From The Pueblo Chieftain:
Originally a long, shallow, earthwork excavation, this “acequia” or gravity-fed irrigation channel was hand-dug by San Luis’ first settlers to channel water for crops and livestock from the Culebra River and its tributaries. Extending 4 miles west from La Vega, the town’s communal grazing land, it is the oldest continuously used, community irrigation ditch in Colorado.
According to a plaque at the now-concrete-lined “acequia madre” portion of the channel on the south side of town, the People’s Ditch was granted the first adjudicated water rights in what is now Colorado. Referred to as “court decree priority No. 1” and dating from April 10, 1852, these rights were conveyed just 370 days after San Luis was established — and 24 years before Colorado became a state.
Today, the ditch serves some 16 “parciantes” or affiliated water-users, and irrigates more than 2,000 acres of hay and other crops. It also stands as a legacy to its builders, among them Dario Gallegos, a founder of San Luis who opened the town’s first store in 1857.
More Rio Grande Basin coverage here.