, describing the likely causes and contributory factors; A qualitative visual observation of the apparent moisture content of the peat (dry, moist, wet and very wet); and Identify potential controls to be imposed during the construction phase to minimise the risk of any peat instability at the site; and Provide recommendations for further work or specific construction methodologies to suit the ground conditions to mitigate against any increased risk of potential peat instability The assessment has been undertaken in accordance with current Scottish Government guidance on peat landslide hazard and risk assessment for wind farm development 123. An indication of the substrate below the peat, such as bedrock, till, sands and gravels etc Peat Slide Risk Assessment A Peat Slide Risk Assessment was undertaken using a qualitative risk assessment approach based on parameters weighted with reference to engineering professional judgement, field and desk top sources Methodology Desk Study Desk Study Site Location and Setting This report comprises a desk based study and notes compiled from a geo-engineering walkover The site location and setting are described in ES Volume 2: Main Report, Chapter 1: Introduction. survey. The desk study consisted of a review of the available geological and hydrogeological data together with additional information relating to the site including: 1:5, and 1:25, scale Ordnance Survey (OS) topographic mapping; OS Elevation Digital Terrain Mapping (DTM) data; 1 Scottish Executive. 26. Peat Slide Hazard and Risk Assessment: Best Practice Guide for Proposed Electricity Development. 2 Scottish Natural Heritage. 21. Good Practice During Wind Farm Construction. 3 Scottish Government Developments on Peatland: Site Surveys 4 British Geological Survey, Web Map Services (WMS) UK Geology Datasets.[Accessed 21/4/216] Available: 5 Scottish Environment Protection Agency flood map. [Accessed 21/4/216] Available: 6 British Geological Survey, 1:625, scale digital hydrogeological data. [Accessed 21/4/216] Available: 7 Scottish Natural Heritage (SNH) Carbon and Peatland 216 map. Accessed 21/1/216 [online] TA 2.7: Peat Slide Risk Assessment Ramboll Environ

4 Limited Topography and Terrain Analysis The site is undulating comprising forested hill slopes in the west and grassland hill slopes in the east. Hill slopes fall away to the Boyken Burn valley located in the centre of the site which flows from west to east through the site Typical slope angles across the site derived from the Digital Terrain Model (DTM) data and shown in Figure The majority of slopes within the proposed development site are not less than 2 degrees, which is one of the criteria for the 'early exit' route from peat slide risk assessment based on the peat landslide guidance published by the Scottish Government 8. Therefore, a peat slide risk assessment is required for the proposed wind farm development Local Climate The annual average rainfall at the site is approximately 1,395 mm, as provided in the Flood Estimation Handbook (FEH) Peat exhibits highly erratic strength properties and these appear to be linked to water content; shear strength decreases as water content/pore water pressure increases 9. However, the exact mechanism of failure is not always known. While many reported peat failures have been associated with heavy or prolonged rainfall, it should be noted that prolonged periods of heavy rainfall are not necessarily related to instability. In some recorded peat mass movements a dry period has been followed by intense rainfall Both the distribution and intensity of precipitation have a complex influence on the mass movement of peat 1 and rainfall has therefore been considered to be a constant at the site for the risk assessment Superficial Geology The superficial geology is shown in Figure A large proportion of the site is shown on the BGS geological mapping as being absent of superficial deposits, suggesting that bedrock is at or close to the surface. These parts are generally on the higher elevations and steep slopes present at the site. Between the higher areas and steep slopes, the superficial deposits comprise Devensian glacial till (part of the Langholm Till Formation), with smaller areas of alluvium, peat and head deposits also shown Peat deposits are identified in the western and southern parts of the site. Peat probing undertaken by Ramboll Environ confirmed the presence of peat, this largely corresponded to the 1:5, scale BGS geological mapping. Deep peat (in excess of 1.m thickness) was recorded in the west of the site with in a BGS mapped area of peat 11. The maximum depth recorded was 3.8m. Generally, 8 Scottish Executive. 26. Peat Landslide Hazard And Risk Assessments: Best Practice Guide for Proposed Electricity Generation Developments. 9 Lindsay, R.A. and Bragg, O.M. 24. Wind farms and blanket peat. A report on the Derrybrien bogslide. Derrybrien Development Cooperative Ltd, Galway 1 Wilson, P. and Hegarty, C Morphology and Causes of Recent Peat Slides on Skerry Hill, Co. Antrim, Northern Ireland. Earth Surface Processes and Landforms 18, Identified on the BGS 1:5 scale superficial deposits map Ramboll Environ peat was shallow across the remainder of the site and modified within the forestry plantation areas. This is discussed further in Section An extract from the SNH Carbon and Peatland 216 map is shown in Figure 2.7.3; this map indicates the likely presence of carbon-rich soils, deep peat and priority peatland habitat at the site Nationally important resource carbon-rich soils, deep peat and priority peatland habitat and areas likely to be of high conservation value are present in the west and south east of the site although have been avoided through the design of the proposed development. Other areas in the west of the site are identified as carbon rich soils with some areas of deep peat and areas where no peatland habitat is recorded. Mineral soils are identified in the valley within the centre and east of the site Solid Geology The bedrock is described on the BGS geological map as comprising lower Paleozoic (undifferentiated) mudstones and 'Wackes' of Silurian Age (c.42 million years old). Bedrock is sedimentary comprising predominantly calcareous sandstone and siltstone, but occasionally interbedded with mudstone. All sedimentary rocks are thought to be deep sea turbidites Structural Geology BGS mapping indicates there are no faults present within the site boundary. A northeast southwest running fault is located to the north of the site within the Riccarton Group Glacial melt water channel landform features are identified on the 1:5, scale BGS linear features map. Glacial melt water channels within the proposed development site typically flows in an easterly direction Hydrogeology and Hydrology The site is situated within a groundwater Drinking Water Protection Zone (DWPZ), cited for the Eskdale bedrock and localised sand and gravel aquifers 12. However no superficial aquifers are present on the site 13 ; the closest superficial aquifer is Eskdale Sand and Gravel aquifer 14 which is located along the River Esk adjacent to the northeast boundary of the site The bedrock aquifer present on the site is part of the East Dumfriesshire groundwater body The BGS 1:625, scale hydrogeological map indicates that the underlying geology forms low productivity aquifer where the flow is virtually all through fractures and other discontinuities. The aquifer is summarised as highly indurated greywackes with limited groundwater in near surface weathered zone and secondary fractures The OS mapping show that drainage at the proposed development site is generally to the east, with the hillside catchments flowing into Boyken Burn, which in turn flows into the River Esk. The River Esk is cited as a Freshwater Fish Protection Area (River Esk (Border) 16 ). In addition to the natural 12 Eskdale bedrock and localised sand and gravel aquifers Drinking Water Protection Zone - Datasheet. [Accessed 25/4/216] Available: 13 SEPA Environmental Data Water Quality Information - Groundwater. [Accessed 25/4/216] Available: 14 Eskdale Sand and Gravel aquifer Water Body Information Sheet. [Accessed 25/4/216] Available: 15 East Dumfrieshire - Water Body Information Sheet. [Accessed 25/4/216] Available: 16 River Esk (Border) Freshwater Fish Protection Area - Datasheet. [Accessed 25/4/216] Available: TA 2.7: Peat Slide Risk Assessment

