Morlais Tidal Energy project: botanical survey using roped access and drone techniques

Overview

BSG Ecology completed survey of cliff vegetation using roped access and drone survey techniques. The approach to the work was agreed with Natural Resources Wales. In the event the cable route from the proposed tidal energy project needs to be pinned to the cliff, the results will help minimize impacts on botanical communities of high conservation interest.

Challenge

BSG Ecology was commissioned in May 2020 to undertake a botanical survey of sea cliff vegetation to inform the possible location of a cable route for the Morlais tidal energy project in North Wales.

The cliff is within a Special Area of Conservation (SAC) and Site of Special Scientific Interest (SSSI); the cliff vegetation is one of the key interest features of these designations.

The preferred option for installing the cabling is by horizontal directional drilling under the cliff as this approach would avoid impacts on cliff habitats. If this is not possible, a secondary option involves pinning the cables down a section of the cliff.

Following consultation, carried out as part of the environmental impact assessment, further information to assess possible impacts on SAC and SSSI cliff vegetation was requested by Natural Resources Wales. The cliffs in the local area support several rare plant species, and the presence of these [1] also needed to be determined.

This presented a challenge as the cliff is approximately 40 m high with a tidal base and very difficult to access and survey.

Solution

An approach was devised that involved a combination of aerial filming using a drone and rope access techniques to safely survey the cliff face.

The drone was used to systematically photograph the cliff vegetation from a distance of 2 m. The photographs from the drone survey document vegetation across the whole cliff face and are of a sufficient resolution to allow identification of the majority of plant species.  This was complemented by a National Vegetation Classification (NVC) survey. Quadrats were used to sample vegetation, and rope access techniques to safely inspect the cliff face.

The survey work was carried out by Principal Ecologist Guy Miller, with technical advice from BSG botanists Dr Tom Flynn and Caroline O’Rourke.

Outcome

The combination of techniques proved an effective way to survey the cliff, and the resulting data have been used to identify suitable cable route options that will minimise the risk of impacts on vegetation.

Natural Resources Wales has confirmed that our survey approach was effective and that our survey report provides a competent description of the cliff vegetation.

Testimonial

“BSG Ecology actively engaged with Natural Resources Wales alongside the project to agree the scope of works, completed challenging botanical survey work and delivered a robust data set. In the event that pinning the cable to the cliff is the required option, it will help us minimize impacts on vegetation while also helping deliver a nationally important tidal energy project.”

James Orme, Morlais Energy

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[1] Including spatulate fleawort Tephroseris integrifolia subsp. maritima, spotted rock-rose Tuberaria guttata and golden hair lichen Teloschistes flavicans

Region

Category
Biodiversity, Infrastructure, Projects, Wales