It is unlawful for any person to dig, break, excavate, tunnel, undermine, or in any manner break up any street or to make or cause to be made any excavation in or under the surface of any street, alley, sidewalk, or any other public grounds for any purpose, or to place, deposit, or leave any earth or any other excavation material obstructing or tending to interfere with the free use of such street, alley, sidewalk, or other public grounds unless such person shall first have obtained an excavation permit therefor from the superintendent of public works. (Ord. 280 § 1, 1969)