5 Limited watercourses on the site, numerous man made drains (comprising shallow ditches) are also present within the conifer plantation. Further detail on the surface water features on the site is provided in Technical Appendix 2.3: Water Crossing Design Two areas of standing water are present on the site. The first is an area of standing water, approximately.3ha in area fed by Yadlairs Sike and Wet Sike (Plate 1) located in the north west of the proposed development site. The second is an area of swamp, located approximately 3 m south of Guttery Gairs (Plate 2) which drains to Auchenbeg Sike. Plate 2: Swamp Which Drains to Auchenbeg Sike (View South) Previous Surveys No relevant previous surveys have been undertaken at the site Geological And Morphological Walkover Survey Plate 1: Standing Water Served by Yadlairs Sike and Wet Sike (View West) Walkover Survey A walkover survey was undertaken to ground truth features noted during the desktop study as well identify any features of note. These included: Geological features, outcrops, slips, landslides etc; Hydrological and hydrogeological features such as springs, surface water etc; Peat features such as evidence of historical or recent peat landslides, cracks, hags, erosion etc; Agricultural and land use features such as drainage channels etc The majority of the site is comprised of dense commercial forestry, access to some of the infrastructure locations was subsequently limited. Much of the site has undergone extensive commercial forestry activities where ground conditions have been worked and reworked which has altered and adversely affected the natural peat conditions Peat deposits were generally located within the flatter parts of the site and no evidence of peat erosion, hags or gullies were noted. TA 2.7: Peat Slide Risk Assessment Ramboll Environ

6 Limited Peat Survey A peat survey was undertaken in February 216 to establish peat depths across the site. The survey was undertaken on an approximate 1-2 m grid to confirm presence of peat identified on the BGS 1:5, scale superficial deposits map, SNH Carbon and Peatland 216 map and presence of peat at proposed turbine locations. Probing along existing estate tracks has only been undertaken at offset locations as penetration through the existing tracks was not possible Peat depths encountered during the survey ranged from m to 3.8 m, the results are provided in Figure and Figure which includes the depth values recorded in the west of the site The survey indicated that across the majority of site surveyed, superficial surface deposits, which predominantly comprised well decomposed peat and peaty organic soils, were <.5 m in depth In Scotland, peat is present where organic soils are greater than.5 m in depth and deep peat is classified at more than 1. m depth The peat deposits in the western part of the proposed development site were recorded more frequently and typically found to be between.5 m and 1. m depth. Occasional isolated, deeper pockets of peat typically between 1. m and 2.5 m were also recorded within these areas. A maximum depth of 3.8 m of peat was recorded within the west of the site, as shown on Figure Deep areas of peat corresponded with peat identified on the BGS 1:5 scale superficial deposits map Peat recorded within forestry plantation areas in the west of the site was found to be highly modified and degraded as a result of the trees and impacts associated with its infrastructure (desiccation effects from drainage associated with rides, tracks etc.) A total of 414 locations were probed. The peat probing exercise informed the design of the site layout and associated infrastructure which avoided peat areas in excess of 1. m in depth The peat depth data from the survey is summarised in Table 2.7.1, this includes all probe locations within the site boundary to demonstrate how the design has evolved to avoid deeper areas of peat. Organic soils of less than.5 m depth are not classified as peat in current guidance and therefore have been screened out of the hazard assessment. Organic soils of less than.5 m depth accounted for 66% of the probed locations. Table 2.7.1: Peat Depths at Probing Locations Peat Depth Range (m Peat Depth Categorisation Number of Locations % of Locations <.5 Organic Soils not classified as Peat Moderate Deep Very Deep > TOTAL 414 1% Ramboll Environ Peat Slide Risk Assessment The assessment adopted the risk analysis methodology outlined within the Scottish Government guidance, where hazard is defined as the likelihood of a peat landslide occurring and exposure is the effect and consequences that the event may have Peat Slide Risk = Hazard x Exposure A qualitative peat landslide hazard assessment has been undertaken using a multi-criteria approach in GIS. The risk bandings have been assigned based on a literature review, professional judgement and experience. Pre-failure Indicators of Instability Pre-failure indicators of instability that are indicative of potential failure in the peat environment at the proposed development site are described in Table below. Table 2.7.2: Instability Feature Observations Reference Observation Peat Depth Range (m) Photo 1 Depression in peat (approximately.5m) close to western boundary where ground plateaus Linear failure on slope (approximately 1-18 degrees) NE-SW for a distance of approximately 15 m.4 TA 2.7: Peat Slide Risk Assessment

7 Limited Table 2.7.2: Instability Feature Observations Table 2.7.2: Instability Feature Observations Reference Observation Peat Depth Range (m) Photo Reference Observation Peat Depth Range (m) Photo 3 Localised slip.6 4 Localised depression on southern boundary where ground plateaus..5 7 Localised slump along edge of plantation. Amorphous peat Depression on southern boundary where ground plateaus..9 8 Linear fissure with slumped Peat on slope (approximately 6-14 degrees) NE- SW.5 No photo. 9 Peat slump on steep slope (approximately degrees) E-W. Pseudo fibrous peat and weathered till exposed in slump..9 6 Depression on slope. Amorphous peat and weathered till exposed in bottom of depression. 1. TA 2.7: Peat Slide Risk Assessment Ramboll Environ

8 Limited Table 2.7.2: Instability Feature Observations Reference Observation Peat Depth Range (m) Photo 1 Slip on steep slope (approximately 1-14 degrees) NW-SE for a distance of approximately 1 m The location of these pre-failure indicators are shown on Figure Pre-failure indicators relating to evidence of movement are described in the perceived risk factor bandings in Table Features included in the assessment comprised historical and recent localised failures, slips, slumps and depressions. No evidence of tension cracks or historical or recent peat landslides was recorded during the walkover survey. A 5 m buffer was applied where pre-failure indicators relating to evidence of movement were recorded and no infrastructure was sited within these areas. Table 2.7.3: Perceived Risk Factors: Movement related pre-failure indicators Movement Indicators Perceived Risk Factor Absent Presence of features indicative of tension, compression or peat creep 1 Presence of historical or recent peat landslides Pre-failure indicators relating to hydrology include proximity to local drainage and connectivity between surface drainage and the peat/impervious interfaces. These are considered to be key characteristics that predispose sites to failure 17 and shear strength tends to decrease as water content/pore water pressure increases 18. Surface watercourse features were identified in the assessment and a 25 m buffer has been applied. Gullies and surface drainage networks included 17 Warburton, J., Holden, J. and Mills, A.J. 24. Hydrological controls of surficial mass movements in peat. Earth-Science Reviews 67, Lindsay, R.A. and Bragg, O.M. 24. Wind farms and blanket peat. A report on the Derrybrien bogslide. Derrybrien Development Cooperative Ltd, Galway Ramboll Environ as part of the forestry and associated land management have been excluded from the assessment. The remainder of the site has been zoned according to the presence or absence of these hydrological pre-failure indicators. These indicators are shown in Table Table 2.7.4: Perceived Risk Factors: Hydrological related pre-failure indicators Hydrological Indicators Perceived Risk Factor Absent Present Presence of glacial till is a potential risk factor, a peat layer overlying an impervious or very low permeability mineral base is considered to be a key factor affecting stability 19. Glacial till was encountered in a small number of probe locations at the peat/mineral base interface during sampling, generally in the south eastern part of the site. Given the low number of probes where glacial till was recorded, and the location, it has been assumed that the majority of the peat at the site is underlain by gravels, likely to be associated with bedrock. The risk factor banding for presence of glacial till is shown in Table Table 2.7.5: Perceived Risk Factors: Presence of Glacial Till Presence of Glacial Till Perceived Risk Factor Absent Present 2 Land Management There is evidence that land management practices can influence the stability of peat. Anthropogenic causes of failure include: Disturbance of the original peat mass by peat cutting, extraction or stockpiling; Pre-forestry ploughing, burning; and Cutting of boundary and drainage ditches The influence of peat drainage is already considered within section 5.1; however other practices are considered in Table below and include peat cutting (influence on stability of face of the peat cutting) and the presence of forestry. This includes all potential effects of forestry on instability, including drainage and desiccation cracks between the forestry furrows and therefore these are not considered separately as pre-failure indicators where forestry is present. Low intensity activities include upland grazing, fallow land and land managed for environmental enhancements or protection There were no areas of peat cutting observed at the site. Forestry covers approximately 89% the site. Table 2.7.6: Perceived Risk Factors: Land Management Land Management Practice Perceived Risk Factor Low intensity activities Peat cutting 1 Forestry standing or felled 2 19 Warburton, J., Holden, J. and Mills, A.J. 24. Hydrological controls of surficial mass movements in peat. Earth-Science Reviews 67, Yang, J. And Dykes, A.P. 26. The liquid limit of peat and its application to the understanding of Irish bog failures. Earth and Environmental Science: Landslides 3, TA 2.7: Peat Slide Risk Assessment

