Discover garden ponds and their environmental value

Owning a garden pond has many benefits including the great value it offers to wildlife and enhancing the environment in which we live. The intensively farmed country-side, use of agricultural sprays, draining of wetland habitats and expansion of towns and cities has resulted in the decline of many wild life species including the common frog – despite it’s name it is actually in rapid decline.

Benefits of building a garden pond

  • Provides a breeding habitat for many species Frog and frog spawn in garden pond
  • Offers a temporary home for amphibians and reptiles – frogs and newts find their way to water sources – newts favour ponds without fish.
  • Holds a diversity of species
  • Ecosystems are linked by water
  • They recirculate water unlike lawns and flowerbeds which require constant watering during warm, dry weather
  • The sludge collected by a ponds filter is rich in nutrients from fish faeces, uneaten fish food and decaying plant matter. It makes a natural fertilizer that can be dug into flower beds.

Ponds offer wildlife a home, breeding habitat and a source of food. However, it is not just the water feature, it is also about the landscape surrounding a garden pond that is of great value.  For example, newts leave hibernation between February and March, returning to ponds for breeding with pond plants providing egg-laying locations. They also need an undisturbed habitat around the pond, providing refuge and good feeding sites. By not paving all of the green space in your garden and being less of a perfectionist when it comes to tidying flower beds, are valued by wildlife. Piles of dried leaves are home to frogs, newts and many other small creatures. Gardens and ponds work in harmony to help the environment – plants, shrubs and trees haver air purifying properties reducing the toxic effect of air pollution.

A garden pond offers important benefits to us too. Ponds offer a sanctuary – a place to go to relax and shut yourself off from the rest of the world – listening to the tranquil sound of water while watching nature at it’s happiest!

P.S. Butyl and Epalyn pond liners are environmentally friendly products and don’t leach toxic chemicals into the water.

Why quality matters when buying a pond liner

Pond liners serve two main functions in pond construction. A pond liner is impermeable and maintains water retention – stops ground seepage.  They also serve to keep sediment and other debris out of your pond. Today shops and online stores are filled with a choice for every conceivable item and pond liners are no exception. But, knowing what qualities in an item to look for to give the best return on investment can make the experience less daunting. Continue reading

Tips on essential Spring garden pond maintenance

The daffodils are awakening and filling our gardens and countryside with splashes of yellow. A most welcoming sign that Spring is soon to be with us – the days are getting longer and there is more time get things done outdoors. Daffodils in flower welcoming the coming of Spring

All garden ponds require regular maintenance to keep them looking good. Deep ponds do tend to remain cleaner than shallow ones. Algae, particularly blanket weed tends to occur in newer ponds where a balanced ecosystem has not yet been established or in one which is overstocked with fish. The best way to deal with algae is to remove it on a regular basis using a plastic rake to remove the filamentous weed. Barley straw is an environmentally friendly treatment for blanket weed. Submerge mesh bags of barley straw just below the water’s surface in early spring (replace the straw when it turns black). Chemicals released when the straw decomposes inhibits the growth of algae.

Garden pond spring checklist

While we still have a few weeks to go before it is officially Spring, it’s important to schedule in a pond care checklist for when the days do start to get warmer. Spring will also become evident when fish start swimming around more energetically and plants are poking green shoots above the water. Koi fish should not be fed until the pond water temperature is stable at around 55 degrees F (12 degrees C).

Things to do in spring:

  • Give your pond filter a good cleaning. If you have a bio-filter, give it a boost of a bacteria/enzyme product to ensure a good bacteria colony starts to grow in the bio-filter.
  • Clean your pond pump and check all hoses for leaks or cracks.
  • If you have a net covering your pond, make sure it is still intact, if not, replace it.
  • Remove leaves or other debris in your pond – as the water warms up, any debris left in your pond will start to decompose and affect the health of fish.
  • Check your fish for any illnesses or wounds.
  • Divide and repot pond plants. Avoid re-potting with soil full of organic matter. Most water plants grow well in sand and don’t require fertilizer. Water lilies are, however, an exception and do require fertilizer for a healthy growth. Water plants get their nutrients from fish waste. If you have extra plants after you have divided them, you may want to consider growing them in low, damp spaces in your garden.
  • For fish ponds, make sure that up to half of the surface of your pond is covered with floating plants as it gives the fish a place to hide from predators and keeps them cool in the heat of the summer. It also keeps the sun from encouraging algae growth.
  • If your pond is lined with a pond liner check that the material you have used for the edging is still in place, sufficiently covering the pond line to prevent any possible damage from claws or the UV rays – rubber pond liners are UV stable and will withstand long periods of UV exposure – but, a bare edging exposing a pond liner can detract from the beauty of the pond.

