Upon the nullification, expiration, or revocation of a license, the licensee shall remove all structures authorized in such previous license which are located:

1. (1) below the high water mark, unless the Department determines that continued existence of said structures will promote the public interests served by M.G.L. c. 91;
2. (2) above the high water mark, if the Department determines that continued existence of said structures will have a significant adverse effect on the public interests served by M.G.L. c. 91. Such removal shall take place upon written notice to and at the direction of the Department.