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26 Skipton Flood Alleviation Scheme Environmental Statement

27 We are the Environment Agency. We protect and improve the environment and make it a better place for people and wildlife. We operate at the place where environmental change has its greatest impact on people s lives. We reduce the risks to people and properties from flooding; make sure there is enough water for people and wildlife; protect and improve air, land and water quality and apply the environmental standards within which industry can operate. Acting to reduce climate change and helping people and wildlife adapt to its consequences are at the heart of all that we do. We cannot do this alone. We work closely with a wide range of partners including government, business, local authorities, other agencies, civil society groups and the communities we serve. Published by: Environment Agency Horizon house, Deanery Road Bristol BS1 5AH enquiries@environmentagency.gov.uk Environment Agency 2011 All rights reserved. This document may be reproduced with prior permission of the Environment Agency. Further copies of this report are available from our publications catalogue: or our National Customer Contact Centre: T: enquiries@environmentagency.gov.uk.

28 Contents 1 Introduction 1 2 Project development 5 3 Description of the Scheme 8 4 Key issues and methodology 26 5 Human beings and Land Use 31 6 Flora and Fauna 40 7 Landscape and Visual Amenity 69 8 Water quality and hydrology 85 9 Cultural Heritage, Archaeology and Material Assets Traffic and Transport Soils, Geology and Hydrogeology Cumulative Effects Summary of Effects Glossary and Abbreviations 150 Skipton Flood Alleviation Scheme iii

29 Skipton Flood Alleviation Scheme iv

30 1 Introduction 1.1 Introduction The Skipton Flood Alleviation Scheme (FAS) consists of three separate elements: Construction of a flood storage reservoir on Eller Beck upstream and to the north of the A65; Construction of a flood storage reservoir on Waller Hill Beck to the east of Skipton (immediately north of A6069 Otley Road) and excavation of a borrowpit for construction material; and Installation of flood walls at various locations within the town. A single Environmental Statement has been prepared for all three elements of the site. A detailed description of each element has been included in Section 3. The three elements of the scheme fall into different local planning authorities; this means separate planning applications are required, with this ES providing the context for all the applications. The applications include: A planning application for the flood storage reservoir at Waller Hill Beck and for the flood walls in the town centre will be submitted to Craven District Council. An identical joint application will be submitted for the Eller Beck flood storage reservoir to Yorkshire Dales National Park Authority and North Yorkshire County Council. The red line for this element of the scheme covers Craven District Council and Yorkshire Dales National Park Authority. However the Town and Country Planning Act 1990, Schedule 1: Local Planning Authorities: Distribution of Functions (i) states that the carrying out of operations in, on, over or under land, or any use of land, which is situated partly in and partly outside a National Park is a County Matter. This means the planning application must be jointly submitted to Yorkshire Dales NPA and North Yorkshire County Council. A Mineral Planning Application to North Yorkshire County Council, as the mineral authority to construct a borrow pit adjacent to the Waller Hill Beck dam. The borrow pit will provide earth and clay for construction of the flood storage areas. An Environmental Impact Assessment (EIA) is required because the proposed scheme falls above the development thresholds set out in the EIA regulations 1 for flood relief schemes. In addition to the planning applications described above we will also have to obtain an impoundment licence for the construction of the two dams. In addition we will also obtain land drainage consents for all of the works, with the exception of the borrowpit where it is not required. 1 Specifically the scheme falls with 10 (h) of Schedule 2 of the regulations. Skipton Flood Alleviation Scheme 1

31 1.2 The problem The town of Skipton has experienced a number of flood events in recent history, with significant events in 1908, 1979, 1982 and Table 1 below summarises these events. Table 1: Historic flooding in Skipton. Event Date Damages Comment June 1908 June 1979 June Towpath wall collapsed between Eller Beck and Springs Branch. - Total property damage not known - 1 fatality - Widespread flooding on Waller Hill and Eller Becks - Over 50 properties flooded - Flood depths up to 1.2m - Significant property damage at Shortbank Road - Flow torrent down Shortbank Road, road surface ripped up - Torrential storm on Rylestone Fell rain in <1 hour - 66mm rain fell in 24 hours - Culverts blocked by debris caused overtopping (particularly Waller Hill Beck) - Significant overland flow as drains and watercourses blocked - Intense summer rainstorm over high ground to south of Skipton June properties flooded at Back Bridge Street - Water backed up from Morrisons and Broughton Rd culverts October Homes flooded at Back Bridge St - Morrisons supermarket and Focus DIY flooded - Ings Lane Industrial Estate flooded - Riverside wall collapsed at Back Bridge St Currently there are 230 residential and 90 commercial properties at risk of flooding during a 1 in 100 year event. Such an event could cause over 15,000,000 of damages. The potential extent of such a flood event is illustrated in the figure below. Skipton Flood Alleviation Scheme 2