9 Limited Peat Depth Curvature Peat depth is a key factor in peat stability. Typically deeper peat is more humified and amorphous and is potentially weaker, whereas shallow peat tends to have a more fibrous structure and higher shear strength. Peat landslides occur most frequently in peat masses ranging between 1 to 2 m in thickness, while bog bursts commonly occur in peat ranging between 1.5 to 6 m deep The peat depth maps produced from the probe data have been ranked according to Table Organic soils of <.5 m depth are not classified as peat and therefore given a zero risk and screened out of the assessment. The risk factor for deep peat, in excess of 2m, has not been linearly increased as the majority of recorded peat landslides occur in peat depth of 1-2 m 22. Table 2.7.7: Perceived Risk Factors: Peat Depth Published data on the mechanism of peat failure 25 identifies the presence of a convex slope or a slope with a break of slope at its head (concentration of subsurface flow) as being a characteristic that may predispose a location to peat failure. Curvature across the site has been assigned the rankings shown in Table and shown in Figure The ranking is weighted so that the risk increases as the degree of convex curvature increases, as this indicates a sharper break in slope. Table 2.7.9: Perceived Risk Factors: Curvature Curvature Perceived Risk Factor > -.1 (straight and concave) -.1 to -.3 (convex) 1 Peat Depth (m) Land Management Practice Perceived Risk Factor <.5 Thinner bands of peat will have accumulated relatively slowly under a vegetation community dominated by vascular plant species. The roots of these species form a fibrous network within the peat which gives it a high degree of internal coherency These depths of peat will have accumulated relatively rapidly with a greater proportion of Sphagnum (bog-moss) in relation to the vascular taxa. This peat will therefore be less fibrous and more prone to failure due to its relatively amorphous structure. 1 < -.3 (highly convex) 2 Peat Instability Hazard Weighting A weighting has been applied to each of the hazard layers described above to represent its perceived influence on peat stability and to standardise the scoring matrix (Table 2.7.1). The deeper peat (>1 m) and steeper slopes (>5 degrees) are given a higher weighting in the assessment, reflected by the maximum score, as these have been identified as key factors influencing the stability of peat in the previous sections. >1. The thicker the peat, the greater the accumulation rate with proportionally higher amounts of Sphagnum, relative to the abundance of vascular species. The peat is consequently less fibrous and more prone to slippage. In addition, deeper peats are more likely to include weak layers which may cause slip planes and this may be exacerbated further by the presence of semi-fluid pool peat lenses which may cause a high level of instability. Slope The majority of peat landslides occur on slopes of between 5-2 degrees and slopes for bog bursts typically range between 2-8 degrees 23. The site topography slope degrees have been classified according to the factors assigned in Table The Scottish Government guidance suggests that over 95% of published peat failures are situated on slopes >2 degrees unless triggered by a profound anthropogenic mechanism and therefore slopes <2 degrees are given a zero ranking. The same risk factor is applied to all slopes >5 degrees following the evidence that the majority of failures occur on slopes between 5-2 degrees. It should be noted that the accumulation of significant peat depths is generally limited to slopes of <2 degrees 24. Table 2.7.8: Perceived Risk Factors: Slope Slope Perceived Risk Factor <2 o 2-5 o 1 >5 o 3 3 Table 2.7.1: Peat Instability Hazard Weightings Pre-condition to Peat Instability Perceived Risk Factor Range Weighting Maximum Score Pre-failure indicators movement Pre-failure indicators hydrology Pre-failure indicators presence of glacial till Land management Peat depth Slope Curvature Maximum score This scoring methodology has then been used to band the peat instability hazard across the site in line with Scottish Government best practice guidance, as summarised in Table Table : Peat Instability Hazard Scale Hazard Perceived Hazard Range 5 High >18 4 Medium High Medium Medium Low Low Evans, M.G. and Warburton, J. 21. Geomorphology of Upland Peat: Erosion, Form and Landscape Change 24 Hobbs, N. B Mire morphology and the properties and behaviour of some British and foreign peats. Quarterly Journal of Engineering 22 Evans, M.G. and Warburton, J. 21. Geomorphology of Upland Peat: Erosion, Form and Landscape Change Geology 19, Evans, M.G. and Warburton, J. 21. Geomorphology of Upland Peat: Erosion, Form and Landscape Change 25 Warburton, J., Holden, J. and Mills, A.J. 24. Hydrological controls of surficial mass movements in peat. Earth-Science Reviews 67, TA 2.7: Peat Slide Risk Assessment Ramboll Environ

