Environmental controls during construction will include ecological supervision by an Ecological Clerk of Works, pollution prevention measures, and careful timing of works to minimise disturbance to sensitive species such as Little Terns and Overwintering birds.
Minimising impact to the environment during construction
The construction method
The use of horizontal directional drilling (HDD) allowed us to lay cables underground by drilling underneath the sand dunes, instead of digging through them. This trenchless technique minimised:
- the removal of any sand;
- disturbance to the ground surface; and
- interference with the flood defence characteristics.
This helped to ensure that there were no direct impacts to Talacre Brook, the Talacre dune system, the Gronant Dunes and Talacre Warren Site of Specific Scientific Interest (SSSI) and the area of grassland that forms part of the Dee Estuary Special Area of Conservation (SAC) and Special Protection Area (SPA).
Construction practices
Our construction contractor, Boskalis, will undertake all site works in accordance with current guidance and best practice to protect the environment:
- Task-specific lighting will be used when required for the safe delivery of works at the lowest brightness level possible. Lighting will be designed and positioned to reduce light pollution into adjacent properties and habitats.
- Fenced boundaries will be reinstated, gaps in hedgerows will be replanted, and grassland will be cultivated. Fencing will be installed in areas of grassland reinstatement to allow the re-seeded grass to establish.
- Measures for pollution and dust controls will be implemented to minimise the likelihood of habitat degradation during construction.
- A temporary raised platform will be installed to keep construction plant and equipment safe in high tides, as well as reduce the risk of accidental release of fuel into the environment. It will be removed once construction is complete.
Ecological Clerk of Works (ECoW)
An ECoW has been appointed to support, oversee and monitor Boskalis during the works. The ECoW’s role includes, but is not limited to:
- Undertaking or overseeing pre-construction surveys for protected species.
- Providing ecological advice to the contractor to ensure Boskalis staff are aware of their responsibility with regards to wildlife and sensitive habitats.
- Monitoring ecological conditions to identify any constraints.
- Overseeing the implementation of mitigation measures to ensure compliance with protected species legislation, licensing and commitments in the Environmental Statement (ES) and Construction Environmental Management Plan (CEMP).
Protecting wildlife
Our construction programme focuses on minimising the impact on the environment, wildlife breeding periods, local community, and port movements. To achieve this, we have planned our construction programme and groundworks to avoid the breeding and/or hibernation seasons as far as is reasonably practicable to minimise disturbance to the:
- Little Tern (breeding season is between mid-April to mid-July)
- Cetti’s Warbler (breeding season is between late March to mid-April)
- Natterjack Toads (breeding season is approximately April to July)
- Great Crested Newt (hibernation season is typically October to March)
A pre-construction survey as well as ongoing surveys will be carried out at Warren Farm and the sand dunes to identify and monitor Natterjack Toads, Sand Lizards and Great Crested Newts. If their presence is confirmed at any stage, works will cease, and the ECoW will be contacted to advise on the best way to proceed.
Additionally, the targeted burial depth of the HDD conduit means disturbance to protected species and their dune habitats is not anticipated. For example, Natterjack Toads typically burrow less than 50cm deep, and Sand Lizards up to around 1m, which is shallower than the conduit’s 15 m depth.
Environmental documents
If you would like further information on environmental protection and mitigation measures, you can view these documents here.
- Environmental Studies Report – Cultural Heritage, Biodiversity, Arboriculture
- Stage 1 and 2 Habitats Regulations Assessment
- Water Framework Directive (WfD) Assessment
- Net Benefit for Biodiversity (NBB) and Green Infrastructure Statement
- Construction Environmental Management Plan (CEMP)
Gronant Dunes