Rooley Moor Wind Farm Environmental Statement

Rooley Moor Wind Farm Chapter 7: Hydrology, Hydrogeology and Geology

CPL PAGE i

Rooley Moor Wind Farm Environmental Statement

7. Hydrology, Hydrogeology and Geology ...... 7-3 7.1 Introduction ...... 7-3 7.2 Objectives ...... 7-3 7.3 Statutory, Planning Policy, Legislation and General Guidance ...... 7-3 7.3.1 Statutory Planning Policy and Legislation ...... 7-3 7.3.2 General Guidance ...... 7-4 7.4 Consultation and Scoping ...... 7-4 7.5 Methodology ...... 7-7 7.5.1 Baseline Determination ...... 7-8 7.6 Baseline Conditions ...... 7-13 7.6.1 Study Area ...... 7-13 7.6.2 Climate and Topography ...... 7-13 7.6.3 Statutory Designated Sites ...... 7-13 7.6.4 Hydrology ...... 7-14 7.6.5 Flood Risk ...... 7-16 7.6.6 Geology and Peat ...... 7-18 7.6.7 Groundwater ...... 7-20 7.6.8 Groundwater Dependent Terrestrial Ecosystems ...... 7-21 7.6.9 Public Water Supplies and United Utilities Assets ...... 7-23 7.6.10 Private Water Supplies (PWS) ...... 7-24 7.7 Baseline Sensitivity ...... 7-25 7.7.1 Overall Surface Water Sensitivity ...... 7-25 7.7.2 Overall Groundwater Sensitivity ...... 7-25 7.7.3 Overall Geology Sensitivity ...... 7-25 7.8 Design Evolution ...... 7-26 7.9 Standard Practice Measures ...... 7-26 7.9.1 Development of a Detailed Construction Method Statement (CMS) ...... 7-26 7.9.2 Development of a Construction Environmental Management Plan (CEMP) ...... 7-26 7.9.3 Drainage Management Plan (DMP) ...... 7-27 7.9.4 Water Quality Monitoring ...... 7-27 7.9.5 Provision of an Environmental Clerk of Works (ECoW) ...... 7-28 7.10 Predicted Impacts ...... 7-28 7.10.1 Construction ...... 7-28 7.10.2 Operation ...... 7-33 7.10.3 Decommissioning ...... 7-35 7.11 Summary of Potential Impacts and Mitigation Measures ...... 7-35

CPL PAGE i

Rooley Moor Wind Farm Environmental Statement

7.12 Mitigation Measures ...... 7-41 7.12.1 Access Tracks ...... 7-41 7.12.2 Watercourse Crossings ...... 7-42 7.12.3 Wind Turbine Foundations and Hardstandings ...... 7-42 7.12.4 Substation Compound and Temporary Construction Compound ...... 7-43 7.12.5 Electric Cabling ...... 7-43 7.12.6 Borrow Pits ...... 7-44 7.13 Residual Effects ...... 7-45 7.13.1 Construction ...... 7-45 7.13.2 Operation ...... 7-46 7.13.3 Decommissioning ...... 7-46 7.14 Cumulative Impacts ...... 7-46 7.15 Summary and Conclusions ...... 7-48

Appendix 7.1: Private Water Supply Assessment Appendix 7.2: Outline Peat Management Plan Appendix 7.3: Peat Slide Risk Assessment Appendix 7.4: Mining Risk Assessment

CPL PAGE ii

Rooley Moor Wind Farm Environmental Statement

7. Hydrology, Hydrogeology and Geology

7.1 Introduction

7.1. This chapter assesses potential impacts to identified hydrological, hydrogeological and geological and receptors during the construction, operation and decommissioning of the development and outlines mitigation measures required to reduce any identified potential impacts of the development. 7.2. Information provided within this chapter is based upon the results of a desk based study utilising published resources, consultation with relevant stakeholders and statutory bodies, several site visits and collected field data. 7.3. The chapter is primarily concerned with the Development Area (as described in Chapter 4: Development Description, and shown in Figure 4.1 and land which is hydraulically connected to the Development Area.

7.2 Objectives

7.4. Rooley Moor Wind Farm, and outlines mitigation measures required to control the predicted effects of the Development. Potential effects to hydrology, hydrogeology and geology include:  Changes to drainage patterns;  Changes to flood risk;  Changes to the quality and/or quantity of surface water and groundwater;  Pollution of public water sources and/or private water supplies (PWS); and  Other changes to downstream watercourses including changes in erosion and deposition patterns.

7.3 Statutory, Planning Policy, Legislation and General Guidance

7.5. This assessment has been undertaken with regard to statutory and general guidance, and a range of environmental legislation including the following:

7.3.1 Statutory Planning Policy and Legislation  EU Water Framework Directive (2000/60/EC);  Environmental Protection Act 1990;  Water Resource Act 1991;  Groundwater (England and Wales) Regulations 2009;  UK Water Quality (Water Supply) Regulations 2000 (amendment) Regulations 2007;  Freshwater Fish Directive (2006/44/EC);  Environment Act 1995;  Land Drainage Act 1991;  Environmental Damage (Prevention and Remediation) Regulations 2009;  Town and Country Planning Act 2012;

CPL PAGE 7-3

Rooley Moor Wind Farm Environmental Statement

 Private Water Supply Regulations 2009;  Control of Pollution Act 1974; and  Contaminated Land (England) Regulations 2006.

7.3.2 General Guidance  National Planning Policy Framework, Department for Communities and Local Government (2012);  Environment Agency, Underground, Under Threat, Groundwater protection: policy and practice (GP3) (2006);  Environment Agency, Piling and Penetrative Ground Improvement Methods on Land Affected by Contamination: Guidance on Pollution Prevention (2001)  EA Pollution Prevention Guidance (PPG) Notes: o PPG 1 General guide to the prevention of water pollution (2001); o PPG 2 Above ground oil storage tanks (2004); o PPG 3 Use and design of oil separators in surface water drainage systems (2006); o PPG 5 Works in, near or liable to affect watercourses (2007); o PPG 6 Working at construction and demolition sites (2003); o PPG 21 Pollution incident response planning; o PPG22 Incident Response – Dealing with Spills; and o PPG23 Maintenance of Structures over Water.  CIRIA Report C532 Control of water pollution from construction sites (2001);  CIRIA Report C692 Environmental good practice on site (third edition) (2010); and  Construction Code of Practice for the Sustainable Use of Soils on Construction Sites (2009).

7.4 Consultation and Scoping

7.6. A summary of scoping and consultation responses in relation to this chapter is detailed in Table 7.1. Copies of scoping responses received from the consultees can be found in Appendix 2.1.

Table 7.1 Scoping Responses

Authority Response Proposed Action Environment Flood Risk Assessment (FRA) should be FRA required – currently not included in Agency (EA) included. scope of works. United Initial consultation highlighted concerns Majority of infrastructure to be located off Utilities around water quality both from construction peat greater than 0.5m depth. and long term running of the wind farm, Coronation Power are working with UU and mainly related to colour and suspended have agreed that a joint approach to water solids. quality monitoring could support both the Water quality monitoring will be essential in development of the wind farm site and establishing a robust baseline for the assessment of ongoing peatland restoration catchments around the wind farm. Peat work being undertaken by UU. The

CPL PAGE 7-4

Rooley Moor Wind Farm Environmental Statement

Authority Response Proposed Action discolouration of water supply is a key issue collaborative approach will look to share for UU and presents an expensive on-going data and rationalise monitoring and problem to resolve. Any monitoring will need sampling locations / regimes. to include for colour. The Coal Past coal mining activities and the presence Mining risk assessment has been Authority of surface coal resources should be completed and is included as Appendix considered. This should take the form of a 7.4. risk assessment, together with mitigation measures. The location and stability of abandoned mine entries should be considered and the extent and stability of shallow mine workings, outcropping coal seams, unrecorded mine workings, minewater, hydrogeology and mine gas should be considered. Consider whether Coal Authority permission is required to intersect, enter or disturb and coal or coal workings during site investigation or development work If surface coal resources are present, consider whether prior extraction of the mineral resource is practicable and viable Lancashire The site is on Mineral Safeguarding Area A Mining Risk Assessment has been County and survey work would need to prove peat completed and is included as Appendix Council had been worked out and exhausted and 7.4. that any proposed development would not A Peat Management Plan (PMP), included damage the peat land resource. as Appendix 7.2 demonstrates that the proposed development will not result in any removal of peat from the site and highlights restoration proposals for excavated peat.

Natural  Impacts of development on hydrology Design of the wind farm layout has avoided England together with environmental and erosion peat over 0.5m in depth where possible as protection demonstrated by evidence presented in the Peat Slide Risk Assessment (PSRA)  Application falls within a priority habitat, included as Appendix 7.3. The EIA blanket peat assessment contained within this chapter  Requirements for EIA for wind farms on includes assessment of risk to peatland peat greater than 0.5m provided in resources with respect to potential changes “Investigating the impacts of wind farm in hydrogeological regimes, while Chapter development on peatlands in England: 8: Ecology assesses risk to peatland Part 1 Final Report” habitat and Chapter 15: Other Issues  Scope for mitigation of adverse impacts assesses any loss of peat as a function of and opportunities for improved peatland the overall carbon balance assessment for management to be addressed the site.

CPL PAGE 7-5

Rooley Moor Wind Farm Environmental Statement

Authority Response Proposed Action  Compensation for adverse effects may Opportunities will be sought in conjunction be possible through peat restoration with UU for restoring peatland habitat as measures in the form of habitat detailed in Section 8.10.2 of Chapter 8: management plans Ecology.  Functional components of the peat Geological and hydrologically dependant system as a whole which includes areas SSSIs have been identified within the of non-active bog as well as active bog baseline and assessment reporting of this should be considered. Chapter.  Impacts on local geological sites should be considered Greater  Comprehensive peat depth and quality Surveys of peat depth and quality of peat Manchester surveys required to inform layout of have been undertaken to inform PSRA Ecology Unit turbines and access tracks and mitigate reporting and are presented in Appendix for damage to peat 7.3.  Mapping of bare peat, bare mineral Best practice and mitigation measures ground and areas partially vegetated outlined in Section 7.12 will ensure residual from aerial photographs risk to peat is not significant.  Develop a water accumulation indicator map and wetness index using LiDAR data  Ground truthing mapping and field assessment to identify likely causes of degradation and most appropriate methods of remediating or restoring  Full details of measures to be taken to mitigate any possible damage to peat  Hydrological studies should consider potentially damaging impacts of drying parts through increased drainage  Particular issues include: o Constructing tracks on peat and mineral soils o Construction of turbine and crane foundations on peat and mineral soils o Dealing with surplus peat o Dealing with surplus mineral material/soils o Installing trenches for HV cables o Stream/drain crossing to avoid scour and erosion Rochdale Council Should be cross referenced with ecology The EIA assessment contained within this chapter in relation to peatland condition chapter includes assessment of risk to peatland resources with respect to potential  Impact on water quality from peat changes in hydrogeological regimes, while

CPL PAGE 7-6

Rooley Moor Wind Farm Environmental Statement

Authority Response Proposed Action oxidisation and increased turbidity should Chapter 8: Ecology assesses risk to be assessed peatland habitat and Chapter 15: Other  Definition of deep peat being of a depth Issues assesses any loss of peat as a of 2m or greater is flawed. function of the overall carbon balance assessment for the site.  Reference should be made to “Investigating the impacts of windfarm Mining risk assessment has been development on peatlands in England: completed and is included as Appendix Part 1 Final Report” 7.4.  Account to be taken of existing development at Scout Moor and lessons learned from disturbance of substrate.  Flood Risk Assessment will be necessary  Coal Authority should be consulted for mining records. BGS can also provide relevant detailed information.  Baseline assessment should cross reference Minerals and Waste DPD’s covering the PDA, in particular Minerals Safeguarding Areas.

7.5 Methodology

7.7. This section outlines the methodology adopted to assess the effects impacts of the proposed Development upon the local hydrological, hydrogeological, geological and peat environments. 7.8. The scope of the assessment is to identify:  Constraints on activities due to hydrology, hydrogeology, geology and peat;  Potential effects and risks associated with construction, operation and decommissioning activities that can be controlled through best practice; and  The significance of residual effects. 7.9. Information provided within this chapter is based upon the results of a desk based study utilising published resources, consultation with relevant stakeholders and statutory bodies and several site visits during 2013 and 2014.

