The disposal units shall include an engineered cover. The design goal for the cover shall be to prevent water infiltration. The cover shall be designed to:
- (1) Provide long term stability without the need for active maintenance. The engineered cover shall perform through the long term care period.
- (2) Direct surface runoff away from the disposal unit.
- (3) Minimize erosion, differential settlement, ponding, piping, mass wasting and slumping.