SBCT Final EIS - Govsupport.us

Chapter 5 – Environmental Consequencessedimentation from areas downflow of the impervious surfaces. These impacts are considered longtermdue to the ongoing nature of such impacts. Use of ORVs has impacted area soils and permafrostin the form of erosion and rutting.Seismic or volcanic eruption hazards could result in cumulative effects if, for example, evacuation ofpersonnel or treatment of casualties were to overwhelm the capacity of the available infrastructure.The most likely site for severe seismic or volcanic impacts to occur is at FRA, where the seismic andvolcanic hazards are greatest. However, the Army is expected to have internal capacity to evacuate itspersonnel and to support civilian emergency response efforts in a seismic or volcanic emergency.Alternative B would not cause significant cumulative impacts regarding seismic and volcanic hazards.No other cumulative geologic or soils impacts are expected from Alternative B. Overall, cumulativeimpacts to soils and geologic resources associated with Alternative B would be expected to besignificant but mitigable to less than significant.5.6.2.2 Water ResourcesUSARAK maneuver training has involved stream crossings on Yukon Training Area (YTA), DTA,and TFTA (USARAK 1979a, b). TFTA training has occurred in winter, which prevents directsedimentation impacts due to streambed disturbance. However, erosion at the crossing points mayhave led to sedimentation through runoff. In addition, weapons training involving explosivemunitions may also have had impacts to surface water quality. However, water quality tests haveshown no detectable quantities of munitions constituents in recent studies. This indicates that anyimpacts would be ephemeral at the point and time of impact. Localized contamination frominadvertent chemical releases, such as petroleums, organics, and lubricants, may also have occurred(USARAK 1979a).Past impacts to groundwater on Army lands have occurred due to weapons training (USARAK 1979a,b). Explosive munitions training on the TFTA and YTA impact areas has led to the presence ofunexploded ordnance on USARAK impact areas. Chemical constituents from unexploded ordnancehave the potential to leach through the soil into the aquifer, thereby affecting groundwater quality.However, studies (Houston 2002; Ferrick et al. 2001) indicate that ambient conditions sharply curtailthe probability of groundwater contamination from munitions constituents.Water resources in interior Alaska are likely to be impacted from military activities including thoseconducted by USARAK, U.S. Air Force, Cold Regions Test Center Automotive Test Complex, andthe Space and Missile Defense System. These activities have the potential to alter surface waterquality. The Cold Regions Test Center Automotive Test Complex would be designed to avoidimpacts to Jarvis Creek and its floodplain (Stout 2003b). In addition, some resource extraction, suchas timber harvesting and mining, can alter surface flow or increase sedimentation. These impacts aregenerally short-term.Construction by any of these can alter groundwater recharge regimes, and such impacts are local andlong-term. In addition, disturbance and loss of permafrost can also alter local groundwater flow byincreasing connectivity to lower groundwater sources. Military activities also have the potential toaffect groundwater quality through munitions practice. These impacts can be long-term. Thedevelopment and use of the Cold Regions Test Center Automotive Test Complex would not impactgroundwater quality, although two wells (approximately 400 feet deep each) would be drilled.Infrastructure projects, including the Alaska, Richardson, and Parks Highways and the NorthernIntertie project, can affect surface flow by channelizing flow patterns or altering surface runoff ratesFebruary 2008 5-259 2/25th SBCT Final EIS