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2.2 Community Description Chaffee County is located in south-central Colorado. It is bordered on the north by Lake and Pitkin Counties, on the west by Gunnison County, on the south by Saquache County, on the southeast by Fremont County, and the northeast by Park County. According to U.S. Bureau of the Census figures, the population of Chaffee County increased from 10,162 in 1970 to 13,227 in 1980 (Reference 7). The topography of Chaffee County is influenced by two major mountain ranges separated by a broad valley. These ranges, the Sawatch Range in the western part of the county and the .Misquito Range in the. eastern part, and the intervening valley are the result of faulting. The Arkansas River occupies this down-dropped trough. The Continental Divide runs along the crest of the Sawatch Range. Elevations along the Continental Divide range from 11,000 to 13,000 feet National Geodetic Vertical Datum (NGVD). All of the streams studied in detail originate in the Sawatch range and are tributaries to the South Arkansas or Arkansas Rivers. The upper sections of these tributary drainage basins are characterized by deep to moderately deep soils, with rock outcrops and good per- meability, and overlying metamorphic or granitic rocks. Vegetation is typically native grasses, shrub, or forestland. The lowest elevations in the basins range from 1,000 to 1,900 feet NGVD. The lower reaches of these basins consist of relatively narrow flood plains separated by dry uplands. Flood plain vegetation is lush and diverse, consisting of cottonwood, willow, alder, pinion pine, ponderosa pine, and other trees, shrubs, and grasses. Upland vege- tation is typically pinion pine, sage brush, and dry grasses. The climate of Chaffee County is semiarid; however, variability is caused by the range of elevations in the county. The lower ele- vations are dry and mild. Annual precipitation averages approxi- mately 11 inches with a normal mean temperature range of 250F in January to 640F in July. Higher elevations are cooler and wetter, with as much as 30 inches of precipitation falling mainly as snow. The flood plains of the SOuth Arkansas River, Poneha Creek, and Cottonweed Creek in the vicinity of Buena vista are heavily developed with predominantly single-family homes. Some areas also contain commercial development. The flood plains of Chalk Creek and the upstream portions of Cottonwood Creek are relatively undeveloped. However, sections of the Chalk Creek flood plain upstream of Mt. Princeton Hot Springs have been subdivided for home construction. 4