How to Waterproof a Pond

Keep water in your pond

Ponds must be able to hold water in order to sustain a biologically diverse ecosystem for plants, fish, birds and aquatic animals to thrive. However, it is not uncommon for concrete ponds to develop cracks over time and slowly leak water into the soil below. It is imperative that the leak be repaired as soon as possible as water can exacerbate the problem.

Things You'll Need

• Pond liner
• Utility knife
• Decorative stonework
• Bentonite-based pond sealant
• Cup
• Granular spreader
• Water pump
• Fish

Instructions

1. Ensure your pond basin is completely dry and free of any sticks or stones that could puncture a hole in the pond liner or create gaps in the sealant.

2. Lay the pond liner in the bottom of the pond. Cut a hole in the liner to expose the drain if necessary. The liner should lay over the edges of the pond by at least one foot. Lay down decorative stones to hold the liner in place. Stack stones to create fish structures in the pond, if desired.

3. Spread a 1/4- to 3/4-inch-thick layer of Bentonite-based pond sealant over the pond liner with a cup or granular spreader to achieve the proper layering. This sealant provides extra protection to the liner.

4. Fill the pond with the submersible or inline pump. As water comes in contact with the Bentonite-based sealant, the individual granules form a cohesive mat to seal the bottom of the pond.

5. 

   Largemouth bass

   Stock the pond with the fish and other aquatic animals. If your managing a decorative pond, koi and goldfish are typical. If it's a fishing pond you're after, stock freshwater game fish like bluegill and largemouth bass.

References

• Aqua Blok: PondSeal
• National Resources Conservation Service: Backyard Pond