Dam liner is thin water proof geomembrane that is used for the retention of liquids. It is used specifically in the lining of not only dams, fishponds, water reservoirs, garden ponds but also in hazardous and nonhazardous surface. They often offer simple ways of providing waterproofing and lining of water pans and ponds where the soil is too porous. Dam liners are also mostly applicable in the design of water harvesting structures used  in irrigation, drinking, and fish farming or any domestic purposes.

Characteristics of a good dam liner that a farmer may consider.

Dam liners have various characteristics that make them suitable to be used in various water projects and infrastructures. These characteristics vary depending on the type and dimensions based on the different manufactures. Furthermore, water projects structures including dams and ponds require the very best liner materials to prevent puncturing and leakage from the reservoir to increase their life span.

Dam liners should be able to last longer and have a span of about 25 years. It should be resistant to excess ultra violet radiation and UV treated in order to increase its durability, flexibility, and longevity depending on the thickness .

the liner should also be made from original materials so as to make it long-lasting since the virgin materials have not been affected by the weather elements.

Materials that are used to manufacture dam liners should be of high resistance to abrasion, puncturing, cracking, low temperature, corrosion, and should have a large temperature range.

They should be cheap, affordable, and friendly to the farmer, in terms of type of material, thickness, size of the dam among other features.


Types of dam liners sold in Kenya.

Majorly four types of dam liners are sold in the Kenyan market.

1.    Ethylene propylene diene monomer (EPDM) Liners

EPDM is a type of rubber dam liner that is mostly used in small and medium decorated ponds. It is very much flexible and easily bendable and can be bent into different shapes and corners. EPDM is very easy to puncture or tear with heavy, weighty, and difficult to pull abilities and it does not come into wide length. Its life expectancy can be about 20-30 years. This type of liner is thick enough that it can be challenging to fold the liner to fit into the pond’s cavity.


  1. Reinforced Polyethylene liners

Reinforced polyethylene liners are lighter in weight as compared to EPDM . They are one of the longest-lasting liners available in the current market, with a life span of up to 40 years, and are highly puncture resistant. They are stronger than other types of liners . They are higher and made with thicker material. The RPE liners are a good choice for large ponds because they are sold as large panels of approximately 60,000 square feet. The materials used to make them are cheap and cost-effective.

  1. Butyl polypropylene Liners (Hdpe liners).

These are box welded polypropylene synthetic rubber liners. The content in the material makes the material easy to fit into irregularly shaped ponds with many nooks and crannies. They are preformed and can be made into different shapes including 3-D shaped liners that are heat welded into rectangular and cylindrical shapes using flexible polypropylene liners. BPL is mainly used in informal ponds applications where clean liners are in demand. There is no need to fold them into different shapes. They have a life expectancy of approximately 25 years.

  1. Polyvinyl Chloride plastic liners(PVC Liners)

The Polyvinyl chloride liners are the most cheaper, durable, and flexible pond liners that are commonly used by most people in Kenya. They are readily available in the market stores in a variety of widths and thicknesses. These types of liners do not have ultraviolet protection therefore any portion of the liner is exposed to the sun.


Design specification of dam liners materials.

Most of dam liners are manufactured depending on the volume of water it is holds, thickness, solar intensity, length and the surface type. These factors depend on the various sizes of the gauge of the liners.

  • 300 microns (0.3mm) gauge

These types of liners are mainly used in smooth surfaces where there are no sharp objects. Severally used on small dams, with a specific length of 100meters and a width of up to 15meters. These liners are commonly welded together to fit the size of the dam. These make of liners have got a lifespan of approximately 10 to 20 years . They are ultraviolet treated thus can last longer. They are sold as black in color.

  • 500 microns (0.5mm) gauge

These liners are applied in light surfaces, where there are no sharp objects. Normally applicable in medium dams. Often sold at a length of 200meters and width of 6 or 8 meters. Apparently, it can be also welded together into different shapes and designs. Their lifespan ranges between 10 – 15 years. Are black in color? They are also ultraviolet treated to ensure a longer lifespan thus have chemical and light resistance.

  • 750microns (0.75 mm) gauge

The liners of these gauges are applicable for the medium to large projects. Usually sold in lengths of 150 meters and width 8 meters and are black in color. They can be welded and joined together into different shapes and designs. They are also ultraviolet treated thus longer lifespan of about 15-20 years.

  • 1000 microns (1mm) gauge

These are a type of dam liners of greater thickness. mostly applied in large projects with rough surfaces, rocky or stony. Commonly retailed at a specific length of 120 meters and width of 8 meters. Characterized with a longer life span of between 20 – 30 years. They are ultraviolet treated hence can last longer.

Preparation of the dam site for installation of dam liner.

