Buying pond liner for a sustainable water feature can be like buying a used car.
There are all kinds of different liners, for a variety of different uses. Which can all be very confusing.
Lets start by defining what pond liner actually is.
Wikipedia's definition.. : A pond liner is an impermeable geomembrane used for water retention, including the lining of lakes, garden ponds and artificial streams in parks and gardens.
So simply stated the goal is to hold water in the liner and not let it pass into the ground. Simple enough. But, here is where it gets tricky.
What pond lining material you choose depends on a variety of factors:
- How long do you intend to have the water feature
- Are there animals or dogs in the area that can easily puncture the liner
- How hard is the pond liner to install
- What kind of budget do you have
- What is the intended look of the finished product
- Will the pond lining need to be fish, animal, and wildlife safe
- How will maintenance be done
- Will there be any material on top or below the liner
- Will settling or erosion be an issue
- What type of weather will the liner need to withstand (freezing and thawing or extreme heat)
- Will vegetation with sharp roots be growing in the pond
- What will the water in the feature be used for - Aquaponics may require a very strict liner to not leach anything into fruits and vegetables
- Will you be using one continuous piece of liner, or multiple
- What will be needed as a substrate - Gravel, clay, geotextile, venting, etc..
I recently highlighted many of the liners available today on a Biologic Performance, pond liner page. But for simplicity I will touch on a few basic choices. What I would personally use on projects.
- EPDM Pond liner - Mostly available in 45 mil thickness and is fish, plant, and animal safe. Currently a majority of water features are built with this material due to its ease of use and cost. If you have a basic water feature in a normal size stick with EPDM.
- Concrete and Polyurea - While you will have to have these professionally installed. They are worth the cost if you want your feature to last a lifetime with minimal hassle. You will also need to go this route if you're planning any aquaponics or hydroponics. As Polyurea is non-toxic, stronger, and safer to use than EPDM.
- Clay - If you have a really large pond or lake look into mixing some clay into the soil. As the cost and hassle of lining it with something like EPDM will not be worth it.
Those are really my three go-to choices for pond liner. While there are numerous other choices, I feel like no matter the project these three liners can get the job done easily and effectively.