SBCT Final EIS - Govsupport.us

Chapter 4 − Impact MethodologySoils on the North Texas Range were not considered trafficable enough to sustain year-round militaryvehicle training maneuvers without site modification. The proposed BAX maneuver area could onlysupport 517 Stryker vehicle passes in the summer season without becoming impassible. Winterseason training was not considered affected by trafficability.ColoradoThe DECAM has conducted and consulted several studies as part of their rangeland management planto quantify the effects of military training, including remote sensing from the USGS NationalMapping Division in conjunction with military accounting procedures used to define trainingcharacteristics, erosion and sediment transport surveys, evaluations of the effectiveness of erosioncontrol structures, rangeland health assessments performed by NRCS, as well as ongoing soils andvegetation monitoring. Results from these studies, as they relate to impacts identified in the 2007 FortCarson and PCMS Master Draft Transformation DEISs, were considered in evaluating the impacts tosoils and vegetation caused by the transformation of existing IBCT maneuver training to SBCTmaneuver training components at the Fort Carson and PCMS with implementation of Alternative Cfor this EIS. The assessment of military vehicle use for the 2006 Fort Carson and PCMS Master DraftTransformation DEISs did not involve analysis using units of MIMs, but was rather determined on amore qualitative level with regard to the intensity of the effects in relation to the difference in numberof training rotations, personnel, and equipment for the various types of vehicles. For the purpose ofanalyzing the impacts of SBCT Training on Fort Carson and PCMS for Alternative C of this EIS, theintensity of current IBCT Training was compared to the expected intensity of the proposed SBCTTraining on a qualitative level.4.3.2 Resource-specific significance criteriaFactors considered in determining whether an alternative would have a significant impact on geologicand soil resources were evaluated and distinguished by the degree to which the impact would:• Increase the exposure of people or structures to geologic hazards (such as ground shaking,volcanism, liquefaction, slope failure, expansive soils, and hazardous constituents in soils) thatcould result in injury, acute chronic health problems, loss of life, or major economic loss;• Result in substantial loss of soil (through increased erosion), or loss of access to economicallysignificant mineral deposits;• Adversely affect human health or environmental receptors, such as through exposure to toxicchemicals or irritants present in geologic materials;• Adversely alter existing geologic conditions or processes such that the existing or potentialbenefits of the geologic resource are reduced (such as construction of a jetty that would interferewith sand transport processes and beach formation or increase shore erosion);• Conflict with existing federal, state, or local statutes or regulations;• Permanently alter a unique or recognized geologic feature or landscape;• Substantially alter the existing function of the landscape (such as altering drainage patternsthrough large scale excavation, filling, or grading); or• Disturb or alter unique, rare, or otherwise important paleontological resources, such that thepotential to derive benefits from those resources is reduced. (Note that paleontological resourcesare addressed with archaeological resources under the general heading of cultural resources.)February 2008 4–7 2/25th SBCT Final EIS