The largest tributary of the Rio Culebra is Ventero Creek which rises in New Mexico and flows 25 km (16 miles) northward to join the main stream.

[5] Precipitation increases with altitude and most of the water in the Rio Culebra comes from melted snow and rainfall received at the higher elevations of the Sangre de Cristos.

A weather station near El Valle Creek at an elevation of 3,207 m (10,522 ft) received 635 mm (25.0 in) of precipitation annually on average between 1980 and 2021.

[6] Expansion northward of the Spanish colony in New Mexico was prevented for more than 100 years by the Ute Indians who inhabited the Rio Culebra basin.

The Rio Culebra basin is part of the Sangre de Cristo Land Grant awarded to the family of Carlos Beaubien in 1843.

In 1852, the settlers began digging what became known as the San Luis People's Ditch to irrigate farmland with the water of the Rio Culebra.

Settlers were guaranteed access to the upland areas for grazing livestock, collecting firewood, hunting, and fishing.