Project Overview

This project is being showcased as part of UKGBC’s Biodiversity and Environmental Net Gain Project.

Four locations prioritised with the highest national visual impact following a Landscape and Visual Impact Assessment Study completed by National Grid. The first section to come forward is the VIP Peak District East Project. 

Overhead lines located close to areas of nationally important landscapes and not surprisingly areas with ecological value. 

“Our Visual Impact Provision project makes use of an allowance of £500m by Ofgem across Great Britain to carry out work which will help to reduce the impact of existing electricity transmission lines in English and Welsh AONBs and National Parks.”  – National Grid. 

The project proposed the following:  

  • 1.7km section of 400Kv Overhead Line (7 pylons and existing substation) to be removed east of Woodhead Tunnel; Dunford Bridge. 
  • Underground cable installation and connection to existing cables (in tunnel). 
  • New sealing end /sub station and new terminal connection tower. 
  • Temporary Trans-Pennine Trail (TPT) diversion route to be provided. 
  • To be delivered with at least 10% BNG 

Key Sustainability Objectives/outcomes and Approaches Used

The Peak District project contributes to the creation of grassland habitat along the opened up Trans-Pennine Trail (TPT) corridor and addresses the encroachment effects of secondary woodland. The project was based upon landscape driven benefits – conflicts with ecological or perceived potential ecological benefits – particularly for an overhead line which has been there since the late 1960’s. A key aspect of the planning submission commitment was the completion of a BNG assessment to determine the project losses and where a >10% commitment to BNG could be achieved by National Grid. This was calculated by in-house AECOM Ecologists and in-house AECOM Landscape along with BNG and GIS specialists. A lot of time was spent working with the project engineers looking into the temporary impact and land take required to interpret the DEFRA metric to avoid falsely inflating the baseline and therefore accurately reflect the impacts.

Key Sustainability Objectives/Outcomes and Approaches Used

  • A commitment to an Ecological Management Plan for TPT corridor and Wogden Foot Local Wildlife Site (LWS).
  • Habitat Enhancement measures for willow tit secured in non-affected areas of LWS.
  • Tree Planting (On and Off site) additional to Biodiversity Net Gain (BNG) to replace more than 4,000 trees.
  • Invasive Species control was secured via Landscape and Ecological Management Plan (LEMP).
  • Statutory designations and land potentially linked to wider SPA sites to consider. A habitat Regulations Assessment screening was required to inform by year-round bird surveys.
  • Presence of Local Wildlife Site (LWS) – old railway sidings (Wogden Foot) as such distinct different composition to local habitats – and only flat piece of land alongside Trans-Pennine Trail cable corridor route, where the new substation was to be located.*
  • A linear Green Corridor – this included a vegetated TPT corridor feature combined with River Don within the valley landscape.
  • Reinstatement of habitats within LWS – successional habitats – the effect of ‘turning back the clock’ – this included seed harvesting, scrub removal, and future grassland/grazing management.
  • For on and off-site areas, a 30-year Habitat Management Plan was prepared for a local quarry site which was calculated to deliver ~33 units through heathland enhancement and achieve a ~12% net gain in biodiversity units, over the 10% BNG target.

AECOM conducted an off-site enhancement site options review within a 5 km radius of the project (and within Barnsley MBC area) to determine potential locations to offer net gain credits.  A location off-site was chosen because of limited opportunities available for uplift onsite, as the project is within a national park and needed to maintain the functionality of the trail and the Local Wildlife Site. AECOM maximised on-site gains where possible, at planning permission detailed in landscape plans. Off-site provided the opportunity to go further afield to meet habitat requirements.

*Secured via a S106 Agreement

Lessons Learnt

  • Starting BNG requirement discussions at earliest opportunity.
  • We will seek to work with stakeholders and ongoing conservation projects wherever possible.
  • Landscape and topography constraints working area within valley with significant engineering considerations for installation of underground cables between TPT requirements – which needed to be kept open throughout construction – River Don and steep sided valley (with additional ecological designations/constraints).
  • On-site loss of -70 biodiversity units in absence of any enhancement measures.  While on-site credits were achieved via restoration, creation and avoidance of habitats and a landscape plan. However, there remained an overall net loss of ~21 units.
  • One challenging aspect of the project was offsetting in line with the ‘trade off’ rules as the site is in a valley; the majority of close-by habitat is upland typography, and therefore too different. AECOM therefore had to go outside the area to find a suitable space for woodland enhancement.