1) An irrigation ditch 2) Irrigation canal 
An acequia (lang) or séquia (langva) is a community-operated watercourse used in Spain and former Spanish colonies in the Americas for irrigation. Particularly in Spain, the Andes, northern Mexico, and the modern-day American Southwest, acequias are usually historically engineered canals that carry snow runoff or river water to distant fields. It...
irrigation ditch
• (n.) A canal or trench for irrigating land.
An irrigation ditch or canal. 
A·ce'qui·a noun [ Spanish ] A canal or trench for irrigating land. [ Spanish Amer.] 
acequias are gravity-driven waterways, similar in concept to a flume. Most are simple ditches with dirt banks, but they can be lined with concrete. They were important forms of irrigation in the development of agriculture in the American Southwest. The proliferation of cotton, pecans and green chile as major agricultural staples owe their progress ...
an irrigation ditch.