Integrated Training Area Management EA and Final FNSI

projects and would result in wide, concave ditches during construction. The concave ditches would bemaintained after construction in order to provide effective site drainage. Gravel pit development andextraction and crushing of gravel would result in some minor adverse impacts including increased soilerosion while pits are active. Soil contamination would also be possible due to high vehicle activity.Gravel pit reclamation, however, would have beneficial impacts on soil resources.Gravel pit reclamation procedures would include temporary grading, ditching, and/or constructing bermsto prevent overland flows from entering the disturbed areas. Slopes would not exceed 2.5:1 to help reduceon-site erosion. Procedures would also recommend a wind and water erosion monitoring program.Permanent reclamation procedures would include utilizing original, on-site material as surface fill. Anyimported fill would be sterilized or covered by a minimum of three feet of on-site material. If available,on-site overburden material would be installed as the top four to six inches on all exposed soils.Military and recreational off-road travel as well as driving on the edges and sides of roads to avoid badroad conditions damages roadways and causes soil compaction and erosion. This would be less likely tooccur if existing roads were in good condition. Additionally, repeated use of firing points and bivouacsites often results in soil compaction and erosion due to heavy vehicular traffic. Road crossings, maneuvertrail upgrade and maintenance, and hardening of roads and pads would help reduce these impacts.Additionally, hardening low water crossings would concentrate vehicular impacts to a specified area. Thiswould minimize impacts to soils along the rest of streambanks. Projected trail upgrade and road/padhardening projects for the next five years include approximately 85 acres impacted at Fort Richardson,245 acres at Fort Wainwright, and 135 acres at Donnelly Training Area (Appendix A). Since theseprojects involve upgrade and maintenance of existing range and training land infrastructure, the majorityof acres affected would be previously disturbed.Erosion and sediment control structures and land grading and shaping would reduce erosion impacts byhelping control surface runoff and sedimentation, and directing water away from erosion-prone areas.Because soils exposed from these and other standard operating procedures are vulnerable to erosion,temporary and permanent soil stabilization practices would improve unstable soils. The most commonrevegetation activity on USARAK lands would be seeding exposed soils. Live staking and fascines(tightly wrapped bundles of willow) would be methods used along streambanks, water courses, anderosion-prone slopes to stabilize soils, control erosion, and prevent bank slope failure.Streambank repair, rock armoring, and barb dikes would all help reduce streambank erosion. Hardeninglow water crossings would also help reduce streambank and bed erosion by providing designated crossinglocations. Water bars would be installed to prevent rill erosion by draining water from the portions of aroadway exceeding 5% slope. Trail closure would allow areas with compacted or eroded soils to recover.Installation and maintenance of berms behind firing targets would contain munitions, helping minimizesoil contamination.Vegetation management practices would also affect soils. Mowing would allow plant material to act as amulch layer. Hand or mechanical vegetation thinning/cutting activities would be determined based on soiltype. Trees would typically be ground or cut flush with ground level, resulting in little or no intrusion intomineral soil. However, training area cleanup would involve the mechanical removal of stumps or treedebris and would disturb soils and prevent tree biomass from decomposing into the soils. Most handclearing would occur on unfrozen hydric soils, while most mechanical operations would be conducted onfrozen soils. Projected thinning projects for the next five years include approximately 20 acres impactedat Fort Richardson and 140 acres at Fort Wainwright. About 100 acres of mowing is planned at DonnellyTraining Area (Appendix A)._____________________________________________________________________________________________Environmental AssessmentUnited States Army Alaska, Integrated Training Area Management ProgramManagement Plan 20