SBCT Final EIS - Govsupport.us

Chapter 5 – Environmental Consequencesby military training activities often occur in extremely elevated numbers and intervals, therebycausing unacceptable damage to critical vegetative cover that aids in stabilizing soils from wind andwater erosion. FTC’s fire management program considers these effects in decisions regarding wildfiresuppression and prescribed burning as they relate to mandates to provide for military training whilestriving to maintain a vital, developing, and diverse ecosystem. Generally, FTC uses prescribed firesto reduce natural fuels on the range. If the fuels are not controlled, rangeland wildfires may get out ofcontrol. Impacts associated with soil erosion resulting from wildland fires caused by trainingactivities on FTC are expected because of the arid climate, often-dry vegetation conditions, andoccurrence of electrical storms.Regulatory and Administrative Mitigation 4: The impact is considered less than significant withimplementation of the mitigation measures described above and detailed in the FTC INRMP(DECAM 2002b). Continued implementation of the Prescribed Burn Plan will create buffer zoneswhere required, thereby reducing the potential extent of an accidentally ignited wildfire.Less than Significant ImpactsExposure to Soil Contaminants. Munitions are fired from firing points downrange and into the rangeimpact areas. Public access to these areas would be restricted because of the explosives risk to humansafety. The impact associated with exposure to munitions soil contamination during live-fire trainingon FTC is considered less than significant because military personnel or public contact withdownrange, impacted soil is unlikely and there are relatively few areas with high levels of widespreadexisting chemical constituent concentrations. Additionally, as described for cantonment and rangeconstruction, selenium study results provide FTC managers with site-specific selenium knowledge.Resulting management decisions ensure that land user activities do not create a seleniumenvironmental reception hazard.Seismic Hazards. Similar to cantonment and range construction, live-fire training on the two newranges on FTC is not expected to have any effect on the frequency of earthquakes; therefore, theimpact would be the hazards associated with training occurring in areas in which seismic hazardsexist. There is low potential for significant seismic activity near the ranges. Range structures wouldlikely be designed to withstand the expected range of seismic shaking, and the impact is consideredless than significant.5.4.2.4 Impacts from Maneuver TrainingSignificant ImpactsImpact 5: Soil Erosion. Maneuver training would occur on both FTC and PCMS. Compared to theexisting IBCT training, Alternative C would intensify maneuver training by approximately doublingthe MIMs at the existing ranges at both FTC and PCMS (49,576 MIMs associated with the IBCTversus 104,898 MIMs associated with the SBCT). Additionally, the frequency and intensity of smallunit (squad, platoon, and company) maneuver training at FTC would increase by about 50 percentcompared to the existing IBCT training. Mounted and unmounted maneuver training using Strykervehicles is expected to damage or remove vegetation and disturb soils to an extent that wouldsubstantially increase soil erosion rates and alter drainage patterns in the training areas, which couldlead to gullying, and indirectly to downstream sedimentation, particularly when the vehicles traveloff-road. Over all, given the qualitative differences between the ways the two types of units train,surface disturbance created by IBCT training and SBCT training is relatively comparable and bothcan lead to long-term significant soil erosion.February 2008 5-136 2/25th SBCT Final EIS