32 Figure 1. Existing flood map for Skipton in a 1 in 100 year flood event (figure not to scale). The FAS is designed to provide homes and properties within Skipton with protection from a flood event with a likelihood of occurring of 1 in 100 years (or a 1% annual chance of occurrence) including an allowance for climate change. 1.3 Environmental Impact Assessment The proposed development is not of a type described in Schedule 1, however the proposed development would be classified as EIA development under Schedule 2; 10(h). The EIA and this Environmental Statement (ES) has been undertaken under the provisions of Part 2; 4(2) of the Regulations and, accordingly, we have sought a formal screening opinion from the Yorkshire Dales National Park and this confirmed that an EIA was required. 1.4 Structure of the report The remainder of this ES is structured as follows: Chapter 2. Description of the background and context for the project, the alternative options that were considered and discounted and a description of the preferred option on which the EIA is based; Chapter 3. Detailed description of the scheme including durations, physical parameters, resource use, pollution prevention measures and construction methodology; Skipton Flood Alleviation Scheme 3

33 Chapter 4. Description of the EIA methodology, a summary of the issues that have been scoped out of and into the assessment and the strategic context for the project; Chapters 5 to 11. EIA technical assessment chapters consisting of Human Beings and Use, Flora and Fauna, Landscape and Visual Amenity, Water Quality and Hydrology, Cultural Heritage and Archaeology, Traffic and Transport and Soils, Geology and Hydrogeology. Chapter 12. Provides an assessment of the cumulative effects; and Chapter 13 Provides a summary of the likely significant effects from the Skiption FAS. Due to the fact there are three separate planning applications for different elements of the FAS each technical chapter (5 to 11) has separated the environmental impacts of each of three sites and the borrow pits: Eller Beck Flood Storage Area; Waller Hill Beck Flood Storage Area; Waller Hill Beck Borrow Pit; and Town Centre flood walls. Skipton Flood Alleviation Scheme 4

34 2 Project development 2.1 Nature and background to the project Following the flooding in Skipton in 2000 we have reviewed the risks from flooding along with the current levels of flood protection that properties within the town currently benefit from. This highlighted that there are sufficient economic benefits from undertaking works to create new flood defences for Skipton. The rest of this chapter sets out the strategic context for the scheme, the alternative options that were considered and discounted and the reasons for taking forward this scheme as the preferred option. 2.2 Strategic Context for the Scheme Skipton is within the Environment Agency s Upper Aire Flood Risk Management Strategy. The Strategy recommends investigating flood management measures on Eller Beck, Waller Hill Beck and Ings Beck in order to protect Skipton from river flooding (sometimes referred to as fluvial flooding). 2.3 Alternative Options A wide range of options have been considered for the Skipton scheme, and evaluated based on environmental impact, cost and technical feasibility. Following an initial evaluation of all the potential options a shortlist was created. The table below compares the environmental effects of the shortlisted options which were under consideration. Table 2. Comparison of alternative options. Proposed Scheme Positive Environment Effects Negative Environmental Effects Upstream storage on Eller Beck and Waller Hill Beck and localised construction of walls or raising the height of existing walls through Skipton town centre. Control river / canal interaction with localised wall raising and downstream washland creation at Sandylands playing fields. Widespread defence raising (walls), in Potential for habitat creation associated with the creation of the storage areas. Reduction of flood risk to properties in Skipton. Minimises the extent of visual impacts within Skipton by avoiding the construction of large and high walls. Washland creation benefits for biodiversity and an opportunity to contribute towards WFD mitigation measures. Washland creation benefits for biodiversity and an opportunity Construction impacts on local landscape, potential impacts on biodiversity and increasing the length of culverted watercourse. Localised visual impacts. Potential traffic impacts if materials for the construction of upstream reservoirs have to be brought to site by road (rather than sourced from local borrow pits). Impacts of wall raising on conservation area, visual amenity, recreation and the visitor economy by cutting off access to the watercourses within Skipton town centre. Potential traffic impacts if materials for works to the downstream washland have to be brought to site by road (rather than sourced from local borrow pits). Impacts of wall raising on conservation area, visual amenity, recreation and the visitor economy by cutting Skipton Flood Alleviation Scheme 5