Spring marks a time when ponds come back to life after the winter lull. Frogs will start visiting garden ponds to spawn. Gold fish start to awaken and the males start to feel frisky chasing the females around the pond. Insects start to hatch. Herons will be getting ready to nest and on the look out for an easy meal of goldfish or koi – look out for them in the early hours of the morning. Spring is also a time for growth, so look out for your aquatic plants and make sure they don’t start occupying all of your pond.

HAPPY SPRING CLEANING – when the good weather arrives!!

Tailored pond liner project photographs

Liners Online supplied the pond liner for this complex pond design. The pond is sited in a residential garden in Scotland with stunning effect against the majestic mountainous backdrop. The complex pond design required a tailored pond liner and protective underlay to fit to the exact dimensions minimising creases and folds as much as possible.

We are passionate about the pond liners we supply and have years of experience in the business including on site installation and fabrication. Please visit our website for details on our pond liners and our Epalyn pond liner kits.

How to go from inspiration to design to building your pond

Pond building success is derived from passion and inspiration. If you are thinking of building a water garden, do your research first by looking through landscape and garden related magazines or visiting public gardens – inspiration is usually drawn from something that has grabbed our attention resulting in a nagging urge to create a similar effect in our own garden. Being inspired is all the motivation you need to get started!  From inspiration you then need to be able to visualise what it will look like in your own garden. I always suggest standing at a window on the second or third floor of your house and spend time looking out over your garden picturing exactly where you plan to site your pond, the shape and how it will blend in with the surrounding landscape.

Inspired? Now start planning your pond

  • first decide what type of pond you want – either formal, natural or bog garden.
  • closely observe the site you wish to build your pond and take note whether the site gets enough sunlight, whether your garden is the right size and shape for what you have in mind and what you can afford.

A formal pond can be created from a box-welded pond liner in conjunction with brick, wood, concrete and stone. It can be raised or built into the ground.

Natural pond created using flat sheet pond liner secured in place using paving or crick edging material.  No matter which pond liner you decide to install, the secrete to a successful pond build is to make sure that the edges are concealed either under ground or by using edging materials such as brick or paving stone. To guarantee the life of your pond liner it must be installed above a protective underlay. If your inspiration is derived from a passion to stock fish and aquatic plants – go for a natural type pond. Build a pond as big as your garden will allow with shelves built into the sides and a sloping edge. Pond must be positioned so it gets more sun than shade.

Once you are quite clear what you want you can start putting pen to paper and do a scaled plan listing all the materials and equipment needed too. Make sure there are no underground cables or pipes on the site you intend building on.

As part of the visualisation process, take your scaled drawing and map it out in your garden using spray paint, sand or rope. Go back upstairs and look out over your garden again. Does your design work? Make any adjustments until your design matches what you had visualised. Also ask yourself if your design idea is practical for your garden size, does it work in harmony with the rest of your garden – is your plan realistic? Established garden pond to inspire your own plans.

Your plan also needs to include ways in which the water in your pond will be filtered and oxygenated. If you don’t want to keep any aquatic plants or just a few but want crystal clear water in your pond, you will need to install a filtration system to break down waste products and debris. Ponds need oxygen as part of maintaining a healthy ecosystem. It is important for aquatic life to thrive keeping a pond from going green and fish from dying. Oxygenating plants absorb carbon dioxide and give off oxygen therefore a great idea to stock these in a pond. An alternative is to install a fountain because moving water increases oxygen levels and therefore is healthier than stagnant water.

Choosing aquatic pond plants

  • aquatic plants are chosen not only for their inherent qualities but also for their effect adding height, breadth and colour to the overall scene. They oxygenate the water, provide food and offer protection to pond creatures.
  • read labels and try to imagine the effect it will have to your pond once it has grown to maturity.
  • consider style of pond matched to visual impact of plant.

Inclusion of fish

When introducing fish you need to consider the mature size of the fish and the habitat you will be introducing them to. A water garden that is too small or fish that are too big will lead to problems.

