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A typical landfill design utilizes a soil layer with vegetation on top as the erosion layer. This layer acts as an erosion control, reducing water infiltration through evapotranspiration and providing nutrients for vegetation growth.

Below this is the infiltration layer, also known as the "low permeability" layer. This layer, installed above the solid waste, employs low permeability materials to minimize water infiltration into the waste. For this specific study, the RCRA does not require a composite system for this layer as long as the permeability requirement (K < 1 × 10−5 cm/s) is met.

Ideally, a drainage layer and a filter layer are placed between the topsoil and the infiltration layer. The drainage layer, angled for gravitational drainage, removes water that infiltrates through the topsoil, reducing the amount reaching the infiltration layer. The drainage layer's discharge occurs at the landfill flanks and toe. To prevent clogging, a filter layer (geosynthetic fabric or sand) traps soil fines from the topsoil, preventing them from clogging the drain.

Typically, a soil layer with vegetation on top is utilized as the uppermost erosion layer. The vegetation serves as erosion control and reduces water infiltration by evapotranspiration, while the soil layer serves as a protective layer and
the nutrition source for vegetation growth (Shanahan, 2004).
The infiltration layer is also termed as the “low permeability” layer and is installed above the solid waste and utilizes low permeability materials to prevent or
minimize water infiltration into the solid waste (Figure 2). For the specific site
in this study, the RCRA does not require a composite system for this layer, provided that the permeability requirement is met (K < 1 × 10−5 cm/s).
Ideally, a drainage layer and a filter layer are installed between the topsoil layer and the infiltration layer (Figure 2). By gravitationally draining away water
that has infiltrated through the upper soil, the amount of rainwater seeping
down onto the infiltration layer is reduced. The drainage layer is usually constructed at an angle to utilize gravity for drainage, and the fluid is discharged
along the landfill flanks and to the toe. To prevent the drainage layer from clogging, the filter layer that is normally made of geosynthetic filter fabric or sand
filters out the soil fines coming from the soil layer, which could potentially clog
the drain