35 Proposed Scheme addition to downstream washland creation. Positive Environment Effects to contribute towards WFD mitigation measures. Negative Environmental Effects off access to the watercourses within Skipton town centre. Potential traffic impacts if materials for works to the downstream washland have to be brought to site by road (rather than sourced from local borrow pits). The magnitude of these impacts would be greater than those described above. Following flood modelling, economic appraisal and consideration of the environmental impacts of the various options, it was concluded that the preferred option is upstream storage on both Eller Beck and Waller Hill Beck, in combination with raised defences in the town centre. This combination of scheme elements was preferred because a scheme that only consisted of walls would be technically challenging to construct given the limited access to the watercourses; the proximity of residential and commercial properties in the area of the works and size of the resulting defences. Furthemore the size of the defences would limit connectivity with the water courses in Skipton Town Centre and potentially result in significant effects on townscape, heritage and human beings. During the design of the preferred option further specific design alternatives were considered. This was particularly concerned with the way that the Eller Beck dam structure operated. Two options were considered: One that operated passively and would not need any intervention (e.g. does not require any human intervention such as closure of a penstock to restrict the quantity of water flowing through culvert that passes through dam); and One that operates semi-passively (i.e. does not require human intervention to operate but uses electronic sensors to close a penstock to restrict the amount of water passing through the dam and into the centre of Skipton during a flood event). Of these two options the semi-passive option has been selected because the passive option would restrict fish passage through the dam and would not comply with the requirements of the European Water Framework Directive (WFD). The semi-passive option allows the penstock to be open during periods of normal flow and will not restrict fish passage and as complies with the requirements of the WFD. 2.4 The preferred option The preferred option consists of the following components: Eller Beck Flood Storage Reservoir. This structure will run across the river valley from the A65 road embankment to high ground next to the mineral railway; Waller Hill Beck - Flood Storage Reservoir. This will run across the river valley from the edge of the A6069 to high ground on the opposite side of the beck; Waller Hill Beck Borrowpit. This will be located within the vicinity of the Waller Hill Beck dam works and will be used to provide material to construct both Waller Hill and Eller Beck dams. Eller Beck Spindle Mill. The existing wall along the right bank will be raised by 0.8m over a 30m length to tie into the culvert that runs under Coach Street. The raised section will be clad in stone to match the existing wall; Skipton Flood Alleviation Scheme 6

36 Eller Beck - Morrisons and Discount Store. A new flood wall will be constructed around the open section of Eller Beck between Broughton Road and the culvert under the supermarket car park. The wall will be 0.4m high on the left bank and 0.75m high on the right bank. The new wall will be clad in a material that is in-keeping with nearby buildings; and Waller Hill Beck Ginnel Mews and Devonshire Place. The existing riverside wall along the right bank will be raised by 0.5m to an overall height of 1.5m. The raised section will be clad to match the existing wall. Downstream of Ginnel Mews, at Devonshire Place a wall will be built. Skipton Flood Alleviation Scheme 7

37 3 Description of the Scheme 3.1 Introduction The general location of the different elements of the FAS can be found in Figure 2. Figure 2. General location of the different scheme elements. 3.2 Eller Beck Flood Storage Reservoir Overview Flood flows above 17m³/s shall be restricted by a flow control structure and flood waters shall be stored behind an earth dam at the Eller Beck site. The flood flows will be monitored at Skipton Woods and linked to the flow control structure at the Eller Beck site. Under normal conditions the control structure shall not restrict the flow of Eller Beck. The dam shall contribute to the 1 in 100 year standard of protection in Skipton, in conjunction with the other components of the scheme. Skipton Flood Alleviation Scheme 8

38 In summary, the flood storage reservoir at Eller Beck shall comprise the following elements: The dam with grassed 1v:4h side slopes; Reinforced concrete spillway channel. This shall have a labyrinth weir at the upstream extent and a stilling basin at the downstream extent; Reinforced concrete inlet structure, which houses steel trash screens and a cast iron penstock; Reinforced concrete culvert which passes through the dam and conveys the flow of Eller Beck; Realignment of Eller Beck; New road junction at the A65 to facilitate vehicle access to the dam; Installation of telemetry equipment downstream of the dam (will be included in a separate planning application when the route of the cabling is known); and Landscaping, including an area safeguarded for future use by the golf course.. Prior to the commencement of construction, site clearance works shall be required. This includes the felling of trees and the temporary relocation of golf course infrastructure. The works will take approximately 22 months to complete from summer 2014 to spring 2016 (with a break of approximately 4-5months to avoid adverse winter weather conditions). For a detailed plan illustrating the general arrangement see Appendix B (drawing number EB_103General Arrangement Plan). Figure 3. View of the existing golf course area (looking north). Skipton Flood Alleviation Scheme 9

39 Figure 4. General overview of proposed works at Eller Beck (not to scale). Debris screen, penstock and entrance to culvert Site access track Reinforced concrete spillway Location of photograph Figure 3 Culvert Grass covered earth dam Dam and spillway The dam stretches across the width of the valley at the southern extent of the golf course. The left abutment ties in to an area of land currently used as grazing by the land tenant. It is adjacent to a train line. The right abutment ties in to an area currently used as a practice range of the golf course. It is adjacent to the A65 road embankment. At the bottom of the valley the dam shall be approximately 14m high. The dam crest has been set by providing an allowance for wave run-up above the peak water level generated by a Probable Maximum Flood (PMF). Key information of the dam is provided in the table below: Crest (top) level (maod) Height of dam. Spillway weir at (top of weir 143.4m AOD (including an allowance for postconstruction settlement). This equates to approximately 14 metre above existing ground levels. Crest width (m) 4 Approximate length of dam (m) 325 Upstream slope (and material) Downstream slope (and material) 1v:4h (grass) 1v:4h (grass) Skipton Flood Alleviation Scheme 10

