Paragraph 31 I1

After the purpose of any temporary tidal work has been accomplished or after a reasonable period of notice in writing from the Port Authority requiring it so to do, the undertaker shall with all reasonable dispatch, remove that work or any materials relating thereto which may have been placed below the level of high water by or on behalf of the undertaker and, on its failing so to do within a reasonable period after receiving such notice, the Port Authority may remove the same and charge the undertaker with the reasonable expense of so doing, which expense the undertaker shall repay to the Port Authority.