SBCT Final EIS - Govsupport.us

CHAPTER 3AFFECTED ENVIRONMENTThis chapter describes the affected environment for the project alternatives. The affected environmentis the portion of the existing environment that could be affected by the project. In instances where theaffected environment is thoroughly described in previous NEPA documents, a summary is includedhere and the original document is referenced for further details.The affected environment varies for each resource and location. Both the nature of the resource andcomponents of the proposed project and alternatives dictate this variation. The following sectionsconcentrate on providing only the specific environmental information necessary to assess the potentialeffects of the Proposed Action and alternatives.3.1 ALTERNATIVE A — PERMANENTLY STATION THE 2/25TH SBCTAT SCHOFIELD BARRACKS MILITARY RESERVATION WHILECONDUCTING REQUIRED TRAINING AT MILITARY TRAININGSITES IN HAWAII3.1.1 GEOLOGY, SOILS, AND SEISMICITYThe geologic history of the formation of the Hawaiian Islands and the physiography, geology, soils,and seismicity of the applicable military installations associated with Alternative A are presented belowas they pertain to the existing conditions used later in Chapter 5 to assess the potential effects ofimplementation of Alternative A. The soils potentially affected are summarized with attention paidparticularly to areas covered by soils exhibiting rapid runoff, severe erosion potential, high compactionor shrink-swell potential, or other soil hazards that associated activities could exacerbate or thatcould impact infrastructure related to associated activities. Similarly, chemical constituents in soilsand geologic hazards and seismicity associated with the potentially affected applicable installations.The region of influence (ROI) for geologic and soil impacts of the project is all areas in which project-relatedactivities may occur, including the footprint of each training and construction area and thecorridors of the military vehicle roads. It also includes adjacent areas that may be affected by geologicprocesses in the project area. An example would be downslope areas adjacent to a roadcut or embankmentthat might be affected by slope failure. The ROI studied for the purpose of this analysis isdefined by the legal boundaries of the applicable military reservations associated with each alternative,as shown in Figure 3–1.3.1.1.1 Schofield Barracks Military ReservationPhysiographySchofield Barracks Main Post. Most of the SBMP is in the Schofield Plateau geomorphic province,which is a broad interior highland that lies between the Waianae Range and the Koolau Range. Thewestern side of the SBMP lies within the Waianae Range geomorphic province (USAG-HI 2004).The SBMP is bounded on the east by Kaukonahua Stream, Wahiawa Reservoir, the town of Wahiawa,and Route 750, and it extends westward to the ridgeline of the Waianae Range. Figure 3–1shows the location of SBMR and some of the other major features discussed in this section.February 2008 3–1 2/25th SBCT Final EIS