Benefits of Using Plastic Lined Ponds for Water Storage

In regions where rainfall is seasonal and unpredictable, storing water between rain events is not a luxury – it is a survival strategy for farmers. Traditional earthen ponds have long been used for this purpose, but they come with a critical flaw: they leak. According to Tamil Nadu Agricultural University, an estimated 70% of stored water is lost between the point of storage and the point of use, primarily due to seepage through porous or sandy soils. Plastic-lined ponds directly address this problem. By placing a high-quality plastic film across the floor and walls of an earthen pond, water is retained far more effectively – making these structures a practical and affordable solution for agriculture in water-scarce areas.

What is a plastic-lined pond? 🔗

A plastic-lined pond is essentially a dug-out earthen pond whose interior surfaces – the base and sides – are covered with an impermeable plastic film. This film acts as a physical barrier between the stored water and the surrounding soil, preventing seepage. The pond is then typically filled with rainwater runoff or water diverted from seasonal streams.

The plastic film most commonly used is Low-Density Polyethylene (LDPE), available in thicknesses ranging from 100 to 250 microns. TNAU’s technical guidelines specify that the film should meet Indian Standard specifications for mechanical properties, including tensile strength, elongation at break, and carbon black content for UV resistance. For deeper ponds (over 3 metres), a thicker film of 250-300 microns is recommended. The film is usually black in colour, which helps prevent weed growth beneath the liner and provides some UV protection.

Other materials also used in lining include High-Density Polyethylene (HDPE) and Polyvinyl Chloride (PVC). HDPE liners in particular offer a lifespan of 20-50 years, while PVC typically lasts 10-20 years. The choice of material depends on the farm’s budget, soil conditions, and anticipated pond depth.

The seepage problem in earthen ponds 🔗

To appreciate why plastic lining matters, it helps to understand how serious seepage losses actually are. Data from TNAU shows that in loose sandy soils, seepage causes water levels to drop by over 50 cm per day, and in porous gravelly soils, a pond holding water at 4 metres depth can completely empty within just five days. Even in moderately permeable soils, daily losses of 5-15 cm are common.

These losses are not just about water quantity. Seepage can also cause waterlogging in adjacent fields, destabilise pond embankments, and increase soil salinity in surrounding areas – all of which create additional problems for farmers. Plastic lining tackles this at the source.

Key benefits of using plastic-lined ponds 🔗

Dramatic reduction in seepage loss 🔗

The most direct benefit is water retention. As documented by the National Centre for Plastics in Agriculture (NCPAH), plastic film lining can reduce seepage losses by up to 100%, while TNAU reports a seepage reduction of up to 95%. In practical terms, this means that water collected during the monsoon can be held for weeks or months longer than in an unlined pond – enough time to provide supplemental irrigation during dry spells within the same growing season, or even into the following season.

Reliable water supply for irrigation and other uses 🔗

NCPAH notes that plastic-lined ponds serve multiple purposes: supplementary irrigation, pisciculture (fish farming), livestock watering, and domestic use. A large number of ponds have been lined with plastics specifically for providing drinking water in the coastal and hilly areas of Gujarat, West Bengal, Karnataka, Himachal Pradesh, and Uttarakhand – areas where surface water sources are either seasonal or unreliable.

For rainfed farming, the significance of this stored water is profound. Research published under the All India Coordinated Research Project for Dryland Agriculture confirms that farm ponds enable farmers to provide life-saving irrigation at critical crop growth stages – such as flowering and grain filling – when a dry spell without intervention would otherwise cause complete crop failure.

Suitability for porous and gravelly soils 🔗

Plastic-lined ponds are particularly suited to areas where the soil is gravelly and porous, where conventional unlined ponds are essentially ineffective. In such soils, even clay lining provides limited protection – clay becomes increasingly permeable over time, especially as it dries and cracks between water storage cycles. Flexible plastic films, by contrast, maintain their impermeability regardless of the soil type underneath.

ICAR-CIARI’s work in the Andaman and Nicobar Islands demonstrates this clearly: in sandy coastal soils where unlined ponds dry up entirely in the post-monsoon period, plastic-lined ponds have enabled year-round water availability for vegetable cultivation and domestic use.

Prevention of waterlogging and salt intrusion 🔗

Beyond water retention, plastic lining performs another important function: it acts as a two-way barrier. According to NCPAH, lining eliminates waterlogging in the surrounding soil and prevents the upward intrusion of salts into stored water. This is especially valuable in areas with saline or sodic soils, where rising salts can contaminate the pond water and make it unsuitable for irrigation or drinking.

Better water quality 🔗

Because the plastic film creates a clean separation between the stored water and the soil, lined ponds tend to maintain better water quality. As Agriplast notes, the barrier keeps soil particles, contaminants, and soil-borne pathogens from mixing with the stored water. This matters both for crops – which are sensitive to soil-borne diseases spread through irrigation water – and for livestock that drink from the pond.

Cost-effectiveness compared to alternatives 🔗

Conventional lining methods such as brick masonry, precast concrete tiles, and stone slabs are either too expensive for small farmers or insufficiently watertight. TNAU’s assessment is that LDPE film lining, particularly with a compacted soil or thin concrete cover over the film, offers an economical and effective alternative. The film itself is lightweight and available in wide rolls (4 to 10 metres), which simplifies transportation to remote farms. Industry data indicates that HDPE liners can reduce maintenance costs by 20-30% compared to traditional materials.