40 Approximate volume of material in dam (m³) 95,000 Approximate volume of water storage at spillway level (m³) 433, Spillway The spillway shall comprise three elements: a labyrinth weir at the upstream extent, a channel and a stilling basin. A labyrinth weir is a weir that has been folded in plan to reduce the width of the structure. At Eller Beck, the total length of weir is 51.5m but the structure is 31.8m wide. The weir shall be formed with reinforced concrete and shall be 2m high, with reinforced concrete walls upstream of the weir to retain the dam and the valley side. Immediately downstream of the weir, the water shall be conveyed through a 31.8m wide reinforced concrete channel. This shall taper to a width of 29.86m. The maximum depth of the channel below ground shall be 2m. There will be no concrete above ground. The top of the side walls of the channel will finish flush to the ground and a timber post and rail fence installed to prevent trips or falls into the spillway. The stilling basin is located at the downstream extent of the channel and shall dissipate the energy of the water in the spillway. This structure shall be constructed using reinforced concrete and shall be 29.86m wide. Baffle blocks shall be required to facilitate the dissipation of energy. Under normal flow conditions the spillway and stilling basin shall not be in operation Control structure The structure that controls the flow downstream shall comprise an inlet structure and culvert. The inlet structure shall comprise a reinforced concrete headwall with reinforced concrete wing walls. The headwall shall house an on-seated penstock which shall restrict flows greater than 17m³/s from passing downstream. Flood flows above 17m³/s shall be restricted by a flow control structure and flood waters shall be stored behind an earth dam at the Eller Beck site. The flood flows will be monitored at Skipton Woods and linked to the flow control structure at the Eller Beck site. The penstock shall remain fully open during normal conditions to prevent premature flooding of the golf course and allow light to penetrate the entrance of the culvert to facilitate fish passage. The penstock shall be controlled by flow monitoring equipment positioned downstream of the A65 road embankment. There shall be a kiosk at the right abutment crest which allows further control of the penstock. Galvanised steel trash screens (painted black) and working platforms shall be installed within the inlet structure to prevent catchment debris from damaging the penstock equipment or blocking the culvert. Vehicular access shall be provided from the A65 to the inlet structure via a berm on the upstream face of the dam. The culvert shall be reinforced concrete. The cross sectional dimensions shall be 2.5m wide by 2.3m high. The culvert shall be 91m in length. The invert of the culvert shall contain 0.3m high baffles which shall help retain geomorphological materials and create a low flow channel to facilitate fish passage. Skipton Flood Alleviation Scheme 11

41 3.2.5 Channel diversion Eller Beck shall be diverted to pass through the control structure. The gradient of the diversion shall conform to the gradient of the watercourse as a whole. The cross-sectional shape of the channel shall allow geomorphological features to be incorporated in the design. Backwaters shall be provided upstream and downstream of the dam. The section of channel downstream of the dam shall be engineered to prevent erosion during high flows Road junction A new road junction shall be provided on the A65 to allow Environment Agency maintenance vehicles access the dam. The road junction shall be located adjacent to the right abutment. Vehicular access shall be provided to the inlet structure via a berm along the upstream face of the dam. All access routes shall be surfaced to be in keeping with the local landscape Telemetry A new road junction shall be provided on the A65 to allow Environment Agency maintenance vehicles access the dam. The road junction shall be located adjacent to the right abutment. Vehicular access shall be provided to the inlet structure via a berm along the upstream face of the dam. All access routes shall be surfaced to be in keeping with the local landscape Landscaping The site shall be landscaped in keeping with the local environment. The use of dry stone walls to screen the concrete spillway and extensive planting is proposed. Further information on the landscaping proposal can be found in the Design and Access Statement and Landscape Plan The part of the fairway and the green of the 16th hole and the tees and green of the 17th hole shall be affected by the works. An area of land has been safeguarded for future golf course use. The exact design of the new tees is currently being developed by Skipton Golf Course. The existing footbridges that cross Eller Beck in the golf course shall be replaced where necessary so that they withstand flood events. Further landscaping and replanting shall be discussed in subsequent chapters of this Environmental Statement Site access and compound During construction, site access shall be from the A65 via the new road junction. The main site compound shall be located at the Waller Hill site. However a smaller satellite compound shall be located within the red line boundary of the Eller Beck site. 3.3 Waller Hill Flood Storage Reservoir Overview The proposed scheme on Waller Hill Beck is located to the east of Skipton Town centre. The dam is located across Waller Hill Beck, to the north of the A6069, Otley Road and south of the A65. The dam is sited in pastureland, and within the lower section of the valley. Skipton Flood Alleviation Scheme 12

42 Approximately 100m downstream of the dam location, the valley narrows. Upstream the valley is typically grazed grassland. Figure 5. View of the general location for the Waller Hill Flood Storage Reservoir from the south of the reservoir looking north. Figure 6. General overview of proposed works compound, borrowpit and embankment at Waller Hill Beck (not to scale). Site compound Indicative location of Borrowpit See Temporary Storage area Dam Location of photograph Figure 5 In summary, the flood storage reservoir at Waller Hill Beck shall comprise the following elements: The earth dam with grassed 1v:4h slope & upstream slope 1v:4h; Reinforced grass spillway channel on the downstream face, which terminates in a reinforced concrete stilling basin and tumblebay; Reinforced concrete inlet structure, which houses steel trash screens and steel orifice plate; Skipton Flood Alleviation Scheme 13