10 Limited The peat instability hazard map for the site is shown in Figure Any blank areas represent areas where peat depth is less than.5m and which have therefore been screened out of the assessment Key findings from the hazard maps include: Movement indicator features were recorded in areas where the topography plateaus along the southern and western boundary and in areas where there are steep slopes in the south east of the site (Figure 2.7.6); All of the proposed infrastructure lies outside areas of deep peat (>1. m) (Figure 2.7.5); Of the infrastructure sited on peat, the following features are located within zones of medium low and medium hazard: Proposed new access track for T1 and T2 and associated foundations and temporary hardstanding (predominately medium low hazard); Approximately 2 m of the proposed new access track for T3 (from the existing track to the T3 location), (predominately medium low hazard, however there is an zone of medium high risk to the west of the proposed new access track to T3); Proposed new access track for T4 and associated foundations and temporary hardstanding (predominately medium hazard); Approximately 13 m Proposed new access track for T5 and associated foundations and part of the temporary hardstanding ; Turning area situated between T8 and T1 and the section of the proposed new access track at this turning area (predominately medium low hazard, a zone of medium high hazard is present below this location); and Approximately 19 m of the proposed new access track for T9 (medium hazard, a zone of medium high hazard is present above this location); A small area of the temporary storage area hardstanding falls within a medium hazard zone, and some very small sections of the infrastructure pass though small areas identified as a medium high hazard; and No infrastructure passes through a high hazard zone Note, areas where the existing estate tracks intersect risk zones have been excluded. Exposure An assessment of the effect and consequence of any peat landslide event is undertaken by assessing the potential exposure. Peat failure in the wind farm area could have the following key consequences: Risk of injury of death to site workers; Damage to wind farm infrastructure, including turbines, tracks and plant; Damage to local properties; Pollution of local watercourses and potential alteration of drainage patterns due to blockage; Damage to habitats (including aquatic habitats); and Risk of blockage to local roads and transport links There is considerable uncertainty in defining the potential magnitude of impacts of a peat landslide as this will depend on the precise location of the slide, the volume of peat mobilised and the runout distance and velocity. The approach presented in Table and shown in Figure is based on the sensitivity of the likely receptors. Ramboll Environ The PSRA extent was split into sub-areas based on presence of peat and local topography to identify the likely receptors. This procedure does not factor in likely volumes or distance that a slide may travel, and given that the peat masses at this site are generally localised in extent or located on flatter ground, the exposure scores are considered to be conservative. The exposure has been defined only for the peat deposits <1. m, on the basis that peat landslides occur most frequently in peat masses ranging between 1. to 2. m in thickness (i.e. no exposure score is assigned for areas where peat depth <1. m) The majority of the peat masses have been assessed as having medium or medium low exposure, depending upon whether there is the potential to affect site infrastructure. It is assumes all watercourses on site are classified as minor watercourses. Table : Exposure and Effects Scale Exposure Likely Consequences 5 High Potential to damage property; and/ or Potential to directly impact on water bodies used for drinking water provision; and/ or Potential to directly affect internationally designated sites (e.g. SAC/ SPA). 4 Medium High Potential to damage public roads/ transport links; and/ or Potential to directly impact on main watercourses (i.e. those classified under WFD); and/ or Potential to directly affect nationally designated sites (e.g. SSSI). 3 Medium Potential to damage site infrastructure (and associated risk to site workers); 2 Medium Low Potential to directly impact minor watercourses (& therefore indirectly on main watercourses). 1 Low Direct impacts limited to localised damage of terrestrial habitats or water bodies with limited ecological value. Peat Slide Risk The peat instability hazard and exposure scores have been multiplied to produce a peat landslide risk ranking between 1 25 as shown in Table and Figure Table : Peat Slide Risk Ranking Scale Risk Ranking Proposed Actions Serious Avoid project development at these locations Substantial Project should not proceed unless the hazard can be avoided or mitigated at these locations, without significant environmental effects, in order to reduce hazard ranking to significant or less. 5-1 Significant Project may proceed pending further investigation to refine assessment and mitigate hazard through re-location or re-design at these locations. 1-4 Insignificant Project should proceed with monitoring and mitigation of peat land landslide hazards at these locations as appropriate No proposed infrastructure falls within the area identified to pose a peat slide risk, however the following areas are directly adjacent to significant and substantial zones of peat slide risk: To the west of T3 is a zone of significant peat slide risk, the slope is approximately 2-5 degrees and peat depths recorded in the range.9 m to 2. m within 1m of the proposed infrastructure at this location; To the west of approximately 2 m of the proposed new access track for T3 (from the existing track to the T3 location) is a zone of significant and substantial peat slide risk, the slope is TA 2.7: Peat Slide Risk Assessment

11 Limited approximately 5-1 degrees and peat depths recorded in the range of.9 m to 2. m within 1m of the proposed infrastructure at this location; To the north east of approximately 19 m of the proposed new access track for T9 is a zone of significant and substantial peat slide risk (above the track), the slope is approximately 5-1 degrees and peat depths recorded in the range of.1 m to 2.4 m within 1m of the proposed infrastructure at this location; To the west of the turning area for T9 is a zone of significant peat slide risk, the slope is approximately 2-5 degrees and peat depths recorded in the range of.5 m to 1.7 m within 1m of the proposed infrastructure at this location; To the south of approximately 7 m of the proposed new access track for T1 is a zone of significant and substantial peat slide risk (below the track), the slope is approximately 5-1 degrees and peat depths recorded in the range of. m to 1.7 m within 1m of the proposed infrastructure at this location; and At the existing track location south east of T5 is a zone of significant peat slide risk (above and below the existing track), the slope is approximately 2-5 degrees and peat depths recorded in the range of.8 m to 1.1 m within 1m of the proposed infrastructure at this location Although no proposed infrastructure falls within areas identified to pose a peat slide risk, suitable mitigation, monitoring and contingency measures would be put in place (section 6) as some infrastructure is adjacent to areas which pose a risk. The overall residual risk of peat landslide during the operational phase is considered to be low Mitigation Measures And Construction Considerations The third relates to the adverse concentration of water flows within a slope or into unstable excavations. These matters are discussed below. A Geotechnical Risk Register will need to be completed as part of the design phase to discuss these issues in more detail. Head Loading Concentrated loads, such as excavated material placed on the slope, create the single most adverse negative short-term effect on the stability of a slope. The significance of this can be moderate. Accordingly, during the construction phase, all excavated materials should be removed to temporary storage mounds positioned at safe slope gradients and certified by a geotechnical engineer Loading associated with the construction of floating tracks may lead to unstable ground conditions. Accordingly, all tracks will be, as far as possible, constructed under geotechnical supervision and monitored during and after construction. No floating tracks are proposed as part of the scheme. Removal of Toe Support Excavation of the slope for turbine foundations or for excavated tracks may remove toe support and increase potential for ground movements. The earthworks and any excavation should be designed and undertaken in such a way as to avoid any excavation of toe support material. The excavation of any temporary slopes should be fully designed. Adverse Concentration of Water Flows Disturbance to the natural drainage system may increase potential for peat instability. Therefore, the design of any new drainage should be undertake to ensure no adverse loading is placed on areas of marginal peat stability. General The design of the proposed development has avoided deep peat (i.e. >1m in depth). Specific mitigation measures required to minimise the potential effects from peat slide and on peat as a resource is described below. Turbines Whilst turbines have been sited to avoid areas of deep peat, micrositing will be used during the detailed design and construction phases to further avoid areas of peat or other high risk areas. This would be undertaken under the direction of a geotechnical engineer. s The only part of the wind farm that is located in peat deeper than 1m is the existing track located between T4 and T5. It is proposed that the existing track is widened to accommodate the construction traffic but it is considered that the peat is likely to be highly modified given the existing forestry land use Tracks can also be microsited to avoid the need for localised cut and fill, particularly on convex slopes Since peat sliding almost invariably involves increased pore water pressures, it follows that robust drainage plans and engineering control of water during the development should result in a significant overall reduction in the risk of peat instability. Other Peat slide potential also increases with: Rockhead smoothness; Clayey subsoils that impede water flows and provide smooth slip-surfaces; Localised steep gradients; Presence of solifluction planes; Incorrectly designed drainage works that may have a negative effect; and Localised erosion features such as animal paths and stream channels Accordingly, construction activities should be carried out under geotechnical supervision, as required, and protection measures should be implemented using an observational method of continued, managed and integrated design, construction, monitoring and review. Geotechnical Risk Register Construction Effects Although the ground conditions at the site are considered to be favourable for development purposes, the potential short-term negative effects relating to the construction of the windfarm that might influence peat stability need to be considered. The first potential effect involves concentrated loads, such as material from turbine foundation excavations, being placed on marginally stable ground at the top of a slope. The second involves removal of toe support at the bottom of a slope It is recommended that a system of geotechnical risk management is adopted during the detailed engineering design and construction phases of the proposed wind farm as a key element in the TA 2.7: Peat Slide Risk Assessment Ramboll Environ

