What is one requirement the final cover system must meet regarding permeability?

The final cover system at a landfill must meet specific permeability requirements to ensure effective containment and minimize the potential for leachate migration. The correct response emphasizes that the permeability of the final cover system should be less than or equal to that of the bottom liner system or no greater than 1x10^-5 cm/sec.

This requirement is crucial for several reasons. Firstly, maintaining a low permeability ensures that rainwater and other precipitation do not infiltrate the waste material, which could lead to increased leachate production and potential contamination of groundwater. By comparing it to the bottom liner system, the regulation emphasizes the effectiveness of both layers in preventing water movement, thereby enhancing the overall leachate management strategy.

Furthermore, the specific permeability threshold of 1x10^-5 cm/sec serves as a standard that balances environmental protection with engineering practicality. It ensures that the final cover effectively limits the flow of water while allowing for proper drainage and soil stabilization, thus contributing to the long-term integrity of the landfill.