Table 7.2 Baseline Data Sources

Topic Source of data and information Climate and Ordnance Survey mapping - Landranger Series (1:50,000) topography Flood Estimation Handbook (FEH) Surface water quality Rochdale Council and Rossendale Council and quantity Environment Agency (EA) United Utilities (UU) Public water supplies, Rochdale Council and Rossendale Council

CPL PAGE 7-7

Rooley Moor Wind Farm Environmental Statement

Topic Source of data and information Private water supplies Property owners (information regarding private water supplies) (PWS) Fisheries Environment Agency (EA) Groundwater Environment Agency (EA) properties Abesser, C, Shand, P. & Ingram, J, 2005. Baseline Report Series 18. The Millstone Grit of Northern England. British Geological Survey Commissioned Report No. CR/05/015N. BGS UK Hydrogeology Viewer Available online at http://mapapps.bgs.ac.uk/hydrogeologymap/hydromap.html Last accessed 20th March 2014. Solid and drift geology BGS GeoIndex Onshore online mapping  Bedrock geology (scale 1:50,000)  Superficial deposits (scale 1:50,000)  Faults and other linear features (scale 1:50,000) Abstractions and Environment Agency (EA) discharges Rochdale Council and Rossendale Council

7.5.1 Baseline Determination 7.10. The methodology is based upon the collection of information from a wide variety of data sources including published material and consultation with statutory bodies. Table 7.2 details the data sources referred to throughout this assessment. 7.11. There are no relevant published guidelines or criteria for assessing and evaluating impacts on hydrology, hydrogeology or geomorphology within the context of an EIA. This assessment is based on a methodology derived from the Institute of Environmental Management and Assessment (IEMA) guidance (2004) (Ref. 7-1). The methodology sets out a list of criteria for evaluating the environmental impacts, as follows:  The type of impact (i.e. whether it is positive, negative, neutral or uncertain);  The policy importance of the resource under consideration on a scale of sensitivity (i.e. high, medium or low) as defined within Table 7.3.  The magnitude of the impact in relation to the resource that has been evaluated, quantified using the scale high, medium, low, or negligible defined within Table 7.4; and  The probability of the impact occurring based on the scale of certain, likely, unlikely, or rarely (Table 7.6 ).

Table 7.3 Definitions of Policy Importance and Sensitivity

Sensitivity Hydrological / hydrogeological / geological definition High  High environmental importance; international or national value including Ramsar sites; Special Areas of Conservation (SAC); Special Protection Areas (SPAs); and Sites of Special Scientific Interest (SSSIs);  WFD high/good ‘ecological status’

CPL PAGE 7-8

Rooley Moor Wind Farm Environmental Statement

Sensitivity Hydrological / hydrogeological / geological definition  Public water supplies and principal or highly productive aquifers with high aquifer vulnerability.  Nationally important fisheries containing protected species such as Freshwater Pearl Mussel.  Areas with a high risk of flooding. Medium  WFD high/good ‘ecological and chemical status.’  Private water supplies.  Groundwater that supports highly dependent groundwater dependent terrestrial ecosystems (GWDTE).  Areas with a moderate risk of flooding, with existing flooding being confined to areas immediately adjacent to watercourses.  Highly productive aquifer with low to medium vulnerability or moderately productive aquifers with high vulnerability.  Regionally important fisheries.  Pristine or active peat bog habitat; evidence that peat body has an intact hydrological system/possibility that peat could recover to pristine status. Low  Low environmental importance (e.g. WFD poor/bad ‘ecological status’).  Low productivity/non aquifer.  Private water supplies located within the vicinity of a mains water supply or private water supplies used for agricultural purposes and not for drinking water purposes.  Degraded fisheries or receptor not important for fisheries.  Low risk of flooding.  Groundwater that supports moderately dependent GWDTE.  Degraded or inactive peat; small isolated areas of peat; soil not sensitive to change, e.g. degraded/grazed; shallow, evidence of widespread erosion. Significant active land drainage has occurred resulting in ongoing dewatering of peat.

Table 7.4 Impact Magnitude Criteria Receptor Magnitude High Medium Low Negligible Runoff regime Long term Temporary change Short term change No measureable irreversible change in overall volume of in volume of runoff change in site in overall volume of runoff from the and changes to runoff regime runoff from the whole site and flow paths and whole site and changes to flow rates in localised changes to flow paths and rates areas of the site paths and rates resulting in change resulting in change resulting in change in flood risk and in flood risk and in flood risk and erosion potential. erosion potential to erosion potential. localised areas only. Surface water Measureable Measureable Measureable No measureable change in water change in water change in water change in surface

CPL PAGE 7-9

Rooley Moor Wind Farm Environmental Statement

Receptor Magnitude High Medium Low Negligible quality quality status with quality status with quality but no water quality. respect to EQS for respect to EQS for change with more than one less than one respect to EQS. No month; long term month; temporary significant impact irreversible impact impact on aquatic on aquatic on aquatic ecosystems in the ecosystems. ecosystems. medium term. Water Supply Measurable Measurable Measurable No measureable change in the change in the change in the change in water quality or volume of quality or volume of quality or volume of supply. the available the supply for more the supply for less supply for than 1% of than 1%, but no abstraction with samples with change with respect to The respect to The respect to The Water Supply Water Supply Water Supply Regulations; Regulations; Regulations. No leading to change temporary visual change in pressure in water pressure colouration change or flow. and/or in supply and alteration to volumes. sediment content. Riverine flow Measurable Measurable Detectable change No measureable regime change in riverine change in riverine in riverine flows but change in riverine flows resulting in a flows resulting in a no measurable flow regime. change in dilution change in dilution change in dilution capacity or change capacity or change capacity or flood in flood risk for in flood risk for risk. watercourses or smaller water bodies watercourses or directly monitored water bodies, not under the WFD. directly monitored under the WFD. Geomorphology Permanent change Permanent change Temporary change No change in to geomorphology in geomorphology in geomorphology geomorphology. over a large scale over a limited area over a limited area including large including some including slight changes in erosion changes in erosion changes in bed and deposition and deposition morphology, regimes. regimes. sedimentation patterns and erosion rates. Groundwater Irreversible or Measurable Short term No measurable flow regime permanent change change to the reversible changes change in the to the recharge, recharge, flow or to the recharge, recharge, flow or flow or discharge of discharge of flow or discharge of discharge of groundwater. May groundwater. May groundwater. groundwater. impact upon impact upon Impacts are limited

CPL PAGE 7-10

Rooley Moor Wind Farm Environmental Statement

Receptor Magnitude High Medium Low Negligible licenced licenced to small discrete groundwater groundwater areas. abstraction, water abstraction, water supply to supply to ecosystem or ecosystem or groundwater base groundwater base flow to a flow to a watercourse such watercourse but that it impacts on with no impact on WFD criteria or WFD standards. standards. Impacts affect large or multiple area(s). Groundwater Permanent or long Temporary change Measurable but No measureable Quality term (>one month) in groundwater temporary change change in change in quality, changing in groundwater groundwater groundwater site quality with quality, but not quality. quality with respect respect to EQS for changing status to EQS for more less than one with respect to than one month. month. EQS. Peat hydrology Significant Moderate alteration Minor alterations to No measureable / Quality / permanent to peat hydrology peat hydrology. change in peat volume and alteration to peat resulting in hydrology. extent of peat hydrology resulting localised changes in the change of in the status of status of the peat peat bodies. Any body. changes are largely temporary.

7.12. Professional judgement is used to assess the findings in relation to each of these criteria to give an assessment of significance for each impact. This utilises the sensitivity of identified receptors (using the criteria in Table 7.3) and the magnitude of potential impacts (using the criteria in Table 7.4). Potential impacts are then evaluated as to whether they are considered to be of high, moderate, low, or no significance. As a guide, a table has been developed whereby the combination of sensitivity and magnitude give the significance of the potential impact (Table 7.5).

Table 7.5 Evaluation of Potential Impact

Receptor Magnitude of Impact Sensitivity Negligible Low Medium High High Not Significant Moderate Major Major Medium Not Significant Minor Moderate Major Low Not Significant Not Significant Minor Moderate

CPL PAGE 7-11

Rooley Moor Wind Farm Environmental Statement

7.13. The likelihood of potential impacts occurring is then assessed. To classify the probability of occurrence for a potential impact it is necessary to understand how regularly a given event or outcome will come to pass. This can be assessed in a number of ways including assessments based on historical data, quantitative analysis, or experience from other similar sites. The likelihood of occurrence (Table 7.6 ) of potential impacts is then assessed against the criteria in ranging from a scale of rarely to certain.

Table 7.6 Definitions of Likelihood of Occurrence

Likelihood of occurrence Definition Any consequence that is likely in the medium term and inevitable throughout Certain the assessment timescale. i.e. the consequence will happen if the development goes ahead. There is a high probability that the consequence will be realized within the Likely lifetime of the development or duration of the activity. It is possible but unlikely that any consequence would arise during the Possible lifetime of the development. There is a very low probability that any consequence will ever arise within the Rarely lifetime of the development or duration of the activity.

7.14. The likelihood of significant impacts occurring is then combined with the evaluation of potential impacts to assess likely significant impacts using the matrix in Table 7.7. 7.15. Typically, significant impacts assessed as minor, or less are considered not significant in terms of EIA. Impacts evaluated as having a moderate or high significance are defined as significant for the purpose of the EIA. If the assessment results in moderate or high significant impact, then additional mitigation measures will need to be considered.

Table 7.7 Likely Significant Impact Matrix

Evaluation of Likelihood of Occurrence Potential Impact Rarely Unlikely Likely Certain Major Minor Moderate Major Major Moderate Negligible Minor Moderate Moderate Minor Negligible Negligible Minor Minor Not Significant Negligible Negligible Negligible Negligible

7.16. The impacts recorded in highlighted cells are ‘significant’ in terms of the EIA Regulations (The Town and Country Planning (Environmental Impact Assessment) Regulations 2011). 7.17. Mitigation measures to reduce the impact of any identified potential impacts identified to occur during the construction, operation and decommissioning of the wind farm are then applied. The likelihood of any residual significant impacts occurring after mitigation measures have been implemented is then assessed using Table 7.6. 7.18. Table 7.7 is then used again to assess the residual likely significant impact.

CPL PAGE 7-12

Rooley Moor Wind Farm Environmental Statement

7.6 Baseline Conditions

7.6.1 Study Area 7.19. The Development Area mostly comprises open moorland across a high plateau. This study considers impacts to hydrological, hydrogeological and geological receptors (including peat) within the Development Area. Impacts to these receptors outside of the site boundary are considered for up to 2km, or further where a hydrological connection deems it necessary.

7.6.2 Climate and Topography 7.20. The average annual catchment rainfall for the area is approximately 1,510mm based on data obtained from the FEH1, indicating a moderately wet climate having the potential to exhibit a moderately high runoff regime. 7.21. The study area encompasses the eastern extent of an upland plateau which forms Rooley Moor, Knowl Moor and Scout Moor. Much of the study area is elevated above 350 metres above ordnance datum (m aOD) and encompasses three main peaks which form a north-south trending ridge along the length of the Development Area. These peaks are;  Top of Leach located in the north of the study area, summit elevation 474m aOD;  Hammer Hill located in the centre of the study area, summit elevation 440m aOD; and  Top of Pike located in the south of the site, summit elevation 398m aOD. 7.22. These hills form the crest of a watershed which creates six surface water catchments; these are described further below.

7.6.3 Statutory Designated Sites 7.23. There are no designated sites within the Development Area. 7.24. There is only one designated site within 1km of the Development Area, the Lee Quarry Site of Special Scientific Interest (SSSI). 7.25. Lee Quarry is a large disused quarry on the south side of the Rossendale Valley, south of Bacup. The quarry is a designated Geological SSSI because it is rich in trace-fossil assemblages and good sedimentary features, making it of great importance to studies of late Carboniferous environments and palaeogeography. Lee Quarry is now an important tourist attraction since being converted into a purpose built mountain biking centre by Rossendale Borough Council. As the designation has no hydrogeological or hydrological component and the quarry is located outside the Development area so will not be impacted by wind farm activities. This feature is not considered further within this assessment. 7.26. There is only one designated site within 2km of the Development Area; a Local Nature Reserve Site, Healy Dell which is located approximately 1km from the Development Area in Spodden Valley on the Rochdale-Whitworth border. The nature reserve has been designated for its natural beauty and archaeological feature. No hydrological, hydrogeological or geological features have been identified as relating to this designation and this feature is not considered further within this assessment.

1 FEH (Flood Estimation Handbook) CD-ROM 3 produced by the CEH (Centre for Ecology and Hydrology, 2009)

CPL PAGE 7-13

Rooley Moor Wind Farm Environmental Statement

7.6.4 Hydrology Surface Water Catchments

7.27. The study area drains five surface water catchments. These catchments ultimately drain to the River Irwell (north and west), the River Spodden (east) or Nadden Brook (south) (see Figure 7.1). Several of the catchments contain United Utilities public water supply reservoirs which receive surface water inputs from many of the watercourses located within the upper parts of the catchments. Outflow from the reservoirs into the lower catchments is controlled by a series of sluice gates, these are further described in Section 7.6.9. Catchments draining to River Irwell

7.28. Cowpe Moss catchment is located towards the far north-west of the study area and contains the Cowpe Moss reservoir, a raw water reservoir operated by United Utilities. The reservoir has been constructed in the base of a very steep valley and is primarily fed by three, un-named surface water sources which rise on the steep cliff above the reservoir. Ordnance survey mapping marks the presence of numerous springs and wells above the reservoir, suggesting that groundwater may also contribute water to the reservoir. Cowpe Reservoir also likely receives some runoff from the up gradient Cowpe Moss area. The reservoir is stocked with trout and is a popular destination for local angling groups and ultimately drains to the River Irwell located to the north. There are no surface water courses which rise within Development Area and flow into Cowpe Moss catchment; the Development Area runs along the watershed boundary of the catchment which means there is no direct hydraulic connection between the site and Cowpe Moss catchment. 7.29. Greens Moor catchment drains the north of the site and is the only catchment which does not contain a reservoir. The main surface watercourse is Well Clough and associated tributaries which rises within the Development Area and flows north and discharges directly into the River Irwell c.1km north of the Development Area. Lower in the catchment, typically below an elevation of 360m aOD, numerous springs are mapped as emerging from the steep hillside which in turn feed a network of small streams that ultimately discharge into the River Irwell. The nearest spring is over 250m down gradient of the northern tip of the site boundary. Several disused quarries are located on the mid slopes of Greens Moor catchment, including the Lee Quarries and associated SSSI. Catchments draining to River Spodden

7.30. Cowm catchment is located in the north-east of the study area, a small (0.38km2) lobe of the Development Area extends into the catchment. The Cowm catchment contains the Cowm Reservoir; the reservoir is a United Utilities asset and is currently used as a recreational space. It is not used for water supply. The Cowm catchment is drained by several surface water courses, namely:  Walstead Clough which rises near Old Slink Stack near the top of the catchment within the application boundary and flows directly into Cowm Reservoir;  Cowm Brook (and nearby, un-named watercourses) rise mid-way down the Cowm catchment, over 185m down gradient of the site boundary and flow towards the former quarrying area, Britannia quarries. The Britannia quarries contain several, artificial water bodies within the flooded quarry working areas. 7.31. As for the Cowpe Moss catchment, OS mapping indicates the presence of numerous groundwater springs emerging on the steep mid-slopes of the catchment.

