Which of the following best describes the final cover or cap for a landfill?

The final cover, or cap, of a landfill is best described as layers of materials over a closed landfill designed to minimize rainwater infiltration. This multi-layered system typically consists of a geomembrane, geotextile, and soil or other materials that collectively serve several essential functions.

First, it prevents precipitation from entering the waste, thereby minimizing the potential for leachate production. By limiting the amount of water that can infiltrate the waste, these layers help control the environmental impacts associated with landfill operations, such as groundwater contamination.

Additionally, the cover supports vegetation growth, which can further stabilize the soil and prevent erosion, but the primary objective is to reduce moisture infiltration and manage the landfill's environmental footprint effectively. This is critical in the long-term management of the landfill site, ensuring it meets regulatory standards and protects surrounding ecosystems.

Options that suggest a single layer of topsoil or temporary covers do not capture the complexity or the main objectives of a landfill cap, while systems aimed solely at reducing leachate production do not encompass the comprehensive design of a final cover.