Construction and installation essentials 🔗

Getting the installation right is critical to performance. TNAU’s technical guidelines outline the following key steps for constructing a plastic-lined pond:

• Site preparation: The pond is excavated to the required dimensions. All stones, sharp gravel, and plant roots must be carefully removed from the excavated soil before it is used as cover material. Any sharp object left in contact with the film is a potential puncture point.
• Film laying: The plastic film is unrolled in strips over the prepared subgrade, laid loosely – not stretched tight – to allow for thermal expansion and contraction during the day. An extra 1% length in both directions is typically provided for this.
• Jointing: Where two strips of film meet, the joint must be sealed properly. Heat sealing (using an iron at approximately 150°C) is considered the most effective jointing method. Other options include folded overlaps, bitumen jointing, and adhesive tape.
• Top cover: The film is covered with a protective layer – either compacted soil (minimum 7.5 cm, free of gravel), precast concrete tiles, brick, or stone slabs – to protect it from physical damage and UV exposure. The choice of cover also determines the recommended film thickness.

The challenge of wetting and drying cycles 🔗

One of the most significant operational challenges for plastic-lined ponds in rainfed regions is the repeated cycle of filling and drying that occurs with seasonal rainfall patterns. When a pond fills during the monsoon and then gradually empties during the dry season, the exposed plastic film – particularly the upper portions of the side slopes – undergoes alternating wet and dry conditions.

These repeated wetting-drying cycles, combined with UV radiation from direct sunlight, degrade the polymer chains in the film, making it brittle over time. The degradation typically begins with discolouration, progresses to surface stiffness, and eventually results in cracking – particularly along fold lines and at stress points near the edges and anchoring trenches.

UV damage manifests first as fading or discolouration in sun-exposed areas, then as brittleness and surface cracks that eventually allow water to seep through. If not addressed early, these cracks extend and compromise the integrity of the entire lining.

Preventing and managing liner degradation 🔗

Several precautions help extend the life of a plastic-lined pond and reduce the risk of cracking from wetting and drying:

• Choose UV-stabilised film: Quality LDPE and HDPE films contain carbon black (typically 2.5-3%) as a UV stabiliser. TNAU’s specifications require uniform dispersion of carbon black in the film matrix to ensure consistent UV protection. Reprocessed LDPE film – which cannot guarantee these properties – should never be used.
• Cover exposed sections: Portions of the liner that are frequently exposed to sun as water levels drop should be protected with soil cover, stone, or shade structures where feasible.
• Do not leave film rolls exposed: Unpacked film rolls should not be left exposed to sunlight for prolonged periods before use. They should be stored indoors in original packaging.
• Conduct regular inspections: Seasonal inspections – particularly in spring and autumn – should check for signs of discolouration, surface cracks, or areas where the liner feels brittle. Temperature changes between seasons cause the liner to expand and contract, which can reveal hidden weak spots.
• Repair early: Small cracks and punctures can be repaired using compatible adhesive patches or heat-sealed liner pieces. If early signs of UV damage are spotted, applying a UV-protective coating can prevent further deterioration. Extensive damage, however, may require section replacement or a full re-lining.

Where plastic-lined ponds make the most difference 🔗

In India, approximately 25 lakh ponds are used across states like Andhra Pradesh, Karnataka, Tamil Nadu, Odisha, and Madhya Pradesh. The seepage losses in some of these pond-containing soil types can reach 11 m³/s per million square metres of wetted area – a staggering loss rate that makes unlined storage practically futile in those regions.

Plastic-lined ponds are particularly effective in three situations: where soils are gravelly or porous; where water availability is intermittent and limited to a short monsoon window; and where farmers need to store water for supplemental irrigation of short-duration crops during dry spells. Research from ICAR’s All India Coordinated Research Project for Dryland Agriculture confirms that farm ponds integrated with supplemental irrigation can significantly improve crop yields and stabilise production across rainfed agroecologies. The technology has been incorporated into national programmes including PMKSY (Pradhan Mantri Krishi Sinchayee Yojana) and MGNREGA-funded water conservation projects.

Ultimately, a well-constructed and properly maintained plastic-lined pond is not just a water storage structure – it is a buffer against the uncertainty that defines rainfed farming. By keeping more of the monsoon’s gift in the field rather than letting it disappear underground, these ponds give farmers a fighting chance during dry spells that would otherwise wipe out entire harvests.

What do you think? Given that seepage losses can drain an unlined pond in as little as five days in certain soils, is lining every farm pond a practical priority for rainfed agriculture in your region? And with the challenge of UV-induced cracking from repeated wetting and drying, what low-cost solutions do you think could help small farmers extend the life of their pond liners?

References

1. https://agritech.tnau.ac.in/agricultural_engineering/farmpond_reservoir.pdf
2. https://www.bpmgeosynthetics.com/what-is-plastic-pond-liner-and-its-applications/
3. https://www.ncpahindia.com/pond-lining
4. https://www.researchgate.net/publication/366848318_Farm_pond_Resilient_technology_for_higher_productivity_in_rainfed_farming
5. https://www.thepharmajournal.com/archives/2022/vol11issue2S/PartK/S-11-1-222-514.pdf
6. https://ciari.icar.gov.in/FC-waterharvest.html
7. https://www.agriplast.co.in/blogs/how-pond-liners-ensure-reliable-water-storage-for-irrigation
8. https://westernliner.com/blog/what-are-the-common-causes-of-damage-to-pond-liners/
9. https://www.btlliners.com/troubleshooting-common-issues-with-pond-liners
10. https://www.btlliners.com/repairing-and-maintaining-pond-liners
11. https://epubs.icar.org.in/index.php/IndFarm/article/view/131369