SBCT Final EIS - Govsupport.us

Chapter 4 − Impact Methodologyrational threshold value (RTV) that is calculated on the basis of yearly historical fluctuations inpopulation, business sales volume, employment, and income within the ROI. The historical extremesfor the ROI (the calculated RTVs) become the thresholds of significance for social and economicchange. If the estimated effect of each project alternative falls above the positive RTV or below thenegative RTV, the impact could be considered to be substantive.In addition, potential impacts on schools based on the number of schools, existing student population,potential increase in student population, and capacity of the schools that could be affected were alsoassessed. This analysis also includes an assessment of anticipated changes to housing, environmentaljustice, and the protection of children.To determine whether low-income or minority populations could be disproportionately affected by aproject alternative, the proportion of low-income or minority populations in the areas surrounding theproposed project activities were identified. If unusually high percentages of low-income and minoritypopulations were identified, the potential for these populations to be displaced, for their income oremployment to be lost, or for adverse effects to their health or environmental condition from theproposed construction or operational activities were assessed. To evaluate whether children couldencounter disproportionate health or safety effects, the population under the age of 18 surrounding theproposed project activities was computed. The identified potential environmental or health and publicsafety risks were then evaluated based on proximity to populations of children.4.9.2 Resource-specific significance criteriaFactors considered in determining whether an alternative would have a significant impact onsocioeconomic conditions or environmental justice included the extent or degree to which itsimplementation would result in any of the following:• Change the local housing market or vacancy rates, particularly when compared to the availabilityof affordable housing;• Increase student enrollment beyond the capacity of the local schools;• Change any social, economic, physical, environmental, or health conditions so as todisproportionately affect low-income or minority populations; or• Disproportionately endanger children in areas on or near the proposed project activities orinstallations.4.10 HAZARDOUS MATERIALS AND HAZARDOUS WASTE4.10.1 Resource-specific Impact Analysis MethodologyNumerous federal, state, and local laws regulate the storage, use, recycling, disposal, andtransportation of hazardous materials and waste. The methods for assessing potential hazardsassociated with hazardous materials and wastes for each project alternative generally include thefollowing:• Reviewing and evaluating each of the Alternatives to identify the action’s potential to usehazardous materials or to generate hazardous waste based on the activities proposed;• Comparing the location of each proposed project activity with baseline data on known orpotentially contaminated areas (such as potentially UXO-contaminated land);February 2008 4–13 2/25th SBCT Final EIS