When an aquaculture pond doesn’t have a proper liner, the fish are often exposed to a wide range of diseases directly from the soil itself. Plants, animals, and fish in nearby water sources tapped to fill the ponds or raceways contribute even more disease risks. Hydrocarbons also rise through the soil if there’s any drilling or mining activity in the area. With all these risks, why wouldn’t you use a solid barrier to prevent contamination? Geomembranes are the best way to seal off the water and keep it clean and stable. By choosing an impermeable liner, it’s possible to prevent these problems and ensure a stable harvest that brings in the expected amount of harvest. Even if you only want to start an aquaculture project for a community food resource, you’ll need geomembranes instead of these other common liners to optimize the value of the system.
Concrete
Concrete is strong and semi-permanent, but it’s also expensive and requires skilled labor to pour and shape. Setting up the forms wrong results in an expensive pond or tank that leaks from the beginning. Even when built correctly, concrete liners naturally seep at some rate because of the porous nature of the material. Capillary action slowly draws moisture through the concrete unless there’s a barrier on one side, such as a layer of geomembrane. When concrete is required for its structural benefits, pair with a geomembrane liner for impermeability.
Rigid Pond Liners
Rigid liners are attractive to newcomers to aquaculture, but they’re all wrong for any kind of productive fish raising. First, they’re highly limited in size and rarely come in sizes large enough for raising more than a handful of fish. They’re also difficult to clean and can’t be easily cut to allow for pipes and drains to penetrate. They’re more expensive per gallon than spaces lined with flexible geomembranes, and they’re prone to cracking when soil settles or frost damages the system.
Above-Ground Tanks
The most widely used type of containment method in aquaculture after the in-ground raceway is the above-ground tank. These tanks tend to be cast from fiberglass, extruded from plastic, or formed from sheet metal. They’re heavier, expensive to ship, and come with a limited lifespan depending on the material. While they’re unavoidable for some tasks like settling and treatment tanks, they have many better replacements like in-ground ponds and raceways lined with a flexible material.
Natural Clay
Some aquaculture systems in the past, relied on ponds lined only with natural clay like bentonite. Before you assume this clay will cost less than a reliable RPE liner, consider the fact that you have to add anywhere from 12 to 18 inches of the material to properly seal a pond. This material also need replacement every few years, or at least the addition of multiple inches of fresh clay. All that cost adds up, especially for a highly permeable liner that doesn’t do much to stop water loss through seepage.
It should be clear now that most other liner options can’t compare to today’s multi-layer RPE liners. Aquaculture opportunities are expanding precisely because it’s easy to send these materials where large pre-cast tanks and concrete pouring trucks can’t go. If you’re ready to get started on your own aquaculture innovations, contact us today at BTL Liners.
