Backfilling in any street opened or excavated pursuant to an excavation permit issued hereunder shall be compacted to a degree consistent with that of the undisturbed ground in which the trench was dug. Compacting shall be done by manual or mechanical tampers or vibrators, by rolling in layers, or by water settling as required by the soil in question and sound engineering practices. Fine material reasonably free from lumps and stones, selected from the spoil, shall be thoroughly compacted around and under the substructure to the upper level of such substructure. Above the upper level of the substructure, backfill material shall be placed to the subgrade of the pavement in lifts consistent with the type of soil involved. Broken pavement, large stones, roots, and other debris shall not be used in the backfill. (Ord. 119 § 1(1019), 1969).