As you can see in the pictures above we had essentially a hole in the ground that we dug for dirt to build our pad prior to sealing our pond. My research yielded the following solutions to sealing ponds.
Sealing Ponds with a PVC LinerA PVC liner is essentially a sheet of flexible plastic that you line the bottom and sides of you pond with. PVC liners are manufactured according to various thicknesses, and the thicker it is, the longer it lasts, and the more expensive it is.
There are obvious positive and negative aspects to a PVC liner:
Positive – It seals the pond tightly with no water loss.
Negative – It is subject to UV sunlight damage over time. If you have trees the roots can penetrate the liner over time. Sharp rocks will also puncture it. The solution for this is a pre-lining pad that you put under the liner.
Sealing Ponds with a Preformed Pond Liner
Preformed Pond Liners are available at almost any home center. They are made of thick, rigid plastic.
Positive – Seals tightly and last a long time.
Negative – Small size and they limit you to their preformed shape.
Sealing Ponds with a EPDM Liner
A EPDM liner is similar to a PVC liner, but it is made of a higher grade material that is more resistant to UV damage. EPDM is used in many applications that require UV resistance, flexibility and long life. One of these applications is roofing materials. Needless to say, it is very expensive.
Positive – A good seal and good UV protection.
Negative – Expensive and difficult to deal with.
Sealing Ponds with Natural Clay
A Natural Clay Liner is made of natural clay from the ground. Natural Clay can be bought by the truckload from a local dirt yard or sand pit in your area. They truck the clay to your pond and then work it into the walls and bottom of the pond using heavy equipment.
Positive – Materials are usually readily available. You should be able to find a contractor in your area to install the clay.
Negative – No guarantee it will seal. Heavy equipment is required to install the clay. If your contractor does not get a uniform clay thickness, you will have leaks. Can be very expensive with no guarantee of performance.
Sealing a Pond with Sodium Bentonite
Sodium Bentonite is natural clay that is mined principally in Wyoming and Texas. It is used as a sealant and lubricant for drilling oil and water wells. It is also used to seal retention ponds, garbage dumps and any application that a good water tight seal is important.
Positive – Relatively inexpensive and can be installed with simple equipment.
Negative – Large quantities are needed to properly seal a pond. Very labor intensive installation. You must maintain an adequate thickness to get a good tight seal.
Why I used Sodium Bentonite to seal my pond
We used Sodium Bentonite because we could do much of the labor ourselves and we could buy quality materials ensuring a good seal. No one in my area would guarantee my pond would hold water using natural clay. They all wanted 30 to 40% more than I could do it myself using Sodium, Bentonite. I figured if I was going to spend the money I wanted to control the process and make sure I only had to seal the pond only once. I got a bid from a company that would guarantee a bentonite seal, but the cost was going to be three times higher than what I spent. Thankfully, I made the right decision and did it myself.
For a pictorial overview of the process go to the Sealing Ponds Picture page.
For information on Pond Fountains go to the
For pictures of our ponds go to the
For more Information on Building Your Own Home Go to Our Building Knowledge Center.
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