12 Limited overall risk assessment for the project (Clayton, 21) 26. A geotechnical risk register for the proposed development will be undertaken as part of the detailed design. This may be used to demonstrate that geotechnical risk may be properly controlled, kept under review and further reduced as and when possible, as well as to demonstrate that geotechnical risk management has commenced It should be noted that the geotechnical risk register is a live document and once commenced is continued through to project completion. Regular reviews of existing risks as well as the addition of newly discovered risks re incorporated in the register. Control Measures The design and construction process incorporates methods for preventing peat slides or minimising their effects. The various methods either prevent peat masses from moving out of place or protect sensitive site by keeping peat masses that do move out of place from reaching a target site. These methods include: Limited duration improvements to remove loose blocks or masses of peat; Earthworks to create interception ditches; Minor modifications to track alignments to avoid difficult ground; Drainage works to collect or divert uncontrolled water flows; Installation of multi-rows of recycled plastic pin-piles; Installation of arrays of plate piles; Gabion barrier walls to apply direct support to a peat face; Rockfill buttressing to provide support for large masses of unstable peat; and Channel training works such as ditch deepening and reshaping to mitigate erosion Where turbines cannot be microsited out of a medium peat slide risk area, they will require a combination of the above measures to ensure that the stability of the peat is maintained through the construction process The excavation for turbine bases and crane hardstandings should be kept to a minimum, but it is likely that the necessary suitable founding stratum will be at least 1m below the base of the peat. The soft and compressible nature of the peat means that unsupported cut or excavated slopes may be unstable unless suitable geotechnical design is undertaken and appropriate engineering control measures put in place. The overall width of such an excavation at formation level could be up to 2 m and over 3 m at the original ground surface. Therefore in areas of deep peat, a design shall be produced by an experienced peat geotechnical engineer that minimises risk and the extent of excavation and reduces the requirement for dewatering and peat disposal For the construction of access tracks it is important that construction methods do not disrupt the established drainage and that no areas are surcharged by water discharge or spoil. In general the following principles should be adopted: Long sections of access track in areas of peat greater than 2. m should be of floating type construction and an allowance should be made for their long term maintenance as a result of on-going settlement. Where more local or isolated areas of peat >2. m are crossed, it will be preferable to locally microsite the track or proceed on the basis of a more detailed design; Construction of tracks parallel or perpendicular to slope contours, but avoidance of obliquely crossing slope contours where detailed cut and fill operations may be required. 26 Clayton, C. 21. Managing geotechnical risk: improving productivity in UK building and construction Ramboll Environ Where floating tracks are not constructed excavation down to a suitable founding stratum for the track should be undertaken; The existing drainage is critically important therefore all existing drainage routes should be maintained and where necessary, channelled below the proposed route. Upslope drainage ditches will be required and constructed with cross drains so water can pass freely across the carriageway at regular intervals. This will also prevent erosion in side ditches due to their capacity being exceeded and concentration of water on the down slope area; The camber of the track should be constructed to encourage water to drain an appropriate trackside drainage ditch; and Track gradients should be maintained at appropriate gradient to allow access for the typical range of construction traffic expected It is likely there will be a requirement of access tracks to cross a number of minor watercourses at the site. In general, culverted crossings are considered to be most appropriate for such crossings due to their ease of construction and reduced environmental impact compared to traditional bridge type structures Flexible, corrugated, galvanised steel or plastic culverts are considered to be better suited to these conditions than rigid concrete box culverts as they are easier to handle and do not require immediate access from both sides of the watercourse. Such flexible culverts would be suitable for all minor stream and ditch crossings and founded on suitable engineered bedding material to provide conformity of settlement between the culvert and the approach structure. Some differential settlement can be accommodated with localised back filling A programme of regular inspection and maintenance will be required during the construction period and throughout the life cycle of the wind farm before any significant movement of infrastructure is undertaken Where crossing spans are larger, it may be possible to construct several culverts adjacent to each other, use a larger reinforced concrete box culvert or revert to a bridge structure. Stockpiles Excavation of peat at locations of proposed turbines, new tracks and other infrastructure could potentially result in storage of soils, including peat. There is extensive guidance with regard to the procedures for the design and construction of subsoil storage mounds. The design and construction of the subsoil storage mounds should be undertaken and supervised by a geotechnical engineer and carried out in accordance with current good practice guidance Conclusions and Recommendations A qualitative peat slide risk assessment has been undertaken for the proposed development. This has been undertaken based on a multi criteria, GIS based approach, using both desk and field based data Peat was generally found to be either absent or shallow across the majority of the proposed development site. The majority of the peat deposits were identified in the western and southern parts of the proposed development site, which generally corresponded with the published BGS geological mapping. TA 2.7: Peat Slide Risk Assessment

13 Limited Deep peat (in excess of 1.m thickness) was recorded in the western part of the site, where the maximum peat thickness recorded was 3.8m. Generally, peat was shallow across the remainder of the site and found to be highly modified within the forestry plantation areas, which occupy the majority of the site None of the proposed wind farm infrastructure was found to be located in areas identified as a peat slide risk, however the following areas were identified as being located directly adjacent either to insignificant or to significant and substantial zones of peat slide risk: To the west of T3 is a zone of significant peat slide risk, the slope is approximately 2-5 degrees and peat depths recorded in the range of.9 m to 2. m within 1m of the proposed infrastructure at this location; To the west of approximately 2 m of the proposed new access track for T3 (from the existing track to the T3 location) is a zone of significant and substantial peat slide risk, the slope is approximately 5-1 degrees and peat depths recorded in the range of.9 m to 2. m within 1m of the proposed infrastructure at this location; To the north east of approximately 19 m of the proposed new access track for T9 is a zone of significant and substantial peat slide risk (above the track), the slope is approximately 5-1 degrees and peat depths recorded in the range of.1 m to 2.4 m within 1m of the proposed infrastructure at this location; To the west of the turning area for T9 is a zone of significant peat slide risk, the slope is approximately 2-5 degrees and peat depths recorded in the range of.5 m to 1.7 m within 1m of the proposed infrastructure at this location; To the south of approximately 7 m of the proposed new access track for T1 is a zone of significant and substantial peat slide risk (below the track), the slope is approximately 5-1 degrees and peat depths recorded in the range of. m to 1.7 m within 1m of the proposed infrastructure at this location; and At the existing track location south east of T5 is a zone of significant peat slide risk (above and below the existing track), the slope is approximately 2-5 degrees and peat depths recorded in the range of.8 m to 1.1 m within 1m of the proposed infrastructure at this location Both the insignificant and significant zones are considered acceptable for development, assuming that mitigation and good practice is used as some infrastructure is adjacent to areas which pose a risk, although it is considered to be low Mitigation measures recommended include the use of micrositing of wind farm infrastructure following ground investigation, on site supervision by a geotechnical engineer during construction as well as use of standard geotechnical and environmental good practice during construction to minimise additional loading on peat (e.g. locating stockpiles of materials away from sensitive areas). These will be documented as part of a Construction Environmental Management Plan (CEMP), which will also include reference to a peat management plan. TA 2.7: Peat Slide Risk Assessment Ramboll Environ

