Llandarcy Lagoon Drainage Challenge | Port Talbot, Wales



Drainage Challenge in Wales

Contractors seeking a solution to providing a lightweight drainage system for a waterlogged peat bog specified Leca® Lightweight Expanded Clay Aggregate to prevent sinkage and ensure effective drain off.

Site owner, multi-national oil company BP, contracted Andrew Scott Limited, of Margam, Port Talbot to construct the new surface water drain and interceptor at nearby Llandarcy to replace an old, silted V-ditch within its refinery site.

Because traditional materials would have been too heavy and sunk into the bog, an all-round lightweight solution was needed in order to ensure the drain run and interceptor would work effectively, avoiding backflow problems.

Working to a design by URS, of Bristol, Andrew Scott Limited installed 315 linear metres of half-slotted HDPE drainage pipe backfilled with 240m3 of Leca® Lightweight Expanded Clay Aggregate which was then topped with 300mm of mushroom compost.

By using the Leca® Lightweight Expanded Clay Aggregate rounded granules as an infill, the contractors were able to surround the pipelines without any damage and substantially reduce the likelihood of any settlement, which was the major risk had traditional heavy pea gravel been used.

Use of the lightweight Leca® Lightweight Expanded Clay Aggregate fill also meant that adjusting the levels of the pipes during installation was far easier than it would have been had heavy aggregates been used. In addition, because the surface water drain used was half perforated, acting as a filter drain, the system also benefited from the free-drainage properties of Leca® Lightweight Expanded Clay Aggregate.