Colthrop Village, Thatcham

FLOOD MITIGATION MEASURES

The site is partly at risk of flooding at times of peak rainfall, due principally to its proximity to the River Kennet; however, records of historical flooding events show that any actual flooding was limited to the banks of the river and isolated ponding on the site. Surface water flood risk meanwhile is linked to a number of small drainage channels that run through the site from west to east.

Taking the extent of any predicted flooding, we have adopted a strategy to formalise and constrain this flooding to a new route, to be cut through the site and designed as a swale or open channel. This swale would be at the centre of a landscaped green corridor, running from the north-west of the site next to the canal across to the River Kennet in the south-east, and would constrain the extent of the flood plain to that part of the site only.

By implementing this strategy, the flood plain is limited to just 16.6% of the site, with the rest outside the flood plain and suitable for development.  This is shown in the following plan:

REMOVAL OF REMAINING PAPER MILL STRUCTURES & CLEAN-UP OF CONTAMINATED LAND

One-quarter of the site is brownfield land associated with the former Colthrop Paper Mill.  While the mill buildings have all been demolished, a number of structures remain on the site, included a substantial concrete water tower and a gantry carrying pipes across the canal.  Former slurry pits have been filled and the residue of industrial processes remains.

A preliminary assessment of the risk of contamination has been carried out, which has identified a history of manufacturing on the site since Victorian times (latterly of paper and cardboard production) and the storage and use of raw materials and by-products, as well as residual demolition material and landfill.  It is by no means unusual for brownfield land to be contaminated as a result of its previous industrial uses, and this can be successfully managed by appropriate mitigation and remediation measures.

At no expense to the public purse, the remaining structures on the paper mill site would be removed as part of the Colthrop Village project, resulting in a significant improvement to visual amenity. In addition, the development will finance the clean-up of all contaminated land, which might involve removal of material or on-site treatment.  These kinds of direct actions are typical when it comes to the redevelopment of brownfield land.

Though the land does not present any safety issues in its present state, leaving the land contaminated of course does nothing to address the possibility that it could impact on the neighbouring land and waterways.  It is therefore a great benefit of our proposals that they would clean-up the land and remove this possibility entirely.

NEW GREEN INFRASTRUCTURE

In addition to the removal of unsightly “grey” infrastructure, the Colthrop Village development would include significant investment in new “green” infrastructure. The development would be set within a framework of indigenous new planting, with hundreds of new trees and thousands of smaller plants providing a canopy of vegetation across the site.

From formal tree-line boulevards to winding riverside walks, the development would have 30% of its area dedicated to publicly accessible green space: over 10 hectares of high quality landscape for residents to enjoy, and a mosaic of new habitats greatly enhancing the biodiversity of the site.

REMOVAL OF ELECTRICITY PYLONS

The undeveloped part of the site is visually dominated by the presence of electricity pylons and high voltage cables, resulting in a significant disfigurement to the landscape. For that reason, our plans include provision for the complete “undergrounding” of the cables across the site and removal of the associated pylons.