|Thursday Techniques: Pond Liners| |Written by Heleigh Bostwick
Thursday, 09 August 2012| When you construct a pond, it’s
necessary to use a pond liner, whether it’s a type of plastic
such as polyvinyl chloride (PVC) or high-density polyethylene,
or a layer of bentonite clay. Pond liners line the pond forming
an impervious barrier between the soil and the water so water
doesn’t seep into the soil. Environmentally speaking, the choice
of liner would naturally be bentonite clay, even if the pond is
quite large or very small. There are two types of bentonite
clay, sodium bentonite and calcium bentonite but only sodium
bentonite swells on average to approximately 15 times its size
when exposed to water. During the swelling process, the clay
forms a tight bond with the underlying soil. As a clay soil,
bentonite is naturally impervious but does have its problems if
the clay layer, typically 2 to 4 inches thick, is not properly
compacted during the construction phase. Clay particles are very
fine and wind during sto