The department shall have one standard for the classification of great ponds and natural lakes and ponds less than 10 acres in size. Impoundments of rivers that are defined as great ponds pursuant to section 480-B are classified as GPA or as specifically provided in sections 467 and 468. [1989, c. 890, Pt. B, §64 (AMD); 1989, c. 890, Pt. A, §40 (AFF).]