WSP07593 - Laserfiche WebLink

Home Browse Search

Aspen Highlands Ski Area - Draft EnviroN7lelllal Impat:l Stalemelll Gunnison National Monument, and Maroon Bells-Snowmass, Eagles Nest, and West Elk wildernesses. In addition, a fine particle monitoring system is operating at the Maroon Bells-Snowmass Wilderness. The Clean Air Act (CAA) and new regulations, effective January 31,1994, require conformity with both the NAAQS and SIP. Conformity is deemed to occur when the SIP's purpose of elintinating or reducing the severity and number of violations, or possible violations, of the NAAQS and achieving expeditious attaimnent of such standards are met. Conformity also requires that new activities will not cause or contribute to any new violation of any standard. nor increase the frequency or severity of any existing violation of any standard, nor delay timely attainment of any standard or any required interim emission reductions or other milestones in any area. The new conformity regulations, which contain substantive and procedural requirements for conformity determinations, apply to all federal actions and environmental analyses completed after March 15. 1994. Direct (construction activities, restaurants, etc.) and indirect (traffic generated and associated with the projects development) sources must be considered for the conformity delamination. Since no exceedances of the annual standard for PMIO have been recorded, the SIP does nOl state a design value for the annual standard The SIP demonstrated that the Aspen area would be in attainment of the NAAQS for PMIO by the December 31, 1994, deadline established in the 1990 CAAA, and would be able to maintain the standard for the following 3 years. ENVIRONMENTAL CONSEQUENCES PMIO emissions were determined to be 4,780 lbs per day for 1995 and would likely reach 5,8241bs per day by the year 2000 under the No Action AllalJative. Mobile source CO emission from vehicle exhausl was estimated to be 2,8581bs per day for the 1995 base year bUl would decrease to 2,345 Ibs per day by the year 2000 due to the Federal Motor Vehicle Control Program. Modeled maximum PMIO concentrations in the year 2000 were found to be toO !1g/m' (14 !1g/m' more than during 1995 due to increases in the City of Aspen). The analysis also showed that both the 24-hour and annual standards for the Maroon Bells Class I and surrounding Class IT areas are likely to be affected under extreme meIeOrologicaI conditions by the Aspen non-attainment area. level- l (worst case) and Level-2 (less restrictive) screening results showed at least one exceedance in all five Class I areas, with maximum impact likely to occur in the Maroon Bell Wilderness. Level-I and Level-2 assume that Class I areas are located downwind, which generally is not the case; therefore, Level-3 visibility or region dispersion modeling may improve the evaluation. Under Alternative B, total PMIO emissions due to construction/maintenance of the expanded ski facilities and restaurant would be about 32.640 Ibs (6,528 Ibs over an assumed 5-month construction period). However, compared to the No Action Alternative, there was virtually no difference in the daily emission rates during the winter since the expansion would require only four new snowmobiles to patrol the ski terrain and three extra charbroilers for the restaurant. Base area stationary and mobile sources would remain virtually unchanged. The estimated total emissions for the region would be 5,820 Ibs per day. Modeled maximum PMIO concentrations under Alternative B were found to be virtually identical to the No Action Alternative and there would be no additional impact on visibility. Thus the probability of exceeding the 24-hour 150 !1g/m' would be very low. Alternative B would not add to the impact of the Aspen nonattainment area on the Maroon Bells Class I and surrounding Class IT areas. The mobile source CO emission due to vehicle exhaust would be 2,342lbs per day. which would be virtually identical to CO emissions under the No Action Alternative. According to 40 CFR 93.153(c)(2), the conformity rule does not apply to actions which would result in no emissions increase or an increase in emissions that is clearly de minimi.. No further analysis is required to show conformity to the 24-hour standard Because the proposed a1lalJative would not increase PMIO emissions on a daily basis during the design period, it is also not expected to increase on an annual basis. Under Alternative C, PM,o. and CO emissions due to construction and operation of the ski area. as well as stationary and mobile sources at the base of Aspen Highlands would not differ from Alternative B. 32 Sectioll III Air Quality