Water Containment Systems

You see water containment systems everywhere today – aquaculture, agricultural reservoirs and ponds to mining, wastewater lagoons to municipal potable water storage projects. Longterm success depends greatly on preventing leakage and protecting surrounding soil and groundwater. This is where geomembrane liners come in.

What is a geomembrane? This is a low-permeability synthetic membrane placed where fluid migration is to be controlled for any number of engineering projects. Due to their excellent in service waterproof performance, HDPE geomembranes and LLDPE geomembranes have become some of the most common lining materials for modern water containment systems.

Compared to a traditional clay liner or concrete, geomembrane liners are much easier to install, are much more economical for large areas, and have substantial chemical and UV resistance.

Today geomembrane water containing liner systems are routinely installed in applications including:

• Agriculture (Aquaculture ponds)
• Landfill leachate ponds
• Mining process ponds
• Wastewater lagoons
• Biogas digesters
• Firewater reservoirs
• Decorative lakes and artificial ponds

Proper selection of the correct geomembrane liner can greatly improve water retention performance and reduce longterm costs.

Key Explanation

What Is a Geomembrane?

An impermeable synthetic liner such as manufactured from polymeric materials including:

• HDPE (High-Density Polyethylene)
• LLDPE (Linear Low-Density Polyethylene)
• PVC
• EPDM

While geomembranes of all these materials may be found (PVC, EPDM, etc. both common in municipal projects), this interfaces with HDPE geomembrane and LLDPE geomembrane is the prevailing geomembrane in number water containing application.

These geomembranes can be delivered smooth, or textured per project specification.

Smooth Geomembrane

Uses for smooth geomembrane include (but are not limited to):

• Water reservoirs and fish ponds
• Wastewater lagoons
• Agricultural irrigation ponds

Being smooth in surface, they are less likely to hold dirt and algae and hence can be easily cleaned.

Textured Geomembrane

Textured geomembrane with increased grounding friction can be useful for use on slopes.

Applications for this geomembrane include:

• Landfills side slopes
• Mining heap leach pads
• Steep reservoir embankments

How It Works In Confining Water

How does the geomembrane “act” on confining water (or any other liquid) so that it does not leak?

The water does not leak out to the nearby earth, and conversely, the groundwater does not leak through the liner to lose out to the incoming water as well as cause soil erosion underneath.

Usually, once you weld two panels to one another, you’ve basically created a continuous curtain system which is impermeable to whatever water or chemicals you are storing for basically going nowhere for years.

For geomembranes today, the installation specification will usually contain sections on such things as:

• Subgrade preparation
• Seam welding procedures
• Vacuum testing
• Air pressure testing
• Anchor trench design
• Protective geotextile placement

The quality of the installation should be as important as making quality components for use.

Applications / Use Cases

Aquaculture Pond Liners

Liners for aquaculture ponds are now becoming popular in the world.

One can utilize HDPE pond liners that:

• Minimize water losses
• Restrict unwanted soil to come into water (and vice versa)
• Produce a clearer pond that is much easier to maintain that way
• Minimize disease risk and maintenance

In the way of usage around our planet, you have:

• Shrimp farming ponds
• Fish ponds
• Tilapia ponds
• Intensive farming systems

In hot climate areas, one that puts a pond in with UV, you would never want to forget to obtain a UV resistant pond liner.

Agricultural Reservoirs

Geomembrane-lined irrigation ponds help farmers to:

• Collect rainwater
• Cut irrigation costs
• Prevent seepage loss
• Deliver consistent water supply in dry seasons

Large agricultural reservoirs may use HDPE geomembranes lined from 1.0 mm to 2.0 mm thick depending on size of pond and soil conditions.

Mining Water Containment

Because many of the liquids held have chemicals within them and/or are contaminated in the mining fields, reliability must be built into the water containment geomembrane.

Some mining geomembrane applications include:

• Heap leach pads
• Tailings ponds
• Process solution ponds for recovery of minerals
• Evaporation ponds

In mining, chemical and acid resistance is of primary concern, so a geomembrane such as HDPE is used because it can resist acids and alkalis along with most harsh chemicals in industrial use.

Landfill Leachate Ponds

Most liner systems rely on geomembranes to minimize the risk of environmental contamination in landfill applications.

They much conform to stringent ASTM standards and quality testing procedures.

Other landfill applications that might incorporate a geomembrane include:

• Leachate ponds
• Secondary containment systems
• Capping systems
• Waste water storage lagoons

Biogas Digesters

Those digesters use organic waste and that organic material creates pressure in and outside of the geomembrane.