CPL PAGE 7-14

Rooley Moor Wind Farm Environmental Statement

7.32. Spring Mill and Prickshaw catchment is located on the eastern side of the Development Area. The catchment contains the Spring Mill Reservoir and the Prickshaw Reservoir, both United Utilities assets operated as a public water supply. All surface water courses in the upper part of the catchment drain into the reservoirs. 7.33. Spring Mill reservoir receives flow from:  the Prickshaw Brook which rises towards the top of the catchment, outwith the Development Area; and  The Fern Isle Brooks, which is a major tributary of the Prickshaw Brook and the confluence is located approximately 300m up gradient of the reservoir. The headwaters of the Fern Isle Brook rise within the Development Area near the disused Bagden Quarry. 7.34. The Prickshaw Reservoir comprises three small water bodies which are fed by one main, un-named surface water course which rises within the Development Area near Prickshaw Slack. Catchments draining to Naden Brook

7.35. Naden and Greenbooth Reservoir catchment is the largest of the study area catchments at 10km2 and drains into a series of reservoirs before discharging into the Naden Brook 1km to the south of the Development Area. Much of the western half of this catchment is located within the Development Area. 7.36. Little Ding and Ding Clough surface watercourses rise within the Development Area, just below the disused Ding Quarry. Both streams flow due south and discharge into the Naden Higher Reservoir. 7.37. An un-named stream with five tributaries flows into the Naden Higher Reservoir on its eastern bank. The headwaters of the stream rise within the Development Area; 7.38. An un-named stream flows into the Naden Middle Reservoir on its eastern bank. The headwaters of the stream rise within the Development Area;  A small spring watercourses rises at Forsyth Brow, close to the Development Area and flows east and discharges into the Greenbooth Reservoir;  A further two small spring fed watercourses rise at Forsyth Brow and flow south, ultimately discharging into the Naden Brook 1km to the south of the Development Area. Surface Water Quality

7.39. As part of the requirements for the Water Framework Directive (WFD), the EA has described the general quality of watercourses within each river basin district and the pressures the water environment faces. The study area falls within Irwell Catchment in the North West river basin district. The surface watercourses identified within the Development Area have not been assessed by the EA as they are too small, however, the three main receiving watercourses, the River Irwell, River Spodden and Nadden Brook have been assessed and a summary of their current and future predicted status (using criteria defined under the WFD) is presented in Table 7.7.

Table 7.7 Summary of Surface Water Quality2

WFD Parameter River Irwell River Spodden Naden Brook

Hydromorphological Status Heavily modified Heavily modified Heavily modified

2 Data from Environment Agency, available online at http://maps.environment-agency.gov.uk/wiyby/wiyby Last Accessed 20th March 2014.

CPL PAGE 7-15

Rooley Moor Wind Farm Environmental Statement

WFD Parameter River Irwell River Spodden Naden Brook

Current Ecological quality Moderate Potential Moderate Potential Moderate Potential

Current Chemical Quality Good *DRA *DRA

2015 predicted ecological quality Moderate Potential Moderate Potential Moderate Potential

2015 predicted chemical quality Good *DRA *DRA

Overall Risk At risk At Risk At Risk Biological Quality

Overall biological quality Poor *NA Moderate

Diatoms *NA Good *NA

Fish Poor Good Good

Macro-invertebrates Moderate Moderate General Physico Chemical Quality

Ammonia High High High

Dissolved Oxygen High High High

pH High High High

Phosphate Good High High Specific Pollutants Quality

Ammonia High High High

Copper High High High

Iron High High High

Zinc High High High

* DRA = Does Not Require Assessment * NA = Not Assessed

7.40. In summary, chemical water quality for all three receiving watercourses is high despite only the River Irwell requiring assessment for chemical quality.

7.6.5 Flood Risk Fluvial Flood Risk

7.41. Indicative flood mapping published by the EA3 shows the Development Area is located entirely outside the mapped floodplain, indicating that this risk is negligible.

3 Data from Environment Agency, available online at http://maps.environment-agency.gov.uk/wiyby/wiyby Last Accessed 20th March 2014.

CPL PAGE 7-16

Rooley Moor Wind Farm Environmental Statement

Surface Water Flood Risk

7.42. Indicative surface water flood risk mapping published by the EA3 suggests the risk of flooding is generally very low. Areas of medium and high surface water flood risk do occur within the Development Area and wider study area; these areas are concentrated along existing surface water flow paths and topographic lows such as gullies or former quarry areas. 7.43. During rainfall events, flows pass overland following topographic grades to gullies in peat, watercourse channels or tributaries down-slope and eventually into the receiving catchment watercourses as defined in the surface water section above. It is likely that once flows are in these channels, they will travel relatively quickly off the steep hillsides. Potential exists for localised surface ponding of water during or following these conditions; however, flooding is likely to be shallow and only inundate some isolated low lying areas, for instance in the areas directly adjacent to watercourses. Artificial Drainage Systems 7.44. The existing Rooley Moor Road public bridleway and other minor public paths cross several minor watercourses within the Development Area. Culverts are generally used to convey flow under the tracks, the majority of which were observed to be in good condition and free of debris. Plate 1 and Plate 2 below detail an example of an existing crossing on Rooley Moor Road on a tributary of Higher Naden Reservoir, at NGR 385745 418172. Plate 2 View downstream from existing crossing Plate 1 Rooley Moor Road existing crossing

7.45. Topography and indicative flood risk mapping provided by the EA shows the Development Area to be generally at low risk of inundation mainly limited to a risk during high rainfall conditions causing overland flow and minor isolated ponding in some areas, particularly around areas which are saturated under normal conditions, i.e. stream margins and boggy areas. Tidal Flood Risk

7.46. The Development Area is over 350m above sea level at its lowest point; therefore this risk does not apply.

CPL PAGE 7-17

Rooley Moor Wind Farm Environmental Statement

Groundwater Flood Risk

7.47. Groundwater flooding is not considered to be a risk to the development. This is due to the steep topography of the site and the relative depth to the regional water table (springs mapped from 360m aOD), over 50m below the minimum site elevation.

7.6.6 Geology and Peat Superficial Geology

7.48. British Geological Survey (BGS) 1:50,000 scale superficial mapping shows superficial deposits are largely absent from much of the Development Area and there are large areas where the bedrock outcrops at the surface. However, areas of superficial deposits have been mapped; Glacial Till comprising stiff grey brown sandy silty clay with occasional gravel and cobbles is shown across the very southern part of the Development Area and locally around Prickshaw in the south and east. A small, isolated area of Head deposits is shown around the Rooley Moor Brow area comprising glacially derived materials. Bedrock and Structural Geology

7.49. The bedrock on site and in the wider study area comprises rocks from the Upper Carboniferous period (Figure 7.2). The outcrop in the northern and central part of the Development Area comprises the Namurian Millstone Grit (NMG) series which are overlain by the Westphalian Pennine Lower Coal Measures (PLCM) in the southern part of the Development Area. Towards the north, the NMG is faulted against the PLCM in a series of normal faults. 7.50. The NMG comprises a thick succession of interbedded sandstones, siltstones, mudstones and subordinate thin coals and seat earths. The PLCM comprises alternating sandstone and shale strata and several significant coal seams which were extensively mined in the past. 7.51. The study area is located on the crest of a large south-west trending open fold of the Rossendale Anticline. The oldest rocks of the NMG are exposed in the core of the anticline in the centre of the site. The bedrock geology is faulted by many north-west to south trending normal faults. These faults have formed a series of graben and half graben blocks across the area. Peat

7.52. BGS 1:50,000 scale superficial geological mapping shows the presence of peat deposits in the northern, eastern and western areas of the site (see Figure 7.3). The southern half of the site is mapped as being peat free. Peat probing was carried out across the study area at 348 locations on a 100m grid, the detailed results of this exercise are recorded in Appendix 7.3. The occurrences of peat correspond well with published geological mapping. Recorded peat depths ranged from 0.0m to 2.1m, where peat was encountered the average depth was between 0.5m and 1.0m depth. Some 123 peat- free locations were identified, several of which were associated with spoil heaps or located in the southern regions of the site. Peat depths of 1.75m or greater were recorded at eight locations, predominantly located in the north of the site, north of Ding Quarry near the summit of Top of Lench hill. 7.53. NVC mapping identified that the majority of the peat land in the Development Area was vegetated by degraded/modified mire communities such as M20 and M25. Chapter 8: Ecology suggests that the peat would have formerly been dominated by blanket mire vegetation. Blanket mire develops in areas of high rainfall, and has an ombrogenous (that is, water-fed by rainfall) hydrological regime, however due to the influence of continuous heavy grazing (perhaps coupled with burning and atmospheric

CPL PAGE 7-18

Rooley Moor Wind Farm Environmental Statement

pollution) the original bog vegetation becomes modified to such to lower ecological value habitats. Much of the peat land across the Development Area, south of Ding quarry, around Ding Clegg and further east around Hamer Hill is therefore considered to be degraded. 7.54. The findings of the ecology study are supported by peat characteristic analysis; Von Post humidification scores for the acrotelm were generally H6-H7, indicating moderately to highly decomposed peat with a very indistinct plant structure. These scores are higher than would be expected for a healthy, actively peat-forming acrotelm (which should be less decomposed) suggesting that the acrotelm layer in the study area is degraded. The interpretation that the peaty acrotelm is degraded across much of the site is reflected in the moisture Von Post scores which were typically B2- B3, indicating a low to moderate moisture content in the peat. Dip-well levels from piezometers installed in the peat around turbine locations indicate that average water table depth across the site is 0.25m, below the acrotelm layer. The acrotelm needs to be saturated in order to support the bog plants which in turn form peat and help stabilise it. 7.55. Two larger areas of M3 bog pool communities were mapped to the north of Ding Quarry (12.36ha) and on Brandwood Moor (13.3ha). According to the JNCC (2010)4, M3 is typically found in areas of shallow peat in acidic environments and is commonly associated with eroded blanket mire in north-west f Britain. It is reported to represent a seral stage in the redevelopment of active mire vegetation disruption. Water levels in the peat in this area were at ground level, indicating total saturation through the peat profile. In addition, some small bog pools were observed. In conclusion, these areas of peat land represent active but not pristine areas bog with a relatively intact hydrological regime. 7.56. A comprehensive multi-factor approach was adopted to identify peatslide prone areas within the Rooley Moor site. A total of 348 positions on a 100m grid pattern were examined in detail and the results of the study were used to establish constraints to avoid areas identified as potentially vulnerable to ground movements. Peat slide risk across the majority of the Development Area was found to be low, however, some isolated areas of moderate risk were identified. No areas of high peat slide risk were identified. Quarrying and Mining

7.57. A separate Mining Risk Assessment Report5 (which is presented in Appendix 7.4) identified that the Development Area and wider study area has been subjected to extensive mining and quarry activity in the past. There are currently no active workings. The report found 33 recorded mine entries within the Development Area; of these, only 6 have been treated or capped. The report also found evidence for extensive coal mining of seams at numerous locations within the Development Area which have not been officially recorded. 7.58. OS mapping shows numerous small sandstone quarries within the site boundary with larger quarries located in the wider study area (such as Ding Quarry or Lee Quarry). Several of the smaller quarries have been completely backfilled to an unknown standard whilst the rest remain open or partially backfilled. The mining risk assessment found that the Development Area had an overall Medium to High risk of mining related subsidence with respect to the Development. As such, all known and suspected constraints relating to mining activity have been mapped and are shown in Figure 3.1. 7.59. Areas with historical mining activity have in some cases led to a decrease in groundwater quality; as shown in

4 National Vegetation Classification: field guide to mires and heaths. Joint Nature Conservation Committee (2010). Available online at http://jncc.defra.gov.uk/pdf/mires_heaths.pdf Last accessed 18/06/14. 5 Mining Risk Assessment Report: Rooley Moor Wind Farm. Prepared by SKM, March 2012.

CPL PAGE 7-19

Rooley Moor Wind Farm Environmental Statement

7.60. Plate 3, below. Groundwater springs contaminated with ferric iron deposits colloquially known as ‘ochre’ are observed emerging within the study area.