The depth, average water temperature, size, moving versus still water, amount of daily sunshine versus shade – are all important factors to take into account when deciding on number and type of fish. Introduce just a few native fish to start with and see how they cope.

If you have dreams about building your own water garden, this article provides a guide on the stages necessary to get you started. Now is a great time to make a start on your project – the ground is damp and there is just enough time to get the job done by the start of Spring.

Box-welded pond liners customised to customer requirements

Box-welded pond liners are better suited to some pond builds especially regular shaped ones where a 2-dimensional pond liner installation will result in unsightly folds and creases. A box-welded pond liner is cut and fabricated or hot bond welded to the dimensions and design submitted by the customer. An overlay lip is included upon which flagstone or other edging material can be placed to secure the box-welded liner in place. The pond liner is then slipped into the pond dug-out – and above a sheet of Geotextile protective underlay liner. The result is a perfect fit to a formal pond.

Vertically sided ponds create a splendid feature in any garden and are often home to Koi-fish. Liners Online have the expertise to cater for ponds from simple designs to more complicated ones – including those with planting shelves, sloping bases, uneven depths or a haunched base to fit a bottom drain. For very sophisticated designs, the box-welded pond liner can be welded onsite.

Box-welded pond liners are also referred to as custom-made, tailored-to-fit, bespoke or made-to-measure liners. Butyl and Epalyn (EPDM) pond liners are a synthetic rubber material from which a box-welded liner is made. To assist in providing a box welded pond liner, a drawing is needed showing all the dimensions.

Box-welded pond liners fabricated from rubber pond liners

  • gives a relaxed fit with no stretching
  • UV resistant
  • made-to-measure from simple shapes to intricate designs can all be catered for
  • gives a neat and professional finish (eliminates creases and folds which have the potential for harbouring debris)
  • tear resistant
  • certified non-toxic to fish or other aquatic life
  • comes with a 25 year guarantee provided it is installed above a protective underlay

Box-welded pond liners made for customers

Here are just some of the formal pond designs for which we have fabricated and supplied the pond liner:

Box-welded pond liner fabricated for this customers pond Rectangular pond with vertical sides fitted with a box-welded pond linerFitting a box-welded pond linerFormal garden pond with box-welded pond liner installed to give a neat crease-free finish

Raised pond lined with box-welded pond liners

Box-welded pond liners not limited by pond design

Pond liner installed to a complex pond design

Sharing this review kindly sent to us by one of our customers is testimony that we don’t just sell a pond liner or product, but also our knowledge and expertise to help and advise. We will work with you on your pond design to tailor a pond liner to fit to exact dimensions. Whether you want a flat sheet pond liner or one that is welded to a formal ornamental pond design to fit ‘like-a-glove’ without any folds or creases.

A review sent to us by a customer to whom we supplied the Geotextile underlay and 1.00mm Epalyn pond liner for his unusually shaped garden pond – “I explained my proposal for an odd-shaped liner, and the team at Liners Online came back with several options, which we refined to to a cost-effective, but still complicated shape. The order was delivered only 3 days later, as promised, and is obviously an excellent product with which I am totally satisfied. I would recommend this company to any pond-builder.”Chris Yarrow of East Sussex.

For this pond liner order we took a sheet of Epalyn rubber and cut it to the required lengths before vulcanising them together to form the finished pond liner. The flexibility of a pond liner allows the freedom to design a pond that suits individual requirements without any restrictions imposed. Just dig your pond the shape you require and contact us and we will advise you on the best size and material for your pond. All rubber pond liners come with a long-term warranty for added peace of mind.

Here are photographs Chris shared showing the underlay installed and secured in place using old bricks while they got to work to lay down the pond liner.  The second photograph shows it filling with water. We have been promised a few photos of the end result once completed in a few weeks time once the edging has been laid to secure the liners in place. Work in progress and we can’t wait to see the end result!

Laying the pond liner and the early stage of filing the pondLaying the pond liner and the early stage of filing the pond

This entry was posted on February 1, 2017, in Garden ponds.

Why a compost bin is a good investment for gardens

Compost bins are a neat and easy way to turn waste into a nutrient rich fertilizer. Composting is a valuable process by which life is given back to the soil. Compost is decomposed material made from waste that other wise would have gone to landfill. Green leaves, fruit and vegetable scraps, egg shells, fresh grass clippings, tea bags, used coffee granules, cardboard egg boxes and twigs can all be thrown into a compost bin.

