Pond lining in Bradford

Lodges, farm reservoirs and wildlife ponds

The worsted mills in the Bradford valleys needed water, and many kept a lodge alongside. A few of those survive as ponds today. New work here ranges wider: hill farms around Oxenhope and Denholme storing water for stock, wildlife ponds on housing schemes, fishing lakes, and garden ponds on larger plots in Wharfedale.

Moorland water has its quirks. It arrives quickly after rain, can carry peat and grit, and drops away in a dry summer. Inlets need protecting from scour, and a margin that dries out each year is where a liner sees most sunlight, which is why the heavier sheets are favoured for farm stores up here.

Which membrane for which pond

We recommend the liner at survey, from the pond's size, shape, bed and purpose:

• EPDM, rubbery and soft, for a modest garden or nature pond
• LLDPE where big welded panels must drape into a lumpy bed
• PP around tricky shapes, inlets and stonework
• HDPE for big reservoirs and banks left open to the weather
• GCL, a clay liner, where a natural bed is wanted (it has its own page)

Wind on an exposed hillside

On open ground towards the moor tops, wind is the enemy of a liner half laid. A loose panel acts like a sail. We deploy in sections, ballast as we go, and only open as much sheet as can be welded and secured in the time available. Welding waits for a clean, dry seam, and a trial weld peeled on site proves the machine settings before the real seams are run.

Underneath, a protective geotextile underlay goes down over the trimmed formation first, because gritstone ground is full of angular stone.

Outlets, edges and the crest trench

Inlets, overflows and any pipes through the liner are formed and sealed as their own details. Round the rim, the sheet turns down into a trench and is backfilled there, which stops it slipping into the pond or lifting in a gale. We go over every seam and detail before leaving and complete the weld log for your file.

Fishing lakes need a little extra thought at the margins, where anglers stand and banks get trampled. A protective layer or stone over the sheet in those spots is worth building in from the start.

If you have an existing pond that is losing water, we can inspect it first. A failed taped joint or a liner laid with no underlay is the usual culprit, and a new welded system over fresh protection is normally the lasting fix.