GEM BRIDGE ENVIRONMENTAL STATEMENT...Network route in this location. The bridge, to be known as Gem Bridge, would carry the cycle/walkway approximately 24m above the River Walkham

DEVON COUNTY COUNCIL

July 2009

Prepared by Parsons Brinckerhoff Ltd The Forum Barnfield Exeter EX1 1QR

Prepared for Devon County Council County Hall Topsham Road Exeter EX2 3QD

GEM BRIDGE ENVIRONMENTAL STATEMENT Non-Technical Summary

Report Title : Gem Bridge Environmental Statement Non-Technical Summary Report Status : Draft Job No : HPE 91789 Date : July 2009 Prepared by : .......................................................................... Elaine Tyldesley Checked by : .......................................................................... Marcus Wood Approved by : .......................................................................... David Carter

AUTHORISATION SHEET

Client: Project: Address:

PREPARED BY Name: Position: Date:

AGREED BY Name: Position: Date:

AUTHORISED FOR ISSUE Name: Position: Date:

DISTRIBUTION ACCEPTED BY

Name: Position: Date:

ACCEPTED BY Name: Position: Date:

Non-Technical Summary Prepared by Parsons Brinckerhoff Ltd July 2009 for Devon County Council

CONTENTS Page

NON-TECHNICAL SUMMARY 1 1.1 Introduction and Background 3 1.2 Description of the Scheme 4 1.3 Alternatives Considered 5 1.4 Assessing the Impacts 6 1.5 Summary of Environmental Impact Assessment 6

NON-TECHNICAL SUMMARY

NON-TECHNICAL SUMMARY GEM BRIDGE

Non-Technical Summary Prepared by Parsons Brinckerhoff Ltd July 2009 Page 3 for Devon County Council

1 NON-TECHNICAL SUMMARY

1.1 Introduction and Background

1.1.1 Devon County Council is submitting a Planning Application to build a shared cycle/walkway bridge crossing of the River Walkham Valley to improve the linkage between the two existing sections of the Devon Coast to Coast National Cycle Network route in this location. The bridge, to be known as Gem Bridge, would carry the cycle/walkway approximately 24m above the River Walkham Valley to avoid steep gradients through this very hilly area. The location of the scheme is shown in Figure 1 below.

Figure 1 Site Location

1.1.2 The Devon Coast to Coast National Cycle Network route, also under development by

Devon County Council, aims to increase cycling and walking in Devon by providing non-motorised transport routes between centres of population. The National Cycle Network also has an important role in attracting visitors to the region. Between Tavistock and Plymouth, the route will be particularly attractive to users as it will be almost all off road.

1.1.3 Currently, an interim route has been provided through the Walkham Valley which follows a track on the northern side of the valley, over a temporary low level footbridge across the river, and then up a steep track up the southern side of the valley. However, as steep gradients are a considerable disincentive to walking and



cycling, a structure over the valley is required that will provide an acceptable gradient to carry the route thus encouraging access for cyclists and pedestrians and less able users.

1.1.4 Under the Town and Country Planning Regulations (Environmental Impact Assessment) (England and Wales) 1999, as amended, it has been determined that the Planning Application for Gem Bridge requires an Environmental Impact Assessment due to the potential impacts of the scheme which is located within a National Park. Parsons Brinckerhoff Ltd has been commissioned by Devon County Council to undertake the Environmental Impact Assessment. The Dartmoor National Park Authority will be the planning authority determining the application.

1.1.5 An Environmental Statement has been produced to report the findings of the assessment, which identifies the positive and negative environmental impacts of the scheme and recommends measures to lessen those impacts. This Non Technical Summary outlines the predicted environmental impacts, as documented in the Environmental Statement, in non-technical language.

1.2 Description of the Scheme

1.2.1 The scheme alignment would be similar to the original Walkham Viaduct which formed part of the South Devon and Tavistock Railway. The former masonry viaduct, originally a Brunel design and partially reconstructed in 1910, has been described previously as one of the most spectacular of Devon’s many viaducts. The viaduct was demolished in the 1960s and the remains lie on the valley floor.

1.2.2 The scheme aims to recreate, to some extent, the form and appearance of the former railway viaduct. A photomontage showing the proposed bridge arrangement and appearance is shown in Figure 2.

Figure 2 Proposed Bridge Arrangement over River Walkham

1.2.3 The proposed bridge comprises a 5 span, 200m long (30m-40m-60m-40m-30m)

tubular steel structure with a concrete bridge deck. The structure would be supported on reinforced earth bank abutments and three “wine-glass stem” shaped concrete piers with a granite finish. The bridge would carry a 3.5m wide cycle/walkway and



would also provide viewing areas over the valley. The bridge has been designed to maintain a 1:20 gradient to provide easy access for cyclists and pedestrians including less able users.

