Water Storage Pond Lining in Port Blair: 1 mm HDPE Liner over 400 GSM PET Geotextile

Port Blair (now Sri Vijaya Puram), in the Andaman and Nicobar Islands, gets heavy monsoon rain, yet much of it runs straight off into the sea. Through the dry months the islands depend on stored water. A storage pond only helps if it holds what it collects, so the lining has to be watertight and built to last.

For this water storage pond, Ocean Non Wovens supplied two products that work as one lining system: 13,500 sq m of 400 GSM PET non-woven geotextile as the protection and cushion layer, and 13,500 sq m of 1000 micron (1 mm) HDPE liner over it as the impermeable barrier.

Project Snapshot

Why Ponds Are Lined with Geosynthetics

Traditional pond linings struggle to stay watertight, especially on difficult ground:

• Clay cracks as it dries and still seeps even when well compacted.
• Concrete and masonry are rigid, so they crack at joints and under settlement.
• Every crack is a leak that is hard to trace and costly to repair.

An HDPE geomembrane replaces all of that with a continuous, effectively impermeable sheet that installs quickly over almost any prepared surface. A liner is only as safe as the ground beneath it, so it is paired with a protective geotextile. On a remote island site, that combination gives a lining that is both watertight and durable.

How the Geotextile and HDPE Liner Work Together

Each layer covers the other’s weakness.

The geotextile protects and the geomembrane seals. Under the weight of stored water, stones, roots and sharp edges in the subgrade can stress even a 1000 micron liner. The 400 GSM geotextile spreads those point loads so the liner stays intact for the life of the pond.

Ocean Non Wovens makes both products, so it supplies the liner and the geotextile as a matched pair, with grades chosen for the ponding depth and the subgrade.

Why a 1000 Micron Liner and 400 GSM Geotextile

This project used thicker, heavier grades than a typical shallow farm pond:

• Remote location: on an island, any repair is slow and expensive, so a tougher lining lowers the risk of failure and a repair callout.
• Greater durability: a 1000 micron liner has higher puncture and tear resistance and a longer service life.
• Stronger protection: a 400 GSM geotextile is a heavy cushion against a rough subgrade.
• Demanding environment: heavy rainfall, coastal air and seismic activity all favour a tougher, more forgiving lining.

Product Specifications

Ocean HDPE Liner, 1000 micron

Ocean Non-Woven Geotextile (PET), 400 GSM

HDPE Liner vs Clay or Concrete Lining

On a remote island, the case against bulk clay and concrete is even stronger than on the mainland.

Shipping thousands of tonnes of clay or concrete to an island is costly and slow. A geosynthetic lining arrives as compact rolls.

Engineering Challenges at Port Blair

The island setting shaped the design in several ways:

• Remoteness: materials are shipped in and repairs are difficult, so reliability comes first.
• Heavy monsoon rainfall: the pond fills fast and the surrounding ground stays saturated.
• Seismic activity: the Andaman region lies in India’s highest seismic zone, so the lining must tolerate ground movement.
• Coastal exposure: salt-laden air and possible brackish conditions call for strong chemical resistance.
• Uneven subgrade: stones and sharp fragments put the liner at risk of puncture.
• Intense sun: strong ultraviolet radiation attacks any uncovered liner.

How the Lining System Performs

• Seepage control: the 1000 micron liner is a continuous impermeable barrier that stops almost all downward loss of stored water.
• Containment: the water is held against the ground instead of draining into it.
• Puncture protection: the 400 GSM geotextile spreads point loads so the liner is not pierced.
• Seismic tolerance: the flexible liner stretches with ground movement instead of cracking.
• Slope and erosion protection: the lining shields the water-facing slopes from wave action and changing water levels.

The pond keeps its fresh water through the dry season, which on an island goes straight to water security.

The Technical Basis

Three mechanisms explain why the system works.

Impermeability. HDPE is dense enough that seepage through an intact, properly welded sheet is negligible.

Puncture protection. The heavy geotextile absorbs concentrated stresses from the subgrade, a property tied to its puncture resistance (ASTM D4833) and grab tensile strength (ASTM D4632).