There are certain preparations that must be done on the site where the dam liner is to be installed, before placing, unfolding, and installing the dam liner. Kindly ensure that:

  • The site is cleared and all roots, stumps logs, boulders, rocks, outcrops, all vegetation, organic matter, loose clods, surface debris, mud, waterlogged ground, and water are removed.
  • The surface is compacted by rollers or vibrators to a finished grade level.
  • The surface is leveled to a uniform texture not exceed that of graded aggregate.
  • The graded surfaces are sand blinded to a particle size not exceeding that of course sand to a thickness of 5 mm.
  • The geotextile  protection underlay should be placed to cushion and protect dam liner from damage by sharp objects as well as elevate puncture, impact, and abrasion resistance
  • Ensure that there is free drainage to all surfaces in contact with liner membrane, and the dam liner should not be installed in areas subject to flooding, tides, springs and thermal activity.


Installation procedure guide for dam liner.


  • Trench excavation. Dig or excavate a continuous perimeter trench on a stable berm all-round the dam site using a trench digger. The trench should be far enough from the edge of the berm to provide adequate anchorage. Backfill the trench at a height of 500mm over the buried liner.
  • Establishment of protrusions and venting. After establishing the trenches, dam liner penetrations should be subjected to designed requirements for easy operational purposes. The approved foundations, footings, pads, should be installed to allow for better stability at penetration positions. The sealing of the protruded structural or service elements to the liner membrane should be provided by an appropriate means to minimize liner stress.
  • Lay the unpacked liner at position on berm level ground and unroll to its full length at pond perimeter.
  • Then make the lower liner loose edge into the perimeter anchor trench allowing ample material to be secured to the full width and depth.
  • Using temporary sandbags hold the dam liner edge down intermittently along the trench at its anchor position.

Installation procedure guide for dam liner continuation

  • Depending on the stability of the trench wall, the material should be carried across the lining area by two separate installation crews each carrying half the total weight of the liner. Extend the liner from its folded end to the opposite perimeter trench while allowing ample liner to relax into its final position.
  • By pulling or tugging at the liner after it has settled on the pond/dam bed as friction against the ground of a large liner area can be difficult to overcome. This can only be avoided by taking proper precaution before beginning the installation process.
  • Finally, before the end of installation notes that when the liner has been loose laid with evenly distributed surface ripple, place all surplus liner material into the perimeter anchor trench, allowing ample liner on the pond/dam bed to avoid stretching from the ground settlement after filling.


Problems associated with the leakage of a dam liner.

Dam liners are faced with various challenges that may make them to crack and begin leaking. Some of these challenges may be environmental caused or human caused .They includes:

  • Poor choice of construction materials.
  • The internal soil erosion or piping
  • The cracking of the liner caused by changes to water levels
  • The presence topsoil and vegetation at the embankment site
  • Presence of an unsuitable soil type in the dam wall
  • The absence of a cut-off trench
  • Presence of uncompact soils techniques.
  • The presence of rock and gravel at the basement of the liner.
  • Presence of sand in the storage basin
  • The damage caused by animals and insects.
  • Presence of slumping cracks along the length of the wall due to a combination of poor compaction, excessive seepage and excessive steepness of bank
  • Poor site location for the dam installation.
  • Failure of dam liner due to longer lifespan.
  • Presence of trees on dam bank thus causing loss of storage volume due to uptake for self-watering.

Advantages of a dam liner to the farmer.

  • Most of dam liners are resistance to chemicals especially High-density polyethylene liners, thus there is no threat for hazardous waste.
  • Dam liners have low-permeability rate hence can retain water for many years.
  • They are safe and secure from water penetrations, and also it resists rainwater to seep into the dam liners.
  • They are ultraviolet-resistant and therefore are not easily damaged by environmental stress.
  • Most dam liners are cost-effective hence can easily be afforded by many poor farmers.
  • Available in a variety of shapes and sizes
  • Very easy to seal.
  • Usually light in weight hence easy to carry.
  • Are easily customized according to the purpose they portray.
  • Easy to clean and maintain.
  • Most of dam liners are highly durable and flexible.
  • Can mostly be designed into any required shape depending on the nature of the dam.
  • relatively  easy and very fast to install.

Disadvantages of a dam liner to the farmer.

Dam liners have got various limitations to the farmers, especially to the poor small scale farmers .This is due to expensive cost of maintenance and installation and the nature of the dam liners.

  • Some of the dam liners are hard to conceal thus becomes deteriorated faster.
  • They are manufactured and sold with limited shapes and sizes so the farmer’s preferences cannot be satisfied.
  • Most of these dam liners are costly in terms of cost, maintenance and transportation and hence most farmers are unable to afford them.
  • They are hard to design especially for marshland and borderline plants.