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Just how thick is a 60 mil liner? Details About Groundwater & Containment Systems

The Riverview Land Preserve (RLP) sits on top of a solid clay foundation. Clay will not let rain or other water pass through it into the ground. Groundwater is down in the bedrock, about 50-feet deep well under the land preserve and under the clay shield. The groundwater is also protected by a thick bottom liner. This liner collects any rain or liquid that settles down from the waste into the preserve. That liquid is then funneled into a collection system where it is disposed of properly. 

How thick is the liner? The liner is about 60 mils thick. That is about 0.063 inches. What does this compare to?  An automobile fender or hood on your car is not that thick. It is only 0.0478 inches.  The credit and debit cards we use every day are 30 mils thick or 0.03 inches. The liner used in the land preserve is twice as thick as a credit card and over 50 percent thicker than your car fender you rely upon to keep you safe. That’s a lot of protection to the environment and the groundwater in the City.

By the way, did you know that Riverview’s groundwater contains naturally occurring sulfur?  This fact alone makes it unsuitable for human use. Thus, everyone in the City and surrounding communities use municipal water.

As far as the law is concerned, modern landfills are required to have a liner system meeting specific barrier requirements, typically a polyethylene plastic with soil barriers to contain contaminants. All landfills can leak, unfortunately that is true.

“The typical requirements for secondary containment (the second liner system) is 3 feet (or equivalent) of 10-7 cm/sec clay (that is 0.0000001 cm/sec). Riverview has more than 10 feet of clay between the bottom of the landfill and the bedrock groundwater,” according to Jennifer Bowyer, TetraTech engineer. “Just doing straight math, it would take over 25 years for contamination to get through 3 feet of clay, and about 75 years through 10 feet. A leak would then have to travel horizontally through the groundwater, first encountering the perimeter monitoring network (installed per regulation) and then on to a public body of water. RLP team members measure and report quarterly groundwater flow to be about 200 feet per year. The Detroit River is 9,000 feet away, so it would take over 45 years to reach the river.” The perimeter monitoring network would detect contaminants well before they even could leave the landfill property itself.

The polyethylene plastic liner is 60-mils (60-thousandths of an inch) thick and very durable. “How can they say that 60-mil thick plastic in liners and covers will disintegrate and fall apart, but a 0.5-mil grocery bag supposedly will last for a thousand years in the same conditions?” Bowyer said. “These liner materials have been tested and are guaranteed/certified for 100 years. Testing, however, shows that 100 years will not make a significant deterioration in their performance. These installed materials are only 40-60 years old at present, so testing cannot even get to the end of the lifespan at this point.”

It should be noted that as organizations like the Conservation Law Foundation (CLF) help to close or impede East Coast landfills, and to be clear: That displaced East Coast waste will come West – and it already has due to onerous regulation costs out East that have made it cheaper to transport waste 1,000 miles than to use a local landfill. RLP does not currently – and will not - accept waste from the East Coast, but CLF is not really doing Michiganders and Midwesterners any favors.

RLP is regulated by three different offices of the Michigan Department of Environmental, Great Lakes, and Energy, as well as the Wayne County Department of Public Services and the United States Environmental Protection Agency. The RLP team operates a safe landfill under the strictest state and federal standards. And, RLP conducts daily, weekly and monthly inspections of all the control systems, and is inspected regularly by regulatory agencies.

Learn more about RLP at riverviewlandpreserve.com or reach out and ask us for more detail - riverviewlandpreserve.com/contact-us.