Twyford Down Project
In February 1990, the decision was taken that the final section of the M3 motorway would follow an easterly route through Twyford Down. Although the route chosen would run through land that was largely agricultural, it would affect the East Hampshire AONB, parts of the St Catherine's Hill and the Itchen Valley SSSI, and would isolate the most easterly parts of the St Catherine's Hill SSSI, the "Dongas" with its colony of Chalkhill Blue butterflies.
Due to concern about losses of habitat, it was proposed to recreate downland on top of Twyford Down, on an area of arable land surrounding the Arethusa Clump, and on the restored route of the existing Winchester bypass (A33). This would create areas of downland considerably greater than those to be lost, and it would provide a link between the water meadows and St Catherine's Hill.
Since 1990, staff from the Institute of Terrestrial Ecology have been acting as advisors in order to ensure that the construction of the road had the minimum effect on wildlife and to suggest methods by which a range of habitats could be created on land made available by the motorway construction.
Following the decisions of Public Enquiries, it was expected that there would be scope for habitat creation which would considerably increase the area of chalk grassland, a habitat which is in decline nationally. Although the line of the motorway was fixed, there was considerable scope for modifying construction procedures to take account of wildlife.
As a first step, the animal and plant communities were surveyed along the route itself, and also in the adjacent areas, particularly the SSSIs. The purpose of this was:
The surveys showed that there was no particular problem with either deer or badgers on the chosen route, and therefore no special provision would be needed. However, two areas of grassland of interest were identified.
The first was a small area of flood meadow which would be lost. The area was found to contain no particularly rare species, but was a good example of a declining habitat type and therefore merited translocation for use elsewhere, if possible.
The second area was located at the northern end of Twyford Down in as limb of the
St Catherine's Hill SSSI, known locally as "the Dongas". These are thought to be
ancient trackways connecting Winchester with the Down. Although much of the Dongas