There are multiple options for ditch lining, yet only a handful of them are worth the cost and effort. Many ditch owners and municipal managers make the mistake of assuming that all pond lining methods work equally well for ditches and canals. Yet, the narrow design and steeply sloped walls of the ditches cause them to function differently; changing liner requirements significantly. Unless you want to spend extra time and money on maintenance, stick with flexible liners since they’re the best materials for ditch lining.
Least Effective: Unlined or Natural Clay Liner
Leaving the ditch unlined or hoping that a naturally high content in the soil will form a seal is the least effective option. Clay lining products designed for ponds also fail to work in ditches since they must be applied 12 to 24 inches thick in most cases. Some ditches are only this deep to begin with, leaving no extra depth for layers of bentonite powders. All of these options risk a lot of seepage and won’t hold up to the flow generated in even the smallest of ditches.
Acceptable: Spray Liners and Rock Layers
The first option for lining ditches is to apply some kind of polymer-based spray liner or a layer of rock known as rip rap. Both methods are often combined in the hopes that they’ll provide better seepage and erosion control when used together. Unfortunately, spray sealants tend to fail after just a few months, if they form a barrier at all. Layers of gravel and rock don’t stop seepage at all and only help erosion control to a certain degree. Avoid these ditch lining methods unless they’re the only options available in a remote area with limited access to better materials.
Good: Pre-formed and Poured in Place Concrete
Concrete has a long history of being used to line irrigation and drainage ditches. While you may see it in use across the country, it’s far from an ideal material for this purpose. The stiffness that gives concrete its strength also makes it prone to cracking when the soil below it shifts over time. Tiny cracks form in the concrete that are impossible or hard to spot, leading to leaks that go unnoticed for years. Pre-formed concrete liner sections reduce the work required for installation, but they’re heavy, expensive to transport, and tend to leak at the seams between sections. Pouring concrete in place is an expensive way to line a simple ditch. If you’re required by a state or county regulation to use concrete in your agricultural or drainage ditches, consider combining it with a flexible liner that can capture any water that makes it past the first layer.
Better: Pre-formed Plastic Liners
Thanks to slightly better impermeability and resistance to damage from shifting soil; pre-formed plastic sections are a better lining choice than concrete. Ditch liner sections are only available in limited sizes and shapes, requiring you to dig to fit the liner rather than fitting it to your existing channels or custom designs. There’s no option to customize these pre-formed liners in most cases. Like pre-formed concrete, these liners are also tricky to seal between sections and prone to leaking.
Best: Flexible Polymer Liners
For an impermeable liner that can fit into the smallest and largest ditches equally well, choose a flexible liner. Multi-layered RPE, in particular, is your best option for lining any kind of ditch. With some products lasting over 20 years under regular use conditions, maintenance is dramatically reduced so your team can spend more time on cleaning and repairing other parts of the system. Flexible liners are also lightweight and easy to transport to remote locations, even if bundles of the material must be carried by hand. If you choose the right material, constant UV and chemical exposure isn’t a problem either.
The best liner material for ditches remains the same whether you’re planning new construction or renovations of existing channels. Flexible liners adapt to the narrow width and steep slopes of small ditches without risking cracking or seam failure. If you’re ready to explore your options for flexible liners, get in touch with us here at BTL Liners today.