Client: Harworth Group
Location: St Helens
Wilde were appointed by the Harworth Group to provide highway, drainage and bridge engineering services for a proposed 56 acre residential development site for 900 new homes in St Helens.
The site, which was previously used as a colliery, is a mile from St Helens town centre and is categorised as brownfield.
The site is accessed to the north by a masonry arch bridge spanning Sutton Brook. No previous information relating to the structure was available. Inspection and assessment work was carried out by WCL’s bridge engineers to determine if the bridge needed to be strengthened to facilitate vehicular access to the site. An options report was prepared which included recommendations / costings for strengthening, replacing and maintaining the bridge.
The highway infrastructure is to be adopted by St Helens Council as part of a Section 38/278 Agreement. WCL worked with the Council to incorporate their requirements into the design.
WCL designed the 650m spine road which has 6 priority junctions and 5 minor road junctions which will feed the residential development. Amendments were made to an existing four arm roundabout by creating an additional arm to provide access to the Moss Nook site.
It was also necessary to design a new priority junction and the street lighting. Traffic calming measures including new off-site footways and cycling facilities, which were funded from Section 106 developer contributions, were designed by WCL’s highways and traffic engineers.
WCL also developed a comprehensive site-wide foul and surface water drainage masterplan.
The SuDS drainage strategy utilised ponds and swales to attenuate flows of surface water to the adjacent watercourse to avoid rapid changes in river flows.