In the comments under the video there's a link to this site: http://changingpower.net/mystery-in-the-alvord-desert/
According to the blog, the group of people drawing the giant Sri Yantra "...didn’t seek publicity but wanted to find out if the ancient symbol would enliven local laws of nature in some perceptible way."
It's interesting also to read what the article has to say about how the group created the Sri Yantra:
"During the arduous weeks of making the Sri Yantra, the group daily walked several miles from camp to the work site rather than use vehicles. Instead of expensive surveying tools, they used sun shadows, ancient prinsiples of geometry, long wires, binoculars, flags and sharpened poles. To inscribe the lines, three crew members pulled the garden cultivator while a fourth steered. They reverently etched a quarter-mile-across Sri Yantra onto forty acres. It contained more than thirteen miles of lines, four inches deep.
As soon as they finished plowing the last line, rain clouds began collecting in the southern sky. An hour later high winds and lightning swept the area. A downpour chose that one valley, drawing envious comment from a nearby rancher who wanted rain. It dissolved footprints and left the design varnished like a completed painting."
The article goes on to describe several other similar projects of Bill Witherspoon, one of the group members, and as far as I can see the story presented in the blog sounds credible.