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quality protection under the CAA. Sensitive Class II areas are usually afforded additional <br /> protection under state specific rule making for one or more pollutants. This status elevates them <br /> above ordinary Class II areas which account for every other area of the country that is not <br /> explicitly designated as Class I or Sensitive Class II. <br /> As shown in Figure 3 in Appendix A, the following Class I/sensitive Class II areas are within or <br /> intersect the KFO planning area: Mount Zirkel Wilderness (Class I area - USFS), Eagles Nest <br /> Wilderness (Class I area—USFS), Rawah Wilderness (Class I area—USFS) and Rocky <br /> Mountain National Park (Class I area—NPS). <br /> Figures 4a and 4b in Appendix A provide current trend data for visibility for Mount Zirkel <br /> Wilderness and Rocky Mountain National Park, and deposition data for Rocky Mountain <br /> National Park. In general, trends with a negative slope indicate better atmospheric conditions for <br /> each potentially affected area. <br /> Colorado Climate <br /> Colorado is eighth in size among the 50 states, with an area of 104,247 square miles. The <br /> principal features of the Colorado geography are its inland continental location in the middle <br /> latitudes, and the mountains and ranges extending north and south approximately through the <br /> middle of the State. With an average altitude of about 6,800 feet above sea level, Colorado is the <br /> highest State in the Union. Roughly three-quarters of the Nation's land above 10,000 feet altitude <br /> lies within its borders. The State has 54 mountains 14,000 feet or higher, and about 830 <br /> mountains between 11,000 and 14,000 feet in elevation. <br /> Colorado emerges gradually from the plains of Kansas and Nebraska, and slopes gradually <br /> upward for approximately 200 miles to the base of the foothills of the Rocky Mountains. The <br /> eastern portion of the State is generally level, with rolling prairie broken occasional by hills and <br /> bluffs. The northern part of the plains area slopes to the northeast and the southern part to the <br /> southeast, divided by higher country and hills extending eastward from the mountains near the <br /> center of the State. Elevations along the eastern border range from about 3,350 feet at the lowest <br /> point in the State (where the Arkansas River crosses the border) to nearly 4,000 feet. At <br /> elevations between 5,000 and 6,000 feet the plains give way abruptly to foothills with elevations <br /> of 7,000 to 9,000 feet. Backing the foothills are the mountain ranges above 9,000 feet with the <br /> higher peaks over 14,000 feet. West of these "front ranges" are additional ranges, generally <br /> extending north and south, but with many spurs and extensions in other directions. These ranges <br /> enclose numerous high mountain parks and valleys. Farther westward the mountains give way to <br /> rugged plateau country in the form of high mesas (some more than 10,000 feet in elevation) <br /> which extends to the western border of the State. This land is often cut by rugged canyons, the <br /> work of the many steams fed by accumulations of winter snow. <br /> All rivers in Colorado originate within its borders and flow outward, with the exception of the <br /> Green River, which flows diagonally across the extreme northwestern corner of the State. Four <br /> of the Nation's major rivers have their source in Colorado: the Colorado, the Rio Grande, the <br /> Arkansas, and the Platte. <br /> DOI-BLM-CO-N020-2017-0003 16 <br />