Alternative liner designs, which for Type I landfills must include a leachate management system, may be authorized by the executive director if the owner or operator provides a demonstration by computerized design modeling that the maximum contaminant levels detailed in §330.331 of this title (relating to Design Criteria), Table 1 will not be exceeded at the point of compliance. At the discretion of the executive director, a field demonstration may be required to prove the practicality and performance capabilities of an alternative liner design.