Can you have a pond without a liner? The short answer is yes!
However, bear in mind that a good pond foundation often relies on the pond liner. Although it’s possible to not have any, you have to consider the clay content level of the compact soil and the depth of the pond.
Whether you’re planning to build a pond without a liner or just want to fulfill your curiosity, you’ve come to the right place. In this article, we’ll explore everything you need to know about a no-liner pond.
Pond liners are a favorable choice because they prevent leaking. In addition, they keep the water levels from dropping.
Aside from that, they also control the sediment level at the bottom of the pond.
However, if you choose to have no liners at all, here are the things you should consider before building a no-liner pond:
The soil composition will determine if your pond can do without a liner or not. For instance, compacted soil needs to contain at least 20% clay content to prevent water seepage into the earthen structure underneath.
Having impermeable soil is important, especially for a pond that uses surface runoff as its water source. Other than that, the foundation of the pond and the spillway design will determine the pond’s capability to retain water.
To check if you have sufficient clay content in the compacted soil, you can use soil testing kits from the Natural Resource Conservation Service.
Once you’ve ensured that the soil results are acceptable, the next thing you should consider is the depth of the pond. Try to keep the pond at two to three feet deep.
Yet, keep in mind that you’ll probably need to add more if you want to grow aquatic plants.
For instance, allow another 30 inches of depth for the planting soil and 12 inches for the clay-loam soil. These layers will prevent the roots of the aquatic plants from disrupting the impermeability of the compacted soil.
Moreover, make sure that the depth doesn’t exceed 10 feet of static head pressure because it can risk water seepage through the pond walls and floor.
A traditional pond requires a circulating pump and a mechanical filter. These filtering systems can cost up to a hundred dollars. However, they’re a good investment because they keep the water clean and provide a healthy environment for aquatic animals.
On the other hand, a no-liner pond can make a clean and hospitable home for aquatic pets by taking advantage of microorganisms. Some examples include arthropods, bacteria, and protozoa.
Typically, living creatures, like frogs, fish, and insects can add organic matter to the pond. When these organic materials accumulate, they can lower the water’s oxygen levels.
Luckily, microorganisms feed on organic matter and maintain a balanced ecosystem.
Generally, nutrients in the pond help living things grow and thrive. However, algae can quickly take over the whole pond if the nutrient levels become too high. Even worse, it can choke out other aquatic animals, like fish.
Fortunately, you can reduce algae growth by planting aquatic plants and flowers, such as water lilies, lotuses, and Water Poppies.
Not only will they make beautiful additions to the pond, but they can also out-compete any algae growth.
You can also grow marginal plants. Aside from controlling the nutrient levels of the pond, setting them along the small stones on the ledge can help reduce the pond’s exposure to sunlight.
Keep in mind that sunlight makes algae grow faster. Hence, it’s wise to shade your pond as much as possible.
Although most homeowners prefer ponds with full liners, there are several options for constructing a pond without a cement shell. Here are three ways you can build a pond with no liner:
The gleying technique uses organic material to create a decaying layer that will serve as an anaerobic seal. Gleying imitates the Russian-devised method where they use animal waste and organic matter, like grass and leaves.
However, it’s recommended to skip plant material and use animal waste instead, such as duck and pig manure.
As the name implies, this method uses clay. Typically, the method requires finding clay on-site and shaping or compacting the material to seal the pond.
However, if you live in an area made of shale, this may not be an ideal option.
Unlike clay, shale is too brittle to create a compacted layer. Aside from that, purchasing clay off-site will be more expensive and will require intensive labor.
Hence, if you don’t have clay on-site, gleying is a better alternative.
Another way you can build a pond without a liner is by finding a naturally wet area on your land.
Basically, all you need to do is dig and deepen an already existing wet area. To make a low bank, you can remove plants right where you want the body of the pond to start.
The depression in the ground keeps the water from rising. As a result, the pond no longer poses a danger to your household pets and neighbors.
Using soil additives, like bentonite, is another alternative to constructing a pond with no liners. Bentonite is a colloidal material that can expand up to 10 times its size when it gets wet to effectively seal soil pores.
To create an impermeable layer, you can spread 10 to 30 pounds of bentonite per square yard of the pond’s surface area.
If you’re building a pond in your backyard, it can be tempting to use common materials like tarpaulin. Although it’s possible to use a tarp as a pond liner, you have to make sure that it’s high quality.
A great example is vinyl tarpaulin. It’s 100% waterproof, so it can prevent water from seeping out into the soil.
It’s also tear-resistant and UV protected. Plus, it’s safe for your aquatic plants and fish.
A pool liner is an expensive option. Typically, it’s made with water-resistant materials that can prevent the growth of mold and algae.
However, if you want to use a pool liner as a pond liner, you should also consider its thickness.
For instance, if you live in an area that has winter months, it’s best if you get a pool liner with thick lines. This way, it’ll be more resistant to puncturing or tearing.
On the other hand, a thick pool liner won’t be necessary if you live in an area that stays warm all year round.
So, can you have a pond without a liner? Yes, you can.
However, you need to consider the soil composition and the depth of the pond. You should also consider growing plenty of aquatic plants and letting microorganisms thrive to help maintain a balanced ecosystem.
Moreover, you can construct a pond with no liner by using the gleying method or clay method. Another good idea is to excavate an existing wet area or use soil additives.
Ben has a bachelor’s degree in construction engineering. When not constructing or remodeling X-Ray Rooms, Cardiovascular Labs, and Pharmacies, you can find him at home with wife and two daughters. Outside of family, He loves grilling and barbequing on his Big Green Egg and Blackstone Griddle, as well as working on projects around the house.
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