All trenches and excavations shall be backfilled in the manner provided in this Section. The trench or excavation shall be filled to not less than one foot (1') above the top of the pipe or other utility facility with fine material selected from the excavation, free from stones and lumps and of such character as to be readily compacted around and under the pipe or other utility facility, or with an imported fine granular material wherever material from the excavation is not suitable. The backfill material shall be thoroughly compacted around the pipe or other utility facility. Above the resultant level of this first operation the trench or excavation shall be backfilled with earth from the trench excavation or with imported material to six inches (6") below the subgrade of the curb, gutter, pavement, sidewalk or driveway to be replaced or to the surface if no improvement replacement is indicated. The use of water in this stage of the backfill operation will not be permitted if the soil will not readily drain and/or if the adjacent street may become damaged or the paving is unduly delayed. If the material from the excavation will not give the required relative compaction, an imported granular material that will give the relative compaction shall be used. Excess water must be evaporated before the next layer of earth or paving is placed. If an improvement replacement is indicated, the upper six inches (6") of the trench immediately below the subgrade of the improvement to be replaced shall be filled with selected imported granular material of such character as to readily compact by sprinkling with water if too dry to tamp and thoroughly compacted by power-driven equipment. All work shall be done in such a manner as to obtain a relative compaction throughout the entire depth of the backfill of not less than that which exists adjacent to the excavation, but in every case the work shall be done in such a manner as to obtain a relative compaction of not less than eighty percent (80%). (prior code §9-11-11)