Any permit and plan is valid for 2 years after it is issued. The Director may extend any permit or plan for 1 year if a permittee so requests. The Director may impose an additional standard or requirement as part of any extension. The Director may require a plan modification as part of any extension. (1976 L.M.C., ch. 14, § 1; 1984 L.M.C., ch. 24, § 20; 1986 L.M.C., ch. 45, § 1; 2013 L.M.C., ch. 9, § 1.)