The Pecos River Flume is an aqueduct over the Pecos River in Carlsbad, New Mexico. It was originally constructed of wood in 1890 as part of the Southern Main Canal to carry irrigation water to dry areas from Lake Avalon. Pecos River-originated water flows through the flume, which once led "Ripley's Believe It or Not'' to feature it as "the world's only river that crosses itself.''
In 1902, a flood destroyed the original structure, which was 475 feet long by 25 feet wide and carried up to eight feet of water. It was replaced in 1903 with a four-span, closed-spandrel concrete arch. Upon its completion, the new aqueduct ranked briefly as the largest concrete structure in the world.
Even to this day, the Pecos River Flume provides water to the Carlsbad Irrigation System, directing much needed resources to local farmlands. It is not always in use, however, and sometimes holds only standing water. There are no signs posted or fences to keep anyone from climbing to the top, but most visitors are content to take photographs of the flume from a distance.
The Pecos River Flume is located off Callaway Drive on Westridge Drive. It is about one block northeast of U.S. Highway 285 near the Comfort Inn. Parking is possible, but not advisable, beneath the fume. Leaking water has been known to rain down on cars below.