Client
OCU Group / Dŵr Cymru Welsh Water
Services
- Specialist Planning Advice
- Development Management
- Environmental Impact Assessment Screen Request
Dŵr Cymru Welsh Water is investing in infrastructure upgrades through its AMP8 National Environment Programme to improve environmental performance and water quality. The proposed scheme involved constructing a new 3km transfer pipeline to convey flows from Cilcain WwTW to Maes-Y-Groes WwTW, where spare treatment capacity exists. Once operational, the existing treatment processes at Cilcain were to be decommissioned and replaced by a pumping station. The project was required to meet revised environmental permit requirements due to come into force by December 2027 and would contribute to improved water quality within the nearby river system and Special Area of Conservation (SAC).
The proposed route passed through an environmentally sensitive landscape containing the Clwydian Range and Dee Valley National Landscape (formerly AONB), the Alyn Valley Woods SAC and the Alyn Gorge Caves Site of Special Scientific Interest (SSSI). The route also crossed several watercourses, public rights of way, agricultural land, and the setting of a listed building.
Caulmert were instructed to prepare and submit an EIA screening request to Flintshire Council, seeking to demonstrate that the work would not have an adverse effect on the environment and that Welsh Water could proceed with the development under their Permitted Development Rights without the need for a planning application and supporting Environmental Statement.
The Challenge
Although the pipeline occupied only approximately 0.04 hectares and fell below the relevant Schedule 2 threshold, its location within and adjacent to multiple internationally and nationally designated environmental sites meant that the Local Planning Authority (LPA) needed to carefully consider whether the proposal could give rise to significant environmental effects by virtue of its sensitive location.
Particular concern centred on six sensitive ‘pinch points’ where the route interacted with designated sites and crossed the River Alyn. Caulmert also needed to ensure that Flintshire County Council had sufficient information to avoid adopting a precautionary approach and requiring a full Environmental Impact Assessment (EIA), which would have introduced significant programme and cost implications for the project.
Caulmert’s Role
Caulmert led the planning and EIA screening strategy from the outset. This included reviewing technical reports, ecological surveys, route options, and engineering proposals before preparing a detailed Screening Request demonstrating why the development was not likely to result in significant environmental effects.
A key element of Caulmert’s work was integrating planning, ecology, and engineering considerations into a single evidence-led case. The team reviewed the alternative options, including on-site treatment improvements and alternative transfer routes, before carefully evidencing the preferred route that reduced impacts on designated habitats and minimised disturbance to sensitive areas.
Working with the wider consultant team, Caulmert’s screening request highlighted a range of mitigation measures that would significantly reduce environmental effects. These included extensive use of Horizontal Directional Drilling (HDD) beneath roads, woodland, and the River Alyn to avoid habitat loss, protect watercourses, and eliminate the need for more intrusive construction methods. The route was selected to avoid the most sensitive parts of the SSSI and minimise interaction with ecological designations wherever possible.
Caulmert also offered more general planning advice to the consultancy team. This included recommending the completion of a shadow HRA to support the authority with its responsibilities to demonstrate that there would be no adverse effects on the Alyn Valley Woods SAC.
Project Outcome
Following review of the submission and supporting evidence, Flintshire County Council issued a Stage 2 Detailed Screening Assessment concluding that the proposed development was not EIA development and that an EIA was not required. Removing this detailed piece of work helped prevent more time being taken and extra costs being accrued via the subsequent need for a planning application and supporting environmental statement.
The Council accepted that the project was not likely to have significant environmental effects and recognised that the proposed route selection, HDD construction techniques, and mitigation measures would minimise impacts on the SAC, SSSI, National Landscape, and other environmental receptors.
The successful outcome enables Dŵr Cymru Welsh Water and OCU Group to continue progressing a critical piece of wastewater infrastructure without the need for a full EIA, maintaining programme certainty while supporting long-term improvements to environmental compliance and river water quality.
The decision also demonstrated the value of a robust, evidence-led screening strategy and highlighted Caulmert’s ability to guide complex infrastructure projects through environmentally sensitive planning challenges.
Client Comment
“Caulmert were appointed as the planning consultancy support on this project based on their knowledge and experience of dealing with DCWW schemes and their ability to lead on a multi-disciplinary approach. The tight timescales associated with the submission of the EIA screening request were not a barrier to Caulmert reviewing the scheme details and they subsequently produced a robust submission that was screened out by FCC and has ultimately enabled us to ensure we can deliver this critical project in line with our programme, thus ensuring we meet our regulatory commitment of achieving environmental improvements to the SAC”.