7.6.7 Groundwater Aquifers

7.61. The EA online mapping tool6 indicates that no Source Protection Zone’s (SPZ) are located within the Development Area or wider study area. 7.62. There are no superficial aquifers located within the Development Area, however, superficial aquifers are identified along the River Spodden, River Irwell and Nadden Brook watercourses, these likely comprise recent alluvial deposits. 7.63. EA mapping shows that the bedrock beneath the Development Area is a Secondary A aquifer. This classification refers to both the NMG series and the PLCM formation. A secondary A aquifer classification refers to permeable layers of rock capable of supporting water supplies at a local rather than strategic scale. In some cases these aquifers can form an important source of baseflow to rivers. 7.64. The NMG forms a multi-layered aquifer system in which persistent, thick sandstone horizons act as separate aquifers with intervening mudstones and shales acting as aquicludes and aquitards7. The sandstones are generally well cemented and groundwater storage and transport is restricted largely to joints and fractures. 7.65. A number of perched water tables occur in the multi-layered aquifer system meaning that the depth to groundwater within the aquifer at any location is difficult to define. Springs are reported to be common at the base of sandstone layers and at junctions between shale and sandstone horizons7. Numerous springs and wells are mapped on the hillsides below Rooley Moor (and the main development area) suggesting that this is an important spring line. 7.66. The PLCM formation is described8 as a moderately productive, multi-layered aquifer. As for the NMG, it is the sandstone layers which form aquifers and springs are common features. Groundwater Quality

7.67. The EA online mapping tool 9 indicates that groundwater within the NMG and PLCM has been assessed under the WFD as having ‘good’ quantitative status. The predicted quantitative status remains good for 2015. The qualitative status is assessed under the WFD as being ‘poor’, with this assessment remaining for 2015. Based on observations made during site visits, it is considered likely this status is related to the mine workings in the area and the impact on groundwater quality. 7.68. The water quality in areas which have been mined is often poor as oxidation of sulphurous mine water leads to the creation of conditions for Acid Mine Drainage (AMD) and the formation of characteristic ochre deposits. This was observed at a spring which emerges at Snipe Barn Farm to the east of the Rooley Moor Development Area (see Error! Reference source not found. below). However, in areas

6 Data from Environment Agency, available online at http://maps.environment-agency.gov.uk/wiyby/wiyby Last Accessed 20th March 2014 7 Abesser, C, Shand, P. & Ingram, J, 2005. Baseline Report Series 18. The Millstone Grit of Northern England. British Geological Survey Commissioned Report No. CR/05/015N. 8 BGS UK Hydrogeology Viewer Available online at http://mapapps.bgs.ac.uk/hydrogeologymap/hydromap.html Last accessed 20th March 2014. 9 Data from Environment Agency, available online at http://maps.environment-agency.gov.uk/wiyby/wiyby Last Accessed 17th June 2014

CPL PAGE 7-20

Rooley Moor Wind Farm Environmental Statement

naffected by mining, water quality is often very good and many springs are utilised locally as potable private water supplies.

Plate 3 Ochre deposits in spring at NGR 387186 416374

7.6.8 Groundwater Dependent Terrestrial Ecosystems 7.69. The Water Framework Directive (WFD) establishes a framework for the protection of groundwater which prevents further deterioration and protects and enhances the status of groundwater dependent terrestrial ecosystems and wetlands regardless of whether they are designated or not. Good groundwater status (both quantitative and chemical) with respect to wetlands and groundwater is dependent upon there being no ‘significant damage’ to Groundwater Dependent Terrestrial Ecosystems (GWDTE) caused by alterations to either the flow of groundwater or groundwater quality. The impact to GWDTE within the Development Area therefore needs to be considered within this ES. 7.70. There is no specific guidance relating to the identification and assessment of GWDTE habitats on wind farms in England. As a result, GWDTE habitats on Rooley Moor have been identified using methodologies outlined in UK Technical Advisory Group (UKTAG, 2009)10 and SEPA’s LUPs11 best practice guidance for identifying GWDTE and assessing those that are at risk of significant damage. 7.71. The methodology can be summarised as follows; both guidance documents advocate the identification of GWDTE through National Vegetation Classification (NVC) mapping of the proposed development area. Detailed NVC mapping of the development area has been undertaken and is fully

10 Guidance on the identification and risk assessment of groundwater dependent terrestrial ecosystems Version 5, Annex 1 (2009) Available online at http://www.wfduk.org/resources%20/risk-assessment-groundwater-dependent-terrestrial-ecosystems: Last accessed 16th June 2014 11 Land Use Planning System SEPA Guidance Note 4, version 6. Issued March 2012.

CPL PAGE 7-21

Rooley Moor Wind Farm Environmental Statement

reported in Chapter 8: Ecology. Once the mapping has been collated, each NVC community is assigned a groundwater dependency score. 7.72. The UKTAG (2009) guidance gives NVC communities a score between 1 and 3 on a scale of likely groundwater dependency with the following definitions: 1. High. Strong dependency on groundwater discharge from bedrock or superficial aquifers at the majority of sites; 2. Moderate. Likely to be some dependency on groundwater discharge at most sites – either direct from recognised aquifers or indirectly as recharge from minor aquifers in superficial deposits. Water from other sources (surface runoff, overbank flooding, etc) may also be very important; and 3. Low. Groundwater discharge usually irrelevant. Site fed by other water sources. This may also include components of ombrogenous systems with intrinsic groundwater systems fed by rain such as blanket bog. NVC communities with a score of 3 have not been taken forward in this assessment as they are not considered to be GWDTE. 7.73. Those habitats which have a GWDTE score of 1 or 2 and are located within 250m of borrow pits and turbines and/or 100m of access tracks and construction compounds are considered to be ‘at risk’ from the proposed development and therefore require assessment within an ES and may require mitigation to offset impacts. The sensitivity of these habitats is considered in Table 7.8. 7.74. NVC mapping has identified wetland plant communities such as mires, acidic flushes and bogs within the development area, these are typically located in the northern half of the site in areas underlain by varying thicknesses of peat deposits. The majority of the northern portion of the site is covered in M20, M25 and M3 habitats which are peat forming bog and mire communities and are sustained by rainwater inputs. By definition, these habitats are not groundwater dependent. In amongst the areas of bog and mire habitats, small acidic flushes (M6) and rush pasture (M23) plant communities have been mapped. These communities are considered to have some groundwater dependency and are identified as GWDTE in Table 7.8. 7.75. Non wetland plant communities such as U4, U5 grassland and U20 bracken dominate in the southern portion of the site where peat is thin or absent.

Table 7.8 GWDTE habitats within Development Area

NVC Description UKTAG 2009 Category GWDTE Score M6 – Sixteen discrete flushes of M6 covering an area of 6.26ha have been mapped 1 = High flush/mire within the Development Area. The M6 mostly forms discrete flushes orientated parallel to slope contours. All the occurrences of M6 are coincident with peat deposits suggesting outflow/seepage from this habitat is important in maintaining saturation. Other inputs will come from direct rainfall recharge, hillside runoff and shallow groundwater fluxes. The main exception is a 2.2ha polygon containing M6 and M3, an ombrogenous bog pool habitat near Prickshaw Slack. It is unlikely this M6 receives significant groundwater inputs and is likely sustained rising and falling water levels within the peat body. M23 – rush Five flushes of M23 covering an area of 2.5ha have been mapped within the 2 = Moderate pasture Development Area. These flushes are orientated parallel to slope contours to the east and west of the existing Rooley Moor track. These habitats have

CPL PAGE 7-22

Rooley Moor Wind Farm Environmental Statement

NVC Description UKTAG 2009 Category GWDTE Score formed in gullies and shallow valleys where surface water runoff flows are concentrated. Peat depths beneath these habitats are generally low (<50cm) so groundwater seepage is likely to be an important source sustaining these habitats. A 4.9ha area of M23/M25 has also been mapped. M25 is not considered to be GWDTE at this site and it is noted that both the M23/M25 polygons have formed over deeper peat which has an ombrogenous regime and are by definition, not groundwater dependent. M25 – mire The UKTAG 2009 guidance considers M25 to have a low likelihood of 3 = Low dependence on ground water movement; though in some circumstances moderate dependency is possible. The M25 within the Development Area is typically associated with peat deposits <50cm which have formed as part of an ombrogenous regime. M25 is widespread across the development area and is more associated with peat deposits than localised areas (like M6 and M23) which are more likely to be fed by groundwater seeps and flushes. It is considered that the M25 in the development area has a low groundwater dependency. U6 - The UKTAG 2009 guidance considers U6 to have a moderate dependency on 2 = Moderate grassland groundwater. M3 – bog UKTAG 2009 considers this wetland habitat to have a low dependency on 3 = Low pool groundwater as it forms as part of an ombrogenous bog regime. community M20 – raised M20 blanket bog is considered to have a low likelihood of dependence on 3 = Low mire groundwater movement (UKTAG 2009). U4 – Not a wetland habitat. Located in south of site where peat deposits are Not Wetland grassland absent. habitat so not classified. U5 – Not a wetland habitat. Located in south of site where peat deposits are Not Wetland grassland absent. habitat so not classified. U20 Bracken Not a wetland habitat. Not Wetland community habitat so not classified.

7.76. Given the local, small scale nature of the possible sensitive GWDTEs, the sensitivity of GWDTEs within the application boundary is considered to be Medium.

7.6.9 Public Water Supplies and United Utilities Assets 7.77. There are no public water supplies located within the Development Area; however, the site sits between five reservoir catchments (see Figure 7.1) which are United Utilities (UU) assets supplying drinking water to Rochdale, Rawtenstall and Bacup. These reservoirs are:

CPL PAGE 7-23

Rooley Moor Wind Farm Environmental Statement

 Greenbooth Reservoir,  Naden Reservoirs (#3),  Spring Mill Reservoir,  Prickshaw Reservoirs;  Cowm Reservoir (although understood to currently not be supplying drinking water); and  Cowpe Reservoir and Cragg High Level Tank. 7.78. In addition to the reservoirs, UU have an extensive network of silt traps and settling structures within the reservoir boundaries. These structures are generally restricted to the north of the site area between Cowpe Reservoir and Cragg High Level Tank. There is also a culvert structure feeding Cowm Reservoir from Walstead Clough in the east. 7.79. Consultation with UU indicates that deteriorating raw water quality is a concern for all reservoirs. It is understood that this is due to increased erosion of peaty soils from the Rooley moor area leading to soiley runoff into the reservoirs. UU are actively restoring peatland within their reservoir catchments, including land within or downgradient of the Development Area. 7.80. The sensitivity to public water supplies is considered to be High.

7.6.10 Private Water Supplies (PWS) 7.81. Properties with PWS within the located within 3km of the Development Area were identified through consultation with Rochdale County Council (RCC) and Rossendale Borough Council (RBC) undertaken in 2014; the consultation identified 144 properties with registered PWS. Due to the number of properties identified, a separate PWS study was completed with a view to establishing which supplies may have a direct hydraulic connection with the Development and which properties could be scoped out at an early stage. The PWS Assessment is presented as Appendix 7.1 of this chapter. 7.82. The assessment identified the following PWS as being potentially at risk from the Development. These properties are identified on Figure 7.1.

Table 7.9 PWS at Risk from Proposed Development

PWS ID Property (ies) supplied by Source Description Source Type 2 Doldrums Farm and Jubarn Well Council has advised this property is supplied by a well, abstraction volume <10m3/d. No response received to questionnaire issued April 2014. The exact nature of the source is unknown but a conservative assumption would be that the well is fed by a shallow spring which received some surface water runoff. 14 Snipe Barn Spring Property is supplied by two sources. Source 1 is spring which emerges on the hillside above the property, this spring also receives hillside runoff. This source is used for livestock and is directed into Prickshaw Dams. The second source which provides domestic water to Snipe Barn has been scoped out in the

CPL PAGE 7-24

Rooley Moor Wind Farm Environmental Statement

assessment due to the groundwater source being hydraulically remote from any influence of the proposed development. 15 Broadley Fold and Tobey Spring Spring source taken below Prickshaw Dams. Cottage Supplies Broadley Fold and possibly Tobey Cottages. 17 Lower Dunisbooth Cottage Spring Property is supplied by a shallow well intercepting a spring. The well is located 15m upgradient of the property and the supply is gravity fed into a holding tank which supplies the house. There is no water treatment. The source of the spring is unknown. The owner has stated the water contains a lot of iron and has ochre (orange) deposits in it. 23 House O’Th Hill Spring Spring See below. 24 Lower Fold Head Farm, Spring Spring up gradient of Fold Head Farm, supplies 1 Fold Head Cottages, other local properties. Spring emerges from hillside above property. The spring flows along an open 3 Fold Head Cottages channel and receives surface water runoff, including Fold Head Farm House O’Th Hill.

7.7 Baseline Sensitivity

7.83. The overall sensitivity of surface water, groundwater and geology are influenced by the sensitivity of individual receptors. This is summarised below.

7.7.1 Overall Surface Water Sensitivity 7.84. The sensitivity of the surface water environment in the Cowpe Moss, Cowm, Spring Mill and Prickshaw and Naden and Greenbooth catchments is considered to be High. This is primarily due to the presence of surface water reservoirs used for public water supply. 7.85. The sensitivity of water receptors in the Greens Moor catchment and the sensitivity of surface water PWS around the site are considered to be Medium due to the sensitivity of PWS in this catchment. 7.86. Whilst it is recognised differing receptors within the Development Area have different sensitivities, a conservative approach has been taken and an overall High sensitivity rating will be used in the assessment for all surface water receptors.

