Owachomo (above) is the smallest and thinnest of the three natural bridges here and is commonly thought to be the oldest. We may never know for certain, as each of the bridges certainly have eroded at different rates. Regardless of its relative age, it is certainly the most fragile and elegant of the three spans, and an awe inspiring feature of erosion.
Bridges dimensions (in feet):
Owachomo : height 106 : span 180 : width 27 : thickness 9
Sipapu : height 220 : span 268 : width 31 : thickness 53
Kachina : height 210 : span 204 : width 44 : thickness 93
How Natural Bridges Form
The rock in the park is a sandstone first formed by windblown sand. The deep, looping White and Armstrong canyons and the three bridges within them can be traced to the relentless action of water against the crossbedded sandstone. The desert stream would occassionally scour its bed with a great head of water and sand, so that conditions for forming natural bridges were set. Kachina and Sipapu straddle streams with long winding curves. Owachomo, now stradling no stream, was apparently cut by the action of two streams.
When a river forms a great looping meander, almost circling back on itself, it can create the thin rock wall in which natural bridges form. Raging flood waters scrape away at both sides of the thin wall. Even during low water, percolation weakens the wall further. Eventually the river breaks through and takes the shorter course under its new bridge, abandoning the old meander. The river continues to wear down the rock, enlarging the hole by cutting itself deeper.
A natural bridge is temporary. Blocks fall from its underside, and its surfaces weather, wear, and weaken. The span of Owachomo, for example, the oldest bridge, has worn thin.
Early in the Monument's development, a dirt road led to Owachomo bridge from the south. It ended at the campground and ranger station directly southwest of the bridge. There were no other roads, and visitors seeking the other two bridges hiked or rode horses through the rugged canyons, often guided by the first "custodian" of the National Monument, Ezekial "Zeke" Johnson. Today, remnants of "Zeke's trail", now on the National Register of Historic Places, can still be seen just across the canyon below Owachomo.
Kachina is "the middle bridge." Spanning the canyon equidistant from both Owachomo and Sipapu bridges. It is larger than Owachomo but smaller than Sipapu. Proving that canyons are dynamic rather than static, approximately 4,000 tons of sandstone fell from the inside of the Kachina bridge opening in June, 1992, enlarging the opening as it has doubtless been enlarged time and time again.
Government surveyor William Douglas dubbed the bridge "Kachina" when he found petroglyphs and pictographs depicting dancing figures carved on the base of the bridge. Douglas assumed that the ancestral Puebloan people who left the ancient rock art were related to the present day Hopi people, and that the painted and carved figures represented Kachina dancers. Before Douglas, local cowboy Jim Scorup named the bridge "Caroline" in honor of his mother. Before that, Cass Hite had named it "Senator."
All the text in this page were lifted from the official park brochure issued by the National Parks Service of the US Department of Interior and their website www.nps.gov/nabr.