14 Limited Appendix A: Figures Figure 2.7.1: Slope Angles Figure 2.7.2: Superficial Deposits Figure 2.7.3: SNH Carbon and Peatland 216 map Figure 2.7.4: Peat Survey Results Figure 2.7.5: Peat Survey Results and Probe Locations Figure 2.7.6: Peat Failure (movement) Indicators Figure 2.7.7: Curvature Profile Figure 2.7.8: Peat Slide Hazard Figure 2.7.9: Peat Instability Exposure Figure 2.7.1: Peat Slide Risk Ramboll Environ TA 2.7: Peat Slide Risk Assessment

15 Reproduced from Ordnance Survey Map Data with the permission of the Controller of HMSO, Crown Copyright Reserved Licence No. ES T7 T6 T8 T5 T9 T4 T3 T2 T1 1, Meters T1 T11 T12 Key N Site Boundary Turbine Location Proposed New Site Proposed Upgrade of Existing Site Site Slope Degrees >15 Title Figure 2.7.1: Slope Angles Project No. UK Site Langholm Client Ltd Date December 216 Scale A3 1 HN Issue Drawn by Path: \\vulture\projects\162125\analysis\gis\mxd\figure_mxds\peat Slide Risk Assessmnent\Figure 2 Site Slope Angles.mxd

16 Reproduced from Ordnance Survey Map Data with the permission of the Controller of HMSO, Crown Copyright Reserved Licence No. ES T7 T6 T8 T5 T4 T9 T3 T2 T1 1, Meters T1 T11 T12 Key N Site Boundary Turbine Location Proposed New Site Proposed Upgrade of Existing Site Peat (BGS 5k Superficial deposits) Glacial Till (BGS 5k Superficial deposits) Alluvium (BGS 5k Superficial deposits) Head Deposits (BGS 5k Superficial deposits) Kirkbean Sand and Gravel (BGS 5k Superficial deposits) River Terrace Deposits (BGS 5k Superficial deposits) Contains British Geological Survey materials NERC 216 Title Figure 2.7.2: Superficial Deposits Project No. UK Site Langholm Client Ltd Date December 216 Scale A3 1 HN Issue Drawn by Path: \\vulture\projects\162125\analysis\gis\mxd\figure_mxds\peat Slide Risk Assessmnent\Figure 3 Superficial Geology.mxd

17 Reproduced from Ordnance Survey Map Data with the permission of the Controller of HMSO, Crown Copyright Reserved Licence No. ES T7 T6 T8 T5 T4 T9 T3 T2 T1 1, Meters T1 T11 T12 Key N Site Boundary Turbine Location Proposed New Site Proposed Upgrade of Existing Site Carbon and Peatland 216 Map Mineral soils (Peatland habitats are not typically found on such soils) Class 1 Carbon-rich soils and deep peat Most soils are carbon-rich soils, with some areas of deep peat No peatland habitat recorded. May also show bare soil. Contains information obtained from Scottish Natural Heritage 216 Title Figure 2.7.3: SNH Carbon and Peatland 216 map Project No. UK Site Langholm Client Ltd Date December 216 Scale A3 1 HN Issue Drawn by Path: \\vulture\projects\162125\analysis\gis\mxd\figure_mxds\peat Slide Risk Assessmnent\Figure 4 SNH Carbon and Peatland map.mxd

18 Reproduced from Ordnance Survey Map Data with the permission of the Controller of HMSO, Crown Copyright Reserved Licence No. ES T7 T6 T8 T5 T1 T4 T9 T3 T2 T1 1, Meters T11 T12 Key N Site Boundary Turbine Location Proposed New Site Proposed Upgrade of Existing Site Turning Area Turbine Substation Site Entrance Temporary Storage Area Temporary Site Facilities Borrow Pit Search Areas Peat depth (m) Title Figure 2.7.4: Peat Survey Results Project No. UK Site Langholm Client Ltd Date Scale December 216 A3 1 HN Issue Drawn by Path: \\vulture\projects\162125\analysis\gis\mxd\figure_mxds\peat Slide Risk Assessmnent\Figure 5 Peat Survey Results.mxd

19 Reproduced from Ordnance Survey Map Data with the permission of the Controller of HMSO, Crown Copyright Reserved Licence No. ES T T T T T1 T T T T T T T , Meters Key N Site Boundary Turbine Location Proposed New Site Proposed Upgrade of Existing Site Turning Area Turbine Substation Site Entrance Temporary Storage Area Temporary Site Facilities Borrow Pit Search Areas Peat depth (m) Peat depth (m) Title Figure 2.7.5: Peat Survey Results and Probe Locations Project No. UK Site Langholm Client Ltd Date Scale December 216 A3 1 HN Issue Drawn by Path: \\vulture\projects\162125\analysis\gis\mxd\figure_mxds\peat Slide Risk Assessmnent\Figure 2.7.5_Peat Survey Results incl. depths.mxd

20 Reproduced from Ordnance Survey Map Data with the permission of the Controller of HMSO, Crown Copyright Reserved Licence No. ES T7 T6 T8 T5 T1 T4 T9 1 T3 T2 3 2 T , Meters 6 T11 T Key N Site Boundary Turbine Location Proposed New Site Proposed Upgrade of Existing Site Turning Area Turbine Substation Site Entrance Temporary Storage Area Temporary Site Facilities Borrow Pit Search Areas ( Peat Failure (movement) Indicators Peat depth (m) Title Figure 2.7.6: Peat Failure (movement) Indicators Project No. UK Site Langholm Client Ltd Date Scale December 216 A3 1 HN Issue Drawn by Path: \\vulture\projects\162125\analysis\gis\mxd\figure_mxds\peat Slide Risk Assessmnent\Figure 2.7.6_Peat Movement References.mxd

21 Reproduced from Ordnance Survey Map Data with the permission of the Controller of HMSO, Crown Copyright Reserved Licence No. ES T7 T6 T5 T4 T3 T2 T1 1, Meters T8 T9 T1 T11 T12 Key N Site Boundary Turbine Location Proposed New Site Proposed Upgrade of Existing Site Turning Area Curvature Profile < -.3 (Highly convex) (Convex) (Straight) (Concave).3-3 (Highly concave) Title Figure 2.7.7: Curvature Profile Project No. UK Site Langholm Client Ltd Date Scale December 216 A3 1 HN Issue Drawn by Path: \\vulture\projects\162125\analysis\gis\mxd\figure_mxds\peat Slide Risk Assessmnent\Figure 2.7.7_Curve.mxd

22 Reproduced from Ordnance Survey Map Data with the permission of the Controller of HMSO, Crown Copyright Reserved Licence No. ES T7 T6 T5 T4 T3 T2 T1 1, Meters T8 T9 T1 T11 T12 Key N Site Boundary Turbine Location Proposed New Site Proposed Upgrade of Existing Site Turning Area Turbine Substation Temporary Storage Area Temporary Site Facilities Borrow Pit Search Areas Peat Slide Hazard 1 (Low) 2 (Medium Low) 3 (Medium) 4 (Medium High) 5 (High) Title Figure 2.7.8: Peat Slide Hazard Project No. UK Site Langholm Client Ltd Date Scale December 216 A3 1 HN Issue Drawn by Path: \\vulture\projects\162125\analysis\gis\mxd\figure_mxds\peat Slide Risk Assessmnent\Figure 2.7.8_Hazard.mxd