They must have a very durable impermeable membrane attached to handle both pressure and volume.

They also help:

• Retain biogas so loss of greenhouse gas emissions is minimized
• Reduce odor emissions
• Protect the environment
• Assure renewable energy recovery

These applications typically use flexible HDPE and more commonly LLDPE geomembranes.

Comparison or Benefits

Less Seepage

A geomembrane can be almost completely impermeable compared to compacted clay.

Better Water Retention and Less Leakage

Leaky ponds and lagoons are never a good thing.

The impermeability of geomembrane liners helps ensure greater water retention even in areas that may have previously leaked.

The result is improved water quality and better overall project outcomes.

Faster Installation

Manufacturers can produce large geomembrane panels covering extensive project areas.

This enables rapid installation and reduces field seam requirements.

Faster installation reduces:

• Construction time
• Labour requirements
• Equipment costs

Better Chemical Resistance

In mining and industrial applications, traditional liners may deteriorate quickly.

When you need a leak-free waterproof reservoir, an HDPE geomembrane is often the preferred solution because of its resistance to acids, alkalis, and industrial chemicals.

Longer Service Life

With a high-quality geomembrane properly installed, service life can be 20–50 years in most cases, impacted by:

• Soil dynamics
• Environmental exposure
• Installation quality

UV stabilizers and lots of carbon black content help long-term performance.

Lower Maintenance Costs

Properly installed geomembrane liners mitigate need for ongoing maintenance over concrete/clay systems.

How to Choose / Buy

Pick the Right Material

The use of geomembranes is growing so that municipal ponds, fish ponds, and reservoirs are all being done that way, along with industrial use.

But higher performance geomembranes are required for landfill, mining, and mineral recovery.

HDPE Geomembrane

Best For

• Landfills
• Mining
• Large reservoirs
• Wastewater lagoons

Advantages

• Strength and durability
• Excellent chemical resistance
• Long service life

LLDPE Geomembrane

Best For

• Flexible pond systems
• Irregular surfaces
• Where higher elongation projects required

Advantages

• More flexibility
• Lighter and easier project adaptation to irregular subgrades where needed

Select the Correct Thickness

Common thickness geomembrane are:

• 0.5 mm (20 mil)
• 0.75 mm (30 mil)
• 1.0 mm (40 mil)
• 1.5 mm (60 mil)
• 2.0 mm (80 mil)

For fish ponds and smaller, lighter-duty projects, a lighter liner can be used, but accurate thickness is essential for mining and heavy-duty containment so select regularly heavily published thicknesses.

Ensure They Are Manufactured Properly

Some information you might gain supplier reliability from would include:

• Carbon black content
• Actual tolerances on thickness
• ASTM test reports for thickness and other characteristics
• All published technical data sheets, including these items
• Check inspection policies

Don’t hesitate to ask for any guides other than the purchase guides beforehand.

Is Installation Supported?

Even the very best geomembranes can fail if seam welding, etc., of a system are shot.

Asking for installation assistance and obtaining good product information from the vendor is important for success.

Picks in seam welding, bad subgrade, bad anchoring, whatever, and zoom we lose the waterproofing expected of the system.

When you place an order, ask the vendor:

• About helping with welding etc.
• For video such as shown here
• Technical support numbers
• Welding tips such as seam repair
• See if a technician will come out to the job, too

FAQ

What is geomembrane?

Technically, they are impermeable polymeric membrane used to prevent unacceptable seepage of fluid through the soils in either water containment or environmental protection projects.

How does it work?

They provide a barrier that blocks water from “migrating” between the containment system and ground around it.

What is lifespan geomembrane?

Higher quality HDPE will achieve service life of 20–50 years in most cases depending on location, soils, and installations.

What is best geomembrane?

Generally, HDPE is the material of choice for mining, industrial, landfill and other large water containment projects.

Where more flexibility is required, people turn to LLDPE.

What are common geomembrane problems?

Most, fortunately, have to do with installation of the material rather than the actual product.

• Puncture during installation
• UV exposure
• Bad subgrade
• Bad anchoring
• Bad seam welding

Conclusion

Reliability is uppermost in the minds of most entering into a geomembrane liner project.

From mining ponds to easy agri-reservoirs geomembrane liners don’t seem to be letting us down.

Material selection, liner thickness, quality of installation, and environmental protection are what cause long term integrity.