All spaces excavated and not occupied by abutments, piers or other permanent work must be refilled with earth up to the surface of the surrounding ground. Where the backfill is to carry the roadway embankment or any part thereof, the backfill shall be made in continuous horizontal layers not greater than eight inches (8") in thickness, and each layer shall be thoroughly compacted by tamping by a method approved by the city before the succeeding layer is placed and the same for an approach to embankment to bridges and culverts. All other backfill shall be thoroughly compacted and its top surface shall be neatly graded. All material used for backfill shall be of a quality acceptable to the public works director and shall be free from large or frozen lumps, wood or other extraneous material. In general, this material shall be selected from the material excavated in connection with the substructure involved. Jetting or ponding of the backfill will not be permitted unless specifically authorized by the city engineer, in which case mechanical tamping will be required. All aspects of backfilling must comply with city street construction standards. (Ord. 3013, 2-14-2005)