SBCT Final EIS - Govsupport.us

Chapter 3 ⎯ Affected EnvironmentA ground survey of the immediate and surrounding area detected no readings above background levels.A subsequent survey of the area with more sophisticated equipment again detected no readingsabove background levels.In October 2006, a third survey of the area was conducted in areas made more accessible by a successfulprescribed burn of the impact area. The survey consisted of visual reconnaissance, handheldfield instrument scans for the detection of low-energy radiation, uranium analysis, and alpha/gammaspectroscopy. During this survey, several areas were found with DU particles on top of the groundand several 20-mm tail fin sections were located and left in place. Forty-five separate locationsshowed Gamma levels higher then background. All of these locations were recorded by GPS andmarked with orange flags. In total nine samples were collected (six soil samples and three fragments)and sent to an offsite laboratory for analysis. Laboratory analyses indicated that three soil samplesexhibited uranium-238 above background levels. Additionally, spectroscopy analyses confirmed thatthe three fragments collected are comprised of DU.The Army has been working with and continues to work closely with the Nuclear Regulatory Commission(NRC) and the Hawaii State Department of Health (HDOH) to determine the facts. TheArmy completed a detailed characterization survey of Schofield Barracks’ range and verified thepresence of DU fragments on PTA during a scoping survey. It is also determining, with the State andNRC, an approach to address the potential presence of DU at MMR where overgrowth and explosivehazards precluded the conduct of a scoping study. The Army will continue this collaborative effort asit evaluates the results of these surveys and determines the response required to ensure the protectionof human health and the environment from the potential effects of DU.The Army is coordinating its efforts with the Centers for Disease Control and Prevention to obtaintheir input on the medical aspects of our efforts. Although the DU present at these impact areas doesnot present a hazard to the public, it is a topic of significant interest to the public. All Army samplingdata indicate that the DU remains within the impact area of the range. Currently, Army policy prohibitsthe use of DU ammunition for training worldwide (AR 385–63).Geologic Hazards and SeismicitySchofield Barracks Main Post. Steep slopes, slopes weakened by road cuts, and slopes supported bypoorly consolidated materials are subject to failure. Several soil conditions or situations can induceslope failure in such areas, including soils saturated from heavy precipitation, overloading heavy machineryor structures on weak soils, or seismic shaking. Failure can also occur on gentle slopes forsimilar reasons. Areas of steep slopes that may be particularly susceptible to landslides or slope failure,usually considered slopes greater than 30 percent, are located primarily in the western portion ofSBMP along the ridgeline of the Waianae Range (USAG-HI 2004).The potential for strong ground shaking at SBMP is relatively low due to its distance from the southcoast of the Island of Hawaii, where most modern Hawaiian earthquakes originate. The U.S. GeologicalSurvey (USGS) has prepared maps showing the horizontal ground acceleration in firm rock, as apercentage of the acceleration of gravity, for a given probability of exceedance within a given numberof years. The severity of ground shaking depends on the local geologic conditions. Soft sediments (alluviumfor example) may amplify seismic waves, while wave energy tends to be transmitted efficientlythrough hard rock. According to the USGS National Seismic Hazard Mapping Project, there isonly about a 10 percent chance that ground accelerations of more than 12 percent of gravity wouldoccur in firm rock areas within the southeastern three quarters of Oahu over the next 50 years(USAG-HI 2004).February 2008 3–8 2/25th SBCT Final EIS