Frequently Asked Questions About Dam Liners
DURADAM Dam liners are a reliable and permanent method to stop leaks and water seepage in dams. Below are common questions asked about our DURADAM product and dam liners in general. If you don't find your answer here, please feel free to contact us with your questions, we are only too happy to answer.
Rural Dam Liners
Liners for use in dams in rural and farming situations.
Yes, nearly all plastic based liners do not decay just from being submerged in water. PE and rubber based liners are well suited to dam lining applications and have been known to last 40 years or more (for rubber). Breakdown of a liner will usually occur for two reasons:
- UV degradation of the liner
- Damaged from poorly prepared surfaces, causing holes or tears in the liner
Where a dam is a source of drinking water for farm or wild animals great care must be taken to protect the liner. This can be achieved in one of two ways:
- Placing at a geotextile and at least 300 mm of gravel over the liner, so that animal hooves etc don't come into direct contact, damaging the liner. However this must be carefully done as it can be easy for some animals to sink through wet soil to the liner below, damaging it.
- A more permanent and safer approach would be to fence off the dam, adding in piping that takes the water to troughs.
The short answer is yes. Repair will depend on the type of liner you have, but typically involves cleaning the affected area and applying a patch.
There are a number of things you can do during installation and over the lifetime of the liner to make sure it lasts the longest possible:
- Quality PE liners can last around 10 years, but will still eventually succumb to UV degradation. To minimise UV exposure you can cover the dam liner with at least 300 mm of soil, either at least 300 mm below the water line mark, or entirely. A covered liner will receive a lot less UV exposure, greatly extending the serviceable lifespan of the liner.
- Do not let animals directly walk on the liner. Animal feet loves, claws etc all have the potential to scratch and tear the liner and should be avoided. If animals are a problem, either fence off the dam or cover with soil.
- Ensure there are no rocks, stones, roots or sharp objects underneath the liner. Where there is the potential for hazards, we recommend the use of a geotextile underlay.
To make sure you order just the right amount of dam liner material it is important to consider two important factors. You will need to work out how much liner you will use for the edging and trench along each side, and you will also need to know the slope of the dam walls.
This is because the deeper your dam and the steeper your dam walls, the wider the edging needs to be. When asking for a quote, always confirm the amount of edging that has been allowed in the making of the liner. Too little and you won't be able to anchor the dam liner properly. Too much and you will pay too much for the liner and waste un-needed material.
We have made a separate page to help you work out how much dam liner material you will need and can be view here
The amount of edging you require will depend on the design of your dam. We recommend at least 1 metre extra liner all round, giving you enough liner for a trench that is 500 mm from the edge of the dam. The actual amount required will depend on your dam design and we recommend seeking professional advice first.
Sometimes it is possible to see parts of the liner floating up. This generally occurs for one of 3 reasons:
- There is a rising water table underneath the dam
- There is rising water from a nearby spring
- There may be gas being given off from buried vegetation under the dam
Depending on your needs, there is a range of liner materials to suit your application and budget. Polypropylene (PP) and Polyethylene (PE) are the most common types of liners, but butyl rubber ones are sometimes used.
- PVC was once a common usage for large dams, but not so any more, with PE being a better choice. It is too costly and doesn't offer a long life expectancy. It is still suitable for smaller installs though.
- A quality PE liner can provide for a long life expectancy, and
- EPDM and butyl based rubber liners tend to give the longest lifespans, with 30+ yrs not being uncommon.
A dam liner can be supplied in a range of thicknesses. Generally the thicker the material the longer lasting it will be. The cheaper liners start at around 200 micron, but much lower UV resistance generally only last a few years even if buried. For long term dams, it can be more economical to look at a thicker liner that has a much greater expectancy.
At the budget end of choices are tarpaulin based dam liners. Will the reinforcement will be of benefit, the overall thickness is still around a third of straight film liners and hence are generally not long lasting (2 to 5 years). So in applications where longevity is required, they are not recommended.
A dam liner is an impermeable geomembrane material that is installed over the surface of a dam, preventing leakage. This means unlike most sealants used, a dam liner is a permanent prevention against dam leakage as well as stopping water table contamination.
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