SBCT Final EIS - Govsupport.us

Chapter 5 – Environmental ConsequencesImpact 2: Soil Erosion from Wildland Fires. Continued use of Army ranges for live-fire trainingwould prolong the threat of accidentally ignited wildfires, which could lead to increased soil erosion.Regulatory Administrative Mitigation 2: The IWFMP, its Fire Management Areas, and wildland fireSOPs would continue to be followed. The impact would continue to be significant but mitigable toless than significant.Less Than Significant ImpactsExposure to Soil Contaminants. Live-fire training would be conducted at the same frequencies andintensities described in the 2004 EIS on existing range facilities. As described for Alternative A,munitions fired from firing points are directed downrange into the 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 that military personnel or off-post residents would encounter the constituentsof these munitions in the downrange impact area soils. The risk to military personnel who use theranges would be low because contact with downrange impacted soils is unlikely and there arerelatively few areas with high chemical constituent concentrations. There would be no risk to thegeneral public from munitions constituents related to range use because there would be no publicaccess to these areas. Exposure to soil contaminants during live-fire training activities is considered aless than significant impact.Volcanic and Seismic Hazards. As described for Alternative A, portions of the areas that would beused for live-fire training are subject to volcanic eruptions, lava flows, occasional explosiveeruptions, volcanic gas venting, and earthquakes. The impact would be the hazards to personnelassociated with weapons training in areas in which volcanic and seismic hazards exist. On Oahu, theexpected intensity of ground shaking in a reasonably strong earthquake would be moderate to minorbecause of its distance from the source of the earthquakes. There is very little risk of renewedvolcanic activity on Oahu, so the hazards to personnel on the ranges on Oahu are considered less thansignificant. Existing warning systems are generally expected to provide sufficient warning of avolcanic eruption near PTA, such that personnel and equipment would likely have time to evacuatefrom the path of a lava flow. The hazards associated with lava flows or earthquakes at PTA are alsoconsidered less than significant.5.5.2.1.4 Impacts from Maneuver TrainingSignificant Impacts Mitigable To Less Than SignificantImpact 3: Soil Erosion. Maneuver training would continue using the equipment and training methodsemployed by the 2/25 th ID (L). Newly acquired lands at WPAA and SRAA would not be used formaneuver training. Training activities, including the use of military vehicles on unimproved roadsand off-road areas, would result in localized significant soil erosion, particularly in areas underlain byHelemano soils on steep slopes adjacent to streams or gulches. Training activities impair vegetationgrowth, resulting in gully erosion, which increases in severity as the gullies broaden. This erosion canremove large volumes of soil, which are ultimately deposited downslope or downstream.Under the No Action alternative, some of the existing erosional problems at KTA result from publicaccess to portions of KTA and to unauthorized activities, such as off-road vehicle use and motocrossriding on informal trails adjacent to the motocross raceway. Public use represents a source ofpotentially significant soil erosion impacts that are comparable to military off-road impacts on soils.These impacts represent a potentially significant baseline impact on soil erosion.February 2008 5-196 2/25th SBCT Final EIS