Colway Gate

Colway Gate is a new residential development perched above Lyme Regis on a steeply sloping coastal site with variable and challenging ground conditions. EGY was appointed to deliver three integrated services: sustainable drainage design, site-wide external levels, and bulk earthworks volumetric analysis. The earthworks strategy alone removed 92 lorry movements from the construction programme.

The site’s topography drives everything. Steep gradients mean surface water runs fast, external levels require careful coordination to remain accessible and constructible, and earthworks are expensive to manage if the strategy is wrong. Getting all three right simultaneously, and making sure they inform each other, was the core engineering task.

Drainage on a coastal slope

EGY designed a sustainable drainage strategy that responds to the site’s natural contours, using SuDS techniques to control runoff and reduce the environmental impact of the development on the coastal setting. The strategy achieves an average removal of 80% of silt, heavy metals, and hydrocarbons — without relying on buried attenuation infrastructure.

Levels and earthworks

The external levels design coordinated drainage performance, accessibility, and visual quality across the development, while minimising the extent of retaining walls. Retaining walls are expensive, require maintenance, and constrain the character of a hillside scheme. Reducing their extent through careful levels design was a meaningful win on programme and cost. The bulk earthworks analysis optimised the movement of cut and fill across the full site. The result was a balanced earthworks strategy that removed 92 lorry movements from the construction programme — reducing cost, carbon, and disruption to the access routes serving the development.