SBCT Final EIS - Govsupport.us

Chapter 5 – Environmental ConsequencesSome of these actions are ongoing projects that would continue into the future, while others would bediscrete projects that would be conducted in the reasonably foreseeable future. The following sectionsdescribe the cumulative impacts to each environmental resource that would be expected to result ifAlternative B were implemented.5.6.2.1 Geology, Soils, and SeismicityAlternative B is likely to contribute to cumulative impacts from soil erosion near Delta Junction andFort Greely, which includes Delta Junction, Big Delta, Fort Greely, DTA, GRTA, and the BRTAs.The major historic influences on soil erosion in the area include the disturbance of soils, modificationof slopes and drainage features, and loss or disturbance of vegetation due to agricultural conversion,military activities, fires, roads, modification of slopes and drainage features, and other development.The recent trend for soil erosion and/or loss has been improved in recent years by better managementof disturbed lands and application of BMPs. However, activities that disturb or remove vegetativecover are presently occurring or will occur in the reasonably foreseeable future, which will continueto result in greater soil erosion and loss than without these activities. Use of the training ranges islikely to result in continued enhanced wind soil erosion, as well as compaction, rutting, and damageto permafrost in some areas. These effects are expected to be locally significant. However, at theregional level, the effects are not expected to be significant compared to natural rates of erosion andthe cumulative impacts caused by other activities in the region.Soil resources in interior Alaska are likely to be impacted from other military activities associatedwith Fort Greely DTA, GRTA, and the BRTAs, including USARAK, U.S. Air Force, Cold RegionsTest Center Automotive Test Complex, and the Space and Missile Defense System. These activitieshave the potential contribute to increased soil erosion, compaction, and rutting, as well as damage topermafrost. USARAK mission-essential range improvement and upgrade projects could causenegative impacts to soils at DTA (USARAK 2004). Current USARAK maneuver training hasinvolved stream crossings on, DTA (USARAK 2004). DTA training has occurred in winter, whichprevents direct sedimentation impacts due to streambed disturbance. However, erosion at the crossingpoints may lead to soil erosion and subsequent sedimentation through runoff, as well as damage topermafrost. In addition, weapons training involving explosive munitions may also have had impactsto soils through ordnance impact and residual chemical contamination (USARAK 2004). Most otherplanned military projects will occur on already disturbed areas, such as the cantonment area or impactareas. These projects are sufficiently separated (in time and location) from transformation activities toprevent additive or synergistic impacts to soil. The Cold Regions Test Center Automotive TestComplex would be designed to avoid impacts to Jarvis Creek and its floodplain (Stout 2003).Deployment of the Space and Missile Defense System at Fort Greely could result in cumulativeimpacts to soil resources.Infrastructure projects, including the Alaska, Richardson, and Parks Highways and the Trans-AlaskaPipeline System and Northern Intertie project, could contribute to surface runoff and subsequent soilerosion and sedimentation. Future permafrost melting from road construction and use is expected inthe region. Impacts would be localized and not result in synergistic regional effects. Future naturalgas pipeline construction would disturb area soil and permafrost. Other gas and oil explorationprojects would also negatively impact soil resources. Additionally, some resource extraction, such astimber harvesting and mining, can also contribute to increased soil erosion and subsequentsedimentation. The TAPS, Knox, True North, and Pogo gold mines all have an increased potential todisturb local surface soils. These impacts are generally short-term.Community development can also affect soil resources. Community growth in the Delta Junction andBig Delta areas could lead to increased overland water runoff soil erosion and subsequentFebruary 2008 5-258 2/25th SBCT Final EIS