7.7.2 Overall Groundwater Sensitivity 7.87. The overall sensitivity of the groundwater environment to the Development is considered to be Medium. This is because of the good quantitative status and poor qualitative status of the NMG and PLCM aquifers. This classification also includes the presence for multiple PWS sourced from groundwater springs/wells around the site.

7.7.3 Overall Geology Sensitivity 7.88. The overall sensitivity of the geological environment to the Development is considered to be Medium. In summary, this is primarily due to presence of peat up to 2.1m depth. Much of this peat is degraded although some active areas have been identified.

CPL PAGE 7-25

Rooley Moor Wind Farm Environmental Statement

7.8 Design Evolution

7.89. The baseline assessment identified a variety of important features related to hydrology, hydrogeology and geology within the study area that are sensitive to potential adverse impacts from the Development. As a result it was recognised at an early stage that avoidance of certain areas of the Development Area would be necessary to avoid significant impacts. Of key importance during the design stage was;  The maintenance of a 50m buffer around identified watercourses so as to minimise the potential for pollution of streams and rivers through sediment mobilisation or by spills or leaks of fuel, concrete or other substances;  The maintenance of a 500m buffer around all public water supply reservoirs so as to minimise the potential for pollution of streams and rivers through sediment mobilisation or by spills or leaks of fuel, concrete or other substances;  Maintaining a safe topple distance from all United Utilities infrastructure;  The siting of infrastructure off areas with deeper peat (<50cm) where possible ;  The siting of infrastructure off areas of highly groundwater dependent habitat; and  The early identification of the sources of PWS within the study area also helped avoid these important and sensitive receptors. PWS sources were identified and tracks have been positioned at least 100m from the sources and excavations at least 250m away.

7.9 Standard Practice Measures

7.90. Standard practice measures will be implemented during construction across the Development Area, and for the construction of specific components of the Development. Some of the key best practice guidelines are referred to in Section 7.3, Policy, Legislation and Guidance. These have been taken into account when assessing the potential impact and the likelihood of significant environmental impacts and effects. 7.91. Such site-wide measures will include the following components:

7.9.1 Development of a Detailed Construction Method Statement (CMS) 7.92. Prior to construction commencing, a CMS will be produced outlining specific construction methodologies to be used for the construction of all components including foundations, tracks, watercourse crossings, laydown areas and buildings, taking into account the method of excavation and the location for placing and storing excavated material to ensure that these operations do not give rise to slope or site instability. A CMS will be provided with the Construction Environmental Management Plan (CEMP).

7.9.2 Development of a Construction Environmental Management Plan (CEMP) 7.93. Prior to construction commencing, a detailed CEMP will be produced. A draft CEMP has been prepared as part of this application and is presented as Appendix 4.1. Good working practices and measures to protect the water environment in accordance with those set out within the EA and CIRIAs’ PPG notes will be implemented. The Principal Contractor will be responsible for ensuring that the plan is adhered to during construction. As well as a commitment to and details of best practice, this will address specific mitigation measures (in addition to standard practice measures). This

CPL PAGE 7-26

Rooley Moor Wind Farm Environmental Statement

document will be presented Rochdale Council, Rossendale Council, the EA and United Utilities for their approval, prior to construction commencing. 7.94. Specific elements with direct relevance to this chapter that will be included in the CEMP are:  Emergency and Incident Response Plan for any pollution events/spills;  An inventory of pollution sources associated with construction and specific pollution prevention;  Measures to reduce the likelihood of contamination from identified sources to downgradient surface watercourses from fuels, oils and other contaminants. Control measures described in EA PPG notes and CIRIA guidance will be formalised within the CEMP;  A waste management plan;  Proposed measures for noise management;  Watercourse crossing plans; and  Details of excavation and reinstatement.

7.9.3 Drainage Management Plan (DMP) 7.95. There is potential for the generation of turbid or coloured runoff from works areas throughout the Development Area including the construction of turbines, tracks, watercourse crossings, borrow pits, buildings and other infrastructure to enter surface watercourses and waterbodies particularly via drainage channels or watercourses that are directly adjacent to or downgradient of works. Therefore a DMP will be put in place, which will form part of the CEMP. An outline DMP has been prepared and is presented as Appendix 4.4. This will provide a range of site-wide measures to reduce the generation of sediment laden or coloured runoff and transport of any runoff to watercourses. Further specific mitigation measures which are in addition to best practice measures outlined in this section will be included in this plan. 7.96. The DMP will consist of the following:  A series of plans presenting the site infrastructure, existing natural drainage patterns and man-made drainage structures;  Geology for assessment of likely permeability and infiltration;  Sensitive receptors including distance to watercourses, PWS;  Topography;  A description of the drainage considerations, sensitive areas of the site, procedures and control structures to be employed for the various sections of the site;  A layout of the required drainage arrangements, upgradient diversion channels, culvert frequency, H bars on tracks, check dams, silt fencing and other sediment control structures; and  An appendix of the methodology for the installation of the sediment control structures.

7.9.4 Water Quality Monitoring 7.97. Water quality will be monitored upstream and downstream of key construction works prior to, during and following construction. Monitoring locations will take account of the construction of watercourse crossings, access tracks, turbine foundations and borrow pits and will also take place at control sites (outside the influence of works). A robust baseline of water quality in surface watercourses/drainage channels downstream of construction works will be established prior to construction commencing. The

CPL PAGE 7-27

Rooley Moor Wind Farm Environmental Statement

purpose of this is to provide a comparison of ‘natural’ conditions against conditions potentially impacted by construction. Regular monitoring during construction and in the early phases of operation will be used to ascertain whether there are impacts occurring to watercourses and whether implemented mitigation measures are being effective. During the early phase of operation, monitoring will continue to assess the quality of watercourses, comparing against baseline data. The plan will include specific actions to be taken upon triggering environmental standards. 7.98. An agreement in principal has been reached with UU over the proposed water quality monitoring and how this monitoring can interface with and mutually enhance and/or be enhanced by proposed and ongoing water quality monitoring in support of peat restoration schemes sponsored by UU. More detail about the peatland restoration schemes are contained within Chapter 8: Ecology.

7.9.5 Provision of an Environmental Clerk of Works (ECoW) 7.99. An ECoW will be appointed to undertake/manage the following tasks during construction:  Implementation of peat minimisation protocol (refer to the outline PMP in Error! Reference source not found.);  Oversee the implementation of the Habitat Management Plan (HMP) (refer to the outline HMP in Chapter 8: Ecology);  Operate permit to dig and permit to pump systems, etc;  Water quality monitoring;  Emergency response;  Monitor drainage and sediment control; and  Monitor and ensure compliance with best practice guidance. 7.100. In addition to the above key best practice tools, individual infrastructure best practice and standards are discussed below.

7.10 Predicted Impacts

7.101. When assessing predicted impacts of the Development standard practice measures that will be incorporated into the construction of the wind farm have been taken into account. In addition the measures that were taken during the design phase to avoid areas sensitive to potential impacts have significantly reduced the potential impacts arising from the Development. 7.102. Whilst the incorporation of these measures/design features helped to reduce the magnitude or likelihood of some potential impacts occurring, it was not possible to avoid all potential impacts. The potential significant impacts of the Development during construction, operation and decommissioning prior to specific mitigation measures being applied are summarised in Table 7.12.

7.10.1 Construction Access Tracks

7.103. The Development incorporates an estimated 6.8km of new tracks. With the exception of watercourse crossings, new sections of access tracks have been located a minimum distance of 50m from the OS mapped watercourses on the site. The construction of watercourse crossings will be within this buffer and the risks associated with these works are addressed in the Watercourse Crossings (Section 0) section below. New tracks are proposed to be constructed within the following catchments:

CPL PAGE 7-28

Rooley Moor Wind Farm Environmental Statement

 Spring Mill and Prickshaw;  Naden and Greenbooth;  Cowm; and  Greens Moor; 7.104. There are no new tracks proposed in the Cowpe Moss catchment. 7.105. Construction of access tracks and their continued use during the construction phase may potentially generate turbid runoff, which could follow topographic grades to surface watercourses and associated receptors. Any potential impacts to surface watercourses are expected to be localised and short term only. Pollution prevention and sediment and drainage control measures described in EA PPG notes and CIRIA guidance will be formalised within the CEMP; a draft CEMP is presented as Appendix 4.1.The contractors will be required to comply with this document. The document will specifically outline how surface water runoff will be managed during construction. Design of drainage will seek to mimic existing local surface water runoff regimes, such that there will be no change in quantity of runoff into downstream receiving watercourses. 7.106. The routes of access tracks are confined to the top of sub-catchment areas, crossing watershed areas of the sub-catchments identified above. Construction of access tracks and their continued use during the construction phase may potentially generate turbid runoff, which could follow topographic grades to surface watercourses, waterbodies and associated receptors, resulting in a temporary decrease in water quality. Any potential effects to surface watercourses are expected to be localised and short term only. Design of drainage as outlined in Appendix 4.4 will seek to mimic existing local surface water runoff regimes, such that there will be no change in quantity of runoff into downstream receiving watercourses. 7.107. The access tracks are located well over 100m from all PWS, however, there may be some impacts to water quality at PWS. The source of the impacts will be restricted to the upgraded section of the existing track as no new tracks are proposed directly upgradient of PWS supplies. 7.108. Overall, the peat slide risk across the site is generally low, however, localised medium risk areas of peat instability have been identified (see Figure 12 of Appendix 7.3) and adequate control measures will need to be incorporated during construction works to protect any vulnerable watercourses. A peat slide caused as the result of access track construction could result in the release of peat sediments into down gradient watercourses. Tracks will be either of ‘excavated’ type tracks, (estimated 5.0km) constructed on areas with less than 1.0m depth or ‘floating’ type tracks (estimated 1.8km) constructed on areas of peat greater than 1.0m depth. This track design minimises the volume of peat excavated during construction, minimises the mobilisation of peat fines from excavation areas and preserves unimpeded subsurface flow. 7.109. The track layout has been designed to avoid areas of active peat, however total avoidance has not been possible. The new access track is proposed in areas of active bog to provide access to turbines T18, T16, T15 and T14. The track could disrupt hydraulic continuity within the bog habitat, resulting in indirect loss down gradient of the track. These indirect losses of habitat could occur if hydraulic continuity is not maintained down gradient of the access track. 7.110. The access track layout has avoided all areas of highly groundwater dependent habitats (M6). Upgraded sections of access track along Rooley Moor road to cross areas of M23, moderately dependent GWDTE. The presence of tracks can disrupt shallow groundwater flows, impounding water on the upgradient side of track, resulting in indirect habitat loss up to 100m from tracks. However, as this M23 is already located on either side of the track, this suggests its presence is unaffected or even enhanced by the presence of the track. One area of new track, near water crossing no.4 (see Section

CPL PAGE 7-29

Rooley Moor Wind Farm Environmental Statement

0) will bisect a flush of M23 which leads onto a flush of M6. Mitigation will be required to ensure hydraulic continuity is maintained at this point and maintain GWDTE habitats down gradient. 7.111. Furthermore, indirect loss of the above mentioned habitats could occur as a result of the access track construction. Impacts relating to direct loss of ecological habitat are covered in Chapter 8: Ecology. Watercourse Crossings

7.112. There are a total of two new and one upgraded watercourse crossing proposed to be constructed over surface watercourses and drainage channels within the Development Area, shown on Figure 7.1 and described in Table 7.10. These crossings are proposed in the following catchments:

Table 7.10 Proposed and Upgraded Water Crossings

Crossing Type Location Catchment Description ID (NGR) 1 Upgraded 386948 Spring Mill and Upgraded watercrossing beneath existing Rooley 416085 Prickshaw Moor Road. No direct discharge to reservoir. 2 New 385631 Naden and New crossing over stream which discharges 418048 Greenbooth directly into the Naden and Greenbooth Reservoir. 3 New 385665 Naden and New crossing over stream which discharges 418086 Greenbooth directly into the Naden and Greenbooth Reservoir. Upgradient of crossing 2.

