(a) Where there are practical difficulties or unnecessary hardships in carrying out the restrictions and standards set forth in section 577.6 of this Part, or the terms and conditions of an approved land management plan, the agency may, after public hearing, vary or modify the application of such provisions so that the spirit of the provisions shall be observed, public safety and welfare secured and substantial justice done.

(b) The procedures governing the agency's review of application for variances from the provisions of this Part, and public hearings thereon, shall be:

(c) A request for a variance to an approved land management plan administered by a local government shall be submitted to the local government, which shall apply in its decision the criteria set forth in this section for the consideration of variances by the agency.

(d) Upon receipt of an application for a variance from any provision of an approved land management plan administered by a local government, the local government body or officer having jurisdiction shall give written notice to the agency. If such variance is granted, it shall not take effect for 30 days after it is granted. If, within such 30-day period, the agency determines that such variance was not based upon the appropriate basis of practical difficulties or unnecessary hardships, the agency may reverse the local determination.