Donald Insall Associates has been acting as heritage conservation architect for the project, assisting with the repair of the bridges by specifying repairs to the surviving upstream and downstream arches and facings as well as designing new parapets at street level. Matching grit-stone masonry was obtained from a nearby quarry, a likely source of the original bridge materials. This was then hand-dressed to match the existing one. The upstream and downstream cut-water piers were designed in matching stone and have been shaped to minimise the effects of the fast-flowing river on the bridge itself. The design of the new work has been based on bridges of a similar period and on an old illustration.