7.113. During the construction of all watercourse crossing culverts, potential impacts include:  Constriction of fluvial flow resulting in increased flood risk;  Disturbance to stream banks and/or substrate which could lead to increased erosion and local changes to fluvial geomorphology, direct loss or damage to aquatic habitats or species or a local increase in suspended sediment concentrations causing a temporary decrease in local water quality;  Disturbance to stream banks and shallow groundwater flows, resulting in indirect loss or degradation to adjacent/down gradient GWDTE habitats;  Sediment contamination of the watercourse from plant movement near the works; and  Spillages or leaks of other contaminants such as fuels or oils which could enter the watercourse. Wind Turbine Foundations and Crane Hardstandings

7.114. The Development includes the construction of 12 wind turbines and associated crane hardstandings. Turbines are proposed to be constructed in the following surface water catchments:  Naden and Greenbooth catchment (9);  Watershed of Naden and Greenbooth and Spring Mill and Prickshaw catchment (1); and  Greens Moor catchment (2). 7.115. To reduce the potential for turbid runoff or other contaminants such as fuels or oils (used in construction) from entering surface watercourses, wind turbines and associated crane hardstandings have all been located a minimum distance of 50m away from all OS mapped watercourses. The wind turbines will be supported on concrete foundations, measuring up to 3m in depth and up 20m width, (see Figure 4.3). Construction of the turbine foundations will involve the excavation of peat and

CPL PAGE 7-30

Rooley Moor Wind Farm Environmental Statement

subsoil, which will either be bunded and stored prior to the in-situ casting of a steel-reinforced concrete slab. Surplus peat will be used for habitat restoration (see the outline PMP in Appendix 7.2), and to batter the edges of tracks and platforms, or landscaping local to each turbine. Excavation areas will have sides that are 'battered' back to ensure that they remain stable during construction. Each foundation is expected to require approximately 390m3 of concrete and 55 tonnes of steel reinforcing. Hardstanding areas will be constructed adjacent to each turbine, orientated to make best use of topography and prevailing wind conditions, with an area of approximately 25m by 40m (33m by 40m, if turbine is located at the end of an internal track). 7.116. There is potential for concrete spillages during turbine foundation construction, which could migrate into groundwater or to down gradient surface water features. Concrete is highly alkaline and corrosive and any spillage can adversely affect water quality. Concrete is only mobile for a short period of time before it sets and therefore the potential for migration of concrete into groundwater would only occur for a short duration until it begins to set. 7.117. The areas of unconfined bedrock aquifers may be at risk of contamination from concrete in the event of a spillage. The potential risk will be confirmed by an intrusive ground investigation prior to works commencing. Controls will be required to prevent mobilisation of any concrete spills overland to surface water features and into groundwater. 7.118. It is recognised that not all turbines are situated on topographical high points and some turbine locations will be subject to ephemeral surface runoff pathways which will convey runoff during rainfall events during construction. A draft Drainage Management Plan (DMP) is presented as Appendix 4.4 and a final DMP will be presented post consent, prior to any construction activity. This document will describe how to manage flows across the Development Area during construction and this will include management of flows at each turbine location, during and post construction. This plan will take into account the potential for flows from up gradient areas as well as managing runoff from the turbine location. Design of drainage will seek to mimic existing local surface water runoff regimes, such that there will be no change in quantity of runoff into downstream receiving watercourses. 7.119. When excavating for construction of the turbine foundations, it is possible that groundwater will be encountered. Excavations may need to be dewatered to lower groundwater levels and ensure that wet working and direct contact of cement material with groundwater does not occur. This will mean that there is potential for loss of recharge and interruption of existing groundwater regimes in the immediate locality. 7.120. The impact on any PWS is not expected to be significant as the placement of turbines has avoided PWS sub-catchment areas. 7.121. The PSRA (Appendix 7.3) identifies areas of moderate peat slide risk located close to Clegg ding, Red Pits and the Top of Leach; these have been largely avoided where practical. Turbines T4 and T8 are located in areas of moderate peat slide risk and turbine T10 is located on the up gradient periphery of an area of moderate risk. A peat slide in this location has the potential to cause a release of peat sediments into the Naden and Greenbrook catchment resulting in a significant reduction in surface water quality. Additional mitigation will be required to reduce the risk of peat slide in this area. 7.122. The majority of turbines have been located off areas of deeper peat and active bog. The placement of turbines T18, T16, T15 and T14 are in areas of M3 bog pool community which is considered to be active. The placement of the turbines will result in direct loss of habitat (considered in Chapter 8: Ecology). During the construction phase, turbine foundation excavations will locally dewater the peat body and physically deteriorate the peatland structure leading to erosion and runoff pf peat mater into downstream water bodies. The continued presence of turbines during the operational phase will also result in disruption to hydraulic continuity in the peat body. Mitigation will be required to ensure

CPL PAGE 7-31

Rooley Moor Wind Farm Environmental Statement

disruption to this habitat is minimised and secondary impacts, such as peat drying and erosion are effectively managed. 7.123. The placement of turbines has avoided all moderate and highly groundwater dependent habitats and therefore there will be no impact to these receptors. Electric Cables

7.124. Electric cables for the Development will be installed within small trenches (approximately 1.8m wide and 0.5m deep) that will run alongside the access tracks. The majority of the cable route will be located on bedrock, with some shorter sections crossing areas of peat. 7.125. There is potential for cable trenches to transport turbid water from works areas to drainage channels and surface watercourses down gradient. Substation Compound and Control Building

7.126. The proposed location of the control building and substation compound is shown on Figure 4.9. The building will be situated within a 35m x 25m compound, incorporating car parking and storage yard. The control building and substation compound will be located in the south of the site and built directly onto the PLCM bedrock, there is no peat in this area. As a result, there will be no significant impact on peat. 7.127. Both the substation and control buildings are located over 50m up gradient of the nearest watercourse which flows towards the east through the Snipe Barn Farm PWS sub-catchment. During the construction phase, excavation of bedrock and soils stripping may generate sediment laden runoff. Furthermore, any spillages of concrete or other contaminants such as fuel or oils may impact upon groundwater quality. 7.128. It is unlikely that the excavation of foundations would result in any significant dewatering as foundation depths are estimated to be up to a maximum of 1.0m below ground level. Temporary Construction Compound

7.129. An indicative layout for the construction and laydown compound is shown in Figure 4.10. The compound will have dimensions of approximately 85m x 65m. The area will be prepared by carefully stripping soil and peat in accordance with best practice guidance, laying down geotextile material and then a working surface of stone. The stripped material will be stored adjacent to the site for subsequent use in reinstatement and screening. Borrow Pits

7.130. Borrow pits will be constructed to provide stone for the wind farm infrastructure. No stone will be bought onto site. The proposed borrow pit locations have been selected because of their morphology, accessibility from existing or new access tracks, orientation and the expected proximity of rock to the surface. It is proposed to construct two borrow pits, details are listed in Table 7.12 below.

Table 7.11 Borrow Pit Details

Borrow Pit ID Location Surface Area Max Depth Volume Extracted Borrow Pit 1 386458, 416930 250m x 68m 3.5m 40,000m3 Borrow Pit 2 386104, 417915 137m x 105m 7m 60,000m3

CPL PAGE 7-32

Rooley Moor Wind Farm Environmental Statement

7.131. Without appropriate mitigation measures the construction of borrow pits results in the following potential to impacts to water resources by:  Excavating and disruption of peat resources;  Disruption of groundwater storage and flow through excavation below the water table;  Generation of suspended solids to surface water;  The disruption to established drainage patterns through extraction/stockpiling activities; and  Surging of surface run off which has collected in excavated borrow pit areas. 7.132. Upon completion, the borrow pits will be partially reinstated. This will involve the reworking of faces to stabilise them, partial infilling with surplus material and landscaping with peat (where there was originally peat habitat) and soils excavated during the wind farm construction. There may also be the potential for environmental enhancement by creating small wetlands or other desirable habitats.

7.10.2 Operation 7.133. This section provides a summary of potential impacts prior to mitigation measures being implemented, but on the basis that good site practices will be employed. It is based on an assessment of activities that will occur during the operational phase of the Development which are presented below. 7.134. The potential impacts (and the likelihood of them occurring) to identified sensitive receptors during the operational phase are summarised in Table 7.12, along with an assessment of their significance. Access tracks and Watercourse Crossings

7.135. The tracks are designed to last for the life of the Development and only limited maintenance is envisaged during operation. The tracks will be constructed from compressed aggregate, which could be eroded by surface water over time. There will be low volumes of traffic throughout the operational phase (see Chapter 12 Access, Traffic and Transport). 7.136. Potential effects during operation of the Development from the presence of access tracks and watercourse crossings include:  Increased sediment loading in surface watercourses from runoff from tracks caused by traffic movement or the erosion of tracks;  The potential for spills and leakages of potentially polluting substances such as fuels and oils from plant and vehicles which could migrate to surface watercourses or groundwater;  Increased flood risk due from watercourse crossings and tracks; and  Change in local groundwater flow regimes with may reduce recharge to sensitive areas located down gradient of tracks. 7.137. The likelihood of spillages or leaks of fuels or oils will be much reduced during the operational phase, compared with during construction. Sources will be limited to fuel from vehicles visiting the Development Area, lubricants and oils used in the turbines substation and transformers and foul drainage produced by the limited numbers of staff visiting the application site. To further reduce the likelihood of spills occurring and to reduce any impacts if spills do occur, similar best practice measures that were applied during construction will be implemented. 7.138. All tracks and watercourse crossings are outside floodplain areas, however their presence has the potential to increase flood risk during the operational phase. The presence of tracks will slightly decrease the overall permeability of the Development Area, resulting in slight increases in runoff rates

CPL PAGE 7-33

Rooley Moor Wind Farm Environmental Statement

during rainfall events. However, even when combined with other hardstanding areas within the Development Area, the increase in hardstanding area represents negligible proportion of the total area of the surface water catchments within and downstream of the application site. Therefore, the presence of tracks is unlikely to result in a measurable increase in surface water runoff rates from the Development Area. 7.139. Watercourse crossings have the potential to constrict the watercourses resulting in flows backing up and increasing the risk of flooding upstream. The design of watercourse crossing culverts will reduce the likelihood of channels becoming constricted or crossings becoming blocked, with the actual design of crossings to be agreed at the detailed design stage. Control Building, Substation and Hardstanding Areas

7.140. Potential impacts from the control building, substation building and hardstanding areas during operation are not considered to be high or likely. The buildings will be visited infrequently during operation of the wind farm and are located outside of a floodplain area. The small quantity of sewage arising from visits of maintenance staff will be stored in septic tanks and removed periodically by a licensed contractor. 7.141. Rainwater collection systems would be installed to provide water for flushing which, if necessary, would be topped up with water brought to site in containers. Excess rainwater falling on the roof of the buildings will be discharged to an infiltration drain or other SUDS based drainage system around the compounds. The buildings will not be of a size to intercept significant quantities of water and no impact is expected to groundwater/surface water at the application site. 7.142. No impacts are anticipated as a result of the presence of this infrastructure. Wind Turbines, Foundations and Crane Hardstandings

7.143. The physical presence of turbine foundations may locally change groundwater flow regimes. Runoff over turbine bases will be directed back to undisturbed ground using toe drains where necessary, and there will be a negligible loss of recharge. Cut-off drains will also be used to direct runoff to ground. These measures will be designed not to act as preferential migration pathways. 7.144. The impact on any PWS is not expected to be significant as the placement of turbines has avoided PWS sub-catchment areas. 7.145. In addition there is the potential to decrease the water quality of down gradient surface watercourses due to spills or leaks from oil or other potentially polluting substances. However, the likelihood of this occurring is low and volumes of any spills are not expected to be substantial. To reduce the likelihood of spills or leaks from turbines, each turbine will be designed with fluid catch basins and containment systems to prevent accidental releases from leaving the nacelle. Any accidental gear oil or other fluid leaks from the wind turbines would be contained inside the towers as they are sealed around the base, with the entrance situated above ground level. 7.146. The design of the foundations will ensure that there are no water quality impacts to downstream surface watercourses or groundwater from the use of concrete. Foundations will be constructed using sulphate resistant concrete, which will ensure no degradation or subsequent pollution when in contact with acidic water during the lifetime of the Development. 7.147. The reinstatement of the turbine foundation area (comprising back filling the foundation area over the subsurface foundations with excavated soil and re-vegetating to allow for the natural infiltration of surface water) will assist in the reinstatement of groundwater recharge mechanisms and will ensure no significant change to overall groundwater regimes.

CPL PAGE 7-34

Rooley Moor Wind Farm Environmental Statement

Borrow Pits

7.148. Borrow pits will have been decommissioned and partially reinstated in the construction phase so no impact is expected during this phase.

7.10.3 Decommissioning 7.149. The Development will have a planned operational life of up to 25 years. At the end of this period, unless permission for continued operation as a wind farm is granted, it will be decommissioned. The ultimate decommissioning methods will be agreed with Rochdale Metropolitan and Rossendale Borough Councils and other appropriate regulatory authorities (e.g. DEFRA, Natural England). The site will be reinstated post decommissioning through a programme of habitat restoration, in accordance with an agreed decommissioning plan. 7.150. It can be anticipated the decommissioning process will comprise:  Wind turbines: To be dismantled, removed from the site and disposed of appropriately;  Foundations: The majority will be left in-situ. The top metre of the base will be removed and disposed of appropriately. The area re-surfaced with topsoil or peat and restored appropriately;  Underground cabling: These will be left in-situ or removed for recycling;  Access tracks and hardstandings: These will be left in-situ to be used by the landowner;  Water Crossings: these will be left in suit as they are integrated into access tracks;  Anemometry masts: These will be dismantled, removed from the site and disposed of appropriately. The foundations will remain in-situ. The top metre of the base will be removed, disposed of appropriately, then covered with top soil or peat and restored;  Site access: All access tracks will be left in-situ; and  Wind farm control building, substation and compound: The equipment will be removed and disposed of appropriately. The building will be demolished and the material removed from the site. The top 1m of the foundations will be removed then covered over with topsoil or peat and restored appropriately. 7.151. Potential impacts during the decommissioning phase will reflect the impacts predicted for construction, however substantially less activity is anticipated during this period. There will be some limited earthworks associated with the removal of turbines, buildings and the anemometry masts. The removal of site infrastructure has the potential to cause a temporary decline in water quality from the generation of turbid runoff migrating to down gradient surface watercourses and associated receptors, and it is assessed that the likely potential impact would be moderate. 7.152. There is also potential for minor impacts associated with a temporary decrease in water quality from spills or leakage of fuels, oils or other potentially polluting substances from vehicular and plant movement on site, the storage and use of chemicals and the maintenance of plant. To reduce the likelihood of spills occurring and to reduce any impacts if spills do occur, similar best practice measures that were applied during construction will be implemented.