43 Reinforced concrete culvert which passes through the dam and conveys the flow of Waller Hill Beck: New construction access from the A65 and permanent maintenance access from the A6069 Otley Road ; Creation of BAP habitat, tree planting and landscaping; and Creation of compensatory habitat for the loss of habitat on Eller Beck to comply with the European Water Framework Directive and habitat creation. Prior to the commencement of construction, site clearance works shall be required. The works will take approximately 9 months to complete from summer 2014 to spring The main site compound will also be located adjacent to this area of the scheme. A detailed drawing of the general arrangement of the dam can be found in Appendix B (WH_103_General Arrangement Plan). Figure 7. General overview of proposed flood storage reservoir dam at Waller Hill Beck (not to scale). Grass covered earth dam Concrete Culvert through embankment Grasscrete spillway Access track from A6069 for maintenance General description The Skipton Flood Alleviation Scheme requires the construction of a flood storage reservoir on Waller Hill Beck. Flood flows above 1.7m³/s shall be retained by a flow control structure, and flood waters shall be stored behind the dam. Under normal conditions the control structure shall not restrict the flow of Waller Hill Beck. The dam shall contribute to the 1 in 100 year standard of protection in Skipton, in conjunction with the other components of the scheme. Skipton Flood Alleviation Scheme 14

44 3.3.3 Dam and spillway The dam stretches across the width of the valley, approximately 100m upstream of the ravine. Both the left and right abutments tie in to an area of land currently used as grazing by the landowner. At the bottom of the valley the dam shall be approximately 9.5m high, with the spillway crest set at the 1 in 100 year flood water level. Key information of the embankment is provided in the table below: Crest (top) level (maod) Spillway at Height of dam 149.6m AOD (including an allowance for postconstruction settlement). This equates to approximately 9.5 metres above existing ground levels. Abutments at Crest width (m) (and material) Spillway at 11.0 (reinforced grass) Abutments at 4.0 (grass) Approximate length of dam (m) 105 Upstream slope (and material) 1v:4h (grass) Downstream slope (and material) 1v:4h (reinforced grass on spillway, grass on abutments) Approximate volume of material (m³) 20,000 Water storage at spillway level (m³) 162,325 The spillway shall comprise a reinforced grass open channel cut in to the downstream face. The reinforcement shall be open cell concrete blocks, hidden from view by topsoil and grass. The spillway channel shall terminate in a stilling basin Stilling basin The stilling basin is formed as a reinforced concrete pool, which has raised concrete blocks to help dissipate the energy from the water. A low flow channel will be incorporated to take the normal river flows Control structure The structure that controls the flows downstream shall comprise an inlet structure and culvert. The inlet structure shall comprise a reinforced concrete headwall with reinforced concrete wing walls. Galvanised steel trash screens and working platforms shall be installed within the inlet structure to prevent catchment debris from blocking the culvert. Vehicular access shall be provided from the A6069 to the inlet and outlet structures. The culvert shall be reinforced concrete and of size 1.2m by 2.0m high. The cross sectional dimensions of the orifice plate shall be 0.4m wide by 0.4m high. The culvert shall be 66m in length. The invert of the culvert shall contain 0.3m high baffles which shall help retain geomorphological materials and create a natural bed. Therefore the internal height of the culvert shall be 1.7m (i.e. the height from the top of the baffles on the base of the channel to the roof of the culvert. The culvert shall convey the flows of Waller Hill Beck and discharge in to the stilling basin. From there the beck flows back into the existing natural channel Channel diversion Waller Hill Beck control structure will be constructed on line. This means that the existing channel will not require diverting. Skipton Flood Alleviation Scheme 15

45 3.3.7 Road junction A temporary site access will be created using an existing access off the A65. This junction will be improved to allow construction access. A new site access shall be provided on the A6069 to allow Environment Agency maintenance vehicles access the dam. The road junction shall be located downstream of the left abutment. Vehicular access shall be provided to the inlet structure. All access routes shall be surfaced to be in keeping with the local landscape Landscaping and habitat creation The dam and reinforced grass spillway will be finished as grassed surfaces in keeping with the existing area. The scheme also includes tree planting and the creation of BAP habitat. As part of the proposed works at Waller Hill Beck, the creation of BAP habitat and improvement of the existing watercourse is proposed. At the downstream end of the proposed dam, 250m of river will be restored to create a meandering plan form increasing the channel length and reducing the gradient of the channel. The new channel will have varying cross-section profiles through its length and in-channel features to create flow diversity and ultimately improve the biodiversity. Within this downstream area backwater reed habitat/pond areas will also be created with side channels off the main channel, totalling 0.2ha of BAP habitat. Upstream of the proposed dam, approximately 500m of watercourse will be meandered to improve flow diversity and arrangement to encourage overspill onto adjacent land for the creation of 1.8ha of BAP habitat in the form of floodplain grazing marsh, reed beds and wet woodland. These works will require excavation of existing ground to reach desired levels for the creation of the required habitat types. 3.4 Waller Hill Borrow Pit A borrowpit covering a maximum area of approximately 6.8 ha and excavated to a maximum depth of 2-3 m below ground level will be excavated. The slopes are 1 in 5 on the north, east and west and horizontal on the southern side. The maximum amount of material that could be extracted from the borrowpit is 158,000m 3. This is in excess of the amount required to build both Eller Beck and Waller Hill Beck Dams. However, there is a degree of uncertainty about whether all of the material will meet the technical requirements for the construction of the dam. If there is a short fall of material it will be imported to site by road from another location. To reduce the visual intrusion of the borrowpit the edge of pit is curved (as illustrated in Figure 8). The material will be excavated so that the remaining surface is similar to the topography of the landscape before the material was excavated. If suitable, material excavated Skipton Flood Alleviation Scheme 16

