Highways Agency

A249 Iwade Bypass to Queenborough Improvement (part of the A249 Stockbury (M2) to Sheerness DBFO)

The A249 Iwade Bypass to Queenborough Improvement Scheme

The A249 Iwade Bypass to Queenborough Improvement is the last of four schemes to improve the A249 between the M2 and the port of Sheerness. The improvement will provide a dual carriageway road 5km long between the end of the Iwade Bypass and Queenborough and will include a new high level crossing of The Swale.

The new bridge, which will be 1.27 km long, will rise to a height of 34.7m above The Swale. This will provide 29m clearance for shipping above high water level and also give the required clearance over the existing approach to Kingsferry Bridge on the south side and the railway on the north.

The route then joins the line of the existing A249 as far as the junction with Ferry Road, before moving away to a new roundabout at Cowstead Corner. A section of new local road will be constructed alongside the new Trunk Road to maintain a link between Kingsferry Bridge, which will be retained, and Cowstead Corner for local traffic movements. This local road will provide for pedestrians and cyclists, as they will not be permitted to use the new bridge crossing. The new A249 dual carriageway will then continue to the south of Queenborough Road, via a roundabout at Neatscourt to cater for a proposed development, to a new signal controlled junction with Main Road at Queenborough. From here, the Trunk Road will narrow to a single carriageway to tie into Brielle Way.

The dual carriageway will have a speed limit of 70mph between Kingsferry and Neatscourt and between Neatscourt roundabout and Brielle Way the speed limit will be 50mph.

The proposed scheme has been designed to:

• limit disturbance to flora and fauna;
• minimise land take as far as possible in protected areas;
• provide compensation land to replace that taken by the scheme (this is not part of the DBFO Project);
• create new wildlife habitats;
• reduce visual intrusion by utilising high quality bridge design;
• provide new pedestrian and cycle routes;
• provide new drainage systems to avoid pollution;
• reduce noise levels by moving the road away from residential properties where possible and by providing noise barriers, including earth mounding; and
• minimise light pollution.

The New Bridge

The viaduct is made up of 19 spans, which vary in length from 44m at the ends to 92.5m in the centre.

The viaduct construction comprises four steel girders with a reinforced concrete deck all supported on reinforced concrete columns and foundations. The girders vary in depth between 1.8m to 3.2m and the total weight of steel used will be 10,000 tonnes. There will also be 29,000m3 of concrete used.

The Environment

The key issue which has influenced the design of the scheme is the need to protect the local environment.

The route of the new road crosses areas of international significance for birds, and includes areas classified as Sites of Special Scientific Interest (SSSI). A number of design features have been incorporated in the scheme to mitigate the impact on the environment, for example the widths of embankments have been kept to a minimum to reduce the amount of land taken, and drainage has been carefully designed to ensure that there is minimal impact on the ecology of the marshes. To further mitigate the impact of the work on the landscape, replacement sites for flora and fauna have been established at Chetney Marshes on the mainland.

Advanced environmental surveys were carried out to identify any wildlife likely to be affected by the construction of the scheme, and as a result, during the autumn of 2003, water voles were carefully removed to temporary accommodation.

The translocation strategy for the voles, which was agreed with the Environmental Agency and English Nature, involved the removal of the animals from within the line of the proposed highways works using approved traps. Forty eight animals were captured and these are being held at a wildlife centre where they are being monitored pending release back to the site. In the meantime, fresh ditches have been dug and planted with appropriate food and cover species in areas that are not affected by the works, so as to create a suitable new habitat to compensate for the areas lost. The new ditches are protected by exclusion fencing until the new habitat has become sufficiently established to support the animals following their release. After release the animals will be monitored to ensure the viability of the population.

Protecting our History

We anticipated that works to construct the new Swale Crossing would unearth artefacts of historical interest so a team of professional archaeologists were asked to assist on-site at the commencement of works. Several finds were made this summer dating back to the Iron Age and Romano-British periods. The area south of Cowstead Corner Roundabout showed activity relating to the ancient foreshore, revealing pits filled with pottery, shells and refuse. In addition a large number of cremation burials were found at three sites next to the existing A249 close to Neatscourt, where jewellery was found in an area that is believed to have been the edge of a settlement. Areas of interest have been fully excavated and the findings have been conserved, analysed and recorded. Although there is no central county store for archaeological materials in Kent, we hope that these findings will be displayed for public view at a suitable location on the Isle of Sheppey sometime in the future.