If that's what they're called, and asking because I don't know. Can the green and black plastic boxes buried in the yard to cover the valves, be raised a few inches without bothering the plumbing? Mine have sunk a few inches making a low area that stands in water after a rain or lawn watering. I'd like to pull it up about 3" and surround with sand or topsoil to eliminate the low area. Thanks.

Yes you can raise them or even better add another box stacked on top to get to grade level. The only way you could disturb the plumbing is by pushing it down or running it over leading to it going down on the pipe. All of this being said, you're still gonna have water in the boxes. It's just a fact of life, but as long as your installers used waterproof wire connectors, there's no issue with them constantly being underwater.

Thanks and good idea. I can just remove the cover of the old one and put the new box over.

When I replaced valves, I threw a couple bricks down under the edges of the plastic covers to prop them up when I filled the hole back in. I like the idea of adding a second cover on top even better, though.