Irrigation has a long history. The basic idea is to get water from a place where it's plentiful to a place where there's not enough to reliably support the growth of crops. Most crops grown in the lowlands of the northern Chihuahuan Desert require irrigation, and the Rio Grande is the primary source. In principle, an irrigation system is simple. Go upstream until you are higher than the fields to be irrigated, dig a ditch from there to the fields, and allow the water to flow. In practice, things tend to be more complicated.
Fields have to be carefully leveled and sloped so that the water will
flow evenly to all parts. Opening the fields directly to the irrigation ditch makes
control difficult. One ingenious solution is the use of siphons, humped pipes that can
be filled with water and the hump placed over the elevated ditch bank. With the ditch
end higher than the field end, the pipe efficiently siphons water into the field with
no energy requirements and no danger of ditch-bank erosion.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.