The Spanish word acequia comes from Classical Arabic as-sāqiya, which has the double meaning of 'the water conduit' or 'one that bears water' and the 'barmaid'. The Arabs brought the technology to Iberia during their occupation of the Iberian peninsula. The technology was adopted later by the Spanish and Portuguese, utilized throughout their conquered lands, except in e.g. Mendoza, Argentina where acequias today run along both sides of all city streets but originally were dug all around by the indigenous Huarpes long before the arrival of the Spanish. In the United States, the oldest acequias were established more than 400 years ago; many continue to provide a primary source of water for farming and ranching ventures in areas of the United States once occupied by Spain or Mexico including the region of northern New Mexico and south central Colorado known as the Upper Rio Grande watershed or Rio Arriba. Acequias are gravity chutes, similar in concept to flumes. Some acequias are conveyed through pipes or aqueducts, of modern fabrication or decades or centuries old. The majority, however, are simple open ditches with dirt banks. In many communities, the ditchbanks are important routes for non-motorized travel. Researchers affiliated with the Rio Grande Bioregions Project at Colorado College initiated a pioneering collaborative, farmer-led, and interdisciplinary study of Colorado and New Mexico acequias in 1995-1999. Among the most significant findings of this study was that the acequia farms provide vital ecosystem and economic base services to the regions in which they are located. One study, as reported in Peña, found that acequia agroecosystems promote soil conservation and soil formation, provide terrestrial wildlife habitat and movement corridors; protect water quality and fish habitat, promote the conservation of domesticated biodiversity of land race heirloom crops, and encourage the maintenance of a strong land and water ethic and sense of place, among other ecological and economic base values. This pioneering research on acequia ecosystem services, led by environmental anthropologist Devon G. Peña, has more recently been confirmed in other studies. Known among water users simply as the Acequia, various legal entities embody the community associations, or acequia associations, that govern members' water usage, depending on local precedents and traditions. An acequia organization often must include commissioners and a majordomo who administers usage of water from a ditch, regulating which holders of water rights can release water to their fields on which days. In New Mexico, by state statute, acequias as registered bodies must have three commissioners and a mayordomo. Irrigation and conservation districts typically have their own version of mayordomos, usually referred to as "ditch riders" by members of the districts. In recent years, acequias in New Mexico and Colorado have successfully developed and implemented changes in state water laws to accommodate the unique norms, customs, and practices of the acequia systems. The customary law of the acequia is older than and at variance with the Doctrine of Prior Appropriation, and the statutes promulgating acequia water law represent a rare instance of water pluralism in the context of Western water law in the United States. For example, the Doctrine of Prior Appropriation is based on the principle of "first in use, first in right," while acequia norms incorporate not just priority but principles of equity and fairness. This is evident in the fact that Prior Appropriation considers water to be a commodity owned by private individuals while acequia systems treat water as a community resource that irrigators have a shared right to use, manage, and protect. While Prior doctrines allow for water to be sold away from the basin of origin, the acequia system prohibits the transference of water from the watershed in which it is situated and thus considers water as an "asset-in-place". The Prior regime is based on a governance regime in which the members of a mutual ditch company will vote based on their proportional ownership of shares so that larger farmers have more votes. In contrast, the acequia system follows a "one farmer, one vote" system that has led researchers to consider this a form of "water democracy". Acequia water law also requires that all persons with irrigation rights participate in the annual maintenance of the community ditch including the annual spring time ditch cleanup known as the limpieza y saca de acequia.
Hydropower generation
can be installed in irrigation canals for electricity generation. "Irrigation districts across the U.S. have installed power plants at diversion points and in-canal drops, which are traditionally used for flow measurement, to stabilize upstream heads and to dissipate energy where there is significant elevation change throughout the canal system."