46 from the construction of the two dams will be used to re-contour the borrowpit. It will also be reseeded to allow it to return to grazing once the works are complete. Figure 8. Waller Hill Borrow Pit (not to scale). 3.5 Town Centre Works The Town Centre works consists of four areas of flood walls. These works are described in more detail below. The town centre works will take approximately 6 months to complete from autumn 2014 to spring Morrisons Open Channel, Eller Beck Layout Reinforced flood defence walls are required on both left and right banks of Eller Beck at Morrisons open culvert Skipton Flood Alleviation Scheme 17

47 Left Bank: The flood defence wall will be constructed along the existing wall line at the store car park. The wall will tie in from the Broughton Road bridge parapet wall to the Morrisons culvert headwall downstream over an approximate length of 46m. A safety hand rail will be required to be installed on top of the raised flood wall for health and safety purposes. The height of the new wall be approximately 0.60m above ground level. Both sides of the wall will be clad with stone. Right Bank: A reinforced concrete flood wall will be constructed along the existing fence line. The wall will tie from the Broughton Road bridge parapet wall to the Morrisons culvert headwall downstream over an approximate length of 29m. Pointed coping will be placed on top of the wall for health and safety purposes. The new wall will be built to maximum height of 1.3m above ground level. Both sides of the wall will be clad with stone. Figure 9. View of the general location for the works next to Morrisons car park looking south west). Figure 10.Proposed works at Morrison s supermarket (not to scale). A6069 Broughton Road Eller Beck New flood wall Skipton Flood Alleviation Scheme 18

48 Location of photograph Figure 9 New flood wall Access to Morrisons supermarket Spindle Mill, Eller Beck It is required to raise the existing level of the low wall immediately upstream of Coach Street culvert on the right bank over a length of approximately 15m. The pedestrian access gate immediately downstream of the low railing wall at the back of Spindle Mills will also be required to be raised. (see Appendix B TW_SM_103_Spindle Mill General Arrangement Plan). The wall height will be required to be raised to 0.46m above ground level. The existing access will be raised to approximately 0.21m above ground. Stone is proposed to be used raise the level of wall and access step. Figure 11. View of the general location for the works at Spindle Mill looking north east. Skipton Flood Alleviation Scheme 19

49 Figure 12. Proposed works at Spindle Mill (not to scale). Skipton Flood Alleviation Scheme 20

50 New flood wall Location of photograph Figure Ginnel Mews and Devonshire Place, Waller Hill Beck Ginnel Mews A reinforced concrete flood wall is required upstream of the playground pedestrian bridge on the right bank only. The existing stone wall will be replaced with a reinforced concrete flood wall to flood defence level over a length of approximately 11.5m. The existing level of the wall is 0.90m above ground level. The new flood defences will be a maximum of 1.11m above ground level (see Appendix B TW_GM_103_Ginnel Mews_General Arrangement Plan). The low section of wall will also be raised using a reinforced concrete wall to flood defence level over a length of approximately 14m. The top of the defence flood level will be at a height of 1.09m above ground level. The pedestrian bridge will be raised, with steps and a ramp (1:12gradient) providing access from Ginnel Mews to Devonshire Street and Millennium Walk. The existing pedestrian bridge soffit will be raised by 0.52m. Downstream of the pedestrian bridge, the existing playground boundary wall on the right bank will be replaced by a reinforced concrete wall to flood defence level and will follow the existing line of the wall over a length of approximately 60m. The existing playground boundary wall level varies from 0.60m to 1.01m above ground levels. Maximum flood defence level will be at a wall height of 0.5m above ground. Both reinforced concrete flood walls will re-use existing stone to clad both sides (additional stone will also be required to complete the cladding). Pointed coping stones are to be placed on top of the wall for health and safety purposes. Skipton Flood Alleviation Scheme 21

51 Figure 13. View of the general location for the works at Ginnel Mews looking west. Figure 14. Proposed works at Ginnel Mews (not to scale). New flood wall Ramp Location of Photograph Figure 13 Footbridge Skipton Flood Alleviation Scheme 22

