Pond lining in Worcestershire

A 3,500m² basin in Worcester

The biggest pond we have lined in the county is a 3,500m² basin in Worcester, built to hold back runoff from roughly 50 houses. It was lined in 1mm HDPE between two layers of 300g/m² fleece and welded panel to panel across the full area. HDPE rolls of that width are heavy, so the deployment was planned around specialist lifting gear that put each section down without dragging or creasing it.

Open basins like this one are a common part of drainage strategies on Worcestershire estates. They hold runoff from the homes and let it go at the rate the engineer sets, and the welded lining keeps that water exactly where the design expects it to be.

Picking the sheet

What the pond is for, and the ground it sits in, decide the liner. On the sandstone around Kidderminster and Bromsgrove an unlined pond simply drains. On the mudstone further south it may hold for a while, but seldom reliably enough for a reservoir or a stocked lake.

• HDPE for big reservoirs and basins with long exposed banks
• LLDPE where the sheet has to follow an uneven formation
• EPDM for smaller garden and wildlife ponds
• PP for awkward shapes and detailing around structures
• GCL for gentle, soil-covered ponds with suitable water

Irrigation, angling and amenity water

In the Vale of Evesham, growers collect water through the winter for use on summer crops, and a lined reservoir keeps every cubic metre they gather. Along the Severn and the Teme, fishing lakes and estate ponds need a liner that is safe for stock and will last decades under water. Golf courses and country houses across the county add ornamental lakes and water features.

On the flat land of the Vale, a reservoir is often built partly in embankment, so the volume comes from raised banks rather than a deep dig into wet ground. The liner then runs up the inside face and over the crest into its trench, the same detail as a pond dug wholly below ground.

What happens on site

Shaping the hole is the earthworks contractor's part. Ours starts on the trimmed bed: a geotextile cushion first, then the membrane rolled out and joined by wedge or extrusion welder, with one trial weld logged for the file. Outfall pipes and overflows are booted and sealed, the top edge is buried in a trench round the rim, and the weld log is yours when we pack up.