Trying to decide how to prevent a pond or lake from leaking can be a daunting process. When it comes to geomembrane liners there are many choices to consider. Type of liner material, thickness, reinforced, unreinforced, among other physical characteristics you may not understand. Why not just choose clay and be done with it? There are several reasons why this most likely is not the best choice and may have you purchasing a liner down the line after the clay has not worked as you had hoped. A couple of the main reasons are below.
- Clay or bentonite almost never comes with a warranty. Pond & lake liner geomembranes almost always do come with a long term warranty as well as an installation warranty to guarantee that your pond will be leak free. It is sad to have to work with someone who has invested so much in a clay liner only to have to purchase a geomembrane liner to cover the clay. Many liner projects are done after clay has been tried, and often times the liner was cheaper than the clay was!
- In many, if not most instances, clay leaks quite a bit. It can be very difficult (or impossible in some situations) to spread clay correctly so that there is no possibility of a major leak. Several factors are involved in making a clay liner fairly leak proof (they are never totally impermeable) which has to do with the soil it is being spread on, the slope of the pond, how evenly it is spread, the exact formula of the clay etc. Also, many times the clay has to be administered several times over the years to ensure that leaks are limited even if the clay is initially effective.
- Even if the clay does work, it is almost always less impermeable (leak proof) than a standard pond liner. The U.S. government had so many problems with clay liners in many situations they tried to ban clay and bentonite from being used. Many government entities have found a way to preclude clay by requiring at least 1 x 10^-7 impermeability (this equation shows the allowable leak rate approved.) Most liner materials are at least 1 x 10^-10 to -12. Meaning that the standard geomembrane liner is 1,000 to 100,000 times more leak proof then clay!
- Many well known Geomembrane Liner companies have been around for 25 years or longer with a proven track history. Clay is used for different applications and is not normally specifically used for ponds or lakes so there is often no good guidance or help with your new pond especially a few years down the line when you are having trouble with your pond and the clay company may no longer exist or has moved on to different industries.
- In most cases a geomembrane liner is actually more affordable than clay. Clay can be very expensive to transport to the site and also difficult and time consuming to install. When this is all factored as much as 90% of the time clay is more expensive than affordable liner alternatives.
These are just a few reasons why clay is not normally the best option. These reasons are why geomembrane liners are the preferred containment option for ponds and lakes throughout the United States.