52 Devonshire Place, Waller Hill Beck A reinforced concrete flood defence wall on the right bank is required from the culvert headwall to tie into the boundary wall located in front of the government buildings (see Figure 16). The new wall will be a maximum height of 1.84m above existing ground levels (although this will be significantly lower along the rest of the works) (see Appendix B TW_DP_103_Devonshire Place General Arrangement Plan). Strengthening works of the culvert headwall and the boundary wall at the government buildings are required to be undertaken. Further upstream, strengthening works to the bowling club boundary wall may also be required. The defence wall is to be finished with cladded stone. The existing bed level is to be retained with natural bed material placed over the wall base. Ground levels at the pedestrian access from Devonshire Place to Ginnel Mews may need to be raised through landscaping. Upstream of the government buildings, raising of the timber arch pedestrian bridge may be required. Figure 15. View of the general location for the works at Devonshire Place looking east. Figure 16. Proposed works at Devonshire Place (not to scale). Skipton Flood Alleviation Scheme 23

53 Works to culvert headwall New reinforced concrete wall Connection to the downstream end of the works at Ginnel Mews Location of Photograph Figure Prevention of Pollution Our contractors are all required to follow good industry practice include our Pollution Prevention Guidance and CIRIA s Good Site Practice Guide. This is particularly relevant where works will require in channel works (e.g. at the two flood storage areas). We will be required to obtain consent to carry out these works and will comply with all relevant environmental permits and legislation regarding pollution prevention. 3.7 Site Welfare and accommodation The main site compound for the construction works will be located at Waller Hill Beck. This is where the site office and main welfare facilities will be located along with equipment and fuel stores. The indicative location of these is shown in Figure 6. Welfare facilities will also be provided for construction staff working at the Eller Beck and Town Centre sites. 3.8 Construction Methodology The construction of the different elements of the scheme are summarised below and are based on the best available information at the time of the assessment; The two dam structures will be constructed out of suitable cohesive soils (from the borrowpit at Waller Hill with additional material imported to site if required). The spillway at Eller Beck is likely to be constructed from re-inforced in situ concrete however the grasscrete spillway at Waller Hill Beck will use precast concrete units. The culverts for each dam will be constructed from concrete, which is likely to use pre-cast units. The debris screens will be attached to the upstream entrance of each culvert; Skipton Flood Alleviation Scheme 24

54 The works to enhance and create habitats along Waller Hill Beck will include excavating and re-profiling the channel to create new geomorphological features. This will be supplemented by planting where required; and The town works will involve excavation works so that foundations can be constructed for the new walls and footbridge. In sensitive locations these walls will be clad using stone. The specific methods of construction will be refined once a contractor has been appointed for the works. 3.9 Decommissioning For the purposes of this ES it has been assumed that if any of the works were to be decommissioned and returned to their pre-construction state the activities would be the reverse of the construction activities assessed in this ES. The only key difference would be the potential generation of wastes (particularly from hard landscape and heavy engineered structures such as the walls, reservoir spillways and culverts). Although decommissioning has the potential to generate wastes it is anticipated that all materials generated during the decommissioning works could be recovered for re-use or recycling. As a consequence it is concluded that decommissioning would not result in any additional impacts not already assessed under the construction part of the assessment. There this is not assessed as separate element in the assessment chapters (5 to 11). Skipton Flood Alleviation Scheme 25

55 4 Key issues and methodology 4.1 EIA Methodology Undertaking an EIA helps to ensure that likely significant environmental effects (both beneficial and adverse) of the Development are assessed in a systematic way. In addition, it enables the importance of these impacts and the scope for reducing or enhancing them, to be clearly understood by the determining authority and its consultees, as well as the general public. The information compiled during the EIA is presented in this ES that accompanies the planning application for the Skipton FAS. The EIA has been conducted in accordance with current Government regulations, policy and good practice. The EIA process consists of the two main stages. 4.2 Scoping The Scoping Report represented the first stage in the EIA process (see Appendix C). Its main purpose was to provide information on the Development, set out the scope and methodology for assessing the likely significant environmental effects for consultation. The responses received from consultees regarding the scope of the EIA can be found in Appendix C and have been incorporated into the scheme and the EIA. The topics that were scoped in and scoped out of the EIA process are listed in the table below. Table 3. Topics scoped in and out of the assessment. Topic Scoped in or out Explanation and response Air Quality Out There are no existing air quality issues or highly sensitive receptors (e.g. an Air Quality management Area) and the proposed scheme is unlikely to generate significant emissions (either during construction and operation). Issues, such as preventing potential fugitive dust emissions will be managed through contract requirements of the construction contractors that will require the implementation of best practice site management measures. Air quality is scoped out for both the construction and operational stages of the scheme. Noise and vibration Out Within the built up areas of Skipton if piling is required for the foundations of flood walls low noise and vibration techniques will be applied (i.e. the use of bored pilings instead of steel sheet piles installed using noisy percussive techniques). This will avoid adverse effects on potentially sensitive nearby receptors (houses on Ginnel Mews and Devonshire Place). Noise and Vibration is scoped out for both the construction and operational stages of the scheme. Human Beings In The construction phase of the works are likely to affect landowners (where the works are taking place) as well as people that live, work and visit the town, the Eller Beck site and the Waller Hill Beck site during construction. Once in operation the dams will have localised effects on land use within each storage area. For these reasons these effects have been assessed in the EIA for both construction and operation. Flora and Fauna In The works will require the removal of mature trees, physical changes to two watercourses and the enhancement of existing habitats. Due to the presence and potential to have a significant effect on these features this topic has been included in the EIA and an Ecological Impact Assessment (EcIA) undertaken. It assesses Skipton Flood Alleviation Scheme 26

