HDPE Geomembrane Lining for Sustainable Aquaculture Infrastructure

Project overview

The Multipurpose Seaweed Park Project in Valamavur, Tamil Nadu is an aquaculture facility built to support seaweed cultivation on the Tamil Nadu coast. Seaweed farming is promoted by coastal development authorities and marine research bodies for coastal livelihoods and sustainable use of marine resources.

A park like this needs lined ponds and containment areas that hold saline water, nutrient-rich solutions and marine biomass without seepage into the surrounding soil and groundwater. Ocean Non Wovens supplied geomembrane liners for the park’s water bodies and supported their installation.

Materials supplied by Ocean Non Wovens

• Ocean HDPE Liner, 750 Micron: 6,500 SQM
• Ocean HDPE Liner, 1000 Micron: 15,100 SQM

Why a seaweed park needs geomembrane lining

A multipurpose seaweed park combines nursery tanks, cultivation ponds, nutrient circulation zones and water storage reservoirs. The lining in all of them is continuously exposed to:

• Saline and brackish water
• UV radiation in an open coastal setting
• Biological growth and organic matter
• Changing water levels and hydraulic pressure

HDPE liners are widely used in aquaculture because they are effectively impermeable (equivalent hydraulic conductivity of the order of 10⁻¹³ m/s) and unaffected by salt water. Nutrient-rich water stays in the system, so less is lost and less has to be pumped back in.

Coastal soils in Tamil Nadu are often sandy and permeable, so an unlined earthen pond here can lose a large share of its water to seepage over a cultivation cycle. A welded geomembrane removes that loss.

Product selection: 750 micron vs 1000 micron

Two thicknesses of Ocean HDPE Liner were used, matched to the demands of different zones in the park.

Ocean HDPE Liner, 750 Micron

Used in controlled cultivation zones and secondary water channels, where mechanical load and hydrostatic pressure are lower. At 0.75 mm it is flexible enough to follow curved pond profiles closely, resists salt water, and carries carbon-black UV stabilisation for open coastal exposure.

Ocean HDPE Liner, 1000 Micron

Used in primary containment areas, water storage reservoirs and zones with higher water pressure and equipment movement. A 1 mm sheet has higher puncture resistance and tensile strength, holds up better under cyclic loading, and is less likely to be damaged by tools and equipment during operation.

Splitting the area between two grades put the heavier, costlier sheet only where the loads called for it.

Installation details that decide performance

In aquaculture ponds, how the liner is installed matters as much as the material.

Subgrade preparation

The subgrade must be free of sharp stones, roots and debris. A single sharp protrusion can become a puncture point over time under water pressure and movement. The usual practice is a smooth, compacted subgrade and, where the soil cannot be made clean enough, a nonwoven geotextile cushion under the liner.

Thermal expansion and contraction

HDPE expands and contracts noticeably with temperature, and the surface of a black liner on the Tamil Nadu coast is far hotter in the afternoon than at dawn. Liner laid tight in the heat goes into tension when it cools, stressing seams and corners; liner laid with no allowance in the cool forms large wrinkles when it heats. Panels need a measured slack allowance, and seaming and anchoring are best done at moderate temperatures.

Seam welding quality

Seams are a common weak point in lined ponds, alongside punctures from poor subgrade or cover placement. Hot-wedge welding, air-pressure testing of the dual-track seams and visual inspection are standard. On this project, welding parameters were controlled to suit the liner thickness and ambient site conditions.

Maintenance

Even a well-installed liner needs periodic inspection for:

• UV degradation at exposed edges
• Mechanical damage from tools or equipment
• Biofouling build-up at anchor trenches

Catching and repairing these early keeps a small defect from becoming a leak.

Environmental and operational benefits

• Water conservation: near-zero seepage conserves saline and treated water and cuts pumping and refilling.
• Soil and groundwater protection: the liner keeps saline water out of surrounding soil and groundwater, which matters in coastal farming belts.
• Yield control: stable water quality and nutrient retention make seaweed growth cycles more consistent.
• Lower contamination risk: the liner separates the cultivation water from the native soil.

The 750 versus 1000 micron decision here follows a general method. Our article on how to specify geomembrane thickness sets out the factors that decide the grade and whether 500 micron is enough for a pond.

Lessons from the project

Geomembranes have long been used in landfills and reservoirs; Valamavur shows the same geosynthetics serving aquaculture and coastal development. Two lessons carry over to similar projects. First, specify liner thickness zone by zone: using two grades here balanced cost and performance. Second, involve the geosynthetics supplier at design stage, so liner layout, anchoring details and water load calculations are settled before construction starts.

Ocean Non Wovens works with project teams on product selection, application-specific design support and on-site technical guidance for aquaculture, reservoirs, landfills, canals and coastal infrastructure. If you are planning a water containment or lining project, our technical team can help you choose the right grade. Browse more case studies or see Ocean’s pond liners.