7.11 Summary of Potential Impacts and Mitigation Measures

7.153. Potential impacts prior to mitigation during construction, operation and decommissioning are summarised in Table 7.12 Summary of Predicted Impacts. An indication of whether additional mitigation is required or not is also included.

CPL PAGE 7-35

Rooley Moor Wind Farm EIA

Table 7.12 Summary of Predicted Impacts

Magnitude of Evaluation Likelihood Likely Sensitivity Mitigation Activity Potential impact Receptor potential of potential of potential of receptor required? impact impact occurrence impact CONSTRUCTION A temporary decrease in water quality from the generation of turbid or Surface water Construction discoloured runoff (all surface of site High Moderate Moderate Possible Moderate  migrating to down infrastructure water gradient surface catchments) watercourses and associated receptors Surface water (Springmill & Disturbance to stream Prickshaw, banks causing changes in Naden & High Medium Moderate Likely Moderate  erosion rates and local Greenbooth morphology Construction catchments of only) watercourse Surface water crossings (Springmill & Blockage or constriction of Prickshaw, watercourses causing an Naden & High Medium Moderate Possible Moderate  increase in flood risk Greenbooth catchments only) Construction Increase in runoff rates Surface water of causing an increase in (all surface High Low Minor Possible Minor  hardstanding flood risk water areas such as

CPL PAGE 7-36

Rooley Moor Wind Farm EIA

Magnitude of Evaluation Likelihood Likely Sensitivity Mitigation Activity Potential impact Receptor potential of potential of potential of receptor required? impact impact occurrence impact tracks, catchments) compounds, turbine foundations and buildings. Vehicular and Surface water plant (all surface High High Major Possible Moderate  movement A temporary decrease in water onsite; water quality from spills or catchments) storage and leakage of fuels, oils or use of oils and other potentially polluting chemicals; substances Groundwater Medium Medium Moderate Likely Moderate  maintenance of plant Groundwater Disruption of PWS and Surface Medium Medium Moderate Rarely Negligible  supplies water Construction Disruption to peat of the access hydrology and consequent Geology Medium Medium Moderate Likely Moderate  tracks and degradation of peat turbine foundations Decrease in water quality Surface water of watercourses located (all surface High Medium Major Rarely Minor  down gradient of a peat water slide occurrence. catchments) Dewatering of A temporary decrease in Surface Water (Springmill and groundwater water quality from the High Medium Major Possible Moderate  in the generation of turbid runoff Prickshaw construction migrating to down only)

CPL PAGE 7-37

Rooley Moor Wind Farm EIA

Magnitude of Evaluation Likelihood Likely Sensitivity Mitigation Activity Potential impact Receptor potential of potential of potential of receptor required? impact impact occurrence impact of foundations gradient surface water and borrow receptors including PWS pits Loss of groundwater recharge and change of local groundwater regimes Groundwater Medium Medium Moderate Likely Moderate  potentially causing indirect loss of PWS Disruption to peat hydrology and draining of Geology Medium High Moderate Likely Moderate  peat Excavation of peat during the Disturbance and Geology Medium Medium Moderate Likely Moderate  construction degradation of peat of site infrastructure OPERATION A temporary decrease in water quality from the Surface water generation of turbid runoff Vehicular use (all surface migrating to down High Medium Major Rarely Minor  of tracks and water gradient surface watercourse catchments) crossings / watercourses and other site associated receptors activities A temporary decrease in Surface water water quality from spills or (all surface High Medium Moderate Possible Minor  leakage of fuels, oils or water

CPL PAGE 7-38

Rooley Moor Wind Farm EIA

Magnitude of Evaluation Likelihood Likely Sensitivity Mitigation Activity Potential impact Receptor potential of potential of potential of receptor required? impact impact occurrence impact other potentially polluting catchments) substances Groundwater Medium Low Low Rarely Negligible  Presence of Blockage or constriction of watercourse watercourses causing an Surface water High Low Moderate Rarely Minor  crossings increase in flood risk Changes to local groundwater flow regimes resulting in drying out of Geology Medium Low Minor Likely Minor  Presence of peat resources down turbine gradient foundations Changes to surface water runoff patterns and rates Surface water High Low Moderate Rarely Minor  which could increase flood risk A temporary decrease in Surface water High Medium Moderate Rarely Minor  water quality from spills or Use of control leakage of fuels, oils or building and other potentially polluting substation Groundwater Medium Medium Low Rarely Negligible  substances such as sewage Reinstatement of borrow Reinstatement  (positive pits with peat to create Geology Medium Medium Moderate Likely Moderate of Borrow pits effect) new bog wetland areas DECOMMISSIONING A temporary decrease in Removal of water quality from the Surface water High Medium Major Possible Moderate  site generation of turbid runoff

CPL PAGE 7-39

Rooley Moor Wind Farm EIA

Magnitude of Evaluation Likelihood Likely Sensitivity Mitigation Activity Potential impact Receptor potential of potential of potential of receptor required? impact impact occurrence impact infrastructure migrating to down gradient surface watercourses and associated receptors Vehicular and Surface water High Medium Major Possible Moderate  plant movement A temporary decrease in onsite; water quality from spills or storage and leakage of fuels, oils or use of oils and other potentially polluting Groundwater Medium Medium Low Rarely Minor  chemicals; substances maintenance of plant

CPL PAGE 7-40

Rooley Moor Wind Farm Environmental Statement

7.12 Mitigation Measures

7.12.1 Access Tracks 7.154. Tracks will be either of ‘excavated’ type tracks (estimated 5.0km proposed), constructed on areas with less than 1.0m depth of peat, or ‘floating’ type tracks (estimated 1.8km proposed) constructed on areas of peat greater than 1.0m depth. This design of tracks is proposed in order to minimise the volume of peat excavated during construction, minimise the mobilisation of peat fines from excavation areas and preserve unimpeded groundwater flow. 7.155. Construction of access tracks and their continued use during the construction phase may potentially generate turbid runoff, which could follow topographic grades to surface watercourses and associated receptors. Any potential impacts to surface watercourses are expected to be localised and short term only. Pollution prevention and sediment and drainage control measures described in EA PPG notes and CIRIA guidance will be formalised within the CEMP. The contractors will be required to comply with this document. The document will specifically outline how surface water runoff will be managed during construction. 7.156. Trackside drains will be provided to control runoff from construction areas especially during heavy rainfall events. Trackside drainage will comprise either buffer strips or infiltration trenches which will be unlined to allow the standing water to infiltrate back into the ground. Tracks will have a camber to encourage runoff adjacent to trackside drains. The drains will have the potentially to convey entrained sediments within runoff and will discharge into a swale or buffer area of adequate capacity to prevent discharge directly into any surface watercourse. There will be no direct discharge of construction drainage to any existing watercourse. 7.157. To mitigate any potential reduction to groundwater recharge from track construction and to allow the passage of any sub-surface flows, constructed tracks will comprise a semi-permeable surface to allow some infiltration. 7.158. To limit potential pollution impacts from either hardcore and/or excavated material entering watercourses, or increased sediment levels within surface water runoff, the principle contractor will be required to adhere to measures and controls set out in the CEMP and PMP during construction. These measures will include, but not be limited to:  Any excavated soil/peat that will be used in the construction of access tracks (e.g. to dress the sides of the tracks once backfilled) are to be temporarily placed on the furthest side away from any identified watercourse or drain;  The provision of buffer strips around watercourses or drainage channels on sections of track adjacent to watercourse crossings;  Procedures during excavations and soil handling for both routine working and during any environmental emergencies to control and mitigate both erosion and dust generation; and  Trackside ditches will be unlined to allow water to soak back into the ground resulting in no significant loss to groundwater recharge. 7.159. The degree of disturbance and degradation of peat resources has been minimised in the design of the track. This has minimised the direct loss of peat resources. Further details regarding the excavation, storages and reinstatement procedures are presented in the outline PMP (Error! Reference source not found.). The majority of the site’s access tracks will be constructed using a cut and fill methodology. Excavated peat from cut and fill sections of access tracks will be used for dressing the side slopes of track sections and potentially for landscape screening bunds. Peat turves will also be replaced on constructed roadside drainage channel embankments where possible. Only peat turf and fibrous peat is likely to be suitable for battering road verges. When constructing tracks rapid restoration will be undertaken as track construction progresses. Immediately following construction some turves will be replaced along the road edges to allow quicker re-vegetation and soften the road edges

CPL PAGE 7-41

Rooley Moor Wind Farm Environmental Statement

7.160. The design and construction of tracks on peat will be done in such a way so as to reduce impacts on and maintain the existing peat hydrology at the site. The built track will allow for the transmittance of water, so natural drainage can be maintained as much as possible. 7.161. Floating tracks avoid the need to excavate the peat and re-fill with imported rock. However, the weight of the track structure can cause compression of the underlying acrotelm resulting in reduced transmittance of water, resulting in pond of water upgradient of tracks and derogation of water supply down gradient of tracks. Drainage through the floating track will be maintained using drains constructed at regular points through the peat.

7.12.2 Watercourse Crossings 7.162. All watercourse crossings on site are considered to be minor crossings (i.e. narrow watercourse, relatively flat gradients, low velocity flows), all of which will be crossed via culverts. It is proposed these crossings will be formed from plastic or pre-cast concrete culverts, with the size based on the calculation of peak flow from the upstream catchment to enable a 0.5% AEP flow (including an allowance for climate change on future rainfall intensities) to be passed through the culvert. The actual design of each culvert will be agreed at the detailed design stage, with all culverts designed and constructed in accordance with EA and CIRIA good practice guidance and the designs agreed with EA prior to construction. The design of each crossing will take into consideration overland flow routing in the event of a blockage and to enable flow to be directed back into the watercourse downstream of any obstruction. 7.163. It is proposed culverts will be embedded so that the base is at grade with the streambed or lower to maintain bed form processes and minimise disruption to wildlife migration. The need for ledges to enable the movement of mammals through the pipe will be assessed at the design stage and incorporated as necessary. 7.164. Disruption to channel banks during the construction of crossings will be minimised by the use of cofferdams and over-pumping if the channel exhibits potential for high flows during the construction period. Pollution prevention measures as outlined in the CEMP will be implemented to reduce the likelihood of sediment or other contaminants entering adjacent watercourses

7.12.3 Wind Turbine Foundations and Hardstandings 7.165. To reduce the potential for turbid runoff or other contaminants such as fuels or oils (used in construction) from entering surface watercourses, wind turbines and associated crane hardstandings have all been located a minimum distance of 50m away from all OS mapped watercourses. 7.166. It is recognised however not all turbines are situated on topographical high points and some turbine locations will be subject to ephemeral surface runoff pathways which will convey rainfall runoff during rainfall events. A site drainage plan will be specified within the CEMP to manage flows across the site and this will include management of flows at each turbine location, during and post construction. This plan will take into account the potential for flows from up gradient areas as well as managing runoff from the turbine location. 7.167. When excavating for construction of the turbine foundations, it is possible that groundwater will be encountered. If this occurs, excavations will be dewatered to lower groundwater levels and ensure that wet working and direct contact of cement material with the groundwater does not occur. This will mean that there is potential for loss of recharge and interruption of existing groundwater regimes in the immediate locality, potentially affecting sensitive peat habitats. Any water will be pumped out and passed to a settling lagoon to allow suspended sediment to settle. Treated water will be discharged to an area of vegetated ground designated for drainage allowing seepage into the ground. There will be no direct discharge of pumped groundwater to adjacent watercourses or drainage channels. Further details on this will be included within the CEMP and will be agreed with the EA prior to construction commencing.

CPL PAGE 7-42

Rooley Moor Wind Farm Environmental Statement

7.168. Excavations will remain open for the shortest time practical to limit the effect of any dewatering. There will be no discernible overall loss of recharge to groundwater; however some areas will experience minor localised change to flow regimes through excavations and the introduction of turbine foundations. Recharge from drainage channels will compensate for localised reduction in infiltration as a result of the presence of the foundations acting as a barrier to groundwater flow. 7.169. There is potential for concrete spillages during turbine foundation construction, which could migrate into groundwater or surface water. Concrete is highly alkaline and corrosive and any spillage can have adversely affect water quality. To minimise the likelihood of spillages, concrete will be brought to site ready mixed and the wagons will enter and leave the site through a designated site entrance, and all vehicle washouts will take place off-site. Temporary bunds will be placed downslope of pouring operations to contain any spillages. In the event of a spillage, an incident and emergency response plan will be initiated. This will be detailed in the CEMP. 7.170. It is understood that migration of concrete in groundwater can occur in highly fractured and fast flowing groundwater environments (Environment Agency, 2001). Prior to pouring concrete within turbine excavations, the degree of weathering or fracturing of bedrock will be assessed. If the bedrock is highly fractured, it may be necessary to form a barrier within the excavation to ensure liquid concrete does not come into contact with underlying groundwater. Either a geotextile liner or a sand layer would restrict the flow of concrete into the surrounding groundwater. This will be determined by an intrusive ground investigation prior to works commencing. It should be noted that once concrete is poured it is only mobile for a short period of time before it sets and therefore the potential for migration of concrete in such groundwater conditions would only occur for a short duration until it begins to set. 7.171. Measures of the disturbance and degradation of peat resources during and after the construction of turbine foundations and hardstanding areas are detailed in the outline PMP (Error! Reference source not found.). It is envisaged that the majority of the excavated peat materials from turbine foundation excavations will be reused for the purpose of borrow pit restoration, which will be restored to create bog habitats. Some peat will be replaced around the turbine base excavations, and re-turfed. Peat will also be spread over the areas disturbed by turbine construction activities, around the crane hardstandings, rotor assembly hardstandings and other areas used in the construction phase. Where appropriate, excess peat turves may be used for screening bunds, landscaping or as material for use as part of the HMP, in conjunction with reseeding.

