2020-03-24_PERMIT FILE - C1981019A (5)

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RULE 2 PERMITS Temperature Temperature data for Craig and Meeker are presented in Table 2.04.8-1, Monthly Normals of Temperature and Precipitation (1941-1970), in Table 2.04.8-4, Monthly Average Temperature (1971-1979) for Craig, Colorado and in Table 2.04.8-5, Monthly Average Temperature (1971- 1979) for Meeker, Colorado. Based on data collected by the United States Department of Commerce,the mean annual temperature of Craig is 42.4°F while the mean annual temperature at Meeker is 44.2°F.Mean maximum and minimum monthly temperatures for both Craig and Meeker are shown in Table 2.04.8-6, Temperature Summary - Means. Wind The synoptic flow in the area is characterized by prevailing westerly winds, which influence air quality in the region. The direction and speed of the winds are greatly affected by the local topography. The general area contains two large drainage basins: the Yampa River Basin and the Williams Fork River drainage system. The Yampa Valley forms a broad canyon which channels the airflow into an east-west orientation reflecting upslope and downslope motion. Similar upslope- downslope wind flow exists in the Williams Fork Valley. The flow draining this Valley is directed northwardly along the high ground west of Craig prior to joining the main stream flowing up and down the Yampa Valley at the end of the ridge. The high frequency of near-calm conditions exists because of the protection afforded by the local terrain in most of the valleys. These conditions generally occur at night and in the early morning. The strongest winds in the area can be expected during the winter and early spring, especially in March, and briefly during summer thunderstorms. The prevailing winds over most of the permit area will be from the southwest at an average speed of approximately 8 to 9 miles per hour; some 10 to 15 percent of the time the wind will blow out of the northeast. Strong winds will occur due to cold fronts and thunderstorms moving through the area, but fair weather winds will rarely exceed 20 to 25 miles per hour. Meteorological Work at Colowyo Site specific meteorology and total suspended particulate analyses for the Colowyo operation are set forth in Exhibit 8, Air Quality Information under the title of"Report of Site Meteorology and Total Suspended Particulate Studies." This one year baseline monitoring program was conducted by Western Scientific Services, Inc. of Fort Collins, Colorado during 1976. Site-specific precipitation data obtained at the Colowyo operation are presented in Table 2.04.8-7, Monthly Precipitation- Colowyo Permit Area. Representative wind roses are set forth in Figure 2.04.8-1, Wind Rose — Mine Site and Figure 2.04.8-2, Wind Rose—Gossard Loadout. Rule 2 Permits 2.04-42 Revision Date: 12/20/19 Revision No.: TR-135