1.2.4 A temporary fabrication area would be required for the assembly of the bridge superstructure. A temporary haul road over the River Walkham would also be required for access to the southern bank of the river. Both would be removed on completion of the construction works which are expected to last approximately 15 months.

1.2.5 During construction, the immediate area would be closed to the public. The Public Right of Way along the river would be temporarily diverted but, once complete, the scheme would provide improved access to the riverside path via new timber steps to be constructed down the southern side of the valley. .

1.2.6 The scheme would include reinstatement of the local landscape affected by interim route development works, through the removal of the temporary low level footbridge and the removal of the track on the northern side of the valley, installed to service the temporary route. That track alignment would be restored using planting of native tree species.

1.2.7 Elements of the former viaduct, including the capping stones and the original Brunel embankment to the north of the valley, have been salvaged and would continue to be displayed in-situ as part of the scheme. The scheme is located in an area of historic mining, impacts upon the remains of which have been minimised in the design of the scheme.

1.3 Alternatives Considered

1.3.1 The existing temporary low level footbridge could not be used as a permanent solution for the Walkham Valley crossing since consent for its construction was only permitted by the Environment Agency as a temporary measure prior to the introduction of the scheme. Given this, and the steep gradients as discussed above, the ‘do-nothing’ option in which no bridge is constructed has thus been discounted.

1.3.2 The horizontal alignment was determined such that the scheme could be constructed within the boundary of the original railway land thus reducing the environmental impact on the surrounding area. The alignment selected also avoids the disused mine workings.

1.3.3 Originally, the bridge was designed to be a 140m long (40m-60m-40m) 3–span structure suspended on one central pier with earth abutments to either side of the river bank. However, this proposal would have required a large amount of earthmoving to raise the ground level at the valley sides and would have presented a risk to the mining remains.

1.3.4 To reduce the volume of earthworks, it was decided that the bridge span should be increased. Consequently, the overall span was lengthened to 200m and introduced two additional spans, one at each end of the original bridge alignment, providing a 5-span structure.

1.3.5 Consideration was given to suspension/cable-stayed type structures. The towers required for a bridge of this scale would have projected well above the existing tree line on the hilltops and would be prominent in the landscape. Such “statement” structures were not considered appropriate for this rural National Park location which requires a design that is as unobtrusive in the surrounding environment as possible.



1.4 Assessing the Impacts

1.4.1 The Environmental Impact Assessment process has considered a range of topics that have been agreed with the Dartmoor National Park Authority as relevant to the scheme both as a result of the characteristics of the scheme’s location and due to the nature of the proposal. These topics are, in alphabetical order:

Air Quality;

Cultural Heritage;

Ecology and Nature Conservation;

Ground Conditions;

Hydrology, Drainage and Water Quality;

Landscape and Visual Assessment,

Noise and Vibration;

Pedestrians, Cyclists, and Community Effects;

Planning and Policies;

1.4.2 Potential disruption during construction has also been assessed during the Environmental Impact Assessment process (the findings and recommendations from this section will also be set out in a Construction Environmental Management Plan for reducing construction impacts). Cumulative effects with other schemes in the area have also been considered.

1.5 Summary of Environmental Impact Assessment

1.5.1 The Environmental Impact Assessment process identifies ways of minimising any potential negative impacts of a scheme and in doing so guides the design to reduce those impacts. As a result of the assessment process, the design of the scheme has been adapted to include these recommendations in order to achieve ‘mitigation by design’.

1.5.2 The following provides a summary of the main findings and recommendations arising from the Environmental Impact Assessment process.

Air Quality

1.5.3 There is potential for a temporary, slight adverse impact on air quality during the construction phase as a result of dust generation, particularly during prolonged periods of dry weather. This would be managed via simple control measures, such as damping down during site works and use of wheel washes for vehicles existing onto the public highway. These measures would be implemented via the Construction Environmental Management Plan.

1.5.4 No impact on air quality is expected from the operation of the scheme.

Cultural Heritage

1.5.5 No known archaeological remains or other historical artefacts, including the original Brunel footing or features such as the leats and adits associated with former mine workings in the area, are expected to be adversely impacted by the construction or operation of the scheme.



1.5.6 Should any additional archaeological features be encountered during future ground investigation or construction works, all works would cease immediately and liaison with Dartmoor National Park Authority would be undertaken to decide upon the need for their recording and/or an archaeological watching brief.

Ecology and Nature Conservation

1.5.7 The scheme location, and adjacent areas, contains a number of species and habitats of varied conservation value and biodiversity interest with otters, bats and fish identified as being of greatest value.

1.5.8 Adverse impacts on these would be minimised by a range of measures including the siting of the fabrication area away from the bank of the River Walkham and the reinstatement of the fabrication area at the end of construction. Some trees would require removal to make room for the fabrication area and bridge landings but these are in the main low quality specimens. Restoration planting would be designed to mitigate the loss of vegetation from the construction of the scheme. Tree felling and scrub clearance should be scheduled to avoid impacts on bird nesting and disturbance to breeding and hibernating bats.

