Storm water retention requires runoff is held for a specific period of time, to give sediment a chance to settle. This is generally a 12-hour window, which means that every gallon of water entering the pond needs to remain in it for 12 hours or more before evaporating, seeping out, or flowing through an outlet. Retention ponds with advanced wastewater treatment features may need to hold water longer periods to give nutrients and chemicals a chance to process through natural bacterial colonies. Liners play an essential role in preventing water from seeping through the soil faster than intended and therefore causing flooding and contamination issues. Yet, not all flexible and permanent liners will work for retention pond applications.
Best Materials for Pond Liners
When considering the many types of flexible geomembranes available on the market for pond lining, it easily becomes overwhelming to compare their various features. However, selecting a material is easier than you think. Reinforced polyethylene (RPE) offers the best combination of chemical resistance, light weight, durability, UV resistance, easy installation and fish-safe features on the market. BTL’s AquaArmor is the perfect product line to meet your needs. Take a look at the AquaArmor PP-45, RPEL-30 and BTL-40 to see which liner will work best for your retention pond. These liners are pliable and strong and can be quickly installed with a small crew; making them the perfect choice.
How to Seal Seams
PVC is a popular material for some types of ponds, but it’s not ideal for retention ponds since it relies on messy glues to seal the seams between pieces of liner. EDPM is also less than ideal due to the use of adhesive seam tapes that make it easy to miss a spot and develop a serious leak. RPE, HDPE, and LDPE liners can all undergo heat welding to permanently seal overlapping pieces of liner together. This process is much quicker and more reliable than any glue or tape method. If there’s a need for a patch or repair later when a tear or loose seam is discovered, heat welding makes quick work of it. Look for liners that can be custom manufactured in large sizes, to fit your specific project specifications. This will dramatically simplify the installation process.
The liner installation process brings many risks of damage to a low-quality pond liner. Less durable materials like PVC often snag on buried rocks and roots in the ground and develop tears that are hard to spot once the material is smoothed down. The reinforcements in RPE liners prevent this from happening. Since most retention ponds do best when planted, you’ll need to pick a quality liner, such as the industry leading products offered by BTL, that won’t tear or collapse from being covered with dirt.
Concrete and Geomembranes
Some retention ponds require concrete lining to function as needed. Yet, concrete on its own is a less than ideal lining material for any pond. Despite appearing to be watertight, the surface of concrete is full of tiny pores that slowly allow water to travel through the material through capillary action. Sealing the concrete prevents this effect for a few months or years, but sealants always eventually wear off. The better choice is to lay down an impermeable layer of geomembrane before pouring any concrete for your retention pond. If water does seep through the concrete, or through tiny cracks that inevitably form over time, the geomembrane will stop the water before it soaks into the ground.
If you are still wondering which pond liner is best for a challenging retention pond project, we’re happy to help here at BTL Liners. Contact us for advice on the best liner material for your needs.