Section 17. Whoever wilfully and without lawful authority or license therefor, deposits in a harbor or other navigable tide waters stones, gravel, mud, ballast, cinders, ashes, dirt or any other substance, tending to injure the navigation or to shoal the depth thereof, or throws or drops into such waters any barrel, box, log, timber or other object, tending to obstruct the navigation thereof, shall be punished by a fine of not less than twenty nor more than one hundred dollars.