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EXHIBIT K CLIMATE AND AIR QUALITY K.1 INTRODUCTION The project is located in a semi-arid, continental climatic region which is characterized by warm summers and dry winters. Sunny days, clear nights, little precipitation, extreme evaporation, and large diurnal temperature changes predominate. The region's complex topography causes considerable variation in site-specific temperature, precipitation, and winds. These influences are less on the plateaus than down in the valleys. K.2 CLIMATOLOGY AND ~4IR QUALITY OF THE PROJECT AREA The climatology of the site is a function of location and elevation. The growing season is approximately 100 days long with a frost-free period of about 60 days. In winter, the average temperature is 20 to 24°F, and the average daily minimum is 5 to 10°F. In summer, the average temperature is i 63 to 69°F, and the average daily maximum is 83 to 88°F. The average annual precipitation is approximately 17 inches, with about 55 percent falling during the period of April through September. About 35 thunderstorms occur faach year, 21 of which are in the summer. Average seasonal snowfall is 40 to 80 inches. The greatest snow depth at any one time during the period of record was 30 inches. On an average of 15 to 30 days, at least 1 inch of snow is on the ground. The number of such days varies greatly from year to year (SCS 1982). The average relative humidity in mid-afternoon is less than 33 percent in spring, and is about 44 percent the rest of the year. Humidity is higher at night year-round, and the average at dawn is about 59 percent. The sun shines 17 percent of t:he time possible in summer, and 61 percent in winter. The prevailing wind is from the southwest, averaging about 7 miles per hour. However, the surface wind patterns are almost entirely dependent on local terrain and ground cover. Gentle air inversions are common at night, and cool air tends to drain into the valleys (SCS 1982). K-1