Advantages of investing in a compost bin

  • saves money on buying chemical-based fertilizers
  • compost will enhance the quality and texture of soil by improving its ability to hold moisture and nutrients
  • compost produced and fed into the ground will improve the texture of clay and sandy soil by making them more loamy and increasing the ability to hold water for longer
  • compost improves soil aeration and drainage
  • dig compost into flower beds to control weeds
  • reduces landfill – garden and kitchen waste sent to landfill and start to decompose in the absence of oxygen. The result is methane gas released into the environment – a by-product that contributes to global warming

The composting process can be speeded up by regularly aerating it. This is done by turning and mixing the content of the compost bin once a week. When it looks, feels and smells like rich dark soil then you know it is ready to dig into the ground.

A tumbling compost bin will make home composting easier – you won’t need to get out your gardening fork to mix and turn the compost. With all the benefits as listed above, why not invest in a product that will help simplify the home composting process?

Benefits of a tumbling compost bin 

When mTumbling compost binaking your own compost, it is important to remember that aeration is vital for the organic matter to break down properly. So, when comparing a standing compost bin to a tumbling compost bin, there are a few factors you need to consider. Firstly, a tumbling compost bin does exactly what its names states – it tumbles – and the rotating function is what ensures that the organic waste gets the aeration it needs to decompose and produce high quality compost. If you use a standing bin, you would need to aerate the compost yourself with a shovel or garden pick. This process is not as effective and it means more effort for you and may ultimately cause damage to the bin itself as well. The second point to consider is the strength and durability of the bin. A tumbling compost bin is made of stronger heavy-duty materials as it is designed to support the full load of the compost.

Finally, we need to consider convenience. Working with compost can be a messy and smelly job. A tumbling compost bin empties from the top and is mobile, meaning you simply have to wheel it over to where the compost is needed and tip it over to access the contents. Standing bins, which empty from the bottom, are immobile and therefore require a lot more hands-on participation.

By recycling your organic waste as compost at home, you are making a significant impact on the environment – and you will enjoy the benefits in your own garden by nourishing your plants with all the essential nutrients and minerals they need. At Liners Online, we are committed to environmentally friendly practises and sell a range of garden related products – from pond liners to solar lighting and tumbling compost bins . So contact us today and get composting!

Garden ponds and the value of submerged aquatic plants

A survey conducted in 2015 found that an average of one in ten homes across Britain have a garden pond or water feature. This statistic is encouraging although still doesn’t quite match the lose to wildlife of natural ponds and lakes. No matter what the goal is for a pond owner, whether for fish or to encourage wildlife, they all provide a habitat for amphibians, water insects, birds and small creatures. Ponds require less maintenance than that of a garden provided there is a good balance of aquatic plants, often referred to as natures best filtration system.

Under water photo of submerged aquatic plants

Garden ponds are defined as shallow bodies of water of up to 2 meters deep. The sun is able to penetrate such depths casting it’s rays to the bottom of the pond creating the perfect environment for submerged plants to grow. Floating plants such as the commonly know water lilly, grow on the surface and have no root system. They are beneficial in providing shade and shelter to pond inhabitants, but if not managed can grow across the surface blanking out the sun and preventing photosynthesis. Covering no more than 60% of the surface will prevent algae growth while providing sufficient shelter to pond creatures.

There are four types of aquatic plants, namely floaters, submerged, marginals and oxygenators. All offer benefits to maintaining a healthy pond ecosystem so it is good to add a few of each type – how many is dependent on pond size, depth and goal of pond. A healthy pond ecology is about balancing the life in your pond with the environment within – a shallow pond with little movement of water fully exposed to the sun and rich in nutrients is the perfect environment for algae growth. Not quite what a pond owner wants to see happen!  This is important to note when setting your goals for a garden pond.

Aquatic plants offer numerous benefits to garden ponds. They are important to the life of fish and wildlife because they provide cover from danger, nesting areas and food. The presence of aquatic plants really depends on the goal for a pond with wildlife ponds likely to have a greater variety of plants versus a pond housing fish. Submerged plants are important to both types of ponds. They provide protection to small fish, release oxygen into the water and absorb and provide long-term storage of nutrients (that might otherwise be used to increase the levels of algae in a pond). Ponds with submerged plants have fewer problems with algae. However, grown in abundance and they could cause problems for fish pond owners.

