2020-03-24_PERMIT FILE - C1981019A (39)

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RULE 2 PERMITS Cienertc Cres-&action for Topsoil Replacement Depths Avows a Typroal Drainage O-IoA[Mope 0-1096 elope �y -:;" Channel a `i A Generally defined as a"thin"zone of topsoil(0"-6")exclusively applicable to Sagebrush Steppe areas which will ideally average 4 inches. Areas seeded using the grassland mix will almost always be>10%slope and have>6 inches of topsoil replaced. B Generally defined as a"thicker"(>6")zone of topsoil in the transition zones between Sagebrush Steppe areas and Grazingland areas where topsoil thickness will likely begin around six inches at slope breaks>10%and gradually increase to approximately 10-14 inches to the base of slopes with armored channels in all reclamation areas except South Taylor. South Taylor topsoil replacement depths will begin with approximately 6 inches at the top of slope breaks>10%and gradually increase to approximately 12-18 inches mid-slope up to potentially 3 to 4 feet down-slope to the base of slopes with armored channels,depending on slope length and topsoil balance considerations. C Generally defined as the area within armored channels that will receive minimal to no volume of topsoil due to the likelihood any topsoil placed within the structure would erode into terminal sediment control structures and be lost. On-site experience has demonstrated natural sedimentation processes will support vegetation early post construction,and these areas will be seeded via broadcast method to provide a seed source for beneficial species establishment. NOTE: Specific details regarding topsoil replacement depths on special planting areas will be included in the description provided for approval prior to the creation of those areas. The grazingland targeted reclamation blocks will by necessity have thicker layers of topsoil than recent reclamation areas due to reduced volume of topsoil that will be placed on sagebrush steppe areas. Unless Colowyo provides specific justification, the topsoil resource will be placed in a manner that is thin on the ridge tops and gradually increasing in depth to the base of coherent drainages. Large drainage bottom channels that will convey water on a consistent basis will receive little to no topsoil resource as any topsoil placed in these areas will likely be mobilized and washed down the drainage. The full application of seed will still be applied to these areas in order to minimize erosion and allow vegetation to establish in these special locations, adding an additional dimension of potential vegetation community diversity. Colowyo is moving away from applying topsoil in uniform layers and variability in depth will be applied in all practical locations to maximize plant community diversity in areas designated for grazingland. Because the volume of topsoil to be applied to sagebrush steppe targeted areas is much less, and the creation of a seedbed conducive for shrub establishment is of major importance,the variability of topsoil depths within these areas may be limited. However,wherever practical,Colowyo will also make attempts to vary topsoil depths in the Sagebrush Steppe areas as well. Colowyo will ensure proper topsoil resource management through annual analysis of the topsoil balance in stockpiles, the expected areas for the following year's reclamation focus, the total disturbance area, and the results of topsoil stripping activities each year. Because the topsoil resources from the "original" permit areas (East Pit, West Pit, Section 16, facilities, Gossard Loadout, etc.) are for the most part segregated by location from the topsoil generated from the South Taylor area,it will not be difficult to ensure that these resources are reapplied to the general areas from which they came. The same principles apply to both areas (original & South Taylor) regardless of targeted reclamation focus; 6 inches on ridge tops with variably deeper application down slopes to the bottom of coherent Rule 2 Permits 2.05-23 Revision Date: 12/20/19 Revision No.: TR-135