Canal Work Project – IGI Airport Delhi Case Study

Ocean Global supplied 4000 sq m of 1.0 mm geomembrane to line a canal in the area around IGI Airport, New Delhi. The liner’s job is to stop water seeping out through the canal bed and banks.

Product: Ocean Geomembrane-1.0mm

Quantity: 4000sqmtr

Location: IGI Airport, New Delhi

Why canals need lining

Canals are artificial channels that carry water for irrigation, drainage, water supply and, on larger waterways, navigation. In India, canals are the second-largest source of irrigation after wells and tube wells.

An unlined canal loses water through its bed and banks before it reaches the end user. Traditional canal lining falls into two groups: earthen linings (compacted earth or soil cement) and hard linings (brick, boulder or concrete).

Problem

Each traditional option has a weakness. Earthen canals are cheap to build but lose a large share of their flow to seepage, erode, and get choked by weeds, so their capacity drops over time. Concrete linings resist erosion and vegetation but cost more and crack with settlement, shrinkage and temperature cycles. Every crack becomes a leak, so a concrete-lined canal can still lose significant water unless it is repaired often.

Solution

A geomembrane provides a continuous impermeable layer under the canal section. It can be used on its own or under a concrete cover. When used under concrete, the membrane keeps sealing the canal even after the concrete cracks, until the cracks are repaired. A nonwoven geotextile under the geomembrane cushions it against stones and uneven subgrade, and a geogrid can be added where the subgrade is weak.

Geomembrane canal liners can be left exposed or covered. Most are UV-stabilised and can stay exposed for long periods, but an exposed liner is open to damage from rocks, debris, equipment, animals and vandalism. For that reason most lined canals get a protective cover: cast-in-place reinforced concrete, concrete pumped into geotextile forms, precast panels, sprayed concrete, or at minimum a layer of earth ballast.

Geomembranes also suit rehabilitation. They can be laid over an existing earthen or cracked concrete canal, and the worst-leaking stretches can be relined first when the budget doesn’t cover the whole length.

On this project around IGI Airport, Ocean Global supplied 1.0 mm geomembrane to line the canal and cut seepage losses.

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