7.12.4 Substation Compound and Temporary Construction Compound 7.172. During construction of the substation and temporary construction compounds, a surface layer of vegetation and topsoil will be removed and a shallow foundation will be dug. The cleared area will be filled with aggregate and then a temporary surface (e.g. geotextile) placed on top. During construction, oil, fuel and other substances will be stored in a storage area within the compound. The area will also be used as a base for refuelling of equipment. 7.173. Indicative floodplain mapping provided by EA shows that all infrastructure are completely within areas of low risk of fluvial inundation. However, there may be localised surface water flows (particularly during rainfall events) that may need to be diverted around this area. This will be particularly important because oil, fuel and other substances will be stored within the building temporary construction compound. Drainage management including the control of runoff in this area will be included in the CEMP. Surface water flows in the area will be further managed by the use of crushed and compacted granular stone in the foundations. This will allow water to infiltrate the foundations, thereby reducing peak surface water flows from the area.

7.12.5 Electric Cabling 7.174. There is potential for cable trenches to transport turbid water from works areas to drainage channels and surface watercourses down gradient. To prevent this, where possible, trenches will be dug during dry weather. This will reduce the likelihood of any excavated material being

CPL PAGE 7-43

Rooley Moor Wind Farm Environmental Statement

mobilised in the trenches. Sand will be placed in the trenches, with the cables placed over the top. To prevent water tracking along trenches, clay plugs or appropriate plugging material will be used in short (typically 1m) sections, with the distance between plugs dependent on the track slope. 7.175. Excavated material will then be replaced as quickly as possible to reduce the period of time that trenches are open. While the trenches are open, impermeable barriers (made of clay or other impermeable material) will be placed at intervals along the open length of the trench. This will reduce the likelihood of trenches becoming preferential flow paths and their capacity to transport turbid runoff to downstream

7.12.6 Borrow Pits 7.176. A system of drainage ditches or temporary interception bunds will be constructed to intercept any surface run off from entering the borrow pit areas. Intercepted surface water runoff will be diverted away to open ground and allowed to discharge. No intercepted/dewatered water will be allowed to discharge directly to surface watercourses. 7.177. Consideration will be given to the stability of surface soils where collected surface water/groundwater is diverted and water collected within borrow pit areas would be treated in the same way. Furthermore, consideration will be given to ensure that water is not discharged to ground directly up gradient or within the sub-catchment of sensitive PWS. 7.178. Where necessary, surface water and groundwater will be passed through temporary settlement or silt traps before being discharged to ground (e.g. silt busters or settlement tanks). All interception bunds and drainage ditches will be fully reinstated once extraction from the borrow pits is completed. Water entering the borrow pits will need to be removed by either gravity drainage design or pumping depending on the overall morphology of the pit. The general topography in the areas identified is conducive to gravity drainage owing to the moderate to steep slopes. All discharges of groundwater will follow advice set out in PPG 6: Working at Construction and Demolition sites. If, following detailed design, dewatering of any of the borrow pits is considered necessary, all dewatering would be designed in accordance with CIRIA guidance C532 entitled “Control of Water Pollution from Construction Sites (2001)” 7.179. It is not anticipated that there will be widespread groundwater present when the borrow pits are being excavated due to the elevation of the proposed structures relative to local springs. Any collection and discharge of groundwater would be dealt with in a similar way to surface water; being passed through a settlement trap before being discharged to ground. Prior to excavation of the rock all surface soils and peat will be removed and stockpiled for use in the reinstatement of the borrow pits. The stockpiles will be located and battered so as to limit instability and erosion. Silt fences and mats will be used to minimise sediment levels in runoff from the stockpiles. 7.180. Following detailed design of the dewatering operations for any given borrow pit, the EA and the local council will be consulted to confirm the environmental acceptability of any dewatering proposals to be provided in the CEMP. 7.181. Prior to any construction or extraction taking place all details relating to the borrow pit will be detailed in the CEMP that will be circulated to the EA and the local authorities for approval before works can commence. This plan will detail how the Development would be constructed and all the necessary mitigation measure to be put in place to mitigate environmental impacts. This would include the general approach to the works and also site specific actions to deal with highlighted risks. In addition this plan will document all environmental monitoring works and emergency response procedures. This plan would typically include information such as:  An emergency response plan with key contact list for emergency services and emergency procedures clearly defined;  A site drainage plan;  A site chemical product and waste inventory;

CPL PAGE 7-44

Rooley Moor Wind Farm Environmental Statement

 A site waste management plan;  A protocol of environmental monitoring procedures and employment of suitable qualified environmental staff; and  Details on compliance with PPGs and CIRIA guidance and any imposed planning conditions. 7.182. Measures to the disturbance and degradation of peat resources during and after the construction of borrow pits will be detailed in the PMP (Appendix 7.2). Borrow pit design, including design of the restoration, will take account restoration objectives relating to habitat and environment. In particular they will be designed such that water levels within the restored habitat can be maintained at ground level, to allow water-logged conditions to be maintained. This can be achieved by excavating the borrow pits downslope where possible, allowing the downslope worked face to retain high water levels within the restored area thus preventing reinstated peat from drying out.

7.13 Residual Effects

7.183. Potentially significant impacts prior to mitigation (either moderate or high) (as described in Section 7.10) have been carried forward for the assessment of residual effects. Those impacts of minor or negligible significance have not been taken forward to this stage. Likely potential significant impacts (prior to mitigation) during construction are limited to only moderate impacts to surface water and geology. During operation, likely potential significant impacts (prior to mitigation) are limited to minor impacts on surface water, which are not considered to be significant and therefore have not been brought forward to this section.

7.13.1 Construction Surface Water

7.184. Likely significant potential effects prior to mitigation that were taken forward for the assessment of residual effects to surface water include the following moderate effects:  A temporary decrease in water quality from the generation of turbid runoff migrating to down gradient surface watercourses, downstream public water supply reservoirs and PWS which may receive surface water runoff from the construction of site infrastructure;  Disturbance to stream banks causing changes in erosion rates and local morphology from the construction of watercourse crossings; and  A decrease in water quality of watercourses located down gradient of a peat slide occurrence. 7.185. Following the implementation of mitigation measures, the likelihood of potential effects has been reduced from moderate to minor and therefore no residual significant effects remain to surface water during construction. Geology

7.186. Likely significant potential effects prior to mitigation that were taken forward for the assessment of residual effects to geology include moderate effects to peat including:  The disruption to peat hydrology and consequent degradation of peat down gradient of access tracks;  The disruption of peat hydrology and the draining of peat due to the dewatering of groundwater during the construction of turbines and borrow pits; and  The disturbance and degradation of peat due to excavation of peat for the construction of site infrastructure.

CPL PAGE 7-45

Rooley Moor Wind Farm Environmental Statement

7.187. Following the implementation of mitigation measures, the likelihood of potential effects has been reduced from moderate to minor and therefore no residual significant effects remain to geology during construction. Groundwater

7.188. There are no likely significant potential effects taken forward for the assessment of residual effects and therefore no residual effects to groundwater remain.

7.13.2 Operation Surface Water

7.189. Prior to mitigation, there are potential moderate impacts to surface water from the vehicular use of tracks and site activities during operation. After mitigation, the likelihood of potential impacts occurring is reduced to possible and only minor residual effects are expected. Groundwater and Geology

7.190. There are no significant negative potential impacts to groundwater or geology expected during operation. Ecological enhancement and peatland restoration measures set out within the HMP (Chapter 8: Ecology) and the restoration of the borrow pit areas are anticipated to result in a moderate positive effect over time as ecology re-establishes.

7.13.3 Decommissioning Surface Water

7.191. Likely significant potential effects prior to mitigation that were taken forward for the assessment of residual effects to surface water include moderate effects limited to a temporary decrease in water quality from the generation of turbid runoff migrating to down gradient surface watercourses and associated receptors from the removal of site infrastructure. 7.192. Following the implementation of mitigation measures, the likelihood of potential effects has been reduced from moderate to minor and therefore no residual significant effects remain to surface water during decommissioning. Groundwater and Geology

7.193. There were no significant negative potential effects to groundwater and geology taken forward for the assessment of residual effects and therefore no residual effects to groundwater or geology remain during decommissioning. Restoration measures set out within the HMP should continue to enhance the ecological environment including peatland habitat throughout and beyond the decommissioning phase.

7.14 Cumulative Impacts

7.194. The potential for cumulative effects relates to proposed or existing developments which are either hydraulically connected to the Development Area, or which drain to the same receiving environment. Potentially significant cumulative hydrological, hydrogeological or geological impacts are usually only likely if wind farms are to be constructed/decommissioned at the same time as the majority of potentially significant impacts occur during construction/decommissioning phase. 7.195. There are 42 wind farm sites either under construction or at the planning stages within 35km of Rooley Moor. Of these, 18 wind farms are located in surface water catchments which drain to the same surface water receptors as Rooley Moor. These are shown in Table 7.14 below.

CPL PAGE 7-46

Rooley Moor Wind Farm Environmental Statement

Table 7.13 Wind Farms within same receiving surface water catchments

Wind Farm Name Status No. of Turbines Catchment Reaps Moss Construction 3 River Irwell Crook Hill Construction 12 River Spodden Todmorden Moor Construction 5 River Irwell Scout Moor Operational 26 Naden and Greenbooth Reservoir, River Roch and River Irwell Scar End Farm Consented 4 River Irwell Sillinghurst Farm Consented 1 River Irwell Veterans Farm Consented 1 River Roch Stand Lees Farm Consented 1 River Roch Bottomly Bank Farm Consented 2 River Irwell Height Side Farm Consented 1 River Irwell Parrock Farm Consented 1 River Irwell Crown Farm Consented 1 River Irwell Gorpley Planning 4 River Irwell Beet Farm Planning 1 River Roch Under Brow Farm Planning 1 River Irwell Wallsclough Planning 1 River Irwell Scout Moor infill Scoping 6 Naden and Greenbooth Reservoir, River Roch and River Irwell Scout Moor Northern Scoping 16 Naden and Greenbooth Extension Reservoir, River Roch and River Irwell

7.196. The magnitude of impact is likely to be highest in catchments where wind farms are in close proximity. Scout Moor, Scout Moor infill and Scout Moor Northern wind farms are located within 5km of the Rooley Moor Wind Farm site, however, Scout Moor is operational and Scout Moor Infill and Scout Moor Northern are only at scoping stages. It is highly likely construction will not have started on these sites by the time the Rooley Moor construction phase ends, thus removing the risk of significant cumulative impacts in the Naden and Greenbooth public water supply reservoirs, Rivers Irwell and Roch. 7.197. The Todmorden, Reaps Moss and Crook Hill wind farms are all under construction. These wind farms are located over 5km from the proposed Rooley Moor Wind Farm. As these wind farms are under construction already, it is considered unlikely that there wold be any overlap in the construction phase with Rooley Moot, resulting in no significant cumulative impacts. 7.198. The majority of the consented wind farms are single turbine developments on farms. Due to the size of these developments and the relatively minor disruption they will cause, impacts to the water and geological environments from these wind farms are likely to be negligible. Furthermore, the

CPL PAGE 7-47

Rooley Moor Wind Farm Environmental Statement

small scale of the developments means construction will likely be completed by the time Rooley Moor construction phase commences. 7.199. Two slightly larger wind farms, Gorpley and Scar End Wind Farm are in planning or have been consented. The Hydrology, Hydrogeology and Geology EIA chapter for Gorpley and Scar End Farm Wind farm have been reviewed. In both cases, no significant residual impacts were expected following the implementation of appropriate mitigation. Both wind farms are within the River Irwell catchment, however they are in separate subcatchments to the Rooley Moor Wind Farm and situated over 5km from the Development Area. Due to distance of these sites from the Development Area, the cumulative effects and resultant significance of impact on the hydrological environment is not anticipated to be significant.

7.15 Summary and Conclusions

7.200. Overall the residual effects of the Proposed Development on the hydrological, hydrogeological and geological environments following the implementation of avoidance and mitigation measures are considered to be minor or less than minor. Residual impacts are limited to:  A temporary decrease in surface water quality during construction and to a lesser extent, during decommissioning from the generation of turbid runoff migrating to down gradient surface watercourses;  A temporary decrease in surface water quality during construction in the event of a peat slide causing peat to migrate to down gradient into surface watercourses;  Disturbance to stream banks causing changes in erosion rates and local morphology during the construction and potential removal of watercourse crossings; and  Disturbance, degradation and draining of peat during construction. 7.201. With the adoption of a comprehensive CEMP, the incorporation of standard good practice techniques and with the avoidance measures already taken into account in the design of the Development, the potential changes to surface water, groundwater and geological environments are not predicted to be significant. 7.202. There is potential for cumulative effects to down gradient surface watercourses during construction if the construction periods of the Scout Moor Infill and Scout Moor North projects coincide. As these EIAs have yet to be written an assessment of cumulative impacts is not yet possible, however, it is likely these wind farms will need to adopt similarly stringent mitigation measures to ensure no significant impacts occur, resulting in no significant cumulative impacts.

7.16 References

7-1 Institute of Environmental Management and Assessment (IEMA) guidance (2004)

CPL PAGE 7-48