Hydrostatic containment. The anchored liner resists the pressure of the stored water column. It stretches a long way before failure, so it absorbs settlement and seismic movement without tearing.

Turning many panels into one continuous barrier depends on sound seaming. Welds are made under controlled conditions and tested by air-pressure and vacuum-box methods, in line with GRI and IS practice.

Installation Sequence

A lining system only performs if it is installed correctly. The main steps:

1. Prepare the subgrade: trim, compact and clear the bed and slopes of stones and sharp debris.
2. Lay the geotextile: roll out the 400 GSM PET fabric across the bed and slopes with the specified overlaps.
3. Deploy the liner: roll out the 1000 micron HDPE panels over the geotextile, positioned to minimise field seams.
4. Weld and test: join the panels by hot-wedge and extrusion welding, then test every seam.
5. Anchor and secure: fix the lining in a perimeter anchor trench, ballast it against wind, and leave slack for thermal and seismic movement.

Common mistakes to avoid:

• Leaving sharp points in a poorly prepared subgrade
• Under-lapping or skipping the geotextile
• Weak or untested welds
• Leaving the lining exposed to the sun for too long

Ocean Non Wovens helps customers match the liner and geotextile grades to the subgrade and ponding depth so the installed system performs as designed.

Long-Term Performance

The system is built for decades of service:

• UV resistance: the liner is carbon-black stabilised against strong island sun.
• Stress-crack resistance: tested to ASTM D5397, it resists the slow crack growth that ends the life of lesser polyethylenes.
• Chemical resistance: unaffected by the salts and coastal chemistry the pond is exposed to.
• Cyclic and seismic durability: it holds up under repeated wetting, drying, thermal cycles and ground movement.
• Low maintenance: with no moving parts, the system needs only occasional inspection.
• Lifecycle savings: a thin section, fast installation and long life cost far less over time than clay or concrete, especially where repairs are hard to reach.

Sustainability Benefits

• Water conservation: by preventing seepage, the lining saves scarce fresh water, the most valuable outcome on an island.
• Lower transport carbon: light rolls replace thousands of tonnes of clay or concrete that would otherwise be shipped in.
• Faster construction: a shorter build window on a remote site.
• Longer life: fewer rehabilitation cycles over the pond’s lifetime.
• Rainwater harvesting: a lined pond captures and keeps monsoon rain that would otherwise run off to sea.

Where This Lining System Is Used

The same geotextile and HDPE liner combination suits a wide range of water and containment works:

• Drinking and raw water reservoirs
• Rainwater harvesting structures
• Irrigation and farm ponds
• Canals and channels
• Aquaculture ponds
• Effluent and sewage lagoons
• Industrial process ponds
• Landfill barrier layers

Frequently Asked Questions

What liner thickness was used for the Port Blair pond?

A 1000 micron (1 mm) HDPE liner, laid over a 400 GSM PET non-woven geotextile. Both products covered 13,500 sq m.

Why put a geotextile under an HDPE pond liner?

The geotextile cushions the liner against stones and sharp points in the subgrade and spreads the load of the stored water, so the liner is not punctured.

Is an HDPE liner better than clay or concrete for a pond?

For seepage control, yes. Clay seeps and cracks as it dries, and concrete cracks at joints and under settlement. A welded HDPE liner is effectively watertight and flexes with ground movement.

Why use a thicker liner on an island project?

Repairs on an island are slow and expensive, and the Andaman region is highly seismic. A 1000 micron liner gives more puncture and tear resistance and a longer service life, which lowers the risk of a failure that is hard to reach.

Partner With Ocean Non Wovens

Ocean Non Wovens supplied 13,500 sq m each of geotextile and HDPE liner to this Port Blair pond. The company manufactures HDPE liners, non-woven and woven geotextiles, geocells, geogrids and geobags in India, tested to Indian and international specifications, and delivers them at the volumes and timelines that large and logistically demanding projects need. Its materials go into water resources and environmental works, irrigation and pond lining, highways, railways, industrial developments, airports and defence infrastructure across India and its islands.

For pond and reservoir lining, seepage control, protection, reinforcement or containment, Ocean Non Wovens can recommend and supply the right liner and geotextile grades for your site conditions. Talk to the Ocean team about your next project.