A303 Sparkford to Ilchester dualling

The single carriageway section of the A303 between Sparkford and Ilchester, Somerset, suffers from congestion and queuing, particularly during the summer months and at weekends, and higher than average accident rates.

Opportunity

The Mott MacDonald Sweco joint venture (MMSJV) was appointed to provide design input to develop the continuous stretch of dual carriageway, linking the Podimore Bypass and the Sparkford Bypass. Due to the size of the scheme, it was classified as a nationally significant infrastructure project, and we were involved from options identification and assessment through to Development Consent Order (DCO) submission and examination.

The landscape surrounding this section of the A303 is predominantly rural in nature and environmentally sensitive. Constraints include the site’s proximity to Hazlegrove House, a Grade II listed building and registered park and garden, as well as other historic buildings, buried archaeology, conservation areas, local wildlife sites, and a range of priority habitats and protected species. It was imperative that the widened road avoided any unacceptable impact on the surrounding natural and historic environment.

Solution

Our MMSJV environment and design teams worked closely throughout the optioneering stages of the scheme to ensure all environmental constraints were considered. After some consideration, two routes for the carriageway went to public consultation, with the final option chosen largely for its reduced effects on biodiversity and the registered park and garden, and to minimise construction in an unspoilt rural setting.

We established an environmental technical working group that worked closely with our environmental, heritage and landscape stakeholders, including Historic England, the National Trust and the Gardens Trust, to ensure the road was designed as sensitively as possible.

The scheme’s footprint on Hazlegrove House was a key consideration, and the environment team developed a detailed understanding of site’s sensitivity, and this was reflected in the final designs for the layout and landscaping. The designs ensured disturbed land was replaced with similar or enhanced terrain to retain the character of the existing landscape.

We undertook the statutory environmental impact assessment (EIA) and produced the EIA scoping and preliminary environmental information reports as well as the environmental statement (ES). The ES was accompanied by several supporting documents, including an environmental masterplan detailing how any impact of the works would be mitigated.

Outcome

After submitting our ES as part of the DCO application, we received no objections from the statutory environmental bodies. The DCO examination commenced in December 2018 and closed in June 2019. The environment team provided support throughout the examination process, including answering questions raised by the Examining Authority and interested parties and responding to the local impact report. The Secretary of State for Transport granted development consent for the scheme in January 2021.