No person shall destroy, injure or remove any monument erected or placed by the city engineer, provided, if it becomes necessary for any person, in pursuit of any lawful purpose to have any such monument removed, notice of such necessity must be given to the city engineer, who shall proceed forthwith, at the cost of the person requiring such removal, to remove such monument, and replace the same in its original position, as soon as the object shall be attained, for which the removal shall have been made. (Ord. 46 CS §17; prior code §21.15.)