SBCT Final EIS - Govsupport.us

Chapter 5 – Environmental Consequences• Locate operational areas within hardwood forests (i.e., not in black spruce) to minimize the riskof wildfire.• Create defensible space around existing and new structures. This would be done by clearing fuelsaround new structures and facilities to reduce the threat to structures.Exposure to Soil Contaminants. Low levels of explosive residues are associated with munitions use.Studies have shown that TNT residue is readily metabolized by soil microbes and the byproducts bindto organic matter. Areas with higher organic matter content appear to bind residues more rapidly. Theexplosive residues RDX and HMX do not degrade rapidly and are not very soluble. However, oncedissolved in water, both can be highly mobile in soil. RDX and HMX are not expected to be easilymobilized because of low precipitation and frozen conditions most of the year. Additionally, strongreducing conditions found in the soils of some wetland impact areas in Alaska readily degrade RDXand HMX (USARAK 2004).Munitions are fired from firing points downrange and into the range impact areas. The Army restrictsaccess to these areas by Soldiers or members of the public because of the explosive risk to safety theyrepresent. It is unlikely; therefore, that military personnel or off-post residents would come intocontact with the constituents of these munitions in the downrange impact area soils. The risk tomilitary personnel who use the ranges would be low because contact with downrange impacted soilsis unlikely and there are relatively few areas with high chemical constituent concentrations. Therewould be no risk to the general public from munitions constituents related to range use because therewould be no public access to these areas. Exposure to soil contaminants during live-fire trainingactivities is considered a less than significant impact.Volcanic and Seismic Hazards. Similar to cantonment and range construction, live-fire training is notexpected to have any effect on the frequency of volcanic eruptions or earthquakes; therefore, theimpact would be the hazards associated with the training occurring on ranges in areas in whichvolcanic and seismic hazards exist. The impacts associated with seismic and volcanic hazards duringlive-fire training are considered less than significant because existing warning systems are generallyexpected to provide sufficient warning of an earthquake or eruption such that personnel andequipment would likely have time to evacuate.5.3.2.4 Impacts from Maneuver TrainingSignificant Impacts Mitigable To Less Than SignificantImpact 4: Soil Erosion Resulting from Maneuver Training Activities. Maneuver training would occurat both FRA and DTA in existing maneuver areas. Alternative B would add SBCT maneuver trainingto the new ranges at FRA. Additionally, the frequency and intensity of small unit (squad and platoon)maneuver training at FRA would increase compared to the existing IBCT training. Currently, anSBCT is stationed at Fort Wainwright and trains at DTA, so Alternative B would just add additionalSBCT troops and vehicle maneuver training there.Mounted and unmounted maneuver training using Stryker vehicles is expected to damage or removevegetation and disturb soils to an extent that would substantially increase soil erosion rates and alterdrainage patterns in the training areas. This could lead to gullying, and indirectly to downstreamsedimentation, particularly when the vehicles travel off-road. The Stryker vehicles are much heavierthan IBCT vehicles, and there would be increased numbers of vehicles with conversion from IBCTtraining to SBCT training, which would likely cause greater surface disturbance for the off-roadmaneuvering. Unlike the existing IBCT maneuver training, however, SBCT vehicles typically travelmore on roads than cross-country. IBCT maneuver training tends to cause additional surfaceFebruary 2008 5-77 2/25th SBCT Final EIS