Hydrologic Activity

In the late 1960s, the natural regime of the Arkansas River was altered by the construction of the Pueblo Dam and Reservoir, located 75 miles upstream from the park. The river carries a large bedload of sediment and has been aggrading for the past several decades in the area between La Junta, eight miles upstream, and John Martin Dam, twenty miles downstream.

Complicating the hydrology near the fort is the Ft. Lyon Canal, located a mile to the north. This major canal provides irrigation to the farming area between La Junta and Lamar, Colorado. In June 2003, more than 40,000 acre feet of water was delivered to farms across the valley.

Flooding is a longtime issue at Bent’s Old Fort. In recent decades, the water table has risen, causing standing water in several basement rooms. Concerns that the high water table might damage the fort’s stone-and-adobe foundation of the fort, park staff commissioned a study examining the cause of the flooding. Leakage from the nearby Fort Lyon canal was identified as one contributing factor among many in a complex hydrological picture.

Scientists with the Southern Plains Network collect long-term data on water resources and hydrology at Bent’s Old Fort.