National monument, southeastern Utah, U.S. Comprising three large natural bridges carved by two winding streams, it was established in 1908. The largest bridge, Sipapu, is 222 ft (68 m) high and spans 261 ft (80 m). Pictographs were carved on another of the bridges, Kachina, by early cliff dwellers.
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Natural Bridges National Monument is a U.S. National Monument located in about 50 miles north west of the Four Corners boundary of southeast Utah, in the western United States, at the junction of White Canyon and Armstrong Canyon, part of the Colorado River drainage. It features the second and third largest natural bridges in the world, carved from the white Triassic sandstone of the Ceder Mesa Formation that gives White Canyon its name.
The three bridges in the park are named Kachina, Owachomo, and Sipapu, which are all Hopi names. A natural bridge is formed through erosion by water flowing in the stream bed of the canyon. During periods of flash floods, particularly, the stream undercuts the walls of rock that separate the meanders (or 'goosenecks') of the stream, until the rock wall within the meander is undercut and the meander is cut off; the new stream bed then flows underneath the bridge. Eventually, as erosion and gravity enlarge the bridge's opening, the bridge collapses under its own weight. There is evidence of at least two collapsed natural bridges within the Monument.
The Monument's elevation ranges from 1,700 to 2,000 m (5,500 feet to 6,500 feet). The Monument's vegetation is predominantly pinyon-juniper forest, with grass and shrubs (brittle brush, Mormon tea, sage, etc.) typical of high-elevation Utah desert. In the canyons, where there is more water and seasonal streams, riparian desert plants, such as willow, oak and cottonwood trees, thrive. Because the Monument has been closed to grazing for nearly a century, and off-road motorized travel is restricted, Natural Bridges contains extensive areas of undisturbed, mature cryptobiotic soils.
The Monument was nearly inaccessible for many decades (a three-day horseback ride from Blanding, Utah, the nearest settlement), as reflected by the visitor log kept by the Monument's superintendents. The park received little visitation until after the Uranium boom of the 1950s, which resulted in the creation of new roads in the area, including modern-day Highway 95, which was paved in 1976.
The main attractions are the natural bridges, accessible from the Bridge View Drive, which winds along the park and goes by all three bridges, and by hiking trails leading down to the bases of the bridges. There is also a campground and picnic areas within the park. Electricity in the park comes entirely from a large solar array near the visitors center. In 2007, Natural Bridges was named the first International Dark Sky Park by the International Dark-Sky Association. It is a designation which recognizes not only that the park has some of the darkest and clearest skies in all of the United States, but also that the park has made a every effort to conserve the natural dark as a resource worthy of protection.
Horsecollar Ruin is an ancestral Puebloan ruin visible from an overlook a short hike from Bridge View Drive. The site was abandoned more than 700 years ago but is in a remarkable state of preservation, including an undisturbed rectangular kiva with the original roof and interior, and two granaries with unusual oval-shaped doors.
|m (ft)||m (ft)||m (ft)||m (ft)|
|Owachomo||32 (106)||55 (108)||8 (27)||3 (9)|
|Sipapu||67 (220)||82 (268)||9 (31)||16 (53)|
|Kachina||64 (210)||62 (204)||13 (44)||28 (93)|
Animals species found in the National Monument include birds, rabbits, lizards, bobcats, coyotes, bears, mule deer, and mountain lions. Plant species include willow, cottonwood, douglas fir, ponderosa pine, pinyon pine, juniper, grasses, and various shrubs.