2008-02-22_APPLICATION CORRESPONDENCE - C2008086 (39)

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CHAPTERFOUR Environmental Consequences and Mitigation 4.2.5 Soils No Action Alternative Under the No Action Alternative, the proposed project would not occur. Coal removal and the associated disturbance and impacts to soils would not occur on the additional acres of the lease. Proposed Action Alternative Potential soil issues in the project area may include: • Highly saline and shallow soils, which may be difficult to re-vegetate. • Landslides. • Expansive soils. • Corrosive soils. • Erosive soils; some soils are slowly permeable and concentrate run-off during storm events. • Soils derived from Mancos shale tend to be very sticky and slippery; unimproved roads may be impassable when wet. • Potential impacts to prime farmland south of the Highline Canal. • Potential impacts to biological soil crusts. Some soils are prone to landslides and active erosion on steep slopes, indicated by gullying and piping processes. Some soils in the project area have moderate to high expansive (high shrink- swell) properties and may contain evaporite minerals that are corrosive to conventional concrete and metal pipes. When wet, soils derived from Mancos shale become sticky and slippery, making unimproved roads virtually impassable. Saline or sodic soils may be difficult to stabilize and revegetate upon completion of construction activities, particularly on slopes. The Grand Junction RMP lists these criteria to identify management areas and potential impacts of planned actions of the project: 1. Suitability of the soil to support the project (or the soil limitations that may lessen or prevent the project's success). 2. Special safety hazards associated with particular soils or soil characteristics (i.e., slumping or mass movement). 3. Critical erosion areas in which land treatments or other practices have a high probability of reducing soil loss and degradation of water quality. 4. Slopes over 40 percent, as the susceptibility to accelerated erosion and mass movement are great. Removal and replacement of soils during mining and reclamation would cause changes in the soil resources. In reclaimed areas, soil chemistry and soil nutrient distribution would generally be more uniform and average soil quality would be improved, because soil material that is not suitable to support plant growth would not be salvaged for use in reclamation. This would result in more uniform vegetative productivity on the reclaimed land. The replaced soil would support 4-76 DBMS 631