Ecology services, South Wales Valley Lines Electrification Scheme

The brief

In 2012, ABC Electrification started work on behalf on Network Rail to deliver the electrification of the South Wales Valley lines between Ebbw Vale Parkway and Cardiff, and between Rhondda Cynon Taf and Merthyr Tydfil, covering a total distance of 205km. As part of the electrification works, ABC Electrification will be installing 344km of Overhead Line Equipment (OLE) and constructing 8000 overhead line structures. This would involve alterations to bridges, platforms and station buildings along with associated sub-stations and construction compounds. Thomson Ecology was commissioned to offer advice on any ecology constraints on the works.

What we did

Thomson Ecology provided a range of ecological support.

  • A desk study collating data from South East Wales Biodiversity Records Centre (SEWBReC) and ten local councils. The desk study included over 18,000 protected species records, and reports on nine internationally protected sites within 5km, 54 nationally designated sites and 657 locally designated sites within 2km.
  • A desk based Phase 1 habitat survey using analysis of aerial imagery and train cab video footage. Aerial imagery was used to map and classify the habitat types present. The video analysis used footage taken from the train cab to identify stands of invasive plant species and structures that could have the potential to support roosting bats. Using these methods, 37 habitat types were identified and 132 structures were assessed for their potential to support roosting bats.
  • Field based Phase 1 habitat surveys for a 45km length of railway where no video footage was available for analysis. Aerial imagery was used alongside the field survey to analyse areas which were not accessible on foot. These methods identified a further 22 habitat types.
  • The Phase 1 surveys identified habitats along the route with the potential to support bats, badgers, dormice, great crested newts, reptiles, breeding birds, water voles, otters, white-clawed crayfish, protected plant and invertebrate species, and also stands of invasive plants. Further surveys for these species and groups of species have been recommended.

Recommendations and outcomes

Thomson Ecology’s innovative approach to the Phase 1 habitat survey maximised time efficiency and cost effectiveness. We continue to work with ABC Electrification as the scheme develops and provide ecological advice and consultation in a timely manner.