Essex County Council’s £15m strategic investment

Targeted as an innovation project by Morgan Sindall, the A414 upgrade to Edinburgh Way in Harlow, Essex, will be the first installation of a large-diameter, complete structural wall plastic pipe attenuation system directly beneath a live carriageway.


Designed entirely around Polypipe’s Ridgistorm-XL pipe and chambers, the adopted system has been value-engineered to provide optimised storage, sediment removal and flow control of the increased levels of stormwater run-off generated by the dualling of the existing single-lane highway.

The original drainage and attenuation design was based around installing twin 900mm pipe runs on either side of the newly dualled carriageway. With limited verge space and complex below-ground utility runs in the area, we saw an opportunity to re-engineer the scheme around an extended single run of 1500mm large diameter plastic pipe, with integrated water management chambers below the highway. This would greatly simplify installation, improve health and safety and ultimately provide a more cost-effective long-term solution.

In order to gain Approval in Principle (AIP) for the redesign, Morgan Sindall had to present a detailed technical submission to Essex Highways, as the use of any pipe over 900mm in this situation represented a departure from the standards defined within the Specification for Highways Works.

Morgan Sindall Infrastructure’s consulting engineer, White Young Green, had previously worked with Polypipe on similar innovation schemes and developed the new proposal around its Ridgistorm-XL system.

From the outset, Polypipe worked alongside the consulting engineer team, providing all the required geotechnical and material performance data required for the AIP application. With this being a first for Essex Highways, the level of detail needed was understandably high, so the experience of the Polypipe team proved invaluable in achieving a successful outcome.

Essex County Council’s £15m strategic investment in the Harlow Road network is designed to relieve congestion, improve road safety and support local economic growth.

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