what are these circles on google maps?

Factual Questions
1

If you follow this link…

http://www.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=handle+rd+and+south+ellicott+highway,+colorado&sll=38.823945,-104.381142&sspn=1.596252,2.471924&ie=UTF8&ll=38.827874,-104.36574&spn=0.049881,0.077248&t=h&z=14&iwloc=addr

…It will take you to Colorado. To the right of where the map is centered there are some strange circles designs on the ground. Did I stumble upon the world’s largest crop circle? What are these circles? I should also mention I don’t know anything about farming.

2

Center-pivot irrigation. You can see the boom in most of the circles; in this one, for instance, it’s at about “nine o’clock” on the circle.

3

Missed the edit window — the above link to the detail of the boom doesn’t work. Try this one instead.

4

Incredible. I have never heard of or seen anything like this before.

Thanks, MikeS.

5

You can see these all through southern Alberta. Have a look at this map: Google map of some southern Alberta irrigation.

The advantage is mechanical - if you need to irrigate, you either do this, or you build giant rolling sprinklers that traverse the crop. Having a pivoting sprinkler arm is easier to do. The drawback is that you lose the area of the field between the circle and the rectangular boundary of the land.

6

Which is 4r[sup]2[/sup] - ᴨr[sup]2[/sup], or 4 - 3.1415926… so somewhat less than 25% but more than 20%. Not an insignificant amount, in other words.

7

Modern center pivot systems can have corner fill systems. They’re complicated and expensive, so the payback may be questionable depending on crop.

8

But then, in most of the western US, land is very cheap, and it’s just the water itself and the delivery method that’s expensive. So wasted land that isn’t getting watered isn’t really a big deal

9

Actually it will be less than 20%. Even if you don’t go with the expensive articulating dealie, there’s an end gun with a range of a couple hundred feet that shoots into the corners.

10

There EVERYWHERE around here.

11

They’re… :smack:

12

Does it water outside the edges of the field? Or is the radius of the arm shorter than half the length of the side?

13

I assume it is controlled in such a way that it shoots only into the corners and stops shooting when pointed at the side. It would not be difficult to have a controlled pressure which increases to a max when it gets to a corner and decreases gradually to zero when at the center of a side.

14

Can’t farmers grade the fields so the corners are in low spots so water gravitates to the corners?

15

Not practically.