SBCT Final EIS - Govsupport.us

Chapter 5 – Environmental Consequencesstandard range maintenance measures such as road grading, target repair, and berm recontouringwould also reduce erosion. Implementation of standard construction BMPs and the land managementpractices specified in the FTC INRMP and ITAM annual work plan would reduce soil erosion fromrange construction to less than significant levels.Less than Significant ImpactsExposure to Soil Contaminants. Impacts associated with potential exposure to soil contaminantsduring range construction activities on FTC would be less than significant. As described forcantonment construction, FTC managers operate with site-specific selenium knowledge. Resultingmanagement decisions ensure that land user activities do not create a selenium environmentalreception hazard.Seismic Hazards. Similar to cantonment construction, construction of the new ranges on FTC are notexpected to have any effect on the frequency of earthquakes; therefore, the impact would be thehazards associated with the ranges being constructed in areas in which volcanic and seismic hazardsexist. As described for cantonment construction, there is low potential for significant seismic activityin the vicinity of the ranges. New structures would likely be designed to withstand the expected rangeof seismic shaking; therefore, the impact is considered less than significant.5.4.2.3 Impacts from Live-Fire TrainingSignificant Impacts Mitigable to Less than SignificantImpact 3: Soil Erosion and Compaction from Munitions Impact. A larger number of Soldiers woulduse existing and new ranges for live-fire training on FTC. There would be a corresponding increase inthe total number of rounds fired (estimated to be 88 percent), as well as increased vehicular traffic.While some live-fire training would occur in existing impact areas, the frequency of weapons trainingis expected to increase. Also, other training would occur on the new ranges and the intensity of thetraining events at existing ranges, such as the DMPRC, would increase. Surface disturbance causedby munitions impact would result in larger areas of bare ground than observed under currentconditions. Munitions impact can directly create craters and remove patches of vegetation, whichnormally protects soil from erosion by slowing runoff, intercepting raindrops before they reach thesoil surface, and anchoring the soil. Compaction in the craters caused by larger ordnance explosionscan alter the permeability and water-holding capacity of the soils and harden silty clays affecting theability of vegetation to recover in those areas. These direct impacts create large areas of bare groundand exposed soils that are susceptible to wind and water erosion, which can indirectly cause removaland deposition of soils, gullying, or instability of soils in areas of steep slopes and rapid runoff.Although weapons training events would be periodic, long-term impacts are expected because soildisturbance typically requires time and effort to amend.Regulatory and Administrative Mitigation 3: Implementation of standard BMPs, as well asrevegetation and other land restoration projects implemented by the LRAM, TRI, and SRA programsof the FTC INRMP and ITAM annual work plan (described previously) would reduce these impactsto less than significant.Impact 4: Soil Erosion Resulting from Wildland Fires: There would be an increase in the totalnumber of rounds fired at new and existing ranges on FTC, as well as increased vehicular traffic. Anincreased risk of accidental wildfire ignition would come from ordnance, vehicles, flammablematerials, or cigarettes, which could lead to subsequent large areas of bare soils susceptible toerosion. While wildfire is considered a necessary component of a healthy ecosystem, fires generatedFebruary 2008 5-135 2/25th SBCT Final EIS