The advantages to aquatic plants in garden ponds

  • a decrease in water clarity can often be solved by adding submerged or oxygenating plants
  • known as  natures natural filtration system
  • provide food and shelter to aquatic life
  • aesthetically pleasing to a pond giving it character and dimension

Before rushing out to buy aquatic plants for your pond, here are three important things to note: some plants thrive in moving water while others prefer still waters, buy from a reputable aquatic trader who is more likely to sell disease free plants and buy native plants.

Can you feel the days getting longer – soon we will be outdoors soaking-up the sun while enjoying the tranquil beauty of our garden ponds!



This entry was posted on January 18, 2017, in Garden ponds.

Why choose an EPDM pond liner for your pond?

EPDM pond liner (ethylene propylene diene Monomer) is the ideal solution for water retention and widely used to line lakes, garden ponds and man-made streams. EPDM is a synthetic rubber with properties very similar to butyl pond liner and has become a leading product for lining garden ponds. EPDM pond liner has many superior technical features such as resistance against root penetration, unaffected by UV radiation, durability, withstands adverse temperature range of -40 to +150 C and has a proven long service history. This pond liner is seen as the cheaper yet slightly more superior alternative to Butyl pond liner.

When you type “EPDM” into the search engines you will be taken to a choice of roofing specialist websites. This is because the synthetic rubber membrane is a very popular choice in the roofing industry but it is not to be confused with EPDM pond liners, also known as Epalyn pond liner. The rubber membrane used to line ponds, lakes, streams, water storage tanks and reservoirs is fish-friendly and is also used to line potable water tanks. For this reason EPDM pond liner should only by ordered from companies in the aquatic trade such as Liners Online.

EPDM pond liner is available in three thicknesses of 0.75mm, 0.85mm and 1.00mm. This makes EPDM pond liner suitable for a range of application types from the humble garden pond through to the most demanding large pond or lake builds.

For natural ponds, EPDM pond liner can be supplied as a single sheet to your required size, and then trimmed to the exacting shape once installed.

For formal shaped ponds (with vertical sides and a flat base), including Koi and ornamental ponds, EPDM can be fabricated and supplied as a box-welded pond liner. The advantage of this design is that they can be installed into a pond dug-out without any unsightly folds or creases. This 3-D effect pond liner is fabricated in our factory and supplied as a single item. Box-welded pond liner fabricated from EPDM pond liner

EPDM pond liner performance

An EPDM pond liner is guaranteed life-time for orders under a 100 m squared or for 25 years for orders over 100m square. If installed above a Geotextile protective underlay it is likely to provide a lifetime of water retention. However, should your pond be visited by a sharp clawed creature, you can be assured that rubber pond liners are readily repairable using Mastic tape or a pond liner repair kit.

We are passionate about the pond liners we supply and have years of experience in the business including on site installation and fabrication. Please visit our website for details on our pond liners and our Epalyn pond liner kits.

How to drain run-off away from your garden pond

How we go about planning and building our garden pond goes a long way toward it’s ultimate success. The quality of water is a good measure of how well a pond has been built and maintained. This is evident in the health of fish and other living creatures inhabiting it. Where you site your pond and how well you maintain the surrounding landscape also contribute to the health of a pond. Ultimately you would want a low maintenance pond which sparkles with health and vitality.

Rainfall on impervious bricks causing runoffSo, what is the relevance of all this? To put it simply, as our towns and cities expand so does the amount of impervious ground cover over which rain has to pass before going down a storm water drain or finding ground it can seep into. Our gardens are no different with patios and driveways having a negative impact during periods of high rainfall. Rainwater run-off is precipitation that doesn’t soak into the ground. This can be due to the ground being saturated, having a non-porous soil type or man-made surfaces preventing water being absorbed into the ground. Rainwater run-off can become a problem when it carries with it leaves and other debris. If this water should then flow into your pond it will affect the health of your pond by reducing the waters oxygen levels.

We plant and fertilize our flower beds, shrubs and lawns. But, in the process we change the environment by adding nutrients and organic matter to the soil. These can all have an unintended negative impact on the water in our garden ponds, lakes and streams. Polluting our waterways affects the health of all living creatures that inhabit it. Sudden down pours of rain can cause flash flooding which can carry silt, grass clippings and other debris that lead to murky water. Lawn fertilizers contain chemicals that can support algae growth or harm aquatic plants and fish. There are, however changes that we can make to reduce run-off in our own gardens.