23 Reproduced from Ordnance Survey Map Data with the permission of the Controller of HMSO, Crown Copyright Reserved Licence No. ES T7 T6 T5 T4 T3 T2 T1 1, Meters T8 T9 T1 T11 T12 Key N Site Boundary Turbine Location Proposed New Site Proposed Upgrade of Existing Site Turning Area Turbine Substation Temporary Storage Area Temporary Site Facilities Borrow Pit Search Areas Peat Instability Exposure 1 (Low) 2 (Medium Low) 3 (Medium) Title Figure 2.7.9: Peat Instability Exposure Project No. UK Site Langholm Client Ltd Date Scale December 216 A3 1 HN Issue Drawn by Path: \\vulture\projects\162125\analysis\gis\mxd\figure_mxds\peat Slide Risk Assessmnent\Figure 2.7.8_Exposure.mxd

24 Reproduced from Ordnance Survey Map Data with the permission of the Controller of HMSO, Crown Copyright Reserved Licence No. ES T7 T6 T5 T4 T3 T2 T1 1, Meters T8 T9 T1 T11 T12 Key N Site Boundary Turbine Location Proposed New Site Proposed Upgrade of Existing Site Turning Area Turbine Substation Temporary Storage Area Temporary Site Facilities Borrow Pit Search Areas Peat Slide Risk 1-4 (Insignificant) 5-1 (Significant) (Substantial) (Serious) Title Figure 2.7.1: Peat Slide Risk Project No. UK Site Langholm Client Ltd Date Scale December 216 A3 1 HN Issue Drawn by Path: \\vulture\projects\162125\analysis\gis\mxd\figure_mxds\peat Slide Risk Assessmnent\Figure 2.7.1_Risk.mxd

25 Limited Technical Appendix 2.8: Carbon Balance Assessment Introduction Table 2.8.1: Data Input Sources This Technical Appendix provides a carbon balance assessment for the proposed ( the proposed development. The carbon balance has been calculated by comparing the carbon costs of the wind farm with the potential carbon savings. Input data Source Backup Extra capacity required for backup (%) Dale et al The carbon balance assessment has been undertaken using the Scottish Government s Carbon Calculator Tool (version 2.9.), the last version to be published as an MS Excel spreadsheet. This was based on the research undertaken by Nayak et al (28 and 21) A new carbon calculator (C-CalcWebV1.) was released by the Scottish Government in June 216 which uses an online, web based system. It is the intention that all new applications to the Scottish Government Energy Consents Unit will use this new tool. As the new carbon calculator is an online tool, it is automatically issued to the Energy Consents Unit and Scottish Environmental Protection Agency (SEPA) As the planning application for the will not be made to the Energy Consents Unit (as it is <5MW capacity), it is not mandatory to use the Scottish Government s carbon calculator. It is however, considered good practice to do so. As the application will be made to Dumfries and Galloway Council, the previous version of the calculator was considered appropriate to use. Additional emissions due to reduced thermal efficiency of the reserve generation (%) Carbon dioxide emissions from turbine life - (eg. manufacture, construction, decommissioning) Dale at al 24 Fixed Characteristics of peatland before windfarm development Type of peatland Acid bog Average annual air temperature at site ( o C) Annual Temperature at Eskdalemuir: Average depth of peat at site (m) Values from the Peat Probing exercise undertaken by Ramboll Environ in 216 and results presented using GIS Analysis C Content of dry peat (% by weight) An estimate of the range of %C in peat of between 49% and 62% is provided by Birnie et al. (1991) and has been used in this occasion Forestry has not been included as part of the assessment on the basis that the plantation at the site is a commercial crop and is intended to be felled regardless of the construction and operation of the wind farm The carbon balance payback section of the carbon calculator is provided in Appendix 1. The full carbon calculator is available on request. Average extent of drainage around drainage features at site (m) Expected value provided, based on professional judgement. This is a conservative estimate (i.e. drainage effects are likely to be less than this) based on the drained / afforested nature of the site meaning the site is already significantly impacted by forestry drainage and hence water table levels are artificially low. Average water table depth at site (m) SEPA recommended values used (Same Values were used for other local schemes ) Input Data The data used to inform the carbon calculator was mostly sourced from the details contained within the (such as the project description, hydrology and ground conditions). Where specific parameters were not available, default values were included as suggested by the carbon calculator methodology. These are shown below in Table below, the full carbon calculator datasheet is available on request. Table 2.8.1: Data Input Sources Input data Source Windfarm characteristics Dimensions No. of turbines Chapter 2: Project Description and Team Briefing Note (UK _3_Briefing Note.pdf) Lifetime of windfarm (years) Fixed Performance Power rating of turbines (turbine capacity) (MW) Chapter 2: Project Description and Team Briefing Note (UK _3_Briefing Note.pdf) Capacity factor Fixed based on DECC Energy Trends 216, /file/386812/et_dec_14.pdf, Table 6.1, Page 47 (213 capacity factor) Dry soil bulk density (g cm-3) Default generic values from the National Soil Inventory of Scotland (27-29) used: Characteristics of bog plants Time required for regeneration of bog plants after restoration (years) Carbon accumulation due to C fixation by bog plants in undrained peats (tc ha-1 yr- 1) Forestry Plantation Characteristics Method used to calculate CO2 loss from forest felling Area of forestry plantation to be felled (ha) Average rate of carbon sequestration in timber (tc ha-1 yr-1) Counterfactual emission factors Minimum:.72 Maximum:.293 Mean:.132 Note: spreadsheet only shows to two decimal places) Regeneration of bog plants after the initiation of restoration can take 1-4 years, depending on the state of the modified bog. It has been assumed that 1 years is considered appropriate based on the habitats present which are mostly within existing forest rides. SNH Technical Guidance Note (23) on Wind Farms and Carbon Savings N/A Assumed that no forestry to be felled as based on commercial crop at site. SNH Technical Guidance Note as mentioned in the comment TA 2.8: Carbon Balance Assessment Ramboll Environ

