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Trench Backfill and Waste Rock Trench excavation for pipelines can unearth substantial quantities of stone and rock spoil from the various subsoil layers. It is important to restore the original soil profile and prevent either large rocks or concentrations of stone material used as backfill from obstructing normal farm tillage operations and disabling farm machinery. Also, if the backfilling phase is completed while there is water in the pipeline trench, long stretches of right-of-way with prolonged soil saturation conditions can occur. Such saturated soil conditions can result in significant restoration difficulties and delays. Standard: The pipeline trench should be thoroughly dewatered prior to backfilling. The trench should be backfilled with the excavated spoil material and compacted during backfilling to minimize trench settling. Topsoil should not be used as trench-backfill and should remain in its segregated stockpile until all deep ripping and stone removal work is completed. On agricultural land, blasted or excavated bedrock, boulders and concentrations of excavated stone or rock materials should not be returned to the trench any closer than 24 inches from the exposed work surface of the stripped portion of right-of-way. The remainder of the backfill should be limited to suitable subsoil material, backfilled up to the top of the exposed work surface. Excess waste rock/stone materials should be removed and disposed of safely. Deep Ripping and Stone Removal The dense compaction of the exposed subsoil (i.e., the spoil storage area, backfilled trench and construction work and traffic area) must be alleviated together with stone removal prior to the subsequent stages of topsoil replacement and final subsoil shattering. Standard: During periods of relatively low to moderate subsoil moisture, the exposed right-of-way shall be returned to rough grade; deep ripped with heavy duty ripper; and, alternately deep chiseled and rock-picked until uplifted stone/rock materials of four inches and larger size are cleaned off the site and disposed of properly. In subsoils with excessive stony-rocky material in the upper layer, an alternate ripping/stone removal plan should be developed and submitted to the Department of Agruculture and Markets for review in advance of project construction. Topsoil Replacement and Subsoil Shattering Standard: After the initial subsoil ripping, chiseling and stone removal has been completed, the segregated topsoil materials should be uniformly spread across the stripped portion of right-of- way. Topsoil spreading should be conducted only during periods of low to moderate soil moisture to avoid rutting, mixing and recompaction of the soil profile. Topsoil spreading should not be conducted during periods of saturation or frozen ground. Alternative plans should be prepared for suspension of topsoil spreading under such conditions, and soil restoration work should not resume until appropriate moisture conditions occur during the following season. After topsoil replacement, final subsoil shattering using a deep 4-shank paratill with narrow leg spacing should be conducted throughout the disturbed right-of-way to a depth of 18 inches. Large, uplifted rock materials should be picked from the surface and disposed of properly. Final subsoil shattering and rock removal should be conducted only during periods of low to moderate soil moisture and not during periods of saturation or frozen ground. Final subsoil