1.5.9 With the implementation of mitigation measures as above, it is considered that there would not be any significant negative impacts from the construction or operation of the scheme and there would be some positive effects at a local level from the reinstatement works proposed.

Ground Conditions

1.5.10 Some potential for health impacts could arise at the construction stage of the scheme associated with the soil containing elevated concentrations of naturally occurring heavy metals, including arsenic, as a result of historical mining in the area.

1.5.11 Precautionary measures, including the wearing of gloves and damping down of soil during dry and dusty conditions, would be sufficient to protect construction workers during groundworks. Excavated soils would be assessed for their re-use on site. If they were not suitable, because of elevated levels of heavy metals, they would be disposed of at an appropriate waste disposal facility.

1.5.12 No adverse impacts as a result of ground conditions would be expected from the operation of the scheme.

Hydrology, Drainage and Water quality

1.5.13 There is no risk that Gem Bridge would flood because it would be well above the 1 in 1,000 year fluvial flood level. The abutments and piers would be outside the flood plain and thus the scheme would not increase the risk of flooding downstream.

1.5.14 A small amount of flood storage area would be temporarily lost during construction as a result of any ground raising but the Environment Agency has confirmed that this would be insignificant with regard to increased flood risk downstream. These levels would be returned to existing on completion of the construction works.

1.5.15 Any risk of pollution as a result of increased surface water run-off during construction or accidental spillage of construction materials would be mitigated by the implementation of the Construction Environmental Management Plan

Landscape and Visual Assessment



1.5.16 There would be temporary very localised adverse landscape and visual impacts during the construction phase but these works would not be visible to the public and the area would be reinstated on completion of construction.

1.5.17 The bridge has been designed for low visual impact and would be sited close to the line of the former railway bridge thereby minimising impact on the landscape. The scheme is likely to have a beneficial impact on the character and appearance of the Walkham Valley as a result of the removal of the existing low-level footbridge and the reinstatement of areas used for its construction of the footbridge.

1.5.18 On completion, views of the bridge from the public footpath and the few nearby residential properties would be limited due to the existing topography and tree cover with greater screening and landscape integration provided as new planting associated with the scheme matured.

Noise and Vibration

1.5.19 Noise and vibration during construction would be short term and would be managed by implementation of the Construction Environmental Management Plan.

1.5.20 No additional noise impact of noise is expected from the operation of the scheme since the area is already used for similar recreational purposes.

Pedestrians, Cyclists, and Community Effects

1.5.21 The development of the scheme will cause some slight disruption to walkers and cyclists accessing the Public Right of Way along the river bank. Road users could be affected as a result of construction traffic. The impact would however be short term. Impacts on road traffic would be minimised via the use of traffic management measures and the implementation of the Construction Environmental Management Plan.

1.5.22 The operation of the proposed Scheme is anticipated to have a beneficial impact on walkers, cyclists and the local community by providing opportunities for leisure and exercise. It is also expected to encourage local economic growth as a result of spending by visitors.

Planning and Policies

1.5.23 The scheme is considered to be consistent with national, regional and local strategy and policy guidance as it will promote sustainable travel and enjoyment of the Dartmoor National Park while preserving and enhancing landscape, wildlife and cultural heritage. Any adverse impacts incurred with relation to the above policies have been minimised by the design of the scheme and through the ecological and landscape reinstatement proposed.

Disruption Due to Construction

1.5.24 Disruption due to construction activities would be managed by the implementation of a Construction Environmental Management Plan which would identify clearly and concisely how the potential environmental issues associated with the scheme would be managed in line with all legislative and regulatory requirements and best current practice.



1.5.25 The Construction Environmental Management Plan would be extended to all subcontractors involved in the project and would be subject to regular independent audits by Devon County Council.

Cumulative Effects

1.5.26 A review of planning documents and proposal maps for the local area has not identified any significant developments likely to have a planning application submitted in the foreseeable future. As a result, there are considered to be no cumulative effects as a result of the construction of the scheme.

Environmental Impact Assessment Conclusions

1.5.27 Predicted likely impacts have been mitigated effectively either through ‘mitigation by design’ as an inherent part of the design process, or through additional mitigation measures such as landscape planting or control procedures (such as tree protection and traffic management plans) to be implemented during construction.

1.5.28 Following the implementation of the control measures and design features which have been proposed during the Environmental Impact Assessment and which form part of the scheme development, it is predicted that no significant adverse effects will remain in the long term.

1.5.29 There will be beneficial landscape, socioeconomic and health effects of the scheme which will help deliver planning objectives at the local and regional level by stimulating tourism, leisure and sustainable transport opportunities.

Documents

GEM BRIDGE ENVIRONMENTAL STATEMENT...Network route in this location. The bridge, to be known as Gem Bridge, would carry the cycle/walkway approximately 24m above the River Walkham