26 Limited Table 2.8.1: Data Input Sources Input data Source Coal-fired plant emission factor (t CO2 MWh-1) Digest of United Kingdom, Energy Statistics /file/5526/dukes_216_final.pdf Grid-mix emission factor (t CO2 MWh-1) Digest of United Kingdom, Energy Statistics /file/5526/dukes_216_final.pdf Fossil fuel-mix emission factor (t CO2 MWh-1) Digest of United Kingdom, Energy Statistics /file/5526/dukes_216_final.pdf Borrow pits Number of borrow pits ES Technical Appendix 2.4: Borrow Pit Assessment Report Average length of pits (m) ES Technical Appendix 2.4: Borrow Pit Assessment Report Average width of pits (m) ES Technical Appendix 2.4: Borrow Pit Assessment Report Average depth of peat removed from pit (m) Value based on desk-based assessment, site walkover and peat probing undertaken by Ramboll Environ (ES Technical Appendix 2.4 Borrow Pit Assessment Report). Average calculated by evaluating peat probe data at locations within and adjacent borrow pit search areas. Foundations and hard-standing area associated with each turbine Method used to calculate CO2 loss from foundations and hard-standing Fixed Average length of turbine foundations (m) Indicative Turbine Foundation and Crane and GIS Analysis Average width of turbine foundations (m) Indicative Turbine Foundation and Crane and GIS Analysis Average depth of peat removed from turbine foundations (m) ES Technical Appendix 2.7: Peat Slide Risk Assessment and GIS Analysis Average length of hard-standing (m) ES Technical Appendix 2.7: Peat Slide Risk Assessment and GIS Analysis Average width of hard-standing (m) ES Technical Appendix 2.7: Peat Slide Risk Assessment and GIS Analysis Average depth of peat removed from hard-standing (m) ES Technical Appendix 2.7: Peat Slide Risk Assessment and GIS Analysis Access tracks Total length of access track (m) Chapter 2: Proposed Development and GIS Analysis Existing track length (m) Chapter 2: Proposed Development and GIS Analysis Length of access track that is floating road (m) Floating road width (m) Chapter 2: Proposed Development and GIS Analysis Floating road depth (m) Chapter 2: Proposed Development and GIS Analysis Length of floating road that is drained (m) Chapter 2: Proposed Development and GIS Analysis Average depth of drains associated with floating roads (m) Chapter 2: Proposed Development and GIS Analysis Length of access track that is excavated road (m) Chapter2: Proposed Development and GIS Analysis Excavated road width (m) Chapter 2: Proposed Development and GIS Analysis Ramboll Environ Table 2.8.1: Data Input Sources Input data Source Average depth of peat excavated for road (m) Assumed (zero) m Length of access track that is rock filled road (m) Rock filled road width (m) Rock filled road depth (m) Length of rock filled road that is drained (m) Average depth of drains associated with rock filled roads (m) Cable Trenches Length of any cable trench on peat that does not follow access tracks and is lined with a permeable medium (eg. sand) (m) Values are based on peat depths recorded during peat probing along the route of the proposed access tracks. Minimum and maximum values are also provided, based on the results of the peat probing and the depth of the cable trench. Average depth of peat cut for cable trenches (m) Based on professional experience (Glencassley, Inverclyde and Hadyard Hill) Additional peat excavated (not already accounted for above) Volume of additional peat excavated (m3) Values for volume of additional peat excavated in relation to the temporary site facilities/compound, substation and temporary storage area have been taken from the following sources: Peat Slide Risk Assessment; and Chapter 2: Proposed Development The volumes of additional excavated peat are as follows: Temporary Storage Area 676.5m 3 (1,5m 2 x.45m); Temporary Site Facilities - 2,74 m 3 (5m 2 x.41m); Substation 2,418.8 m 3 (75m 2 x.32m); and Site Entrance.84 m 3 (14m 2 x.m); Area of additional peat excavated (m2) Values for area of additional peat excavated have been provided based on the information sources referenced in the row above in relation to the temporary construction compound, concrete batching plant, substation and operations buildings and met masts. Temporary Storage Area 1,5 m 2 ; Temporary Site Facilities/compound - 5,m 2 ; Substation 7,5 m 2 ; and Site Entrance 1,4 m 2 ; Improvement of C sequestration at site by blocking drains, restoration of habitat etc. Improvement of degraded bog Area of degraded bog to be improved (ha) Habitat restoration measures are included within the outline Habitat Management Plan (Technical Appendix 5.7). The assumptions used are that areas with peat depth >1m will be restored to blanket bog, peat depth.5m to 1m will be restored to blanket bog and wet heath mosaic and areas.m to.5m restored to wet/dry heath and marshy grassland mosaic. Assumed a buffer of 1m around turbine locations, 1m buffer for new access tracks and 2.5m around new hardstanding areas. Water table depth in degraded bog before improvement (m) Water table depth in degraded bog after improvement (m) TA 2.8: Carbon Balance Assessment

27 Limited Table 2.8.1: Data Input Sources Table 2.8.1: Data Input Sources Input data Source Input data Source Time required for hydrology and habitat of bog to return to its previous state on improvement (years) Period of time when effectiveness of the improvement in degraded bog can be guaranteed (years) Improvement of felled plantation land Area of felled plantation to be improved (ha) Water table depth in felled area before improvement (m) Water table depth in felled area after improvement (m) Time required for hydrology and habitat of felled plantation to return to its previous state on improvement (years) Period of time when effectiveness of the improvement in felled plantation can be guaranteed (years) Restoration of peat removed from borrow pits Assumed that no forestry to be felled as part of the carbon calculation based on presence of commercial crop. Refer to ES Technical Appendix 2.5: Forestry Based on SEPA information on other wind farm sites, "In degraded bog, it should be anticipated that water table will be slightly lower than in intact blanket bog, [...]. Expected values for degraded bog would be expected =.3 m, minimum =.1 m, maximum =.5 m." Based on SEPA "In degraded bog, it should be anticipated that water table will be slightly lower than in intact blanket bog, [...]. Expected values for degraded bog would be expected =.3 m, minimum =.1 m, maximum =.5 m." Value based on professional judgement - see row 31 Not applicable but also reference to Natural England (213) Restoration of Degraded Blanket Bog (NEER 3) Area of borrow pits to be restored (ha) ES Technical Appendix 2.4: Borrow Pit Assessment Report Depth of water table in borrow pit before restoration with respect to the restored surface (m) Will you attempt to block all artificial ditches and facilitate rewetting? Will the habitat of the site be restored on decommissioning? Will the habitat of the site be restored on decommissioning? Will you control grazing on degraded areas? Will you manage areas to favour reintroduction of species Choice of methodology for calculating emission factors Results And Conclusions Site Specific (required for Planning Applications) The results of the carbon calculator show that the proposed will generate CO2 emissions, predominantly through the construction phase, where carbon rich soils are excavated to construct foundations, access tracks and other infrastructure. There is also potential for release of carbon through changes in hydrology. However, it is considered that the carbon losses as a result of the construction of the wind farm will be offset within approximately 2.4 years of operation when based on grid mix of electricity generation The results of the carbon assessment are shown in Table 2.8.2, with the full payback section included in Appendix 1. The full carbon calculator is available on request. Table 2.8.2: Results of Carbon Assessment Expected Minimum Maximum Depth of water table in borrow pit after restoration with respect to the restored surface (m) Time required for hydrology and habitat of borrow pit to return to its previous state on restoration (years) Period of time when effectiveness of the restoration of peat removed from borrow pits can be guaranteed (years) Early removal of drainage from foundations and hardstanding Water table depth around foundations and hardstanding before restoration (m) See details provided for Row 82. Net emissions of CO2 (t CO2 eq) Carbon payback time Coal fired electricity generation (years) Grid mix of electricity generation (years) Fossil fuel mix of electricity generation (years) Ratio of soil carbon loss to gain by restoration No Gains No Gains No Gains Ratio of CO2 eq. emissions to power generation (g/kwh) The proportion of greenhouse gas emissions from different sources is shown in Figure below: Water table depth around foundations and hardstanding after restoration (m) See details provided at Row 83. Time to completion of backfilling, removal of any surface drains, and full restoration of the hydrology (years) Value based on professional judgement/ original construction programme (22 months) Restoration of site after decommissioning Will the hydrology of the site be restored on decommissioning? Will you attempt to block any gullies that have formed due to the windfarm? Responses based on Ramboll Environ's professional judgement TA 2.8: Carbon Balance Assessment Ramboll Environ

28 Limited Figure 2.8.1: Proportions of Greenhouse Gas Emissions from Different Sources (Extracted from Carbon Calculator) The achieved carbon balance and payback time for the proposed is relatively short (2.4 years) when compared to the operational life of the project (25 years) and will contribute to the Scottish Government s commitments to a low carbon Scotland. Ramboll Environ TA 2.8: Carbon Balance Assessment