A303 Ilchester Flooding. Presentation to Somerset Rivers Authority Board meeting 26th October 2016. Sarah Lewis : Asset Manager

Introduction Background & historical information. Previous Assessments. How Highways England works. Progress and moving forward.

So why does it flood. The River Yeo is raised above the surrounding levels and constrained by raised banks. This overtops at some point and the floodwater makes its way to the A303 both over and via overtopping of the various overwhelmed watercourses that drain the levels in this area. At the site, the A303 is low lying and floodwater backs up and overtops at that point as it cant get though the various existing culverts, including Burlingham Bridge, a.k.a Victoria Bridge, the culvert serving Bearley Brook watercourse under the A303 adjacent the site.

After the event: It was agreed by Highways England that a series of assessments and studies should be commissioned into the resilience of the A303 at this location. Funding, Successful bid made to undertake study Timescales. Atkins Consultants have been appointed by Skanska on behalf of the then Highways Agency to undertake a study of the flood risk.

Stage 3 and onwards The assessment can be summarised as the following: The objective being to produce a report which: Outlines potential measures to alleviate the risk of flooding to the A303. Details the impact of options to third parties. Considers means which would serve to improve flood risk at Ilchester Mead.

Study and Scheme to date. Progress and moving forward. Presentation of scheme findings and preferred options . Presentation of Preferred option with outline design to stakeholders Received objections and a petition on the preferred scheme. Model required validation due to new data being available. Highways England raised concerns that no funding was available. Highways England made and was successful on a bid for further funding to progress further modelling. It was agreed to use the Environment Agency’s Modelling framework.

Working with Stakeholders 04/06/2018 Working with Stakeholders Further consultation following modelling. Consultation on outline proposals. Highways England are open to comments and suggestions on how they can communicate better with stakeholders. Questions and feedback.