SBCT Final EIS - Govsupport.us

Chapter 4 − Impact MethodologyChapter 5 to assess potential impacts related to human exposure to contaminated soils during trainingactivities.Both the Alaska and Colorado alternative installations and associated training areas currentlyaccommodate permanent modular IBCT units that would be replaced by an SBCT unit andpermanently transfer to Hawaii if chosen. This impact analysis focuses on the net differences betweenthe existing impacts resulting from the IBCT training components and impacts that would be causedby SBCT training components on each of the three alternative installations and associated trainingareas.4.3.1.1 Assessment of Mounted Maneuver Training on Land ConditionHawaiiThe Army developed the ATTACC model for the 2004 FEIS for the Transformation of the 2/25 th ID(L) to an SBCT in Hawaii to assess the impacts of mounted maneuver training on land. The first stepin the model was to estimate the training load placed on the land by the vehicles that would be used totransport and accompany troops on maneuvers at the ranges. This training load was measured interms of a standard based on the impact of an Abrams tank per mile of travel during maneuvertraining. The standard unit is referred to as a MIM. Other vehicles have different impacts on landcondition due to their weight, wheel or track configuration, and how they are operated. The effect ofmounted maneuver training on a particular plot of land can be generally described by a curve thatrelates the land condition to the training load. As the training load increases, the condition of the landwould generally decrease because the training load damages vegetation cover and disturbs soils, andthese effects can persist over time. Once initiated, damage to vegetation cover and soils canaccelerate, as eroded areas widen, for example, and soil loss prevents vegetation from becomingestablished. Mounted maneuver training is generally not restricted to roads but is restricted by terrainfactors (slope and vegetation) and can be further restricted by the need to avoid sensitive habitat orcultural sites. Curves that relate land conditions to training load can be developed for small areasbased on detailed information about the susceptibility of the land to the effects of maneuver training,or they can be developed for larger areas, where the effects are not known in as much detailed, but areaveraged. The ATTACC modeling was performed at this broader level of analysis for the 2004 FEISto estimate the overall effects of the proposed actions relative to existing conditions for the entireranges.In modeling the effects on the SBMR, the current land condition was classified as “moderate”, andthe existing annual training load at SBMR was estimated at 16,740 MIMs, and the existing trainingload in SBER was estimated at 11,680 MIMs. The current land condition at DMR was classified as“acceptable” and the existing annual training load at DMR was estimated at 1,710 MIMs. The currentland condition at KTA was classified as “severe” (currently used for high intensity training activities)and the existing annual training load at KTA/KLOA was estimated at 7,210 MIMs. The current landcondition at PTA was classified as “mild” and the existing annual training load at PTA was estimatedat 13,660 MIMs. Changes in the land condition and annual training loads estimated for transition toSBCT maneuver training in these areas under implementation of Alternative A are discussed inChapter 5.AlaskaThe 2004 USARAK Transformation FEIS (USARAK 2004) evaluated the ability of soils tophysically support military vehicle maneuvers, referred to as trafficability, using a study by the ColdRegions Research and Engineering Laboratory (CRREL), which used soil maps compiled via theFebruary 2008 4–5 2/25th SBCT Final EIS