After spending several hours with Google Earth going over the entire 300 by 400 mile area of these grooves spaced a mile apart, and expanding down to 50 feet resolution to view some of them in various areas, I absolutely disagree with you. I do not know of and cannot imagine any natural force that would create the uniformity of size and spacing shown here. There are some minor shifts in directionality which would be explained by a different period in history and leadership. Also some areas appear to have had more environmental effects which have caused damage or partial disappearance, but all I can say is take a good long look, up high and down close. And if you can come up with any geophysical rather than human explanation, I would like to hear it.
Well that settles it :-) follow the articles I looked up online afterwards where dozens and dozens of scientists and archaeologists refute it mean nothing now :-)