SBCT Final EIS - Govsupport.us

Chapter 5 – Environmental Consequenceswater quality are expected to be less than significant because surface water is present onlyintermittently following large storms.Impacts on groundwater quality: Infiltration and percolation of surface water could dissolve andtransport chemicals deposited in surface soils to the subsurface. However, with a few exceptions,most of the mass of chemical residues are expected to dissolve relatively slowly in water and wouldremain in shallow soils. It would require large volumes of recharge to carry dissolved contaminants tothe great depths at which groundwater may occur beneath the PTA and relatively long time periodsfor the chemicals to be transported. Even if relatively soluble compounds, such as perchlorate, weretransported with the recharge, the concentrations would be very dilute when they arrived at the depthof basal groundwater (provided it is present beneath the PTA).There are no groundwater wells in the area, and therefore no groundwater monitoring has beenperformed to confirm that groundwater beneath the PTA has not been affected by chemicalcontaminants. However, groundwater is not used locally as a source of drinking water, so there are noreceptors in the area that would be impacted if trace constituents were to reach the groundwateraquifer. For these reasons, potential impacts on groundwater resources from chemicals generated bycurrent force training or construction activities under the No Action Alternative are considered lessthan significant.Use of new ranges at current levels would continue under the No action Alternative at SBMR, DMR,and KTA, and KLOA. Impacts to surface and groundwater resources from live-fire training would beless than significant. Regulatory, administrative, and additional mitigations described underAlternative A would be implemented to protect water resources from potential impacts resulting fromlive-fire training.5.5.3.1.4 Impacts from Maneuver TrainingSignificant Impacts Mitigable To Less Than SignificantImpact 1: Impacts to surface water: Significant impacts to surface water quality could result from soilerosion associated with training activities at KTA. However, these impacts would be mitigable to lessthan significant level. The use of maneuver areas at PTA are expected to result in less than significantimpacts on surface water, as the 2/25 th ID (L) does not conduct maneuver training as intensively aseither the modular IBCT or the SBCT. The potential for eroding soils to affect surface water qualitywould continue to be mitigable to less than significant or less than significant at all maneuver trainingareas in USAG-HI. ATTACC modeling results indicate that the current land condition has beenaffected by training and that the current rates of soil erosion exceed the goal of long-termsustainability.Regulatory Administrative Mitigation 1: The Integrated Training Area Management program wouldcontinue to be implemented under the No Action Alternative to mitigate the maneuver damage of the2/25 th ID (L) and other units in USAG-HI. This program would continually identify maneuverdamage and take measures, such as reseeding and trail maintenance to prevent impacts to surfacewaters.Less Than Significant ImpactsImpact on surface water quality. The Army and the operator of the harbor are responsible forpreventing spills and for cleaning them up if they occur, according to standard spill prevention andresponse procedures. Activities are not expected to result in any appreciable impacts on the waterFebruary 2008 5-201 2/25th SBCT Final EIS