After a landfill is closed, how much soil should ideally be placed on top of the site?

The recommended amount of cover soil to be placed on top of a closed landfill is typically two feet. This is based on the need to ensure that the site is stable, provides adequate drainage, and minimizes the risk of erosion or settlement over time. A two-foot layer helps to create a barrier that can reduce the potential for water infiltration, which is critical in minimizing leachate production and protecting the surrounding environment. Additionally, this depth allows for vegetation to grow, which can further aid in preventing soil erosion and enhancing the site’s aesthetic value.

Covering a landfill with six inches would not provide sufficient protection or stability, as it could lead to issues with erosion and insufficient support for vegetation. Conversely, placing four feet of soil would not only be excessive but could also lead to unnecessary compaction and weight issues. Lastly, placing as much soil as available does not follow the best practices established by environmental regulations and engineering standards, as it does not ensure proper cover design and site management. Thus, the two feet of cover is the most appropriate and commonly recommended practice.