Careful selection of where you site your pond is an important step to avoid pond water health problems. The ground around a pond should hold sufficient clay content to retain water. Rainfall and runoff from impervious surfaces

How to reduce rainwater run-off into your pond

  • minimize man-made impervious surfaces
  • plants absorb water so  grow sufficient to cover your flower-beds
  • native plants have extensive root systems so include these in your garden to absorb rainwater before it becomes ‘run-off’
  • dig organic matter into your flower beds – plants will also grow faster and have a greater impact in reducing run-off
  • reduce slope of garden to restrict the risk of run-off

Man-made rainwater run-off prevention

If the above mentioned steps are not sufficient in preventing runoff, you can protect your pond by digging a slight ridge around it. The ridge doesn’t have to be very high. If the pond is on an incline, you can create a shallow channel with a slight slope to divert runoff to a flowerbed.

The impact of Global weather changes on Great Britain has seen periods of dry spells followed by heavy and persistent downpours – it is these that can affect the health of our ponds so we hope the tips offered in this article prove helpful.

For more steps to building a healthy garden pond, visit this article on our website >> Pond planning and Construction

This entry was posted on December 12, 2016, in Garden ponds.

How long do pond liners last?

Pond liners last many years if installed correctly. Most manufactures of rubber pond liners offer at least a 25 year guarantee provided the pond liner is installed above a protective underlay. For Butyl or Epalyn pond liners up to 100m2 in diameter the guarantee offered by Liners Online is life-time. Pond liners bigger than 100m2 are guaranteed for 25 years. Butyl pond liner, a 0.75mm thick synthetic rubber has been used to line ponds in the UK for over 40 years with great success and is still considered to be one of the best pond liners on the market. 

Pond liners are essentially a waterproof fabric whose function it is to keep the water from seeping into the ground. Not all pond liners are made equal therefore it is advisable to check the guarantee terms and conditions before placing an order. The guarantee period is just a gauge on how long you can expect a pond liner to last. Pond liners being installed above a Geotextile protect underlay

Types of pond liners

Pond liners vary in strength, flexibility and durability depending on what material they are made from:

  • PVC pond liners – usually around 0,5mm thick. The liner is flexible, however it is not tear resistant so if the material is punctured, it may get worse over time. PVC pond liner will go brittle and crack if exposed to the sun over a period of time therefore correct installation and maintenance are essential. PVC can’t be easily repaired as most pond liner repair products cause the liner to go brittle around the area it is applied to leading to further cracks and leakages. Protecting it with an underlay liner is essential to help prevent leaks. PVC pond liners last around 20 years. 
  • Rubber pond liners – These liners can be further divided into EPDM (Epalyn) and Butyl, the latter of which has for long been considered one of the best materials by pond enthusiasts. EPDM, on the other hand, is less costly and has similar, if not slightly better characteristics than Butyl. Both pond liners are known to last upwards of 30 years. Should either puncture they can readily be repaired without a costly replacement.
  • Preformed pond liners – they are of a predetermined size and shape that can’t be changed. Made of fibreglass or a rigid plastic with pros and cons to both types. Fibreglass is expensive but can be installed above or below ground level. Rigid plastic liners must be installed inside the ground to prevent them from flexing and cracking. A preformed pond will last upwards of 10 years. Ground movement can cause cracking with age so generally have a shorter life span than a flexible rubber pond liner.

Can a pond liner be installed directly on the ground?

Yes, you can however we don’t recommend doing so as this affects the guarantee on the liner. There is also a much higher probability the rough surface of the ground will puncture the pond liner. Liners Online supply a non-woven, mechanically bonded, needle-punched, Geotextile underlay. It offers high performance and provides a highly effective protective barrier between substrate and pond liner. We recommend that an underlay is used beneath all our pond liners, not only to help protect the pond liner from penetration by sharp stones and roots but also to reduce excessive localised stretching of the liner when ground settlement occurs over time.

In summary, a flexible PVC or rubber pond liner will last 20 years and more provided they are installed above a protective underlay, secured in place with appropriate edging material and protected from regular clawed animal visits. A well maintained and cared-for pond should give you years of pleasure.