56 Topic Landscape and Visual Impacts Water quality, drainage and hydrology Cultural Heritage, Archaeology Traffic and transportation Soils, Geology and Hydrogeology Scoped in or out In In In In In Explanation and response potential effects associated with both the construction and operational stages of the scheme. For these reasons these effects have been assessed in the EIA for both construction and operation. The works include the removal of vegetation and the construction of two new features within the landscape, one of which will lie within the Yorkshire Dales National Park. Furthermore, the centre of Skipton is also a Conservation Area and as such will be sensitive to changes in townscape. Due to the scale and presence of sensitive features and receptors this topic has been included in the EIA and a Landscape and Visual Impact Assessment (LVIA) undertaken. The assessment only considers operational effects not construction because these will be short term and temporary. The works will include in channel construction works and the construction of new sections of river channel (e.g. culverts through each of the dams). As a result it will be necessary to assess the effects of these on downstream river flows. Water quality, and more broadly the ecological status or potential of the waterbodies within the scheme study area will also be considered to ensure that proposals comply with the requirements of the European Water Framework Directive (WFD) and will assess the effects associated with both the construction and operational phases of the scheme. The whole of Skipton town centre is a Conservation Area. However, there are no listed buildings or scheduled monuments in direct proximity to the proposed scheme. As result impacts on setting and context are considered. Although potential effects on designated features are limited this topic has been scoped in due to the potential effects of the scheme on the setting of buildings and features (e.g. bridges) within the conservation area and the potential for below ground archaeological features to be encountered. The construction phase will assess the potential for direct effects on heritage features and their setting. However, once operational the assessment only considers impacts on the setting of heritage assets. An assessment of the likely significant effects from transport impacts has been scoped into the assessment because the works to construct the two flood storage reservoirs are likely to generate considerable numbers of HGV movements (transporting material from the Waller Hill Beck borrowpit to provide material to construct the Eller Beck flood storage reservoir). For these reasons these effects have been assessed in the EIA for construction. However operational movements have been scoped out. This has been scoped into the assessment for construction only because of the scale of earthworks for the flood storage areas, the creation of the borrowpit and the works through the town centre where potentially polluting substance may be encountered during construction. Waste Out Although some waste will be generated during construction this is likely to be limited because it will not involve the generation of large scale quantities of demolition waste. During operation the completed scheme will only generate limited quantities of waste (e.g. the removal of debris from screens or debris catchers (debris is often found in watercourses from either man made or natural sources can foul structures such as culverts which if not removed can increase the risk of flooding. This scoped out for both phases of the scheme. Skipton Flood Alleviation Scheme 27

57 The Scoping Report was issued for public consultation in 2010 and the responses received have been used to inform the preparation of this ES. More widely we have been consulting with the community in general, potentially affected landowners, occupiers and residents, elected district and town councillors and the relevant planning authorities since This consultation has influenced our approach to the construction of the scheme. For example consultation with the Town Council has highlighted the key events in the town where construction works could potential cause significant disruption (e.g. the Tour de France in 2014 and the Waterway Festival). As a result of this consultation we will ensure that our construction activities do not impact on these events by programming works to avoid any potential conflicts. Further details of the consultation activities that have been undertaken during the development of this scheme can be found in the Statement of Community Involvement that accompanies the planning applications. 4.3 Baseline A wide range of baseline data and information sources on the environmental conditions of the area have been used for the purposes of impact assessment. Data has been gathered via: Field survey information, including background noise levels, ecological features, landscape character, and traffic levels on the local road network; Maps of historical and contemporary features; Data from statutory and non-statutory consultees; and Published and unpublished literature. More detailed information is included in each of the topic sections, as required, to describe the aspects of the environment likely to be significantly affected by the proposed development. 4.4 Impact Assessment Predicting impacts and assessing effects The EIA Regulations state that the ES must describe the likely significant effects of the project on the environment, with reference to its possible impact on: human beings, fauna, flora, soil, water, air, climatic factors, material assets (including the architectural and archaeological heritage), landscape and the inter-relationships between the factors. The methodologies for assessment vary from topic to topic. In general however, all of the assessments involve a process of interaction between the designers of the proposed development and the emerging findings of the EIA. The significance of effects has been evaluated with reference to recognised standards and accepted criteria for each assessment topic, where these are available. Where no recognised standards or criteria exist, professional judgement has been used to develop an appropriate approach to undertaking a robust and appropriate assessment. Each environmental topic section in this ES describes the approach that has been taken. In determining whether a resulting effect is significant due consideration has been given to: Magnitude; o Duration (whether short, medium or long term); o Frequency of occurrence; o Nature of the effect (whether direct or indirect, permanent or reversible); o Whether it occurs in isolation, is cumulative or interactive; Skipton Flood Alleviation Scheme 28