What type of soil is most desirable as a landfill cover?

The most desirable type of soil as a landfill cover is sandy loam due to its balanced properties that provide both drainage and moisture retention. Sandy loam has a mixture of sand, silt, and clay, which allows it to manage water effectively while also reducing the risk of contamination by preventing leachate from draining too quickly into the surrounding environment.

This soil composition aids in vegetation growth, which can further stabilize the surface of the landfill and minimize erosion. Additionally, sandy loam's structure contributes to an optimal balance of air and water, supporting the microbial activity necessary for any potential biological processes occurring within the landfill site.

In contrast, clay tends to retain water and can create a barrier that may not facilitate gas release effectively, potentially leading to issues with odor and pressure buildup. Sand, while offering good drainage properties, lacks the finer particles needed to hold moisture and nutrients. Gravel, being highly porous, allows water to flow through very quickly, which is not ideal for landfill cover as it does not retain moisture or support the growth of vegetation effectively. Therefore, sandy loam presents an advantageous choice among landfill cover materials.